Abstract
BACKGROUND: Anti-CD20 monoclonal antibody has become the first-line treatment option for primary membranous nephropathy (PMN), regardless of PLA2R status. Obinutuzumab (OBZ), a humanized anti-CD20 monoclonal antibody, has shown higher remission rates with an acceptable safety profile over rituximab (RTX), whether in the initial treatment or refractory PLA2R-associated membranous nephropathy. However, the efficacy evaluation of the OBZ and RTX in PLA2R-negative PMN has not been reported yet. METHODS: 39 patients with PMN who were negative for serum anti-PLA2R antibodies and showed negative PLA2R staining in renal biopsy were retrospectively included in this study, with 18 receiving OBZ and 21 receiving RTX. All patients received a 12-month follow-up. The primary outcome was the rate of patients achieving complete or partial remission (CR or PR) at 12 months. Secondary outcomes included changes in laboratory parameters, relapse, and adverse events. RESULTS: At 12 months, CR or PR was achieved in 17 of 18 (94.4%) patients in the OBZ group and 18 of 21 (85.7%) patients in the RTX group, with the difference between the two groups not being statistically significant (OR=2.83, 95% CI: 0.27-29.96; p=0.61). Kaplan-Meier analyses showed that the cumulative CR or PR rates were not significantly different (Log-Rank p=0.68). Adverse events occurred in 4 cases (22.2%) in the OBZ group and 6 cases (28.6%) in the RTX group. During the 12-momth follow-up, no relapse was observed in the OBZ group, whereas post remission relapse occurred in 2 (9.5%) of 21 patients in the RTX group (p=0.49). CONCLUSION: In patients with PLA2R-negative PMN, OBZ demonstrated similar efficacy to RTX, and both had a favorable safety profile.