Real-world disease-modifying therapy usage in persons with relapsing-remitting multiple sclerosis: Cross-sectional data from the Swiss Multiple Sclerosis Registry.

INTRODUCTION: Several disease-modifying therapies (DMTs), covering a broad spectrum of mechanisms of action, have been approved by regulatory agencies for the treatment of relapsing-remitting multiple sclerosis (RRMS). However, only little is known about the current real-world treatment situation in Switzerland. Based on data from a diverse population of 668 persons with RRMS from the Swiss Multiple Sclerosis Registry (SMSR), the present study aims to fill this gap with a descriptive, cross-sectional approach. METHODS: Data originated from the SMSR baseline questionnaire and follow-up surveys. Data on current health status and life situation in the last 6 months were extracted from the survey distributed throughout 2020 and 2021, while data on disease-modifying therapy (DMT) histories were included from preceding surveys. Initially, data was stratified into three DMT groups according to the current DMT status (NO (No DMT), CONTINUED (DMT started more than 6 months ago), and NEW (DMT started less than 6 months ago)). In a subsequent analysis, the sample was stratified into groups corresponding to the five most frequently prescribed DMTs. Self-reported outcomes including therapy discontinuation or interruption, relapses and side-effects in the last 6 months were analyzed per group. Life and health situation parameters were also determined and analyzed. RESULTS: The study population consisted of 445 (66.6%) individuals belonging to the CONTINUED, 84 (12.6%) to the NEW, and 139 (20.8%) to the NO group. Within the NO group, 24 (17.3%) reported relapses. Furthermore, self-reported relapses (28 (33.3%)), side-effects (39 (46.4%)), and treatment discontinuations or interruptions (30 (35.7%)) occurred more frequently in the NEW compared to the CONTINUED group (37 (8.3%), 125 (28.1%), 8 (1.8%), respectively). The three groups also differed with respect to age, time since diagnosis, number of symptoms, DMT history, and health-related quality of life. The five most frequently prescribed DMTs included fingolimod (33.4%), dimethyl fumarate (25.0%), ocrelizumab (23.6%), natalizumab (10.6%) and teriflunomide (7.5%). The frequency of self-reported relapses ranged from 9.7% to 13.6%. Notable differences were found in the number of self-reported side-effects, ranging from 9.1% with natalizumab to 56.7% with dimethyl fumarate. DISCUSSION: This cross-sectional analysis suggested that the majority of individuals with RRMS in Switzerland continuously receive tolerable DMT. However, groups not receiving DMT or struggling with side-effects or continued disease worsening while on DMT still persist. It is conceivable that the number of self-reported symptoms indicates the need for more detailed clarification of the DMT characteristics and expectations of treatment outcomes. Injectable DMTs no longer play a major role in the treatment of RRMS in Switzerland and a trend toward an early use of potent drugs is emerging.