The maker of Ozempic and Wegovy has dragged its arch-rival to court, accusing the US pharmaceutical giant of running adverts that “deceptively” suggest its weight-loss drugs are superior.
Novo Nordisk filed a lawsuit in the US on Tuesday alleging that Eli Lilly’s campaigns for Mounjaro and Zepbound compared the highest approved doses of its medicines with lower doses of Novo Nordisk’s Ozempic and Wegovy, while omitting newer, higher-dose options. The Danish company said the ads “intentionally selected outdated studies” and “buried or omitted critical clinical context” to create a “misleading impression” of product-level superiority.
“Novo Nordisk sues Eli Lilly over ads it says falsely claim Lilly's weight-loss drugs are superior”
Eli Lilly hit back, insisting its advertising was “truthful, transparent and grounded in the most direct scientific evidence available”. A spokesperson pointed to the Surmount-5 trial – the only direct head-to-head randomised clinical trial comparing tirzepatide (Eli Lilly’s molecule) with semaglutide (Novo Nordisk’s) in weight management – and accused Novo of trying to prevent the company from communicating its results. “Rather than competing on the merits of its products, Novo is asking a court to prevent Lilly from communicating the results of this trial,” the spokesperson said, adding that Eli Lilly would defend the lawsuit “vigorously”.
The legal battle comes as the two pharmaceutical heavyweights fight for dominance in a weight-loss drug market that analysts estimate could be worth more than $100bn by 2030. Novo Nordisk’s general counsel, John F. Kuckelman, argued that “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”.
According to the lawsuit, Eli Lilly’s adverts were “aired during recent, widely viewed global sporting broadcasts and on TikTok and Facebook, causing widespread confusion”. Novo Nordisk is seeking a court order requiring Eli Lilly to pull the adverts and instead run a “corrective advertising campaign”. If the US company does not voluntarily remove the commercials, Novo said it would file a motion in the coming days for a preliminary injunction to block them.
Anti-obesity treatments like these mimic the hormone GLP-1, which is secreted by the intestines, and can be used for weight loss or to treat type 2 diabetes. As the market booms, the question now is whether a courtroom will determine not just the fate of these adverts, but the message patients receive about which drug works best.