Purpose: To describe patients initiating dimethyl fumarate (DMF) and measure persistence with DMF, discontinuation, and switching in treatment-naïve DMF patients and patients switching to DMF from other multiple sclerosis disease-modifying treatments (DMTs).
Methods: A population-based cohort study of all Stockholm County residents initiating DMF from 9 May 2014 until 31 May 2017. All data were derived from a regional database that collects individual-level data on healthcare and drug utilization of all residents. The study outcomes were persistence with DMF and DMF discontinuation and switching to other DMTs. Persistence was measured as the number of days until either DMF discontinuation (treatment gap ≥ 60 days) or switching to another DMT.
Results: The study included 400 patients (median follow-up = 2.5 years). The majority had previously been treated with other DMTs (61%). Throughout the follow-up period, 124 patients (31%) discontinued DMF and 114 patients (29%) switched treatment. Overall, 34% of patients initiating DMF stopped treatment within 1 year and only 43% of patients remained on DMF at 2 years from treatment initiation.
Conclusions: DMF had a rapid market uptake likely due to high expectations held by both patients and clinicians. However, persistence with DMF in routine clinical practice was found to be low.
Keywords: Dimethyl fumarate; Drug utilization; Multiple sclerosis, relapsing-remitting; Persistence.