Abstract
Multiple sclerosis (MS) has become a common neurological disorder involving populations previously considered to be infrequently affected. Genetic dissemination from high- to low-risk groups is a determining influence interacting with environmental and epigenetic factors, mostly unidentified. Disease modifying therapies (DMT) are effective in treating relapsing MS in variable degrees; one agent is approved for primary progressive disease, and several are in development. In the era of high-efficacy medications, complex molecules, and monoclonal antibodies (MAB), including anti-VLA4 (natalizumab), anti-CD52 (alemtuzumab), and anti-CD20 (ocrelizumab), obtaining NEDA (no evidence of disease activity) becomes an elusive accomplishment in areas of the world where access to MS therapies and care are generally limited. Countries' income and access to public MS care appear to be a shared socioeconomic challenge. This disparity is also notable in the utilization of diagnostic tools to adhere to the proposed elements of the McDonald Criteria. The impact of follow-on medications ("generics"); injectable non-biological complex drugs (NBCD), oral sphingosine-1-phosphate receptor modulators, and biosimilars (interferon 1-a and 1-b), utilized in many areas of the world, is disconcerting considering these products generally lack data documenting their efficacy and safety. Potential strategies addressing these concerns are discussed from an international point of view.