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

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