Amyloid-Related Imaging Abnormalities Dominate Aducanumab’s Complete Post-Marketing Record: A Comparative Pharmacovigilance Analysis

This is a pharmacovigilance analysis of the complete adverse event record for aducanumab. Aducanumab (brand name Aduhelm), a monoclonal antibody, reduces the aggregation of beta-amyloid plaque, associated with symptoms of Alzheimer’s disease, the most common dementia impacting millions annually. However, aducanumab has ambiguous effects due to clinically inconclusive studies. In 2024, Aduhelm was commercially and developmentally discontinued by Biogen for excessive costs for treatment, low adoption, and controversy over its efficacy. Reports are from the Food and Drug Administration Adverse Event Monitoring System Public Dashboard for aducanumab. The procedure was replicated for successors lecanemab and donanemab. Aducanumab received 486 cases between 2016 and 2024, having 266 (54.7%) serious cases, including 29 deaths (6.0%). Five amyloid-related imaging abnormality (ARIA) terms accounted for 253 reaction entries in 181 unique cases (37.2% of all cases). Sex distribution of reports was about even (48.1% female of all cases; 52.8% of cases with known sex; 53.8% female of known sex among ARIA cases), contrasting the female-predominant Alzheimer’s population. ARIA cases were reported by healthcare professionals significantly more often than other cases (69.6% versus 48.2%). Relative to lecanemab (25.7%) and donanemab (34.0%), aducanumab had the largest share of ARIA reports (37.2%), and female ARIA cases for both successors (~65%) exceeded that seen for aducanumab. Four hypotheses were proposed: that ARIA terms would dominate the profile, that women would represent a majority of reports, that ARIA would be disproportionately healthcare-reported, and that reporting volume would track the product life cycle.