Dementia Drug 'Lecanemab' Shows "Safety Demonstrated" in Real-World Clinical Use Among Korean Patients [Health Check]

[Financial News] A real-world clinical analysis of 127 Korean patients with Alzheimer's disease found that 21.3% experienced adverse reactions after receiving Lecanemab, although most cases were mild or asymptomatic.
The study was conducted and published by a team from the Departments of Neurology, Radiology, and Nuclear Medicine at Korea University Guro Hospital. The team included Professor Kang Sung-hoon, director of the Alzheimer's Prevention Center; resident physician Shin Jae-min; Professor Suh Sang Il; and Professor Eo Jae Seon. They analyzed the real-world clinical experience of treating Korean patients with Lecanemab, an Alzheimer's disease treatment whose brand name is Leqembi. Although Lecanemab's efficacy and safety have been established through clinical trials, relatively little data has been available on treatment safety and the pattern of adverse reactions among Asian patients in routine clinical settings.
The research team analyzed infusion-related reactions, amyloid-related imaging abnormalities (ARIA), ARIA risk factors, and early changes in cognitive function among 127 patients who began Lecanemab treatment at the Alzheimer's Prevention Center at Korea University Guro Hospital between December 2024 and October 2025.
Infusion-related reactions, including fever, generalized weakness, and headaches, occurred in 21.3% of all patients. Most appeared during or immediately after the first dose. Among the 102 patients who underwent follow-up MRI scans after treatment, ARIA was identified in 8.8%; in most cases, it was radiologically mild or clinically asymptomatic.

Up to six months after treatment began, scores on the Mini-Mental State Examination (MMSE), used to assess changes in cognitive function, remained generally stable. The risk of ARIA was also found to be higher in patients with numerous cerebral microbleeds or severe white-matter degeneration before treatment, underscoring the importance of assessing each patient's risk before treatment and conducting regular MRI monitoring.
After publishing the paper, the research team continued follow-up observations and expanded the number of patients receiving Lecanemab in routine clinical practice to 233. In the expanded patient group, infusion-related reactions were observed in 25.3% of patients, ARIA-E, involving cerebral edema or effusion, in 4.0%, and ARIA-H, involving cerebral microbleeds and other hemorrhagic abnormalities, in 8.5%. Overall, the safety profile was similar to the initial findings reported in the paper. In particular, no new safety signals were observed after clinical experience accumulated and the treatment population expanded. Most adverse reactions were mild or asymptomatic and manageable.
Professor Kang Sung-hoon said, "The significance of this study lies in the fact that it systematically analyzed the treatment outcomes and safety of patients who received Lecanemab in an actual domestic clinical setting rather than in a clinical trial. Even in routine clinical practice, most infusion-related reactions and cases of ARIA were mild or asymptomatic and manageable. We expect treatment can be administered more safely if risk is assessed using brain MRI before treatment and regular MRI monitoring is conducted during treatment."
The study was conducted based on K-LEARN, a research cohort that uses standardized methods to conduct long-term follow-up of the real-world clinical outcomes of patients receiving Lecanemab, as well as their blood biomarkers, MRI findings, amyloid PET scans, and changes in cognitive function. The paper, titled "Real-World Clinical Application of Lecanemab in Korean Patients: Analysis of Safety, ARIA Risk, and Early Treatment Patterns," was recently published in the Alzheimer's Association's international journal Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring (DADM).
 



[email protected] Jung Myung-jin, medical correspondent Reporter