Trial Outcomes & Findings for A Clinical Trial to Evaluate Prophylactic Emicizumab Versus no Prophylaxis in Hemophilia A Participants Without Inhibitors (NCT NCT02847637)

Last Updated: 2022-11-16

Results Overview

The number of treated bleeds over the efficacy period is presented as an annualized bleeding rate (ABR) that was assessed using a negative binomial (NB) regression model, which accounts for different follow-up times, with the number of bleeds as a function of randomization and the time that each participant stays in the study (i.e., length of the efficacy period) included as an offset in the model. The model also includes the number of bleeds (\<9 or ≥9) in the last 24 weeks prior to study entry as a stratification factor. A bleed is considered a "treated bleed" if it is directly followed (i.e., no intervening bleed) by a hemophilia medication reported to be a "treatment for bleed", irrespective of the time between treatment and the preceding bleed. Bleeds due to surgery/procedure are excluded.

Recruitment status

COMPLETED

Study phase

PHASE3

Target enrollment

152 participants

Primary outcome timeframe

From Baseline to at least 24 weeks (median [min-max] efficacy periods for Arm C: 24.00 [14.4-25.0] weeks; Arm A: 29.57 [17.3-49.6] weeks; Arm B: 31.29 [3.3-50.6] weeks; Arm D: 33.14 [18.4-48.6] weeks)

Results posted on

2022-11-16

Participant Flow

A total of 161 participants were screened; 9 failed screening, and 152 participants, who had previously received either episodic or prophylactic treatment with FVIII agents, were enrolled in this study. Participants in Arms C, A, and B were randomized in a 1:2:2 ratio, respectively; participants in Arm D were enrolled without randomization.

Participant milestones

Participant milestones
Measure	Arm C (Control): No Prophylaxis, Then Emicizumab Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial. After completing 24 weeks of no prophylaxis (i.e., episodic FVIII treatment) on study, then they were given the opportunity to switch to emicizumab prophylaxis of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm A: Emicizumab 1.5 mg/kg QW Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.
Overall Study STARTED	18	36	35	63
Overall Study Completed First 24 Weeks of Treatment	16	35	34	63
Overall Study Emicizumab Dose Was Up-Titrated	0	1	1	7
Overall Study Opted to Change Emicizumab Dosing Regimen	1	3	1	1
Overall Study COMPLETED	17	34	34	63
Overall Study NOT COMPLETED	1	2	1	0

Reasons for withdrawal

Reasons for withdrawal
Measure	Arm C (Control): No Prophylaxis, Then Emicizumab Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial. After completing 24 weeks of no prophylaxis (i.e., episodic FVIII treatment) on study, then they were given the opportunity to switch to emicizumab prophylaxis of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm A: Emicizumab 1.5 mg/kg QW Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.
Overall Study Withdrawal by Subject	0	1	1	0
Overall Study Lost to Follow-up	1	1	0	0

Baseline Characteristics

A Clinical Trial to Evaluate Prophylactic Emicizumab Versus no Prophylaxis in Hemophilia A Participants Without Inhibitors

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Arm C (Control): No Prophylaxis, Then Emicizumab n=18 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial. After completing 24 weeks of no prophylaxis (i.e., episodic FVIII treatment) on study, then they were given the opportunity to switch to emicizumab prophylaxis of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm A: Emicizumab 1.5 mg/kg QW n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Total n=152 Participants Total of all reporting groups
Age, Continuous	37.8 years STANDARD_DEVIATION 12.9 • n=5 Participants	39.8 years STANDARD_DEVIATION 14.0 • n=7 Participants	40.4 years STANDARD_DEVIATION 11.4 • n=5 Participants	36.4 years STANDARD_DEVIATION 14.4 • n=4 Participants	38.3 years STANDARD_DEVIATION 13.5 • n=21 Participants
Sex: Female, Male Female	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants	0 Participants n=21 Participants
Sex: Female, Male Male	18 Participants n=5 Participants	36 Participants n=7 Participants	35 Participants n=5 Participants	63 Participants n=4 Participants	152 Participants n=21 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	0 Participants n=5 Participants	4 Participants n=7 Participants	5 Participants n=5 Participants	7 Participants n=4 Participants	16 Participants n=21 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	17 Participants n=5 Participants	32 Participants n=7 Participants	30 Participants n=5 Participants	53 Participants n=4 Participants	132 Participants n=21 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	1 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	3 Participants n=4 Participants	4 Participants n=21 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants	0 Participants n=21 Participants
Race (NIH/OMB) Asian	4 Participants n=5 Participants	6 Participants n=7 Participants	10 Participants n=5 Participants	12 Participants n=4 Participants	32 Participants n=21 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants	1 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants	1 Participants n=21 Participants
Race (NIH/OMB) Black or African American	3 Participants n=5 Participants	3 Participants n=7 Participants	1 Participants n=5 Participants	1 Participants n=4 Participants	8 Participants n=21 Participants
Race (NIH/OMB) White	11 Participants n=5 Participants	24 Participants n=7 Participants	20 Participants n=5 Participants	47 Participants n=4 Participants	102 Participants n=21 Participants
Race (NIH/OMB) More than one race	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants	0 Participants n=21 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	2 Participants n=7 Participants	4 Participants n=5 Participants	3 Participants n=4 Participants	9 Participants n=21 Participants
Number of Participants with <9 or ≥9 Bleeds in the Last 24 Weeks Prior to Study Entry Less Than (<) 9 Bleeds	4 Participants n=5 Participants	9 Participants n=7 Participants	5 Participants n=5 Participants	53 Participants n=4 Participants	71 Participants n=21 Participants
Number of Participants with <9 or ≥9 Bleeds in the Last 24 Weeks Prior to Study Entry Greater Than or Equal To (≥) 9 Bleeds	14 Participants n=5 Participants	27 Participants n=7 Participants	30 Participants n=5 Participants	10 Participants n=4 Participants	81 Participants n=21 Participants
Number of Target Joints in the Last 24 Weeks Prior to Study Entry	2.2 target joints STANDARD_DEVIATION 1.4 • n=5 Participants	2.1 target joints STANDARD_DEVIATION 1.4 • n=7 Participants	2.2 target joints STANDARD_DEVIATION 1.7 • n=5 Participants	1.0 target joints STANDARD_DEVIATION 1.6 • n=4 Participants	1.7 target joints STANDARD_DEVIATION 1.6 • n=21 Participants

PRIMARY outcome

Timeframe: From Baseline to at least 24 weeks (median [min-max] efficacy periods for Arm C: 24.00 [14.4-25.0] weeks; Arm A: 29.57 [17.3-49.6] weeks; Arm B: 31.29 [3.3-50.6] weeks; Arm D: 33.14 [18.4-48.6] weeks)

Population: All participants, which includes those randomized to Arms A, B, and C, and those enrolled in Arm D of the study.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=18 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Annualized Bleeding Rate (ABR) for Treated Bleeds	38.2 treated bleed rate per year Interval 22.86 to 63.76	1.5 treated bleed rate per year Interval 0.89 to 2.47	1.3 treated bleed rate per year Interval 0.75 to 2.25	1.6 treated bleed rate per year Interval 1.07 to 2.44	—	—

SECONDARY outcome

Population: All participants, which includes those randomized to Arms A, B, and C, and those enrolled in Arm D of the study.

The number of all bleeds over the efficacy period is presented as an annualized bleeding rate (ABR) that was assessed using a NB regression model, which accounts for different follow-up times, with the patient's number of bleeds as a function of randomization and the time that each patient stays in the study (i.e., length of the efficacy period) included as an offset in the model. The model also includes the number of bleeds (\<9 or ≥9) in the last 24 weeks prior to study entry as a stratification factor. "All bleeds" comprises both treated and non-treated bleeds. In this definition, all bleeds are included, irrespective of treatment with coagulation factors, with the following exception: bleeds due to surgery/procedure are excluded.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=18 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Annualized Bleeding Rate (ABR) for All Bleeds	47.6 all bleed rate per year Interval 28.45 to 79.59	2.5 all bleed rate per year Interval 1.63 to 3.9	2.6 all bleed rate per year Interval 1.63 to 4.29	3.3 all bleed rate per year Interval 2.22 to 4.83	—	—

SECONDARY outcome

Population: All participants, which includes those randomized to Arms A, B, and C, and those enrolled in Arm D of the study.

The number of treated joint bleeds over the efficacy period is presented as an annualized bleeding rate (ABR) that was assessed using a NB regression model, which accounts for different follow-up times, with the patient's number of bleeds as a function of randomization and the time that each patient stays in the study (i.e., length of the efficacy period) included as an offset in the model. The model also includes the number of bleeds (\<9 or ≥9) in the last 24 weeks prior to study entry as a stratification factor. A "joint bleed" is defined as a bleed reported as "joint" and with at least one of the following symptoms: increasing swelling or warmth of the skin over the joint; and/or increasing pain, decreased range of motion, or difficulty using the joint compared with baseline. It is considered a "treated joint bleed" if it is directly followed (i.e., no intervening bleed) by a hemophilia medication reported to be a "treatment for bleed". Bleeds due to surgery/procedure are excluded.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=18 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Annualized Bleeding Rate (ABR) for Treated Joint Bleeds	26.5 treated joint bleed rate per year Interval 14.67 to 47.79	1.1 treated joint bleed rate per year Interval 0.59 to 1.89	0.9 treated joint bleed rate per year Interval 0.44 to 1.67	1.2 treated joint bleed rate per year Interval 0.7 to 2.01	—	—

SECONDARY outcome

Population: All participants, which includes those randomized to Arms A, B, and C, and those enrolled in Arm D of the study.

The number of treated spontaneous bleeds over the efficacy period is presented as an annualized bleeding rate (ABR) that was assessed using a NB regression model, which accounts for different follow-up times, with the patient's number of bleeds as a function of randomization and the time that each patient stays in the study (i.e., length of the efficacy period) included as an offset in the model. The model also includes the number of bleeds (\<9 or ≥9) in the last 24 weeks prior to study entry as a stratification factor. A bleed is classified as "spontaneous" if there is no other known contributing factor such as trauma or procedure/surgery. A "treated spontaneous bleed" is a spontaneous bleed that is directly followed (i.e., no intervening bleed) by a hemophilia medication reported to be a "treatment for bleed". Bleeds due to surgery/procedure are excluded.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=18 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Annualized Bleeding Rate (ABR) for Treated Spontaneous Bleeds	15.6 treated spontaneous bleed rate per year Interval 7.6 to 31.91	1.0 treated spontaneous bleed rate per year Interval 0.48 to 1.91	0.3 treated spontaneous bleed rate per year Interval 0.11 to 0.75	0.5 treated spontaneous bleed rate per year Interval 0.23 to 0.94	—	—

SECONDARY outcome

Population: All participants, which includes those randomized to Arms A, B, and C, and those enrolled in Arm D of the study.

The number of treated target joint bleeds over the efficacy period is presented as an annualized bleeding rate (ABR) that was assessed using a NB regression model, which accounts for different follow-up times, with the patient's number of bleeds as a function of randomization and the time that each patient stays in the study (i.e., length of the efficacy period) included as an offset in the model. The model also includes the number of bleeds (\<9 or ≥9) in the last 24 weeks prior to study entry as a stratification factor. A "target joint bleed" is defined as a bleed reported as a joint bleed into a target joint, defined as at least 3 bleeds into the same joint during the last 24 weeks prior to study entry. It is considered a "treated target joint bleed" if it is directly followed (i.e., no intervening bleed) by a hemophilia medication reported to be a "treatment for bleed". Bleeds due to surgery/procedure are excluded.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=18 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Annualized Bleeding Rate (ABR) for Treated Target Joint Bleeds	13.0 treated target joint bleed rate per year Interval 5.22 to 32.33	0.6 treated target joint bleed rate per year Interval 0.28 to 1.42	0.7 treated target joint bleed rate per year Interval 0.27 to 1.64	0.6 treated target joint bleed rate per year Interval 0.26 to 1.53	—	—

SECONDARY outcome

Timeframe: Efficacy periods: At least 24 weeks prior to study entry (median [min-max] for Dnisp-FVIII Prophylaxis: 30.07 [5.0-45.1] weeks); and From Baseline to at least 24 weeks on study (median [min-max] for Dnisp-Emicizumab Prophylaxis: 33.71 [20.1-48.6] weeks)

Population: Intra-participant comparison in the NIS population previously treated with FVIII prophylaxis (NISP), which includes all participants who had received FVIII prophylaxis in NIS BH29768 prior to study entry in Arm D.

This is an intra-participant comparison of the annualized bleeding rate (ABR) for treated bleeds on study versus pre-study in the NIS population previously treated with FVIII prophylaxis in NIS BH29768. The number of treated bleeds over the efficacy period is presented as an ABR that was assessed using a NB regression model, which accounts for different follow-up times, with the number of bleeds as a function of treatment and the time that each participant stays in the study (i.e., length of the efficacy period) included as an offset in the model. The model also includes a repeated statement to account for intra-participant comparison. A bleed is considered a "treated bleed" if it is directly followed (i.e., no intervening bleed) by a hemophilia medication reported to be a "treatment for bleed", irrespective of the time between treatment and the preceding bleed. Bleeds due to surgery/procedure are excluded.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=48 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=48 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Intra-Participant Comparison of ABR for Treated Bleeds on Study Versus Pre-Study in Participants From the Non-Interventional Study Population Previously Treated With Factor VIII (FVIII) Prophylaxis (NISP)	4.8 treated bleed rate per year Interval 3.22 to 7.09	1.5 treated bleed rate per year Interval 0.98 to 2.33	—	—	—	—

SECONDARY outcome

This is an intra-participant comparison of the annualized bleeding rate (ABR) for all bleeds on study versus pre-study in the NIS population previously treated with FVIII prophylaxis in NIS BH29768. The number of all bleeds over the efficacy period is presented as an ABR that was assessed using a NB regression model, which accounts for different follow-up times, with the participant's number of bleeds as a function of treatment and the time that each participant stays in the study (i.e., length of the efficacy period) included as an offset in the model. The model also includes a repeated statement to account for intra-participant comparison. "All bleeds" comprises both treated and non-treated bleeds. In this definition, all bleeds are included, irrespective of treatment with coagulation factors, with the following exception: bleeds due to surgery/procedure are excluded.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=48 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=48 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Intra-Participant Comparison of ABR for All Bleeds on Study Versus Pre-Study in Participants From the Non-Interventional Study Population Previously Treated With FVIII Prophylaxis (NISP)	8.9 all bleed rate per year Interval 5.72 to 13.87	3.3 all bleed rate per year Interval 2.17 to 5.06	—	—	—	—

SECONDARY outcome

Timeframe: Efficacy periods: At least 24 weeks prior to study entry (median [min-max] for A+Bnise-FVIII Episodic: 25.71 [15.4-40.9] weeks); and From Baseline to at least 24 weeks on study (median [min-max] for A+Bnise-Emicizumab: 34.71 [24.1-50.6] weeks)

Population: Intra-participant comparison in the NIS population previously treated with episodic FVIII (NISE), which includes all participants who had received episodic FVIII in NIS BH29768 prior to study entry in Arms A and B (pooled data).

This is an intra-participant comparison of the annualized bleeding rate (ABR) for treated bleeds on study versus pre-study in the NIS population previously treated with episodic FVIII in NIS BH29768. The number of treated bleeds over the efficacy period is presented as an ABR that was assessed using a NB regression model, which accounts for different follow-up times, with the number of bleeds as a function of treatment and the time that each participant stays in the study (i.e., length of the efficacy period) included as an offset in the model. The model also includes a repeated statement to account for intra-participant comparison. A bleed is considered a "treated bleed" if it is directly followed (i.e., no intervening bleed) by a hemophilia medication reported to be a "treatment for bleed", irrespective of the time between treatment and the preceding bleed. Bleeds due to surgery/procedure are excluded.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=20 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=20 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Intra-Participant Comparison of ABR for Treated Bleeds on Study Versus Pre-Study in Participants From the NIS Population Previously Treated With Episodic FVIII (NISE)	34.4 treated bleed rate per year Interval 27.45 to 43.14	1.0 treated bleed rate per year Interval 0.43 to 2.54	—	—	—	—

SECONDARY outcome

This is an intra-participant comparison of the annualized bleeding rate (ABR) for all bleeds on study versus pre-study in the NIS population previously treated with episodic FVIII in NIS BH29768. The number of all bleeds over the efficacy period is presented as an ABR that was assessed using a NB regression model, which accounts for different follow-up times, with the participant's number of bleeds as a function of treatment and the time that each participant stays in the study (i.e., length of the efficacy period) included as an offset in the model. The model also includes a repeated statement to account for intra-participant comparison. "All bleeds" comprises both treated and non-treated bleeds. In this definition, all bleeds are included, irrespective of treatment with coagulation factors, with the following exception: bleeds due to surgery/procedure are excluded.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=20 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=20 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Intra-Participant Comparison of ABR for All Bleeds on Study Versus Pre-Study in Participants From the NIS Population Previously Treated With Episodic FVIII (NISE)	39.6 all bleed rate per year Interval 31.94 to 49.04	1.6 all bleed rate per year Interval 0.85 to 2.92	—	—	—	—

SECONDARY outcome

Timeframe: Baseline, Week 25

Population: Adult participants randomized to Arms A, B, and C. The number analyzed represents participants who provided responses at Baseline and Week 25.

The Haem-A-QoL questionnaire has been developed and used in hemophilia A participants, assessing very specific aspects of dealing with hemophilia. The questionnaire consists of items pertaining to 10 domains: physical health, sports and leisure, school and work, dealing with hemophilia, family planning, feeling, relationships, treatment, view of yourself, and outlook for the future. The total score for each domain ranges from 0 to 100 with lower scores reflective of better quality of life. Physical Health domain score is reported (range 0 to 100, with lower scores reflective of better physical health). The means were derived via an analysis of covariance (ANCOVA) model and have been adjusted for the following co-variates: baseline score, treatment group, and treatment by baseline interaction term.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=13 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=34 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=29 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Hemophilia A Quality of Life (Haem-A-QoL) Questionnaire Physical Health Subscore for Adult Participants (≥18 Years of Age) in the Randomized Population at Week 25	44.32 units on a scale Standard Deviation 17.15	31.81 units on a scale Standard Deviation 27.86	28.35 units on a scale Standard Deviation 25.57	—	—	—

SECONDARY outcome

Timeframe: Baseline, Week 25

Population: Adult participants randomized to Arms A, B, and C. The number analyzed represents participants who provided responses at Baseline and Week 25.

The Haem-A-QoL questionnaire has been developed and used in hemophilia A participants, assessing very specific aspects of dealing with hemophilia. The questionnaire consists of items pertaining to 10 domains: physical health, sports and leisure, school and work, dealing with hemophilia, family planning, feeling, relationships, treatment, view of yourself, and outlook for the future. The total score for each domain ranges from 0 to 100 with lower scores reflective of better quality of life. Haem-A-QoL Total Score is the average of all domain scores and it ranges from 0 to 100, with lower scores reflective of better quality of life. The means were derived via an analysis of covariance (ANCOVA) model and have been adjusted for the following co-variates: baseline score, treatment group, and treatment by baseline interaction term.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=13 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=34 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=29 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Haem-A-QoL Questionnaire Total Score for Adult Participants (≥18 Years of Age) in the Randomized Population at Week 25	29.95 units on a scale Standard Deviation 13.56	24.04 units on a scale Standard Deviation 15.26	21.39 units on a scale Standard Deviation 12.64	—	—	—

SECONDARY outcome

Timeframe: Baseline, Week 25

Population: Participants randomized to Arms A, B, and C. The number analyzed represents participants who provided responses at Baseline and Week 25.

EQ-5D-5L is a standardized, participant-rated questionnaire to assess health-related quality of life. The EQ-5D-5L includes 2 components: the EQ-5D-5L health state profile (descriptive system) and the EQ-5D-5L VAS. The VAS is designed to rate the participant's current health state on a scale from 0 to 100, where 0 represents the worst imaginable health state and 100 represents the best imaginable health state. The means were derived via an analysis of covariance (ANCOVA) model and have been adjusted for the following co-variates: baseline score, treatment group, and treatment by baseline interaction term.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=14 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=34 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=29 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
European Quality of Life 5-Dimensions-5 Levels (EQ-5D-5L) Questionnaire Visual Analogue Scale (VAS) Score in the Randomized Population at Week 25	72.57 units on a scale Standard Deviation 8.20	76.61 units on a scale Standard Deviation 20.99	81.72 units on a scale Standard Deviation 15.55	—	—	—

SECONDARY outcome

Timeframe: Baseline, Week 25

Population: Participants randomized to Arms A, B, and C. The number analyzed represents participants who provided responses at Baseline and Week 25.

EQ-5D-5L is a standardized, participant-rated questionnaire to assess health-related quality of life. The EQ-5D-5L includes 2 components: the EQ-5D-5L health state profile (descriptive system) and the EQ-5D-5L VAS. The EQ-5D-5L health state profile is designed to record the participant's current health state in 5 domains: mobility, selfcare, usual activities, pain/discomfort, and anxiety/depression. Responses from the five domains are used to calculate a single index utility score on a scale of 0 to 1, with higher scores reflective of better quality of life. The means were derived via an analysis of covariance (ANCOVA) model and have been adjusted for the following co-variates: baseline score, treatment group, and treatment by baseline interaction term.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=14 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=34 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=29 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
EQ-5D-5L Questionnaire Index Utility Score in the Randomized Population at Week 25	0.63 units on a scale Standard Deviation 0.20	0.76 units on a scale Standard Deviation 0.24	0.76 units on a scale Standard Deviation 0.18	—	—	—

SECONDARY outcome

Timeframe: Week 25

Population: The pre-specified efficacy objective was the comparison of Haemo-QoL-SF scores at Week 25 in adolescents who were previously on episodic treatment (i.e., randomized to Arms A, B, or C). Because there was a total of just one adolescent randomized to this study (in Arm C), statistical analyses could not be performed and no data is reported.

The Haemo-QoL-SF contains 35 items, which cover nine domains considered relevant for the children's health-related quality of life (physical health, feelings, view of yourself, family, friends, other people, sports and school, dealing with hemophilia and treatment). Items are rated with five respective response options: never, seldom, sometimes, often, and always. Haemo-QoL-SF total score range from 0 to 100, where lower scores reflect better health-related quality of life.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From Baseline to at least 24 weeks (median [min-max] safety periods for Arm C (Control): 24.00 [14.4-25.0] weeks; Arm A: 30.00 [21.4-49.6] weeks; Arm B: 31.29 [24.4-50.6] weeks; Arm C (Emi): 7.57 [0.3-26.3] weeks; Arm D: 33.71 [18.4-49.6] weeks)

Population: All participants in Arms A, B, and D who received at least one dose of emicizumab and all participants in Arm C (Control) who started the no prophylaxis study period. Participants in Arm C (Emi) are those from Arm C who switched after 24 weeks no prophylaxis to receive emicizumab prophylaxis (2 were excluded who did not switch at the time of analysis).

The percentage of participants experiencing at least one adverse event, including all non-serious and serious adverse events, is reported here. At the clinical cut-off date for primary analysis (15 Sep 2017), data was collected over a period of at least 24 weeks.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=18 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=16 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Percentage of Participants With at Least One Adverse Event During the First 24 Weeks of the Study, Primary Analysis	33.3 percentage of participants	94.4 percentage of participants	85.7 percentage of participants	50.0 percentage of participants	87.3 percentage of participants	—

SECONDARY outcome

The World Health Organization (WHO) toxicity grading scale will be used for assessing adverse event severity. For adverse events that are not specifically listed in the WHO toxicity grading scale, a grade 3 adverse event is defined as: severe, marked limitation in activity, some assistance usually required, medical intervention or therapy required, hospitalization possible; and a grade 4 adverse event is defined as: life-threatening, extreme limitation in activity, significant assistance required, significant medical intervention or therapy required, hospitalization or hospice care probable. At the clinical cut-off date for primary analysis (15 Sep 2017), data was collected over a period of at least 24 weeks.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=18 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=16 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Percentage of Participants With at Least One Grade ≥3 Adverse Event During the First 24 Weeks of the Study, Primary Analysis	5.6 percentage of participants	8.3 percentage of participants	11.4 percentage of participants	0 percentage of participants	9.3 percentage of participants	—

SECONDARY outcome

At the clinical cut-off date for primary analysis (15 Sep 2017), data was collected over a period of at least 24 weeks.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=18 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=16 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Percentage of Participants With at Least One Adverse Event Leading to Withdrawal From Treatment During the First 24 Weeks of the Study, Primary Analysis	0 percentage of participants	0 percentage of participants	2.9 percentage of participants	0 percentage of participants	0 percentage of participants	—

SECONDARY outcome

The percentage of participants with adverse events of changes from baseline in vital signs is reported here. Vital signs measurements consisted of heart and respiratory rate, temperature, and systolic and diastolic blood pressures, with an abnormal vital sign value being outside of the normal range. An abnormal vital sign result is reported as an adverse event if it meets any of the following criteria: is accompanied by clinical symptoms; results in a change in study treatment (e.g., dosage modification, treatment interruption or discontinuation); results in a medical intervention or a change in concomitant therapy; or is clinically significant in the investigator's judgment. At the clinical cut-off date for primary analysis (15 Sep 2017), data was collected over a period of at least 24 weeks.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=18 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=16 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Percentage of Participants With at Least One Adverse Event of Changes From Baseline in Vital Signs During the First 24 Weeks of the Study, Primary Analysis	0 percentage of participants	0 percentage of participants	0 percentage of participants	0 percentage of participants	0 percentage of participants	—

SECONDARY outcome

Post-baseline physical examination abnormalities that were not present at baseline or worsened were reported as adverse events. At the clinical cut-off date for primary analysis (15 Sep 2017), data was collected over a period of at least 24 weeks.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=18 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=16 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Percentage of Participants With at Least One Adverse Event of Changes From Baseline in Physical Examination Findings During the First 24 Weeks of the Study, Primary Analysis	0 percentage of participants	0 percentage of participants	0 percentage of participants	0 percentage of participants	0 percentage of participants	—

SECONDARY outcome

The percentage of participants with adverse events of abnormal laboratory values is reported here. An abnormal laboratory value is defined as a laboratory test result outside of the normal range for hematology or serum chemistries. It is reported as an adverse event if it meets any of the following criteria: is accompanied by clinical symptoms; results in a change in study treatment (e.g., dosage modification, treatment interruption or discontinuation); results in a medical intervention or a change in concomitant therapy; or is clinically significant in the investigator's judgment. At the clinical cut-off date for primary analysis (15 Sep 2017), data was collected over a period of at least 24 weeks.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=18 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=16 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Percentage of Participants With at Least One Adverse Event of Abnormal Laboratory Values During the First 24 Weeks of the Study, Primary Analysis	0 percentage of participants	5.6 percentage of participants	17.1 percentage of participants	6.3 percentage of participants	4.8 percentage of participants	—

SECONDARY outcome

Local adverse events that occurred within 24 hours after study drug administration and, in the investigator's opinion, were judged to be related to study drug injection, were captured as an "injection-site reaction" on the Adverse Event electronic Case Report Form (eCRF). An injection-related reaction that was localized was marked as a "local injection-site reaction." At the clinical cut-off date for primary analysis (15 Sep 2017), data was collected over a period of at least 24 weeks.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=18 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=16 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Percentage of Participants With at Least One Local Injection-Site Reaction During the First 24 Weeks of the Study, Primary Analysis	0 percentage of participants	25.0 percentage of participants	20.0 percentage of participants	12.5 percentage of participants	33.3 percentage of participants	—

SECONDARY outcome

At the clinical cut-off date for primary analysis (15 Sep 2017), data was collected over a period of approximately 1 year.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=18 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=16 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Percentage of Participants With at Least One Thromboembolic Event During the First 24 Weeks of the Study, Primary Analysis	0 percentage of participants	0 percentage of participants	0 percentage of participants	0 percentage of participants	0 percentage of participants	—

SECONDARY outcome

At the clinical cut-off date for primary analysis (15 Sep 2017), data was collected over a period of at least 24 weeks.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=18 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=16 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Percentage of Participants With at Least One Thrombotic Microangiopathy During the First 24 Weeks of the Study, Primary Analysis	0 percentage of participants	0 percentage of participants	0 percentage of participants	0 percentage of participants	0 percentage of participants	—

SECONDARY outcome

At the clinical cut-off date for primary analysis (15 Sep 2017), data was collected over a period of at least 24 weeks.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=18 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=16 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Percentage of Participants With at Least One Systemic Hypersensitivity, Anaphylaxis, or Anaphylactoid Reaction During the First 24 Weeks of the Study, Primary Analysis	0 percentage of participants	0 percentage of participants	0 percentage of participants	0 percentage of participants	0 percentage of participants	—

SECONDARY outcome

Timeframe: From start of emicizumab treatment to study completion, dose up-titration, or change of dosing regimen (median [min-max] efficacy period for all emicizumab participants: 228.14 [7.3-288.3] weeks)

Population: All Emicizumab Participants, which includes all participants who received emicizumab on the study. For Arm C (Emi), it only includes participants who crossed over to receive prophylactic treatment with emicizumab after first completing 24 weeks of no prophylaxis on study (1 participant was excluded because they were lost to follow-up before Week 24 and did not receive emicizumab).

Investigators sought information on adverse events (AEs) at each contact with participants. The WHO toxicity grading scale was used for assessing AE severity (i.e., intensity of an AE); any AEs not specifically listed in the WHO toxicity grading scale were assessed for severity according to the following grades: Grade 1 is mild; Grade 2 is moderate, Grade 3 is severe; Grade 4 is life-threatening; and Grade 5 is death. Regardless of severity, some AEs may have also met seriousness criteria. The terms "severe" and "serious" are not synonymous; severity and seriousness were independently assessed for each AE. For participants whose emicizumab dose was up-titrated and those who opted for a change in dosing regimen (after implementation of protocol v4), only AEs that occurred before either one of those events are included. Hypersens.= hypersensitivity; Mod. = modification

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=17 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=151 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Safety Summary of the Percentage of Emicizumab-Treated Participants With at Least One Adverse Event During the Study Any Adverse Event (AE)	100.0 percentage of participants	97.1 percentage of participants	88.2 percentage of participants	100.0 percentage of participants	98.0 percentage of participants	—
Safety Summary of the Percentage of Emicizumab-Treated Participants With at Least One Adverse Event During the Study AE with Fatal Outcome	0.0 percentage of participants	0.0 percentage of participants	0.0 percentage of participants	0.0 percentage of participants	0.0 percentage of participants	—
Safety Summary of the Percentage of Emicizumab-Treated Participants With at Least One Adverse Event During the Study Serious AE	27.8 percentage of participants	22.9 percentage of participants	5.9 percentage of participants	25.4 percentage of participants	23.2 percentage of participants	—
Safety Summary of the Percentage of Emicizumab-Treated Participants With at Least One Adverse Event During the Study AE Leading to Withdrawal from Treatment	0.0 percentage of participants	2.9 percentage of participants	0.0 percentage of participants	0.0 percentage of participants	0.7 percentage of participants	—
Safety Summary of the Percentage of Emicizumab-Treated Participants With at Least One Adverse Event During the Study AE Leading to Dose Mod./Interruption	2.8 percentage of participants	0.0 percentage of participants	0.0 percentage of participants	1.6 percentage of participants	1.3 percentage of participants	—
Safety Summary of the Percentage of Emicizumab-Treated Participants With at Least One Adverse Event During the Study Grade ≥3 AE	36.1 percentage of participants	28.6 percentage of participants	5.9 percentage of participants	20.6 percentage of participants	24.5 percentage of participants	—
Safety Summary of the Percentage of Emicizumab-Treated Participants With at Least One Adverse Event During the Study Related AE	30.6 percentage of participants	34.3 percentage of participants	23.5 percentage of participants	47.6 percentage of participants	37.7 percentage of participants	—
Safety Summary of the Percentage of Emicizumab-Treated Participants With at Least One Adverse Event During the Study Local Injection Site Reaction	27.8 percentage of participants	22.9 percentage of participants	23.5 percentage of participants	39.7 percentage of participants	31.1 percentage of participants	—
Safety Summary of the Percentage of Emicizumab-Treated Participants With at Least One Adverse Event During the Study Systemic Hypersens./Anaphylac(tic/toid) Reaction	0.0 percentage of participants	0.0 percentage of participants	0.0 percentage of participants	0.0 percentage of participants	0.0 percentage of participants	—
Safety Summary of the Percentage of Emicizumab-Treated Participants With at Least One Adverse Event During the Study Thromboembolic Event (TE)	0.0 percentage of participants	2.9 percentage of participants	0.0 percentage of participants	1.6 percentage of participants	1.3 percentage of participants	—
Safety Summary of the Percentage of Emicizumab-Treated Participants With at Least One Adverse Event During the Study Thrombotic Microangiopathy (TMA)	0.0 percentage of participants	0.0 percentage of participants	0.0 percentage of participants	0.0 percentage of participants	0.0 percentage of participants	—

SECONDARY outcome

Population: All Emicizumab Participants, which includes all participants who received emicizumab on the study. For Arm C, it only includes participants who crossed over to receive prophylactic treatment with emicizumab after first completing 24 weeks of no prophylaxis on study.

The number of bleeds over the efficacy period was assessed as an ABR using a negative binomial (NB) regression model, which accounts for different follow-up times. Treated bleeds: a bleed for which coagulation factors were administered. All bleeds included both treated and non-treated bleeds. Treated spontaneous bleeds: treated bleeds with no known contributing factor (e.g., trauma, surgery). Treated joint bleeds: treated bleeds in a joint associated with unusual sensation (aura) in a joint, in combination with another symptom: swelling/warmth, pain/decreased range of motion (RoM), or difficulty moving the joint. Treated target joint bleeds: treated joint bleeds in a target joint, defined as a joint in which greater than or equal to (≥) 3 treated joint bleeds occurred during the last 24 weeks prior to study entry. For all types of bleeds: the 72-hour rule was implemented, and bleeds due to surgery/procedure and bleeds after up-titration or change of dosing regimen were excluded.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=17 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=151 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Long-Term Efficacy of Emicizumab: Model-Based Annualized Bleeding Rates (ABR) for Treated Bleeds, All Bleeds, Treated Spontaneous Bleeds, Treated Joint Bleeds, and Treated Target Joint Bleeds, All Emicizumab Participants Treated Bleeds	0.8 bleeds per year Interval 0.48 to 1.29	0.7 bleeds per year Interval 0.4 to 1.08	1.2 bleeds per year Interval 0.47 to 3.19	1.5 bleeds per year Interval 1.02 to 2.34	1.2 bleeds per year Interval 0.92 to 1.56	—
Long-Term Efficacy of Emicizumab: Model-Based Annualized Bleeding Rates (ABR) for Treated Bleeds, All Bleeds, Treated Spontaneous Bleeds, Treated Joint Bleeds, and Treated Target Joint Bleeds, All Emicizumab Participants All Bleeds	1.1 bleeds per year Interval 0.72 to 1.66	1.1 bleeds per year Interval 0.73 to 1.73	2.2 bleeds per year Interval 1.16 to 4.15	2.4 bleeds per year Interval 1.68 to 3.43	1.8 bleeds per year Interval 1.46 to 2.29	—
Long-Term Efficacy of Emicizumab: Model-Based Annualized Bleeding Rates (ABR) for Treated Bleeds, All Bleeds, Treated Spontaneous Bleeds, Treated Joint Bleeds, and Treated Target Joint Bleeds, All Emicizumab Participants Treated Spontaneous Bleeds	0.5 bleeds per year Interval 0.23 to 1.03	0.2 bleeds per year Interval 0.1 to 0.45	0.4 bleeds per year Interval 0.12 to 1.35	0.5 bleeds per year Interval 0.3 to 0.78	0.4 bleeds per year Interval 0.29 to 0.58	—
Long-Term Efficacy of Emicizumab: Model-Based Annualized Bleeding Rates (ABR) for Treated Bleeds, All Bleeds, Treated Spontaneous Bleeds, Treated Joint Bleeds, and Treated Target Joint Bleeds, All Emicizumab Participants Treated Joint Bleeds	0.4 bleeds per year Interval 0.24 to 0.73	0.4 bleeds per year Interval 0.21 to 0.68	0.7 bleeds per year Interval 0.25 to 1.66	1.0 bleeds per year Interval 0.6 to 1.76	0.7 bleeds per year Interval 0.53 to 1.0	—
Long-Term Efficacy of Emicizumab: Model-Based Annualized Bleeding Rates (ABR) for Treated Bleeds, All Bleeds, Treated Spontaneous Bleeds, Treated Joint Bleeds, and Treated Target Joint Bleeds, All Emicizumab Participants Treated Target Joint Bleeds	0.2 bleeds per year Interval 0.11 to 0.43	0.2 bleeds per year Interval 0.08 to 0.39	0.4 bleeds per year Interval 0.13 to 1.31	0.6 bleeds per year Interval 0.26 to 1.42	0.4 bleeds per year Interval 0.29 to 0.66	—

SECONDARY outcome

The number of bleeds over the efficacy period was calculated as: ABR = (number of bleeds/number of days during the efficacy period) x 365.25. Treated bleeds: a bleed for which coagulation factors were administered. All bleeds included both treated and non-treated bleeds. Treated spontaneous bleeds: treated bleeds with no known contributing factor (e.g., trauma, surgery). Treated joint bleeds: treated bleeds in a joint associated with unusual sensation (aura) in a joint, in combination with another symptom: swelling/warmth, pain/decreased range of motion (RoM), or difficulty moving the joint. Treated target joint bleeds: treated joint bleeds in a target joint, defined as a joint in which greater than or equal to (≥) 3 treated joint bleeds occurred during the last 24 weeks prior to study entry. For all types of bleeds: the 72-hour rule was implemented, and bleeds due to surgery/procedure and bleeds after up-titration or change of dosing regimen were excluded.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=17 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=151 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds, All Bleeds, Treated Spontaneous Bleeds, Treated Joint Bleeds, and Treated Target Joint Bleeds, All Emicizumab Participants Treated Bleeds	1.2 bleeds per year Interval 0.04 to 5.83	0.8 bleeds per year Interval 0.01 to 5.23	1.2 bleeds per year Interval 0.05 to 5.95	1.7 bleeds per year Interval 0.15 to 6.69	1.3 bleeds per year Interval 0.07 to 6.07	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds, All Bleeds, Treated Spontaneous Bleeds, Treated Joint Bleeds, and Treated Target Joint Bleeds, All Emicizumab Participants All Bleeds	1.4 bleeds per year Interval 0.09 to 6.29	1.3 bleeds per year Interval 0.07 to 6.1	2.2 bleeds per year Interval 0.32 to 7.58	2.6 bleeds per year Interval 0.45 to 8.15	2.0 bleeds per year Interval 0.23 to 7.19	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds, All Bleeds, Treated Spontaneous Bleeds, Treated Joint Bleeds, and Treated Target Joint Bleeds, All Emicizumab Participants Treated Spontaneous Bleeds	0.7 bleeds per year Interval 0.0 to 4.97	0.3 bleeds per year Interval 0.0 to 4.22	0.4 bleeds per year Interval 0.0 to 4.48	0.6 bleeds per year Interval 0.0 to 4.81	0.5 bleeds per year Interval 0.0 to 4.68	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds, All Bleeds, Treated Spontaneous Bleeds, Treated Joint Bleeds, and Treated Target Joint Bleeds, All Emicizumab Participants Treated Joint Bleeds	0.6 bleeds per year Interval 0.0 to 4.94	0.5 bleeds per year Interval 0.0 to 4.64	0.6 bleeds per year Interval 0.0 to 4.95	1.1 bleeds per year Interval 0.04 to 5.78	0.8 bleeds per year Interval 0.01 to 5.23	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds, All Bleeds, Treated Spontaneous Bleeds, Treated Joint Bleeds, and Treated Target Joint Bleeds, All Emicizumab Participants Treated Target Joint Bleeds	0.4 bleeds per year Interval 0.0 to 4.54	0.3 bleeds per year Interval 0.0 to 4.28	0.4 bleeds per year Interval 0.0 to 4.5	0.6 bleeds per year Interval 0.0 to 4.92	0.5 bleeds per year Interval 0.0 to 4.64	—

SECONDARY outcome

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=17 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=151 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds, All Bleeds, Treated Spontaneous Bleeds, Treated Joint Bleeds, and Treated Target Joint Bleeds, All Emicizumab Participants Treated Bleeds	0.4 bleeds per year Interval 0.0 to 1.28	0.4 bleeds per year Interval 0.0 to 1.06	0.0 bleeds per year Interval 0.0 to 2.48	0.5 bleeds per year Interval 0.0 to 1.07	0.4 bleeds per year Interval 0.0 to 1.15	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds, All Bleeds, Treated Spontaneous Bleeds, Treated Joint Bleeds, and Treated Target Joint Bleeds, All Emicizumab Participants All Bleeds	0.5 bleeds per year Interval 0.09 to 1.77	0.8 bleeds per year Interval 0.23 to 1.92	1.6 bleeds per year Interval 0.2 to 3.8	1.0 bleeds per year Interval 0.38 to 2.7	1.0 bleeds per year Interval 0.19 to 2.37	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds, All Bleeds, Treated Spontaneous Bleeds, Treated Joint Bleeds, and Treated Target Joint Bleeds, All Emicizumab Participants Treated Spontaneous Bleeds	0.0 bleeds per year Interval 0.0 to 0.51	0.0 bleeds per year Interval 0.0 to 0.23	0.0 bleeds per year Interval 0.0 to 0.65	0.0 bleeds per year Interval 0.0 to 0.48	0.0 bleeds per year Interval 0.0 to 0.4	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds, All Bleeds, Treated Spontaneous Bleeds, Treated Joint Bleeds, and Treated Target Joint Bleeds, All Emicizumab Participants Treated Joint Bleeds	0.2 bleeds per year Interval 0.0 to 0.89	0.2 bleeds per year Interval 0.0 to 0.49	0.0 bleeds per year Interval 0.0 to 1.09	0.0 bleeds per year Interval 0.0 to 0.59	0.2 bleeds per year Interval 0.0 to 0.72	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds, All Bleeds, Treated Spontaneous Bleeds, Treated Joint Bleeds, and Treated Target Joint Bleeds, All Emicizumab Participants Treated Target Joint Bleeds	0.1 bleeds per year Interval 0.0 to 0.55	0.0 bleeds per year Interval 0.0 to 0.37	0.0 bleeds per year Interval 0.0 to 0.81	0.0 bleeds per year Interval 0.0 to 0.0	0.0 bleeds per year Interval 0.0 to 0.38	—

SECONDARY outcome

Timeframe: 1-12, 13-24, 25-36, 37-48, 49-60, 61-72, 73-84, 85-96, 97-108, 109-120, 121-132, 133-144, 145-156, 157-168, 169-180, 181-192, 193-204, 205-216, 217-228, 229-240, 241-252, 253-264, 265-276, and 277-288 weeks

Population: All Emicizumab Participants, which includes all participants who received emicizumab on the study. The number analyzed includes participants with available data over each interval.

The number of treated bleeds over the efficacy period was calculated as: ABR = (number of bleeds/number of days during the efficacy period) x 365.25. Treated bleeds: a bleed for which coagulation factors were administered. The 72-hour rule was implemented: two bleeds of the same type and at the same anatomical location were counted as one bleed if the second bleed occurred within 72 hours from the last treatment for the first bleed. Bleeds due to surgery/procedure were excluded. For participants with dose up-titration or a change in emicizumab dosing regimen (after implementation of protocol v4), the efficacy period ended the day before the first day on the up-titrated dose or changed dosing regimen.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=151 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 1 to 12 Weeks	1.9 Treated bleeds per year Interval 0.21 to 7.04	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 13 to 24 Weeks	1.9 Treated bleeds per year Interval 0.2 to 6.99	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 25 to 36 Weeks	1.0 Treated bleeds per year Interval 0.02 to 5.57	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 37 to 48 Weeks	0.9 Treated bleeds per year Interval 0.01 to 5.35	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 49 to 60 Weeks	1.0 Treated bleeds per year Interval 0.02 to 5.54	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 61 to 72 Weeks	1.1 Treated bleeds per year Interval 0.04 to 5.72	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 73 to 84 Weeks	0.7 Treated bleeds per year Interval 0.01 to 5.12	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 85 to 96 Weeks	1.1 Treated bleeds per year Interval 0.03 to 5.68	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 97 to 108 Weeks	0.9 Treated bleeds per year Interval 0.01 to 5.32	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 109 to 120 Weeks	0.6 Treated bleeds per year Interval 0.0 to 4.83	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 121 to 132 Weeks	0.5 Treated bleeds per year Interval 0.0 to 4.72	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 133 to 144 Weeks	1.1 Treated bleeds per year Interval 0.03 to 5.68	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 145 to 156 Weeks	1.1 Treated bleeds per year Interval 0.03 to 5.7	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 157 to 168 Weeks	1.1 Treated bleeds per year Interval 0.04 to 5.78	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 169 to 180 Weeks	1.3 Treated bleeds per year Interval 0.06 to 6.05	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 181 to 192 Weeks	1.0 Treated bleeds per year Interval 0.02 to 5.56	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 193 to 204 Weeks	1.6 Treated bleeds per year Interval 0.13 to 6.57	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 205 to 216 Weeks	0.8 Treated bleeds per year Interval 0.01 to 5.15	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 217 to 228 Weeks	0.5 Treated bleeds per year Interval 0.0 to 4.59	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 229 to 240 Weeks	0.8 Treated bleeds per year Interval 0.01 to 5.3	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 241 to 252 Weeks	0.3 Treated bleeds per year Interval 0.0 to 4.21	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 253 to 264 Weeks	0.5 Treated bleeds per year Interval 0.0 to 4.72	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 265 to 276 Weeks	0.2 Treated bleeds per year Interval 0.0 to 4.09	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 277 to 288 Weeks	0.0 Treated bleeds per year Interval to 3.69 The lower limit of the 95% confidence interval could not be calculated because too few events had occurred.	—	—	—	—	—

SECONDARY outcome

Population: All Emicizumab Participants, which includes all participants who received emicizumab on the study. The number analyzed includes participants with available data over each interval.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=151 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 1 to 12 Weeks	0.0 Treated bleeds per year Interval 0.0 to 4.35	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 13 to 24 Weeks	0.0 Treated bleeds per year Interval 0.0 to 2.17	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 25 to 36 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 37 to 48 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 49 to 60 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 61 to 72 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 73 to 84 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 85 to 96 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 97 to 108 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 109 to 120 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 121 to 132 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 133 to 144 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 145 to 156 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 157 to 168 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 169 to 180 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 181 to 192 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 193 to 204 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 205 to 216 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 217 to 228 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 229 to 240 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 241 to 252 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 253 to 264 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 265 to 276 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 277 to 288 Weeks	0.0 Treated bleeds per year Interval 0.0 to 0.0	—	—	—	—	—

SECONDARY outcome

Population: All Emicizumab Participants, which includes all participants who received emicizumab on the study. The number analyzed includes participants with available data over each interval.

The number of all bleeds over the efficacy period was calculated as: ABR = (number of bleeds/number of days during the efficacy period) x 365.25. All bleeds included both treated bleeds (with coagulation factors) and non-treated bleeds. The 72-hour rule was implemented: two bleeds of the same type and at the same anatomical location were counted as one bleed if the second bleed occurred within 72 hours from the last treatment for the first bleed. Bleeds due to surgery/procedure were excluded. For participants with dose up-titration or a change in emicizumab dosing regimen (after implementation of protocol v4), the efficacy period ended the day before the first day on the up-titrated dose or changed dosing regimen.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=151 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 1 to 12 Weeks	3.8 All bleeds per year Interval 0.97 to 9.91	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 13 to 24 Weeks	2.8 All bleeds per year Interval 0.53 to 8.45	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 25 to 36 Weeks	1.8 All bleeds per year Interval 0.17 to 6.83	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 37 to 48 Weeks	1.4 All bleeds per year Interval 0.1 to 6.33	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 49 to 60 Weeks	1.5 All bleeds per year Interval 0.1 to 6.37	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 61 to 72 Weeks	1.6 All bleeds per year Interval 0.14 to 6.66	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 73 to 84 Weeks	1.2 All bleeds per year Interval 0.05 to 5.88	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 85 to 96 Weeks	1.4 All bleeds per year Interval 0.09 to 6.3	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 97 to 108 Weeks	1.3 All bleeds per year Interval 0.06 to 6.02	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 109 to 120 Weeks	0.8 All bleeds per year Interval 0.01 to 5.21	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 121 to 132 Weeks	0.8 All bleeds per year Interval 0.01 to 5.2	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 133 to 144 Weeks	1.2 All bleeds per year Interval 0.04 to 5.84	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 145 to 156 Weeks	1.3 All bleeds per year Interval 0.06 to 6.02	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 157 to 168 Weeks	1.4 All bleeds per year Interval 0.09 to 6.28	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 169 to 180 Weeks	1.7 All bleeds per year Interval 0.15 to 6.72	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 181 to 192 Weeks	1.4 All bleeds per year Interval 0.08 to 6.19	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 193 to 204 Weeks	1.7 All bleeds per year Interval 0.16 to 6.74	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 205 to 216 Weeks	1.1 All bleeds per year Interval 0.04 to 5.72	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 217 to 228 Weeks	0.6 All bleeds per year Interval 0.0 to 4.91	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 229 to 240 Weeks	0.9 All bleeds per year Interval 0.02 to 5.41	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 241 to 252 Weeks	0.4 All bleeds per year Interval 0.0 to 4.47	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 253 to 264 Weeks	0.6 All bleeds per year Interval 0.0 to 4.86	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 265 to 276 Weeks	0.2 All bleeds per year Interval 0.0 to 4.09	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 277 to 288 Weeks	0.0 All bleeds per year Interval to 3.69 The lower limit of the 95% confidence interval could not be calculated because too few events had occurred.	—	—	—	—	—

SECONDARY outcome

Population: All Emicizumab Participants, which includes all participants who received emicizumab on the study. The number analyzed includes participants with available data over each interval.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=151 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 1 to 12 Weeks	0.0 All bleeds per year Interval 0.0 to 4.35	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 13 to 24 Weeks	0.0 All bleeds per year Interval 0.0 to 4.35	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 25 to 36 Weeks	0.0 All bleeds per year Interval 0.0 to 4.35	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 37 to 48 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 49 to 60 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 61 to 72 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 73 to 84 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 85 to 96 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 97 to 108 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 109 to 120 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 121 to 132 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 133 to 144 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 145 to 156 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 157 to 168 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 169 to 180 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 181 to 192 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 193 to 204 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 205 to 216 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 217 to 228 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 229 to 240 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 241 to 252 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 253 to 264 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 265 to 276 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for All Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 277 to 288 Weeks	0.0 All bleeds per year Interval 0.0 to 0.0	—	—	—	—	—

SECONDARY outcome

Population: All Emicizumab Participants, which includes all participants who received emicizumab on the study. The number analyzed includes participants with available data over each interval.

The number of treated spontaneous bleeds over the efficacy period was calculated as: ABR = (number of bleeds/number of days during the efficacy period) x 365.25. Treated spontaneous bleeds were defined as treated (with coagulation factors) bleeds with no known contributing factor (e.g., trauma, surgery). The 72-hour rule was implemented: two bleeds of the same type and at the same anatomical location were counted as one bleed if the second bleed occurred within 72 hours from the last treatment for the first bleed. Bleeds due to surgery/procedure were excluded. For participants with dose up-titration or a change in emicizumab dosing regimen (after implementation of protocol v4), the efficacy period ended the day before the first day on the up-titrated dose or changed dosing regimen.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=151 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 1 to 12 Weeks	0.7 Treated spontaneous bleeds per year Interval 0.0 to 4.98	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 13 to 24 Weeks	0.7 Treated spontaneous bleeds per year Interval 0.0 to 5.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 25 to 36 Weeks	0.3 Treated spontaneous bleeds per year Interval 0.0 to 4.3	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 37 to 48 Weeks	0.4 Treated spontaneous bleeds per year Interval 0.0 to 4.53	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 49 to 60 Weeks	0.5 Treated spontaneous bleeds per year Interval 0.0 to 4.6	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 61 to 72 Weeks	0.3 Treated spontaneous bleeds per year Interval 0.0 to 4.25	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 73 to 84 Weeks	0.1 Treated spontaneous bleeds per year Interval 0.0 to 3.95	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 85 to 96 Weeks	0.4 Treated spontaneous bleeds per year Interval 0.0 to 4.48	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 97 to 108 Weeks	0.2 Treated spontaneous bleeds per year Interval 0.0 to 4.14	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 109 to 120 Weeks	0.2 Treated spontaneous bleeds per year Interval 0.0 to 4.03	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 121 to 132 Weeks	0.1 Treated spontaneous bleeds per year Interval 0.0 to 3.96	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 133 to 144 Weeks	0.6 Treated spontaneous bleeds per year Interval 0.0 to 4.78	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 145 to 156 Weeks	0.6 Treated spontaneous bleeds per year Interval 0.0 to 4.87	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 157 to 168 Weeks	0.2 Treated spontaneous bleeds per year Interval 0.0 to 4.09	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 169 to 180 Weeks	0.4 Treated spontaneous bleeds per year Interval 0.0 to 4.5	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 181 to 192 Weeks	0.2 Treated spontaneous bleeds per year Interval 0.0 to 4.01	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 193 to 204 Weeks	0.1 Treated spontaneous bleeds per year Interval 0.0 to 3.8	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 205 to 216 Weeks	0.3 Treated spontaneous bleeds per year Interval 0.0 to 4.24	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 217 to 228 Weeks	0.1 Treated spontaneous bleeds per year Interval 0.0 to 3.81	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 229 to 240 Weeks	0.1 Treated spontaneous bleeds per year Interval 0.0 to 3.94	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 241 to 252 Weeks	0.1 Treated spontaneous bleeds per year Interval 0.0 to 3.82	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 253 to 264 Weeks	0.3 Treated spontaneous bleeds per year Interval 0.0 to 4.29	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 265 to 276 Weeks	0.2 Treated spontaneous bleeds per year Interval 0.0 to 4.09	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Mean Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 277 to 288 Weeks	0.0 Treated spontaneous bleeds per year Interval to 3.69 The lower limit of the 95% confidence interval could not be calculated because too few events had occurred.	—	—	—	—	—

SECONDARY outcome

Population: All Emicizumab Participants, which includes all participants who received emicizumab on the study. The number analyzed includes participants with available data over each interval.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=151 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 1 to 12 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 13 to 24 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 25 to 36 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 37 to 48 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 49 to 60 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 61 to 72 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 73 to 84 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 85 to 96 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 97 to 108 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 109 to 120 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 121 to 132 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 133 to 144 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 145 to 156 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 157 to 168 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 169 to 180 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 181 to 192 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 193 to 204 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 205 to 216 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 217 to 228 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 229 to 240 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 241 to 252 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 253 to 264 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 265 to 276 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—
Long-Term Efficacy of Emicizumab: Median Calculated Annualized Bleeding Rates (ABR) for Treated Spontaneous Bleeds Per 12-Week Intervals Over Time, All Emicizumab Participants 277 to 288 Weeks	0.0 Treated spontaneous bleeds per year Interval 0.0 to 0.0	—	—	—	—	—

SECONDARY outcome

Timeframe: From Baseline to discontinuation from study (median [min-max] observation period for all emicizumab participants: 262.3 [14.4-288.3] weeks)

Population: The All Emicizumab Population includes all participants in Arms A, B, C (Emi), and D treated with emicizumab; 1 was excluded from Arm C (Emi) (lost to follow-up before Week 24 and had not switched to emicizumab).

A validated enzyme-linked immunosorbent assay (ELISA) method was used to analyze the levels of anti-drug antibodies (ADAs) against emicizumab in plasma. A sample was considered positive for anti-emicizumab antibodies if the test result reached or exceeded a pre-determined threshold. 'Total ADA Positive' is the sum of all subjects who tested positive for ADA in the 2 following categories: 'ADA Positive (Treatment Boosted)', those who are pre-dose ADA positive and have a ≥4-fold increase in post-dose ADA levels compared to baseline measurement; and 'ADA Positive (Treatment Induced)', those who are pre-dose ADA negative or missing data and who have at least one post-dose ADA positive sample.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=17 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=151 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Percentage of Participants With Anti-Emicizumab Antibodies at Any Time Post-Baseline During the Study Total ADA Positive (Boosted+Induced)	8.3 percentage of participants	5.7 percentage of participants	0.0 percentage of participants	1.6 percentage of participants	4.0 percentage of participants	—
Percentage of Participants With Anti-Emicizumab Antibodies at Any Time Post-Baseline During the Study ADA Positive (Treatment Boosted)	0.0 percentage of participants	2.9 percentage of participants	0.0 percentage of participants	0.0 percentage of participants	0.7 percentage of participants	—
Percentage of Participants With Anti-Emicizumab Antibodies at Any Time Post-Baseline During the Study ADA Positive (Treatment Induced)	8.3 percentage of participants	2.9 percentage of participants	0.0 percentage of participants	1.6 percentage of participants	3.3 percentage of participants	—

SECONDARY outcome

Timeframe: From Baseline to discontinuation from study (median [min-max] observation period for all emicizumab participants: 262.3 [14.4-288.3] weeks)

Levels of anti-FVIII antibodies (inhibitors) were analyzed using a validated FVIII activity assay. A participant was considered to have developed de novo FVIII inhibitors if the inhibitor levels detected in a post-baseline sample reached or exceeded a pre-determined threshold.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=17 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=151 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Percentage of Participants With De Novo Development of Factor VIII (FVIII) Inhibitors	0.0 percentage of participants	0.0 percentage of participants	0.0 percentage of participants	0.0 percentage of participants	0.0 percentage of participants	—

SECONDARY outcome

Timeframe: Predose at Weeks 1, 2, 3, 4, 5, 7, 9, 13, 17, 21, 25, 33, 41, 49, 61, 73, 85, 97, 109, 121, 133, 145, 157, 169, 181, 193, 205, 217, 229, 241, 253, 265, and 277

Population: The Pharmacokinetics (PK) Population includes all participants in Arms A, B, C (Emi), and D treated with emicizumab who had at least one post-dose emicizumab concentration result; 1 was excluded from Arm C (Emi) (lost to follow-up before Week 24 and had not switched to emicizumab). Number analyzed represents participants per study arm with available samples at each specified timepoint.

Trough plasma concentrations of emicizumab were analyzed using a validated Enzyme Linked Immunosorbent Assay (ELISA). The lower limit of quantification (LLOQ) was 100 nanograms per milliliter (ng/mL). Because participants in Arm C (Control) switched from no prophylaxis to start receiving emicizumab prophylaxis after Week 24, the timepoints for Arm C (Emi) are expressed relative to first emicizumab dose.

Outcome measures

Outcome measures
Measure	Arm C (Control): No Prophylaxis n=36 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=35 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=17 Participants Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=99 Participants Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arms B and C (Emi): Emicizumab 3 mg/kg Q2W n=52 Participants This analysis set is a combination of all emicizumab-treated participants from Arms B and C (Emi) who received the same emicizumab prophylaxis dosing regimen at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by 3 mg/kg emicizumab SC once every 2 weeks (Q2W) until discontinuation from the study.
Trough Plasma Concentration (Ctrough) of Emicizumab Week 61	55.3 micrograms per milliliter (μg/mL) Standard Deviation 21.4	52.0 micrograms per milliliter (μg/mL) Standard Deviation 21.1	52.5 micrograms per milliliter (μg/mL) Standard Deviation 19.8	61.1 micrograms per milliliter (μg/mL) Standard Deviation 22.5	59.1 micrograms per milliliter (μg/mL) Standard Deviation 22.1	52.2 micrograms per milliliter (μg/mL) Standard Deviation 20.5
Trough Plasma Concentration (Ctrough) of Emicizumab Week 73	54.4 micrograms per milliliter (μg/mL) Standard Deviation 21.5	51.6 micrograms per milliliter (μg/mL) Standard Deviation 21.3	47.8 micrograms per milliliter (μg/mL) Standard Deviation 18.4	58.5 micrograms per milliliter (μg/mL) Standard Deviation 19.2	57.1 micrograms per milliliter (μg/mL) Standard Deviation 20.0	50.4 micrograms per milliliter (μg/mL) Standard Deviation 20.3
Trough Plasma Concentration (Ctrough) of Emicizumab Week 85	48.8 micrograms per milliliter (μg/mL) Standard Deviation 17.4	46.4 micrograms per milliliter (μg/mL) Standard Deviation 20.4	47.7 micrograms per milliliter (μg/mL) Standard Deviation 17.9	56.7 micrograms per milliliter (μg/mL) Standard Deviation 18.5	53.8 micrograms per milliliter (μg/mL) Standard Deviation 18.5	46.8 micrograms per milliliter (μg/mL) Standard Deviation 19.5
Trough Plasma Concentration (Ctrough) of Emicizumab Week 97	52.6 micrograms per milliliter (μg/mL) Standard Deviation 20.0	50.9 micrograms per milliliter (μg/mL) Standard Deviation 21.0	51.7 micrograms per milliliter (μg/mL) Standard Deviation 28.3	58.5 micrograms per milliliter (μg/mL) Standard Deviation 18.7	56.3 micrograms per milliliter (μg/mL) Standard Deviation 19.3	51.1 micrograms per milliliter (μg/mL) Standard Deviation 22.9
Trough Plasma Concentration (Ctrough) of Emicizumab Week 109	53.9 micrograms per milliliter (μg/mL) Standard Deviation 19.2	52.3 micrograms per milliliter (μg/mL) Standard Deviation 19.5	46.4 micrograms per milliliter (μg/mL) Standard Deviation 27.0	59.0 micrograms per milliliter (μg/mL) Standard Deviation 19.1	57.0 micrograms per milliliter (μg/mL) Standard Deviation 19.1	50.5 micrograms per milliliter (μg/mL) Standard Deviation 21.7
Trough Plasma Concentration (Ctrough) of Emicizumab Week 121	58.8 micrograms per milliliter (μg/mL) Standard Deviation 21.1	55.0 micrograms per milliliter (μg/mL) Standard Deviation 22.0	50.0 micrograms per milliliter (μg/mL) Standard Deviation 25.2	57.1 micrograms per milliliter (μg/mL) Standard Deviation 18.2	57.7 micrograms per milliliter (μg/mL) Standard Deviation 19.2	53.5 micrograms per milliliter (μg/mL) Standard Deviation 22.7
Trough Plasma Concentration (Ctrough) of Emicizumab Week 133	55.3 micrograms per milliliter (μg/mL) Standard Deviation 26.0	54.7 micrograms per milliliter (μg/mL) Standard Deviation 18.5	54.6 micrograms per milliliter (μg/mL) Standard Deviation 26.9	59.3 micrograms per milliliter (μg/mL) Standard Deviation 19.2	57.7 micrograms per milliliter (μg/mL) Standard Deviation 22.1	54.7 micrograms per milliliter (μg/mL) Standard Deviation 20.9
Trough Plasma Concentration (Ctrough) of Emicizumab Week 145	54.1 micrograms per milliliter (μg/mL) Standard Deviation 23.7	51.3 micrograms per milliliter (μg/mL) Standard Deviation 17.7	44.8 micrograms per milliliter (μg/mL) Standard Deviation 11.6	55.7 micrograms per milliliter (μg/mL) Standard Deviation 20.4	55.0 micrograms per milliliter (μg/mL) Standard Deviation 21.6	49.9 micrograms per milliliter (μg/mL) Standard Deviation 16.6
Trough Plasma Concentration (Ctrough) of Emicizumab Week 157	57.6 micrograms per milliliter (μg/mL) Standard Deviation 27.8	52.2 micrograms per milliliter (μg/mL) Standard Deviation 21.4	46.8 micrograms per milliliter (μg/mL) Standard Deviation 24.0	55.9 micrograms per milliliter (μg/mL) Standard Deviation 23.7	56.6 micrograms per milliliter (μg/mL) Standard Deviation 25.1	50.6 micrograms per milliliter (μg/mL) Standard Deviation 21.9
Trough Plasma Concentration (Ctrough) of Emicizumab Week 1	NA micrograms per milliliter (μg/mL) Standard Deviation NA No results available because the samples were below the limit of quantification (BLQ).	NA micrograms per milliliter (μg/mL) Standard Deviation NA No results available because the samples were below the limit of quantification (BLQ).	NA micrograms per milliliter (μg/mL) Standard Deviation NA No results available because the samples were below the limit of quantification (BLQ).	NA micrograms per milliliter (μg/mL) Standard Deviation NA No results available because the samples were below the limit of quantification (BLQ).	NA micrograms per milliliter (μg/mL) Standard Deviation NA No results available because the samples were below the limit of quantification (BLQ).	NA micrograms per milliliter (μg/mL) Standard Deviation NA No results available because the samples were below the limit of quantification (BLQ).
Trough Plasma Concentration (Ctrough) of Emicizumab Week 2	16.3 micrograms per milliliter (μg/mL) Standard Deviation 6.1	16.8 micrograms per milliliter (μg/mL) Standard Deviation 5.9	19.6 micrograms per milliliter (μg/mL) Standard Deviation 8.2	17.3 micrograms per milliliter (μg/mL) Standard Deviation 5.4	16.9 micrograms per milliliter (μg/mL) Standard Deviation 5.7	17.7 micrograms per milliliter (μg/mL) Standard Deviation 6.8
Trough Plasma Concentration (Ctrough) of Emicizumab Week 3	29.1 micrograms per milliliter (μg/mL) Standard Deviation 9.3	29.2 micrograms per milliliter (μg/mL) Standard Deviation 6.5	33.0 micrograms per milliliter (μg/mL) Standard Deviation 12.6	30.5 micrograms per milliliter (μg/mL) Standard Deviation 8.7	30.0 micrograms per milliliter (μg/mL) Standard Deviation 8.9	30.5 micrograms per milliliter (μg/mL) Standard Deviation 9.0
Trough Plasma Concentration (Ctrough) of Emicizumab Week 4	41.9 micrograms per milliliter (μg/mL) Standard Deviation 11.8	41.4 micrograms per milliliter (μg/mL) Standard Deviation 9.7	47.9 micrograms per milliliter (μg/mL) Standard Deviation 15.0	42.4 micrograms per milliliter (μg/mL) Standard Deviation 9.4	42.2 micrograms per milliliter (μg/mL) Standard Deviation 10.3	43.6 micrograms per milliliter (μg/mL) Standard Deviation 11.9
Trough Plasma Concentration (Ctrough) of Emicizumab Week 5	48.0 micrograms per milliliter (μg/mL) Standard Deviation 13.7	48.8 micrograms per milliliter (μg/mL) Standard Deviation 12.3	59.6 micrograms per milliliter (μg/mL) Standard Deviation 20.7	54.5 micrograms per milliliter (μg/mL) Standard Deviation 12.5	52.2 micrograms per milliliter (μg/mL) Standard Deviation 13.2	52.4 micrograms per milliliter (μg/mL) Standard Deviation 16.2
Trough Plasma Concentration (Ctrough) of Emicizumab Week 7	47.9 micrograms per milliliter (μg/mL) Standard Deviation 16.1	48.4 micrograms per milliliter (μg/mL) Standard Deviation 11.4	55.2 micrograms per milliliter (μg/mL) Standard Deviation 16.2	52.4 micrograms per milliliter (μg/mL) Standard Deviation 13.3	50.9 micrograms per milliliter (μg/mL) Standard Deviation 14.4	50.7 micrograms per milliliter (μg/mL) Standard Deviation 13.5
Trough Plasma Concentration (Ctrough) of Emicizumab Week 9	49.0 micrograms per milliliter (μg/mL) Standard Deviation 16.4	46.4 micrograms per milliliter (μg/mL) Standard Deviation 14.1	53.1 micrograms per milliliter (μg/mL) Standard Deviation 15.7	55.1 micrograms per milliliter (μg/mL) Standard Deviation 16.1	53.0 micrograms per milliliter (μg/mL) Standard Deviation 16.4	48.7 micrograms per milliliter (μg/mL) Standard Deviation 14.9
Trough Plasma Concentration (Ctrough) of Emicizumab Week 13	48.7 micrograms per milliliter (μg/mL) Standard Deviation 18.3	47.6 micrograms per milliliter (μg/mL) Standard Deviation 16.0	47.9 micrograms per milliliter (μg/mL) Standard Deviation 18.1	55.0 micrograms per milliliter (μg/mL) Standard Deviation 15.9	52.8 micrograms per milliliter (μg/mL) Standard Deviation 16.9	47.7 micrograms per milliliter (μg/mL) Standard Deviation 16.5
Trough Plasma Concentration (Ctrough) of Emicizumab Week 17	54.3 micrograms per milliliter (μg/mL) Standard Deviation 24.0	48.9 micrograms per milliliter (μg/mL) Standard Deviation 17.7	43.4 micrograms per milliliter (μg/mL) Standard Deviation 16.2	55.0 micrograms per milliliter (μg/mL) Standard Deviation 16.5	54.7 micrograms per milliliter (μg/mL) Standard Deviation 19.3	47.0 micrograms per milliliter (μg/mL) Standard Deviation 17.2
Trough Plasma Concentration (Ctrough) of Emicizumab Week 21	50.7 micrograms per milliliter (μg/mL) Standard Deviation 20.2	47.3 micrograms per milliliter (μg/mL) Standard Deviation 15.5	45.6 micrograms per milliliter (μg/mL) Standard Deviation 18.8	55.1 micrograms per milliliter (μg/mL) Standard Deviation 16.2	53.6 micrograms per milliliter (μg/mL) Standard Deviation 17.7	46.7 micrograms per milliliter (μg/mL) Standard Deviation 16.4
Trough Plasma Concentration (Ctrough) of Emicizumab Week 25	50.5 micrograms per milliliter (μg/mL) Standard Deviation 21.7	47.6 micrograms per milliliter (μg/mL) Standard Deviation 18.9	51.8 micrograms per milliliter (μg/mL) Standard Deviation 23.4	54.8 micrograms per milliliter (μg/mL) Standard Deviation 16.8	53.3 micrograms per milliliter (μg/mL) Standard Deviation 18.7	49.0 micrograms per milliliter (μg/mL) Standard Deviation 20.4
Trough Plasma Concentration (Ctrough) of Emicizumab Week 33	56.3 micrograms per milliliter (μg/mL) Standard Deviation 25.3	52.9 micrograms per milliliter (μg/mL) Standard Deviation 22.4	52.0 micrograms per milliliter (μg/mL) Standard Deviation 21.3	59.1 micrograms per milliliter (μg/mL) Standard Deviation 18.5	58.1 micrograms per milliliter (μg/mL) Standard Deviation 20.9	52.6 micrograms per milliliter (μg/mL) Standard Deviation 21.9
Trough Plasma Concentration (Ctrough) of Emicizumab Week 41	54.8 micrograms per milliliter (μg/mL) Standard Deviation 24.2	48.4 micrograms per milliliter (μg/mL) Standard Deviation 18.8	50.7 micrograms per milliliter (μg/mL) Standard Deviation 24.4	59.6 micrograms per milliliter (μg/mL) Standard Deviation 21.4	57.9 micrograms per milliliter (μg/mL) Standard Deviation 22.4	49.2 micrograms per milliliter (μg/mL) Standard Deviation 20.6
Trough Plasma Concentration (Ctrough) of Emicizumab Week 49	55.4 micrograms per milliliter (μg/mL) Standard Deviation 22.9	52.2 micrograms per milliliter (μg/mL) Standard Deviation 20.2	54.3 micrograms per milliliter (μg/mL) Standard Deviation 21.3	60.2 micrograms per milliliter (μg/mL) Standard Deviation 19.9	58.5 micrograms per milliliter (μg/mL) Standard Deviation 21.0	52.9 micrograms per milliliter (μg/mL) Standard Deviation 20.4
Trough Plasma Concentration (Ctrough) of Emicizumab Week 169	53.9 micrograms per milliliter (μg/mL) Standard Deviation 21.8	50.3 micrograms per milliliter (μg/mL) Standard Deviation 19.6	45.8 micrograms per milliliter (μg/mL) Standard Deviation 20.6	56.4 micrograms per milliliter (μg/mL) Standard Deviation 18.0	55.3 micrograms per milliliter (μg/mL) Standard Deviation 19.4	48.8 micrograms per milliliter (μg/mL) Standard Deviation 19.6
Trough Plasma Concentration (Ctrough) of Emicizumab Week 181	59.8 micrograms per milliliter (μg/mL) Standard Deviation 24.8	48.8 micrograms per milliliter (μg/mL) Standard Deviation 22.1	43.5 micrograms per milliliter (μg/mL) Standard Deviation 26.2	57.5 micrograms per milliliter (μg/mL) Standard Deviation 21.3	58.6 micrograms per milliliter (μg/mL) Standard Deviation 22.7	46.5 micrograms per milliliter (μg/mL) Standard Deviation 23.4
Trough Plasma Concentration (Ctrough) of Emicizumab Week 193	53.9 micrograms per milliliter (μg/mL) Standard Deviation 21.0	52.4 micrograms per milliliter (μg/mL) Standard Deviation 24.6	42.1 micrograms per milliliter (μg/mL) Standard Deviation 19.1	60.5 micrograms per milliliter (μg/mL) Standard Deviation 19.6	57.5 micrograms per milliliter (μg/mL) Standard Deviation 20.2	49.5 micrograms per milliliter (μg/mL) Standard Deviation 23.3
Trough Plasma Concentration (Ctrough) of Emicizumab Week 205	53.5 micrograms per milliliter (μg/mL) Standard Deviation 20.8	51.9 micrograms per milliliter (μg/mL) Standard Deviation 22.4	54.2 micrograms per milliliter (μg/mL) Standard Deviation 31.1	58.6 micrograms per milliliter (μg/mL) Standard Deviation 24.1	56.4 micrograms per milliliter (μg/mL) Standard Deviation 22.6	52.6 micrograms per milliliter (μg/mL) Standard Deviation 24.6
Trough Plasma Concentration (Ctrough) of Emicizumab Week 217	54.4 micrograms per milliliter (μg/mL) Standard Deviation 20.8	55.0 micrograms per milliliter (μg/mL) Standard Deviation 20.6	50.8 micrograms per milliliter (μg/mL) Standard Deviation 26.1	60.8 micrograms per milliliter (μg/mL) Standard Deviation 23.2	58.3 micrograms per milliliter (μg/mL) Standard Deviation 22.2	53.6 micrograms per milliliter (μg/mL) Standard Deviation 22.1
Trough Plasma Concentration (Ctrough) of Emicizumab Week 229	54.9 micrograms per milliliter (μg/mL) Standard Deviation 20.9	47.9 micrograms per milliliter (μg/mL) Standard Deviation 18.9	53.5 micrograms per milliliter (μg/mL) Standard Deviation 30.4	54.4 micrograms per milliliter (μg/mL) Standard Deviation 19.3	54.6 micrograms per milliliter (μg/mL) Standard Deviation 19.7	49.8 micrograms per milliliter (μg/mL) Standard Deviation 23.1
Trough Plasma Concentration (Ctrough) of Emicizumab Week 241	51.9 micrograms per milliliter (μg/mL) Standard Deviation 19.3	50.2 micrograms per milliliter (μg/mL) Standard Deviation 16.8	52.0 micrograms per milliliter (μg/mL) Standard Deviation 36.1	60.1 micrograms per milliliter (μg/mL) Standard Deviation 23.3	56.8 micrograms per milliliter (μg/mL) Standard Deviation 21.9	50.6 micrograms per milliliter (μg/mL) Standard Deviation 22.2
Trough Plasma Concentration (Ctrough) of Emicizumab Week 253	58.6 micrograms per milliliter (μg/mL) Standard Deviation 28.7	46.5 micrograms per milliliter (μg/mL) Standard Deviation 17.8	40.3 micrograms per milliliter (μg/mL) Standard Deviation 43.9	58.4 micrograms per milliliter (μg/mL) Standard Deviation 24.7	58.5 micrograms per milliliter (μg/mL) Standard Deviation 26.0	45.2 micrograms per milliliter (μg/mL) Standard Deviation 23.9
Trough Plasma Concentration (Ctrough) of Emicizumab Week 265	58.7 micrograms per milliliter (μg/mL) Standard Deviation 25.8	47.3 micrograms per milliliter (μg/mL) Standard Deviation 14.5	—	60.0 micrograms per milliliter (μg/mL) Standard Deviation 23.9	59.5 micrograms per milliliter (μg/mL) Standard Deviation 24.2	47.3 micrograms per milliliter (μg/mL) Standard Deviation 14.5
Trough Plasma Concentration (Ctrough) of Emicizumab Week 277	71.9 micrograms per milliliter (μg/mL) Standard Deviation 34.2	49.0 micrograms per milliliter (μg/mL) Standard Deviation 16.2	—	61.3 micrograms per milliliter (μg/mL) Standard Deviation 17.2	69.2 micrograms per milliliter (μg/mL) Standard Deviation 30.1	49.0 micrograms per milliliter (μg/mL) Standard Deviation 16.2

Adverse Events

Arm C (Control): No Prophylaxis

Serious events: 1 serious events

Other events: 5 other events

Deaths: 0 deaths

Arm A: Emicizumab 1.5 mg/kg QW

Serious events: 10 serious events

Other events: 35 other events

Deaths: 0 deaths

Arm B: Emicizumab 3 mg/kg Q2W

Serious events: 8 serious events

Other events: 33 other events

Deaths: 0 deaths

Arm C (Emi): Emicizumab 3 mg/kg Q2W (Switch From No Prophylaxis)

Serious events: 1 serious events

Other events: 15 other events

Deaths: 0 deaths

Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis)

Serious events: 16 serious events

Other events: 61 other events

Deaths: 0 deaths

Serious adverse events

Serious adverse events
Measure	Arm C (Control): No Prophylaxis n=18 participants at risk Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=36 participants at risk Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=35 participants at risk Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm C (Emi): Emicizumab 3 mg/kg Q2W (Switch From No Prophylaxis) n=17 participants at risk This arm includes all participants from Arm C who had switched to emicizumab prophylaxis during the entire study after having completed 24 weeks on No Prophylaxis. The data reported was collected only during emicizumab prophylaxis treatment. Emicizumab was administered at a loading dose of 3 mg/kg SC once per week (QW) for the first 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC Q2W. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 participants at risk Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.
Cardiac disorders ACUTE CORONARY SYNDROME	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Cardiac disorders ACUTE MYOCARDIAL INFARCTION	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Cardiac disorders ARRHYTHMIA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Cardiac disorders ATRIAL FLUTTER	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Endocrine disorders HYPERPARATHYROIDISM	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders ANAL HAEMORRHAGE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders FISTULA OF SMALL INTESTINE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders GASTRIC HAEMORRHAGE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders HAEMATEMESIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders HAEMATOCHEZIA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders MALLORY-WEISS SYNDROME	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders MELAENA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders PANCREATITIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders RECTAL HAEMORRHAGE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders RETROPERITONEAL HAEMORRHAGE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders SPLENIC ARTERY ANEURYSM	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders UPPER GASTROINTESTINAL HAEMORRHAGE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
General disorders ASTHENIA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations ABSCESS LIMB	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations APPENDICITIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations ARTHRITIS BACTERIAL	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations GINGIVAL ABSCESS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations INFECTION	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations PYELONEPHRITIS ACUTE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations SUBPERIOSTEAL ABSCESS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations TONSILLITIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations WOUND INFECTION	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications DURAL TEAR	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications FEMORAL NECK FRACTURE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications FEMUR FRACTURE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications MUSCLE RUPTURE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications MUSCLE STRAIN	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications POISONING	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications POST PROCEDURAL HAEMATOMA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications ROAD TRAFFIC ACCIDENT	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications TENDON RUPTURE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Metabolism and nutrition disorders DIABETES MELLITUS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders BACK PAIN	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders GROIN PAIN	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders OSTEOARTHRITIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders RHABDOMYOLYSIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders SYNOVITIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Neoplasms benign, malignant and unspecified (incl cysts and polyps) BONE GIANT CELL TUMOUR BENIGN	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Neoplasms benign, malignant and unspecified (incl cysts and polyps) PAPILLARY THYROID CANCER	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Neoplasms benign, malignant and unspecified (incl cysts and polyps) PARATHYROID TUMOUR BENIGN	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Neoplasms benign, malignant and unspecified (incl cysts and polyps) SALIVARY GLAND NEOPLASM	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Nervous system disorders CEREBRAL HAEMORRHAGE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Nervous system disorders CEREBROSPINAL FLUID LEAKAGE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Nervous system disorders HEADACHE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Nervous system disorders PUTAMEN HAEMORRHAGE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Nervous system disorders SEIZURE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Product Issues DEVICE LOOSENING	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Psychiatric disorders SUICIDAL IDEATION	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Renal and urinary disorders HAEMATURIA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Renal and urinary disorders NEPHROLITHIASIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Renal and urinary disorders RENAL HAEMATOMA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Renal and urinary disorders URETEROLITHIASIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Respiratory, thoracic and mediastinal disorders EPISTAXIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Vascular disorders HAEMATOMA	5.6% 1/18 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Vascular disorders HAEMORRHAGE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.

Other adverse events

Other adverse events
Measure	Arm C (Control): No Prophylaxis n=18 participants at risk Participants who had received episodic treatment with FVIII prior to study entry were randomized to continue episodic FVIII treatment when they started the trial; they were given the opportunity to switch to emicizumab prophylaxis after completing 24 weeks of no prophylaxis. The results for this control arm represent data collected during the first 24 weeks on study while receiving their usual care of episodic treatment with FVIII.	Arm A: Emicizumab 1.5 mg/kg QW n=36 participants at risk Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm B: Emicizumab 3 mg/kg Q2W n=35 participants at risk Participants who had received episodic treatment with FVIII prior to study entry were randomized to receive emicizumab prophylaxis at a dose of 3 milligrams per kilogram (mg/kg) subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC once every 2 weeks (Q2W). Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm C (Emi): Emicizumab 3 mg/kg Q2W (Switch From No Prophylaxis) n=17 participants at risk This arm includes all participants from Arm C who had switched to emicizumab prophylaxis during the entire study after having completed 24 weeks on No Prophylaxis. The data reported was collected only during emicizumab prophylaxis treatment. Emicizumab was administered at a loading dose of 3 mg/kg SC once per week (QW) for the first 4 weeks, followed by maintenance dosing of 3 mg/kg emicizumab SC Q2W. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.	Arm D: Emicizumab 1.5 mg/kg QW (Pre-study FVIII Prophylaxis) n=63 participants at risk Participants who had received FVIII prophylaxis prior to study entry were enrolled to receive emicizumab prophylaxis at a dose of 3 mg/kg subcutaneously (SC) once per week (QW) for 4 weeks, followed by maintenance dosing of 1.5 mg/kg emicizumab SC QW. Upon implementation of protocol version 4 (20-Dec-2019), treatment duration was extended. During this study prolongation, each participant was given the option to choose a preferred emicizumab dosing regimen among those permitted and continue on that dosing regimen until discontinuation from the study.
Metabolism and nutrition disorders HYPERCHOLESTEROLAEMIA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Metabolism and nutrition disorders HYPERURICAEMIA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Congenital, familial and genetic disorders HYDROCELE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Ear and labyrinth disorders TINNITUS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Endocrine disorders HYPOTHYROIDISM	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Eye disorders CATARACT	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders ABDOMINAL PAIN	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	8.3% 3/36 • Number of events 5 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	17.6% 3/17 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	3.2% 2/63 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders ABDOMINAL PAIN UPPER	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	8.6% 3/35 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	6.3% 4/63 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders CONSTIPATION	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	7.9% 5/63 • Number of events 6 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders DENTAL CARIES	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 7 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	4.8% 3/63 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders DIARRHOEA	5.6% 1/18 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.1% 4/36 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	14.3% 5/35 • Number of events 6 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.8% 2/17 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	9.5% 6/63 • Number of events 6 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders DYSPEPSIA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders GASTRITIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders GASTROOESOPHAGEAL REFLUX DISEASE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders LARGE INTESTINE POLYP	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders NAUSEA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.4% 4/35 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.1% 7/63 • Number of events 9 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Gastrointestinal disorders VOMITING	5.6% 1/18 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	4.8% 3/63 • Number of events 5 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
General disorders ASTHENIA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
General disorders INFLUENZA LIKE ILLNESS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	3.2% 2/63 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
General disorders INJECTION SITE REACTION	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	27.8% 10/36 • Number of events 37 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	22.9% 8/35 • Number of events 25 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	23.5% 4/17 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	38.1% 24/63 • Number of events 42 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
General disorders PAIN	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	3.2% 2/63 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
General disorders PYREXIA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.1% 4/36 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	9.5% 6/63 • Number of events 7 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Immune system disorders DRUG HYPERSENSITIVITY	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Immune system disorders HYPERSENSITIVITY	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Immune system disorders SEASONAL ALLERGY	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	3.2% 2/63 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations BACTERIAL INFECTION	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations BODY TINEA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations BRONCHITIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.8% 2/17 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	4.8% 3/63 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations CONJUNCTIVITIS	5.6% 1/18 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations CORONAVIRUS INFECTION	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations COVID-19	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	8.3% 3/36 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.1% 7/63 • Number of events 7 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations DIARRHOEA INFECTIOUS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations EAR INFECTION	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations GASTRIC INFECTION	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations GASTROENTERITIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	8.3% 3/36 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations INFLUENZA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	19.4% 7/36 • Number of events 8 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.4% 4/35 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.8% 2/17 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	14.3% 9/63 • Number of events 10 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations LOCALISED INFECTION	5.6% 1/18 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations LOWER RESPIRATORY TRACT INFECTION	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations NASOPHARYNGITIS	5.6% 1/18 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	25.0% 9/36 • Number of events 16 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	22.9% 8/35 • Number of events 19 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	17.6% 3/17 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	31.7% 20/63 • Number of events 35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations PERIODONTITIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.8% 2/17 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations PHARYNGITIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.1% 4/36 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	4.8% 3/63 • Number of events 10 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations RESPIRATORY TRACT INFECTION	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations RHINITIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations SINUSITIS	5.6% 1/18 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.8% 2/17 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	6.3% 4/63 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations UPPER RESPIRATORY TRACT INFECTION	5.6% 1/18 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	22.2% 8/36 • Number of events 11 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	17.1% 6/35 • Number of events 9 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	17.6% 3/17 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	22.2% 14/63 • Number of events 19 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications ARTHROPOD BITE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 5 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications BACK INJURY	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications BITE	5.6% 1/18 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications CONTUSION	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	8.3% 3/36 • Number of events 15 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.8% 2/17 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	9.5% 6/63 • Number of events 13 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications FALL	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	12.7% 8/63 • Number of events 9 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications JOINT INJURY	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 5 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	7.9% 5/63 • Number of events 9 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications LIGAMENT INJURY	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications LIGAMENT SPRAIN	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	15.9% 10/63 • Number of events 17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications LIMB INJURY	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	8.6% 3/35 • Number of events 5 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	4.8% 3/63 • Number of events 5 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications MUSCLE STRAIN	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	8.3% 3/36 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	3.2% 2/63 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications ROAD TRAFFIC ACCIDENT	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications SKIN LACERATION	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.8% 2/17 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	4.8% 3/63 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications TONGUE INJURY	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications TOOTH FRACTURE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	3.2% 2/63 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Investigations ALANINE AMINOTRANSFERASE INCREASED	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	6.3% 4/63 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Investigations ASPARTATE AMINOTRANSFERASE INCREASED	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	4.8% 3/63 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Investigations BLOOD CREATINE PHOSPHOKINASE INCREASED	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	7.9% 5/63 • Number of events 5 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Investigations BLOOD CREATININE INCREASED	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Investigations BLOOD PRESSURE DIASTOLIC INCREASED	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders ARTHRALGIA	5.6% 1/18 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	44.4% 16/36 • Number of events 41 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	31.4% 11/35 • Number of events 26 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	17.6% 3/17 • Number of events 5 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	39.7% 25/63 • Number of events 78 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders ARTHRITIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders BACK PAIN	5.6% 1/18 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	16.7% 6/36 • Number of events 11 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	8.6% 3/35 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.8% 2/17 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	12.7% 8/63 • Number of events 10 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders GROIN PAIN	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	6.3% 4/63 • Number of events 5 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders HAEMOPHILIC ARTHROPATHY	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders JOINT SWELLING	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	12.7% 8/63 • Number of events 10 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders MUSCLE CONTRACTURE	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	3.2% 2/63 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders MUSCLE SPASMS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	3.2% 2/63 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders MUSCULOSKELETAL STIFFNESS	5.6% 1/18 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders MYALGIA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.1% 4/36 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	9.5% 6/63 • Number of events 7 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders PAIN IN EXTREMITY	5.6% 1/18 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	13.9% 5/36 • Number of events 6 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.4% 4/35 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	9.5% 6/63 • Number of events 7 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders SYNOVITIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.1% 7/63 • Number of events 9 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Neoplasms benign, malignant and unspecified (incl cysts and polyps) PAPILLOMA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Nervous system disorders DIZZINESS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Nervous system disorders HEADACHE	5.6% 1/18 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	19.4% 7/36 • Number of events 13 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	20.0% 7/35 • Number of events 30 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.8% 2/17 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	22.2% 14/63 • Number of events 33 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Nervous system disorders PARAESTHESIA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	4.8% 3/63 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Nervous system disorders SCIATICA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Psychiatric disorders ANXIETY	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.1% 4/36 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	6.3% 4/63 • Number of events 7 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Psychiatric disorders DEPRESSION	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	6.3% 4/63 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Psychiatric disorders INSOMNIA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	3.2% 2/63 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Psychiatric disorders SLEEP DISORDER	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Renal and urinary disorders NEPHROLITHIASIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Reproductive system and breast disorders ERECTILE DYSFUNCTION	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Respiratory, thoracic and mediastinal disorders COUGH	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.1% 4/36 • Number of events 7 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	11.1% 7/63 • Number of events 9 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Respiratory, thoracic and mediastinal disorders NASAL CONGESTION	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	3.2% 2/63 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Respiratory, thoracic and mediastinal disorders OROPHARYNGEAL PAIN	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	9.5% 6/63 • Number of events 12 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Skin and subcutaneous tissue disorders ALOPECIA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Skin and subcutaneous tissue disorders ECZEMA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	4.8% 3/63 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Skin and subcutaneous tissue disorders PRURITUS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.7% 2/35 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	6.3% 4/63 • Number of events 5 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Skin and subcutaneous tissue disorders RASH	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	13.9% 5/36 • Number of events 7 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	14.3% 9/63 • Number of events 9 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Skin and subcutaneous tissue disorders RASH MACULO-PAPULAR	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.9% 1/17 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Vascular disorders HAEMATOMA	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	1.6% 1/63 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Infections and infestations ABSCESS LIMB	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Injury, poisoning and procedural complications SKIN ABRASION	5.6% 1/18 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/36 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.9% 1/35 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	4.8% 3/63 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders TENDONITIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	3.2% 2/63 • Number of events 3 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Musculoskeletal and connective tissue disorders TENOSYNOVITIS	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	5.6% 2/36 • Number of events 2 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/63 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.
Vascular disorders HYPERTENSION	0.00% 0/18 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	2.8% 1/36 • Number of events 1 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/35 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	0.00% 0/17 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.	6.3% 4/63 • Number of events 4 • Total observation time for all participants: From enrollment until study completion (median [min-max] 262.3 [14.4-288.3] weeks); Arm C (Control): From enrollment to 24 weeks on no prophylaxis (median [min-max]: 24.00 [14.4-25.0] weeks) All adverse events (AEs) in emicizumab-treated subjects are reported, including after dose up-titration or change of dosing regimen. AEs in Arm C are reported in 2 groups: Arm C (Control) for the first 24 weeks on no prophylaxis; Arm C (Emi) for those who switched after 24 weeks to receive emicizumab prophylaxis.

Additional Information

Medical Communications

Hoffmann-La Roche

Phone: 800-821-8590

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee The Study being conducted under this Agreement is part of the Overall Study. Investigator is free to publish in reputable journals or to present at professional conferences the results of the Study, but only after the first publication or presentation that involves the Overall Study. The Sponsor may request that Confidential Information be deleted and/or the publication be postponed in order to protect the Sponsor's intellectual property rights.
Publication restrictions are in place

Restriction type: OTHER