LONDON (Reuters) – Shares in Novo Nordisk (NYSE:), maker of the wildly popular obesity drug Wegovy, fell 1.9% on Tuesday after the publication of a data analysis showing that Mounjaro, rival Eli’s own treatment Lilly (NYSE:), is leading the charge for faster and greater weight loss.
The analysis was published Monday in JAMA Internal Medicine, a medical journal. It examined health records and other data to assess the rate and percentage of weight loss in overweight and obese people who took tirzepatide – the active ingredient in Lilly’s Mounjaro and Zepbound – and semaglutide – the main ingredient in Wegovy and Ozempic.
In the absence of head-to-head randomized controlled trials comparing the two drugs, researchers used health records and pharmacy dispensing data to analyze weight loss trajectories in 9,193 patients who received Mounjaro and the same number of closely matched patients who received Ozempic. The average participant weighed 242 pounds (110 kg) and about half had type 2 diabetes.
After taking into account individual risk factors, patients taking Mounjaro were 76% more likely to lose at least 5% of their body weight, more than twice as likely to lose at least 10%, and more than three times as likely to lose at least 15 % of their body weight to lose. %, compared to patients taking Ozempic, the report shows.
Novo Nordisk said in an emailed statement: “This analysis compared weight loss outcomes of semaglutide (Ozempic) and tirzepatide (Mounjaro) and did not include Wegovy, even though weight loss was the main goal assessed.” It said the best way to compare the two weight-loss drugs is through a head-to-head clinical trial, noting that such a trial has not yet been completed.
A Lilly spokesperson declined to comment, saying the company was not involved in the investigation. The spokesperson said the company is currently studying tirzepatide and semaglutide in obese patients in a late-stage trial expected to be completed later this year.
The two drugmakers, the world’s largest makers of insulin, are the first to bring highly effective weight-loss drugs to market, a booming market that some analysts say could be worth $150 billion in annual sales by the early 2030s. Both are rushing to increase production of their drugs, which come in a self-injection pen administered once a week.
The researchers noted that Ozempic and Mounjaro are both intended for use by people with type 2 diabetes, but half of the study participants used the drugs only for weight loss, which may have affected the results.
The results of this analysis were initially published on the medRxiv website in November, prior to peer review.
Shares in Novo and Lilly are at record highs thanks to profits from the weight-loss drugs. While Novo’s Wegovy has been on the market in the United States since 2021, Lilly’s version, sold in the US as Zepbound, only launched there late last year.
