Adding Amgen's cholesterol drug Repatha to standard therapy reduced major cardiovascular events by 25% for at-risk patients who have never had a heart attack or stroke, according to results from a large study presented on Saturday.

In the study of more than 12,000 patients, detailed at the American Heart Association scientific meeting in New Orleans, the injected drug cut the risk of a first heart attack by 36%.

The results mark the first time a drug in a class known as PCSK9 inhibitors was proven to be effective in primary prevention, opening its use to more patients, Amgen research and development chief Jay Bradner said in an interview.

Repatha also reduced the relative risk of cardiovascular death by 21% in the trial, although that result was not deemed statistically significant.

The U.S. Food and Drug Administration in August broadened Repatha's approval to include adults at increased risk of major cardiovascular events due to uncontrolled "bad" LDL cholesterol, removing a prior requirement for a patient to be diagnosed with cardiovascular disease.

"Having the label is wonderful, but having the data is important," Bradner said, noting that health insurers and other payers need those details for determining coverage.

Repatha targets PCSK9, a protein that maintains LDL cholesterol in the blood, and helps people who don't benefit from older statin pills, which block the liver's production of bad cholesterol.

Sales of the drug, first approved in 2015, grew 33% from a year earlier to total $2.15 billion in the first nine months of 2025.

Amgen last month launched direct-to-consumer sales of Repatha for U.S. cash-paying patients at $239 a month, or nearly 60% below the drug's $573 list price.

Rivals are developing PCSK9 pills. Merck will present later at the AHA meeting data on its experimental daily oral drug enlicitide decanoate, including results from a Phase 3 trial in adults with high cholesterol and a history of a major cardiovascular event such as a heart attack or stroke.