Novo Nordisk sues rival Eli Lilly over weight loss drug advertising

Drugmaker Novo Nordisk sued rival Eli Lilly on Tuesday, accusing the company of false advertising over the performance of its weight loss drugs. 

The lawsuit, filed in federal district court in New Jersey, alleges Lilly intentionally selected outdated studies to show the use of Mounjaro and Zepbound lead to significantly more weight loss than Novo Nordisk’s Ozempic and Wegovy. 

The studies compared higher doses of Lilly’s medicine against lower doses of Novo’s drugs, the complaint alleged, while omitting newer, higher-dose versions that Novo said deliver greater weight loss. 

“Lilly clearly knows that the Food and Drug Administration has approved newer, more effective doses of Novo Nordisk’s medicines that offer patients additional weight reduction or glycemic control. But Lilly omits that information,” the lawsuit stated. 

There are no head-to-head clinical trials comparing the highest doses of the respective medicines, but more recent data shows that Novo’s drugs can help patients lose a comparable amount of weight as Lilly’s, Novo Nordisk said. 

Although Eli Lilly acknowledges the existence of a higher dose of Wegovy in a small footnote at the bottom of its advertising screen, “that footnote is ambiguous, confusing, virtually illegible, and wholly inadequate,” the complaint alleged.

The advertising campaigns have aired nationally across major broadcast and cable networks and through sponsored social media advertising on TikTok and Facebook, reaching millions of consumers. 

In a statement, Lilly defended the ads and pointed to what it says is the only trial comparing the company’s respective drugs.

“Rather than compete on the merits of its products, Novo is asking a court to stop Lilly from communicating the results of that trial,” Eli Lilly’s statement reads. “We stand firmly behind our advertising. It is truthful, it is transparent, and it is grounded in the most direct scientific evidence available — exactly what patients deserve. We will continue to focus on the science and defend against this lawsuit vigorously.”

Novo Nordisk is seeking a permanent injunction requiring Eli Lilly to pull the advertising across all platforms, and to conduct a corrective advertising campaign. If Lilly doesn’t voluntarily pull the ads, Novo said it intends to file a formal motion in the coming days seeking a preliminary injunction. 

“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,” Novo Nordisk’s senior vice president and group general counsel, John Kuckelman, said in a statement. 

The company sent Lilly a formal cease-and-desist request after the U.S. approved a 7.2-milligram dose of Wegovy but said it received no response. 

Novo and Lilly are locked in a fierce battle for dominance in the lucrative U.S. obesity drug market, and the lawsuit marks a significant escalation. Analysts expect the market to be worth more than $100 billion by 2030. 

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