Lilly gets FDA okay for tirzepatide as obesity therapy

Novo Nordisk is finally facing some major competition to its obesity franchise juggernaut, now that Eli Lilly’s rival therapy tirzepatide has been approved by the FDA as a weight-loss drug.

Already a blockbuster as a therapy for type 2 diabetes under the Mounjaro brand name, dual GLP-1/GIP agonist tirzepatide has been cleared for obesity as Zepbound, paving the way for a big increase in sales and setting up a battle for market share with Novo Nordisk’s GLP-1 agonist Wegovy (semaglutide).

The FDA has approved Zepbound for chronic weight management in adults who are obese with a body mass index of 30 or more, or overweight with a BMI of at least 27 and at least one weight-related health condition, such as high blood pressure, high cholesterol, and/or diabetes.

That is the same indication as Wegovy when it was first approved by the FDA for obesity in 2021, although, Novo Nordisk’s drug has since had its label extended to include obese adolescents aged 12 and over. Both drugs are given as subcutaneous injections once weekly.

Lilly said Zepbound should be launched before the end of the year, with a wholesale price of $1,060 for a month’s supply, a discount on Wegovy’s price of around 1,350 ahead of discounts.

It expects patients with insurance and obesity drug coverage to pay as little as $25 out-of-pocket for a one- or three-month prescription and said people whose insurance does not cover this category will be eligible for a 50% discount on the list price at $550 per month.

“Far too many hurdles continue to prevent people living with obesity from accessing obesity treatments that could lead to significant weight loss,” said Mike Mason, head of diabetes and obesity at Lilly.

“Broader access to these medicines is critical, which is why Lilly is committed to working with healthcare, government, and industry partners to ensure people who may benefit from Zepbound can access it,” he added.

There has already been considerable off-label prescribing of Mounjaro for weight loss, as well as Novo Nordisk’s Ozempic, the formulation of semaglutide indicated for diabetes, and all three drugs have been affected by supply constraints.

In its third-quarter update earlier this month, Lilly said supplies of tirzepatide would remain “tight” for the foreseeable future, but was working to double capacity by the end of the year.

Despite those constraints, Zepbound is expected to make rapid inroads into the market for obesity drugs, not least because it generated very impressive weight-loss results in clinical trials, achieving an average weight loss of around 16% to 22.5% of total body weight, while in Novo Nordisk’s pivotal trials the average reduction was in the range of 10% to 16%.

That comparison comes, however, with the usual caveat that trying to compare the outcomes of trials with different protocols is fraught with difficulty.

On the other hand, in Novo Nordisk’s favour is that it already has clinical data showing that the weight loss achieved with Wegovy translates to a reduced risk of cardiovascular disease, while Lilly isn’t expecting results from a similar outcomes study until 2027.

Losing 5% to 10% of body weight through diet and exercise has been associated with a reduced risk of cardiovascular disease in adults who are obese or overweight, but some insurance companies have baulked at providing coverage for the drugs, saying the cost is too great unless there is clear evidence of health benefits beyond weight loss.

Lilly is also running a head-to-head study that will pit the two rival drugs directly against each other, hoping to mirror another study in diabetes that showed Mounjaro was more effective than Ozempic in diabetes.

In a statement, the director of the FDA’s division of diabetes, lipid disorders and obesity – John Sharretts – said that tirzepatide’s approval addresses an “unmet medical need”, given the increasing rates of obesity and the overweight in the US.

Approximately 70% of American adults are obese or overweight, and many of those also have a weight-related condition. Analysts have suggested that the market for weight-loss drugs, driven by GLP-1 therapies, could reach $100 billion a year by 2030.