Novo Nordisk sues Eli Lilly over GLP-1 ads

Novo Nordisk on Tuesday filed a lawsuit against Eli Lilly, alleging that its advertising campaigns for its blockbuster obesity and diabetes drugs are designed to mislead consumers about their superior efficacy relative to the Danish drugmaker’s rival injections. 

Novo is specifically taking issue with nationwide ads that cite what it called “outdated” clinical trials to compare the highest doses of Lilly’s medicines to lower doses of Novo’s drugs. For example, those campaigns don’t include new evidence about Novo’s recently approved high-dose version of its obesity injection, Wegovy, which entered the market in March and brings weight loss that’s more comparable to Lilly’s products.

That “leaves them with the inevitable conclusion that Lilly’s medicines are superior to Novo’s, and that’s not accurate,” said John Kuckelman, Novo’s group general counsel, in an interview Monday. He said the suit comes after Lilly refused to pull down or correct certain ads despite a formal cease-and-desist request from Novo in April. 

In the suit filed in the U.S. District Court for the District of New Jersey, Novo asked the court to permanently stop Lilly from running the ads and require the drugmaker to issue corrective advertising. Novo is also seeking financial damages, though it’s unclear how much. The company said it has also warned Lilly that if the ads are not removed voluntarily, it plans to seek a preliminary injunction in the coming days to block them immediately while the case proceeds. 

In a statement on Tuesday, Lilly said it stands “firmly behind our advertising.” The company also said the “gold standard for comparing medicines is a robustly designed, well-conducted head-to-head clinical trial,” such as the one it uses in its ad campaigns to compare its obesity injection, Zepbound, to Wegovy. That remains the only study that directly pits those drugs against each other.

“It is truthful, it is transparent, and it is grounded in the most direct scientific evidence available — exactly what patients deserve,” Lilly said. “We will continue to focus on the science and defend against this lawsuit vigorously.”

The suit comes as Novo wages an aggressive battle against Lilly to regain market share in the GLP-1 space, positioning its new obesity pill, strategic price cuts and the new high-dose Wegovy to compete with its rival’s top-selling obesity injection Zepbound and diabetes counterpart Mounjaro.

In recent years, Lilly’s medications have become the preferred treatments in the space among many providers and patients due to their high efficacy. But high-dose Wegovy, which showed an average weight loss of around 19%, is a direct answer to that.