Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed metastatic adenocarcinoma of the prostate

- Unresponsive or refractory to hormonal therapy, as defined by at least 1 of the
following criteria:

- Progression of bidimensionally measurable disease

- Progression of evaluable but not measurable disease (bone scan)

- At least 2 consecutive rises in PSA and a PSA level of at least 5 ng/mL

- No minimum PSA required for measurable disease or non-PSA evaluable disease

- Soft tissue disease that has been irradiated within the past 2 months is not
considered measurable disease

- Prior orchiectomy OR

- Medical castration using leuprolide or goserelin

- LHRH agonist therapy must continue during study

- Prior nonsteroidal antiandrogens (flutamide, ketoconazole, bicalutamide, or
nilutamide) allowed if disease progression occurred

- No third-space fluid accumulation such as ascites or symptomatic pleural effusion

- No brain metastases

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Performance status:

- SWOG 0-3

- Performance status 3 must be due to pain secondary to bone metastases

Life expectancy:

- Not specified

Hematopoietic:

- No hypercoagulability

Hepatic:

- Not specified

Renal:

- Creatinine no greater than 2.0 mg/dL

Cardiovascular:

- No history of myocardial infarction

- No history of congestive heart failure unless well controlled

- No history of cerebrovascular accident or atrial fibrillation

- No active thrombophlebitis

- LVEF at least 50% by MUGA scan or 2-D echocardiogram

Pulmonary:

- No history of pulmonary embolus

Other:

- Recovered from major infections

- No other significant active medical illness

- No other malignancy within the past 5 years except adequately treated basal cell or
squamous cell skin cancer or stage I or II cancer currently in complete remission

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- At least 4 weeks since prior biologic therapy and recovered

- No more than 1 prior biologic therapy regimen

- No concurrent biological response modifiers

Chemotherapy:

- At least 4 weeks since prior chemotherapy and recovered

- No more than 1 prior chemotherapy regimen

- No prior estramustine, taxanes, anthracyclines, or mitoxantrone

- No other concurrent chemotherapy

Endocrine therapy:

- See Disease Characteristics

- At least 4 weeks since prior flutamide or ketoconazole (6 weeks for bicalutamide or
nilutamide)

- No concurrent corticosteroids or hormonal therapy (except megestrol for hot flashes
or continuing LHRH treatment)

Radiotherapy:

- See Disease Characteristics

- Prior samarium Sm 153 lexidronam pentasodium allowed

- At least 4 weeks since prior radiotherapy and recovered

- No prior radiotherapy to 30% or more of bone marrow

- No prior strontium chloride Sr 89

- No concurrent radiotherapy

Surgery:

- See Disease Characteristics

- At least 3 weeks since prior surgery and recovered

Other:

- At least 4 weeks since prior bisphosphonates

- No prior anticoagulation therapy (i.e., warfarin), except aspirin

- No concurrent bisphosphonates