Metformin Prostate Cancer Adjuvant Trial

Prostate cancer patients who have received treatment with radiation therapy or surgery, who have indicators of high-risk disease will be administered 750mg Metformin Extended Release twice per day for a period of 9 months. Metformin is an FDA-approved drug that is prescribed to treat high blood sugar levels in patients with Type 2 Diabetes. To track prostate cancer response in study participants, investigators will obtain prostate specific antigen (PSA) levels every three months for the duration of the trial.

Inclusion criteria

• Male > 18 years of age
• Biopsy confirmed adenocarcinoma of the prostate
• Able to swallow and retain oral medication
• Hemoglobin A1C <7.0%
• Able and willing to participate in the full 12 months of the study
• Able to understand instructions related to study procedures
• Able to read and write English

Exclusion criteria

• Metastatic Prostate Cancer
• Prostate Specific Antigen Doubling Time < 6 months
• Prior Chemotherapy, hormonal therapy, oral glucocorticoid therapy, Gonadotropin-releasing hormone analogue therapy
• Current or previous use of 5α-reductase inhibitors, antiandrogen drugs, metformin, oral or injectable diabetes drug
• Diagnosis of Type 1 Diabetes Mellitus
• Known hypersensitivity to metformin
• any condition associated with increased risk of metformin associated lactic acidosis
• participation in any investigational or marketed drug trial within 30 days prior to screening or during study period
• any unstable, serious co-existing medical conditions including but not limited to myocardial infarction, coronary bypass surgery, unstable angina, cardiac arrhythmias, clinically evident congestive heart failure, or cerebrovascular accident within 6 months prior to screening
• history of megaloblastic anemia
• abnormal liver function test (total bilirubin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase or serum creatinine above upper limit of normal)
• history of other malignancies, with the exception of adequately treated non-melanoma skin cancer, stage 1 melanoma, non-muscle invasive bladder cancer, or other solid tumors curatively treated with no evidence of disease for at least 5 years
• history or current evidence of substance abuse within 12 months of screening
• history of any illness (including psychiatric) that, in the opinion of the investigator, might confound the results of the study or post an additional risk to the subject