The data monitoring committee gave its blessing to a far larger trial involving almost 2000 patients after examining interim safety data from a mid-stage trial of 200 patients who had been treated with the medicine, called MK-8931, for at least three months, Merck said.
The medicine works by blocking an enzyme called BACE that is involved in the production of beta-amyloid, a protein that creates plaques in the brains of people with Alzheimer's disease.
BACE inhibition is considered the most promising new approach to slowing progression of Alzheimer's disease, after other efforts to directly block beta amyloid have failed or fallen short in trials conducted by Pfizer Inc., Eli Lilly and Co. and other drug makers.