APOE and Alzheimer disease: This finding carries direct clinical implications: For patient populations who are APOE ε4 carriers or require rapid amyloid plaque clearance (e.g., rapidly progressive Alzheimer’s disease), clinicians should prioritize evaluating the short-term efficacy-risk balance of donanemab and consider increasing MRI monitoring frequency during pretreatment and early treatment phases (e.g., baseline and scans at months 3, 6, and 9) to dynamically manage ARIA events.