Eisai releases new 36-month efficacy data on Leqembi

Japanese drugmaker Eisai (TYO: 4523) and US biotech major Biogen (Nasdaq: BIIB) have presented new clinical data from a post-hoc sub-group analysis of the Clarity AD, open-label extension (OLE) study.

The data demonstrated that treatment with lecanemab in adult patients with early Alzheimer’s disease (AD) (mild cognitive impairment [MCI] or mild dementia due to AD, with confirmed amyloid pathology) who are apolipoprotein E ε4 (ApoE ε4) non-carriers or heterozygotes continued to accrue benefit over 36 months, relative to the Alzheimer’s Disease Neuroimaging Initiative (ADNI) cohort. The 36-month data was presented at Rencontres Francophones sur la Maladie d’Alzheimer et les Syndromes Apparentés (RFMASA) 2025 in Lausanne, Switzerland.

Clarity AD is a global Phase III placebo-controlled, double-blind, parallel-group, randomised study in 1,795 patients with early AD. Of the total number of patients randomized, 1,521 were ApoE ε4 non-carriers or heterozygotes. The primary endpoint was the change in the score of the global cognitive and functional scale, Clinical Dementia Rating - Sum of Boxes (CDR-SB).  Clarity AD includes an OLE phase for eligible patients to evaluate the long-term safety profile and tolerability of lecanemab, and whether the effects of the treatment are maintained over time.1,3