OBJECTIVES

This study aims at assessing prevalence, clinical, therapeutic characteristics of relapsing multiple sclerosis (RMS) patients in the Italian Multiple Sclerosis Registry (IMSR), to evaluate the percentage of patients that switch DMT due to changes in disease activity (relapses and/or evidence of new MRI activity in 2 years before data extraction) in RMS patients and describe the different drivers of therapy switch that occurs during disease course.

METHODS

We measured MS patients’ demographics and disease course characteristics, DMT treatment patterns and EDSS score evolution throughout the MS course. To evaluate how disease activity impact treatment switch we have first determined the proportion of patients with "on treatment relapses", then we evaluated how these disease activity measures influence the treatment switch.The association between disease activity and switch therapies has been evaluated with the best regression model, as suggested by goodness of fit performed on several models.

RESULTS:

The final cohort includes 17,013 relepsing remitting (RRMS) patients and 575 secondary progressive (SPMS) patients. Using clinical definition of active RRMS and active SPMS we identified 4161 (19.7% of the RRMS cohort) and 578 (50.1% of the SPMS cohort) patients with active disease phenotype, respectively. Active patients were significantly younger, less disabled and more frequently affected by relapsing disease course (89.8% vs 85.2%, p<0.0001) in comparison not active patients. Among active patients 2694 (56.8%) switched their DMT due to recent clinical disease activity. We also assessed different drivers of therapy switch that occur during disease course.

CONCLUSIONS

Our findings indicate that an active course of disease is the main factor determining the treatment switch both in RRMS and in SPMS patients. Moreover, our results highlight the strong efficacy of second line DMTs, in reducing the risk of clinical disease activity during both the RR and the SP phase of the disease.