[Short-term efficacy of rituximab in children with calcineurin inhibitor resistant steroid resistant nephrotic syndrome].

Objective: To investigate the short-term efficacy and safety of rituximab (RTX) in children with calcineurin inhibitor (CNI) resistant steroid resistant nephrotic syndrome (SRNS). Methods: A retrospective case analysis was conducted. Thirteen children with CNI resistant SRNS who were regularly treated with RTX (375 mg/m2 per dose (maximum dose 500 mg), 1 dose per week, a total of 4 doses) in Department of Nephrology, Children's Hospital of Fudan University from January 2016 to December 2023 were enrolled. The general data, disease related information, urinary protein/creatinine, serum albumin, blood creatinine before RTX treatment, immunosuppressants, adverse events, and monthly urinary protein/creatinine, serum albumin, and blood creatinine indexes within 6 months after RTX treatment were collected. The changes of urinary protein/creatinine, serum albumin and estimated glomerular filtration rate (eGFR) before and after RTX at 3 and 6 months were analyzed by using paired sample t test and Wilcoxon signed-rank test. Results: Among the 13 patients, 8 were male and 5 were female. The age of disease onset was 4.0 (2.9, 6.8) years and the age of RTX treatment was 9.8 (5.9, 13.6) years. There were 8 cases of focal segmental glomerulosclerosis, 3 cases of minimal change disease and 2 cases of mesangial proliferative glomerulonephritis. No clinically significant gene variation was detected in 12 cases and the other one did not receive gene test. Before RTX treatment, 11 cases were in chronic kidney disease stage G1, and 1 case each was in stage G2 and stage G3. Ten children completed 4 doses of RTX treatment, 1 patient completed 3 doses, and 2 patients completed 2 doses. Urinary protein/creatinine in 13 children at 3 and 6 months after RTX treatment was significantly lower than baseline (0.60 (0.13, 2.04), 0.49 (0.28, 1.10) vs. 1.44 (0.76, 4.11) mg/mg, Z=-2.34, -2.34, both P<0.05), and serum albumin was significantly higher than baseline ((35±8), (34±7) vs. (30±6) g/L, t=2.30, 2.60, both P<0.05). The eGFR at 6 months after RTX treatment was not significantly different from the baseline ((110±32) vs. (113±35) ml/(min·1.73 m2),t=-0.76,P>0.05)). No serious adverse reactions occurred in this study. Conclusion: RTX could reduce urinary protein and increase serum albumin in short-term treatment in children with CNI resistant SRNS without significant side effects.