Novo Nordisk’s anti-inflammatory heart drug fails late-stage trial

Novo Nordisk’s investigational anti-inflammatory drug ziltivekimab failed to reduce major adverse cardiovascular events in a pivotal phase 3 trial of more than 6,300 patients, a setback for one of cardiology’s most closely watched ideas. The drug did not lower the risk of serious cardiovascular events, including heart attacks, strokes and death.

The result hit the company as well as the science. Novo Nordisk shares fell sharply after the data, with one account putting the drop at 10%, underscoring how much investor value had been tied to the possibility that the company could move beyond obesity drugs and into cardiovascular prevention.

The trial failure lands in a field that has spent years arguing over how much inflammation drives heart disease. The American Heart Association and Harvard Health Publishing have described inflammation as a biologically plausible contributor to atherosclerosis and cardiac risk, while peer-reviewed reviews have found that anti-inflammatory therapies in heart failure and related settings have produced largely negative or inconclusive results. Ziltivekimab’s miss does not erase the role inflammation may play, but it weakens the assumption that simply blocking one inflammatory pathway will reliably prevent heart attacks and strokes.

That distinction matters for patients and for drugmakers. Cardiovascular medicine has long leaned on the cholesterol-first model, and inflammation was increasingly being treated as a second major target. Novo Nordisk’s result suggests the biology is more complicated than a straight line from inflammation to fewer events, which could make future trials harder to design and more expensive to justify. It also raises the bar for any company hoping to build a broad cardiovascular franchise around anti-inflammatory drugs.

The failure also sits beside one of the field’s few clear successes. Colchicine, another anti-inflammatory medicine, won U.S. Food and Drug Administration approval in 2023 for reducing cardiac event risk in patients with established atherosclerotic cardiovascular disease. That approval showed the approach can work in some settings, even as broader efforts have stumbled.

Novo Nordisk still has two additional ziltivekimab trials expected in the first half of 2027, leaving its cardiovascular ambitions alive but under pressure after a result that forced a fresh look at one of heart medicine’s most persistent theories.