Novo Nordisk shares plunged more than 15% Monday after the Danish pharmaceutical company announced its experimental obesity drug, CagriSema, failed to demonstrate superior weight loss compared to Eli Lilly’s Zepbound in a head-to-head phase 3 trial.
The REDEFINE 4 trial, involving 809 participants with obesity and comorbidities, showed that patients treated with CagriSema 2.4 mg/2.4 mg achieved a weight loss of 23.0% after 84 weeks, compared to 25.5% with tirzepatide 15 mg – the active ingredient in Zepbound. Applying a treatment-regimen estimand, CagriSema resulted in 20.2% weight loss versus 23.6% for tirzepatide.
“The trial did not achieve its primary endpoint of demonstrating non-inferiority on weight loss for CagriSema compared to tirzepatide after 84 weeks,” Novo Nordisk stated in a press release. The trial was designed to assess a fixed-dose combination of cagrilintide and semaglutide.
The disappointing results arrive as Novo Nordisk faces increasing competition from Eli Lilly in the lucrative weight-loss market. Zepbound has already surpassed Novo Nordisk’s Wegovy and Ozempic in U.S. Prescriptions, according to reports. Eli Lilly too launched a new, higher-dose formulation of Zepbound on Monday, offering a month’s supply in a single pen.
Despite the setback, Novo Nordisk indicated it will continue to explore the potential of CagriSema through additional trials, including higher-dose combinations. A phase 3 trial evaluating a higher dose of CagriSema (2.4 mg/7.2 mg) is planned to initiate in the second half of 2026, focusing on adults with obesity.
The news of the trial failure sent Novo Nordisk’s Copenhagen-listed shares to their lowest level since June 2021, falling 16% to 251 Danish kroner. Eli Lilly’s stock experienced a more moderate decline, dropping 4.7%.
Novo Nordisk’s struggles with CagriSema add to a series of recent challenges for the company, including rising competition, price reductions in the U.S., and the impending loss of exclusivity for Wegovy and Ozempic in certain markets.
