The Food and Drug Administration on Wednesday approved a powerful new medicine for weight loss, clearing Eli Lilly’s Zepbound for adults with obesity or who are overweight and have at least one related health condition.
The drug, which was already available to treat Type 2 diabetes under the brand name Mounjaro, is one of a class of medicines known as GLP-1 agonists that have revolutionized the treatment of obesity. Demand for these drugs is already sky-high and outstripping the ability of their makers, most prominently Lilly and rival Novo Nordisk, to supply them.
“Obesity and overweight are serious conditions that can be associated with some of the leading causes of death such as heart disease, stroke and diabetes,” said John Sharretts, head of the FDA’s division for diabetes, lipid disorders and obesity, in a statement from the agency. “In light of increasing rates of both obesity and overweight in the United States, today’s approval addresses an unmet medical need.”
According to statistics from the National Institutes of Health, nearly 1 in 3 adults in the U.S. are overweight, while more than 40% have obesity. Excessive weight is associated with a range of other health conditions, including diabetes and heart disease.
GLP-1 agonists activate a receptor for a gut hormone of the same name, and are thought to work by reducing appetite and slowing gastric emptying.
While early versions of GLP-1 agonists had only modest effects, newer drugs like Wegovy, Mounjaro and Novo’s Ozempic offer better blood sugar control and more substantial weight loss. Their success has helped make GLP-1 therapies a dominant treatment type for metabolic disease, one that could possibly surpass insulin in global sales by the end of the decade.
Tirzepatide, the drug ingredient in Mounjaro and Zepbound, also stimulates another receptor known as GIP.
GLP-1 agonists’ benefit might not end with blood sugar and weight. Novo has reported trial results showing Wegovy can prevent heart related complications, which could help persuade insurers reluctant to cover the drug’s cost. The company has also recently released data showing Ozempic, which contains the same ingredient at a different dose, can help treat kidney disease.
The cardiovascular data for Wegovy is set to be presented at the American Heart Association’s annual meeting this weekend.
While Zepbound and Wegovy haven’t been tested head-to-head, Lilly’s data suggest its drug might lead to greater weight-loss. In clinical trials, Wegovy-treated participants lost between 10% and 16% of their body weight.
Lilly ran two large clinical trials testing Zepbound in overweight and obese people who either had or didn’t have diabetes. Results showed patients treated with the highest approved drug dose lost about 12% to 18% of their body weight.
In approving Zepbound, the FDA put a safety warning for severe gastrointestinal disease on the drug’s labeling — a caution that Wegovy did not receive. Both drugs carry black box warnings for the risk of thyroid tumors due to preclinical findings in rats, although it’s not clear if that risk is also present for humans.
Wegovy sales have risen fivefold this year, reaching 21.7 billion Danish krone, or about $3.1 billion over the first nine months of the year. Sales for Ozempic, a Novo GLP-1 drug approved for Type 2 diabetes treatment but used off-label in weight loss, were up 58% to over $9 billion.
Lilly, meanwhile, said Mounjaro sales were $3 billion during the first nine months of the year. The drug’s financial success to date, and prospect for greater revenue in the future, has helped make Lilly the most valuable pharmaceutical company, lifting its market value to nearly $600 billion.
Lilly said it will sell Zepbound for $1,059 per month at list price, about 20% less than what Novo charges for its rival drug Wegovy. The prices don’t account for rebates and discounts the companies offer to insurers, which can result in a much cheaper net price.
So far, Wegovy supply has been limited by manufacturing constraints, and remains restricted at the starter doses in order to ensure treatment for people already established on treatment.
Lilly has sought to prepare for high Zepbound demand. “We’re not at all happy with the capacity we’ve announced already. This is really all hands on deck,” CEO David Ricks told analysts last week.
Eli Lilly has asked for approval of Zepbound in Europe, China, the U.K. and in several other countries
Editor’s note: This story has been updated with additional detail throughout.