PRIOR CONCURRENT THERAPY: Biologic therapy: Recovered from prior biologic therapy Chemotherapy: At least 4 weeks since prior chemotherapy and recovered Endocrine therapy: Recovered from prior endocrine therapy Radiotherapy: At least 4 weeks since prior radiotherapy and recovered No concurrent radiotherapy to target lesions Surgery: Not specified Other: At least 4 weeks since other prior investigational anticancer drugs and recovered No concurrent ketoconazole in patients with prostate cancer