Real-world data on lecanemab estimate amyloid-related imaging abnormalities (ARIA) at 15.1%, with higher rates in APOE ε4 homozygotes and in patients with baseline microhemorrhages. A meta-analysis of 37 studies found insufficient controlled evidence to confirm cognitive efficacy, while reinforcing the need to refine patient selection and monitoring protocols as use expands beyond trial populations. For the market, the balance of measurable imaging risk signals and still-uncertain functional outcomes is likely to influence payer policies, real-world adoption pathways, and trial designs aiming to reduce ARIA while preserving efficacy.