Multiple Sclerosis Patients Treated With Diroximel Fumarate in the Real-World Setting Have High Rates of Persistence and Adherence.

Introduction Persistence to multiple sclerosis (MS) disease-modifying therapy is fundamental for maximal treatment outcomes. Diroximel fumarate (DRF) is approved in the USA for relapsing MS. Following oral administration, DRF is metabolized to monomethyl fumarate, the active metabolite of dimethyl fumarate (DMF). DRF showed clinically significant improvements in gastrointestinal (GI) tolerability versus DMF in a head-to-head clinical trial; however, real-world persistence/adherence has not been assessed. We evaluated persistence/adherence in DRF-treated patients in a real-world clinical practice. Methods This retrospective analysis of the AcariaHealth Specialty Pharmacy Program included patients initiating DRF from 4 December 2019 through 3 April 2020 and followed until data extraction (31 August 2020). Exclusion criteria included undetermined treatment status (e.g., DRF prescription transfer to a different pharmacy). Endpoints included persistence (overall proportion of patients remaining on DRF), discontinuation rate due to GI adverse events (AEs), and adherence (proportion of days covered [PDC]). GI AEs included GI-related AEs occurring at any time, or any unknown AE without details about the nature of the event if the unknown AE occurred ≤ 90 days after DRF initiation. Results Overall, 160 patients with MS were included. Median (range) patient age was 51 (20-79) years, 80.6% (129/160) of patients were female, and 16.3% (26/160) had prior DMF treatment. Median (range) treatment duration was 7.6 (0.1-10.4) months. Estimated proportion of patients remaining persistent on DRF treatment at 8 months was 88.6% (95% confidence interval [CI] 82.5-2.7). Overall, 3.8% (6/160) of patients discontinued due to GI AEs. Mean PDC was 91.4% (95% CI 89.1-93.7). In a DMF-to-DRF switch subgroup, 92.3% (24/26) remained persistent on DRF, and 3.8% (1/26) discontinued DRF due to GI AEs. Conclusion This real-world analysis of DRF-treated patients showed high overall persistence, low discontinuation rate due to GI AEs, and high adherence to therapy, aligning with expectations based on DRF clinical trials. Data were consistent in the DMF-to-DRF subgroup. INFOGRAPHIC.