Oncology drug repurposing as a blueprint for Alzheimer's therapy.

Alzheimer's disease (AD) imposes substantial personal, social, and economic burdens, yet current therapies provide only modest slowing of clinical decline. Recent approvals of amyloid-targeting antibodies confirm target engagement but also expose the limitations of single-target strategies in a disease shaped by interacting processes, including amyloid pathology, tau aggregation, neuroinflammation, vascular dysfunction, and metabolic disturbances. These limitations suggest that therapeutic approaches should target multiple pathways rather than isolated lesions. Over the past two decades, cancer therapy has shifted toward rational combinations, multi-target interventions, drug repurposing, and adaptive trial designs. Several of these principles are directly relevant to AD. Recent studies, including work showing that combinations of approved anticancer agents can reverse AD-related network dysfunction across multiple brain cell types, suggest that repurposing oncology drugs for neurodegeneration is biologically plausible. An added advantage is that repurposing builds on existing safety, pharmacokinetic, and clinical experience, which may reduce development time and cost. In this Perspective, we discuss how oncology-informed repurposing strategies, combined with biomarker-based enrichment, system-level pharmacology, and adaptive platform trials, could support more integrated therapeutic development for AD. We also consider practical translational and regulatory issues, including expectations for demonstrating combination benefit, managing drug-drug interactions, and navigating intellectual property pathways. Together, these cross-disciplinary strategies offer a realistic path toward treatments that can produce durable, population-level benefits.