Off-Label Use of Rituximab in Patients with Different Types of Nephropathies in a Tertiary Hospital: A Retrospective Study

Off-label use of rituximab is commonly requested for patients with resistant nephropathies. The outcomes and tolerability of rituximab in adult patients with nephropathy treated at our hospital (from 2013 to 2018) were described. Data were retrieved from electronic medical records. Response was classified as complete remission (CR), partial remission (PR), or no response (NR) according to the KDIGO criteria. A total of 89 requests were received for 61 patients. Median age was 58 years (45.9% female). Idiopathic membranous nephropathy (MN) (n = 30) was the most frequent indication, followed by minimal change disease (MCD) (n = 15) and secondary membranoproliferative glomerulonephritis (MPGN) (n = 12). Three patients with focal segmental glomerulosclerosis (FSGS) were included. After most treatment cycles in MN, a CR or PR was observed; median proteinuria levels significantly decreased for these patients (6000 mg/24h (IQR 3584–10,300) vs. 1468.8 (IQR 500–4604.25), p < 0.01). In MPGN, no response was documented after 46.7% of rituximab cycles. A CR or PR was described with the majority of rituximab cycles in MCD, with a significant decrease in proteinuria (6000 mg/24 h (IQR 4007–11,426) vs. 196.8 (IQR 100–1300), p = 0.013). No cycles produced a response in FSGS. Mean CD19+ B-cell decreased in all types of nephropathy (10.44% vs. 0.29%, p < 0.0001). Eleven patients presented infusion-related reactions, and 17 presented infectious complications. The majority of patients with MN and MCD had complete or partial responses; however, neither MPGN nor FSGS had encouraging results.