Obinutuzumab in the Treatment of Primary Membranous Nephropathy: Case Series and Literature Review

Membranous nephropathy (MN) is a major autoimmune cause of adult primary nephrotic syndrome. Its hallmark pathological feature is the deposition of immune complexes on the subepithelial side of the glomerular basement membrane. Although rituximab(RTX), a well-established targeted biologic agent, is widely used and achieves remission in 60–80% of patients with primary membranous nephropathy (PMN), a subset of patients fails to achieve remission after months of follow-up despite a full-course regimen. These non-responders are classified as having RTX-refractory PMN. This study evaluated the efficacy and safety of obinutuzumab (OBZ) in 11 patients with RTX-refractory PMN. Data from patients with complete follow-up records at the Second Affiliated Hospital of Anhui Medical University (January 2023 to July 2025) were analyzed. Patient characteristics and laboratory parameters were documented, and statistical analyses were performed using SPSS 22.0. The results indicated that 10 patients (90.9%) achieved remission following OBZ treatment, comprising 6 (54.5%) with a partial response and 4 (36.4%) with a complete response. The median time to response was 3.5 months (IQR 1.5–7.75). One patient (9.1%) showed no response. Treatment-related adverse events were mild to moderate and occurred in 3 patients (27.3%), with no severe events reported. OBZ demonstrates promising efficacy and a acceptable safety profile in RTX-refractory PMN, although larger prospective studies with longer follow-up are required for confirmation.