Novo Nordisk says it is suing Eli Lilly, accusing it of false advertising

Novo Nordisk said on Tuesday it was suing rival Eli Lilly in U.S. federal court, accusing the U.S. drugmaker of false advertising in claiming its weight-loss medicines outperform Novo's drugs.

The Danish company said it filed the lawsuit in U.S. District Court in New Jersey, alleging Lilly violated federal and state false advertising and unfair competition laws, including the Lanham Act, through nationwide advertising campaigns for obesity drug Zepbound and diabetes treatment Mounjaro.

Novo alleges Lilly compared the highest approved doses of its medicines with lower doses of Novo's Wegovy and Ozempic while omitting newer, higher-dose versions that Novo says deliver greater weight loss.

Novo said it is seeking a court order requiring Lilly to withdraw the advertisements and run a corrective advertising campaign. It added that it plans to seek a preliminary injunction if Lilly does not voluntarily remove the ads.

Novo said it sent Lilly a cease-and-desist letter in April after the U.S. approved a 7.2-milligram dose of Wegovy. Lilly did not respond to the letter, Novo's general counsel John Kuckelman told Reuters, adding that the company instead inserted what he described as an inadequate disclaimer into the advertisements.

Kuckelman said Lilly's advertisements compare weight-loss results of about 50 pounds for Zepbound with about 33 pounds for Wegovy, even though no head-to-head trial has compared the highest approved doses of the medicines. He said separate late-stage trials of the highest doses showed average weight loss of about 48 pounds for Zepbound and 47 pounds for Wegovy.