Inclusion Criteria

DISEASE CHARACTERISTICS: Histologically confirmed asymptomatic, progressive, metastatic
adenocarcinoma of the prostate Progressive disease defined as increasing prostate-specific
antigen (PSA) levels from 2 measurements at least 2 weeks apart PSA greater than 5 ng/mL
Continued medical means of gonadal ablation (e.g., luteinizing hormone releasing hormone
(LHRH)) required No known CNS metastases unless previously treated by surgery or
radiotherapy and stable, asymptomatic, and not requiring steroids and anticonvulsants

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At
least 6 months Hematopoietic: Absolute neutrophil count at least 1,500/mm3 Platelet count
at least 100,000/mm3 Hemoglobin at least 8.5 g/Dl Hepatic: Bilirubin no greater than 1.5
times upper limit of normal (ULN) AST no greater than 3 times ULN (no greater than 5 times
ULN if liver metastases present) Serum cholesterol no greater than 350 mg/Dl Triglycerides
no greater than 300 mg/Dl Renal: Creatinine no greater than 1.5 times ULN Cardiovascular:
No unstable angina or life-threatening ventricular arrhythmia requiring maintenance
therapy No myocardial infarction within the past 6 months Other: No other malignancy in
past 5 years other than basal cell or squamous cell skin cancer HIV negative No active
infection Not immunocompromised No other major illness that would preclude study Fertile
patients must use effective contraception during and for 3 months after the study

PRIOR CONCURRENT THERAPY: Biologic therapy: Concurrent epoetin alfa allowed Chemotherapy:
No prior cytotoxic chemotherapy for prostate cancer No other concurrent chemotherapy
Endocrine therapy: See Disease Characteristics At least 6 weeks since prior antiandrogen
therapy At least 4 weeks since prior hormonal therapy (6 weeks for antiandrogens) for
prostate cancer other than continued LHRH agonist No concurrent systemic corticosteroids
No concurrent anticancer hormonal therapy Radiotherapy: At least 3 weeks since prior
radiotherapy No prior palliative radiotherapy to more than one site No prior strontium
chloride Sr 89 or samarium Sm 153 lexidronam pentasodium No concurrent radiotherapy
Surgery: At least 3 weeks since prior surgery Other: At least 4 weeks since prior
investigational agent No concurrent immunosuppressive agents No other concurrent
investigational agent No concurrent enzyme-inducing anticonvulsants (carbamazepine,
phenobarbital, phenytoin), ketoconazole, diltiazem, rifampin, terfenadine, cisapride,
astemizole, or pimozide No concurrent megestrol acetate for appetite Concurrent
bisphosphonates allowed