Eli Lilly’s Zepbound takes on Novo Nordisk’s Wegovy in obesity drug showdown

In the fierce race to dominate the weight loss drug market, global pharmaceutical giant Eli Lilly announced on Wednesday that its weight loss treatment, Zepbound (tirzepatide), outperformed Novo Nordisk’s Wegovy (semaglutide) in a recent clinical trial.

The trial, known as SURMOUNT-5, found that participants using Zepbound lost an average of 20.2% of their body weight, while those on Wegovy lost 13.7%. This marks a 47% difference in weight loss between the two drugs.

The study included 751 adults with obesity or overweight who also had at least one associated health condition, such as high blood pressure or sleep apnea. Those using Zepbound lost an average of 50.3 pounds (22.8 kg), whereas those on Wegovy lost 33.1 pounds (15.0 kg). Additionally, 31.6% of people using Zepbound lost at least 25% of their body weight, compared to 16.1% of those on Wegovy.

Both Zepbound and Wegovy are GLP-1 receptor agonists, but they differ in their mechanisms. GLP-1 (glucagon-like peptide-1) is a hormone that helps regulate blood sugar levels, appetite, and digestion by stimulating insulin release and reducing hunger. Wegovy works by targeting the GLP-1 receptor to regulate appetite and aid in weight loss. Zepbound, however, is a dual-action drug that targets both the GLP-1 receptor and the GIP (gastric inhibitory polypeptide) receptor. This difference in approach could be one factor contributing to the larger weight loss seen in the Zepbound group, doctors have said.

Both drugs are part of the expanding market for obesity treatments, which is expected to continue growing as more people seek ways to manage their weight. According to projections, the global market for obesity drugs could be worth nearly $14 billion by 2032.

Zepbound has already been approved for use in people with type 2 diabetes under the brand name Mounjaro. The drug is also being investigated for other potential uses, including for heart disease and sleep apnoea, which may expand its range of applications.

While Wegovy has been a leading treatment in the weight loss sector, Zepbound’s results in the trial suggest it could emerge as a strong contender. Lilly plans to present more detailed findings from the SURMOUNT-5 trial at upcoming medical conferences.

The competition between Eli Lilly and Novo Nordisk, makers of Zepbound and Wegovy, reflects the growing interest in the weight loss drug market.

Currently, Novo Nordisk leads with Wegovy, a semaglutide-based drug that generated $5.5 billion in revenue in 2023. This success has cemented Wegovy as one of the leading treatments for obesity. However, Zepbound’s latest clinical trial results suggest it may be able to challenge Wegovy’s position in the market.

The weight loss drug market has become an important area of growth for both companies. Novo Nordisk’s success with Wegovy has contributed to its significant revenue growth, with a large portion of its 2023 revenue of $28 billion coming from Wegovy and other GLP-1 treatments. However, Eli Lilly’s approach with Zepbound, targeting two hunger-regulating pathways, could offer a more advanced solution to weight loss than Wegovy, which focuses on just one.

Both companies are also expanding their drug portfolios. Zepbound, which is already approved for treating type 2 diabetes under the name Mounjaro, is also being tested for cardiovascular disease, chronic kidney disease, and sleep apnea. Wegovy, meanwhile, is being explored for potential benefits in cardiovascular health and other obesity-related complications.

According to GlobalData, a data analysis firm, sales of GLP-1 receptor agonists are projected to reach $125 billion by 2033, with 90% of this revenue coming from obesity treatments. In India, Zepbound and Wegovy are not yet approved for weight loss, although semaglutide is available for managing type 2 diabetes under the brand name Ozempic.

Zepbound, approved for diabetes under the name Mounjaro, is also being considered for obesity treatment. India is experiencing a rising obesity burden, with around 5% of adults classified as obese and over 20% overweight, driven by urbanisation, sedentary lifestyles, and poor dietary habits. This growing health concern is increasing the demand for effective weight loss solutions, including medications like GLP-1 agonists.