Merck & Co has told partner Arena Pharmaceuticals that it intends to discontinue development of an investigational atherosclerosis drug which has disappointed in a mid-stage trial.

The New Jersey-based giant made the decision to discontinue development of MK-1903, an investigational niacin receptor agonist, after reviewing results of a recently completed Phase IIa trial in patients with dyslipidemia. According to Merck, elevation of HDL, or ‘good’, cholesterol relative to placebo did not meet the trial's primary objective for efficacy but Arena stresses that “no safety signals were implicated as drivers of the decision to discontinue development”.

Jack Lief, Arena's chief executive, said that “we are disappointed that the trial results did not lead to further development of this programme, but it has been a pleasure to work with Merck and we welcome the opportunity to collaborate again”. He added that his firm will now focus on getting US Food and Drug Administration approval of its late-stage obesity treatment lorcaserin.