Clinical Trial of BACE Inhibitor Elenbecastat for Treating Early Alzheimer’s Disease Discontinued

Phase 3 clinical studies of the investigational oral ß-amyloid cleaving enzyme (BACE) inhibitor elenbecestat (Eisai,Tokyo, Japan and Biogen, Cambridge, MA) for treatment of early Alzheimer’s disease (AD) have been discontinued. The Data Safety Monitoring Board (DSMB) recommended that the trials be stopped because of an unfavorable risk-benefit profile.  

Together, the MISSIONAD 1 and 2 clinical trials (NCT02956486 and NCT03036280) involved 2,100 participants with mild cognitive impairment (MCI) or mild AD with confirmed amyloid pathology in the brain. Both placebo-controlled, double-blind trials had identical protocols designed to assess the efficacy and safety of elenbecestat. Participants were randomly assigned to receive 50 mg/day of elenbecestat or placebo for 24 months. The planned primary endpoint was the Clinical Dementia Rating Sum of Boxes (CDR-SB). 

“We are very disappointed with the news, and intend to learn from these data and continue engaging with patients and investigators to pursue the discovery of new medicines for Alzheimer’s disease,” said Lynn Kramer, MD, chief clinical officer, neurology business group, Eisai. “We would like to thank the patients and the families, as well as medical professionals, who participated in the MISSIONAD studies. Without their contributions, we would not be able to advance Alzheimer’s disease research.”