The FDA approves a new version of the diabetes drug Mounjaro for weight loss

A new version of the popular diabetes drug Mounjaro may be sold as a weight-loss drug, U.S. regulators announced Wednesday.

The US Food and Drug Administration has approved Eli Lilly’s drug called Zepbound. The drug, also known as tirzepatide, helped dieters lose up to 40 to 60 pounds in tests.

Zepbound is the latest diabetes drug approved for chronic weight management, joining Novo Nordisk’s Wegovy, a high-dose version of its diabetes drug Ozempic. Both are weekly injections.

The FDA approved Lilly’s drug for people who are considered obese and have a body mass index of 30 or higher, or for people who are overweight and have an associated health condition such as high blood pressure, high cholesterol or diabetes. The drug should be combined with a reduced-calorie diet and regular exercise, the FDA said.

In the United States, at least 100 million adults and about 15 million children are considered obese.

The drugs tirzepatide in Zepbound and Mounjaro and semaglutide in Wegovy and Ozempic work by mimicking hormones that act after eating to regulate appetite and satiety. Both mimic a hormone called glucagon-like peptide-1, known as GLP-1. Tirzepatide targets a second hormone called glucose-dependent insulinotropic polypeptide, or GIP.

The FDA approval was based on two large studies: More than 2,500 participants received varying strengths of Zepbound and nearly 1,000 people received dummy shots over a 16-month period. Participants without diabetes who received the highest dose lost about 18% of their weight, or about 41 pounds (19 kilograms), compared to placebo. Diabetics who find it more difficult to lose weight have lost about 12%, or nearly 27 pounds (12 kilograms), according to the FDA.

In another recent study, the drug helped people lose up to a quarter of their weight, or 60 pounds (27 kilograms), when combined with intensive diet and exercise.

Overall, Zepbound appears to produce more weight loss than Wegovy. Wegovy was approved for weight loss in 2021 and helped people lose about 15% of their weight, or 34 pounds (15 kilograms), according to study results.

“This would be the most effective drug ever approved to treat obesity,” said Dr. Fatima Cody Stanford, an expert in obesity medicine at Massachusetts General Hospital in Boston.

Semaglutide and tirzepatide drugs, touted by celebrities and on social media, were already in such demand that their manufacturers were struggling to keep up. Both have been listed on the FDA’s drug shortages page for months. All strengths of tirzepatide are currently listed as available, but a company spokesperson said this may vary based on location and demand.

Side effects of the new weight loss drug include vomiting, nausea, diarrhea, constipation and other gastrointestinal problems. In the most recently published study, about 10% of people who took tirzepatide dropped out of the study because of such problems, compared with about 2% of people who received dummy shots.

While experts praised Zepbound’s approval, they worried it wouldn’t necessarily mean greater access to the drug, which is prescribed “off-label” to help people lose weight.

“Most patients cannot afford Zepbound without insurance coverage, and many health insurance plans exclude obesity treatment,” said Dr. Katherine Saunders, an obesity expert at New York’s Weill Cornell Medicine and co-founder of a company focused on treating obesity.

Eli Lilly and Co. said the list price will be about $1,000 a month, the same as Mounjaro. The drug is expected to be available in the United States by the end of the year, the company said. The dosage strengths are the same for Zepbound and Mounjaro.

Kelly Burns, 50, of St. Petersburg, Florida, lost nearly 100 pounds using tirzepatide after participating in a 2021 study of the drug to treat obesity. When the testing ended and she no longer had access to the medication, she struggled but eventually lost another 50 pounds (23 kilograms).

“My whole life is completely different,” she said. Her health improved and her self-confidence increased. Now that Burns is approved for weight loss, she plans to check with her insurance company about coverage. “It would be ridiculous not to,” she said, adding, “I want to stay like this for as long as possible.”

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