Novo Nordisk faced a pivotal setback as the Zeus Phase III trial of ziltivekimab failed to reduce major adverse cardiovascular events, despite the drug successfully engaging its target by inhibiting the IL-6 pathway and lowering free IL-6 and high-sensitivity C-reactive protein.

The trial enrolled over 6,300 patients with atherosclerotic cardiovascular disease, inflammation, and chronic kidney disease, but produced a hazard ratio of 0.99 for MACE, indicating no cardiovascular risk reduction compared with placebo.

Following the news, Novo Nordisk’s stock fell sharply, dropping around 10% intraday on the Copenhagen market and about 9-10% in U.S. premarket trading.

Management indicated that the setback will not derail the company’s broader plans, with additional business development updates anticipated and second-quarter results scheduled for early August.

First-quarter 2026 results showed strong early adoption of the obesity pill in the U.S., giving the CEO reason to anticipate a smaller decline in 2026 revenue and operating income than previously expected.

The company reaffirmed its 2026 adjusted operating profit guidance, noting a non-cash impairment will be booked in the third quarter due to the Zeus failure, though the guidance itself remains intact on an adjusted basis.

Executives stressed that the trial outcome will not alter the 2026 adjusted operating profit outlook, but will trigger a non-cash impairment charge in Q3 2026.

The setback sits within a broader context of ongoing inflammation-targeting strategies in cardiovascular prevention and the industry’s continued evaluation of such approaches.

Market reaction reflected disappointment, with Danish shares sliding and U.S.-listed ADRs down as investors reassessed the potential of inflammation-targeting therapies.

Novo Nordisk reiterated that the result does not change its long-term commitment to cardiovascular disease research and development.

Safety outcomes were broadly similar between groups, though the ziltivekimab arm showed a higher rate of serious infections.

Analysts cited by JPMorgan believe the setback removes a multi-billion-dollar revenue potential for the company.