#1283 Rituximab in addition to plasma exchange, cyclophosphamide and steroids for treatment of anti-GBM disease

Abstract

Abstract Background and Aims Anti-GBM disease is a rare antibody-mediated vasculitis, usually treated with plasma exchange (PEX), cyclophosphamide (CYC) and steroids. There are limited data regarding the use of B-cell depleting therapies such as rituximab (RTX). We investigate the use of the addition of rituximab for the treatment of Anti-GBM disease. Method Ten-year (2012-2023) single-centre retrospective cohort study of patients with anti-GBM disease treated with or without rituximab, in addition to standard care, as first-line therapy. A Cox-proportional hazards regression model incorporating age, sex, ANCA status, dialysis need at presentation, lung haemorrhage, CYC (oral or IV) and RTX treatment was used to identify disease/treatment factors associated with outcome (death, end-stage kidney disease [ESKD], infection). Results Forty-five patients are included; baseline demographics, disease characteristics, treatments and outcomes are summarised in Table 1. In the Cox regression model, only increasing age was associated with risk of death (HR 1.08 [95% CI 1.02-1.17]). Age (HR 1.04 [1.01-1.08]), female sex (HR 4.93 [1.80-4.87]), and dialysis need at presentation (HR 5.28 [1.54-17.53]) were associated with ESKD-risk. Increasing age (HR 1.04 [1.00-1.09] and ANCA positivity (HR 3.08 [1.14-8.71]) were associated with risk of infection. The addition of rituximab was not significantly associated with risk of death (HR 0.82 (0.24-2.87), ESKD (HR 1.54 [0.64-3.96]) or infection 2.06 [0.67-5.71]. Conclusion Addition of rituximab to standard treatment for anti-GBM disease was not associated with improved renal outcome or survival benefit. However, rituximab use permitted lower cumulative doses of CYC and reduction in the number of PEX, without an increased risk of infection. Rituximab may have a role as a CYC- and PEX-sparing treatment in patients with anti-GBM disease.