Yesterday, Eisai and Biogen announced that Japanese regulators had approved their anti-amyloid drug, lecanemab, for the treatment of mild cognitive impairment or mild dementia due to Alzheimer’s disease. Lecanemab, which is marketed under the Leqembi® brand name, was approved by the US Food and Drug Administration in July. The drug was granted priority review status by the Japanese Ministry of Health, Labour and Welfare (MHLW) in January, with a review panel greenlighting its approval in August. Lecanemab is one of the first approved disease-modifying therapies for Alzheimer’s disease (AD). As a monoclonal antibody therapy, lecanemab targets and clears amyloid plaques that build up in the brain during the development of AD. Approval by Japanese regulators was based on the results of CLARITY-AD, a Phase 3, confirmatory trial which enrolled 1,795 participants who received either lecanemab (10mg/kg) or a placebo biweekly via intravenous infusion.
This study met all its primary and secondary endpoints, demonstrating a 27% reduction in clinical decline after 18 months of lecanemab treatment on the global cognitive and functional scale, CDR-SB. In their press release, Eisai and Biogen highlighted results on a caregiver-reported assessment scale (the ADCS MCI-ADL) which showed a 37% benefit compared to placebo. The most common side-effects caused by lecanemab included amyloid-related imaging abnormalities (termed ARIA), which are linked to swelling or small bleeds in the brain. While most cases of ARIA in the CLARITY-AD trial were mild or asymptomatic, 0.7% caused seizures and other severe symptoms. In accordance with an approval condition imposed by the MHLW, the companies will conduct a post-marketing surveillance study in all patients who receive lecanemab, until data from a certain number of patients are accumulated following market launch of the drug. Lecanemab is currently under review at the European Medicines Agency, with an outcome expected later this year or in early 2024. Read the full press release, here: https://www.eisai.com/news/2023/news202359.html