Evaluation of Ocrelizumab (Xacrel) on Walking Ability in Multiple Sclerosis Patients: A First Report From Iran

Introduction: Ocrelizumab (OCR) and rituximab (RTX) are monoclonal antibodies targeting CD20 on B cells, a promising approach for relapsing–remitting multiple sclerosis (RRMS) and primary progressive MS (PPMS). They aim to modulate the immune system and reduce B cells, potentially leading to fewer relapses and delayed disease progression. Xacrel, the Iranian-made OCR biosimilar, requires further investigation for its effectiveness in MS treatment. The Timed 25-Foot Walk (T25FW) has been one of the key implements for assessing mobility in MS patients for over two decades, and recent studies confirmed that comprehensive treatment—especially with fampridine and OCR—significantly improves T25FW performance.

Objective: We aim to assess the effectiveness of Xacrel (Iranian OCR) for MS treatment by evaluating alteration in Expanded Disability Status Scale (EDSS) score and T25FW test. This study also explores the potential benefits of switching patients’ drug from RTX to OCR.

Material and Methods: This prospective cohort study at Qaem Hospital (February 2022–May 2024) on 143 MS patients evaluates Xacrel in MS patients using EDSS and T25FW scores before treatment and at 6 and 12 months posttreatment. Additionally, we assessed 29 MS patients whose drug transitioned from RTX to OCR to compare the effectiveness of these treatments. For this purpose, MS progression was assessed using the EDSS score and T25FW test at baseline, 6 months, and 12 months after switching their medication.

Results: In our study, the average age was 38.48 ± 8.73 years, and over 70% were women. 76.2% were between 30–50 years old, with a mean disease duration of 6 years. About 19.6% were treatment-naive, with dimethyl fumarate as the most common first-line drug. Over 12 months, significant declines in EDSS scores and increases in T25FW tests were noted at 6 and 12 months compared to baseline (all p < 0.05), but not between 6 and 12 months. Significant factors were RRMS for 6-month EDSS score changes (p = 0.011) and treatment-naive patients for T25FW at 6 months (p = 0.018) and 12 months (p = 0.004). Switching from RTX to OCR showed no significant changes in EDSS or T25FW scores, despite trends of decreases in EDSS and increases in T25FW times at 6 and 12 months. Subgroup analyses by gender, age, disease duration, type, and previous medication history showed no significant differences.

Conclusion: In MS patients—particularly treatment-naive individuals and those with RRMS—Xacrel (an Iranian-produced biosimilar of OCR) effectively inhibited EDSS progression, significantly reduced EDSS scores, and enhanced T25FW performance. In contrast, switching from RTX to Xacrel did not result in significant changes in mobility outcomes or disability status.