Novo Nordisk on Monday revealed weaker-than-expected data from a second late-stage trial of its obesity drug candidate CagriSema, knocking shares and stoking worries that rival Eli Lilly may be gaining an edge over the company in the weight-loss drugs market.

Novo Nordisk stock tumbled Monday morning after disappointing trial results for its CagriSema weight-loss drug. Shares in rival Eli Lilly also sold off. Find out more:

The setback comes at a crucial time for Novo Nordisk, which had positioned CagriSema as its next-generation weight-loss treatment. The current generation, made up of blockbuster drugs like Wegovy and Ozempic, have been cash cows for Novo.