Reducing Cancer Risks
Sai Yendamuri, MD, chair of the Department of Thoracic Surgery and director of the Thoracic Surgery Laboratory at Roswell Park Comprehensive Cancer Center in Buffalo, New York, is leading a phase 2 trial exploring whether metformin can prevent lung cancer in people with overweight or obesity who are at a high risk for the malignancy.
The study, which has accrued about 60% of its estimated enrollment, also will assess whether metformin can reprogram participants’ immune systems, with a view toward reducing the activity of regulatory T cells that are linked to development of tumors.
“In our preclinical and retrospective clinical data, we found that metformin had anticancer effects but only if the patients were overweight,” Dr. Yendamuri said. “In mice, we find that obesity increases regulatory T-cell function, which suppresses the immune system of the lungs. This effect is reversed by metformin.” The team is conducting the current study to examine if this happens in patients, as well. Results are expected next year.
Research is underway in other tumor types, including oral and endometrial, and brain cancers.
Preventing Alzheimer’s Disease
Cognitive function — or at least delaying its erosion — represents another front for metformin. José A. Luchsinger, MD, MPH, vice-chair for clinical and epidemiological research and director of the section on geriatrics, gerontology, and aging at Columbia University Irving Medical Center in New York City, is heading a phase 2/3 randomized controlled trial assessing the ability of the drug to prevent Alzheimer›s disease.
The study investigators hope to enroll 326 men and women aged 55-90 years with early and late mild cognitive impairment, overweight or obesity, and no diabetes.
“The hypothesis is that improving insulin and glucose levels can lead to lowering the risk of Alzheimer’s disease,” Dr. Luchsinger said. Recruitment should be complete by the end of 2024 and results are expected in late 2026.
Similar studies are underway in Europe and Asia.
Other areas of investigation, while tantalizing, are mostly in early stages, although bolstered by preclinical and mechanistic studies. The authors of a recent review on the potential mechanisms of action of metformin and existing evidence of the drug›s effectiveness — or lack thereof — in treating diseases other than diabetes, wrote: “Collectively, these data raise the question: Is metformin a drug for all diseases? It remains unclear as to whether all of these putative beneficial effects are secondary to its actions as an antihyperglycemic and insulin-sensitizing drug, or result from other cellular actions, including inhibition of mTOR (mammalian target for rapamycin), or direct antiviral actions.”
Off-Label Uses
Metformin currently is approved by the US Food and Drug Administration only for the treatment of type 2 diabetes, although it is also the only antidiabetic medication for prediabetes currently recommended by the American Diabetes Association.
Some studies currently are looking at its use in a variety of off-label indications, including obesity, gestational diabetes, weight gain from antipsychotics, and polycystic ovary syndrome.
For the most part, metformin is considered a safe drug, but it is not risk-free, Dr. Jain cautioned.
“Although it would certainly be helpful to see if this inexpensive medication that’s universally available can help in disease states, one shouldn’t overlook the potential risk of adverse effects, such as gastrointestinal, potential vitamin B12 deficiency, blunting of skeletal muscle development and the rare risk of lactic acidosis in those with kidney impairment,” he said.
“Similarly, with recent reports of the carcinogenic potential of certain formulations of long-acting metformin that contained NDMA [N-nitrosodimethylamine], it would be imperative that these kinks are removed before we incorporate metformin as the gift that keeps giving.”
Dr. Jain reported financial relationships with Abbott, Amgen, Boehringer Ingelheim, Dexcom, Eli Lilly, Janssen, Medtronic, Merck, and Novo Nordisk. Dr. Yendamuri disclosed serving on the scientific advisory board member of Karkinos Healthcare and research funding from Lumeda for the metformin study. Dr. Luchsinger reported receiving donated metformin and matching placebo from EMD Serono, a subsidiary of Merck, for the MAP study. Dr. Schwartz received research support from the US Department of Veterans Affairs as National Chair of the VA-IMPACT trial.
A version of this article appeared on Medscape.com.