Novo Nordisk’s Weight Loss Drug Faces Setback as Lilly’s Zepbound Maintains Lead
Novo Nordisk’s next-generation weight-loss drug, CagriSema, has hit a roadblock in its development, failing to demonstrate superiority over Eli Lilly’s tirzepatide (Zepbound) in a recent head-to-head trial. The news sent Novo Nordisk’s stock plummeting, wiping out billions in market valuation and intensifying the competition in the rapidly evolving obesity drug market.
CagriSema Trial Results Disappoint
The Phase III REDEFINE 4 trial revealed that patients treated with a 2.4 mg dose of CagriSema achieved a weight loss of 23% after 84 weeks, compared to 25.5% weight loss observed in patients receiving a 15 mg dose of tirzepatide 1. Applying a treatment regimen estimand, which accounts for adherence and discontinuation, CagriSema resulted in 20.2% weight loss versus 23.6% with Zepbound 4. The trial’s primary endpoint, demonstrating non-inferiority in weight loss, was not met.
Market Reaction and Stock Performance
Following the announcement on Monday, Novo Nordisk’s stock price fell by over 16%, reaching its lowest level since June 2021 1. This decline represents a significant shift in the market, as Novo Nordisk previously held a dominant position in the injectable weight-loss drug sector.
Competition Heats Up in the Obesity Drug Market
The setback for Novo Nordisk comes as competition in the obesity drug market intensifies. Eli Lilly’s tirzepatide, marketed as Zepbound and Mounjaro, has gained traction, surpassing Novo Nordisk’s semaglutide (Ozempic and Wegovy) in U.S. Prescriptions 1. Lilly recently launched a new Zepbound formulation offering a month’s supply in a single pen 1.
Industry Experts Weigh In
Analysts have expressed concern over the trial results. Michael Shah, a Bloomberg Intelligence analyst, stated that the trial “backfired,” as the expectation was for CagriSema to perform in line with Zepbound 2. Though, other experts emphasize the need for a range of treatment options. Chris O’Donnell, founder of My Weight Loss Clinic, noted that different compounds may suit different individuals 2. Dr. Kieran Dang, chief medical officer at Mosh, highlighted the importance of combining medications with structured weight loss programs 2.
Novo Nordisk’s Future Plans
Despite the setback, Novo Nordisk remains committed to developing and launching CagriSema. The company plans to initiate a new Phase 3 trial with a higher dose of CagriSema in the second half of 2026 3. Novo Nordisk’s chief scientific officer, Martin Holst Lange, stated that further studies are needed to assess the drug’s “full weight-loss potential” 3. The company as well points to the cardiometabolic benefits and extensive safety data of semaglutide, with over 49 million patient years of exposure.
Financial Impact and Legal Challenges
Novo Nordisk has experienced a significant decline in market valuation, losing 60% of its value over the past year and wiping out $475 billion in shareholder wealth since its peak in 2024 2. The company is also facing legal challenges, recently suing obesity drug retailer Hims &. Hers for alleged patent infringement related to a “knock-off” version of Wegovy 2.