#3108 Rituximab in adult-onset IgA vasculitis

Abstract

Abstract Background and Aims Adult-onset IgA Vasculitis (IgAV) is poorly responsive to glucocorticoids (GC) and conventional immunosuppressive therapies, such as cyclophosphamide. Rituximab has been successfully used in a few cases and may represent a safer and potentially more effective option [1]. Crescentic IgA Nephropathy (cIgAN), a rare entity that shares features of renal vasculitis with IgAV, is also frequently refractory to cyclophosphamide, while response to rituximab is unknown. We investigated outcomes after rituximab in a multicentre European cohort of adult-onset IgAV and cIgAN. Method We screened clinical records of patients followed at 18 European consorted centres who were ≥18 years old at the onset of IgAV and received ≥1 rituximab dose. Furthermore, we identified patients with cIgAN (≥25% crescentic glomeruli and rapidly progressive glomerulonephritis), who were treated with rituximab. Remission was defined as Birmingham Vasculitis Activity Score (BVAS) <3 at month 6 after rituximab and renal response as stable or improved eGFR and ≥50% proteinuria reduction. Relapse was defined as an increase in BVAS requiring a change in immunosuppressive therapy. Outcomes of IgAV with severe nephritis (eGFR <60 mL/min) were compared with those of cIgAN. Results We included 61 patients with IgAV and 15 with cIgAN (Table). Rituximab was administered as initial therapy in 23/61 (38%) patients with IgAV and 13/15 with cIgAN (87%), while the remainder had refractory or relapsing disease. Active skin involvement was present in 49 patients (80%) and nephritis in 55 patients (90%) with IgAV at the time of starting rituximab. This was given alone in 13/61 (21%) or combined with GC in 48 (79%) patients with IgAV and in all those with cIgAN. Furthermore, cyclophosphamide was used in 15% of patients with IgAV and 40% of those with cIgAN. Remission at 6 months was achieved by 52 (85%) patients with IgAV and 12/13 (92%) of those treated with rituximab alone. A renal response was observed among 49/55 (89%) of those with nephritis. Patients with IgAV and severe nephritis had similar eGFR to those with cIgAN at the time of starting rituximab, but the latter had lower rate of remission and a higher frequency of kidney failure. A relapse occurred in 15/52 patients (29%) who achieved remission a median of 13 months (10-15) after rituximab. Eight patients resumed rituximab and achieved again remission. Conclusion Rituximab alone or in combination with GC and immunosuppressants appeared to achieve a high rate of remission in this cohort of adult-onset IgAV. Renal response among those with severe nephritis was also good, while this was worse among patients with cIgAN, suggesting substantial differences among these conditions despite similar histological appearances.