Novo Nordisk has escalated its legal fight against Eli Lilly, notifying a federal court of plans to seek a preliminary injunction blocking certain rival obesity drug advertisements.
The Danish pharmaceutical giant filed its notice days after launching a lawsuit in New Jersey accusing Lilly of deploying “deliberately false” messages comparing the two companies’ GLP-1 treatments.
Novo plans to file a motion for the preliminary injunction on August 17, targeting what it describes as “false and misleading” direct-to-consumer advertising campaigns for Lilly’s weight loss and diabetes drugs.
At the centre of the dispute are two Lilly promotional campaigns claiming its obesity drug Zepbound produces “significantly more” weight loss than Novo’s Wegovy and that Mounjaro reduces A1C “significantly more.”
Novo alleges that Lilly’s advertising inaccurately compared competing drugs by using mismatched dosages, which it says creates a misleading picture for consumers across the United States.
“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,” said John Kuckelman, Novo Nordisk’s senior vice president and group general counsel.
Novo says it sent Lilly a cease-and-desist letter in April following US approval of a 7.2 mg dose of Wegovy, but received no substantive response and instead saw Lilly insert what Kuckelman called an inadequate disclaimer into its advertisements.
Beyond the injunction, Novo is seeking a court order requiring Lilly to withdraw the disputed ads and run a corrective advertising campaign, as well as damages including profits attributable to the challenged promotions.
Lilly pushed back strongly, with a spokesperson arguing that “head-to-head clinical trials are the strongest evidence for comparing medicines” and defending the SURMOUNT-5 and SURPASS-2 trials as the gold standard for comparing its tirzepatide treatments against Novo’s semaglutide.
Lilly said it stands “firmly behind our advertising” and that the “gold standard for comparing medicines is a robustly designed, well-conducted head-to-head clinical trial,” vowing to vigorously defend itself against the lawsuit.
The courtroom battle reflects the fierce commercial rivalry between the two pharmaceutical giants as they compete for dominance in the obesity drug market, which analysts expect to be worth more than $100 billion by the end of this decade in the United States alone.
BMO analyst Evan Seigerman described the lawsuit as an effort by Novo to shape public perception of how the two companies’ drugs perform against one another.
“What it shows from my perspective is that Novo is taking a more aggressive stance in managing its business, they’re not just going to let Lilly say whatever they want,” Seigerman said.
Sven Borho, managing partner at Orbimed, offered a more critical view of Novo’s strategy, suggesting the company should instead focus on its pipeline and noting that “Lilly has been outcompeting them on the R&D front as well.”
While patent infringement suits are commonplace in the pharmaceutical industry, false advertising claims of this nature between major rivals remain considerably less common in the sector.
Copenhagen-listed Novo Nordisk shares fell 2% in afternoon trading following the news, while Lilly shares edged marginally higher, rising 0.5%.