Advances in neurological therapies: A review of clinical trials in Alzheimer's, Parkinson's, and multiple sclerosis.

The period from 2020 to 2025 marked a pivotal juncture in the treatment of major neurological diseases, with Phase II-IV trials delivering the first compelling evidence for disease-modifying interventions in Alzheimer's disease, Parkinson's disease, and multiple sclerosis. This narrative review provides a critical analysis of this evolving therapeutic landscape, focusing on efficacy, safety, and practical implications. Our analysis reveals unprecedented yet heterogeneous progress. In Alzheimer's disease, anti-amyloid monoclonal antibodies (donanemab, lecanemab) achieved regulatory approval, establishing a new treatment paradigm despite modest efficacy and risks of amyloid-related imaging abnormalities (ARIA). In Parkinson's disease, GLP-1 receptor agonists (lixisenatide) demonstrated the first convincing disease modification signals in Phase II trials. For multiple sclerosis, the failure of Bruton's tyrosine kinase (BTK) inhibitors contrasted with the consolidation of anti-CD20 therapies as the therapeutic standard, refined by innovations in dosing and delivery. Collectively, these findings herald a new era of disease-modifying therapy in neurology, though current gains remain limited and dependent on biomarker stratification and safety monitoring. The challenge ahead is translating these successes into accessible, sustainable clinical benefits.