PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent immunotherapy Chemotherapy: At least 4 weeks since prior chemotherapy and recovered Endocrine therapy: Concurrent medical therapy (i.e., gonadotropin releasing hormone analogs or diethylstilbestrol) to maintain castrate levels of serum testosterone allowed No other concurrent hormonal therapy Radiotherapy: At least 4 weeks since prior radiotherapy and recovered Concurrent radiotherapy to localized sites of disease not being evaluated in study allowed Surgery: Not specified Other: At least 4 weeks since prior investigational anticancer therapy and recovered No concurrent intravenous antibiotics