Low Versus Standard Dose of Rituximab in Adult Patients with Relapsed or Refractory Primary Membranous Nephropathy: Does It Make Any Difference?

Objective: Optimal dose of rituximab is still under debate in patients with primary membranous nephropathy, particularly who suffer from relapsed or refractory disease. We, therefore, analyzed the efficacy of low versus standard doses of rituximab in these patients. Methods: Thirty-six consecutive patients with primary membranous nephropathy and characterized by proteinuria >= 3.5 g/24h despite at least 6 months of prior conservative and immunosuppressive therapy were included. Rituximab was administered in 2 different protocols: low dose (n = 20, 55.5%) (2 weekly doses of 375 mg/m(2)) and standard dose (n = 16, 44.4%) (4 weekly doses of 375 mg/m(2)). Primary outcome was defined as complete remission or partial remission. Results: One patient who died due to sepsis caused by pneumonia shortly after rituximab and 1 who developed anaphylaxis during his first infusion were excluded from efficacy analyses. Overall, 34 patients were followed up for a median duration of 15.5 (interquartile range: 6-23.25) months after treatment. Nineteen (55.8%) patients experienced primary outcomes; among these, 12/18 (66.6%) were in low-dose group as compared to 7/16 (43.75%) in standard dose. The percentage of patients who underwent remission was similar in 24-month Kaplan-Meier analysis (P =.393). Five patients (27.7%) in low-dose group had a relapse, whereas no patients in standard dose group relapsed throughout the follow-up (P =.022). Carcinoma of the tongue developed in a patient, and 2 patients died due to sepsis caused by pneumonia. Conclusion: Low and standard doses of rituximab showed similar efficacy in patients with relapsed or refractory primary membranous nephropathy, albeit lower doses were associated with more relapses.