A highly anticipated cholesterol drug from Novartis failed to reduce the risk of severe cardiovascular outcomes in a Phase 3 study, dealing a blow to the company and others exploring a new approach to prevent cardiovascular disease.

The company said that the drug didn't reduce the risk of cardiovascular events-including deaths, heart attacks and strokes-compared with a placebo. But it did succeed in lowering levels of lipoprotein(a), a fatty particle in the blood known as Lp(a), Novartis said.

The results advance "scientific understanding of the relationship between Lp(a) lowering and cardiovascular outcomes and may help inform future approaches to cardiovascular risk management," said Shreeram Aradhye, the Swiss drugmaker's chief medical officer.

The hope had been that the drug-called pelacarsen-would take on an insidious cause of heart attacks and strokes that has eluded treatment for decades. Tens of millions of people in the U.S. have elevated Lp(a), an inherited and largely hidden driver of heart disease. Travis DeMaria, a real-estate broker from Ontario, Canada, who has high levels of Lp(a) had been closely following the trial. DeMaria, who is on a low-dose statin and other medications, has taken steps to control other risk factors such as his LDL cholesterol since he learned about his elevated Lp(a) levels.

"There is a lot more to learn about Lp(a) and how it affects the body," said DeMaria, 37.

For years, scientists believed that lowering Lp(a), a cousin of LDL cholesterol, would reduce plaque buildup and lead to fewer heart attacks and strokes. This trial was a major test of that hypothesis.

"There's been a lot of evidence that lipoprotein(a) might be a missing link," said Kushal Kadakia, a physician at Massachusetts General who studies cardiovascular drugs. "It's really surprising and a setback for the field to see a result like this."

Pelacarsen was initially discovered and developed by Ionis Pharmaceuticals. In 2019, Novartis exercised an option to license development and commercialization rights for the drug.

Amgen and Eli Lilly are developing similar therapies but use a different technology that aims to silence the gene producing Lp(a). Novartis and Ionis's product is based on technology blocking the signal that tells the liver to produce Lp(a).

Shares of Novartis fell more than 4% in after-hours trading on Friday. Ionis shares fell more than 10%.

Novartis didn't share more details on the trial outcomes but plans to present the data at a coming medical conference.