A Research Study for Patients With Prostate Cancer

Inclusion Criteria: * Males ≥18 years; * Written informed consent/authorization; * Histological or cytological confirmation of metastatic prostate cancer with documented progression on hormonal therapy (objective progressive disease \[PD\], new bone lesions, or stable soft tissue or bone lesions with PSA increase); * Patients must have either measurable disease or bone metastasis. Patients with measurable disease are preferred; * Rising PSA, with a minimum study entry PSA of ≥5 ng/mL; * Karnofsky performance status of ≥80%; * Life expectancy of \>12 weeks; * For patients treated with anti-androgens, elevation of PSA must be demonstrated after cessation of anti-androgen treatment; * Three lines of hormonal therapy are permitted prior to study entry (anti-androgen withdrawal is not considered as a second hormonal treatment); * Serum testosterone level of \<50 ng/mL in patients without surgical castration; * Patients must have serum potassium levels \>4.0 mEq/L and serum magnesium levels \>2.0 mg/dL. Exclusion Criteria: * Concomitant use of any anti-cancer therapy, except for continued use of luteinizing hormone-releasing hormone (LHRH) agonists or antiandrogens, or bisphosphonates or steroids initiated at least 4 weeks prior to study entry; * Concomitant use of any investigational agent, including PC-SPES; * Use of any investigational agent within 4 weeks of study entry; * Concomitant use of warfarin (due to a potential drug-to-drug interaction with depsipeptide); * Major su…