Study of Pralatrexate in Female Patients With Previously-treated Breast Cancer

This is an open label, multi-center, Phase 2 study of pralatrexate with vitamin B12 and folic acid supplementation in patients with advanced or metastatic breast cancer who have failed prior treatment(s). The start of study treatment is defined as the initiation of pralatrexate administration. Pralatrexate will be administered as an intravenous (IV) push over 3-5 minutes on days 1 and 15 (± 1 day at each time point) of a 4-week cycle (ie, every \[q\] 2 weeks). The initial dose of pralatrexate will be 190 mg/m2. Dose reduction to 150 mg/m2 with further reduction to 120 mg/m2 and 100 mg/m2 will be allowed for defined toxicity (see Section 7.3). If 100 mg/m2 is not tolerated, pralatrexate must be discontinued. Patients will receive vitamin supplementation consisting of vitamin B12, 1 mg intramuscular (IM) q 8-10 weeks and folic acid 1-1.25 mg by mouth (PO) once a day (QD). Patients must have received 1 mg vitamin B12 within 10 weeks prior to the initiation of pralatrexate and have received 7 days of 1-1.25 mg folic acid PO QD prior to the initiation of pralatrexate. Vitamin supplementation will continue throughout the study and for at least 30 days after the last administration of pralatrexate.