Study of Metformin With Simvastatin for Men With Prostate Carcinoma

Men who participate in this study will take both metformin and simvastatin every day. Both drugs are pills and can be taken at home. Subjects will be asked to take metformin and simvastatin until metastasis from their prostate cancer appears or until their PSA has doubled from what it was before they started the study. Primary Objective: To define the efficacy, as measured by an improvement in PSA doubling time (PSADT) at 6 months, of the combination of metformin plus simvastatin in patients with recurrent prostate cancer following definitive treatment. Secondary Objectives: 1. To define the time to protocol-specified event for men treated with the combination of metformin plus simvastatin. 2. To describe the pattern of change in log PSA levels and PSA velocity over time during treatment with metformin plus simvastatin. 3. To describe the associations between changes in metabolic parameters (fasting glucose/insulin/lipid panel/leptin/adiponectin and others) with the pattern of change in log PSA levels.