Amyloid-Related Imaging Abnormalities in Anti-amyloid Therapy: Clinical Implications of Kinetics for Safer Use and Risk Stratification.

Anti-amyloid monoclonal antibodies have emerged as disease-modifying therapies for Alzheimer's disease. However, their broader clinical adoption is limited by amyloid-related imaging abnormalities, a key safety concern. Traditionally viewed as an unavoidable and dose-dependent adverse effect, amyloid-related imaging abnormalities often lead to treatment interruption or the exclusion of high-risk patients from therapy. Emerging evidence now suggests that amyloid-related imaging abnormalities may instead reflect a transient modifiable cerebrovascular response, primarily influenced by the kinetics of amyloid clearance rather than the absolute magnitude of amyloid removal. Recent data from titration-based dosing strategies demonstrate that gradual amyloid mobilization can significantly reduce the incidence of amyloid-related imaging abnormalities without compromising amyloid positron emission tomography responses or downstream biomarkers. This kinetic perspective may support a more nuanced re-evaluation of patient groups previously deemed unsuitable for therapy, including APOE ε4 carriers, individuals with cerebral microbleeds, and patients on antithrombotic treatment. In this Current Opinion, we propose a pragmatic clinical framework that integrates amyloid clearance kinetics, magnetic resonance imaging-based risk stratification, and individualized protocols for treatment interruption and re-challenge. By reframing amyloid-related imaging abnormalities as a modifiable clinical decision-making challenge rather than an inherent toxicity, anti-amyloid therapies may be optimized for safer use; however, whether such approaches can enable broader and more inclusive treatment strategies remains to be established in prospective studies, particularly in high-risk populations.