Key Highlights
- Novo Nordisk initiated legal proceedings against Eli Lilly in New Jersey’s U.S. District Court this Tuesday
- The complaint alleges Lilly’s marketing campaigns for Zepbound and Mounjaro rely on obsolete clinical trial data to suggest superiority
- Eli Lilly’s promotional materials compare maximum doses of its products against lower-strength versions of Wegovy and Ozempic, deliberately omitting recent high-dose results
- According to Novo, the high-strength Wegovy formulation (7.2mg) demonstrates approximately 47 pounds of average weight reduction, nearly matching Zepbound’s roughly 48 pounds
- Novo seeks judicial orders to remove the advertisements, mandate corrective marketing, and award monetary compensation
Shares of Novo Nordisk (NVO) declined approximately 1.4% while Eli Lilly (LLY) fell roughly 2.7% on Tuesday following Novo’s filing of a complaint alleging deceptive promotional practices for Lilly’s weight management pharmaceuticals.
The legal action was initiated in the United States District Court for the District of New Jersey. Novo alleges violations of the Lanham Act, alongside various federal and state regulations governing false advertising and anti-competitive practices.
Central to the dispute are extensive television and digital media campaigns promoting Lilly’s weight management medication Zepbound and its diabetes therapeutic Mounjaro.
According to Novo’s allegations, these promotional materials leverage antiquated clinical research to portray Lilly’s products favorably. A television advertisement that has accumulated more than 700 million views since late April claims Zepbound users experience an average 50-pound weight reduction compared to 33 pounds with Wegovy.
Novo contends the issue lies in the fact that the 33-pound statistic derives from studies utilizing lower-strength Wegovy formulations ā specifically excluding the recently approved 7.2-milligram dosage that received regulatory clearance in March 2025.
According to Novo’s data, the high-strength Wegovy formulation demonstrated average weight reduction of approximately 47 pounds in contemporary clinical trials. This figure closely approximates Zepbound’s 48-pound result from Lilly’s most current research.
“It leaves them with the inevitable conclusion that Lilly’s medicines are superior to Novo’s, and that’s not accurate,” stated John Kuckelman, Novo’s group general counsel.
Lilly Disregarded Initial Legal Warning
Novo indicates this dispute has a history. The pharmaceutical company dispatched a formal cease-and-desist notification to Lilly in April, shortly following the high-dose Wegovy authorization.
Lilly declined to withdraw the promotional materials. According to Novo, the company instead incorporated what it describes as an “ambiguous, confusing, virtually illegible” footnote referencing the higher-dose formulation’s existence ā without clearly communicating its enhanced efficacy.
Novo now requests the court issue a permanent injunction blocking the advertisements, compel Lilly to conduct corrective promotional campaigns, and award monetary damages. Should Lilly refuse voluntary removal of the promotional materials, Novo indicates it will pursue a preliminary injunction for immediate withdrawal pending litigation resolution.
Lilly has not issued a response to media inquiries regarding the matter.
Ozempic and Mounjaro Comparison Also Under Scrutiny
The legal complaint extends beyond Zepbound and Wegovy comparisons. Novo additionally contends Lilly employed identical methodology when contrasting Mounjaro against Ozempic ā suppressing information about a higher-strength Ozempic formulation that received approval more than four years ago.
Direct comparative clinical trials evaluating the maximum approved dosages of Wegovy and Zepbound have not been conducted. Novo argues this absence means Lilly possesses “no basis” for asserting its pharmaceuticals demonstrate superior effectiveness compared to Novo’s current product portfolio.
“While it may have been accurate to say that before 7.2 milligrams became available for Wegovy, it is no longer accurate to say that,” Kuckelman said.
The Zepbound television commercial referenced has generated over 700 million impressions since beginning broadcast circulation near the conclusion of April.
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