1. Subjects must not have had more than 1 prior chemotherapy regimen for metastatic disease and no chemotherapy within 3 weeks prior to randomization. 2. No concurrent chemotherapy is allowed while on protocol therapy. Subjects whose adjuvant hormonal therapy was discontinued more than 12 months ago must have had only 1 prior hormonal therapy for metastatic disease. Subjects who relapsed while receiving adjuvant hormonal therapy or less than 12 months after completing adjuvant hormonal therapy may be enrolled directly in the trial.