ARIA in patients treated with lecanemab (BAN2401) in a phase 2 study in early Alzheimer's disease

INTRODUCTION: Lecanemab is a humanized immunoglobulin G1 (IgG1) monoclonal antibody that preferentially targets soluble aggregated Aβ species (protofibrils) with activity at amyloid plaques. Amyloid-related imaging abnormalities (ARIA) profiles appear to differ for various anti-amyloid antibodies. Here, we present ARIA data from a large phase 2 lecanemab trial (Study 201) in early Alzheimer's disease. METHODS: Study 201 trial was double-blind, placebo-controlled (core) with an open-label extension (OLE). Observed ARIA events were summarized and modeled via Kaplan-Meier graphs. An exposure response model was developed. RESULTS: In the phase 2 core and OLE, there was a low incidence of ARIA-E (<10%), with <3% symptomatic cases. ARIA-E was generally asymptomatic, mild-to-moderate in severity, and occurred early (<3 months). ARIA-E was correlated with maximum lecanemab serum concentration and incidence was higher in apolipoprotein E4 (ApoE4) homozygous carriers. ARIA-H and ARIA-E occurred with similar frequency in core and OLE. DISCUSSION: Lecanemab can be administered without titration with modest incidence of ARIA.