#3243 Remission rates of immunotherapy with anti-CD20 monoclonal antibody (rituximab) in patients with membranous nephropathy

Abstract Background and Aims Long-term remission of albuminuria in patients with membranous nephropathy is the main therapeutic goal, contributing to the preservation of renal function. The aim of the present study was to investigate the efficacy and safety of monoclonal anti CD20 antibody administration in patients with membranous nephropathy, depending on serum anti-PLA2R titer at diagnosis. Method The effect of treatment with monoclonal anti CD20 antibody (rituximab) in two doses of 1 g at 2 weeks interval was studied retrospectively in patients with histologically documented membranous nephropathy. Serum anti-PLA2R titer was measured at diagnosis. Rituximab was given either as treatment after relapse of nephrotic syndrome, or upon failure of the first immunosuppressive regimen (failure to achieve remission), or as first-line therapy. All patients were followed up for at least one year after administration. Results A total of 21 patients (19 men) with a mean age of 58.3 ± 10.7 years were studied. Thirteen participants (62%) had positive serum anti-PLA2R titer at diagnosis, while 8 patients (38%) had negative titer. Patients who received Rituximab maintained their kidney function with a mean eGFR from 81.2 ± 27.9 to 80 ± 24.8 ml/min/1.73 m² at the end of one year follow up, while proteinuria decreased from 7.5 ± 5.7 to 3.0 ± 2.9 gr/24h regardless of anti-PLA2R titer. Eight patients (5 anti-PLA2R positive) had complete remission, 6 patients (3 anti-PLA2R positive) had partial remission, while 7 patients (5 anti-PLA2R positive) did not respond to treatment. Further analysis according to serum anti-PLA2R titer showed that patients with negative anti-PLA2R titer (n = 8) had a greater reduction in albuminuria at 12 months compared to patients with positive anti-PLA2R titer (n = 13) (from 9.4 ± 8.8 to 2.4 ± 2.5 gr/24 h and from 6.3 ± 2.1 to 3.1 ± 3.2 gr/24 h, respectively), although the difference in proteinuria reduction at 12 months between the two groups was not significant (P = 0.176). Conclusion Treatment with Rituximab in patients with membranous nephropathy achieves preservation of renal function during the follow-up period and partial or complete remission of proteinura regardless of serum anti-PLA2R titer.