Introduction: Clinical course and treatment response may vary according to race/ethnicity in multiple sclerosis (MS) patients. Delayed-release dimethyl fumarate (DMF; also known as gastro-resistant DMF) demonstrated significant efficacy and a favorable benefit-risk profile in relapsing-remitting MS (RRMS) patients in the 2-year phase III DEFINE/CONFIRM studies.
Methods: In this post hoc analysis of integrated data from DEFINE/CONFIRM, we assessed clinical efficacy and safety/tolerability in black, Hispanic, and Asian patients treated with DMF 240 mg twice daily (approved dosage) or placebo. Eligible patients were 18-55 years of age with an Expanded Disability Status Scale score of 0-5.0. In the integrated intention-to-treat population, 769 and 771 patients were treated with DMF or placebo, respectively, of whom 10 and 19 were black, 31 and 23 were Hispanic, and 66 and 70 were Asian.
Results: In the black, Hispanic, and Asian subgroups, DMF was associated with lower annualized relapse rates at 2 years compared with placebo [rate ratio (95% confidence interval (CI)), 0.05 (0.00-1.07); 0.31 (0.10-0.95); and 0.64 (0.30-1.34), respectively]. The percentage of black, Hispanic, and Asian patients with 12-week confirmed disability progression was lower with DMF (43%, 8%, and 20%, respectively) compared with placebo [57%, 30%, and 25%, respectively; hazard ratio (95% CI), 0.53 (0.02-1.39); 0.17 (0.00-0.60); and 0.71 (0.32-1.58), respectively]. The safety/tolerability profile of DMF was generally consistent with that in the overall population of DEFINE/CONFIRM. The incidence of adverse events leading to treatment discontinuation in black, Hispanic, and Asian patients was 2/10, 2/31, and 3/66, respectively, with DMF, and 2/19, 1/23, and 8/70, respectively, with placebo.
Conclusion: DMF may be an efficacious treatment with a favorable benefit-risk profile in black, Hispanic, and Asian patients with RRMS. Further clinical studies are needed to characterize differences in MS presentation and treatment outcomes across ethnic and racial groups.
Trial registration: DEFINE: ClinicalTrials.gov identifier NCT00420212; CONFIRM ClinicalTrials.gov identifier NCT00451451.
Keywords: Delayed-release dimethyl fumarate; Efficacy; Ethnicity; Race; Relapsing-remitting multiple sclerosis; Tolerability.