Rituximab for the treatment of Churg-Strauss syndrome with renal involvement

Introduction. Churg-Strauss syndrome (CSS) is a small vessel systemic vasculitis associated with asthma and eosinophilia that causes glomerulonephritis (GN) in similar to 25% of patients. Rituximab (RTX) is a chimeric anti-CD20 monoclonal antibody that depletes B cells and is effective in numerous autoimmune diseases including antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. We aim to evaluate the safety and efficacy of RTX in inducing remission of renal disease activity in patients with CSS. Methods. We conducted a single-center, open-label pilot study using RTX (375 mg/m(2)/week 3 4) for induction of remission in CSS patients with renal involvement [defined as having > 25% dysmorphic red cells, red blood cell casts or pauci-immune GN on biopsy]. Written informed consent was obtained from all individuals. Patients were eligible if they were untreated, had failed glucocorticoid therapy or had failed glucocorticoid dose reductions because of disease relapses. The primary outcome was remission of renal disease activity defined as stability or improvement of creatinine clearance, absence of active urinary sediment and reduction of the glucocorticoid dose to < 50% of the average dose received over 3 months before enrollment or < 10 mg/day (whichever is smaller) at 6 months. Patients were followed up for 1 year. Results. Only three patients (two females; ages 54, 55 and 65) were enrolled. All patients had positive myeloperoxidase-ANCA and renal involvement. Two patients had biopsyproven pauci-immune crescentic GN. All achieved the primary end point of renal remission within the first 3 months and remained in renal remission during the year following RTX treatment. One patient experienced a non-renal relapse (eye and joint involvement) at 6 months coinciding with the reconstitution of CD191 cells and eosinophilia. He was retreated with RTX and achieved remission within 6 weeks. No major adverse effects were recorded. Conclusions. In this pilot study, RTX was safe and successful in controlling renal disease activity in three patients with CSS. This agent deserves further study in CSS.