Shares in Danish drug maker Novo Nordisk (NOVO B), known for its blockbuster drugs Ozempic and Wegovy, fell roughly 20% on Friday after it released the results of a clinical trial for the experimental obesity drug CagriSema.

CagriSema helped patients lose an average of 22.7% of their body weight in a late-stage trial, missing the goal for an average of 25% weight loss. The result was only marginally better than the average weight loss of 20.2% of Zepbound, a rival treatment from Eli Lilly LLY. Eli Lilly stock rose following the news.

The phase 3 study included around 3,400 people with a BMI above 30 or BMI above 27 combined with some weight-related morbidity.

Analysts at Berenberg concluded in a survey in late September that if CagriSema is equivalent to Zepbound’s figure of 20% average weight loss, the share price reaction would be hard to predict, with a share price reaction in this scenario ranging from -20% to +5%. The market reacted even stronger initially, but recovered the fall slightly to -20% about an hour after the news.

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