Eli Lilly on Thursday downplayed CVS Health's decision to drop the company's obesity drug Zepbound from some lists of medicines it covers for reimbursement, but shares of the drugmaker still fell roughly 10% on investor worries that the move could blunt its sales momentum.

Wegovy and Zepbound are part of a wave of obesity medications known as GLP-1 receptor agonists that have soared in popularity due to the amount of weight people lose while taking the injections. Coverage of these drugs has been patchy due to in part to their cost and the wide swath of patients who could take them.

CVS Health Corp.’s drug-benefits unit negotiated a deal to make Novo Nordisk A/S’s Wegovy more widely available to its members, a blow to rival Eli Lilly & Co.’s Zepbound that was moved off the company’s list of preferred drugs.