Novo Nordisk sues Eli Lilly over alleged misleading weight-loss drug ads

Published Jul 21, 04:22 PM UTC

Novo Nordisk has filed a lawsuit against Eli Lilly in the US, accusing its rival of running a deceptive advertising campaign that misleads consumers about the comparative efficacy of their respective obesity and diabetes drugs. Novo claims Lilly's ads rely on outdated clinical studies to suggest that Lilly's tirzepatide (Mounjaro/Zepbound) outperforms Novo's semaglutide (Ozempic/Wegovy) in average weight loss. Specifically, Novo objects to Lilly omitting data on the highest 7.2mg dose of Wegovy, which showed 19% average weight loss, compared to Zepbound's 20.9% at its highest dose, noting no head-to-head trial has compared the highest doses. Novo seeks a permanent injunction to remove the ads and run corrective advertising. Lilly defends its ads as truthful and based on the SURMOUNT-5 study, which compared lower doses. The lawsuit comes amid heightened US scrutiny of direct-to-consumer drug advertising, following a 2025 presidential directive to crack down on misleading pharma ads.