Washington: Merck's Lipfendra, the first oral medication designed to block the PCSK9 protein, has been approved in the United States, offering high-risk patients a pill-based alternative to injectable cholesterol-lowering therapies.

The once-daily tablet is intended for people whose artery-clogging LDL ("bad") cholesterol remains high despite taking statins, the standard drugs used to reduce the risk of heart attacks and strokes.

Until now, medicines targeting the PCSK9 protein have only been available as injectable treatments, including products made by Amgen and other manufacturers. While highly effective, those therapies have seen limited use because of their high cost, insurance restrictions and relatively low prescribing rates.

PCSK9 limits the body's ability to remove cholesterol from the bloodstream. By blocking the protein, Lipfendra helps the liver clear more LDL cholesterol, significantly reducing cardiovascular risk.

Merck secured approval after two clinical trials involving high-risk patients who took the pill alongside their existing cholesterol-lowering treatment, including statins.

In one study involving about 3,000 patients, participants taking Lipfendra reduced their LDL cholesterol by more than 55% after six months. A second study showed an average 59% reduction compared with patients receiving a placebo.

Researchers found that the cholesterol-lowering effect remained largely consistent after one year. Reported side effects, including dizziness and diarrhoea, occurred at rates similar to those seen in patients taking a placebo. The medication must be taken on an empty stomach.

Statins remain the cornerstone of cholesterol treatment by reducing the liver's production of cholesterol. However, many patients, even on the highest doses, require additional therapy to reach recommended LDL targets.

Heart disease remains the leading cause of death in the United States. High LDL cholesterol contributes to the buildup of plaque in arteries, increasing the risk of heart attacks and strokes. While an LDL level below 100 is generally considered healthy, doctors recommend reducing it to 70 mg/dL or lower for people with heart disease or high cardiovascular risk, with even lower targets for the highest-risk patients.

The US Food and Drug Administration approved Lipfendra under its expedited review programme for promising medicines considered to serve the public interest.