APOE and Alzheimer disease: Phase III CLARITY‐AD (n = 1795): 18‐month CDR‐SB difference −0.45 (1.21 vs. 1.66); secondary endpoints (ADAS‐Cog14/ADCOMS/ADCS‐MCI‐ADL) also improved; ARIA‐E ≈ 12.6%, infusion‐related reactions 26.4%77; AUR recommends APOE ε4 genotyping and strict MRI monitoring.33