A large clinical trial that compared extended-release niacin and laropiprant plus statin therapy with statin therapy alone was halted because it failed to meet its primary endpoint.

Merck announced that the combination extended-release niacin and laropiprant (Tredaptive or Cordaptive) did not significantly further reduce the risk of the combination of coronary deaths, nonfatal heart attacks, strokes or revascularizations compared with statin therapy. In addition, there was a statistically significant increase in the incidence of some types of nonfatal serious adverse events in the group that received extended-release niacin/laropiprant.

The HPS2-THRIVE (Heart Protection Study 2-Treatment of HDL to Reduce the Incidence of Vascular Events) trial enrolled 25,673 patients considered to be at high risk for cardiovascular events. Of those enrolled, 14,741 were from the United Kingdom and Scandinavia and 10,932 were from China. Patients in the study were followed for a median of 3.9 years.

Tredaptive and Cordaptive have been approved in approximately 70 countries, including in Europe, and are sold in approximately 40 countries. Whitehouse Station, N.J.-based Merck said that it is preparing communications to healthcare providers in countries where the medicine is available, and will continue to work with regulators to provide updated information to healthcare providers. Based on the current understanding of these new data and until further analyses can be completed, Merck is recommending that providers not start new patients on Tredaptive.

Merck does not plan to seek FDA approval for the medicine in the U.S.

The pharma giant said it will share results from the study with regulatory agencies in countries where the medicine is approved and in other countries as well. Investigators are conducting additional analyses, including regional analyses, to further understand the results. They anticipate reporting results in the first quarter of 2013.