The news: Novo Nordisk’s next-generation obesity drug CagriSema underperformed Eli Lilly’s Zepbound in a head-to-head trial, raising new questions about Novo’s ability to regain competitive ground in the weight loss market.

• Patients on CagriSema lost 23% of their body weight after 84 weeks, compared with 25.5% for Zepbound users.
• While the efficacy gap appears modest by exact numbers, analysts expected CagriSema to be at least as effective as Zepbound.
• The disparity in trial results caused Novo’s stock to drop by 15%, its lowest since 2021 before it launched Wegovy.

Why it matters: It’s the latest loss for Novo in a series of disappointments over the past few months, leaving Novo firmly in the runner-up spot behind Lilly for weight loss drugs.

• Earlier this month, Novo reported disappointing Q4 and full-year sales and said it expects sales to drop anywhere from 5% to 13% (hitting $40.5 billion to $44.3 billion) for this year.
• Meanwhile, Lilly topped investor expectations’ sales for 2025 and increased its revenue guidance to $80 billion to $83 billion for this year, topping analyst expectations of $78 billion.
• Novo is also facing generic competition for Wegovy (semaglutide) in several countries this year, including India, Canada, China, and Brazil, while Lilly’s Zepbound (tirzepatide) patent protection is expected through 2036.
• Novo was first to market with an oral weight loss option, Wegovy pill, and a surge of first-month sales. However, Lilly’s own pill option (orfoglipron) is expected to launch by midyear.

Implications for pharma companies: Novo’s latest setback shows how quickly command of the weight loss drug market can shift. As more drugmakers move into the space, matching Novo and Lilly’s benchmarks for efficacy and pricing is now table stakes. Pfizer, Amgen, Roche, and AstraZeneca all have ongoing trials with plans to enter the weight loss market, for instance. Pharma companies will need clear differentiation, such as easier dosing, fewer side effects, or stronger payer incentives, to stand out and maintain investor confidence.