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.

Eli Lilly shares dropped Thursday as Novo Nordisk notched a coverage win for its obesity drug, a sign of the competition in the weight loss field.

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.