Low-dose Rituximab therapy in resistant idiopathic membranous nephropathy: single-center experience

BACKGROUND: Persistent significant proteinuria has been associated with increased risk of progression to end-stage kidney disease in patients with idiopathic membranous nephropathy (IMN). Rituximab (RTX) therapy has given encouraging results in IMN, but most of the studies have used a higher dose, which is limited by the high cost as well as a potential increased risk of infections. Our study aimed to assess the efficacy and safety of low-dose RTX in patients with immunosuppression-resistant IMN. METHODS: A total of 21 patients with treatment-resistant IMN treated with RTX from 2015 to 2016 at our center were included in the study. They received two doses of RTX (500 mg each) infusion 7 days apart. CD19 count was performed after 4 weeks. A single dose of RTX was repeated after 4–6 weeks if CD19 count was not depleted. RESULTS: The mean standard deviation age of patients was 33.3 ± 12.3 years and 33.3% were females. Mean proteinuria before RTX therapy was 6.2 ± 2.2 g/day, serum creatinine was 0.9 ± 0.3 mg/dL and estimated glomerular filtration rate (eGFR) was 95.8 ± 26.9 mL/min/1.73 m(2). All the patients were non-responders to prior immunosuppressive treatment. Twenty (95.2%) patients achieved targeted CD19 depletion with two doses of RTX. One patient required one additional RTX dose due to inadequate B-cell suppression. A total of 13 (61.9%) patients achieved remission with RTX therapy: 4 (19.0%) complete and 9 (42.9%) partial remission. Patients who did not respond to RTX had a significantly lower baseline eGFR compared with those who achieved remission (P = 0.022). One patient developed respiratory tract infection following RTX during the follow-up, which responded to a course of oral antibiotics. During median follow-up of 13.1 (10–23.9) months, four (19%) patients had deterioration in renal function and one patient relapsed after achieving partial remission. Renal survival was significantly better in patients who responded to RTX therapy as compared with those who did not achieve remission (P = 0.0037). CONCLUSION: Low-dose RTX therapy is effective and safe in immunosuppression-resistant IMN.