Novo Nordisk shares fall 9% after Phase 3 ZEUS trial fails

Shares of Novo Nordisk fell sharply on Friday, July 31, 2026, after the Danish pharmaceutical company announced that its experimental heart drug ziltivekimab failed to meet its primary goal in a major Phase 3 clinical trial. The stock dropped more than 9% following the news, which deals a significant blow to the company's ambitions to expand beyond its blockbuster diabetes and weight-loss treatments.

The trial, named ZEUS, enrolled more than 6,300 patients with atherosclerotic cardiovascular disease, chronic kidney disease, and elevated inflammation. Participants received either a once-monthly 15 mg injection of ziltivekimab or a placebo on top of standard care. The drug, designed to inhibit the interleukin-6 (IL-6) inflammatory pathway, successfully lowered levels of free IL-6 and high-sensitivity C-reactive protein, confirming its intended biological effect. However, this reduction in inflammation did not translate into a lower risk of major adverse cardiovascular events, a composite measure including cardiovascular death, non-fatal heart attack, and non-fatal stroke. The hazard ratio was 0.99, indicating virtually identical risk between the treatment and placebo groups.