Inclusion Criteria

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed recurrent prostate
cancer No metastatic disease (pelvic lymph nodes are considered metastatic disease)
Surgically castrated OR Medically castrated (testosterone less than 50 ng/mL) Must
continue luteinizing hormone-releasing hormone (LHRH) analog therapy Biochemical
progression, defined by at least 2 consecutive rising PSA levels (at least 1 week apart)
over a prior reference value PSA at least 5 ng/mL

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: WHO 0-1 Life expectancy: At
least 6 months Hematopoietic: Neutrophil count at least 1,500/mm3 Platelet count at least
75,000/mm3 Hepatic: No concurrent unstable or uncompensated hepatic disease Bilirubin no
greater than 1.25 times upper limit of normal (ULN) ALT or AST no greater than 2.5 times
ULN Renal: No concurrent unstable or uncompensated renal disease Creatinine no greater
than 2 times ULN Cardiovascular: No concurrent unstable or uncompensated cardiac disease
Pulmonary: No concurrent unstable or uncompensated respiratory disease Other: Fertile
patients must use effective contraception No concurrent ocular inflammation or infection
No new neurologic symptoms or signs consistent with acute or evolving spinal cord
compression confirmed by MRI No other severe or uncontrolled systemic disease No other
significant clinical disorder or laboratory finding that would preclude study No blood
donation during and for 3 months after study

PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent biologic therapy except epoetin
alfa Chemotherapy: No prior chemotherapy for recurrent prostate cancer No concurrent
suramin Endocrine therapy: See Disease Characteristics At least 8 weeks since prior
bicalutamide or nilutamide At least 4 weeks since prior flutamide At least 4 weeks since
prior megestrol or corticosteroids No prior estramustine for recurrent prostate cancer No
concurrent anticancer hormonal therapy except LHRH analog therapy for medically castrated
patients Radiotherapy: At least 4 weeks since prior radiotherapy No concurrent
radiotherapy Surgery: See Disease Characteristics Recovered from prior oncologic or other
major surgery No surgery during or for 1 week after study Other: Recovered from prior
anticancer therapy At least 4 weeks since prior ketoconazole, PC-SPES, or saw palmetto No
concurrent systemic retinoids No other concurrent anticancer therapy or investigational
agents (e.g., coenzyme Q-10, PC-SPES, or saw palmetto) Concurrent intravenous
bisphosphonates allowed if initiated before study