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Optimizing Rituximab Maintenance Therapy: Outcomes of Extended-Interval Dosing in Multiple Sclerosis and
Supawit Kittipadakul1, Tatchaporn Ongphichetmetha2,3, Sasitorn Siritho2,4
1Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
Journal of Clinical Medicine Research
|June 22, 2026
Summary
Rituximab (RTX) with extended dosing intervals guided by CD19 B-cell counts effectively controls relapses and improves disability in multiple sclerosis (MS) and NMOSD. This approach offers a potentially safer and more cost-effective treatment option for resource-limited settings.
Area of Science:
- Neuroimmunology
- Pharmacology
Background:
- Limited access to MS and NMOSD therapies in low-resource settings.
- Rituximab (RTX) offers an affordable off-label alternative but raises concerns regarding long-term adverse effects like hypogammaglobulinemia and infection.
- Extending RTX dosing intervals based on CD19 B-cell counts is a proposed strategy to balance efficacy, safety, and cost.
Purpose of the Study:
- To retrospectively assess the long-term efficacy and safety of RTX with CD19-guided, extended dosing intervals.
- To evaluate RTX's impact on relapse rates, disability scores, and adverse events in patients with MS and NMOSD.
- To explore the correlation between CD19 B-cell counts, dosing intervals, and treatment outcomes.
Main Methods:
- Retrospective analysis of clinical data from patients treated with RTX for at least 2 years at Siriraj Hospital, Thailand.
- Inclusion of patients with MS and aquaporin-4 immunoglobulin G-positive NMOSD.
- Extraction of data on clinical outcomes, CD19 lymphocyte counts, immunoglobulin levels, and imaging findings.
Main Results:
- Eighty-seven patients (43 MS, 44 NMOSD) were included, with mean RTX treatment durations of 4.10 and 4.92 years, respectively.
- RTX significantly reduced annualized relapse rates to 0.00 in both MS and NMOSD cohorts (P < 0.001).
- Median Expanded Disability Status Scale scores improved in both MS (2.0 to 0.0, P = 0.006) and NMOSD (4.5 to 4.0, P < 0.001).
- Adverse events included infusion reactions and infections; hypogammaglobulinemia occurred in 6.7% of NMOSD patients, with no fatal events.
- Four patients on intervals >48 weeks remained relapse-free with <1% CD19+ B-cells.
Conclusions:
- CD19-guided, extended-interval RTX demonstrates efficacy in relapse control and disability improvement for MS and NMOSD.
- This dosing strategy offers favorable tolerability, potentially reducing infusion frequency and healthcare costs in resource-constrained environments.
- Vigilance for CD19-positive B-cell repopulation during extended intervals is crucial as it may indicate an increased relapse risk.
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