Tirzepatide, developed by Eli Lilly, is the active ingredient in Mounjaro and Zepbound, which have overtaken Novo Nordisk’s Ozempic and Wegovy in US prescriptions|@novonordisk; @EliLillyandCo|X

Novo Nordisk shares tumbled more than 15% Monday after the company said its next-generation weight-loss drug failed to match Eli Lilly in a late-stage trial.

The stock closed down about 16% at 251 Danish kroner in Copenhagen, its lowest level since June 2021. The decline extends a painful year, with shares down nearly 50% in 2025 as competition and pricing pressure weigh on growth.

Study results disappoint 
Novo said its experimental drug CagriSema did not meet its main goal of proving it was not inferior to tirzepatide.

CagriSema led to 20.2% weight loss over 84 weeks, compared with 23.6% for tirzepatide, which is developed by Eli Lilly and is the active ingredient in Mounjaro and Zepbound.

In recent months, Novo has lost market share in GLP-1 to Lilly.

Novo needed CagriSema to succeed as its GLP-1 patents are nearing expiry. Lilly’s patents still have time.

The Danish pharmaceutical’s setback follows a failed semaglutide Alzheimer’s trial, a leadership shakeup, and a scrapped biotech deal.

Adding to the pressure, Lilly shares rose after it introduced a new form of its Zepbound injector that provides four weeks of doses in a single device. Novo has shed about $475 billion in value since 2024, when it topped $650 billion.

What comes next?
Novo has already filed CagriSema for US approval, with a decision expected in late 2026. 

Analysts estimate the drug could contribute up to 25% of revenue by 2030. The company plans additional higher-dose trials as it fights to regain momentum.