Evaluation of the 24-Month Effectiveness of Disease-Modifying Therapies in Multiple Sclerosis

Abstract

Objective. To evaluate the 24-month clinical and radiological effectiveness of disease-modifying therapies (DMTs) in multiple sclerosis (MS). Materials and methods. This retrospective comparative analytic cohort study included 231 patients who initiated DMT within ≤6 months after diagnosis, remained on treatment continuously for at least 24 months, and had a baseline Expanded Disability Status Scale (EDSS) score of 0–6.5, as well as 197 patients who did not receive DMT for various reasons. In 408 patients with clinically isolated syndrome (CIS) or relapsing-remitting MS (RRMS), relapse status, annualized relapse rate (ARR), EDSS, confirmed disability progression (CDP), annualized disability progression (ADP), MRI activity, no evidence of disease activity (NEDA-3), and the composite endpoint of NEDA-3 plus absence of brain atrophy were compared at 12 and 24 months. Results. The odds of remaining relapse-free were higher in the treated group at both 12 and 24 months (OR=2.499; 95% CI 1.474-4.235 and OR=3.418; 95% CI 1.884-6.198, respectively). ARR, EDSS, ΔEDSS, and ADP were lower, whereas the absence of CDP was more frequent in treated patients (all p<0.001). Absence of MRI activity was observed in 42.9% at 12 months and 37.2% at 24 months in the treated group, significantly higher than in untreated patients (p<0.001). NEDA-3 rates were 26.5% versus 12.6% at 12 months and 22.1% versus 8.2% at 24 months. The combined endpoint of NEDA-3 and no brain atrophy was also more frequent among treated patients. Conclusion. Early and sustained DMT use was associated with lower relapse burden, slower disability accumulation, less MRI activity, and a higher likelihood of achieving NEDA-3 during 24 months of follow-up.