To evaluate the noninferiority of rituximab compared to ocrelizumab in preventing new or enlarging T2-weighted MRI lesions in patients with newly diagnosed relapsing multiple sclerosis.
Approach:
Trial Design: Randomized, double-blind, multicenter, noninferiority trial conducted at 12 neurology departments in Norway and Sweden.
Participants: 218 participants aged 18 to 60 years with newly diagnosed relapsing MS were randomized in a 3:2 ratio to receive either rituximab or ocrelizumab.
Treatment Regimen: Rituximab 1000 mg at baseline followed by 500 mg every 6 months; ocrelizumab 600 mg at baseline and every 6 months.
Endpoints: Primary endpoint was absence of new or enlarging lesions on T2-weighted MRI from month 6 to month 24.
Key Findings:
Rituximab was noninferior to ocrelizumab regarding the primary endpoint, with 89% of rituximab and 93% of ocrelizumab participants showing no new or enlarging lesions.
Serious adverse events occurred at similar rates (8% for rituximab, 7% for ocrelizumab), but infections were more common with rituximab (82% vs 69%).
Estimated annualized relapse rates were 0.09 for rituximab and 0.04 for ocrelizumab, with 92% of participants receiving rituximab and 94% receiving ocrelizumab remaining relapse-free through 24 months.
Interpretation:
The trial did not establish superiority or equivalence between rituximab and ocrelizumab in preventing MRI lesions.
Limitations:
The trial was not powered to detect differences in secondary endpoints or rare safety outcomes.
Follow-up was limited to 30 months, and the study population may not be generalizable to patients with longer disease duration or previous treatment exposure.
Randomization implementation errors occurred at some sites.
Conclusion:
The trial results indicate the need for further studies to assess the comparative effectiveness of rituximab and ocrelizumab.
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