NEW YORK—Novo Nordisk filed a lawsuit against Eli Lilly, accusing Eli Lilly of misleading advertising in the U.S. obesity drug market. The complaint targets Lilly's Zepbound and Mounjaro advertising campaigns. Novo Nordisk alleges the ads rely on outdated weight-loss comparisons against its drugs, Wegovy and Ozempic.
Eli Lilly shares were 0.6 percent lower in premarket trading. Novo Nordisk shares fell 2 percent in Copenhagen following the lawsuit filing. The legal action intensifies competition in a global obesity market projected to reach $120 billion annually by 2030.
The lawsuit, filed in U.S. federal court in New Jersey, specifically targets a Lilly ad that began airing in April. This advertisement references the Surmount-5 study, saying individuals using Zepbound lost an average of 50 pounds. The ad compares this to an average 33-pound loss for Wegovy users.
Novo Nordisk argues this comparison uses a lower dose of Wegovy than what is available. The Food and Drug Administration approved a higher dose of Wegovy, which is triple the previous highest dose, in March. Novo Nordisk began marketing this higher-dose shot in April.
Novo Nordisk contends a more accurate comparison would show its high-dose Wegovy achieving an average 47-pound weight loss. This compares with Zepbound's average 48-pound loss in separate studies. The company has not yet shared data on patient uptake for the new triple-dose Wegovy.
The complaint also addresses Lilly's ads for its diabetes drug, Mounjaro. Novo Nordisk claims the ads incorrectly suggest Mounjaro reduces blood sugar more than Ozempic. This claim, Novo Nordisk said, is based on a comparison to a lower dose of Ozempic from a 2021 study called Surpass-2.
Novo Nordisk seeks an order from the court to halt Lilly's advertisements immediately. The company also requests "corrective advertising" and the recovery of lost profits. John Kuckelman, Novo's general counsel, said, "They've already polluted the water, so to speak, and now it needs to be cleaned up."
Novo Nordisk is also seeking triple its lost profits under U.S. law. This lawsuit follows a cease-and-desist letter Novo Nordisk sent to Eli Lilly in April. Lilly did not respond to that letter, according to Kuckelman. Instead, Lilly added a disclaimer to its ad acknowledging the higher Wegovy dose was not available at the time of the study.
The legal tactics are part of Novo Nordisk's strategy to regain market share in the lucrative weight-loss drug market. While Novo Nordisk was first to market with Wegovy, Eli Lilly has caught up with Zepbound. Lilly now leads sales for these obesity medications.
Separately, Eli Lilly increased its fight against unauthorized versions of its investigational weight-loss drug, retatrutide. The drugmaker filed six new lawsuits against U.S. sellers. Defendants include compounding pharmacies, medical spas and online vendors.
Retatrutide remains an investigational Phase 3 drug, according to Eli Lilly. The company has also challenged the Food and Drug Administration in federal court. Lilly argues the FDA is interpreting rules too narrowly regarding retatrutide's regulatory status.
Novo Nordisk has worked to regain market share. The Danish drugmaker formed partnerships with telehealth companies. It also rolled out a new weight-loss pill that has gained popularity with patients.
