In a study published in the January 4th, 2014 issue of the journal, European Urology, Swiss researchers found that treatment with the anti-diabetic drug metformin in patients with hormone-resistant prostate cancer increased their progression-free survival and prolonged PSA doubling time. The one-year study included 44 men who were given 1,000 mg (1 gram) of metformin twice daily. After 12 weeks of treatment, 36% of patients were progression-free with over 25% of these men remaining progression-free at 24 weeks. Over 52% of the patients experienced a prolongation of PSA doubling time reflecting slower tumor growth. Additionally, insulin sensitivity markers improved by 26% in the first 12 weeks of treatment. The researchers concluded that treatment with metformin is safe in non-diabetic patients. Metformin’s low cost, favorable toxicity profile and positive effect on metabolic parameters warrants further investigation as a treatment for prostate cancer.