Therapeutic Advances in Targeting the Amyloid-β Pathway for Alzheimer's Disease

Alzheimer's disease (AD) is the most common cause of dementia, characterized by progressive cognitive decline and neuropathological hallmarks, including amyloid-β (Aβ) plaques, neurofibrillary tangles (NFTs), and neurodegeneration. Since the amyloid cascade hypothesis was proposed, Aβ has remained a central therapeutic target, with interventions aiming to reduce Aβ production, aggregation, or downstream toxicity. This review first outlines the historical development of the Aβ hypothesis and the two major APP processing pathways (α-cleavage and β-cleavage), highlighting the role of biomarkers in early diagnosis, patient stratification, and regulatory approval. We then summarize the development and clinical outcomes of anti-Aβ small-molecule drugs, including β-secretase inhibitors, γ-secretase modulators, Aβ aggregation inhibitors, receptor/synapse modulators, and metabolic or antioxidant modalities. We further review the progression of biologic therapies, with a particular focus on monoclonal antibodies, vaccines, and emerging gene-silencing strategies, such as small interfering RNA (siRNA) and antisense oligonucleotides. Finally, we discuss future perspectives, including next-generation biologics, multi-target approaches, optimized delivery platforms, and early-prevention strategies. Collectively, these efforts underscore both the challenges and opportunities in translating anti-Aβ therapies into meaningful clinical benefits for patients with AD.