The Ricarte Soto Law (RSL) is a Public Health program that provides universal coverage for high-cost treatment diseases. For Relapsing-Remitting Multiple Sclerosis (RRMS), this is a “rescue” program which covers financial costs of Disease Modifying Treatments (DMT) after first-line immunomodulatorshas failed . It started in July’17 covering Natalizumab and Fingolimod. By July’19 Ocrelizumab, Alemtuzumab and Cladribine were included.

OBJECTIVE: to describe treatment patterns of RRMS patients within the RSL.

METHODS: Anonymized data from the public entity in charge of healthcare supplies (CENABAST) was analyzed from July’17 to November’21.

RESULTS: we retrieved 1355 complete records for data analysis, which represents 93,2% of total RRMS patients enrolled on RSL. From July’17 to July’19, the preferred treatment was Fingolimod (77,1%), however once other treatments became available, Ocrelizumab was preferred for newly incorporated patients to RSL (56,2%) followed by Fingolimod (16,8%). DMT was changed in 13,1% of patients. These changes were unevenly distributed, 80,3% occurred before July’19, while only 19,6% happened after that date (p-value=0.0001). For each treatment, we calculated the patient-leakage percent (n° of patients who change treatment / n° of initially treated patients), finding that Natalizumab and Fingolimod had the greatest patient-leakage with 34,5% and 24,4% respectively, followed by Cladribine (5,0%), Alemtuzumab (4,8%) and Ocrelizumab (0,6%). The patient-leakage rate (velocity of change) was more steep and relatively constant over time for Natalizumab and Fingolimod. Cladribine and Ocrelizumab had the lowest patient-leakage rates (p-value=0.00001). Of all patients that changed treatment, 62,9% were switched to Ocrelizumab followed by 16,3% that switched to Cladribine.

CONCLUSIONS: Most patients remained within the same DMT,13,1% changed therapy, mostly from Fingolimod and Natalizumab towards Ocrelizumab.. After July’19 prescribing preferences for new RRMS patients favor Ocrelizumab over Fingolimod.