Effectiveness of teriflunomide in patients with relapsing multiple sclerosis who switched from other disease-modifying therapies.

To examine effectiveness of teriflunomide in patients with multiple sclerosis (MS) who switched to teriflunomide from other disease-modifying therapies (DMTs). Retrospective, observational, pre-post analysis of adults with relapsing MS (RMS; relapsing-remitting MS or active secondary progressive MS [aSPMS]) with prescription for teriflunomide between September 1, 2012, and March 31, 2019, and had been treated with another disease-modifying therapy ("switched"). Data were extracted from medical-chart data from a single US neurology center in California. Index was the date of teriflunomide initiation. Data were extracted at 1-year pre-index, index, and 1- and 2-years post-index. Patients were observed until death, loss to follow-up, or study end. A subgroup of patients with aSPMS were also examined. For inferential comparisons, significance was assessed using paired T-test or Wilcoxon rank sum test, as appropriate. P < .05 was considered significant. Eighty patients with RMS formed the main analysis. At index, mean (±SD) age was 44.0 ± 14.6 years, 71.3% were female, mean duration of MS was 9.3 ± 6.4 years. Mean duration of teriflunomide use was 24.9 ± 14.2 months. Magnetic resonance imaging of lesions were "stable" or "improved" in most patients at baseline (92.5%), at 1-year (95.1%) or 2-years (97.6%). Mean annualized relapse rate decreased by 80.8%, from 0.26 at 1-year pre-teriflunomide initiation to 0.05 at 2-years post-index (P < .001). Mean Expanded Disability Status Scale (EDSS) score slightly increased from 1-year pre-index to 1-year post-index (3.84 vs 3.90, respectively; difference: -0.06 [P = .033]) but was nonsignificant from index to 2-years post-index (3.84 vs 3.94; difference: -0.06 [P = .058]). Montreal Cognitive Assessment and timed 25-foot walk test scores remained stable through follow-up. A decrease in proportion of patients with lymphopenia was recorded from index (30.0%) to 2-years post-index (1.3%). In the subset of patients with aSPMS (n = 32), mean annualized relapse rate reduced from 1-year pre-index to 2-years post-index (0.4 vs 0.03; change: -0.38 [P < .001]). EDSS, Montreal Cognitive Assessment, and timed 25-foot walk test scores remained stable in patients with aSPMS. After switching to teriflunomide, patients with RMS (relapsing-remitting MS or aSPMS) experienced a reduction in relapses and evidence for recovery from lymphopenia. Other markers of disability worsening, including EDSS, remained stable after switching to teriflunomide.