Trial Outcomes & Findings for A Two-Arm Study to Evaluate the Pharmacokinetics, Efficacy, and Safety of Subcutaneous Administration of the Fixed-Dose Combination of Pertuzumab and Trastuzumab in Combination With Chemotherapy in Chinese Participants With HER2-Positive Early Breast Cancer (NCT NCT04024462)

NCT ID: NCT04024462

Last Updated: 2025-12-03

Results Overview

The observed pertuzumab trough serum concentration (Ctrough) at Cycle 7 was assessed following 3 cycles of pertuzumab IV and trastuzumab IV or the fixed-dose combination (FDC) of pertuzumab and trastuzumab SC. The Per Protocol Pharmacokinetics (PK) analysis population includes all enrolled participants who adhered to the protocol. Exclusions from the Per Protocol PK analysis population were made for the following reasons: participants were missing the Ctrough pre-dose Cycle 8 PK sample, participants with a Ctrough sample collected with at least 2 days deviation from the planned date on Day 21 (i.e., before Day 19 or after Day 23), participants given a dose amount that deviated from the planned dose by \>20% within 3 cycles (from Cycle 5), participants with a dose delay of more than 7 days, a Cycle 7 subcutaneous injection site other than thigh was used, if the Cycle 8 IV pre-dose and post-dose PK samples were switched, and an assay error impacting Ctrough measurement.

• Recruitment status: ACTIVE_NOT_RECRUITING
• Study phase: PHASE3
• Target enrollment: 200 participants
• Primary outcome timeframe: Pre-dose at Cycle 8 (one cycle is 21 days)
• Results posted on: 2025-12-03

Participant Flow

Participants were enrolled at 18 investigational sites in China.

Participants with human epidermal growth factor receptor 2 (HER2)-positive early breast cancer, who were candidates for preoperative neoadjuvant treatment in the clinical practice, were enrolled in the study.

Participant milestones

Measure	Arm A: Pertuzumab IV + Trastuzumab IV + Chemotherapy Participants received 8 cycles of neoadjuvant chemotherapy: 4 cycles of doxorubicin plus cyclophosphamide (AC) once every 3 weeks (Q3W) followed by docetaxel Q3W for 4 cycles. Pertuzumab and trastuzumab were given intravenously (IV) for 4 cycles Q3W concurrently with the taxane component of chemotherapy. After completing their neoadjuvant therapy, participants underwent surgery. Thereafter, participants received an additional 14 cycles of pertuzumab IV and trastuzumab IV for a total of 18 cycles.	Arm B: Pertuzumab and Trastuzumab FDC SC + Chemotherapy Participants received 8 cycles of neoadjuvant chemotherapy: 4 cycles of AC Q3W followed by docetaxel Q3W for 4 cycles. The pertuzumab and trastuzumab fixed-dose combination for subcutaneous administration (PH FDC SC) were given subcutaneously (SC) for 4 cycles (Q3W) concurrently with the taxane component of chemotherapy. After completing their neoadjuvant therapy, participants underwent surgery. Thereafter, participants received an additional 14 cycles of the PH FDC SC for a total of 18 cycles.
Overall Study STARTED	101	99
Overall Study Completed Neoadjuvant Treatment (24 Weeks)	96	95
Overall Study Completed Surgery (<9 Weeks)	94	93
Overall Study Started Adjuvant Treatment	89	89
Overall Study Completed Adjuvant Treatment (42 Weeks)	12	14
Overall Study Started Follow-Up (≥3 Years)	23	20
Overall Study COMPLETED	0	0
Overall Study NOT COMPLETED	101	99

Reasons for withdrawal

Measure	Arm A: Pertuzumab IV + Trastuzumab IV + Chemotherapy Participants received 8 cycles of neoadjuvant chemotherapy: 4 cycles of doxorubicin plus cyclophosphamide (AC) once every 3 weeks (Q3W) followed by docetaxel Q3W for 4 cycles. Pertuzumab and trastuzumab were given intravenously (IV) for 4 cycles Q3W concurrently with the taxane component of chemotherapy. After completing their neoadjuvant therapy, participants underwent surgery. Thereafter, participants received an additional 14 cycles of pertuzumab IV and trastuzumab IV for a total of 18 cycles.	Arm B: Pertuzumab and Trastuzumab FDC SC + Chemotherapy Participants received 8 cycles of neoadjuvant chemotherapy: 4 cycles of AC Q3W followed by docetaxel Q3W for 4 cycles. The pertuzumab and trastuzumab fixed-dose combination for subcutaneous administration (PH FDC SC) were given subcutaneously (SC) for 4 cycles (Q3W) concurrently with the taxane component of chemotherapy. After completing their neoadjuvant therapy, participants underwent surgery. Thereafter, participants received an additional 14 cycles of the PH FDC SC for a total of 18 cycles.
Overall Study Withdrawal by Subject	6	7
Overall Study Progressive Disease	0	1
Overall Study Adverse Event	0	1
Overall Study Death	0	1
Overall Study Lost to Follow-up	1	0
Overall Study Ongoing in the Study	94	89

Baseline Characteristics

A Two-Arm Study to Evaluate the Pharmacokinetics, Efficacy, and Safety of Subcutaneous Administration of the Fixed-Dose Combination of Pertuzumab and Trastuzumab in Combination With Chemotherapy in Chinese Participants With HER2-Positive Early Breast Cancer

Baseline characteristics by cohort

Measure	Arm A: Pertuzumab IV + Trastuzumab IV + Chemotherapy n=101 Participants Participants received 8 cycles of neoadjuvant chemotherapy: 4 cycles of doxorubicin plus cyclophosphamide (AC) once every 3 weeks (Q3W) followed by docetaxel Q3W for 4 cycles. Pertuzumab and trastuzumab were given intravenously (IV) for 4 cycles Q3W concurrently with the taxane component of chemotherapy. After completing their neoadjuvant therapy, participants underwent surgery. Thereafter, participants received an additional 14 cycles of pertuzumab IV and trastuzumab IV for a total of 18 cycles.	Arm B: Pertuzumab and Trastuzumab FDC SC + Chemotherapy n=99 Participants Participants received 8 cycles of neoadjuvant chemotherapy: 4 cycles of AC Q3W followed by docetaxel Q3W for 4 cycles. The pertuzumab and trastuzumab fixed-dose combination for subcutaneous administration (PH FDC SC) were given subcutaneously (SC) for 4 cycles (Q3W) concurrently with the taxane component of chemotherapy. After completing their neoadjuvant therapy, participants underwent surgery. Thereafter, participants received an additional 14 cycles of the PH FDC SC for a total of 18 cycles.	Total n=200 Participants Total of all reporting groups
Age, Continuous	51.17 Years STANDARD_DEVIATION 10.55 • n=3 Participants	50.42 Years STANDARD_DEVIATION 10.01 • n=3 Participants	50.80 Years STANDARD_DEVIATION 10.27 • n=6 Participants
Sex: Female, Male Female	101 Participants n=3 Participants	99 Participants n=3 Participants	200 Participants n=6 Participants
Sex: Female, Male Male	0 Participants n=3 Participants	0 Participants n=3 Participants	0 Participants n=6 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	0 Participants n=3 Participants	0 Participants n=3 Participants	0 Participants n=6 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	101 Participants n=3 Participants	99 Participants n=3 Participants	200 Participants n=6 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=3 Participants	0 Participants n=3 Participants	0 Participants n=6 Participants
Race/Ethnicity, Customized Asian	101 Participants n=3 Participants	99 Participants n=3 Participants	200 Participants n=6 Participants
Randomization Stratification Factors: Hormone Receptor Status ER Negative and PgR Negative	51 Participants n=3 Participants	51 Participants n=3 Participants	102 Participants n=6 Participants
Randomization Stratification Factors: Hormone Receptor Status ER Positive and PgR Positive	50 Participants n=3 Participants	48 Participants n=3 Participants	98 Participants n=6 Participants
Randomization Stratification Factors: Clinical Stage at Presentation Stage II-IIIA	70 Participants n=3 Participants	70 Participants n=3 Participants	140 Participants n=6 Participants
Randomization Stratification Factors: Clinical Stage at Presentation Stage IIIB-IIIC	31 Participants n=3 Participants	29 Participants n=3 Participants	60 Participants n=6 Participants

PRIMARY outcome

Timeframe: Pre-dose at Cycle 8 (one cycle is 21 days)

Population: Pertuzumab Per Protocol PK Population: includes only participants who adhered to the pre-specified criteria for the schedule of pharmacokinetic assessments.

The observed pertuzumab trough serum concentration (Ctrough) at Cycle 7 was assessed following 3 cycles of pertuzumab IV and trastuzumab IV or the fixed-dose combination (FDC) of pertuzumab and trastuzumab SC. The Per Protocol Pharmacokinetics (PK) analysis population includes all enrolled participants who adhered to the protocol. Exclusions from the Per Protocol PK analysis population were made for the following reasons: participants were missing the Ctrough pre-dose Cycle 8 PK sample, participants with a Ctrough sample collected with at least 2 days deviation from the planned date on Day 21 (i.e., before Day 19 or after Day 23), participants given a dose amount that deviated from the planned dose by >20% within 3 cycles (from Cycle 5), participants with a dose delay of more than 7 days, a Cycle 7 subcutaneous injection site other than thigh was used, if the Cycle 8 IV pre-dose and post-dose PK samples were switched, and an assay error impacting Ctrough measurement.

Outcome measures

Measure	Arm A: Pertuzumab IV + Trastuzumab IV + Chemotherapy n=89 Participants Participants received 8 cycles of neoadjuvant chemotherapy: 4 cycles of doxorubicin plus cyclophosphamide (AC) once every 3 weeks (Q3W) followed by docetaxel Q3W for 4 cycles. Pertuzumab and trastuzumab were given intravenously (IV) for 4 cycles Q3W concurrently with the taxane component of chemotherapy. After completing their neoadjuvant therapy, participants underwent surgery. Thereafter, participants received an additional 14 cycles of pertuzumab IV and trastuzumab IV for a total of 18 cycles.	Arm B: Pertuzumab and Trastuzumab FDC SC + Chemotherapy n=89 Participants Participants received 8 cycles of neoadjuvant chemotherapy: 4 cycles of AC Q3W followed by docetaxel Q3W for 4 cycles. The pertuzumab and trastuzumab fixed-dose combination for subcutaneous administration (PH FDC SC) were given subcutaneously (SC) for 4 cycles (Q3W) concurrently with the taxane component of chemotherapy. After completing their neoadjuvant therapy, participants underwent surgery. Thereafter, participants received an additional 14 cycles of the PH FDC SC for a total of 18 cycles.
Serum Trough Concentration (Ctrough) of Pertuzumab During Cycle 7 (Pre-Dose Cycle 8)	69.9 micrograms per millilitre (μg/mL) Geometric Coefficient of Variation 30.8	74.6 micrograms per millilitre (μg/mL) Geometric Coefficient of Variation 30.5

PRIMARY outcome

Timeframe: Pre-dose at Cycle 8 (one cycle is 21 days)

Population: Trastuzumab Per Protocol PK Population: includes only participants who adhered to the pre-specified criteria for the schedule of pharmacokinetic assessments.

The observed trastuzumab trough serum concentration (Ctrough) at Cycle 7 was assessed following 3 cycles of pertuzumab IV and trastuzumab IV or the fixed-dose combination (FDC) of pertuzumab and trastuzumab SC. The Per Protocol Pharmacokinetics (PK) analysis population includes all enrolled participants who adhered to the protocol. Exclusions from the Per Protocol PK analysis population were made for the following reasons: participants were missing the Ctrough pre-dose Cycle 8 PK sample, participants with a Ctrough sample collected with at least 2 days deviation from the planned date on Day 21 (i.e., before Day 19 or after Day 23), participants given a dose amount that deviated from the planned dose by >20% within 3 cycles (from Cycle 5), participants with a dose delay of more than 7 days, a Cycle 7 subcutaneous injection site other than thigh was used, if the Cycle 8 IV pre-dose and post-dose PK samples were switched, and an assay error impacting Ctrough measurement.

Outcome measures

Measure	Arm A: Pertuzumab IV + Trastuzumab IV + Chemotherapy n=89 Participants Participants received 8 cycles of neoadjuvant chemotherapy: 4 cycles of doxorubicin plus cyclophosphamide (AC) once every 3 weeks (Q3W) followed by docetaxel Q3W for 4 cycles. Pertuzumab and trastuzumab were given intravenously (IV) for 4 cycles Q3W concurrently with the taxane component of chemotherapy. After completing their neoadjuvant therapy, participants underwent surgery. Thereafter, participants received an additional 14 cycles of pertuzumab IV and trastuzumab IV for a total of 18 cycles.	Arm B: Pertuzumab and Trastuzumab FDC SC + Chemotherapy n=89 Participants Participants received 8 cycles of neoadjuvant chemotherapy: 4 cycles of AC Q3W followed by docetaxel Q3W for 4 cycles. The pertuzumab and trastuzumab fixed-dose combination for subcutaneous administration (PH FDC SC) were given subcutaneously (SC) for 4 cycles (Q3W) concurrently with the taxane component of chemotherapy. After completing their neoadjuvant therapy, participants underwent surgery. Thereafter, participants received an additional 14 cycles of the PH FDC SC for a total of 18 cycles.
Serum Ctrough of Trastuzumab During Cycle 7 (Pre-Dose Cycle 8)	33.6 micrograms per milllilitre (μg/mL) Geometric Coefficient of Variation 28.8	52.1 micrograms per milllilitre (μg/mL) Geometric Coefficient of Variation 32.5

SECONDARY outcome

Timeframe: Following completion of surgery (up to 33 weeks)

Population: ITT Population: includes all enrolled participants.

Total pathological complete response (tpCR) was defined as eradication of invasive disease in the breast and axilla; that is, ypT0/is ypN0, according to the local pathologists' assessment. Pathologic response to therapy was determined at the time of surgery. The tpCR rate is the percentage of participants in the ITT population who achieved a tpCR. Participants with missing data for tpCR (i.e., do not undergo surgery or have an invalid pCR assessment) were included in the analysis and classified as non-responders. Rates of tpCR were calculated in each treatment arm and were assessed using the difference between the Arm B: Pertuzumab and Trastuzumab FDC SC and the Arm A: Pertuzumab IV and Trastuzumab IV tpCR rates and corresponding 95% Clopper-Pearson confidence intervals (CIs). The difference between the tpCR rates along with corresponding 95% Hauck-Anderson CIs were calculated.

Outcome measures

Measure	Arm A: Pertuzumab IV + Trastuzumab IV + Chemotherapy n=101 Participants Participants received 8 cycles of neoadjuvant chemotherapy: 4 cycles of doxorubicin plus cyclophosphamide (AC) once every 3 weeks (Q3W) followed by docetaxel Q3W for 4 cycles. Pertuzumab and trastuzumab were given intravenously (IV) for 4 cycles Q3W concurrently with the taxane component of chemotherapy. After completing their neoadjuvant therapy, participants underwent surgery. Thereafter, participants received an additional 14 cycles of pertuzumab IV and trastuzumab IV for a total of 18 cycles.	Arm B: Pertuzumab and Trastuzumab FDC SC + Chemotherapy n=99 Participants Participants received 8 cycles of neoadjuvant chemotherapy: 4 cycles of AC Q3W followed by docetaxel Q3W for 4 cycles. The pertuzumab and trastuzumab fixed-dose combination for subcutaneous administration (PH FDC SC) were given subcutaneously (SC) for 4 cycles (Q3W) concurrently with the taxane component of chemotherapy. After completing their neoadjuvant therapy, participants underwent surgery. Thereafter, participants received an additional 14 cycles of the PH FDC SC for a total of 18 cycles.
Percentage of Participants With Total Pathological Complete Response (tpCR), According to Local Pathologist Assessment	56.4 percentage of participants Interval 46.2 to 66.28	55.6 percentage of participants Interval 45.22 to 65.55

SECONDARY outcome

Timeframe: From date of surgery to iDFS (excluding SPNBC) event (up to 5 years)

iDFS (excluding SPNBC) is defined as the time from the first date of no disease (i.e., the date of primary surgery) to the first occurrence of one of the following events: ipsilateral invasive breast tumor recurrence; ipsilateral local-regional invasive breast cancer reccurrence; distant recurrence; contralateral invasive breast cancer; or death attributable to any cause. Ipsilateral or contralateral in situ disease and SPNBC (including in situ carcinomas and non-melanoma skin cancers) will not be counted as progressive disease or relapse.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From date of surgery to iDFS (including SPNBC) event (up to 5 years)

iDFS including SPNBC is defined in the same way as iDFS but including SPNBC as an event (with the exception of non-melanoma skin cancers and in situ carcinoma of any site).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From baseline to EFS (excluding SPNBC) event (up to 5.5 years)

EFS (excluding SPNBC) is defined as the time from enrollment to the first occurrence of one of the following events: breast cancer progression; breast cancer recurrence; or death from any cause. Ipsilateral or contralateral in situ disease and SPNBC (including in situ carcinomas and non-melanoma skin cancers) will not be counted as progressive disease or relapse.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From baseline to EFS (including SPNBC) event (up to 5.5 years)

EFS including SPNBC is defined in the same way as EFS, but including SPNBC as an event (with the exception of non-melanoma skin cancers and in situ carcinoma of any site).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From baseline to DFRI event (up to 5.5 years)

DRFI is defined as the time between randomization and the date of distant breast cancer recurrence.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From baseline to death from any cause (up to 5.5 years)

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From baseline until study completion (up to 5.5 years)

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From baseline until study completion (up to 5.5 years)

A primary cardiac event is defined as either a symptomatic ejection fraction decrease (heart failure) of New York Heart Association (NYHA) Class III/IV and a drop in left ventricular ejection fraction (LVEF) of at least 10-percentage points from baseline and to below 50%, or a definite or probable cardiac death. NYHA Class III is defined as: marked limitation of physical activity; comfortable at rest, but less than ordinary activity causes fatigue, palpitation, or dyspnea. NYHA Class IV is defined as: Inability to carry on any physical activity without discomfort; symptoms of cardiac insufficiency at rest; if any physical activity is undertaken, discomfort is increased. Definite cardiac death is defined as death due to heart failure, myocardial infarction, or documented primary arrhythmia. Probable cardiac death is defined as sudden unexpected death within 24 hours of a definite or probable cardiac event (e.g., syncope, cardiac arrest, chest pain, etc.) without documented etiology.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From baseline until study completion (up to 5.5 years)

An LVSD ("Ejection fraction decreased") of NYHA Class II is defined as a left ventricular ejection fraction (LVEF) decrease of ≥10-percentage points below the baseline measurement to an absolute LVEF value of <50%, confirmed by a second LVEF assessment within approximately 3 weeks also showing a documented drop.

Outcome measures

Outcome data not reported

Adverse Events

Arm A: Pertuzumab IV + Trastuzumab IV + Chemotherapy

Serious events: 19 serious events

Other events: 96 other events

Deaths: 0 deaths

Arm B: Pertuzumab and Trastuzumab FDC SC + Chemotherapy

Serious events: 18 serious events

Other events: 98 other events

Deaths: 1 deaths

Serious adverse events

Measure	Arm A: Pertuzumab IV + Trastuzumab IV + Chemotherapy n=100 participants at risk Participants received 8 cycles of neoadjuvant chemotherapy: 4 cycles of doxorubicin plus cyclophosphamide (AC) once every 3 weeks (Q3W) followed by docetaxel Q3W for 4 cycles. Pertuzumab and trastuzumab were given intravenously (IV) for 4 cycles Q3W concurrently with the taxane component of chemotherapy. After completing their neoadjuvant therapy, participants underwent surgery. Thereafter, participants received an additional 14 cycles of pertuzumab IV and trastuzumab IV for a total of 18 cycles.	Arm B: Pertuzumab and Trastuzumab FDC SC + Chemotherapy n=100 participants at risk Participants received 8 cycles of neoadjuvant chemotherapy: 4 cycles of AC Q3W followed by docetaxel Q3W for 4 cycles. The pertuzumab and trastuzumab fixed-dose combination for subcutaneous administration (PH FDC SC) were given subcutaneously (SC) for 4 cycles (Q3W) concurrently with the taxane component of chemotherapy. After completing their neoadjuvant therapy, participants underwent surgery. Thereafter, participants received an additional 14 cycles of the PH FDC SC for a total of 18 cycles.
Blood and lymphatic system disorders ANAEMIA	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Blood and lymphatic system disorders FEBRILE NEUTROPENIA	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	3.0% 3/100 • Number of events 3 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Blood and lymphatic system disorders MYELOSUPPRESSION	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Cardiac disorders CARDIAC FAILURE	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Cardiac disorders MYOCARDIAL INFARCTION	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Gastrointestinal disorders ILEUS	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
General disorders SUDDEN CARDIAC DEATH	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Hepatobiliary disorders DRUG-INDUCED LIVER INJURY	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Hepatobiliary disorders HEPATIC FUNCTION ABNORMAL	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Hepatobiliary disorders LIVER INJURY	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Infections and infestations GASTROENTERITIS	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Infections and infestations PNEUMONIA	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Infections and infestations POSTOPERATIVE WOUND INFECTION	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	2.0% 2/100 • Number of events 2 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Infections and infestations UPPER RESPIRATORY TRACT INFECTION	2.0% 2/100 • Number of events 2 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Injury, poisoning and procedural complications RADIATION SKIN INJURY	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Injury, poisoning and procedural complications SKIN FLAP NECROSIS	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations ALANINE AMINOTRANSFERASE INCREASED	4.0% 4/100 • Number of events 4 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations ASPARTATE AMINOTRANSFERASE INCREASED	3.0% 3/100 • Number of events 3 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations EJECTION FRACTION DECREASED	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations GAMMA-GLUTAMYLTRANSFERASE INCREASED	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations NEUTROPHIL COUNT DECREASED	3.0% 3/100 • Number of events 3 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations PLATELET COUNT DECREASED	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations WHITE BLOOD CELL COUNT DECREASED	3.0% 3/100 • Number of events 3 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	2.0% 2/100 • Number of events 2 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Metabolism and nutrition disorders HYPERGLYCAEMIA	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Metabolism and nutrition disorders HYPOALBUMINAEMIA	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Neoplasms benign, malignant and unspecified (incl cysts and polyps) FIBROADENOMA OF BREAST	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Neoplasms benign, malignant and unspecified (incl cysts and polyps) UTERINE LEIOMYOMA	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Psychiatric disorders ANXIETY	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Reproductive system and breast disorders BREAST PAIN	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Respiratory, thoracic and mediastinal disorders CHYLOTHORAX	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Respiratory, thoracic and mediastinal disorders INTERSTITIAL LUNG DISEASE	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Skin and subcutaneous tissue disorders RASH	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Vascular disorders EMBOLISM	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Vascular disorders HYPERTENSION	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.

Other adverse events

Measure	Arm A: Pertuzumab IV + Trastuzumab IV + Chemotherapy n=100 participants at risk Participants received 8 cycles of neoadjuvant chemotherapy: 4 cycles of doxorubicin plus cyclophosphamide (AC) once every 3 weeks (Q3W) followed by docetaxel Q3W for 4 cycles. Pertuzumab and trastuzumab were given intravenously (IV) for 4 cycles Q3W concurrently with the taxane component of chemotherapy. After completing their neoadjuvant therapy, participants underwent surgery. Thereafter, participants received an additional 14 cycles of pertuzumab IV and trastuzumab IV for a total of 18 cycles.	Arm B: Pertuzumab and Trastuzumab FDC SC + Chemotherapy n=100 participants at risk Participants received 8 cycles of neoadjuvant chemotherapy: 4 cycles of AC Q3W followed by docetaxel Q3W for 4 cycles. The pertuzumab and trastuzumab fixed-dose combination for subcutaneous administration (PH FDC SC) were given subcutaneously (SC) for 4 cycles (Q3W) concurrently with the taxane component of chemotherapy. After completing their neoadjuvant therapy, participants underwent surgery. Thereafter, participants received an additional 14 cycles of the PH FDC SC for a total of 18 cycles.
Blood and lymphatic system disorders ANAEMIA	63.0% 63/100 • Number of events 168 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	65.0% 65/100 • Number of events 156 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Blood and lymphatic system disorders FEBRILE NEUTROPENIA	4.0% 4/100 • Number of events 4 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	7.0% 7/100 • Number of events 8 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Blood and lymphatic system disorders LEUKOPENIA	25.0% 25/100 • Number of events 123 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	17.0% 17/100 • Number of events 103 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Blood and lymphatic system disorders NEUTROPENIA	9.0% 9/100 • Number of events 63 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	9.0% 9/100 • Number of events 50 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Gastrointestinal disorders ABDOMINAL PAIN UPPER	10.0% 10/100 • Number of events 13 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	7.0% 7/100 • Number of events 9 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Gastrointestinal disorders CONSTIPATION	10.0% 10/100 • Number of events 16 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	12.0% 12/100 • Number of events 23 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Gastrointestinal disorders DIARRHOEA	39.0% 39/100 • Number of events 93 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	27.0% 27/100 • Number of events 53 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Gastrointestinal disorders MOUTH ULCERATION	11.0% 11/100 • Number of events 16 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	14.0% 14/100 • Number of events 23 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Gastrointestinal disorders NAUSEA	48.0% 48/100 • Number of events 99 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	45.0% 45/100 • Number of events 97 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Gastrointestinal disorders STOMATITIS	7.0% 7/100 • Number of events 7 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	6.0% 6/100 • Number of events 11 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Gastrointestinal disorders TOOTHACHE	3.0% 3/100 • Number of events 4 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	6.0% 6/100 • Number of events 12 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Gastrointestinal disorders VOMITING	42.0% 42/100 • Number of events 80 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	46.0% 46/100 • Number of events 91 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
General disorders INFLUENZA LIKE ILLNESS	5.0% 5/100 • Number of events 6 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	6.0% 6/100 • Number of events 6 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
General disorders MALAISE	15.0% 15/100 • Number of events 28 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	12.0% 12/100 • Number of events 26 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
General disorders PYREXIA	15.0% 15/100 • Number of events 19 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	11.0% 11/100 • Number of events 22 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Infections and infestations UPPER RESPIRATORY TRACT INFECTION	8.0% 8/100 • Number of events 8 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	3.0% 3/100 • Number of events 4 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Infections and infestations URINARY TRACT INFECTION	6.0% 6/100 • Number of events 6 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	6.0% 6/100 • Number of events 7 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Injury, poisoning and procedural complications INFUSION RELATED REACTION	10.0% 10/100 • Number of events 14 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	2.0% 2/100 • Number of events 2 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations ALANINE AMINOTRANSFERASE INCREASED	39.0% 39/100 • Number of events 76 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	46.0% 46/100 • Number of events 71 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations ALPHA HYDROXYBUTYRATE DEHYDROGENASE INCREASED	5.0% 5/100 • Number of events 11 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	6.0% 6/100 • Number of events 11 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations ASPARTATE AMINOTRANSFERASE INCREASED	39.0% 39/100 • Number of events 76 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	38.0% 38/100 • Number of events 55 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations BLOOD ALKALINE PHOSPHATASE INCREASED	9.0% 9/100 • Number of events 13 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	12.0% 12/100 • Number of events 16 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations BLOOD CHOLESTEROL INCREASED	0.00% 0/100 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	5.0% 5/100 • Number of events 6 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations BLOOD CREATININE INCREASED	2.0% 2/100 • Number of events 5 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	7.0% 7/100 • Number of events 12 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations BLOOD LACTATE DEHYDROGENASE INCREASED	9.0% 9/100 • Number of events 20 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	8.0% 8/100 • Number of events 15 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations GAMMA-GLUTAMYLTRANSFERASE INCREASED	7.0% 7/100 • Number of events 10 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	8.0% 8/100 • Number of events 10 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations LYMPHOCYTE COUNT DECREASED	13.0% 13/100 • Number of events 25 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	14.0% 14/100 • Number of events 26 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations NEUTROPHIL COUNT DECREASED	59.0% 59/100 • Number of events 166 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	60.0% 60/100 • Number of events 190 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations PLATELET COUNT DECREASED	18.0% 18/100 • Number of events 51 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	21.0% 21/100 • Number of events 40 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations WEIGHT DECREASED	8.0% 8/100 • Number of events 9 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	8.0% 8/100 • Number of events 8 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Investigations WHITE BLOOD CELL COUNT DECREASED	46.0% 46/100 • Number of events 169 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	56.0% 56/100 • Number of events 208 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Metabolism and nutrition disorders DECREASED APPETITE	13.0% 13/100 • Number of events 33 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	11.0% 11/100 • Number of events 29 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Metabolism and nutrition disorders HYPERCHOLESTEROLAEMIA	2.0% 2/100 • Number of events 4 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	9.0% 9/100 • Number of events 11 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Metabolism and nutrition disorders HYPERGLYCAEMIA	9.0% 9/100 • Number of events 9 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	10.0% 10/100 • Number of events 18 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Metabolism and nutrition disorders HYPERTRIGLYCERIDAEMIA	12.0% 12/100 • Number of events 14 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	18.0% 18/100 • Number of events 43 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Metabolism and nutrition disorders HYPERURICAEMIA	10.0% 10/100 • Number of events 18 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	11.0% 11/100 • Number of events 20 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Metabolism and nutrition disorders HYPOALBUMINAEMIA	13.0% 13/100 • Number of events 21 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	13.0% 13/100 • Number of events 30 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Metabolism and nutrition disorders HYPOKALAEMIA	4.0% 4/100 • Number of events 6 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	6.0% 6/100 • Number of events 8 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Musculoskeletal and connective tissue disorders ARTHRALGIA	1.0% 1/100 • Number of events 1 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	7.0% 7/100 • Number of events 10 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Musculoskeletal and connective tissue disorders MYALGIA	8.0% 8/100 • Number of events 11 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	4.0% 4/100 • Number of events 7 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Musculoskeletal and connective tissue disorders PAIN IN EXTREMITY	3.0% 3/100 • Number of events 3 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	5.0% 5/100 • Number of events 10 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Nervous system disorders DIZZINESS	8.0% 8/100 • Number of events 12 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	4.0% 4/100 • Number of events 7 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Nervous system disorders HEADACHE	5.0% 5/100 • Number of events 7 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	2.0% 2/100 • Number of events 2 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Nervous system disorders HYPOAESTHESIA	6.0% 6/100 • Number of events 9 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	8.0% 8/100 • Number of events 10 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Psychiatric disorders INSOMNIA	2.0% 2/100 • Number of events 2 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	11.0% 11/100 • Number of events 14 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Respiratory, thoracic and mediastinal disorders COUGH	8.0% 8/100 • Number of events 9 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	13.0% 13/100 • Number of events 14 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Skin and subcutaneous tissue disorders ALOPECIA	58.0% 58/100 • Number of events 58 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	66.0% 66/100 • Number of events 66 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Skin and subcutaneous tissue disorders RASH	13.0% 13/100 • Number of events 20 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	15.0% 15/100 • Number of events 27 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.
Vascular disorders HYPERTENSION	3.0% 3/100 • Number of events 4 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.	5.0% 5/100 • Number of events 10 • From baseline until the primary completion date (up to approximately 1 year, 10 months) Adverse events (AEs) were analyzed for the safety analysis population, which included all participants who received at least one dose of study medication, according to the treatment actually received. One participant randomized to Arm A (IV) mistakenly received 1 SC injection of pertuzumab and trastuzumab FDC SC and was counted in Arm B (SC) for safety; total number analyzed in Arm A: 101-1=100, Arm B: 99+1=100. AEs are still being collected and will be updated within 1 year of study completion.

Additional Information

Medical Communications

Hoffmann-La Roche

Phone: 800-821-8590

Email: genentech@druginfo.com

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