Today, Eisai Co. Ltd. presented new findings on lecanemab-irmb (branded as LEQEMBI® in the U.S.) at the Alzheimer’s Association International Conference (AAIC) 2024 in Philadelphia and online. This dual-acting anti-amyloid beta (Aβ) protofibril antibody is designed for early Alzheimer’s disease (AD) treatment. LEQEMBI® is unique in its ability to support neuronal function by targeting toxic protofibrils, which can cause neuronal damage even after plaque removal.
The new data reveals that three years of continuous lecanemab treatment led to a -0.95 reduction in cognitive decline on the Clinical Dementia Rating-Sum of Boxes (CDR-SB) scale compared to expected decline rates from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) group. This shows a continued meaningful benefit for early AD patients.
The Clarity AD Phase 3 study, which involved 1,795 participants, demonstrated that lecanemab significantly reduced cognitive decline compared to placebo. After the core 18-month study, 95% of participants chose to continue in the open-label extension. In the Clarity AD study, lecanemab’s impact persisted over three years, reducing cognitive decline significantly.
Regarding safety, no new safety concerns emerged with three years of lecanemab treatment. Most Amyloid-related imaging abnormalities (ARIA) occurred within the first six months, with rates comparable to placebo thereafter. ARIA did not affect cognitive function or accelerate long-term progression.
In the optional tau PET substudy, 59% of patients with early AD who started treatment with low tau levels showed improvement or no decline after three years. This suggests early initiation of lecanemab may positively impact disease progression.
Additionally, the Study 201 Phase 2b trial showed that AD progression continues even after plaque clearance when treatment is stopped, reverting to the placebo rate of decline. Continuous treatment with lecanemab maintains improvement in key biomarkers like Aβ42/40, pTau181, and GFAP, highlighting its ongoing efficacy.
Lecanemab’s dual action targets both toxic protofibrils and amyloid plaques, helping to slow tau spread and providing long-term benefits for AD patients. The continued benefits suggest that maintaining treatment with lecanemab is crucial for ongoing disease management.
For more details, presentation slides from AAIC 2024 will be available on the Eisai Co. Ltd. Investor Page by 7:00 p.m. EDT on July 30th.
Important Safety Information:
LEQEMBI® may cause ARIA, including ARIA with edema (ARIA-E) and hemosiderin deposition (ARIA-H). ARIA generally occurs early in treatment and may be asymptomatic, though serious events can occur. The incidence of ARIA varies among patients, particularly among those with ApoE ε4 homozygote status. Full prescribing information, including warnings and contraindications, is available.
