DISEASE CHARACTERISTICS:

• Histologically confirmed adenocarcinoma of the prostate with progressing regional or metastatic disease despite primary hormonal therapy (bilateral orchiectomy, estrogen, or luteinizing hormone-releasing hormone (LHRH) therapy with or without simultaneous antiandrogen)
• Documented new lesions or rising PSA (at least 50% increase on 3 measurements more than 2 weeks apart) after prior antiandrogen or progestational agent, or other hormonal agent cessation

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• ECOG 0-2

Life expectancy:

• Not specified

Hematopoietic:

• WBC greater than 3,500/mm^3
• Absolute neutrophil count greater than 1,500/mm^3
• Platelet count greater than 100,000/mm^3

Hepatic:

• Bilirubin less than 2.0 mg/dL
• SGOT less than 4 times upper limit of normal

Renal:

• Creatinine no greater than 1.8 mg/dL

Other:

• No uncontrolled diabetes mellitus
• Fertile patients must use effective double barrier contraception for at least 1 week before, during, and at least 2 weeks after study participation

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Concurrent epoetin alfa for anemia allowed

Chemotherapy:

• Not specified

Endocrine therapy:

• See Disease Characteristics
• At least 28 days since prior antiandrogens or progestational agents
• Concurrent testicular androgen suppression with an LHRH analog (leuprolide or goserelin) allowed in non-orchidectomized patients

Radiotherapy:

• No concurrent radiotherapy

Surgery:

• Not specified

Other:

• No concurrent bisphosphonates