The main purpose of this study is to test the safety of trilostane by looking at what effects, good and bad, it has on patients with androgen-independent prostate cancer.

• Patients will take trilostane orally once a day for three days, then twice a day thereafter.
• Patients will complete a daily drug log recording the date, time and number of capsules taken.
• Trilostane may moderately decrease the production of steroids by the adrenal glands. In order to prevent any symptoms related to decreased steroid production, patients will also take hydrocortisone at the same time as the trilostane.
• While the patients are on treatment blood work will be done after 2 weeks and then every 4 weeks to test the levels of PSA in the blood. On weeks 4 and 8 of treatment additional blood work will be done to check hormone levels. Blood pressure and pulse rate will also be taken every 4 weeks.
• Depending upon disease status, radiological testing (CT scan, x-rays, and/or bone scan) may be repeated every 12 weeks.
• Patients will remain on study treatment as long as their disease responds and they do not experience any severe side effects.

Inclusion Criteria:

• Histologically confirmed prostate adenocarcinoma
• Disease progression despite androgen depravation therapy and antiandrogen withdrawal
• Progressive measurable disease or bone scan progression or PSA progression
• Serum total testosterone < 50ng/ml
• Creatinine < 2.0 mg/dl
• ALT < 2 x ULN
• CALGB performance status of 0,1, or 2

Exclusion Criteria:

• Radiation therapy within 4 weeks
• Antiandrogen within 8 weeks
• Other secondary hormonal therapy or investigational agents within 4 weeks
• Prior chemotherapy for androgen-independent prostate cancer
• History of adrenal insufficiency
• Known brain metastases
• Severe liver or renal disease