MSD’s verubecestat fails in Phase 3 Alzheimer’s trial

US pharma giant Merck & Co has halted a Phase III trial of verubecestat (MK-8931) in people with prodromal Alzheimer’s disease (AD) based on a recommendation by the external Data Monitoring Committee (eDMC).

Verubecestat is a small molecule inhibitor of the beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) and it had been seen as a promising prospect even in the graveyard of hopeful candidates that is the Alzheimer’s drug development space.

Merck’s clinical development program linked verubecestat to lower levels of beta-amyloid. But in two phase 3 trials that enrolled thousands of patients it failed to show the drug also improves outcomes. The phase 3 failures sees verubecestat join the list of BACE drugs that have stumbled in the clinic. Eli Lilly and Roche both scrapped BACE1 inhibitors in 2013.