Recent Advances in the Treatment for Multiple Sclerosis; Current New Drugs Specific for Multiple Sclerosis

Since the first approved parenteral drug for the treatment of multiple sclerosis (MS) in 1993 (interferon [IFN] beta, and later glatiramer acetate [GA]), today there are both parenteral and oral treatment options for MS. After IFN beta preparations, glatiramer acetate was developed; and, until the approval of natalizumab in 2006, those dominated the treatment of MS. Later on, among oral drug options, cladribine made a promising entry; however, due to safety concerns, it was withdrawn soon. Afterwards, with the understanding of the role of sphingosine-1 phosphate (S1P) receptors in the pathogenesis of MS, fingolimod was approved in 2010, which was followed by other oral agents such as teriflunomide and dimethyl fumarate. Recently newer IV treatment options such as alemtuzumab, rituximab and ocrelizumab have widened the treatment arena. Recently, after submitting new efficacy and safety data, cladribine was approved for MS by EMA, in 2017. Moreover, seven years after its rejection due to safety reasons, in August 2018 FDA accepted to re-evaluate the data of cladribine as a treatment option for relapsing remitting MS (RRMS). Another oral treatment option, Laquinimod, was not approved because it could not be shown to slow disability progression despite favourable effect in relapsing MS. Newer generation S1P receptor modulators are being investigated currently, and they are expected to come into the treatment arena soon. In this article, mechanisms of actions, clinical trial results, and side effects of the newer drugs used for MS, are reviewed. IFN beta and glatiramer acetate were not included since they have clinical experience nearing 30 years.