A Study to Assess Efficacy and Safety of Pertuzumab Given in Combination With Trastuzumab and Vinorelbine in Participants With Metastatic or Locally Advanced Human Epidermal Growth Factor Receptor (HER) 2-Positive Breast Cancer

A Two-cohort, Open-label, Multicenter Phase II Trial Assessing the Efficacy and Safety of Pertuzumab Given in Combination With Trastuzumab and Vinorelbine in First Line Patients With HER2-positive Advanced (Metastatic or Locally Advanced) Breast Cancer

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.

Inclusion Criteria:

• Histologically or cytologically confirmed and documented adenocarcinoma of the breast with metastatic or locally advanced disease not amenable to curative resection
• HER2-positive as assessed by local laboratory on primary or metastatic tumor
• At least one measurable lesion and/or non-measurable disease evaluable according to RECIST v1.1 criteria
• Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1
• Left ventricular ejection fraction (LVEF) of at least 55%
• Life expectancy of at least 12 weeks

Exclusion Criteria:

• Previous systemic non-hormonal anti-cancer therapy in the metastatic or locally advanced breast cancer setting
• Previous approved or investigative anti-HER2 agents in any breast cancer treatment setting, except trastuzumab and/or lapatinib in the adjuvant or neoadjuvant setting
• Disease progression while receiving trastuzumab and/or lapatinib in the adjuvant or neoadjuvant setting
• Disease-free interval from completion of adjuvant or neoadjuvant systemic non-hormonal treatment to recurrent disease of less than 6 months
• History of persistent Grade 2 or higher (National Cancer Institute Common Terminology Criteria [NCI-CTC], Version 4.0) hematological toxicity resulting from previous adjuvant or neoadjuvant therapy
• Radiographic evidence of central nervous system metastases that are not well controlled with local therapy (irradiation or surgery)
• Current peripheral neuropathy of NCI-CTC, version 4.0 Grade 3 or greater
• History of other malignancy within the last 5 years, except for carcinoma in situ of the cervix, non-melanoma skin carcinoma, Stage 1 uterine cancer, or cancers with a similar curative outcome as those mentioned above
• Serious uncontrolled concomitant disease that would contraindicate the use of any of the investigational drugs used in this study or would put the participants at high risk for treatment-related complications
• Inadequate hematologic, liver, or renal function
• Uncontrolled hypertension or clinically significant cardiovascular disease
• Hepatitis B, hepatitis C, or human immunodeficiency virus (HIV) infection
• Current chronic daily treatment with corticosteroids (>/= 10 mg/day methylprednisolone or equivalent), excluding inhaled steroids