Efficacy and safety of belimumab combined with the standard regimen in treating children with lupus nephritis

Purpose: To evaluate the efficacy and safety of belimumab combined with the standard regimen in treating children with active lupus nephritis. Methods: This was a single-center, retrospective cohort study. We collected the clinical data of children with newly active LN hospitalized in the Department of Nephrology between December 2004 and February 2023. The children were divided into belimumab and traditional treatment groups according to whether they received belimumab or not. The renal remission rate, recurrence rate, and glucocorticoid dose were compared between both groups. Results: 1) Baseline data of clinical and pathology: 47 children with a median age of 11 years were enrolled in this study, including 30 and 17 children in the traditional treatment and belimumab groups, respectively. The Systemic Lupus Erythematosus Disease Activity Index-2000 (SLEDAI-2000) score of children in the belimumab group (23.59 ±7.78) was higher than that for those in the traditional treatment group (19.13 ±6.10) ( t =2.176, P =0.035). The two groups showed no significant difference in pyuria, gross hematuria, 24-h urinary protein, and estimated glomerular filtration rate. In all cases, acute glomerulonephritis (34.0%) and nephrotic syndrome (48.9%) were the most common, and there were no differences in the clinical classification between both groups (χ2=2.192, P =0.533). Forty-two children completed renal biopsy, and there were no differences in the distribution of pathological classification and the activity and chronic indices between both groups ( χ ² = 4.441, P =0.35; t = 0.935, P = 0.357; Z =1.244, P = 0.322). 2) Efficacy: The complement C3/C4 in the belimumab group was faster than that in the traditional treatment group 3, 6, and 12 months after treatment ( P <0.05). The average SLEDAI-2000 score showed no difference in both groups at 6 and 12 months ( P =0.799; P =0.132). There were no differences in the complete remission rate between both groups at 6 months and 12 months (χ2=1.631, P =0.442; χ2=0.094, P =0.759). The 1-year recurrence rate was 13.3% in the traditional treatment group, and there was no clinical recurrence in the belimumab group (χ2=1.061, P =0.303). Furthermore, 6 months after treatment, the glucocorticoid dose in the belimumab group (17.87 ±6.96 mg/d) was significantly lower than that in the traditional treatment group (27.33 ±8.40 mg/d) ( P =0.000). At 12 months of treatment, the glucocorticoid dose in the belimumab group [10.00 (5.3) mg/d] was also significantly lower than that in the traditional treatment group [13.75 (10.0) mg/d] ( p =0.007). 3) Safety: there was no infusion reaction during belimumab treatment. Nine cases (52.9%) had two to four episodes of acute upper respiratory tract infections, one (5.9%) had gastroenteritis, one (5.9%) had tinea versicolor, and one (5.9%) had a varicella-zoster virus infection. The infection was relieved within 1 week without serious adverse reactions. During belimumab therapy, the levels of serum immunoglobulin M (IgM), IgG, and IgA showed a decreasing trend at 6 and 12 months compared with baseline, but there was no statistically significant difference ( P >0.5). Conclusion: With an equivalent renal remission rate, belimumab combined with the standard traditional regimen can reduce the dosage of glucocorticoids. The incidence of adverse events is low and generally in control.