#600 The efficacy and safety of ripertamab in inducing remission of primary membranous nephropathy: a retrospective study

Abstract Background and Aims Ripertamab composed of 70% human IgG1 constant region Fc fragments targeting CD20. Compared to rituximab, ripertamab minimize the immunogenicity of the drug while preserving its therapeutic efficacy. This study aims to investigate the efficacy and safety of ripertamab in inducing remission of PMN in adults. Method This retrospective study included 13 patients diagnosed with PMN via renal biopsy or positive serum PLA2R antibodies between February 1, 2023 and November 31, 2023. Patients were classified into PLA2R-positive (n = 9) and PLA2R-negative(n = 4) groups. All patients received ripertamab (375 mg/m² weekly for 4 doses or 1 g biweekly for 2 doses) with a follow-up period of 6 months. Primary outcomes included remission rates, changes in renal function, anti-PLA2R antibody levels, and B-cell depletion. Complete remission (CR) was defined as 24-hour proteinuria <0.3 g, serum albumin >35 g/L, and stable renal function. Partial remission (PR) was defined as a ≥ 50% reduction in proteinuria with serum albumin >30 g/L. Kaplan-Meier were used to compare differences in prognosis. Results After 6 months, 69.23% patients achieved remission (CR: 38.46%, PR: 30.77%). PLA2R-negative patients exhibited a higher rate of composite remission (100%) compared to PLA2R-positive patients (55.56%). Among the PLA2R-positive group, 7 of 9 showed reductions in anti-PLA2R antibody levels, with 5 achieving seroconversion. All patients demonstrated significant improvements in renal function, with B-cell depletion was achieved. No adverse events were observed during the study. Conclusion This study suggests that ripertamab could be an effective and safe treatment for PMN.