Trial Outcomes & Findings for Study to Assess the Efficacy of Baloxavir Marboxil Versus Placebo to Reduce Onward Transmission of Influenza A or B in Households (NCT NCT03969212)

NCT ID: NCT03969212

Last Updated: 2025-07-04

Results Overview

The virological transmission was determined based on Polymerase Chain Reaction Positive (PCR+) influenza test results. The adjusted incidence (cumulative proportion of events by Day 5) rate is reported here. This is defined as percentage of HHCs who tested PCR+ for influenza by Day 5 post IP randomization with virus subtype matching with that of the respective IP, irrespective of being symptomatic or asymptomatic. The adjusted incidence rates presented were estimated using a generalized estimating equations (GEE) approach.

Recruitment status

COMPLETED

Study phase

PHASE3

Target enrollment

4138 participants

Primary outcome timeframe

Baseline (Day 1) to Day 5

Results posted on

2025-07-04

Participant Flow

Participants with acute influenza infection (Index participants \[IPs\]) and their household contacts (HHCs) took part in the study across 142 investigative sites in 15 countries from 10 October 2019 to 10 May 2024. A total of 4138 participants, 1457 IPs, and 2681 HHCs, were included in the study.

IPs received baloxavir marboxil or placebo in a 1:1 ratio, and their evaluable HHCs were assessed for influenza symptoms. No treatment was administered to the HHCs. Data was not collected at 'household' level in this study.

Participant milestones

Participant milestones
Measure
Placebo: IPs
IPs were randomized in this arm to receive a single dose of matching placebo orally as a tablet or oral suspension based on their weight and age.
Baloxavir Marboxil: IPs
IPs were randomized in this arm to receive a single dose of baloxavir marboxil orally based on their weight and age.
Placebo: HHCs
HHCs related to IPs randomized to the placebo arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Baloxavir Marboxil: HHCs
HHCs related to IPs randomized to the baloxavir marboxil arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Overall Study
STARTED
731
726
1336
1345
Overall Study
Treated
726
723
0
0
Overall Study
COMPLETED
699
688
1300
1305
Overall Study
NOT COMPLETED
32
38
36
40

Reasons for withdrawal

Reasons for withdrawal
Measure
Placebo: IPs
IPs were randomized in this arm to receive a single dose of matching placebo orally as a tablet or oral suspension based on their weight and age.
Baloxavir Marboxil: IPs
IPs were randomized in this arm to receive a single dose of baloxavir marboxil orally based on their weight and age.
Placebo: HHCs
HHCs related to IPs randomized to the placebo arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Baloxavir Marboxil: HHCs
HHCs related to IPs randomized to the baloxavir marboxil arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Overall Study
Adverse Event
1
0
0
0
Overall Study
Lost to Follow-up
2
2
2
2
Overall Study
Protocol Violation
0
0
0
1
Overall Study
Withdrawal by Subject
7
13
5
11
Overall Study
Physician Decision
0
0
1
0
Overall Study
Reason not Specified
22
23
28
26

Baseline Characteristics

Study to Assess the Efficacy of Baloxavir Marboxil Versus Placebo to Reduce Onward Transmission of Influenza A or B in Households

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure
Placebo: IPs
n=731 Participants
IPs were randomized in this arm to receive a single dose of matching placebo orally as a tablet or oral suspension based on their weight and age.
Baloxavir Marboxil: IPs
n=726 Participants
IPs were randomized in this arm to receive a single dose of baloxavir marboxil orally based on their weight and age.
Placebo: HHCs
n=1336 Participants
HHCs related to IPs randomized to the placebo arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Baloxavir Marboxil: HHCs
n=1341 Participants
HHCs related to IPs randomized to the baloxavir marboxil arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Total
n=4134 Participants
Total of all reporting groups
Age, Customized
2-11 years
65 Participants
n=5 Participants
65 Participants
n=7 Participants
152 Participants
n=5 Participants
151 Participants
n=4 Participants
433 Participants
n=21 Participants
Age, Customized
12-17 years
120 Participants
n=5 Participants
118 Participants
n=7 Participants
133 Participants
n=5 Participants
124 Participants
n=4 Participants
495 Participants
n=21 Participants
Age, Customized
18-64 years
546 Participants
n=5 Participants
543 Participants
n=7 Participants
985 Participants
n=5 Participants
989 Participants
n=4 Participants
3063 Participants
n=21 Participants
Age, Customized
65-84 years
0 Participants
n=5 Participants
0 Participants
n=7 Participants
61 Participants
n=5 Participants
71 Participants
n=4 Participants
132 Participants
n=21 Participants
Age, Customized
≥ 85 years
0 Participants
n=5 Participants
0 Participants
n=7 Participants
5 Participants
n=5 Participants
6 Participants
n=4 Participants
11 Participants
n=21 Participants
Sex: Female, Male
Female
377 Participants
n=5 Participants
389 Participants
n=7 Participants
740 Participants
n=5 Participants
709 Participants
n=4 Participants
2215 Participants
n=21 Participants
Sex: Female, Male
Male
354 Participants
n=5 Participants
337 Participants
n=7 Participants
596 Participants
n=5 Participants
632 Participants
n=4 Participants
1919 Participants
n=21 Participants
Ethnicity (NIH/OMB)
Hispanic or Latino
83 Participants
n=5 Participants
83 Participants
n=7 Participants
169 Participants
n=5 Participants
153 Participants
n=4 Participants
488 Participants
n=21 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
646 Participants
n=5 Participants
633 Participants
n=7 Participants
1133 Participants
n=5 Participants
1145 Participants
n=4 Participants
3557 Participants
n=21 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
2 Participants
n=5 Participants
10 Participants
n=7 Participants
34 Participants
n=5 Participants
43 Participants
n=4 Participants
89 Participants
n=21 Participants
Race (NIH/OMB)
American Indian or Alaska Native
7 Participants
n=5 Participants
7 Participants
n=7 Participants
9 Participants
n=5 Participants
8 Participants
n=4 Participants
31 Participants
n=21 Participants
Race (NIH/OMB)
Asian
196 Participants
n=5 Participants
190 Participants
n=7 Participants
370 Participants
n=5 Participants
364 Participants
n=4 Participants
1120 Participants
n=21 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants
n=5 Participants
0 Participants
n=7 Participants
10 Participants
n=5 Participants
0 Participants
n=4 Participants
10 Participants
n=21 Participants
Race (NIH/OMB)
Black or African American
28 Participants
n=5 Participants
19 Participants
n=7 Participants
47 Participants
n=5 Participants
46 Participants
n=4 Participants
140 Participants
n=21 Participants
Race (NIH/OMB)
White
483 Participants
n=5 Participants
495 Participants
n=7 Participants
817 Participants
n=5 Participants
871 Participants
n=4 Participants
2666 Participants
n=21 Participants
Race (NIH/OMB)
More than one race
3 Participants
n=5 Participants
0 Participants
n=7 Participants
9 Participants
n=5 Participants
5 Participants
n=4 Participants
17 Participants
n=21 Participants
Race (NIH/OMB)
Unknown or Not Reported
14 Participants
n=5 Participants
15 Participants
n=7 Participants
74 Participants
n=5 Participants
47 Participants
n=4 Participants
150 Participants
n=21 Participants

PRIMARY outcome

Timeframe: Baseline (Day 1) to Day 5

Population: The primary household contacts analysis set (PAS-HC) included unvaccinated HHCs who were linked to households where the IP was baseline PCR+ for influenza A or B, received the study drug, and where all contacts were PCR negative at baseline.

The virological transmission was determined based on Polymerase Chain Reaction Positive (PCR+) influenza test results. The adjusted incidence (cumulative proportion of events by Day 5) rate is reported here. This is defined as percentage of HHCs who tested PCR+ for influenza by Day 5 post IP randomization with virus subtype matching with that of the respective IP, irrespective of being symptomatic or asymptomatic. The adjusted incidence rates presented were estimated using a generalized estimating equations (GEE) approach.

Outcome measures

Outcome measures
Measure
Placebo: HHCs
n=1098 Participants
HHCs related to IPs randomized to the placebo arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Baloxavir Marboxil: HHCs
n=1118 Participants
HHCs related to IPs randomized to the baloxavir marboxil arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Percentage of HHCs With Virological Influenza Transmission by Day 5
13.42 percentage of HHCs
Interval 10.66 to 16.76
9.50 percentage of HHCs
Interval 7.4 to 12.13

SECONDARY outcome

Timeframe: Baseline (Day 1) to Day 5

Population: PAS-HC included unvaccinated HHCs who were linked to households where the IP was baseline PCR+ for influenza A or B, received the study drug, and where all contacts were PCR negative at baseline.

The adjusted incidence (cumulative proportion of events by Day 5) rate is reported here. This is defined as percentage of HHCs who tested PCR+ for influenza by Day 5 post IP randomization with virus subtype matching with that of respective IP, \& developed symptoms at any time during the study. The adjusted incidence rates presented were estimated using a GEE approach. HHCs ≥12 years old were symptomatic if 1. Presence of temperature ≥38.0 Celsius (C) and 1 respiratory symptom (cough, sore throat, nasal congestion) or 2. Presence of 1 respiratory symptom and 1 general systemic symptom (headache, feverishness or chills, muscle or joint pain, fatigue), with/without a fever. HHCs ≥2 and \<12 years old were symptomatic if the presence of temperature was ≥38.0°C and had upper respiratory tract infection signs or symptoms (cough, nasal congestion, or rhinorrhea). Symptoms must be either new or have worsened versus baseline in HHC with baseline symptoms due to a preexisting comorbidity.

Outcome measures

Outcome measures
Measure
Placebo: HHCs
n=1098 Participants
HHCs related to IPs randomized to the placebo arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Baloxavir Marboxil: HHCs
n=1118 Participants
HHCs related to IPs randomized to the baloxavir marboxil arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Percentage of HHCs With Symptomatic Influenza Transmission by Day 5
7.61 percentage of HHCs
95.38% Confidence Interval 5.66 • Interval 5.66 to 10.17
5.80 percentage of HHCs
95.38% Confidence Interval 4.10 • Interval 4.1 to 8.15

SECONDARY outcome

Timeframe: Baseline (Day 1) to Day 5

Population: Primary Households Analysis Set (PAS-HH) included all households of randomized IPs that were PCR+ at screening and with at least one HHC enrolled for the full study. IPs should be a part of the Primary Index Patients Analysis Set (PAS-IP) which includes all randomized IPs with at least 1 HHC in the PAS-HC. PAS-HC included unvaccinated HHCs who were linked to households where the IP was baseline PCR+ for influenza A/B, received study drug, and where all contacts were PCR negative at baseline.

Percentage of households with at least one HHC who met the primary endpoint of virological transmission by Day 5 are reported here. 'Number of participants analyzed' is the number of IPs in the PAS-IP set.

Outcome measures

Outcome measures
Measure
Placebo: HHCs
n=544 Households
HHCs related to IPs randomized to the placebo arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Baloxavir Marboxil: HHCs
n=548 Households
HHCs related to IPs randomized to the baloxavir marboxil arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Percentage of Households (HHs) With Virological Influenza Transmission at Household Level by Day 5
19.5 percentage of HHs
15.5 percentage of HHs

SECONDARY outcome

Timeframe: Baseline (Day 1) to Day 5

Population: PAS-HH included all households of randomized IPs that were PCR+ at screening and with at least one HHC enrolled for the full study. The IPs should be a part of the PAS-IP which includes all randomized IPs with at least one HHC in the PAS-HC. PAS-HC included unvaccinated HHCs who were linked to households where the IP was baseline PCR+ for influenza A or B, received the study drug, and where all contacts were PCR negative at baseline.

Percentage of HHs with at least one HHC who meets the symptomatic transmission by Day 5 endpoint are reported here. 'Number of participants analyzed' is the number of IPs in the PAS-IP set.

Outcome measures

Outcome measures
Measure
Placebo: HHCs
n=544 Participants
HHCs related to IPs randomized to the placebo arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Baloxavir Marboxil: HHCs
n=548 Participants
HHCs related to IPs randomized to the baloxavir marboxil arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Percentage of HHs With Symptomatic Influenza Transmission at Household Level by Day 5
11.9 percentage of HHs
8.6 percentage of HHs

SECONDARY outcome

Timeframe: Baseline (Day 1) to Day 9

Population: PAS-HC analysis set included unvaccinated HHCs who were linked to households where the IP was baseline PCR+ for influenza A or B, received the study drug, and where all contacts were PCR negative at baseline. Overall number analyzed included number of HHCs with data available for analysis.

The adjusted incidence (cumulative proportion of events by Day 9) rate is reported here. This is defined as percentage of HHCs who tested PCR+ for influenza by Day 9 post IP randomization with virus subtype matching with the respective IP, irrespective of being symptomatic or asymptomatic including: 1. all HHC meeting primary endpoint, AND 2. all HHC cases detected after Day 5 meeting the following criteria: 2a. included HHC case was in an HH where another HHC had already met the primary endpoint OR 2b. included HHC case was PCR+ bearing an amino acid substitution of isoleucine for another amino acid at position 38 (I38X) in the polymerase acidic (PA) protein (PA/I38X substitution) or amino acid substitution of threonine to lysine at position 20 in the PA protein for influenza B only (PA/T20K). The adjusted incidence rates presented were estimated using a GEE approach.

Outcome measures

Outcome measures
Measure
Placebo: HHCs
n=1038 Participants
HHCs related to IPs randomized to the placebo arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Baloxavir Marboxil: HHCs
n=1081 Participants
HHCs related to IPs randomized to the baloxavir marboxil arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Percentage of HHCs With Virological Influenza Transmission by Day 9
15.40 percentage of HHCs
95.38% Confidence Interval 12.20 • Interval 12.2 to 19.27
10.77 percentage of HHCs
95.38% Confidence Interval 8.41 • Interval 8.41 to 13.71

SECONDARY outcome

Timeframe: Baseline (Day 1) to Day 9

Population: PAS-HC included unvaccinated HHCs who were linked to households where IP was baseline PCR+ for influenza A or B, received study drug, and where all contacts were PCR negative at baseline. Overall number analyzed is the number of participants with data available for analysis.

The adjusted incidence (cumulative proportion of events by Day 9) rate is reported here. This is defined as percentage of HHCs who met the virological transmission by Day 9 endpoint and developed symptoms at any time during the study. The adjusted incidence rates presented were estimated using a GEE approach. HHCs ≥12 years were symptomatic if they had 1. temperature ≥38.0°C and one respiratory symptom (cough, sore throat, nasal congestion) or 2. one respiratory and one general systemic symptom (headache, feverishness or chills, muscle or joint pain, fatigue), with or without fever. HHCs ≥2 and \<12 years were symptomatic if the presence of temperature was ≥38.0°C and had upper respiratory symptoms (headache, feverishness or chills, muscle or joint pain, fatigue). Symptoms must be either new or have worsened versus baseline in HHC with baseline symptoms due to a preexisting comorbidity.

Outcome measures

Outcome measures
Measure
Placebo: HHCs
n=1037 Participants
HHCs related to IPs randomized to the placebo arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Baloxavir Marboxil: HHCs
n=1079 Participants
HHCs related to IPs randomized to the baloxavir marboxil arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Percentage of HHCs With Symptomatic Influenza Transmission by Day 9
8.26 percentage of HHCs
Interval 6.1 to 11.09
6.15 percentage of HHCs
Interval 4.37 to 8.58

SECONDARY outcome

Timeframe: Baseline (Day 1) to Day 9

Population: PAS-HC included unvaccinated HHCs who were linked to households where the IP was baseline PCR+ for influenza A or B and received study drug and where all contacts were PCR negative at baseline. Overall number analyzed is the number of participants with data available for analysis.

Virological infection was defined as HHCs who tested PCR+ for influenza by Day 9 post IP randomization based on PCR influenza test results. The adjusted incidence (cumulative proportion of events by Day 9) rate is reported here. This is defined as percentage of HHCs who met the virological infection by Day 9 endpoint. The adjusted incidence rates presented were estimated using a GEE approach.

Outcome measures

Outcome measures
Measure
Placebo: HHCs
n=1040 Participants
HHCs related to IPs randomized to the placebo arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Baloxavir Marboxil: HHCs
n=1071 Participants
HHCs related to IPs randomized to the baloxavir marboxil arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Percentage of HHCs With Any Virological Infection by Day 9
18.68 percentage of HHCs
95.38% Confidence Interval 15.36 • Interval 15.36 to 22.53
13.98 percentage of HHCs
95.38% Confidence Interval 11.31 • Interval 11.31 to 17.16

SECONDARY outcome

Timeframe: Baseline (Day 1) to Day 9

Population: PAS-HH included all households of randomized IPs that were PCR+ at screening and with at least one HHC enrolled for the full study. The IPs should be a part of the PAS-IP which includes all randomized IPs with at least one HHC in the PAS-HC. PAS-HC included unvaccinated HHCs who were linked to households where the IP was baseline PCR+ for influenza A or B, received the study drug, and where all contacts were PCR negative at baseline.

Virological infection at the HH level was defined as the HHs with at least one HHC who met the endpoint of any virological infection by Day 9. 'Number of participants analyzed' is the number of IPs in the PAS-IP set.

Outcome measures

Outcome measures
Measure
Placebo: HHCs
n=544 Households
HHCs related to IPs randomized to the placebo arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Baloxavir Marboxil: HHCs
n=548 Households
HHCs related to IPs randomized to the baloxavir marboxil arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Percentage of HHs With Any Virological Infection at HH Level by Day 9
24.3 percentage of HHs
20.1 percentage of HHs

SECONDARY outcome

Timeframe: Baseline (Day 1) to Day 9

Population: PAS-HC included unvaccinated HHCs who were linked to households where the IP was baseline PCR+ for influenza A or B and received study drug and where all contacts were PCR negative at baseline. Overall number analyzed is the number of participants with data available for analysis.

The adjusted incidence (cumulative proportion of events by Day 9) rate is reported here. This is defined as percentage of HHCs who tested PCR+ for influenza by Day 9 post IP randomization and developed symptoms at any time during the study. The adjusted incidence rates presented were estimated using a GEE approach. HHCs ≥12 years were symptomatic if they had (1) a temperature ≥38.0°C and one respiratory symptom (cough, sore throat, nasal congestion) or (2) one respiratory and one systemic symptom (headache, chills, muscle/joint pain, fatigue), with or without fever. HHCs ≥2 and \<12 years were symptomatic if the presence of temperature was ≥38.0°C and had upper respiratory symptoms (cough, nasal congestion, rhinorrhea). Symptoms must be either new or have worsened versus baseline in HHC with baseline symptoms due to a preexisting comorbidity.

Outcome measures

Outcome measures
Measure
Placebo: HHCs
n=1039 Participants
HHCs related to IPs randomized to the placebo arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Baloxavir Marboxil: HHCs
n=1069 Participants
HHCs related to IPs randomized to the baloxavir marboxil arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Percentage of HHCs With Any Symptomatic Infection by Day 9
8.71 percentage of HHCs
95.38% Confidence Interval 6.49 • Interval 6.49 to 11.6
6.43 percentage of HHCs
95.38% Confidence Interval 4.61 • Interval 4.61 to 8.91

SECONDARY outcome

Timeframe: Baseline (Day 1) to Day 9

Population: PAS-HH included all households of randomized IPs that were PCR+ at screening and with at least one HHC enrolled for the full study. The IPs should be a part of the PAS-IP which includes all randomized IPs with at least one HHC in the PAS-HC. PAS-HC included unvaccinated HHCs who were linked to households where the IP was baseline PCR+ for influenza A or B, received the study drug, and where all contacts were PCR negative at baseline.

Percentage of HHs with at least one HHC who meets the endpoint of any symptomatic infection by Day 9 are reported here. HHCs ≥12 years were symptomatic if they had 1. a temperature ≥38.0°C \&1 respiratory symptom (cough, sore throat, nasal congestion) or 2. 1 respiratory \& 1 systemic symptom (headache, chills, muscle/joint pain, fatigue), with/without fever. HHCs ≥2 \& \<12 years were symptomatic if the temperature was ≥38.0°C \& had upper respiratory symptoms (cough, nasal congestion, rhinorrhea). Symptoms must be new or have worsened versus baseline in HHC with baseline symptoms due to preexisting comorbidity. 'Number of participants analyzed' is the number of IPs in the PAS-IP set.

Outcome measures

Outcome measures
Measure
Placebo: HHCs
n=544 Households
HHCs related to IPs randomized to the placebo arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Baloxavir Marboxil: HHCs
n=548 Households
HHCs related to IPs randomized to the baloxavir marboxil arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Percentage of HHs With Any Symptomatic Infection at HH Level by Day 9
12.9 percentage of HHs
9.5 percentage of HHs

SECONDARY outcome

Timeframe: Baseline up to Day 9 (for IPs ≥12 years old) and Day 21 (for IPs <12 years old)

Population: Safety IP Set included all randomized participants who received at least one dose of study treatment. One participant was randomized to placebo but received baloxavir and is counted in the Baloxavir arm.

An AE is any untoward medical occurrence in a participant administered a pharmaceutical product and regardless of causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal (investigational) product, whether or not considered related to the medicinal (investigational) product.

Outcome measures

Outcome measures
Measure
Placebo: HHCs
n=726 Participants
HHCs related to IPs randomized to the placebo arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Baloxavir Marboxil: HHCs
n=723 Participants
HHCs related to IPs randomized to the baloxavir marboxil arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Number of IPs With Adverse Events (AEs)
51 Participants
33 Participants

SECONDARY outcome

Timeframe: Baseline up to Day 9 (for IPs ≥12 years old) and Day 21 (for IPs <12 years old)

Population: Safety IP Set included all randomized participants who received at least one dose of study treatment. One participant was randomized to placebo but received baloxavir and is counted in the Baloxavir arm.

A SAE is any significant hazard, contraindication, side effect that is fatal or life-threatening, requires hospitalization or prolongation of an existing hospitalization, results in persistent or significant disability or incapacity, is a congenital anomaly or birth defect, is medically significant or requires intervention to prevent one or other of the outcomes listed above.

Outcome measures

Outcome measures
Measure
Placebo: HHCs
n=726 Participants
HHCs related to IPs randomized to the placebo arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Baloxavir Marboxil: HHCs
n=723 Participants
HHCs related to IPs randomized to the baloxavir marboxil arm were evaluated for influenza transmission (either virological or symptomatic) up to Day 9 of the observation period without any treatment being administered.
Number of IPs With Serious Adverse Events (SAEs)
2 Participants
1 Participants

Adverse Events

Placebo: IPs

Serious events: 2 serious events
Other events: 0 other events
Deaths: 0 deaths

Baloxavir Marboxil: IPs

Serious events: 1 serious events
Other events: 0 other events
Deaths: 0 deaths

Serious adverse events

Serious adverse events
Measure
Placebo: IPs
n=726 participants at risk
IPs were randomized in this arm to receive a single dose of matching placebo orally as a tablet or oral suspension based on their weight and age.
Baloxavir Marboxil: IPs
n=723 participants at risk
IPs received a single dose of baloxavir marboxil orally based on their weight and age.
Infections and infestations
Bronchitis
0.14%
1/726 • Number of events 1 • Baseline up to Day 9 (IPs ≥12 years old) Baseline up to Day 21 (IPs <12 years old)
Safety IP Set included all randomized participants who received at least one dose of study treatment. One participant was randomized to placebo but received baloxavir and is counted in the Baloxavir arm. Safety data was collected only for IPs as no treatment was administered to the HHCs in this study.
0.00%
0/723 • Baseline up to Day 9 (IPs ≥12 years old) Baseline up to Day 21 (IPs <12 years old)
Safety IP Set included all randomized participants who received at least one dose of study treatment. One participant was randomized to placebo but received baloxavir and is counted in the Baloxavir arm. Safety data was collected only for IPs as no treatment was administered to the HHCs in this study.
Infections and infestations
Pneumonia
0.14%
1/726 • Number of events 1 • Baseline up to Day 9 (IPs ≥12 years old) Baseline up to Day 21 (IPs <12 years old)
Safety IP Set included all randomized participants who received at least one dose of study treatment. One participant was randomized to placebo but received baloxavir and is counted in the Baloxavir arm. Safety data was collected only for IPs as no treatment was administered to the HHCs in this study.
0.00%
0/723 • Baseline up to Day 9 (IPs ≥12 years old) Baseline up to Day 21 (IPs <12 years old)
Safety IP Set included all randomized participants who received at least one dose of study treatment. One participant was randomized to placebo but received baloxavir and is counted in the Baloxavir arm. Safety data was collected only for IPs as no treatment was administered to the HHCs in this study.
Metabolism and nutrition disorders
Hyponatraemia
0.14%
1/726 • Number of events 1 • Baseline up to Day 9 (IPs ≥12 years old) Baseline up to Day 21 (IPs <12 years old)
Safety IP Set included all randomized participants who received at least one dose of study treatment. One participant was randomized to placebo but received baloxavir and is counted in the Baloxavir arm. Safety data was collected only for IPs as no treatment was administered to the HHCs in this study.
0.00%
0/723 • Baseline up to Day 9 (IPs ≥12 years old) Baseline up to Day 21 (IPs <12 years old)
Safety IP Set included all randomized participants who received at least one dose of study treatment. One participant was randomized to placebo but received baloxavir and is counted in the Baloxavir arm. Safety data was collected only for IPs as no treatment was administered to the HHCs in this study.
Pregnancy, puerperium and perinatal conditions
Abortion spontaneous
0.00%
0/726 • Baseline up to Day 9 (IPs ≥12 years old) Baseline up to Day 21 (IPs <12 years old)
Safety IP Set included all randomized participants who received at least one dose of study treatment. One participant was randomized to placebo but received baloxavir and is counted in the Baloxavir arm. Safety data was collected only for IPs as no treatment was administered to the HHCs in this study.
0.14%
1/723 • Number of events 1 • Baseline up to Day 9 (IPs ≥12 years old) Baseline up to Day 21 (IPs <12 years old)
Safety IP Set included all randomized participants who received at least one dose of study treatment. One participant was randomized to placebo but received baloxavir and is counted in the Baloxavir arm. Safety data was collected only for IPs as no treatment was administered to the HHCs in this study.

Other adverse events

Adverse event data not reported

Additional Information

Medical Communications

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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