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.