Leqembi Slows Alzheimer's Progression 34% Over Four Years

New data presented at the Alzheimer's Association International Conference in 2025 confirm that Eisai and Biogen's Alzheimer's drug Leqembi continues to slow cognitive decline effectively over extended treatment periods, including four years, with no new safety concerns. Real-world studies in the U.S. show high treatment continuation rates (87.4%) and clinical stability or improvement in 83.6% of patients, alongside a favorable safety profile with low incidence of amyloid-related imaging abnormalities (ARIA). Leqembi targets toxic protofibrils and amyloid plaques, key contributors to Alzheimer's disease progression, and has demonstrated a 34% slowing of cognitive decline compared to untreated patients after four years. Patients initiating treatment in the earliest stages of Alzheimer's benefit most, with many showing sustained clinical improvements and longer retention in early disease stages. The injectable version of Leqembi is currently under FDA review, with a decision expected by August 31, 2025, offering potential convenience benefits. Overall, these findings underscore Leqembi's therapeutic potential and support ongoing research in pre-symptomatic Alzheimer's populations.