Non-inferiority of Rituximab versus OCrelizumab in Multiple Sclerosis (ROC-MS)—an individual participant data meta-analysis

Background: Ocrelizumab (OCR) is widely and effectively used to treat multiple sclerosis (MS). Available evidence suggests that rituximab (RTX), another anti-CD20 monoclonal antibody used off-label in some countries, may be equally effective and safe. However, current data comparing RTX and OCR come from retrospective observational cohorts with conflicting conclusions. Higher-quality evidence is needed to guide treatment decisions when choosing between RTX and OCR for MS. To address this high priority research question, four randomized controlled trials (OVERLORD-MS, DanNORMS, Noisy Rebels, TRIO) are evaluating the non-inferiority of RTX compared to OCR and have formed a collaborative initiative (ROC-MS) to conduct an individual participant data (IPD) prospective meta-analysis (PMA). Methods: In the PMA, core outcomes are harmonized across the four trials. IPD will be obtained from active relapsing-remitting MS (RRMS) patients. Primary outcome is relapse in a re-baselined period from month 6 to month 24 and a non-inferiority hypothesis will be tested. Secondary outcomes include other clinical, patient-reported, radiological, blood biomarkers, and safety measures. Collectively, the studies in the collaboration will provide data from 1109 RRMS patients: 660 receiving RTX and 449 receiving OCR. Patient recruitment has started at all sites and has been completed at two sites, as of October 2025. Conclusion: This ROC-MS collaboration will improve the precision of the estimates, increase statistical power for outcomes and assessment of rare events and facilitate subgroup analyses, ultimately providing robust evidence on the efficacy and safety of RTX compared to OCR in RRMS treatment. Results are expected in 2028.