Metformin, a widely prescribed drug for type 2 diabetes, has shown potential in combating lung cancer, particularly in overweight or obese individuals. Research from Roswell Park Comprehensive Cancer Center indicates that metformin's anticancer effects are primarily observed in the context of obesity, offering new avenues for treatment and prevention strategies.
Targeted Benefit in Overweight/Obese Patients
Previous clinical trials exploring metformin's role in lung cancer treatment yielded mixed results. However, a recent study published in the Journal of the National Cancer Institute focused on the body mass index (BMI) of patients, revealing that metformin's benefits are most pronounced in overweight or obese individuals. The study, led by Sai Yendamuri, MD, MBA, FACS, analyzed data from patients with non-small cell lung cancer (NSCLC) who underwent surgery or received immunotherapy.
Improved Outcomes and Immune Response
The research team reviewed data from overweight/obese and normal-weight patients who underwent surgery for NSCLC, as well as those who received immune checkpoint inhibitors. Key findings include:
- Overweight patients taking metformin and undergoing surgery experienced longer periods of recurrence-free survival.
- In preclinical lung cancer models, metformin slowed tumor growth and reversed obesity-caused suppression of the immune system.
- Combining metformin with an anti-PD1 antibody therapy (an immune checkpoint inhibitor) resulted in even better tumor control, but only in obese models.
Joseph Barbi, PhD, Assistant Professor of Oncology, noted that metformin appears to shift the balance between biological processes that suppress the immune system and those that actively kill tumors in obese or overweight patients. The hazard ratio (HR) for recurrence was 0.47, indicating nearly a 50% reduction in risk for those taking metformin.
Clinical Trial and Future Directions
Based on these findings, Drs. Yendamuri and Barbi have designed a phase 2 clinical trial to assess metformin's potential in preventing lung cancer in high-risk overweight or obese individuals. This trial, funded by the National Cancer Institute, is being conducted at Roswell Park and two other centers in the U.S. and Canada.
Affordability and Accessibility
Metformin's affordability and accessibility make it a promising candidate for repurposing in cancer treatment. A month's supply of metformin can cost as little as $10, making it a cost-effective option for patients. "Metformin has been used for 30 years and has a long record of safety," said Yendamuri. "If we can repurpose it to fight cancer, that’s very exciting."
