Background

Lecanemab is the first drug approved by FDA for the treatment of early Alzheimer’s disease (AD) with confirmed brain amyloid pathology. However, the long-term efficacy and safety of Lecanemab in China had not been reported.

Methods

This is a multicenter case registry study conducted at 13 hospitals in Northwest China. All AD patients treated with Lecanemab were enrolled. The efficacy of Lecanemab was evaluated using Clinical Dementia Rating-Sum of Boxes (CDR-SB), Alzheimer’s Disease Assessment Scale (ADAS-cog), Alzheimer’s Disease Cooperative Study-Activities of Daily Living Scale (ADCS-ADL), and Minimal-Mental State Examination (MMSE) every 3 months. Amyloid-related imaging abnormalities (ARIA) were monitored via MRI-T2-FLAIR and MRI-SWI sequences. Blood samples were collected to evaluate changes in plasma biomarkers (including Aβ42, Aβ40, Aβ42/40, p-tau181, p-tau217, GFAP, and NfL).

Results

189 participants received Lecanemab treatment until April 1, 2026, all of whom were confirmed Aβ-positive by CSF or PET scans. The mean age was 67.1 years (range 37-88), with 123 (65.1%) female participants. The mean years of education was 11.9 years. Among the participants, 20 (10.6%) were homozygous for the ApoE ε4 allele, and 89 (47.1%) were heterozygous. At baseline, the CDR-SB score was 4.3±2.4, the MMSE score was 18.7±6.2, the ADAS-cog score was 19.0±10.7, and the ADCS-ADL score was 56.6±17.8.

There were 94 participants completed the 3-month follow-up, 58 participants completed the 6-month follow-up, 33 participants completed the 9-month follow-up, and 21 participants completed the 12-month follow-up. The longest follow-up duration was 80 weeks.

The change in CDR-SB at 6 months compare to baseline was 0.36 (95% CI -0.19 to 0.91, P=0.193), for the MMSE score was 0.36 (95% CI -0.50 to 1.22, P=0.400), for the ADAS-cog score was 0.77 (95% CI -0.86 to 2.41, P=0.343), and for ADCS-ADL -4.35 (95% CI -6.88 to -1.81, P=0.002).

The plasma Aβ_42/40 ratio decreased by 0.004 (95% CI 0.001 to 0.007, P=0.011), plasma Aβ40 increased by 12.66 (95% CI 3.02 to 22.30, P=0.012), p-Tau 181 decreased by 1.21 (95% CI 0.65 to 1.77, P<0.001), and GFAP decreased by 42.44 (95% CI 24.51 to 60.37, P<0.001) at 6 months compared to baseline, whereas other plasma biomarkers showed no significant changes.

Only 4 asymptomatic ARIA (2. 56%, 1 ARIA-E and 3 ARIA-H) have been reported. Approximately 20% of patients reported treatment-related adverse events, primarily infusion-related reactions at the first infusion, such as fever and chills, which typically occurred within 24 hours post-infusion and were alleviated with symptomatic treatment.

Conclusion

This real-world study suggests that Lecanemab is well-tolerated in clinical use in Northwest China, with manageable adverse effects, and no severe adverse events have been reported to date. The neuropsychological scales remain stable during the 6-month follow-up, with males having more efficacy. Plasma biomarkers showed significant improvement after treatment. A long-term follow-up and a large sample are needed.