Vaccine Therapy With PROSTVAC/TRICOM and Flutamide Versus Flutamide Alone to Treat Prostate Cancer

Background: * Flutamide is an approved drug for prostate cancer that blocks the effects of testosterone on prostate cancer cells and may slow the progression of the disease. * The vaccine in this study consists of a priming vaccine called PROSTVAC (rilimogene galvacirepvec/rilimogene glafolivec) -V/TRICOM (triad of costimulatory molecules), made from vaccinia virus, and a boosting vaccine called PROSTVAC-F/TRICOM, made from fowlpox virus. DNA (Deoxyribonuceic acid) is inserted into the priming and boosting vaccine viruses to cause production of proteins that enhance immune activity and also to produce prostate specific antigen (PSA) a protein that is normally produced by the patients tumor cells. * GM-CSF (granulocyte macrophage colony stimulating factor), given along with the vaccine, is a chemical that boosts the immune system. It is used in this study to try to increase the usefulness of the vaccine by increasing the number of immune cells at the vaccination site. Objectives: -To determine if treatment with a prostate cancer vaccine plus flutamide is more effective than flutamide alone in delaying disease progression in patients with prostate cancer. Eligibility: * Patients 18 years of age and older with androgen-insensitive prostate cancer that has not spread beyond the prostate gland. * Patients with a rising PSA (prostatic specific antigen) who have already been treated with anti-iandrogen therapy (either bicalutamide or nilutamide). Design: * There are two treatment groups in this study. Group A receives only flutamide; group B receive flutamide plus vaccine. * Patients in both groups receive flutamide by mouth three times a day. * Patients in group B receive PROSTVAC-V/TRICOM on day 1 and PROSTVAC-F/TRICOM on day 29 and again every 4 weeks. All vaccines are given as injections under the skin. * Patients have blood tests for PSA levels every month and scans every 3 months until the disease worsens. * After 3 months of therapy, patients receiving in gro