Ozempic maker Novo Nordisk sues US rival over ‘materially misleading’ ads

Novo Nordisk has filed a lawsuit against its US rival Eli Lilly, accusing the American drugmaker of running “false and materially misleading” advertisements for its weight-loss and diabetes treatments, according to a monitored public feed citing The Guardian Business.

The Danish pharmaceutical company, best known for Ozempic, said the disputed marketing gives consumers a distorted view of how the companies’ medicines compare. Novo Nordisk alleges that Lilly relied on outdated trial data and chose studies that made its products appear more effective than Novo Nordisk’s in head-to-head promotions.

The complaint centers on Lilly’s competing weight-loss and anti-diabetes drugs, including Zepbound and Mounjaro. Novo Nordisk said the advertising campaign used “intentionally selected outdated studies” and compared Lilly’s highest doses with lower doses of Novo Nordisk medicines, a comparison the company argues is misleading.

The legal move adds to the growing commercial rivalry between two of the biggest names in the global obesity-drug market. Both companies have been racing to expand their share of a fast-growing category that has transformed the pharmaceutical industry and drawn intense investor attention.

Novo Nordisk’s challenge is aimed at advertising claims rather than the underlying medicines themselves, at least based on the details currently available in the feed. The company’s filing underscores how aggressively drugmakers are competing to position their treatments as the strongest option in an increasingly crowded market for weight-loss and diabetes care.

The dispute also highlights how promotional language and clinical comparisons can become central battlegrounds when blockbuster medicines are involved. In a market where patient demand, prescribing patterns and insurer coverage can all be influenced by public messaging, claims of misleading advertising can carry significant commercial weight.

For now, the available details are limited to Novo Nordisk’s accusation that Lilly’s ads rely on outdated evidence and unfair dose comparisons. No response from Eli Lilly was included in the feed summary.

This report is based on a monitored public feed and sourced from The Guardian Business. Source: The Guardian Business - https://www.theguardian.com/business/2026/jul/21/novo-nordisk-eli-lilly-weight-loss-ads