Rituximab for remission maintenance in relapsing antineutrophil cytoplasmic antibody-associated vasculitis

Objective. Rituximab is effective induction therapy in refractory or relapsing antineutrophil cytoplasmic antibodyassociated vasculitis (AAV). However, further relapse is common, and maintenance strategies are required. The aim of this study was to reduce relapse rates using a fixed-interval rituximab re-treatment protocol. Methods. Retrospective, standardized collection of data from sequential patients receiving rituximab for refractory or relapsing AAV at a single center was studied. Group A patients (n = 28) received rituximab induction therapy (4 infusions of 375 mg/m(2) or 2 infusions 1 gm) and further rituximab at the time of subsequent relapse. Group B patients (n = 45) received routine rituximab re-treatment for 2 years: 2 doses of 1 gm each for remission induction, then 1 gm every 6 months (total of 6 gm). Group C patients (n = 19) comprised patients in group A who subsequently relapsed and began routine re-treatment for 2 years. Results. Response (complete/partial remission) occurred in 26 of the 28 patients (93%) in group A, 43 of the 45 patients (96%) in group B, and 18 of the 19 patients (95%) in group C. At 2 years, relapses had occurred in 19 of 26 patients (73%) in group A, 5 of 43 (12%) in group B (P < 0.001), and 2 of 18 (11%) in group C (P < 0.001). At the last followup (median of 44 months), relapses had occurred in 85% of those in group A (22 of 26), 26% of those in group B (11 of 43; P < 0.001), and 56% of those in group C (10 of 18; P = 0.001). Glucocorticoid dosages were decreased and immunosuppression therapy was withdrawn in the majority of patients. Routine rituximab re-treatment was well tolerated, and no new safety issues were identified. Conclusion. Two-year, fixed-interval rituximab re-treatment was associated with a reduction in relapse rates during the re-treatment period and a more prolonged period of remission during subsequent followup. In the absence of biomarkers that accurately predict relapse, routine rituximab re-treatment may be an effective strategy for remission maintenance in patients with refractory and relapsing AAV.