Eli Lilly Drops 3.5% as Zepbound Faces Formulary Removal

Eli Lilly's stock dropped 3.5% in pre-market trading on May 12, 2025, as investors reacted to the latest developments surrounding its weight loss drug, Zepbound.

Eli Lilly recently announced that its weight loss drug, Zepbound, outperformed Novo Nordisk's Wegovy in reducing waist circumference and four other key metrics. The data showed that Zepbound helped nearly 25% of participants lose more than 15% of their body weight, with an average waist reduction of 18.4 cm, compared to Wegovy's 13 cm. Zepbound's mechanism of action, which mimics two intestinal hormones, is considered superior. This data supports Eli Lilly's efforts to secure insurance coverage, but recent actions by West Virginia Health have removed Zepbound from their formulary, shifting support to Wegovy, intensifying market competition.

Eli Lilly's Zepbound, which contains tirzepatide, a GLP/GLP-1 dual receptor agonist, has shown superior weight loss results compared to Novo Nordisk's Wegovy, which contains semaglutide, a GLP-1 receptor agonist. The study, published in the New England Journal of Medicine, revealed that participants using Zepbound lost an average of 50 pounds (22.8 kg) after 72 weeks, while those using Wegovy lost approximately 33 pounds (15 kg).

The study involved 751 participants with obesity or overweight, excluding those with diabetes. The results showed that Zepbound users had an average weight loss of 20.2%, compared to 14% for Wegovy users. Additionally, Zepbound users experienced an average waist reduction of 18.4 cm, compared to 13 cm for Wegovy users. Over 31% of Zepbound users lost at least a quarter of their body weight, compared to 16% of Wegovy users. Both drugs showed improvements in blood pressure, cholesterol, and blood sugar levels, with common side effects including mild to moderate gastrointestinal issues.