- First-line locally advanced and/or metastatic breast cancer with no prior adjuvant chemotherapy unless the Investigator determines that one of the 4 cytotoxic chemotherapy agents in the control arm would otherwise be offered to the subject - Prior treatment with a PARP inhibitor (not including iniparib) - Not a candidate for treatment with at least 1 of the treatments of protocol-specific physician's choice (ie, capecitabine, eribulin, gemcitabine, vinorelbine) - Subjects who had objective disease progression while receiving platinum chemotherapy administered for locally advanced or metastatic disease; subjects who received low-dose platinum therapy administered in combination with radiation therapy are not excluded - Subjects who have received platinum in the adjuvant or neoadjuvant setting are eligible; however, subjects may not have relapsed within 6 months of the last dose of prior platinum therapy - Cytotoxic chemotherapy within 14 days before randomization - Radiation or anti-hormonal therapy or other targeted anticancer therapy within 14 days before randomization - HER2 positive breast cancer - Active inflammatory breast cancer - CNS metastases • Exception: Adequately treated brain metastases documented by baseline CT or MRI scan that has not progressed since previous scans and that does not require corticosteroids (except prednisone ≤5 mg/day or equivalent) for management of CNS symptoms. A repeat CT or MRI following the identification of CNS metastases (obtained at least 2 weeks after definitive therapy) must document adequately treated brain metastases. • Subjects with leptomeningeal carcinomatosis are not permitted Prior malignancy except for any of the following: • Prior BRCA-associated cancer as long as there is no current evidence of the cancer • Carcinoma in situ or non-melanoma skin cancer • A cancer diagnosed and definitively treated ≥5 years before randomization with no subsequent evidence of recurrence - Known to be human immunodeficiency virus positive - Known active hepatitis C virus, or known active hepatitis B virus - Known hypersensitivity to any of the components of talazoparib