Is it still worth pursuing the repurposing of metformin as a cancer therapeutic?

Over the past 15 years, there has been great interest in the potential to repurpose the diabetes drug, metformin, as a cancer treatment. However, despite considerable efforts being made to investigate its efficacy in a number of large randomised clinical trials in different tumour types, results have been disappointing to date. This perspective article summarises how interest initially developed in the oncological potential of metformin and the diverse clinical programme of work to date including our contribution to establishing the intra-tumoral pharmacodynamic effects of metformin in the clinic. We also discuss the lessons that can be learnt from this experience and whether a further clinical investigation of metformin in cancer is warranted.

Automated summary

Over the past 15 years, there has been extensive interest in repurposing the diabetes drug metformin as a cancer treatment. However, despite numerous large clinical trials in various tumor types, the results have been disappointing. This article summarizes the initial interest in metformin's potential in oncology, the current clinical program, and the lessons learned from this experience regarding further investigation of metformin in cancer.