Lilly on Friday denied any wrongdoing, saying it stood by its advertising and would vigorously defend itself.
Novo and Lilly are battling for dominance in the obesity drug market, which analysts expect to be worth more than $100 billion by the end of the decade in the United States alone.
Novo said in a statement on Friday that Lilly’s ads were based on “outdated studies”, giving a false impression that the U.S. firm’s drugs are vastly superior.
“Novo Nordisk is seeking a court order on an expedited basis to ensure people can access the accurate, complete picture of the treatments available to them today,” it said.
Novo’s lawsuit alleges that Lilly violated false advertising and unfair competition laws through its campaigns for obesity drug Zepbound and diabetes treatment Mounjaro.
Novo claimed Lilly compared the highest approved doses of Zepbound and Mounjaro with lower doses of Novo’s Wegovy and Ozempic while omitting newer, higher-dose versions of Novo’s medicines that it says deliver greater weight loss. “Novo Nordisk has never tested its highest doses of semaglutide against Lilly’s tirzepatide medicines in any clinical trial; instead, it is using a lawsuit to advance comparisons it has never put to the test,” a Lilly spokesperson told Reuters on Friday.
Novo’s lawsuit seeks a permanent injunction requiring Lilly to withdraw the campaigns and conduct corrective advertising.
BMO analyst Evan Seigerman said the lawsuit was a way for Novo to try to change public perception of how the two companies’ drugs perform.
“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, said Novo should focus on its pipeline, adding that “Lilly has been outcompeting them on the R&D front as well”.
“Going to court is not going to help them in their marketing battle,” said Borho, whose firm manages the portfolio of Lilly shareholder Worldwide Healthcare Trust, which also owned a short-term position in Novo until May.