Repurposing of Metformin for Cancer Therapy: Updated Patent and Literature Review

Background: Over recent years, there has been an increasing focus on the repurposing of existing, well-known medications for new, novel usage. One such drug is metformin, typically utilized in the management of diabetes, which demonstrates a positive relationship between its administration and lower cancer morbidity and mortality. Based on this finding, numerous studies and clinical trials have been conducted to examine the potential usage of metformin as an anticancer agent. Objective: This article aims to summarize metformin’s anticancer effects through reviewing its literatures and patents, with a focus on its potential to be repurposed for cancer therapy. Methods: Various databases were examined using keywords, ‘Metformin’ and ‘Cancer’. Research articles were collected through the PubMed database, clinical trials were obtained from the Clinical Trials database, and patents were collected through the Google Patents database. Results: Metformin shows antineoplastic activity in various models. These anticancer properties appear to synergize with existing chemotherapeutics, which allows a reduction in drug dosage without losing potency while minimizing adverse effects. Numerous patents on metformin have been filed which claim various combination therapies, delivery methods, and uses for cancer therapy, displaying an increasing interest in metformin’s anticancer potential. Conclusion: Preclinical studies, along with early phase clinical trials, have examined the antitumor properties of metformin on a variety of cancers. Metformin’s anticancer effects are well documented, demonstrating a great promise in improving current cancer therapies. However, there is a significant lack of late phase clinical trials, specifically those involving nondiabetic cancer patients, and therefore further research in this area is required.