Background/Purpose: The purpose of this study was to report the experience of a tertiary-care children’s hospital using rituximab in the treatment of pediatric antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), including immediate and long-term outcomes as well as adverse effects.

Methods: This was a single-center retrospective case series of 15 children with AAV treated with rituximab between March 2001 and March 2011. The majority of patients presented with severe disease, including acute pulmonary hemorrhage, and were treated with cyclophosphamide (CYC) and high-dose glucocorticoids (GC) concomitantly with rituximab (n=11); of these patients, six also required plasma exchange. Other treatment regimens given with rituximab included CYC alone (n=1), methotrexate (MTX) with GC (n=2) and MTX alone (n=1). Outcome measures included time to negative ANCA, the length of CYC therapy after starting rituximab, total cumulative CYC dose, scores on the modified Birmingham Vasculitis Activity Score for Wegener’s Granulomatosis (BVAS/WG) as well as the Vasculitis Damage Index (VDI).

Results: Of the 15 identified patients, the median age at diagnosis was 13 (range 8-15). Seven were female. At the time of treatment with rituximab, the mean score on the BVAS/WG was 7.8 (range 1-12), with 11 patients (73%) classified as having severe disease. Three months after treatment with rituximab, the mean score dropped to 0.4 (range 0-2). Every one of the patients in this series ultimately achieved remission, defined as a BVAS/WG of zero along with a reduction in steroid dosage. Nine patients (60%) received only one course of rituximab and did not experience any relapses over a mean follow-up of 2.3 years. Following treatment with rituximab, the mean duration of CYC therapy was 11.3 weeks (range 4-28 weeks), with a mean cumulative CYC dose of 11g.  The mean cumulative CYC dose received by patients who were initially treated without rituximab was 44 g prior to the addition of rituximab and was 62 g over the entire duration of illness captured by this study. In contrast, the cumulative CYC dose received by patients who received rituximab with CYC and GC for initial induction was only 8.6 g. The average length of patient follow-up after treatment with rituximab was 2.5 years (range 3 months – 5.1 years); during this time, five patients were re-treated with rituximab due to a flare in disease activity occurring at a mean of 21.8 months after the last rituximab treatment. Adverse effects from rituximab included six mild infusion reactions. There were no deaths. There were no documented infectious complications.

Conclusion: This is the largest described series of pediatric patients with AAV treated with rituximab and includes a significant duration of follow-up. Our data show that rituximab can be a safe and effective therapy, even in combination with other immunosuppressive medications such as CYC and GC. This regimen allows patients to have decreased cumulative dose of CYC, thus minimizing the potential for long-term adverse effects of CYC.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/rituximab-treatment-for-antineutrophil-cytoplasmic-antibody-associated-vasculitis-in-children/