Use of Rituximab as an Off-Label Medication in Glomerular Diseases: Clinical Perspective

Abstract

<b><i>Objectives:</i></b> The aim of this study was to review the use rituximab (RTX) and outcomes in immune-mediated glomerular diseases (glomerulonephritis [GN]) and to compare it to the established literature. <b><i>Methods:</i></b> Adult GN patients who received RTX between January 2014 and January 2018 in three public hospitals were reviewed. Membranous nephropathy (MN) and minimal change disease (MCD) were considered diseases with the literature supporting RTX use. Lupus nephritis (LN), primary focal segmental glomerulosclerosis (1^o FSGS), IgA nephropathy, IgG4-related disease (IgG4-RD), and C3GN had insufficient literature support for RTX use. Clinical remission was assessed 6 months after receiving RTX. <b><i>Results:</i></b> A total of 61 cases were analyzed. RTX was an add-on therapy in 87%. The remission rate was 95% in the MCD and MN versus 56% in the off-label group (<i>p =</i> 0.002). LN patients had a mean initial estimated glomerular filtration rate (eGFR) of 69 mL/min. All class III LN achieved remission, and 11 of 21 class IV achieved remission. The mean initial eGFR for 1^o FSGS was 33 mL/min, and it did not improve, and only 2 of 5 had partial resolution of proteinuria. Proteinuria improved in 3 of 5 IgG4-RD cases with eGFR stabilization but failed to improve in C3GN cases with eGFR deterioration. Vasculitis cases (6 ANCA-associated vasculitis and 2 IgA vasculitis) were analyzed separately. Remission was achieved in only 2 ANCA-associated vasculitis cases, and none in IgA vasculitis cases. <b><i>Conclusions:</i></b> Our data support the use of RTX in resistant MCD and MN. RTX showed success in LN and IgG4-RD but not FSGS or C3GN. The small number of cases of vasculitis does not allow drawing a conclusion on RTX effectiveness.