Persistence, Adherence, and Switching to Higher-Cost Therapy in Patients with Multiple Sclerosis Initiating Oral Disease-Modifying Therapies: A Retrospective Real-World Study

INTRODUCTION: Therapeutic efficacy of disease-modifying therapies (DMTs) for multiple sclerosis (MS) is often hindered by poor persistence and adherence, impacted by patient-perceived efficacy concerns, adverse effects, inconvenience, and forgetfulness. This study measured persistence, adherence, and time to switching to higher-cost therapy among patients with MS initiating teriflunomide, dimethyl fumarate, fingolimod, or diroximel fumarate treatment. METHODS: This retrospective study used Symphony Health US claims data from patients with MS newly initiated on one of four oral DMTs between January and June 2020. Persistence was defined as the duration a patient continued their medication. Adherence was measured using medication possession ratio (MPR); patients with MPR ≥ 80% were considered adherent. Switching was measured by comparing proportions of patients switching and mean time to switch to one of three higher-cost therapies (ocrelizumab, natalizumab, or cladribine). Kaplan–Meier curves assessed persistence. Chi-square tests determined proportions of patients on therapy after 12 months. RESULTS: A total of 6934 patients newly initiated on oral DMTs met study inclusion criteria (teriflunomide, n = 1968; dimethyl fumarate, n = 3409; diroximel fumarate, n = 616; fingolimod, n = 941). Patients newly initiated on teriflunomide and fingolimod had significantly higher persistence rates after 12 months (60% and 66%, respectively vs 44% dimethyl fumarate and 49% diroximel fumarate; p < 0.0001), and the highest proportion of adherent patients at 6 months (71% and 76%, vs 60% dimethyl fumarate and 58% diroximel fumarate) and 12 months (55% and 59%, vs 40% dimethyl fumarate and 44% diroximel fumarate). Mean time to switching to higher-cost therapies ranged from 247 days (diroximel fumarate to natalizumab) to 342 days (teriflunomide to ocrelizumab), with the highest rate of switching in patients on dimethyl fumarate (7%). CONCLUSION: Patients newly initiated on teriflunomide and fingolimod had better real-world persistence and adherence at 6 and 12 months, and longer time to switch to higher-cost therapies, than patients on dimethyl fumarate or diroximel fumarate. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40120-022-00404-1.