Approval for Eli Lilly obesity drug sets up rival to Wegovy

Regulators on both sides of the Atlantic have cleared Eli Lilly’s injectable diabetes medication for use as a weight loss treatment, creating the first direct rival to Wegovy, Novo Nordisk’s obesity drug.

The US Food and Drug Administration and the UK’s Medicines and Healthcare products Regulatory Agency said patients in clinical trials of Lilly’s tirzepatide had seen “significant” weight loss compared with those given a placebo. At the highest dose, patients had lost nearly 50lbs on average, Lilly said.

The regulators cleared the drug for weight-loss use for obese and overweight adults in conjunction with a lower-calorie diet and increased exercise. Tirzepatide is already sold under the name Mounjaro as a diabetes treatment in both countries. It will keep that brand name in the UK as an obesity treatment but will be sold in the US as Zepbound for weight loss.

About 70 per cent of adults in the US and 64 per cent in the UK are obese or overweight, according to the FDA and the House of Commons library. It contributes to some of the most common causes of death, such as heart disease, stroke and diabetes.

“Today’s approval addresses an unmet medical need,” said John Sharretts, director of the diabetes and obesity division in the FDA’s Center for Drug Evaluation and Research in a statement. 

Steve Barclay, the UK health and social care secretary, hailed Mounjaro’s potential to help cut waiting lists and save the National Health Service “billions of pounds”.

Tirzepatide will compete head on with Novo Nordisk’s Wegovy, which has come to dominate the market for so-called GLP-1 weight-loss and diabetes management drugs with a 54.3 per cent global market share. 

Tirzepatide is the first approved treatment that uses two agents, called dual agonists, including both GLP-1 and GIP. That made it more potent than Wegovy, said Fatima Cody Stanford, an obesity medicine physician and associate professor at Harvard Medical School and Massachusetts General Hospital. 

“This new agent is the most efficacious of the [weight-loss drugs] we have seen so far,” she said.

Beverly Tchang, an obesity medicine physician at Weill Cornell Medicine and diplomate of the American Board of Obesity Medicine, said the medical community was “extremely excited to have the official FDA approval of tirzepatide for the treatment of obesity”.  

“The only people more excited than us are my patients,” she said.

The side effects of Eli Lilly’s and Novo Nordisk’s obesity treatments are very similar, and patients could switch from one to the other, Stanford said. Studies show that, as with Wegovy, patients who stop taking tirzepatide see a quick rebound in weight. 

Lilly expects to sell the new jab at a list price of nearly $1,060, but said this would be 20 per cent lower than Wegovy. David Risinger, a Leerink analyst, said in a note on Wednesday that the company had designed its pricing to encourage coverage in employers’ health insurance plans.

Novo Nordisk has struggled to meet the demand for Wegovy, leaving many patients facing supply issues that have interrupted their treatment for a month at a time in some cases, said Tchang. Interruptions led to weight gain and psychological challenges for patients who were meant to take the drug continuously, she said.