The National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health has stopped a clinical trial studying a blood lipid treatment 18 months earlier than planned.
The trial found that adding high dose, extended-release niacin to statin treatment in people with heart and vascular disease, did not reduce the risk of cardiovascular events, including heart attacks and stroke.
Participants were selected for AIM-HIGH because they were at risk for cardiovascular events despite well-controlled low-density lipoprotein (LDL or bad cholesterol). Their increased risk was due to a history of cardiovascular disease and a combination of low high-density lipoprotein (HDL or good cholesterol) and high triglycerides, another form of fat in the blood. Low HDL and elevated triglycerides are associated with an increased risk of cardiovascular events. While lowering LDL decreases the risk of cardiovascular events, it has not been shown that raising HDL similarly reduces the risk of cardiovascular events.
During the study’s 32 months of follow-up, participants who took high dose, extended-release niacin and statin treatment had increased HDL cholesterol and lowered triglyceride levels compared to participants who took a statin alone. However, the combination treatment did not reduce fatal or non-fatal heart attacks, strokes, hospitalizations for acute coronary syndrome, or revascularization procedures to improve blood flow in the arteries of the heart and brain.
“Seeking new and improved ways to manage cholesterol levels is vital in the battle against cardiovascular disease,” said Susan B. Shurin, M.D., acting director of the NHLBI. “This study sought to confirm earlier and smaller studies. Although we did not see the expected clinical benefit, we have answered an important scientific question about treatment for cardiovascular disease. We thank the research volunteers whose participation is key in advancing our knowledge in this critical public health area, and the dedicated investigators who conducted the study.”
The AIM-HIGH trial, which stands for Atherothrombosis Intervention in Metabolic Syndrome with Low HDL/High Triglycerides: Impact on Global Health, enrolled 3,414 participants in the United States and Canada with a history of cardiovascular disease who were taking a statin drug to keep their LDL cholesterol low. Study participants also had low HDL cholesterol and high triglycerides, which meant that they were at significant risk of experiencing future cardiovascular events. Niacin, also known as Vitamin B3, has long been known to raise HDL and lower triglycerides. Eligible participants were randomly assigned to either high dose, extended-release niacin (Niaspan) in gradually increasing doses up to 2,000 mg per day (1,718 people) or a placebo treatment (1,696 people). All participants were prescribed simvastatin (Zocor), and 515 participants were given a second LDL cholesterol-lowering drug, ezetimibe (Zetia), in order to maintain LDL cholesterol levels at the target range between 40-80 mg/dL.
The NHLBI funded the AIM-HIGH study with additional support from Abbott Laboratories, a pharmaceutical company based in Abbott Park, Ill. Abbott also provided Niaspan and Merck Pharmaceuticals, based in Whitehouse Station, N.J., provided Zocor. All drugs used in the study were approved for marketing in the United States and Canada and have been on the market for many years.
Source: National Heart, Lung and Blood Institute, USA