Objective: The EPOC study assessed the effects of switching from an injectable disease-modifying therapy (glatiramer acetate or one of three interferon beta drugs) to once-daily, oral fingolimod 0.5 mg in patients with relapsing MS. Outcomes were assessed in several patient subgroups at 6 months between patients who switched to fingolimod and those who continued on iDMT.Methods: Differences in study endpoints between those who switched to fingolimod and those who continued on an iDMT were evaluated by age, gender, baseline Expanded Disability Status Scale score, MS duration, number of relapses in the previous year, previous treatment, previous treatment duration, and reason for switching. The primary endpoint was the change from baseline to month 6 in the Treatment Satisfaction Questionnaire for Medication Global Satisfaction score. Secondary endpoints were changes in scores for the TSQM Effectiveness, Side Effects and Convenience subscales, Beck Depression Inventory-II, Fatigue Severity Scale, Patient-Reported Outcome Indices for Multiple Sclerosis Activities subscale and the 36-item Short-Form Health Survey. Physician-assessed Clinical Global Impressions of Improvement score at 6 months was also recorded.Results: Switching to fingolimod from iDMT significantly improved scores in all subgroups for TSQM Global Satisfaction at month 6 (all comparisons p≤0.001). Switching to fingolimod significantly improved secondary endpoint scores across all scales for most subgroups (p<0.05) with a few exceptions: switching to fingolimod improved PRIMUS Activities scores only in patients with baseline EDSS scores of greater than 2.5 (p<0.05), and did not improve FSS scores in patients who were male, switched for efficacy reasons, received previous glatiramer acetate, or in whom MS symptom onset had occurred less than 3 years ago. For SF-36 scores, the benefit of switching to fingolimod was highly variable. Conclusion:Switching to fingolimod from iDMT improved outcomes versus continuing on iDMT, including for overall treatment satisfaction, in patients with MS with wide-ranging baseline characteristics.