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 (NVO, Financial) shares fell 8% on Monday morning following disappointing Phase 3 trial results for its weight loss drug CagriSema. The Redefine 2 trial

Novo’s share price fell 8 per cent on Monday, having previously dived in December after a late-stage trial of CagriSema in overweight or obese people without diabetes found they lost an average of 22.7 per cent of their body weight. That was only marginally ahead of results for Mounjaro, an existing rival treatment made by Eli Lilly.

Novo Nordisk said on Monday its experimental next-generation drug CagriSema helped overweight or obese patients with type 2 diabetes cut their weight by 15.7% after 68 weeks, but shares fell, likely on the lower-than-expected weight loss.

Novo Nordisk A/S shares fell the most since December after the drugmaker’s next-generation shot CagriSema showed 15.7% weight loss in a clinical trial of people with diabetes.