Repurposing metformin for cancer treatment: current clinical studies

// Young Kwang Chae 1,2,3 , Ayush Arya 3 , Mary-Kate Malecek 3 , Daniel Sanghoon Shin 4 , Benedito Carneiro 1,2,3 , Sunandana Chandra 1,2,3 , Jason Kaplan 1,2,3 , Aparna Kalyan 1,2,3 , Jessica K. Altman 1,2,3 , Leonidas Platanias 1,2,3,5 and Francis Giles 1,2,3 1 Northwestern Medicine Developmental Therapeutics Institute, Chicago, IL, USA 2 Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Chicago, IL, USA 3 Northwestern University Feinberg School of Medicine, Chicago, IL, USA 4 David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA 5 Division of Hematology-Oncology, Department of Medicine, Jesse Brown VA Medical Center, Chicago, IL, USA Correspondence to: Young Kwang Chae, email: // Keywords : metformin, clinical trials, cancer Received : September 20, 2015 Accepted : March 06, 2016 Published : March 19, 2016 Abstract In recent years, several studies have presented evidence suggesting a potential role for metformin in anti-cancer therapy. Preclinical studies have demonstrated several anticancer molecular mechanisms of metformin including mTOR inhibition, cytotoxic effects, and immunomodulation. Epidemiologic data have demonstrated decreased cancer incidence and mortality in patients taking metformin. Several clinical trials, focused on evaluation of metformin as an anti-cancer agent are presently underway. Data published from a small number of completed trials has put forth intriguing results. Clinical trials in pre-surgical endometrial cancer patients exhibited a significant decrease in Ki67 with metformin monotherapy. Another interesting observation was made in patients with breast cancer, wherein a trend towards improvement in cancer proliferation markers was noted in patients without insulin resistance. Data on survival outcomes with the use of metformin as an anti-cancer agent is awaited. This manuscript will critically review the role of metformin as a potential cancer treatment.