Comparative effectiveness and safety of rituximab versus ocrelizumab in relapsing-remitting multiple sclerosis: a real-world experience from Iran.

Abstract

Introduction: Anti-CD20 monoclonal antibodies are regarded as high-efficacy disease-modifying therapy (DMT) for relapse-remitting multiple sclerosis (RRMS). Herein, we aimed to compare the effectiveness and safety of OCR and RTX in patients with RRMS.

Methods and materials: Between 2020 and 2025, RRMS patients prescribed OCR or RTX at the Imam Hossein MS Center in Tehran, Iran, were identified. Clinician-reported data were retrospectively extracted from medical records using a standardized data-collection checklist. Treatment allocation was non-random and was influenced by insurance coverage and drug availability. Rituximab was commonly administered using an extended-interval dosing protocol. Comparative analyses used survival methods and regression analyses. A two-sided P value < 0.05 indicated statistical significance.

Results: 150 patients (OCR = 90, RTX = 60) were followed for a mean of 42.1 ± 15.1 months (RTX: 46.2 ± 19.1 months; OCR: 39.5 ± 11.0 months; P = 0.12). Baseline demographic and MS-related characteristics were comparable. The annualized relapse rate (ARR) decreased from a pre-treatment mean of 1.23 to 0.70 in the OCR group and 0.76 in the RTX group (mean difference, - 0.06; P = 0.34), with corresponding absolute relapse counts of one in the OCR group and two in the RTX group. Confirmed disability worsening occurred in five patients (1 OCR, 4 RTX; P = 0.16). Among patients with follow-up MRI data (n = 115), new asymptomatic MRI activity was observed in 4.4% of OCR-treated and 5.0% RTX-treated (P = 0.99) patients. Secondary hypogammaglobulinemia (SHG) occurred in 17/90 (18.9%) of OCR-treated and 10/60 (16.7%) of RTX-treated patients, (P = 0.60), which was mainly asymptomatic. Treatment persistence was high in both groups (OCR 98.9%, RTX 93.3%).

Conclusion: Over a mean follow-up exceeding three years, no statistically significant differences in relapse, MRI, or disability outcomes were detected between OCR and RTX. Because treatment allocation was non-random and RTX was commonly administered using extended-interval dosing, these findings represent a comparison of real-world treatment strategies, not a causal comparison of the intrinsic effects of RTX versus OCR.