Percentage of Participants Who Died, Final Overall Survival Analysis

Pertuzumab + Trastuzumab + Chemotherapy

Participants received pertuzumab (840 mg loading dose, then 420 mg) and trastuzumab (8 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 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 area under the curve (AUC) 6 (up to 900 mg).

Placebo + Trastuzumab + Chemotherapy

Participants received placebo matched to pertuzumab IV Q3W and trastuzumab (8 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 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 mg).

Analysis denominator · Participants

1. ci Lower Limit

   0.69

   ci Num Sides

   TWO_SIDED

   ci Pct Value

   95

   ci Upper Limit

   1.00

   estimate Comment

   Hazard ratio was estimated by Cox regression.

   group Description

   Analysis was performed using stratified log-rank test, which included nodal status, protocol version, central hormone receptor status, and adjuvant chemotherapy regimen as stratification factors in the randomization.

   group Ids

   1. OG000
   2. OG001

   non Inferiority Type

   SUPERIORITY

   p Value

   0.0441

   p Value Comment

   The p-value threshold according to the alpha-spending function at this final analysis was 0.0496.

   param Type

   Hazard Ratio (HR)

   param Value

   0.83

   statistical Method

   Log Rank