PRIOR CONCURRENT THERAPY: Biologic therapy: No prophylactic colony stimulating factors to prevent neutropenia No concurrent biologic therapy Chemotherapy: No more than 1 prior cytotoxic chemotherapy regimen No concurrent cytotoxic chemotherapy Endocrine therapy: See Disease Characteristics At least 6 weeks since prior peripheral antiandrogens (e.g., flutamide) No concurrent steroid therapy initiated within past 2 months Current LHRH agonist therapy should continue through study Radiotherapy: At least 4 weeks since prior radiotherapy (except low dose, non myelosuppressive) and recovered No prior irradiation to greater than 25% of bone marrow No prior strontium chloride Sr 89 or samarium Sm 153 lexidronam pentasodium No concurrent radiotherapy Surgery: See Disease Characteristics At least 4 weeks since prior major surgery and recovered No concurrent surgery Other: No other concurrent anticancer treatment At least 28 days since investigational drugs, including analgesics or antiemetics No other investigational drugs during and for 28 days after study No concurrent drugs that induce or inhibit CYP3A enzyme No concurrent herbal preparations (e.g., PC-SPES)