Novo Nordisk sues Eli Lilly over ads comparing Wegovy and Zepbound

Novo Nordisk has sued Eli Lilly in the U.S. District Court for the District of New Jersey, accusing the drugmaker of misleading consumers through nationwide advertising that portrays Lilly's obesity and diabetes drugs as more effective than Novo's rival treatments. Novo says the campaigns for Zepbound and Mounjaro rely on outdated clinical trial data by comparing Lilly's highest doses with lower doses of Novo drugs, while omitting newer evidence on higher FDA-approved doses of Wegovy and Ozempic. The dispute centers on ads comparing Zepbound with Wegovy and Mounjaro with Ozempic. Novo says Lilly's Zepbound campaign compares the maximum tolerated 10/15 mg doses of Zepbound with 1.7/2.4 mg Wegovy, but does not include the 7.2 mg injectable Wegovy dose approved by the FDA in March 2026, which showed average weight loss of about 19%, or roughly 47 pounds, in the STEP UP trial. Novo also says Lilly compares Mounjaro 15 mg with Ozempic 1 mg even though the FDA approved a 2 mg maintenance dose of Ozempic more than four years ago. The company argues there is no head-to-head clinical trial comparing the highest doses of Zepbound and Wegovy. Novo is bringing federal and state unfair competition and false advertising claims, including under the Lanham Act, and is asking the court to permanently halt the ads and require corrective advertising. It said it may seek a preliminary injunction in the coming days if Lilly does not remove the ads voluntarily. John F. Kuckelman, senior vice president and Group General Counsel, Novo Nordisk, said patients deserve current and accurate information as newer treatment options become available.