Treatment retention on fingolimod compared with injectable multiple sclerosis therapies in African-American patients: A subgroup analysis of a randomized phase 4 study

Background: Suboptimal persistence with injectable disease-modifying therapies (iDMTs; interferon beta-1a/b, glatiramer acetate) is common in patients with relapsing forms of multiple sclerosis (MS), reducing the effectiveness of these agents. Adherence to, and persistence with, an effective therapy is important for patient populations at increased risk of rapid disease progression. African-American individuals with multiple sclerosis may experience a more aggressive disease course than Caucasian patients, with a greater risk of developing ambulatory difficulties and other disabilities, and may also have a diminished response to some disease-modifying therapies compared with patients of other ethnicities. Retention on oral fingolimod and on iDMTs was evaluated in a post hoc analysis of data from African-American patients in the parallel-group, 48-week 'Prospective, Randomized, active-controlled, open-label study to Evaluate patient retention on Fingolimod versus approved first-line disease modifying thErapies in adults with Relapsing-remitting Multiple Sclerosis' (PREFERMS). Methods: In PREFERMS, patients with relapsing-remitting MS aged 18-65 years with an Expanded Disability Status Scale score <= 6 enrolled at 117 US study sites were treatment-naive or had received only one iDMT class. Patients were randomized 1:1 (fingolimod 0.5 mg/day:preselected iDMT) using an interactive voice-and-webresponse system without blinding, followed up quarterly, and allowed one study-approved treatment switch after 12 weeks, or earlier, for efficacy or safety reasons only. The primary outcome was patient retention on randomized treatment over 48 weeks. In this post hoc analysis of African-American patients in PREFERMS, outcome variables included rate of patient retention on randomized treatment, reasons for discontinuing randomized treatment, patient-reported treatment satisfaction, and safety. Clinical and radiographic outcomes such as annualized relapse rate, brain volume loss, and lesion count changes were also investigated. Results: In PREFERMS, 141 of 875 patients (16.1%) randomized to a study drug were African-American. Analysis of data for the full analysis set of 67 patients receiving fingolimod and 69 receiving iDMTs showed that the retention rate over 48 weeks was significantly higher with fingolimod than with iDMTs (80.6% [n = 54] vs 30.4% [n = 21]; between-group difference: 50.2%; 95% confidence interval 35.8-64.6%; p < 0.0001). The most common treatment switch was from an iDMT to fingolimod for injection-related reasons, and patient satisfaction was greater with fingolimod than with iDMTs. Adverse events were consistent with the respective prescribing information for each treatment. Conclusion: In PREFERMS, fingolimod was associated with better treatment retention than iDMTs in African-American patients. Optimal outcomes in the management of multiple sclerosis depend on good persistence with treatment, and this is particularly important in patient populations at increased risk of a rapidly progressing disease course.