An Effect of Retatrutide on Cancer Progression in Mice?

Intriguing observations on the effect of retatrutide on cancer progression in mice appeared Friday in NPJ Metabolic Health and Disease. Retatrutide is the first triple agonist to progress in clinical development for obesity. Lilly said recently that they expect to release phase three clinical trial data for it later this year – earlier than previously expected. Earlier results with this drug have already sparked considerable excitement.

Pancreatic and Lung Cancer

In their research Sandesh Marathe and colleagues focused on two types of cancer – pancreatic ductal adenocarcinoma and lung adenocarcinoma. The reduced progression of pancreatic cancer yielded a striking 14-fold reduction in tumor volume. For comparison, the effect of semaglutide on tumor volume was a four-fold reduction.

In lung cancer the reduction of tumor volume was 17-fold.

The authors offer bold conclusions:

“In summary, findings presented herein have profound implications for patients currently considering or taking incretin mimetics for diabetes or weight loss on cancer outcomes.”

Building on Knowledge

These findings, though striking, are not simply a bolt from the blue. They build upon a base of knowledge about obesity, its relationship to cancer, and its treatment, especially with metabolic surgery. The authors explain:

“Incretin agonists are groundbreaking advances in medicine, enabling for the first time the study of non-surgical interventions for effective and sustained weight loss, which is presenting many exciting avenues for future investigation. Bariatric surgery-mediated weight loss is associated with both reduced cancer risk and mortality, with improved therapeutic effectiveness, although the mechanisms remain unclear. It is uncertain if patients taking various incretin agonists will be revealed to have the same impressive benefits.”

As our knowledge grows, we have more reasons to believe that better therapies for obesity can become an important strategy for preventing obesity-related cancers. Learning that retatrutide might prevent cancer progression is an important step along the way.

These are exciting times for progress in obesity care.

Click here for the study by Marathe et al and here for more on the relationship between obesity and cancer.

Three White Mice, painting by Ohara Koson / WikiArt

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March 19, 2025