The efficacy and safety of oral disease-modifying therapies for relapsing-remitting multiple sclerosis: A systematic review

Background: Although widely used, first-line injectable medicines for the treatment of multiple sclerosis (MS) remain an issue of efficacy and adherence. Recently, new oral medications for MS have contributed to dramatic improvements in MS treatment. This study aims to evaluate the safety and efficacy of oral disease-modifying drugs (DMDs) used in relapsing-remitting MS (RRMS). Methods: A systematic review was conducted on related databases including PubMed, Scopus, Cochrane, and Web of Science up to April 2020. The screening of the studies and their quality assessment was carried out independently by the two authors. Results: Three studies fulfilled the predefined criteria of inclusion. One of them compared teriflonomide with subcutaneous interferon beta-1a (IFN β-1a), another compared oral fingolimod with intramuscular (IM) IFN β-1b, and the third article compared oral fingolimod with IM IFN β-1a. No eligible study was found for dimethyl fumarate (DMF). The results indicated that while the efficacy of fingolimod was more than IFN β (IM β-1a and β-1b), teriflunomide 7 mg had less efficacy than subcutaneous IFN β-1a. Regarding safety, the results indicated that the proportion of diabetic patients with adverse events (AEs) in the fingolimod group was higher than in the IFN β-1b group and the overall occurrence of AEs was similar between teriflunomide and IFN β-1a groups. Conclusion: There is evidence for the effectiveness of fingolimod in reducing annualized relapse rates (ARRs) and improving magnetic resonance imaging (MRI) findings, but the evidence does not support the effectiveness of teriflunomide and further studies are required to determine its efficacy. Also, fingolimod is associated with more side effects than IFN β-1b, but there is no evidence to suggest any difference in side effects between teriflunomide and IFN β-1a.