DISEASE CHARACTERISTICS:

• Histologically confirmed prostate cancer

  • Metastatic androgen-independent disease

• Progression during hormonal ablation (e.g., luteinizing-hormone releasing-hormone [LHRH] agonist therapy) defined as at least 1 of the following:

  • Two consecutive rising PSA levels at least 1 week apart with at least 1 that is at least 50% above the nadir reached after the last therapy (must be at least 5 ng/mL)
  • At least 1 new metastatic deposit on technetium Tc 99m dextran bone scintigraphy
  • Progression of soft tissue metastases by imaging or palpation (development of new area of malignant disease or measurable disease progression)

• If no prior surgical castration, all of the following criteria must be met:

  • Concurrent LHRH agonist therapy
  • Concurrent gonadotropin-releasing hormone-agonist therapy
  • Testosterone less than 50 ng/mL
• No brain metastases

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• ECOG 0-2

Life expectancy:

• More than 3 months

Hematopoietic:

• Granulocyte count at least 1,500/mm^3
• Platelet count at least 100,000/mm^3

Hepatic:

• Bilirubin less than 1.0 mg/dL
• AST and ALT less than 2.5 times upper limit of normal (ULN)
• Alkaline phosphatase less than 2.5 times ULN

Renal:

• Creatinine no greater than 1.5 mg/dL OR
• Creatinine clearance at least 40 mL/min

Cardiovascular:

• No unstable or newly diagnosed angina pectoris
• No myocardial infarction within the past 6 months
• No New York Heart Association class II-IV heart disease

Other:

• Able to ingest oral medications
• No other active malignancy within the past 2 years except nonmelanoma skin cancer or carcinoma in situ of the bladder

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• Not specified

Endocrine therapy:

• See Disease Characteristics
• At least 4 weeks since prior flutamide
• At least 6 weeks since prior bicalutamide or nilutamide

Radiotherapy:

• No prior strontium chloride Sr 89 or samarium Sm 153 lexidronam pentasodium

Surgery:

• Recovered from prior surgery

Other:

• Recovered from prior therapy
• No concurrent combination antiretroviral therapy for HIV-positive patients
• No concurrent theophylline
• No concurrent cisapride
• No concurrent 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) inhibitors (e.g., lovastatin, atorvastatin, simvastatin, pravastatin, or cerivastatin)
• No concurrent known inhibitors and/or inducers of CYP3A4
• No concurrent terfenadine, midazolam, triazolam, alprazolam, astemizole, loratadine, rifampin, isoniazid, dofetilide, pimozide, sirolimus, or erythromycin
• No concurrent drugs that decrease gastric acid output or increase gastric pH (e.g., antacids, cimetidine, ranitidine, antimuscarinics, omeprazole, or lansoprazole)
• No concurrent warfarin