Safety and Efficacy Study of a New Chemotherapy Agent to Treat Metastatic Breast Cancer

16 mg/m2, 3-hour i.v. infusion, 1 cycle every 3 weeks. Planned number of cycles : 2-6.

12 mg/m2, 3-hour i.v. infusion, 1 cycle every 3 weeks. Planned number of cycles : 2-6.

22 mg/m2, 30-minute i.v. infusion, 1 cycle every 3 weeks. Planned number of cycles : 2-6.

22 mg/m2, 3-hour i.v. infusion, 1 cycle every 3 weeks. Planned number of cycles : 2-6.