Eisai And Biogen Present Real‑World LEADER Study Data At AAIC Showing Nearly 83% Of Early Alzheimer’s Patients Remained Stable Or Improved On LEQEMBI Therapy Over ~17 Months, With Consistent Results Across Diverse Groups.

Eisai Co., Ltd. and Biogen Inc. (NASDAQ:BIIB) announced today that results from the real-world Lecanemab in Early Alzheimer's Disease (LEADER) Study show that nearly 83% of early Alzheimer’s disease (AD) patients enrolled in the study remained stable (75.9%) or improved (6.6%) while receiving LEQEMBI® therapy over an average of 17 months. The results were consistent across sex, race, ethnicity and APOE genotype. The data was presented during the "Developing Topics Session #3-33-DEV-A: Lecanemab Three Years Post-Approval: A Comprehensive Multicenter, Real-World, Retrospective Study (LEADER) in Diverse US Clinical Settings" at the Alzheimer’s Association International Conference® (AAIC®) 2026 in London and online.

AD is a chronic, progressive disease that requires ongoing treatment. LEQEMBI targets the underlying pathology of the disease and works in two ways throughout treatment - by removing insoluble (plaque) and soluble amyloid beta (protofibrils), helping to slow cognitive decline and loss of daily functioning. Data show continued treatment with LEQEMBI may be able to help keep patients in early AD for longer. Early AD includes mild cognitive impairment (MCI) due to AD and mild AD dementia.