Inclusion Criteria

DISEASE CHARACTERISTICS:

- Diagnosis of stage IVA or IVB hormone-refractory prostate cancer

- Evidence of metastatic disease by physical exam, bone scan, abdominal or pelvic
CT scan, or chest X-ray

- Must have failed at least 2 prior hormonal therapy regimens (e.g., luteinizing
hormone-releasing hormone [LHRH] agonist plus antiandrogen and antiandrogen
withdrawal)

- Must have 2 successive increases in serum prostate-specific antigen (PSA) levels
to at least 10 ng/mL measured at least 2 weeks apart

- Must have castrate testosterone levels (no greater than 50 ng/dL) due to prior
orchiectomy or continuing LHRH agonist therapy

- Obstructive uropathy and/or hydronephrosis allowed if adequate renal function and
urinary drainage

PATIENT CHARACTERISTICS:

Age:

- Any age

Performance status:

- ECOG 0-2

Life expectancy:

- Not specified

Hematopoietic:

- WBC at least 2,500/mm^3

- Absolute neutrophil count at least 1,500/mm^3

- Platelet count at least 100,000/mm^3

- Hemoglobin at least 9.0 g/dL

Hepatic:

- Bilirubin less than 2 mg/dL

- Transaminases less than 2.5 times upper limit of normal

Renal:

- See Disease Characteristics

- Creatinine less than 2 mg/dL

- Potassium between 4.0 and 5.5 mEq/L OR

- Magnesium between 1.5 and 2.5 mEq/L

Cardiovascular:

- No second-degree heart block without permanent pacemaker

- QT interval under 500 milliseconds

Other:

- No significant active infectious disease

- No grade 2 or greater peripheral neuropathy

- No other debilitating acute or chronic co-morbid medical, neurological, or
psychiatric condition that would preclude study compliance

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- Not specified

Chemotherapy:

- At least 4 weeks since prior chemotherapy (6 weeks for mitomycin or nitrosoureas and
8 weeks for suramin) and recovered

Endocrine therapy:

- See Disease Characteristics

- At least 4 weeks since prior antiandrogen therapy (6 weeks for bicalutamide) (if PSA
is increased from baseline)

- At least 2 weeks since prior corticosteroid therapy and recovered

Radiotherapy:

- At least 2 weeks since prior radiotherapy (4 weeks for strontium chloride Sr 90) and
recovered

Surgery:

- See Disease Characteristics

- Recovered from prior surgery

Other:

- Recovered from acute toxicity of prior therapy

- At least 3 weeks since prior bisphosphonates

- No concurrent amphotericin B or other agent that prevents restoration of potassium or
magnesium to normal levels and/or correction of QT interval to under 500 milliseconds