Lecanemab Shows Sustained Benefit at 4 Years in Early Alzheimer Disease: Daily Dose

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On August 1, 2025, we reported on study findings presented at the 2025 Alzheimer’s Association International Conference (AAIC) that demonstrated the benefits of continuous treatment with lecanemab-irmb for the treatment of early Alzheimer disease (AD).

The study

Researchers presented 4-year data from the open-label extension (OLE) of the Clarity AD clinical trial, which randomized 1795 participants with early symptomatic AD to receive lecanemab or placebo biweekly for 18 months. Of those completing the core study, 95% entered the OLE, and 478 patients continued treatment for 4 years.

The findings

At 18 months, the treatment group showed a mean –0.45 point difference on the Clinical Dementia Rating–Sum of Boxes (CDR-SB) versus placebo (P = .00005). Over four years, the mean CDR-SB benefit compared with the Alzheimer’s Disease Neuroimaging Initiative (ADNI) natural history cohort increased to –1.75 points. When compared with the BioFINDER cohort, the mean benefit reached –2.17 points at four years.

An analysis of a tau PET substudy further indicated that 56% of patients with low baseline tau levels showed improvement from baseline on CDR-SB after four years of lecanemab treatment, and 69% showed no decline or improvement. On the ADAS-Cog14, 51% of patients demonstrated either stability or improvement; on the ADCS-MCI-ADL, 58% showed improvement and 64% remained stable or improved.

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