People with high triglycerides may soon have a new treatment option after researchers reported impressive results from a large international clinical trial.
Triglycerides are a type of fat found in the blood, and high levels are linked with a greater risk of heart disease, stroke, and other serious health problems.
The new medicine, called olezarsen, reduced these blood fat levels far more than a placebo and may become an important treatment for people at high cardiovascular risk.
The findings were presented at the ESC Congress 2025 and were also published in the American Heart Journal.
The study was led by Dr. Brian Bergmark from Brigham and Women’s Hospital at Harvard Medical School. It formed part of the ESSENCE-TIMI 73b clinical trial, which was designed to test both the effectiveness and safety of olezarsen.
Triglycerides are an important source of energy, but having too much of this fat in the bloodstream can damage blood vessels over time. High triglyceride levels are especially common in people with diabetes, obesity, metabolic syndrome, and unhealthy lifestyles. Although medicines and healthy lifestyle changes can lower triglycerides, many people still struggle to reach healthy levels.
The study included more than 1,300 adults from North America and Europe who had moderately raised triglyceride levels. Most participants either already had heart disease or had diabetes and were older than 55, placing them at high risk of future heart problems. All participants continued taking their usual cholesterol-lowering treatment during the study.
Participants were randomly assigned to receive either a 50 mg injection of olezarsen, an 80 mg injection, or a placebo with no active medicine. The injections were given once every four weeks for one year. This type of study design helps researchers compare treatments fairly and reduce the chance that the results are influenced by other factors.
After six months, both doses of olezarsen produced large reductions in triglyceride levels. Compared with the placebo group, triglycerides fell by about 58.4% in the 50 mg group and 60.6% in the 80 mg group.
More than 85% of people receiving olezarsen reached triglyceride levels below 150 mg/dL, which is considered a healthy target, while only 12.5% of people receiving the placebo achieved the same result.
The improvements lasted throughout the year-long study. Olezarsen also reduced several other harmful blood fats, including remnant cholesterol, non-HDL cholesterol, and apolipoprotein B, all of which are linked with cardiovascular disease. However, it did not significantly change LDL cholesterol, often called ‘bad’ cholesterol.
The treatment was generally well tolerated. Serious side effects occurred at similar rates in the treatment and placebo groups. Some people receiving olezarsen experienced small increases in liver enzyme levels, but these changes were usually mild and did not lead to major health problems.
The researchers believe these findings are encouraging because current treatments often do not lower triglycerides enough in people at high risk of heart disease. Dr. Bergmark said the results were stronger than those usually seen with existing medicines, suggesting olezarsen could become an important new option if future studies continue to confirm its benefits and safety.
Although the results are promising, more research is still needed before olezarsen becomes widely available. Larger studies will help determine whether lowering triglycerides with this medicine also reduces the number of heart attacks, strokes, and deaths.
Until then, maintaining a healthy diet, exercising regularly, controlling diabetes, avoiding smoking, and following medical advice remain essential for protecting heart health.
If you care about heart health, please read studies about the best time to take vitamins to prevent heart disease, and scientists find how COVID-19 damages the heart.
For more health information, please see recent studies about Aspirin linked to higher risk of heart failure, and results showing Blackcurrants could improve artery functions, blood pressure in older people.
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