ESMO Virtual Congress 2020: Repurposing Metformin as Anticancer Drug: Preliminary Results of Randomized Controlled Trial in Advanced Prostate Cancer (MANSMED)

( Metformin is a biguanide agent which is commonly used in the first-line treatment of patients with type 2 diabetes. For many years, there has been an interest in its potential anti-cancer properties, particularly in prostate cancer. In observational studies, there has been a demonstrated association between the use of metformin and improved overall survival and reduction in the risk of developing castration-resistant disease.

In a mini-oral presentation at this year’s European Society of Medical Oncology (ESMO) 2020 Virtual Annual Meeting, Dr. Reham Alghandour presented the results of the MANSMED prospective randomized controlled trial. This trial recruited men with high-risk localized or metastatic hormone-sensitive prostate cancer. Patients were randomized in a 1:1 fashion to receive standard of care with combined androgen blockade using LHRH agonist and bicalutamide 50mg daily with or without metformin 850mg PO BID.


The primary study outcome was time to castrate-resistant prostate cancer and the secondary outcomes were overall survival and PSA response rate.

The authors recruited 124 of whom 62 were randomized to each of the intervention and control arms. Of a median follow-up of 18 months, 12 patients randomized to metformin died and 17 randomized to control disease.

In the assessment of the primary outcome, patients receiving metformin had a longer time to castration-resistant disease (median 29 months, 95% confidence interval 25 to 33) than those randomized to placebo (20 months, 95% confidence interval 16 to 24, p=0.01). This effect was most pronounced in men with high-risk localized disease and node-positive disease, marginal in those with low volume metastatic disease, and there was no benefit in those with high volume metastatic disease. There were no statistically significant differences in overall survival or PSA response rate. The only notable adverse event associated with administration of metformin was self-limited diarrhea.

Presented by: Reham Alghandour, PhD, Assistant Lecturer of Medical Oncology, Oncology Center Mansoura University, Mansoura, Egypt

Written by: Christopher J.D. Wallis, Urologic Oncology Fellow, Vanderbilt University Medical Center Contact: @WallisCJD on Twitter 2020 European Society for Medical Oncology Virtual Congress (#ESMO20), September 19th-September 21st, 2020.