Neoadjuvant Ipilimumab in Prostate Cancer

The Study Drugs: Ipilimumab is designed to cause an immune response in your body by blocking 2 specific molecules that usually block an immune response. This may help to kill cancer cells. Leuprolide acetate is designed to lower the level of testosterone (a male hormone) in the blood. This may slow the growth of cancer cells. Study Drug Administration: If you are found to be eligible to take part in this study, you will receive a leuprolide acetate injection in your muscle. This is considered Week 0. One week later, you will begin treatment with ipilimumab. Ipilimumab will be given by vein over 90 minutes during Weeks 1 and 4 (about 21 days apart). During the infusion, your blood pressure will be measured every 30 minutes, and again an hour after you are finished receiving the drug. Study Visits: At Weeks 0, 1, 4 and 7, the following tests and procedures will be performed: * You will have a physical exam, including measurement of your vital signs and weight. * You will be asked about any drugs or treatments you may be receiving. * You will be asked about any side effects you may have experienced. * Your performance status will be recorded. * Blood (about 7-10 tablespoons) will be drawn for routine tests. This blood will also be tested to measure your protein, PSA and testosterone levels, to check the function of your thyroid and adrenal glands, and to test for an immune response. Surgery: About 4 weeks after your second treatment with ipilimumab, you will have surgery to remove your prostate gland. You will be asked to sign a separate consent form that describes the surgery and its risks. A sample of the leftover prostate gland tissue from surgery will be tested for an immune response. On that day, the following tests and procedures will be performed: Between 14 and 24 weeks after your surgery, you will return to the clinic for your post-operative follow-up visit. The following tests and procedures will be performed: * You will have a physical exam, including measurement of your vital signs and weight. * Your performance status will be recorded. * You will be asked about any drugs or treatments you may be receiving. * You will be asked about any side effects you have experienced since your last visit. * Blood (about 7-10 tablespoons) will be drawn for routine tests. This blood will also be used to measure your protein, testosterone and PSA levels, to check the function of your thyroid and adrenal glands, and to test for an immune response. * You will have a bone scan, and either a CT or MRI scan of your chest, abdomen, and pelvis to check the status of the disease. Length of Study: You will only receive 2 treatments with ipilimumab on this study. You will be on study until 24 weeks after surgery. You will be taken off study if intolerable side effects occur, if the disease gets worse, or if the study doctor thinks it is in your best interest to be taken off study. This is an investigational study. Ipilimumab is not FDA approved or commercially available. Ipilimumab is currently being used for research purposes only. Leuprolide acetate is FDA approved for management of metastatic prostate cancer but is not approved for use before definitive surgery. It is commercially available to treat prostate cancer. Up to 20 patients will take part in this study. All will be enrolled at MD Anderson.