Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed androgen independent metastatic prostate cancer

- Progressive disease manifested by either:

- New osseous lesions by bone scan or a greater than 25% increase in
bidimensionally measurable soft tissue disease or the appearance of new sites of
disease by MRI or CT scan OR

- Minimum of 3 rising PSA values from baseline that are obtained 1 week or more
apart, or 2 rising PSA values more than 1 month apart, where the percentage
increase over the range of values is at least 25%

- Castrate state by orchiectomy or gonadotropin-releasing hormone analogues for minimum
of 1 year

- Testosterone no greater than 30 ng/mL

- Measurable disease

- Metastatic disease by bone scan, MRI, or CT scan

- Rising PSA values

- If receiving antiandrogen therapy, must have shown progressive disease off treatment

- No active CNS or epidural tumor

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Performance status:

- Karnofsky 60-100%

Life expectancy:

- Not specified

Hematopoietic:

- WBC at least 3,500/mm^3

- Platelet count greater than 100,000/mm^3

Hepatic:

- Bilirubin less than 2.0 mg/dL

- SGOT less than 3 times upper limit of normal

- PTT less than 14 seconds

Renal:

- Creatinine less than 2.0 mg/dL OR

- Creatinine clearance greater than 60 mL/min

Cardiovascular:

- No New York Heart Association class III or IV cardiac disease

Pulmonary:

- No severe debilitating pulmonary disease

Other:

- No infection requiring IV antibiotics

- No other severe medical problems that would increase risk for toxicity

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- Recovered from prior biologic therapy

- No concurrent immunotherapy

Chemotherapy:

- Recovered from prior chemotherapy

- No concurrent chemotherapy

Endocrine therapy:

- See Disease Characteristics

- If no prior orchiectomy, must continue on gonadotropin-releasing hormone analogs to
maintain castrate levels of testosterone

- No concurrent finasteride

- No other concurrent hormonal therapy

Radiotherapy:

- Recovered from prior radiotherapy

- No concurrent radiotherapy to an indicator lesion

Surgery:

- See Disease Characteristics

- Recovered from prior surgery

- No concurrent surgery on only measurable lesion

Other:

- At least 4 weeks since other prior investigational anticancer drugs and recovered

- No other concurrent investigational anticancer agents