Serial amyloid PET demonstrates marked reduction in amyloid burden following donanemab treatment: a real-world cohort study

PURPOSE: To evaluate changes in amyloid burden on serial amyloid PET before and after donanemab treatment in a real-world clinical cohort. METHODS: This retrospective study included 20 consecutive patients who underwent serial amyloid PET before and after donanemab treatment. Quantitative analysis was performed using Centiloid values and tracer-specific standardized uptake value ratios (SUVr). Visual assessment was also performed to determine amyloid-positive or amyloid-negative status before and after treatment. RESULTS: Centiloid values significantly decreased from 52.3 ± 23.4 at baseline to - 5.6 ± 16.5 at follow-up, with a mean change of - 58.0 (p < 0.001). All patients showed a reduction in Centiloid values. In the flutemetamol group (n = 12), pons-referenced SUVr significantly decreased, while in the florbetapir group (n = 8), cerebellar-referenced SUVr also showed significant reductions (both p < 0.001). On visual assessment, 17 of 20 patients (85%) converted from amyloid-positive to amyloid-negative status after treatment. CONCLUSION: Serial amyloid PET demonstrated a substantial reduction in amyloid burden following donanemab treatment in this real-world cohort. Quantitative amyloid PET, particularly using Centiloid scaling, may be a useful tool for monitoring treatment response in clinical practice.