A Narrative Review of Amyloid-β Monoclonal Antibodies for Alzheimer Disease: How Amyloid Species Engagement May Affect Clinical Outcomes.

BACKGROUND

Alzheimer's disease (AD) is a leading cause of death worldwide, with growing prevalence as life expectancy increases. An important neurological hallmark of AD is the deposition of extracellular neuritic amyloid-β (Aβ) plaques that can disrupt synaptic transmission and cause neuronal death. More recent studies suggest that targeting Aβ species can slow the progression of cognitive decline in AD.

REVIEW SUMMARY: This narrative review examines the efficacy of monoclonal antibodies targeting the amyloid-β (Aβ) protein in the treatment of AD. It discusses the mechanisms by which these antibodies aim to mitigate amyloid pathology and explores their clinical outcomes in various trials. The review highlights the importance of amyloid plaque reduction to less than 25 Centiloids observed through amyloid positron emission tomography (PET) scans as a predictor of slowing cognitive decline. The findings suggest that targeting insoluble amyloid plaques is crucial for achieving clinical benefits in AD treatment. This review also discusses the phenomenon of amyloid-related imaging abnormalities (ARIA) that may be associated with monoclonal antibody therapy.

CONCLUSION

Monoclonal antibodies that target Aβ monomers, soluble oligomers and protofibrils, and insoluble fibrils/plaques were developed, and not all have provided clinical benefit. Emerging evidence suggests that it is important to reduce amyloid plaque burden to less than 25 Centiloids, consistent with a visually negative amyloid PET scan, in order to slow cognitive decline in early symptomatic AD.