MONDAY, Aug. 17, 2026 (HealthDay News) -- Nearly 1 in 4 patients treated with lecanemab for mild cognitive impairment or mild Alzheimer disease (AD) with confirmed amyloid pathology develop amyloid-related imaging abnormality (ARIA), according to a study published online Aug. 7 in Neurology Open Access.Andy J. Liu, M.D., from the Duke University School of Medicine in Durham, North Carolina, and colleagues conducted a retrospective, single-site observational study in patients with mild cognitive impairment or mild AD with confirmed amyloid pathology treated with lecanemab. The primary aim was to assess ARIA incidence and serious adverse events.A total of 230 patients were followed for a mean of 396 days; 49 patients (21 percent) discontinued treatment. The researchers found that 56 patients (24.3 percent) had ARIA. The peak incidence rate of ARIA with edema (ARIA-E) and ARIA with microhemorrhages was generally at ~10 weeks, with a smaller ARIA-E peak at ~25 weeks. Seventy-two patients (31.3 percent) had clinically significant adverse events, including five deaths, two related to ARIA. There was no difference in 12-month cognitive changes by ARIA status, although a significant decline of 0.107 units per month was seen in the Montreal Cognitive Assessment score. APOE ε4 carriers and men had elevated ARIA-E risk (odds ratio, 4.81 for two copies; odds ratio, 2.40). High specificity (>90 percent) but low sensitivity (<25 percent) was seen for baseline ptau-181/amyloid beta 42, APOE ε4, and Fazekas scores for ARIA. Fewer ARIA events were seen with initiation of treatment earlier in the disease course, especially among APOE ε4 noncarriers and those with lower baseline amyloid burden."This is about buying time in a disease that takes it away," Liu said in a statement. "And our real-world experience shows that with careful risk-benefit assessments, time can be gained by many patients."Several authors disclosed ties to the pharmaceutical industry.Abstract/Full TextEditorial.Sign up for our weekly HealthDay newsletter