Objective
Studies have shown that the efficacy of rituximab (RTX) in patients with M-type phospholipase A2 receptor (PLA2R)-associated primary membranous nephropathy (PMN) is related to proteinuria. However, definitive evidence to guide the initiation of RTX therapy based on proteinuria excretion levels in PMN is still lacking.
Methods
A total of 123 patients with PMN, confirmed by positive PLA2R staining in renal biopsy and/or serum anti-PLA2R antibody positivity, were enrolled in this study. All patients received RTX therapy. The patients were categorized into two groups based on their baseline proteinuria: 4-6 g and >6 g. Compared the outcomes and adverse events of patients between different groups after 12-month follow-up.
Results
This study revealed statistically significant differences in composite and complete remission rates after 12-month follow-up among PMN patients with different baseline proteinuria levels following RTX treatment. At 12-month follow-up, we found that the partial remission (PR) rate in the 4-6 g group was significantly higher than that in the >6 g group at the 1st and 3rd months (p = 0.002, p < 0.001), the complete remission (CR) rate in the 4-6 g group was significantly higher than that in the >6 g group at the 9th and 12th months (p = 0.024, p = 0.013), the composite response rate in the 4-6 g group was also significantly higher than that in the >6 g group at the 1st, 3rd, and 9th months (p = 0.003, p = 0.002, p = 0.037). Moreover, ROC curve analysis found that the predictive cutoff values for proteinuria determined by the Youden index were 4 g/d and 12 g/d, suggesting that the higher baseline proteinuria level was associated with a poorer therapeutic response.
Conclusions
Our findings show that lower baseline proteinuria was associated with a better response to RTX in PLA2R-associated PMN patients, whereas higher baseline proteinuria, particularly >12 g/day, was associated with lower remission rates.