PRIOR CONCURRENT THERAPY: Biologic therapy: At least 4 weeks since prior biologic response modifiers At least 4 weeks since prior immunotherapy No concurrent immunotherapy Chemotherapy: No prior SU101 or mitoxantrone No prior cytotoxic chemotherapy for prostate cancer No other concurrent chemotherapy Endocrine therapy: See Disease Characteristics At least 4 weeks since prior antiandrogen therapy and recovered Concurrent primary androgen ablation therapy (orchidectomy, luteinizing hormone releasing hormone (LHRH) agonist (if stable dose), estrogen, or cyproterone acetate) allowed No concurrent antiandrogen therapy (except LHRH) No concurrent cholestyramine Radiotherapy: At least 4 weeks since prior radiotherapy (8 weeks since strontium 89 and samarium 153) Prior palliative radiotherapy to metastatic sites allowed No prior radiotherapy to greater than 50% of bone marrow No concurrent radiotherapy except for palliation of bone pain Surgery: At least 2 weeks since prior major surgery No concurrent surgery for prostate cancer Other: At least 4 weeks since prior investigational therapy At least 4 weeks since prior antiangiogenesis therapy At least 6 weeks since prior bicalutamide No other concurrent investigational therapy