Discontinuation of Phase III Clinical Studies by Eisai And Biogen Of BACE Inhibitor Elenbecestat In Early Alzheimer’s Disease

Eisai Co., Ltd. (Headquarters: Tokyo, CEO: Haruo Naito, “Eisai”) as well as Biogen Inc. today reported the choice to discontinue Phase III clinical trials (MISSION AD1, AD2) on oral research BACE (beta-amyloid cleaving enzyme) elenbecestat inhibitor (development code: E2609) in patients with early Alzheimer’s disease (AD). The choice is based on the outcomes of a Data Safety Monitoring Board (DSMB) security review, which suggested that these studies be discontinued owing to an unfavorable risk-benefit ratio. Detailed information will be provided at future medical conferences for this research.

Investigators are notified of the choice and will contact their research respondents to stop the research treatment. Chief Clinical Officer, Dr. Lynn Kramer, of Neurology Business Group, Eisai Co., Ltd., told that they would like to honor the patients, relatives and medical experts who took part in the MISSION AD research.

The elenbecestat Phase III clinical trial program (MISSION AD) consisted of two identical protocol-based worldwide Phase III clinical trials, MISSION AD1 (Study 301) and MISSION AD2 (Study 302). All the studies were Phase III multicenter, double-blind, placebo-controlled, parallel-group clinical studies meant to assess the effectiveness and elenbecestat’s safety for treatment in a total of approximately 2,100 patients with cognitive impairment (MCI) or mild AD (collectively known as early AD) with confirmed amyloid pathology in the brain. During the 24-month therapy period, patients were randomized to either receive 50 mg of elenbecestat or placebo daily, with the main endpoint being the Clinical Dementia Rating Sum of Boxes (CDR-SB).

The long-term extension of elenbecestat’s Phase II clinical trial (Study 202) will also be discontinued as part of this choice. This determination does not affect the BAN2401 monoclonal antigen anti-amyloid beta (Aβ) program and the BAN2401 Phase III Clarity AD trial will remain.