Abstract
Background: The advent of new, potent, disease-modifying therapies has dramatically changed the management of multiple sclerosis (MS). Along with these possibilities, it is crucial to better recognize patients who are at risk of first line treatment (FLT) failure and switch to highly effective therapies (HET).Objectives: To identify baseline prognostic factors associated with FLT failure in relapsing remitting MS (RR-MS) patients.Methods: We included recently diagnosed RR-MS patients starting an FLT identified from 3 French MS centers databases. Baseline characteristics were included in a multivariable Cox analysis to identify the main factors associated with FLT failure.Results: Eight hundred sixty-three patients were included. We observed an overall rate of treatment failure of 23.5%. The main baseline characteristics associated with treatment failure were age <26 years at treatment start (HR= 2.1, p<0.001), EDSS ≥2 (HR=2.1, p<0.001) and ≥2relapses in the previous year (HR=1.5, p=0.04). The association with the presence of gadolinium enhancement on MRI was not statistically significant. EDSS progression was only significantly associated with age at treatment start and treatment failure.Conclusion: Our series demonstrates that some clinical and imaging factors are associated with treatment failure, and should be considered when planning treatment strategy in patients with recently diagnosed RR-MS.