An updated systematic review and meta-analysis exploring the efficacy and safety of dimethyl fumarate (DMF) for patients with multiple sclerosis (MS).

Background: Dimethyl fumarate (DMF) is increasingly used in treating multiple sclerosis (MS) with controversial results of the safety and efficacy of different DMF doses. We aimed to systematically review the literature to examine the safety and efficacy of DMF for MS patients. Methods: We searched PubMed Medline, Cochrane, Web of Science, Scopus databases and clinicaltrials.gov up to June 2023 for the published trials evaluating the use of DMF for MS in adults. All included studies were screened and abstracted independently by two authors. Efficacy and safety outcome measures were extracted. The meta-analysis was conducted using Review Manager 5.4. Results: 10 studies including eight randomised controlled trials, one open-label and one single-arm before-after study with a total population size of 4278 patients were included. DMF group showed a statistically significant reduction in the proportion of relapses compared with the control group, (OR: 0.47, 95% CI: [0.41, 0.55], p<0.00001) with no statistical differences between 240 mg two times per day and three times a day doses. Furthermore, the DMF group had a significant reduction in Gd-enhanced lesions compared with control (MD=-1.53, 95% CI: [-1.91 to -1.41], p<0.00001). Our results showed a non-significant difference in adverse events that led to discontinuation of the study with an OR of 1.29 (95% CI: [0.98, 1.71], p value=0.07). Discussion: DMF had significant efficacy and safety compared with the control, with no difference between the DMF doses. More studies with large sample sizes and longer follow-ups are needed to detect long-term safety and efficacy.