Rituximab for non-responsive idiopathic membranous nephropathy in a Chinese cohort

Background. Rituximab had been shown to be effective in inducing remission of nephrotic syndrome in patients with idiopathic membranous nephropathy (iMN). This study applied rituximab therapy for 36 non-responsive iMN patients to investigate its effects and safety. Methods. Thirty-six iMN patients who were non-responsive to prior immunosuppression were enrolled. Rituximab was used for B-cell depletion in patients, with a goal of <5 B cells/mm(3) in the circulation. After completing the study, patients were monitored for a median of 12.0 months [interquartile range (IQR) 9.0-19.3]. Results. Fifteen of the 36 (41.7%) patients achieved partial (n = 13) or complete (n = 2) response to the rituximab treatment. The median time for achieving partial response was 4.0 months (IQR 3.0-6.0). The responders had relatively lower levels (118 +/- 112 U/mL versus 345 +/- 357 U/mL, P = 0.03) of anti-phospholipase 2 receptor (PLA2R) antibodies before the rituximab treatment, and all of them achieved antibody depletion or reduction. B-cell depletion was achieved in all patients. Renal function remained stable in the responders [estimated glomerular filtration rate (eGFR) 53.3 +/- 40.5 versus 55.6 +/- 33.2 mL/min/1.73 m(2), P = 0.67] but deteriorated in the non-responders (eGFR 57.5 +/- 293 versus 453 +/- 32.8 mL/min/1.73 m(2), P = 0.02) with two patients reaching end-stage kidney disease. Two of the 15 patients relapsed during the follow-up period with anti-PLA2R antibody reoccurrence and B-cell reconstitution. The second course of rituximab combined with tacrolimus induced a faster partial response again in one patient. Conclusion. Rituximab therapy could induce remission of proteinuria and stabilization of renal function in non-responsive iMN patients, even those with damaged renal function. Anti-PLA2R antibodies may be used as a marker for individualized rituximab dosage and treatment monitoring.