RESUMO
Background: Cladribine shows efficacy in multiple sclerosis (MS), but Latin American (LATAM) real-world data is limited, despite potential sociodemographic variations. Objective: Investigate baseline characteristics and clinical response in highly active MS patients in Mexico, identifying predictors of early treatment response. Method: A multicenter cohort study analyzed retrospective data from individuals with "highly active" MS in the Cladribine Patient Support Program across 11 Mexican clinics. Criteria included one-year prior treatment with another disease-modifying treatment and recent relapse with specific MRI findings. Primary outcomes focused on achieving NEDA-3 status after 12 months. Results: In the follow-up, 67.5% maintained NEDA-3 status. Baseline EDSS scores decreased significantly from 1.50 to 1.00 (p = 0.011), with no confirmed disability worsening. No significant differences were observed between NEDA-3 achievers and non-achievers in demographic and clinical variables. No severe adverse events were reported. Conclusion: Cladribine showed early and effective control of active MS in Mexican patients, demonstrating a secure profile with minimal adverse events. This study provides valuable real-world evidence in the LATAM context.