Disease modifying therapies for relapsing multiple sclerosis

Multiple sclerosis (MS) is a common, disabling, putatively autoimmune neurological disease with worldwide distribution. It typically begins as a relapsing disorder that later evolves to a secondary progressive phase. Inflammatory and neurodegenerative mechanisms seem to operate in both phases, but their relative contributions and interactions are incompletely understood. Disease modifying therapies (DMTs) approved for relapsing multiple sclerosis interfere with a variety of immunological mechanisms to reduce rates of relapse, accumulation of disease burden measured by magnetic resonance imaging (MRI), and decline in neurological function over the two to three year duration of typical randomized controlled trials. Benefits of longer duration of therapy on disability are less clear, as data beyond three years are largely limited to observational studies. However, current DMTs do not slow accrual of disability once progressive multiple sclerosis is established. This review summarizes the evidence about the use of approved DMTs and examines how to individualize treatment despite the absence of validated biomarkers to guide drug selection. Methods such as stratifying patients on the basis of estimated risk for future disability, weighing patient specific factors and preferences, and using objective outcomes to adjudicate treatment success are discussed. Emerging drug therapies and strategies are also reviewed.