Application of Meta-analysis to Evaluate Relationships Among ARIA-E Rate, Amyloid Reduction Rate, and Clinical Cognitive Response in Amyloid Therapeutic Clinical Trials for Early Alzheimer’s Disease

Background Removal of the extracellular Aβ plaques in the brain is one of the mechanisms to treat Alzheimer’s disease (AD). Separate clinical trials for several therapeutic compounds that target amyloid plaque reduction have shown noteworthy correlations among plaque removal, the Amyloid-Related Imaging Abnormalities (ARIA) rate, and clinical efficacy of the treatment. The relationships among therapeutic dose levels, the rate of amyloid removal, and the clinical efficacy deserve further investigation across therapeutic agents, particularly for clinical trials to provide insights for strategies to develop amyloid therapies in Alzheimer’s disease. Methods Published data summaries from clinical trials with amyloid therapies of aducanumab, donanemab, lecanemab, and gantenerumab are evaluated with meta-analyses. Linear mixed models for repeated measurements for visits and random study effects are applied to analyze amyloid centiloid value reduction from baseline and clinical cognition change from baseline for treatment groups according to doses and compounds for the clinical trials. Logistic regression analysis is applied to evaluate the relationship between the amyloid removal rate and the ARIA-Edema (ARIA-E) rate across different dose groups and clinical trials. Results The extent of amyloid removal varies among therapeutic agents and their dose levels. Across treatment groups and clinical trials, amyloid centiloid value reductions at Weeks 26 and 52 are strongly correlated with both ARIA-E rate over 78 weeks and the clinical efficacy response in the Clinical Dementia-Rating Scale Sum of Boxes (CDR-SB) score change from baseline at Week 78; and the Spearman rank correlations for amyloid reduction at Week 52 are stronger as − 0.79 with the ARIA-E rate over 78 weeks and 0.73 with the Week 78 CDR-SB score change from baseline. Conclusion Aβ plaques removal in the brain due to amyloid therapy is strongly correlated with a better clinical response in patients with early Alzheimer’s disease and a higher ARIA-E rate for the treatment groups and clinical trials in this meta-analysis. These relationships suggest that the balance between the clinical efficacy response and safety in ARIA-E rate is relevant for the choice of doses for amyloid therapies in confirmatory clinical trials.