Disease-modifying therapies for Parkinson disease: lessons from multiple sclerosis

The development of disease-modifying therapies (DMTs) for chronic neurological disorders, such as multiple sclerosis (MS) and Parkinson’s disease (PD), is a critical goal in modern neurology. While significant strides have been made in MS treatment, with numerous DMTs now available, PD patients still lack similar options and must rely on treatments that only address symptoms. In November 2022, an international symposium held in Toronto, Canada, brought together researchers and experts to discuss how lessons from MS therapy development could be applied to PD. The discussions focused on therapeutic targets, preclinical models, disease subtypes, and clinical trial designs, aiming to chart a roadmap for future PD DMT development. Here are the key takeaways: Current Landscape of DMTs: There are at least 18 DMTs approved for relapsing forms of MS, with the first DMT for progressive MS also introduced. However, no DMTs currently exist for PD, leaving patients dependent on treatments that primarily offer symptom management. New Therapeutic Targets: Genome-wide studies have revealed risk genes for both MS and PD, providing new insights into potential targets for DMTs. Additionally, research into how the immune system links the brain and gut microbiota could reveal new therapeutic strategies. Preclinical Models: Both fields need more robust preclinical models, including animal models and stem cell-based systems, to better understand the underlying biology of these diseases. These models could help capture the range of disease mechanisms, offering a clearer path to therapy development. Early Disease Detection: MRI and α-synuclein seed amplification assays are helping detect the early, or prodromal, stages of MS and PD. In MS, trials have shown that DMTs can be beneficial in these early stages, offering hope that similar strategies could be applied to PD. Challenges in Disease Subtyping: MS and PD present with a wide variety of symptoms, making it difficult to classify patients based on clinical features alone. New classification systems based on molecular mechanisms might provide a more accurate way to categorize and treat patients. Measuring Treatment Effectiveness: MRI has been instrumental in assessing treatment efficacy for relapsing MS, but there is a need for reliable outcome measures for both progressive MS and PD to improve the development of DMTs in these areas. By exploring these strategies and addressing shared challenges, researchers hope to advance the development of effective DMTs for Parkinson’s disease, just as they have for MS. As understanding grows, these findings could eventually lead to breakthroughs in treating both conditions, offering patients more than just symptom relief.