Temporal Evolution of ARIA After Lecanemab Interruption: A Longitudinal Volumetric MRI Study

Area of Science:

• Neurology
• Radiology
• Pharmacology

Background:

• Lecanemab treatment for Alzheimer's disease can cause amyloid-related imaging abnormalities (ARIA).
• The resolution patterns of ARIA-E (edema/effusion) and ARIA-H (hemorrhages/siderosis) after lecanemab interruption require further characterization.
• APOE genotype may influence ARIA development and resolution.

Purpose of the Study:

• To quantify the volumetric changes of ARIA-E after lecanemab interruption.
• To assess the incidence and progression of ARIA-H following ARIA-E detection.
• To evaluate the impact of APOE genotype on ARIA evolution.

Main Methods:

• Retrospective analysis of 24 patients who developed ARIA-E during lecanemab therapy.
• Longitudinal brain MRI scans (3D FLAIR, SWI/GRE) were used to measure ARIA-E volume and assess ARIA-H.
• Patients were stratified by APOE genotype (ε4 non-carriers, ε3/ε4 heterozygotes, ε4/ε4 homozygotes).

Main Results:

• ARIA-E volume significantly decreased, with a 92% mean reduction by the second follow-up (approx. 75 days).
• Complete radiographic resolution of ARIA-E was observed in 75% of patients within 2-3 months.
• ARIA-H developed in 83.3% of patients, including microhemorrhages (67%) and superficial siderosis (29%).

Conclusions:

• ARIA-E demonstrates substantial early reversibility after lecanemab cessation.
• The high incidence of ARIA-H necessitates ongoing MRI monitoring post-ARIA-E diagnosis.
• Understanding ARIA evolution is crucial for managing patients on lecanemab therapy.