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