Characteristics of infusion-related reactions to lecanemab in early Alzheimer’s disease: A multicenter real-world study in Northwestern China

• Lower incidence, mild severity, and delayed onset characterize lecanemab‑associated IRRs in the Northwestern Chinese cohort. • The IRR incidence was highest at the first lecanemab infusion and decreased significantly thereafter. • Hypertension and white matter hyperintensity burden (higher Fazekas scores) are independent risk factors of IRRs. Infusion-related reactions (IRRs) represent the most common adverse events associated with lecanemab. However, real-world data on IRR characteristics and risk factors in Asian populations, particularly Chinese, remain scarce. In a multicenter prospective registry, 139 patients with early Alzheimer’s disease (AD) receiving lecanemab were included. IRRs were physician-confirmed. Multivariable logistic regression identified independent predictors. The cumulative IRR incidence was 12.36 %, highest at the first infusion (17.3 %) and decreased significantly thereafter ( P < 0.001). Fever (54.2 %) and dizziness (16.7 %) were the most common symptoms. 45.8 % of IRRs occurred 2–24 hours after infusion. All IRRs were mild (Grade 1) and self-limited. Hypertension (OR = 5.017, P = 0.007) and higher Fazekas score (OR = 2.734, P = 0.017) were independently associated with IRR. In this Chinese real‑world cohort, lecanemab‑associated IRRs were less frequent, mild, and delayed. Hypertension and white‑matter hyperintensity severity emerged as key risk factors, underscoring the potential role of cerebrovascular health in IRR susceptibility.