Immunosuppressive Therapy in Primary Membranous Nephropathy with Compromised Renal Function

Abstract

Introduction: Renal dysfunction at presentation is uncommon in primary membranous nephropathy (PMN). The data on the outcome of PMN patients with renal dysfunction at outset are scarce. The objective of the current study was to report the clinical outcomes of PMN patients with renal dysfunction.

Material and methods: This prospective longitudinal observational study included PMN patients (both incident and treatment resistant) with an estimated glomerular filtration rate of <60 mL/min/1.73 m2. Immunosuppressive treatment was as per the unit's protocol. Patients were evaluated for proteinuria, creatinine, and serum albumin at monthly intervals for 6 months, then quarterly for a year, and then biannually. Both serum and tissue anti-PLA2R were performed at baseline.

Outcome: Percentage of patients achieving clinical remission.

Results: Sixty-four adults met study criteria and were analysed. The median (IQR) age of the patients was 48 (40, 56) years. PMN was PLA2R related in 52 (81.3%) patients. Twenty-eight (43.8%) and 30 (46.9%) patients were in remission at 12 months and at the end of the study [median (IQR) follow up: 24 months (12, 35)], respectively. Eight (12.5%) had progressed to end-stage renal disease at the last follow-up. Median (IQR) baseline anti-PLA2R titre was 150.1 RU/mL (38.5, 308). Nineteen (61.3%) and 18 (58.1%) patients with >90% reduction in anti-PLA2R titres at 12 months were in clinical remission at 12 months and at the end of the follow-up, respectively. Both cyclical cyclophosphamide/steroids (cCYC/GC) and rituximab were equally effective in inducing remission, but rituximab had a favourable adverse event profile compared to cCYC/GC.

Conclusion: To conclude, both cCYC/GC and rituximab are equally effective in inducing remission of nephrotic state with compromised renal function due to PMN. Immunosuppression induces remission in up to 50% PMN patients with CKD-stage 3-4.

Keywords: Estimated glomerular filtration rate; PLA2R; Primary membranous nephropathy; Renal dysfunction; Rituximab.