By Xavier Martinez

A new class of drugs is poised to take on an insidious cause of heart attacks and strokes that has eluded treatment for decades.

Researchers could know as soon as this summer whether the most advanced experimental drug, from Novartis and its partner Ionis Pharmaceuticals, cut heart attacks, strokes and deaths in a study that could be used to get their drug approved by next year.

Amgen and Eli Lilly are also developing medicines that lower the level of lipoprotein(a), a fatty particle in the blood that is known as Lp(a). It can cause plaque to build up in blood vessels and is linked to heart disease.

Tens of millions of people in the U.S. have elevated Lp(a), an inherited and largely hidden driver of heart disease. If Lp(a) drugs work, companies could be on the verge of the next big heart-drug market. Citi analysts estimate it could be valued at as much as $25 billion a year worldwide.

This isn't a sure bet, though. Effective Lp(a) drugs have proven difficult to develop. In the past, scientists found drugs that lowered levels of the particle a moderate amount but failed to reduce heart attacks and strokes in research studies, leaving patients with no approved treatment.

"It's just been the riddle that nobody could solve," said Monica Florio, who has helped lead research on Amgen's candidate. "Now I think these trials are going to bring us an answer."

Lp(a) is an especially treacherous cause of heart disease. The particle is a variant of LDL, the so-called bad cholesterol. Like its cousin, high levels of buildup in arteries threaten heart attacks and strokes.

But the problem is, six decades of research has so far failed to prove that lowering a person's Lp(a) will actually reduce their risk of heart attacks and strokes. For Lp(a) drugs to work, scientists say they must significantly lower overall levels of the particle in the body.

Diet and exercise don't lower Lp(a). About 90% of a person's level is fixed at birth. Doctors usually prescribe other cholesterol treatments, such as statins, to manage overall cardiovascular risk -- yet statins can raise Lp(a) levels.

Roughly one in five people globally have dangerously high levels of Lp(a), according to Dr. Steven Nissen, a cardiologist at the Cleveland Clinic who is involved in trials to test several of the drugs in development.

Lp(a) hardens arteries and promotes clotting, which is "why it is so noxious in terms of increasing adverse cardiovascular events," Nissen said.

Drugmakers are using new technologies to attack Lp(a) now.

Both Amgen's experimental Lp(a) drug and Lilly's most advanced treatment deploy a gene-based technology that aims to silence the gene that produces Lp(a).

Amgen's late-stage trial is expected to have results in the next year or two, while Lilly's late-stage trial results aren't expected until 2029.

The therapy from Novartis and Ionis uses a different gene-based technology that blocks the signal telling the liver to produce Lp(a).

Bill Heym, who is in the Novartis trial, didn't find out that he had high levels of the particle until he suffered a heart attack.

Shortly after retiring from a 35-year career as a construction electrician, the Parma, Ohio, resident had shoulder-reconstruction surgery in late 2016.

He went into cardiac arrest while at the hospital and required three rounds of cardiopulmonary resuscitation. He was airlifted to the Cleveland Clinic's main hospital, where doctors performed an emergency procedure to remove blood clots from his arteries and heart.

When Heym woke up three days later, his doctor delivered the news: His Lp(a) level was more than triple the threshold at which the American Heart Association says it starts raising heart risk.

Most people have never had their Lp(a) level tested, according to Nissen, the Cleveland Clinic cardiologist. Doctors have been hesitant to order the test for patients because there aren't currently any approved drugs to directly lower the particle. Medical bodies updated guidelines earlier this year to recommend Lp(a) testing.

If the drugs work, the question will be who exactly should get them.

The drugs might prove clearly effective only for people with extremely high levels of Lp(a). If the benefit for patients with lower levels is murky , the drugs could end up being covered by insurers only for those at very high risk.

Then there is the question of cost: A decade ago, health plans balked at paying for powerful new cholesterol-lowering drugs called PCSK9 inhibitors because of pricing.

Drugmakers eventually slashed prices to about $200 a month from roughly $1,000 a month before insurers would cover them broadly. Analysts have estimated that the annual price for Lp(a) drugs could be similar to approved PCSK9 drugs -- but a lot depends on the coming study results.

Amgen argues that near-total elimination of the particle is what will meaningfully reduce heart attacks and deaths.

"This could prove to be important, especially in patients who benefit from decades of improving other risk-factor management," said Jay Bradner, Amgen's executive vice president for research and development.

Write to Xavier Martinez at xavier.martinez@wsj.com

(END) Dow Jones Newswires

May 27, 2026 12:00 ET (16:00 GMT)

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