FDA Approval and Dosing Regimen - The FDA approved Eisai's Supplemental Biologics License Application (sBLA) for Leqembi, allowing a once every four weeks intravenous (IV) maintenance dosing for patients with mild cognitive impairment (MCI) or mild dementia due to Alzheimer's disease [1] - Patients who completed the 18-month biweekly initiation phase can transition to the 10 mg/kg once every four weeks dosing regimen [1] - The approval is based on modeling data from Phase 2 and Clarity AD studies, predicting that the new dosing regimen will maintain clinical and biomarker benefits [3] Clinical Benefits and Mechanism of Action - Leqembi reduces cognitive decline by -0.95 on the CDR-SB scale compared to a matched natural history cohort, more than double the placebo effect at 18 months (-0.45) [2] - The drug works by rapidly clearing amyloid-beta (Aβ) plaque and continuously clearing highly toxic protofibrils, addressing the progressive nature of Alzheimer's disease [2] - Discontinuation of treatment leads to reaccumulation of brain amyloid and reversion to placebo rates of clinical decline, emphasizing the importance of continuous administration [2] Global Market Approvals and Submissions - Leqembi is approved in the US, Japan, China, Great Britain, and several other markets [4] - The European Medicines Agency's Committee for Medicinal Products for Human Use (CHMP) issued a positive opinion recommending approval in November 2024 [4] - Eisai has submitted applications for approval in 17 countries and regions, including the European Union [4][10] - The FDA accepted a Supplemental Biologics License Application (BLA) for a subcutaneous autoinjector formulation with a PDUFA action date of August 31, 2025 [4][10] Collaboration and Commercialization - Leqembi is the result of a long-standing collaboration between BioArctic and Eisai, with BioArctic having the right to jointly commercialize the drug in the Nordic region pending European approval [5][13] - Eisai is responsible for clinical development, regulatory applications, and global commercialization, while BioArctic is entitled to payments for regulatory approvals, sales milestones, and royalties on global sales [5][13] Ongoing Clinical Studies - Eisai's Phase 3 AHEAD 3-45 study, investigating lecanemab in preclinical Alzheimer's disease, was fully recruited in October 2024 and is ongoing [11] - The Tau NexGen clinical study for Dominantly Inherited Alzheimer's Disease (DIAD) includes lecanemab as the backbone anti-amyloid therapy and is ongoing since January 2022 [11] About Leqembi (Lecanemab) - Lecanemab is a humanized immunoglobulin gamma 1 (IgG1) monoclonal antibody targeting aggregated soluble and insoluble forms of amyloid-beta (Aβ) [7] - It is approved for treating mild cognitive impairment (MCI) and mild Alzheimer's dementia in multiple markets, with approvals based on Phase 3 data from the Clarity AD trial [8][9] - Common adverse events include infusion reactions, ARIA-H, ARIA-E, headache, and fall [9]
FDA approves IV maintenance dosing of Leqembi® (lecanemab-irmb) for the treatment of early Alzheimer's Disease in the US