Real-world discontinuation rate of teriflunomide and dimethyl fumarate in multiple sclerosis

BACKGROUND: For patients with MS, medication switches increase the risk of disease reactivation. OBJECTIVE: Compare discontinuation rates due to treatment failure or side effects between teriflunomide and dimethyl fumarate, and investigate clinical variables affecting discontinuation rates. METHODS: All patients who received teriflunomide or dimethyl fumarate at Haukeland University Hospital from 2013 until 2018 were identified. Clinical and demographic variables were extracted from the Norwegian MS Registry. Cause-specific Cox regression models estimated the rate of discontinuation due to treatment failure or side effects. RESULTS: We included 354 patients treated with either dimethyl fumarate (n = 185) or teriflunomide (n = 169). We found 38% lower risk of discontinuation because of treatment failure for patients using dimethyl fumarate compared to teriflunomide (p < 0.05). In a treatment-naive subgroup (n = 183), we found a 38% reduced risk of discontinuation for any reason among patients using dimethyl fumarate (p < 0.05). There was no significant difference between treatment groups in discontinuation rate due to side effects, although more patients reported side effects when treated with dimethyl fumarate. CONCLUSION: Our findings suggests that dimethyl fumarate has a lower risk of discontinuation because of treatment failure among both treatment-experienced and treatment-naive patients.