Rituximab maintenance therapy for granulomatosis with polyangiitis and microscopic polyangiitis.

OBJECTIVE: To evaluate the efficacy compared to the relapse risk and tolerance of systematic rituximab (RTX) infusions as maintenance therapy for patients with granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA), who entered remission taking conventional immunosuppressants or RTX.
METHODS: A retrospective study of the main clinical characteristics, outcomes, and RTX tolerance of patients who had received ≥ 2 RTX maintenance infusions in our center, regardless of induction regimen, between 2003 and 2010.
RESULTS: We identified 28 patients [4 MPA and 24 GPA; median age 55.5 yrs (range 18-78); 17 (60%) males] who received a median of 4 (range 2-10) RTX maintenance infusions, with median followup of 38 months (range 21-97) since diagnosis or last flare. None experienced a RTX infusion-related adverse event; 15 patients (among the 21 with available data) had hypogammaglobulinemia (predominantly IgM) prior to their last RTX maintenance infusion; 3 had infectious events (1 cutaneous abscess, 1 otitis, 1 fatal H1N1 flu). Two patients suffered pulmonary relapses shortly before a planned RTX maintenance infusion (both had increased antineutrophil cytoplasmic antibody levels and 1 had CD19+ lymphocyte reconstitution).
CONCLUSION: Rituximab maintenance therapy was well tolerated but did not completely prevent relapses and persistent "grumbling" disease. These preliminary results remain to be confirmed by a randomized controlled trial currently in progress.