Eli Lilly's tirzepatide shows superior weight loss to Novo's semaglutide

Phase 3b trial finds Lilly's tirzepatide delivers higher average weight loss and waist reduction than Novo's semaglutide in people with obesity or overweight

US-based pharmaceutical company Eli Lilly has announced results from a head-to-head clinical trial showing that its obesity drug tirzepatide (sold as Mounjaro) led to greater weight loss in adults than semaglutide (sold as Wegovy).

 

The detailed findings from the 72-week phase 3b SURMOUNT-5 trial were presented at the European Congress on Obesity and published in The New England Journal of Medicine.

 

Participants using tirzepatide lost an average of 20.2 per cent of their body weight, or 22.8 kg, compared to 13.7 per cent, or 15.0 kg, with semaglutide. The trial included 751 adults with obesity or overweight with weight-related health conditions, but without diabetes.

 

Tirzepatide also performed better on all secondary goals. Nearly 65 per cent of participants taking tirzepatide lost at least 15 per cent of their body weight, compared to 40 per cent on semaglutide. In terms of waist circumference, the average reduction was 18.4 cm with tirzepatide and 13.0 cm with semaglutide.

 

The trial was not designed to directly compare the safety profiles of the two drugs. However, gastrointestinal issues were the most common side effects in both groups. About 6.1 per cent of participants on tirzepatide stopped treatment due to side effects, compared to 8.0 per cent on semaglutide.

 

In India, Eli Lilly markets tirzepatide as Mounjaro for type 2 diabetes, and is positioning it for use in obesity care as well. “The results from SURMOUNT-5 provide evidence for tirzepatide as a treatment option for obesity in India,” said Winselow Tucker, President and GM, Eli Lilly India.

 

Both medications are part of a newer class of drugs that act on hormone receptors involved in appetite regulation. Tirzepatide targets two receptors (GIP and GLP-1), while semaglutide targets only one (GLP-1). Participants in the study were also advised on a reduced-calorie diet and physical activity.

 

Eli Lilly’s tirzepatide is sold as Zepbound in the US for obesity, and as Mounjaro for type 2 diabetes. Semaglutide is marketed by Novo Nordisk under Wegovy for obesity and Ozempic for type 2 diabetes.

 

Ongoing studies are assessing tirzepatide’s effect on conditions such as kidney disease and sleep apnoea in patients with obesity.