To analyze the safety of HETs in pwMS over 50 years old in a real life cohort from LatinAmerica.

Several epidemiological studies around the world have reported a higher prevalence of people with multiple sclerosis (pwMS) over 50 years old, under highly efficacy therapies (HETs). We don't know the safety of HET in this population since they are not included in phase 3 studies.

Retrospective cohort study including pwMS under HETs (cladribine and monoclonal antibodies) from Argentina was performed. We define two pwMS groups under HETs to compare: patients aged 50 years old or older (G1) and patients under 50 years of age (G2) as a control group (proportion 2:1), stratified by comorbidities, risk factors, and clinical characteristics and adverse events.

882 pwMS were included, 141 (15.9%) were 50 years old or more. Of this group, 47 (33.3 %) were under HETs (G1) and were compared to 81 pwMS of G2. Time under HETs: 2.06 years (SD 1.8) in G1 vs 2.2 (1.9) in G2. In a logistic regression model, adjusted for phenotype, EDSS, MS evolution, time under HET and Charlson comorbidity index, G1 pwMS group did not have a significant increase in risk of adverse events compared to G2 (adjusted OR 0.72; CI95% 0.143 -3.43, p=0.67) . Regarding G1 ocrelizumab (48.9%) was the HET most used. The most frequent adverse event in G1 was urinary tract infection (UTI) (21.3%).  We found significant differences in the frequency of UTI (p=0.004), increased in G1. We did not find significant differences in the frequency of infusion reactions, lymphopenia, neoplasms, respiratory tract infections, and liver disease. 

This is the first study in LATAM. The short term use of HETs in pwMS aged 50 years old or older was safe. Studies with a larger number of pwMS and long-term follow-up are required.