Merck has decided to discontinue development of MK-1903, an investigational niacin receptor agonist to treat atherosclerosis, which it has been developing under research collaboration with Arena Pharmaceuticals.

The decision to discontinue development follows the evaluation of a recently completed Phase IIa clinical trial, which evaluated the drug’s safety, tolerability and potential efficacy in patients with dyslipidemia.

According to Merck, elevation of HDL cholesterol relative to placebo did not meet the trial’s pre-specified primary objective for efficacy. No safety signals were implicated as drivers of the decision to discontinue development.

Arena’s president and CEO Jack Lief said that the company is disappointed that the trial results did not lead to further development of this programme.

“We continue to focus on our other internal and partnered programmes and the Food and Drug Administration approval of our lead drug candidate, lorcaserin for weight management,” Lief said.