NEW YORK — Merck & Co. said Thursday that a combination of niacin and another medicine failed to protect against heart attacks and strokes in a large clinical trial. The drug maker will no longer pursue US approval of the combination therapy.
The trial, which followed more than 25,000 patients over four years, also found a statistically significant increase in the number of patients who suffered serious nonfatal adverse events.
The results are likely to further tarnish the reputation of niacin, a drug commonly used to raise the levels of good cholesterol in patients at risk for heart disease but which was found not to be beneficial in a government study last year.
Merck’s Tredaptive drug, combined an extended-release version of niacin with laropiprant, a medicine to reduce facial flushing, a side effect. Tredaptive is sold in about 40 countries but failed to win US approval.
Merck recommends that doctors not start new patients on the drug. The company said it would work closely with regulatory agencies ‘‘to understand the results and determine next steps.’’
Although the study did not determine that the negative results were because of niacin, the conclusions will probably further call into question whether patients should continue to be prescribed long-acting niacin.
Last year, a study by the National Institutes of Health found Niaspan offered no benefit over the use of statins, used to lower bad cholesterol.
“The failure strongly suggests that niacin simply does not improve outcomes for patients,’’ said Dr. Steven Nissen, at the Cleveland Clinic.
He will continue prescribing niacin to patients already on it who are faring well but would probably not prescribe it to new patients.