Safety and Effectiveness of Dimethyl Fumarate in Japanese Patients With Multiple Sclerosis: Subgroup Analysis of Older Patients and Patients Switching From Fingolimod or Natalizumab Using 2-Year Post-Marketing Surveillance Data

Abstract

Objectives

To evaluate the safety and effectiveness of dimethyl fumarate (DMF) in Japanese patients with multiple sclerosis (MS) in subgroups defined by baseline age and prior therapy.

Methods

This analysis used 2-year post-marketing surveillance data from all MS patients receiving DMF in Japan between February 2017 and March 2024. Safety (adverse events, lymphocyte counts) and effectiveness (annualized relapse rate [ARR]) were assessed in patients aged < 50, ≥ 50, < 15, ≥ 15–< 65, or ≥ 65 years at baseline, and in patients with no prior disease-modifying drug (DMD) therapy or switching from fingolimod or natalizumab.

Results

Of 2092 patients, baseline age was < 50 and ≥ 50 years in 1601 (76.5%) and 491 (23.5%) and < 15, ≥ 15 to < 65, and ≥ 65 years in 3 (0.1%), 2014 (96.3%), and 75 (3.6%), respectively; 576 (27.5%) had no prior DMD therapy, while 549 (26.2%), 71 (3.4%), and 896 (42.8%) had switched from fingolimod, natalizumab, and other DMDs, respectively. Lymphocyte count decreased occurred with higher incidence in the ≥ 65-year (34.7%) and prior fingolimod (40.6%) subgroups than the overall population (23.1%). Among relapsing–remitting MS patients (n = 1714), ARR significantly decreased at Years 1 and 2 after DMF initiation (−63.6% and −78.4% vs. the 1 year before DMF), with similar reductions in most age subgroups and in the no prior DMD subgroup. ARR non-significantly increased at Year 1 and decreased at Year 2 in the prior fingolimod or natalizumab subgroups.

Conclusion

DMF had consistent safety and effectiveness in Japanese MS patients, including older patients and those switching from fingolimod or natalizumab.