Adherence and discontinuation rates in patients on Tecfidera™ (dimethyl fumarate): Long-term Canadian experience from the Biogen ONE™ support program

Background: Tecfidera™ (dimethyl fumarate [DMF]; Biogen) is an oral disease-modifying therapy (DMT) indicated in Canada for the treatment of relapsing-remitting multiple sclerosis (MS). Biogen ONE™, an ongoing Canadian support program, facilitates access to DMF for patients with MS and maintains a database for the purposes of service provision. These data were utilized to assess adherence, persistence, discontinuations, and other outcomes between 2013 and 2021.

Methods: This non-interventional, retrospective study examined real-world use of DMF prescribed to patients with MS in Canada who were enrolled in the program and received their first dose between April 1, 2013, and June 30, 2021. Follow-up visits and laboratory monitoring occurred based on local standards and per the Canadian product monograph. For adherence and persistence assessments, patients must have had DMF dispensed by specialty pharmacies. Data were collected at patient enrollment, program exit, and throughout the duration of the program. The primary objective was to assess treatment adherence rates to DMF. Secondary objectives included treatment persistence rates, reasons for discontinuation, absolute lymphocyte counts (ALCs), and patient characteristics throughout the duration of the program.

Results: Overall, 12,608 DMF patients from the program were included between April 1, 2013, and June 30, 2021. At enrollment, mean (standard deviation [SD]) age was 40.6 (10.7) years and mean (SD) Expanded Disability Status Scale (EDSS) score was 2.2 (1.4). DMF was initiated as first-line DMT in 48.8% of patients. Of patients assessed (n = 6,848), 90.4% were adherent to DMF (based on medication possession ratio [MPR] ≥ 80%). Adherence (mean MPR) was marginally greater in DMT-naïve than switch patients, and in younger (< 40 years) than older (≥ 40 years) patients (both p < 0.001). Overall persistence on DMF at 24 months was 57.0%. Greater proportions of DMT-naïve patients persisted on DMF versus switch patients at all time points assessed. Persistence rates were comparable between female and male patients for up to 24 months, and between younger (< 40 years) and older (≥ 40 years) patients for up to 36 months. Older patients were more likely to discontinue for reasons related to lymphocytes (≥ 40 years, 16.1% vs. < 40 years, 6.1%) while efficacy reasons were reported with greater frequency in younger patients (≥ 40 years, 10.5% vs. < 40 years, 16.0%). Discontinuations due to gastrointestinal and flushing events occurred most frequently during the first month of treatment and decreased thereafter. Mean ALC decreased during the first year on treatment and subsequently plateaued. Over successive years, changes were observed in characteristics of patients starting on DMF, including decreases in EDSS score, age, and time since diagnosis. The proportion of DMT-naïve patients increased over the years (2013-2014, 26%-27%; 2018-2021, 62%-67%).

Conclusions: High adherence was found in patients on DMF treatment within the Biogen support program with access to specialty pharmacies. The evolution of the patient population throughout the years suggests a shift towards earlier treatment. These real-world data may support the value of a support program in optimizing the management of patients on DMF treatment. Support programs provide personalized treatment monitoring, which can help minimize early discontinuations and improve adherence to treatment.