Long-term effectiveness and safety of ocrelizumab: a single-centre real-world study

This retrospective single-centre study evaluated the effectiveness and safety of ocrelizumab (OCR) in relapse-onset multiple sclerosis (RMS) and primary progressive MS (PPMS) and identified predictors of treatment response.

We included 260 RMS and 73 PPMS patients treated with ocrelizumab for ≥ 1 year at our MS Centre until May 2024.

Median follow-up was 3.90 years for RMS and 4.23 years for PPMS. Within 2 years from treatment initiation, annualized relapse rate (ARR) decreased from 0.412 to 0.014 and was maintained low throughout follow-up in RMS, with no relapses in PPMS. MRI activity significantly declined and was maintained in both groups (p < 0.0001). After 3 years, confirmed disability progression (CDP)-free survival was high in relapsing-remitting MS (> 97%) and lower in secondary progressive MS (48.9%) and PPMS (57.2%). Predictors of ocrelizumab inefficacy included higher baseline Expanded Disability Status Scale (EDSS), older age and longer disease duration in RMS; male sex, older age and prior lower-efficacy treatments in PPMS. Adverse events were in line with previous clinical studies, with hypogammaglobulinemia and recurrent infections being the most frequent.

In this study we confirm ocrelizumab sustained efficacy in controlling inflammatory disease activity, with greater impact in RMS, with a favourable safety profile. Early treatment initiation is crucial to prevent irreversible disability accumulation.