A Study of Trastuzumab-MCC-DM1 (T-DM1) in Combination With Pertuzumab Administered to Patients With HER2-Positive Locally Advanced or Metastatic Breast Cancer Who Have Previously Received Trastuzumab

Inclusion Criteria:

• Histologically documented HER2-positive locally advanced or metastatic breast cancer
• Tumor tissue blocks or 15-20 unstained tissue slides for confirmatory central laboratory HER2 status testing and other exploratory assessments
• Prior trastuzumab in any line of therapy
• No prior T-DM1 or pertuzumab therapy
• Measurable disease
• For women of childbearing potential, agreement to use an effective form of contraception and to continue its use for the duration of the study
• Life expectancy >= 90 days

Exclusion Criteria:

• Less than 21 days since the last anti-tumor therapy, including chemotherapy, biologic, experimental, immune, hormonal or radiotherapy for the treatment of breast cancer, with the following exceptions: hormone-replacement therapy or oral contraceptives; palliative radiation therapy involving =< 25% of marrow-bearing bone if administered >= 14 days prior to first study treatment
• History of intolerance or hypersensitivity to trastuzumab and/or adverse events related to trastuzumab that resulted in trastuzumab being permanently discontinued
• Peripheral neuropathy of Grade >= 2
• History of clinically significant cardiac dysfunction
• Current severe, uncontrolled systemic disease (e.g., clinically significant cardiovascular, pulmonary, or metabolic disease)
• Brain metastases that are untreated, progressive, or have required any type of therapy to control symptoms from brain metastases within 60 days of the first study treatment
• History of other malignancy within the last 5 years, except for appropriately treated carcinoma in situ of the cervix, non-melanoma skin carcinoma, or other malignancy with a similar expected curative outcome