Plunges 9% After ZEUS Heart Trial Misses Key Goal

TLDR

• Novo Nordisk stock plunges over 9% after ZEUS misses its key heart trial goal.

• ZEUS shows lower inflammation but no reduction in major cardiovascular events.

• Ziltivekimab records a 0.99 hazard ratio against placebo in the phase 3 trial.

• Serious infection rates rise with treatment while overall mortality stays level.

• HERMES and ARTEMIS continue with key trial results expected during early 2027.

Novo Nordisk stock plunged 9.18% to $46.85 after its ZEUS heart trial failed to reduce major cardiovascular events. The setback weakened confidence in ziltivekimab, despite clear biological activity against inflammation linked to cardiovascular disease and kidney damage. However, the result will not change Novo Nordisk’s adjusted operating profit outlook for the full 2026 financial reporting year.

Novo Nordisk A/S, NVO

ZEUS Trial Misses Main Cardiovascular Goal

Novo Nordisk tested ziltivekimab in more than 6,300 people with cardiovascular disease, kidney disease, and persistent systemic inflammation. The phase 3 study compared a monthly 15-milligram dose against placebo under controlled, double-blind trial conditions throughout the study. Researchers measured cardiovascular death, non-fatal heart attacks, and non-fatal strokes as the combined primary trial outcome for efficacy.

Ziltivekimab reduced free interleukin-6 and high-sensitivity C-reactive protein, confirming strong target engagement across the entire treated patient group. Those biological changes failed to lower major adverse cardiovascular events against placebo during the extended trial period. The reported hazard ratio reached 0.99, with a 95% confidence interval ranging from 0.88 to 1.11.

Overall adverse events and serious adverse events remained broadly similar between the active treatment and placebo groups. Still, serious infections occurred more often among people receiving ziltivekimab, matching the expected effects of IL-6 pathway inhibition. Meanwhile, Novo Nordisk found no meaningful difference in overall mortality between the two large study groups during follow-up.

Novo Nordisk Keeps Broader Heart Program Moving

Novo Nordisk will continue two other cardiovascular outcome trials involving ziltivekimab despite the disappointing ZEUS result. The HERMES study tests the drug in people living with heart failure and continuing cardiovascular risk. Meanwhile, ARTEMIS evaluates ziltivekimab in patients recovering after an acute heart attack and facing further complications.

Both studies should report headline results during the first half of 2027, according to the company’s current development timeline. Their designs target different cardiovascular settings, which may produce outcomes that differ materially from the ZEUS trial population. Therefore, Novo Nordisk still retains important clinical readouts before deciding the experimental medicine’s longer-term development future.

The ZEUS result will trigger a non-cash impairment charge during the third quarter of the 2026 financial year. However, Novo Nordisk said the charge will not alter its previously issued adjusted operating profit guidance for 2026. The stock decline reflects concern over pipeline value after the major trial missed its central cardiovascular objective.