Background: Biannual rituximab infusions over 18 months effectively maintain remission after a "standard" remission induction regimen for patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV).
Objective: To evaluate the efficacy of prolonged rituximab therapy in preventing AAV relapses in patients with granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA) who have achieved complete remission after completing an 18-month maintenance regimen.
Design: Randomized controlled trial. (ClinicalTrials.gov: NCT02433522).
Setting: 39 clinical centers in France.
Patients: 68 patients with GPA and 29 with MPA who achieved complete remission after the first phase of maintenance therapy.
Intervention: Rituximab or placebo infusion every 6 months for 18 months (4 infusions).
Measurements: The primary end point was relapse-free survival at month 28. Relapse was defined as new or reappearing symptoms or worsening disease, with a Birmingham Vasculitis Activity Score greater than 0.
Results: From March 2015 to April 2016, 97 patients (mean age, 63.9 years; 35% women) were randomly assigned, 50 to the rituximab and 47 to the placebo group. Relapse-free survival estimates at month 28 were 96% (95% CI, 91% to 100%) and 74% (CI, 63% to 88%) in the rituximab and placebo groups, respectively, an absolute difference of 22% (CI, 9% to 36%) with a hazard ratio of 7.5 (CI, 1.67 to 33.7) (P = 0.008). Major relapse-free survival estimates at month 28 were 100% (CI, 93% to 100%) versus 87% (CI, 78% to 97%) (P = 0.009), respectively. At least 1 serious adverse event developed in 12 patients (24%) in the rituximab group (with 9 infectious serious adverse events occurring among 6 patients [12%]) versus 14 patients (30%) in the placebo group (with 6 infectious serious adverse events developing among 4 patients [9%]). No deaths occurred in either group.
Limitation: Potential selection bias based on previous rituximab response and tolerance.
Conclusion: Extended therapy with biannual rituximab infusions over 18 months was associated with a lower incidence of AAV relapse compared with standard maintenance therapy.
Primary funding source: French Ministry of Health and Hoffmann-La Roche.