Comparison Study of MDX-010 (CTLA-4) Alone and Combined With Docetaxel in the Treatment of Patients With Hormone Refractory Prostate Cancer

Inclusion Criteria: * Clinical diagnosis of adenocarcinoma of the prostate. * Metastatic prostate cancer (positive bone scan or measurable disease). * Progressive disease after androgen deprivation. * No prior chemotherapy or immunotherapy (tumor vaccine, cytokine, or growth factor given to control prostate cancer). Exclusion Criteria: * Other prior malignancy, except for adequately treated basal or squamous cell skin cancer or superficial bladder cancer, or any other cancer from which the patient has been disease-free for greater than or equal to 5 years. * Previous occurrence of autoimmune disease. * Active infection requiring therapy including HIV or chronic hepatitis.