Conditions: Breast Cancer
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 4804
Healthy volunteers: no

Brief summary:
This randomized, double-blind, placebo-controlled, two-arm study will assess the safety and efficacy of pertuzumab in addition to chemotherapy plus trastuzumab as adjuvant therapy in participants with operable HER2-positive primary breast cancer. This study will be carried out in collaboration with the Breast International Group (BIG).

Detailed description:

Arms:
arm 1: Participants will receive pertuzumab (840 mg loading dose, then 420 mg) and trastuzumab (8 mg/kg loading dose, then 6 mg/kg) intravenously (IV) every 3 weeks (Q3W) for 1 year (maximum 18 cycles) in combination with 1 of the following IV chemotherapy regimen (anthracycline-based or nonanthracycline-based) per Investigator's choice: 1) 3-4 cycles (Q3W) of 5-fluorouracil 500-600 mg/m\^2 + epirubicin 90-120 mg/m\^2 or doxorubicin 50 mg/m\^2 + cyclophosphamide 500-600 mg/m\^2 followed by either 3-4 cycles of docetaxel Q3W (100 mg/m\^2 for 3 cycles, 75 mg/m\^2 in first cycle and 100 mg/m\^2 in subsequent cycles, or 75 mg/m\^2 for 4 cycles) or 12 cycles of paclitaxel 80 mg/m\^2 once weekly (QW); 2) 4 cycles (Q3W) of doxorubicin 60 mg/m\^2 or epirubicin 90-120 mg/m\^2 + cyclophosphamide 500-600 mg/m\^2 followed by either 3-4 cycles of docetaxel Q3W or 12 cycles of paclitaxel QW (as described in Option 1); 3) 6 cycles (Q3W) of docetaxel 75 mg/m\^2 + carboplatin area under the curve (AUC) 6 (up to 900 mg). arm 2: Participants will receive placebo matching to pertuzumab IV Q3W and trastuzumab (8 milligrams per kilogram \[mg/kg\] loading dose, then 6 mg/kg) IV Q3W for 1 year (maximum 18 cycles) in combination with 1 of the following IV chemotherapy regimen (anthracycline-based or nonanthracycline-based) per Investigator's choice: 1) 3-4 cycles (Q3W) of 5-fluorouracil 500-600 milligrams per square meter (mg/m\^2) + epirubicin 90-120 mg/m\^2 or doxorubicin 50 mg/m\^2 + cyclophosphamide 500-600 mg/m\^2 followed by either 3-4 cycles of docetaxel Q3W (100 mg/m\^2 for 3 cycles, 75 mg/m\^2 in first cycle and 100 mg/m\^2 in subsequent cycles, or 75 mg/m\^2 for 4 cycles) or 12 cycles of paclitaxel 80 mg/m\^2 QW; 2) 4 cycles (Q3W) of doxorubicin 60 mg/m\^2 or epirubicin 90-120 mg/m\^2 + cyclophosphamide 500-600 mg/m\^2 followed by either 3-4 cycles of docetaxel Q3W or 12 cycles of paclitaxel QW (as described in Option 1); 3) 6 cycles (Q3W) of docetaxel 75 mg/m\^2 + carboplatin AUC 6 (up to 900 milligrams \[mg\]).

Interventions: intervention 1: 5-Fluorouracil intervention 2: Carboplatin intervention 3: Cyclophosphamide intervention 4: Docetaxel intervention 5: Doxorubicin intervention 6: Epirubicin intervention 7: Paclitaxel intervention 8: Pertuzumab intervention 9: Placebo intervention 10: Trastuzumab
Intervention descriptions: intervention 1: 5-Fluorouracil will be administered as per the schedule specified in the respective arm. intervention 2: Carboplatin will be administered as per the schedule specified in the respective arm. intervention 3: Cyclophosphamide will be administered as per the schedule specified in the respective arm. intervention 4: Docetaxel will be administered as per the schedule specified in the respective arm. intervention 5: Doxorubicin will be administered as per the schedule specified in the respective arm. intervention 6: Epirubicin will be administered as per the schedule specified in the respective arm. intervention 7: Paclitaxel will be administered as per the schedule specified in the respective arm. intervention 8: Pertuzumab will be administered as per the schedule specified in the respective arm. intervention 9: Placebo will be administered as per the schedule specified in the respective arm. intervention 10: Trastuzumab will be administered as per the schedule specified in the respective arm.

Protocol document: