Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically or cytologically confirmed adenocarcinoma of the prostate

- PSA at least 20 ng/mL at study entry

- Must have documented evidence of disease progression, defined by 1 of the following
conditions:

- Rising PSA documented after discontinuation of peripheral antiandrogens

- Minimum evidence of progression is a 25% increase in PSA over the reference
value, provided that the increase is at least 5 ng/mL

- Must have a first increase in PSA documented at least 1 week after the
reference value and a second increase in PSA documented at least 1
week after the first increase

- Progressive measurable disease during androgen ablative therapy (including
medical or surgical castration)

- Castrate level (no greater than 50 ng/mL) of testosterone required if receiving
medical androgen-ablative therapy at study entry

- Concurrent luteinizing hormone-releasing hormone agonist therapy required if
receiving this medication at study entry

PATIENT CHARACTERISTICS:

Age:

- 16 and over

Performance status:

- ECOG 0-1

Life expectancy:

- Not specified

Hematopoietic:

- Absolute granulocyte count at least 1,500/mm3

- Platelet count at least 100,000/mm3

Hepatic:

- Bilirubin no greater than 2 times upper limit of normal (ULN)

- AST/ALT no greater than 2.5 times ULN (5 times ULN if documented liver metastases)

Renal:

- Creatinine no greater than 2 times ULN

Other:

- No other malignancy within the past 5 years

- No active uncontrolled bacterial, fungal, or viral infection

- No significant neurological disorder that would preclude informed consent

- No other serious illness or medical condition that would preclude study

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- Concurrent epoetin alfa allowed

Chemotherapy:

- No prior chemotherapy

- No concurrent cytotoxic therapy

Endocrine therapy:

- See Disease Characteristics

- At least 4 weeks since prior peripheral antiandrogens (6 weeks for bicalutamide)

- Concurrent steroids allowed if on stable dose for at least 4 weeks before study and
no dose increase planned

Radiotherapy:

- At least 4 weeks since prior radiotherapy except low-dose, nonmyelosuppressive
radiotherapy approved by the National Cancer Institute of Canada, Clinical Trials
Group

Surgery:

- See Disease Characteristics

- No concurrent ophthalmic surgery

Other:

- No prior investigational agents

- No other concurrent investigational therapy

- No concurrent ketoconazole

- No concurrent high-dose narcotic therapy for pain (e.g., morphine equivalent dose
more than 60 mg/day)

- Concurrent bisphosphonates allowed