Multiple Sclerosis Associated Retrovirus as a Prognostic Biomarker for Prescribing Disease Modifying Therapies in Multiple Sclerosis

Multiple Sclerosis (MS) is a disease of the central nervous system with unknown etiology. Relapse remitting multiple sclerosis - the most common form of the disease, occurring in 85% of individuals diagnosed with MS – is characterized by focal lesions of inflammation, axonal degeneration, demyelination and blood brain barrier dysfunction. There are approximately 100,000 people living with MS in Canada. Classical, first-line disease modifying therapies (DMTs) such as glatiramer acetate and interferon beta have marginal efficacy in slowing disease progression. More efficacious monoclonal antibody treatments, such alemtuzumab and natalizumab, carry the risk of serious adverse side effects, including progressive multifocal leukoencephalopathy, malignancies and autoimmune diseases. Therefore, individuals who have MS may opt for less efficacious treatments due to the risk of serious adverse effects associated with more aggressive treatments. This presents a need for a prognostic biomarker to predict disease severity and to guide treatment regimens to allow patients and physicians to accurately evaluate the risks of aggressive treatment. There is mounting evidence suggesting that multiple sclerosis associated retrovirus (MSRV) has a role in MS. This article will evaluate the current literature and evaluate the potential of using MSRV as a prognostic biomarker to guide DMT prescription in Canada. Three questions will be explored: can MSRV be used as a biomarker to predict MS severity; is it feasible to screen for MSRV in individuals diagnosed with MS in Canada; and does MSRV contribute to the pathology seen in MS? The majority of the MSRV expression data in the context of MS comes from small, European studies. These studies suggest that MSRV can be used as a prognostic biomarker, and that MSRV has the potential to drive the pathology seen in MS. To feasibly investigate these questions in a large Canadian cohort, collaboration and data-sharing through a centralized database is necessary. By collecting sample data from a large spectrum of Canadian MS patients, the efficacy of MSRV as a prognostic biomarker can be sufficiently evaluated, which has the potential to change the way aggressive DMTs are prescribed in Canada.