Conditions: Breast Cancer
Allocation: NON_RANDOMIZED | Intervention model: PARALLEL
Enrollment: 213
Healthy volunteers: no

Brief summary:
This two-cohort, open-label, multicenter, phase 2 study will assess the safety and efficacy of pertuzumab given in combination with trastuzumab (Herceptin) and vinorelbine in first line participants with metastatic or locally advanced HER2-positive breast cancer. Participants will receive pertuzumab and trastuzumab administered sequentially as separate intravenous (IV) infusions (followed by vinorelbine) and conventional sequential administration of pertuzumab and trastuzumab in separate infusion bags, followed by vinorelbine.

Detailed description:

Arms:
arm 1: Pertuzumab will be administered as IV infusion on Day 1 of the first treatment cycle (1 cycle = 21 days) as a loading dose of 840 milligrams (mg), followed by 420 mg on Day 1 of each subsequent cycle. Trastuzumab will be administered as IV infusion on Day 2 of the first treatment cycle as a loading dose of 8 mg per kilogram (mg/kg), followed by 6 mg/kg on Day 2 of each subsequent cycle. Vinorelbine IV infusion (will be administered after trastuzumab) on Day 2 and Day 9 of the first treatment cycle at a dose of 25 mg per meter-squared (mg/m\^2) followed by 30-35 mg/m\^2 on Day 2 and Day 9 of each subsequent cycle. Pertuzumab and trastuzumab will be administered sequentially in separate infusion bags, followed by vinorelbine until disease progression, unacceptable toxicity, withdrawal of consent, death, or predefined study end (up to 47 cycles). arm 2: Pertuzumab will be administered as IV infusion on Day 1 of the first treatment cycle as a loading dose of 840 mg, followed by 420 mg on Day 1 of each subsequent cycle. Trastuzumab will be administered as IV infusion on Day 2 of the first treatment cycle as a loading dose of 8 mg/kg, followed by 6 mg/kg on Day 1 of each subsequent cycle. Vinorelbine IV infusion on Day 2 and Day 9 of the first treatment cycle at a dose of 25 mg/m\^2 followed by 30-35 mg/m\^2 on Day 1 and Day 8 of each subsequent cycle. If administration of all 3 drugs is well tolerated in Cycle 1, then on Day 1 of each subsequent cycle, pertuzumab 420 mg and trastuzumab 6 mg/kg will be administered in a single infusion bag, followed by vinorelbine until disease progression, unacceptable toxicity, withdrawal of consent, death, or predefined study end (up to 47 cycles).

Interventions: intervention 1: Pertuzumab intervention 2: Trastuzumab intervention 3: Vinorelbine
Intervention descriptions: intervention 1: Loading dose of 840 mg on Day 1 of first 21-day cycle, followed by 420 mg on Day 1 of each subsequent cycle. intervention 2: Loading dose of 8 mg/kg on Day 1 of first 21-day cycle, followed by 6 mg/kg on Day 1 or 2 of each subsequent cycle. intervention 3: A dose of 25 mg/m\^2 followed by 30-35 mg/m\^2 on Days 2 and 9 of the first 21-day cycle and on Days 1 and 8 (or Days 2 and 9) of each subsequent cycle.

Protocol document: