Biweekly Leqembi treatment for 3 years reduced cognitive decline by –0.95 on the Clinical Dementia Rating–Sum of Boxes scale, more than doubling the benefit observed at 18 months, according to a recent announcement.
The US Food and Drug Administration (FDA) approved a supplemental Biologics License Application (sBLA) for Leqembi (lecanemab-irmb), permitting a once-every-4-weeks intravenous (IV) maintenance dosing regimen for individuals with early Alzheimer’s disease (AD). This approval applies to patients who have completed the 18-month biweekly initiation phase of 10 mg/kg dosing. Leqembi is indicated for the treatment of mild cognitive impairment or mild dementia stages of AD in the United States.
Researchers from Eisai and BioArctic supported the sBLA with data from both the phase II core study and its long-term extension (LTE), as well as the phase III Clarity AD study and LTE. Data showed discontinuation of biweekly Leqembi led to the reaccumulation of brain amyloid, as well as plasma and cerebrospinal fluid biomarker reversals, and a clinical decline consistent with placebo rates. Data indicated that discontinuation of treatment led to a reversal of clinical and biomarker improvements, emphasizing the potential value of continued therapy. Modeling based on these datasets predicts that transitioning to a once-every-4-weeks maintenance regimen would preserve the clinical and biomarker improvements observed during the initiation phase.
Notably, 3 years of biweekly Leqembi treatment demonstrated a reduction in cognitive decline, as measured by the Clinical Dementia Rating–Sum of Boxes score, by –0.95 points relative to a matched natural history cohort, more than double the –0.45-point reduction relative to placebo observed at 18 months. These findings indicate that prolonged Leqembi administration provides clinically meaningful benefits for patients with early AD.
Leqembi’s mechanism of action involves rapid clearance of amyloid-beta (Aβ) plaques and the continuous removal of toxic Aβ protofibrils that contribute to neuronal damage and disease progression. The approval is supported by evidence linking sustained Aβ reduction with clinical and biomarker benefits in early AD.
Leqembi is approved in multiple regions, including the US, Japan, and China, with applications pending in 17 additional countries. Eisai and BioArctic also announced an FDA submission for a subcutaneous autoinjector of Leqembi, with a Prescription Drug User Fee Act action date set for August 31, 2025.
