Biogen(US:BIIB) Globenewswire·2025-12-03 23:10Core Insights - Long-term treatment with LEQEMBI may delay the progression of Alzheimer's disease from Mild Cognitive Impairment (MCI) to moderate Alzheimer's by up to 8.3 years in low-amyloid patients who start treatment early [1][5][4] Group 1: Treatment Efficacy - Continued LEQEMBI treatment shows significant time savings in disease progression, with untreated patients progressing from MCI to mild AD in 7.2 years, while those on LEQEMBI take 9.7 years, indicating a time savings of 2.5 years [5] - In the low-amyloid group, the time to progression from MCI to mild AD was 13.2 years with LEQEMBI treatment, suggesting a time savings of 6.0 years [5] - The untreated group took 10.1 years to progress from MCI to moderate AD, while LEQEMBI treatment extended this to 13.6 years, indicating a time savings of 3.5 years [5] - For low-amyloid patients, the time to progression to moderate AD was extended to 18.4 years with LEQEMBI, suggesting a time savings of 8.3 years [5] Group 2: Safety and Administration - The subcutaneous formulation of lecanemab (LEQEMBI) has shown bioequivalence to intravenous dosing, with a 104% exposure ratio [6][7] - Safety evaluations indicated a low incidence of systemic infusion reactions (0% for 500 mg SC) compared to the IV group (26.4%) [8][9] - The incidence of amyloid-related imaging abnormalities (ARIA) was comparable between subcutaneous and intravenous administration, with ARIA-E observed in 13% of LEQEMBI patients [16][7] Group 3: Regulatory and Market Position - LEQEMBI has been approved in 51 countries, including Japan and the U.S., and is under regulatory review in 9 additional countries [34] - The U.S. FDA approved the subcutaneous maintenance dosing of LEQEMBI in August 2025, with a supplemental Biologics License Application for initiation treatment completed in November 2025 [1][34] - Eisai and Biogen are co-commercializing LEQEMBI, with Eisai leading the development and regulatory submissions globally [9][37]