Inclusion Criteria

DISEASE CHARACTERISTICS: Histologically confirmed adenocarcinoma of the prostate with
progressive systemic disease despite at least 1 endocrine manipulation including 1 of the
following: Orchiectomy LHRH analogue with or without flutamide, megestrol, or
diethylstilbestrol Flutamide must be discontinued for at least 2 weeks with PSA stabilized
above normal or rising Measurable or evaluable disease No brain metastasis

PATIENT CHARACTERISTICS: Age: Not specified Performance status: ECOG 0-2 Life expectancy:
Greater than 2 months Hematopoietic: Granulocyte count at least 1,500/mm3 Platelet count
at least 100,000/mm3 Hepatic: Bilirubin greater than 1 mg/dL SGOT greater than 2 times
upper limit of normal Renal: Creatinine less than 2 mg/dL Hydronephrosis with impaired
renal function must be decompressed adequately Cardiovascular: No severe cardiac (i.e.,
symptomatic arrhythmia requiring medication or active congestive heart failure) or
coronary disease that are unstable despite medication Other: Adequate nutritional status
(at least 1,500 Kcal/day) No other significant active medical illness that would preclude
study therapy or survival No other malignancy within the past 5 years except adequately
treated basal or squamous cell carcinoma of the skin No acute spinal cord compression

PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent biologic response modifiers
Chemotherapy: No other concurrent chemotherapy Endocrine therapy: See Disease
Characteristics At least 2 weeks since prior corticosteroids No concurrent exogenous
corticosteroids except for documented CNS metastases or adrenal insufficiency Concurrent
hormones for nondisease conditions allowed (e.g., insulin for diabetes mellitus)
Concurrent continuation of monthly hormonal therapy with an LHRH agonist or DES required
Radiotherapy: Prior radiation to symptomatic metastatic site allowed provided it is not
the only measurable or evaluable lesion At least 2 weeks since prior radiotherapy and
recovered No concurrent radiotherapy No concurrent palliative radiotherapy except for
whole brain irradiation for documented CNS disease or impending spinal cord compression
Surgery: See Disease Characteristics At least 3 weeks since prior surgery and recovered
Other: No other concurrent treatment for prostate cancer except pain palliation