Novo Nordisk sues Eli Lilly over misleading weight-loss drug ads
Denmark's Novo Nordisk has filed a lawsuit against US competitor Eli Lilly, alleging deceptive advertising that threatens to distort the fiercely competitive and highly lucrative market for GLP-1 weight-loss drugs.
Novo Nordisk is taking legal action against Eli Lilly, accusing the American drugmaker of running "false and materially misleading" advertisements for its weight-loss and anti-diabetes treatments, Zepbound and Mounjaro.
The Danish pharmaceutical giant claims its rival intentionally cherry-picked outdated clinical studies. According to Novo Nordisk, Lilly compared the highest doses of its own drug, tirzepatide, against lower doses of Novo's semaglutide. The company alleges the campaign presented these results as proof of overall superiority while hiding critical clinical context.
These claims were broadcast during major global sporting events and pushed across TikTok and Facebook. For European investors, the dispute highlights the escalating commercial battle over a class of drugs that has become an unprecedented financial windfall for both companies.
Anti-obesity treatments that mimic the GLP-1 hormone have transformed the market for type 2 diabetes care and weight management. The competing molecules developed by Novo Nordisk and Eli Lilly are now central to the financial performance of both businesses.
John F Kuckelman, Novo Nordisk’s general counsel, warned that consumers are being denied accurate information. “As new and more effective treatment options become available, people deserve accurate information that reflects the latest scientific evidence and helps them make informed care decisions,” he said.
Kuckelman added that superficial fixes are unacceptable in major national campaigns. “Healthcare companies have a responsibility to keep their public claims accurate and current – ineffective, fine-print disclaimers do not fix the misleading impression created by major national campaigns.”
Eli Lilly has firmly rejected the allegations. The company defended its campaign by pointing to the Surmount-5 trial, which it says is “the only direct, head-to-head randomised clinical trial comparing tirzepatide and semaglutide in the context of weight management.”
A spokesperson for the US group accused Novo Nordisk of trying to suppress legitimate scientific data. “Rather than competing on the merits of its products, Novo is asking a court to prevent Lilly from communicating the results of this trial. We firmly stand by our advertising campaign.”
