Usage trend of oral drugs for multiple sclerosis patients in Argentina

Introduction: Over the past decade, numerous disease modifying drugs (DMDs) for relapsing- remitting multiple sclerosis (RRMS) have been approved in Argentina. The use of oral DMDs (oDMDs) has increased in recent years, although real-life data in our region is limited. We aimed to describe the tendency in the use of oDMDs (as first treatment option or after switch) in relationship with their approval in Argentina. Methods: A retrospective study in a cohort of MS patients from five Argentinian MS centers was conducted. Regarding the availability of different oDMDs in Argentina, we define three periods (P1-3): P1: 2012 - 2014; P2: 2015 - 2017 and P3: 2018 - 2020. An analysis was performed comparing between these three periods to assess the tendency for oDMDs use over time. Result: The most frequently prescribed treatment as first DMD was: interferon beta la (40%) in P1, fingolimod (37.3%) in P2 and also fingolimod (35%) in P3. We found an increase in the use of oDMTs as initial treatment over time (P1: 17.7%, P2: 63.9% and P3: 65.0%; Chi-square = 41.9 p <0.01). We also found a tendency to increase the use of oDMTs after a first switch (P1: 45.5%, P2: 60.1% and P3 78.3%). Multivariate analysis showed that disease evolution (OR=1.06, p=0.04), and year of treatment initiation (OR=1.01 p<0.01) were independently associated with choice of oDMTs. Conclusion: This study identified an increasing tendency for the use of oDMDs as initial treatment of RMS in relationship with their approval in Argentina.