- History of anti-cancer therapy for MBC (with the exception of one prior hormonal regimen for MBC, which must be stopped prior to randomization) - History of approved or investigative tyrosine kinase/HER inhibitors for breast cancer in any treatment setting, except trastuzumab used in the neoadjuvant or adjuvant setting - History of systemic breast cancer treatment in the neo-adjuvant or adjuvant setting with a disease-free interval from completion of the systemic treatment (excluding hormonal therapy) to metastatic diagnosis of less than (<)12 months - History of persistent Grade ≥2 hematologic toxicity resulting from previous adjuvant therapy - Current peripheral neuropathy of National Cancer Institute-Common Terminology Criteria for Adverse Events (NCI-CTCAE) Version 3.0, Grade ≥3 at randomization - History of other malignancy within the last 5 years, except for carcinoma in situ of the cervix, basal cell carcinoma or squamous cell carcinoma