GLP-1 Side Effects May Increase Kidney Cancer Risks: Study

The large number of users of Ozempic, Mounjaro and similar drugs means that even a slight increase in cancer risk could have significant health impacts, researchers warn.

A new study warns that while Ozempic, Mounjaro and similar diabetes and weight loss drugs may decrease the risk of most cancers, they may actually increase the odds of developing kidney cancer by more than a third.

Researchers published a review of cancer risks linked to Glucagon-like peptide-1 (GLP-1) receptor agonists in JAMA Oncology on August 21, finding that the drugs may reduce some cancer risks while increasing the risk of kidney cancer, and calling for more studies to understand the underlying mechanisms.

The most widely used and popular GLP-1 medication is Novo Nordisk’s Ozempic (semaglutide), which was originally approved in 2017 to treat type 2 diabetes. The discovery of its weight loss benefits later led to the development of Wegovy, which was approved specifically for treating obesity. Eli Lilly’s competing drug, Mounjaro (tirzepatide), is also approved for diabetes treatment, with a weight loss counterpart marketed as Zepbound. Other drugs in the GLP-1 class include Saxenda, Byetta, Victoza, Trulicity, Rybelsus and others.

Despite the spike in popularity of the drugs over the last several years, research has linked the drugs to a wide array of health risks, such as gastroparesis, or stomach paralysis, intestinal blockages, and even vision loss.

These findings have led to a growing number of Ozempic lawsuits, Mounjaro lawsuits, Wegovy lawsuits and other GLP-1 claims being filed over the past few years, each indicating that in the drug makers rush to promote the benefits associated with the treatments, they failed to adequately disclose potentially serious side effects some users experience.

GLP-1 Kidney Cancer Risks

In this latest study, researchers from the Regenstrief Institute in Indianapolis and the University of Florida conducted a retrospective study looking at clinical trials from 2014 to 2024 involving a total of 86,632 matched adults.

Led by Dr. Hao Dai, the team looked for evidence of 14 different types of cancer, 13 of those linked with obesity.

According to the data, the overall cancer incidence rate was 13.6 per 1,000 person years, compared to 16.4 per 1000 person-years for people who did not take the drugs. However, the researchers did find a 38% increased risk of kidney cancer, which they deemed as “marginally nonsignificant,” meaning it was just on the edge of registering as an increased risk. However, given the larger number of users taking the medications, it could have widespread impact.

“(T)aking GLP-1RAs may be associated with an increased risk of kidney cancer, highlighting the need for longer-term follow-up to clarify the underlying mechanisms and clinical implications of these findings.”

– GLP-1 Receptor Agonists and Cancer Risk in Adults With Obesity, JAMA Oncology

Despite the risks being slight, researchers noted that there were more than 137 million individuals currently eligible to take GLP-1 medications in the U.S., and that “even modest changes in cancer risk could have substantial public health implications.”

Ozempic, Mounjaro Gastroparesis Lawsuits

Individuals nationwide are pursuing more than 2,400 product liability lawsuits brought throughout the federal court system over the past two years, each indicating that Novo Nordisk and Eli Lilly, the manufacturers of Ozempic and Mounjaro respectively, failed to provide adequate warning that the diabetes and weight loss drugs could cause severe gastrointestinal problems.

Given common questions of fact and law raised throughout the complaints, all GLP-1  gastroparesis lawsuits have been centralized in a multidistrict litigation (MDL) in the Eastern District of Pennsylvania, where U.S. District Judge Karen Marston is overseeing coordinated discovery and pretrial proceedings. As part of that process, the court will eventually select a small group of representative cases to serve as early “bellwethers,” providing insight into how juries may respond to recurring evidence and testimony.

Before moving to that stage, Judge Marston directed both sides to resolve several issues with broad implications for the litigation, including those of preemption and general causation. Once those matters are addressed, the MDL is expected to proceed with preparing the first set of cases for jury consideration. While the verdicts will not directly determine the outcome of other GLP-1 claims, they are likely to shape settlement negotiations.

If the parties do not reach a GLP-1 settlement agreement after the bellwether trials, Judge Marston is likely to begin remanding the cases back to their original courts for individual trial dates.