Precision therapeutics and innovative clinical trial design in neurodegenerative diseases.

Neurodegenerative diseases are biologically heterogeneous disorders characterized by progressive neuronal dysfunction, overlapping molecular pathologies, and limited disease-modifying therapies. Advances in biomarker development, molecular staging, and precision medicine are reshaping therapeutic strategies and clinical trial design across Parkinson's disease, Alzheimer's disease, frontotemporal dementia, amyotrophic lateral sclerosis, Huntington's disease, and related disorders. This review summarizes emerging therapeutic approaches, including monoclonal antibodies targeting protein aggregation, immune-modulating and metabolic interventions, antisense oligonucleotides, gene replacement and genome-editing strategies, stem cell-based therapies, and neurosurgical delivery platforms and neuromodulation technologies. It also examines evolving clinical trial methodologies such as biomarker-enriched recruitment, adaptive and delayed-start designs, platform trials, decentralized models, and master protocols. Additional emphasis is placed on diagnostic biomarkers, multimodal artificial-intelligence pipelines, systems-biology perspectives, network-based therapeutic strategies, and the reproducibility and interpretability requirements for computational tools. Despite recent progress, major challenges remain, including biological heterogeneity, limited translatability of preclinical models, delivery barriers, long-term safety concerns, and inequities in access to biomarker-based care and trial participation. Future directions will require combination therapies, integrated biomarker pipelines, preventive strategies, and pragmatic trial systems capable of translating biological advances into durable and equitable clinical benefit.