Real-world safety study of Lecanemab in Japanese AD patients

This real-world observational study evaluated the safety profile of Lecanemab in Japanese patients with Alzheimer's disease in routine clinical practice. The study was conducted at a single center in Japan with a follow-up period of up to 18 months. A total of 120 Japanese patients who received Lecanemab treatment between December 2023 and November 2025 were included, with the requirement that they underwent at least one brain MRI before the fifth infusion. The primary focus was on monitoring safety outcomes including amyloid-related imaging abnormalities (ARIA), infusion-related reactions (IRRs), and treatment discontinuation rates. The study population had a mean age of 74.2 years, was predominantly female (74%), and most patients (88%) had a baseline CDR global score of 0.5, indicating mild cognitive impairment. During the follow-up period, 81 patients completed the 12-month assessment. The study found that ARIA occurred in 20% of patients, with ARIA-E occurring in 4% and isolated ARIA-H in 16%. Importantly, no patients experienced symptomatic ARIA. All patients with ARIA-E who had APOE data available were ε4 carriers.

This real-world observational study evaluated the safety profile of Lecanemab in Japanese patients with Alzheimer's disease in routine clinical practice. The study was conducted at a single center in Japan with a follow-up period of up to 18 months. A total of 120 Japanese patients who received Lecanemab treatment between December 2023 and November 2025 were included, with the requirement that they underwent at least one brain MRI before the fifth infusion. The primary focus was on monitoring safety outcomes including amyloid-related imaging abnormalities (ARIA), infusion-related reactions (IRRs), and treatment discontinuation rates. The study population had a mean age of 74.2 years, was predominantly female (74%), and most patients (88%) had a baseline CDR global score of 0.5, indicating mild cognitive impairment. During the follow-up period, 81 patients completed the 12-month assessment. The study found that ARIA occurred in 20% of patients, with ARIA-E occurring in 4% and isolated ARIA-H in 16%. Importantly, no patients experienced symptomatic ARIA. All patients with ARIA-E who had APOE data available were ε4 carriers. Patients who developed ARIA had significantly lower baseline MMSE scores and showed non-significant trends toward higher plasma GFAP levels and higher deep white matter Fazekas scores. Infusion-related reactions occurred in 28% of patients, all classified as mild. Treatment discontinuation occurred in 16% of patients, primarily due to disease progression.