Shares of Novo Nordisk slumped 9%.

Shares of Novo Nordisk tumbled on Friday after the healthcare giant said that a drug it was developing to treat heart disease, kidney disease and inflammation failed in a late-stage trial.

The Danish company announced in a statement on Friday that its ZEUS trial, which involved 6,300 patients, evaluated ziltivekimab, a monoclonal antibody that targets the IL-6 protein, versus placebo for reducing the risk of deaths related to cardiovascular health as well as nonfatal heart attacks and strokes.

Novo Nordisk's stock in New York (NVO) fell 9%. Shares on Copenhagen's Stock Exchange (DK:NOVO.B) slipped almost 8% on the news.

According to the drugmaker, while the experimental medication was able to attach to the IL-6 target, which is responsible for communicating with the immune system, it didn't lead to a reduction in the risk of major heart and blood vessel issues in people with atherosclerotic cardiovascular disease - which involves the buildup of plaque in the arteries - chronic kidney disease and inflammation.

"ZEUS was designed to test whether inhibition of the IL-6 pathway could translate reductions in cardiovascular inflammation into fewer major cardiovascular events," Martin Holst Lange, executive vice president, chief scientific officer and head of research and development at Novo Nordisk, said. "Although ziltivekimab produced the expected biological effect, this did not result in MACE [Major Adverse Cardiovascular Events] benefits in this population."

The company said the overall number of adverse heart events and serious cardiovascular events among people treated with the medication was roughly the same as among those where placebo was used.

It added that more people treated with ziltivekimab had serious infections, but that was consistent with aiming for IL-6 inhibition. Novo Nordisk found no difference in mortality cases between the two treatments.

The company said the failed trial would not affect current forecasts for operating profit for the full year, but said it would lead to a noncash impairment charge in the current quarter.

Novo Nordisk expects operating profit to decline by between 4% and 12% at constant exchange rates in 2026.

It comes as in February, the company's experimental weight-loss drug, CagriSema, failed to prove it was better than Eli Lilly's $(LLY)$ rival medication Zepbound. And in November of last year, the pill version of its Ozempic drug also failed trials after not being able to slow Alzheimer's.

-Nora Redmond