Calcitriol in Combination With Ketoconazole and Therapeutic Hydrocortisone in Treating Patients With Prostate Cancer

PRIMARY OBJECTIVES: I. To determine the maximum tolerated dose (MTD) of oral calcitriol daily x 3 consecutive days a week in combination with oral ketoconazole (400 mg thrice daily \[TID\]) + oral hydrocortisone (20 mg AM, 10 mg PM) in men with androgen independent prostate cancer (AIPC). (Phase I) II. To estimate the prostate-specific antigen (PSA) response rate. (Phase II) SECONDARY OBJECTIVES: I. To evaluate the pharmacokinetics of the phase II dose of oral calcitriol with and without ketoconazole (400 mg TID). II. Describe any objective tumor responses to the combination of oral calcitriol and ketoconazole and hydrocortisone among patients with measurable disease using the Response Evaluation Criteria in Solid Tumors (RECIST) criteria. III. Determine toxicities and tolerability of oral calcitriol combination with daily oral ketoconazole and hydrocortisone. OUTLINE: This is a phase I, dose-escalation study of calcitriol followed by a phase II study. PHASE I: Patients receive calcitriol orally (PO) once daily (QD) on days 1-3, 8-10, 15-17, and 22-24. Patients also receive ketoconazole PO TID on days 1-24 and therapeutic hydrocortisone PO twice daily (BID) on days -1 to 24. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity. PHASE II: Patients receive calcitriol and therapeutic hydrocortisone as in phase I. Patients also receive ketoconazole PO TID on days 4-24. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up for 30 days.