Evaluation of drivers of treatment switch in relapsing multiple sclerosis: a study from the Italian MS Registry

Background Active relapsing–remitting (RR) and secondary progressive (SP) multiple sclerosis (MS) are currently defined as “relapsing MS” (RMS). The aim of this cross-sectional study was to assess drivers of treatment switches due to clinical relapses in a population of RMS patients collected in the Italian MS and Related Disorders Register (I-MS&RD). Methods RRMS and SPMS patients with at least one relapse in a time window of 2 years before of data extraction were defined as RMS. Factors associated with disease-modifying therapy (DMT) switching due to clinical activity were assessed through multivariable logistic regression models in which treatment exposure was included as the last recorded DMT and the last DMT’s class [moderate-efficacy (ME), high-efficacy (HE) DMTs and anti-CD20 drugs]. Results A cohort of 4739 RMS patients (4161 RRMS, 578 SPMS) was extracted from the I-MS&RD. A total of 2694 patients switching DMTs due to relapses were identified. Switchers were significantly ( p