DISEASE CHARACTERISTICS:

• Histologically confirmed prostate cancer

  • Metastatic disease

  • Progressive, androgen-independent disease

    • Radiographic evidence of disease that has continued to progress despite hormonal agents

      • Patients on flutamide must have disease progression at least 4 weeks after withdrawal
      • Patients on bicalutamide or nilutamide must have disease progression at least 6 weeks after withdrawal
    • Progressive disease requires that a measurable lesion is expanding, new lesions have appeared, and/or that prostate-specific antigen is continuing to rise on successive measurements
• Must have received prior docetaxel for androgen-independent prostate cancer
• Concurrent gonadotropin-releasing hormone agonists or antagonists required for patients without bilateral surgical castration
• No known brain metastases

PATIENT CHARACTERISTICS:

• ECOG performance status (PS) 0-2 Karnofsky PS 60-100%
• Life expectancy > 3 months
• Absolute neutrophil count ≥ 1,500/mm^3
• Platelet count ≥ 100,000/mm^3
• Hemoglobin ≥ 8 g/dL
• Bilirubin ≤ 1.5 times upper limit of normal (ULN) (unless due to clinical Gilbert's syndrome)
• AST and ALT ≤ 2.5 times ULN
• Creatinine ≤ 1.5 times ULN OR creatinine clearance > 40 mL/min
• Urine protein ≤ +1 on two consecutive dipsticks taken no less than 1 week apart
• Blood pressure < 140/90 mm Hg
• Fertile patients must use effective contraception during and for 3 months after completion of study participation
• No other invasive malignancies within the past 5 years except nonmelanoma skin cancer or noninvasive bladder cancer
• No mean QTc > 470 msec (with Bazett's correction)
• No history of familial long QT syndrome

• No uncontrolled intercurrent illness including, but not limited to, any of the following:

  • Hypertension
  • Ongoing or active infection
  • Symptomatic congestive heart failure
  • Unstable angina pectoris
  • Cardiac arrhythmia
  • Psychiatric illness or social situation that would limit compliance

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics
• Recovered from prior therapy, including surgery
• At least 4 weeks since prior agents not approved by the FDA
• At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin C), radiotherapy, or major surgery
• Concurrent bisphosphonates allowed for patients with known bone metastases
• No concurrent grapefruit juice
• No concurrent antiretroviral therapy for HIV-positive patients
• No other concurrent anticancer agents or therapies