Eisai and Biogen report results of Phase IIb study of lecanemab in early AD


On 20 April, Biogen and Eisai announced the recent publication describing the results of the Study 201, a Phase IIb proof-of-concept study designed to evaluate the safety and efficacy of the anti-amyloid protofibril antibody lecanemab (BAN2401) in people with early Alzheimer's disease (AD). These findings were published in the journal Alzheimer's Research & Therapy.

The Study 201 was an 18- month multi-center, double-blind, placebo-controlled and parallel-group Phase IIb study of lecanemab in people with mild cognitive impairment (MCI) due to AD or mild AD dementia. Sponsored by Eisai, the study enrolled 854 participants from US, Europe and Asia, aged between 50 and 90, 609 of whom were assigned to receive lecanemab.

Results showed that the study did not meet the 12-month primary endpoint, which was a change from baseline in the Alzheimer's Disease Composite Score (ADCOMS) at 12 months. ADCOMS consists of several items including the mini mental state examination (MMSE), the clinical dementia rating- sum of boxes (CDR-SB) and the AD assessment scale-cognitive subscale (ADAS-Cog). Results from prespecified key secondary endpoint analyses demonstrated that lecanemab reduced brain amyloid and showed a consistent reduction of clinical decline across several clinical and biomarker endpoints at 18 months. In addition, lecanemab was generally well-tolerated with the key adverse event being amyloid-related imaging abnormalities-edema/effusion (ARIA-E) with an incidence rate of less than 10% at the highest doses for the overall population.

Currently, lecanemab is being studied in a Phase III clinical study in symptomatic early AD, named Clarity AD. This study completed enrolment in March with 1,795 symptomatic participants who received either lecanemab or placebo during 18 months. The 18-month results are expected to be available in September 2022.