Sustained renal response with belimumab in children with new-onset lupus nephritis

BACKGROUND: Belimumab is approved for treating systemic lupus erythematosus (SLE) in children over 5 years old; however, its efficacy and safety in pediatric SLE patients require further validation. This study aimed to evaluate the impact of belimumab on the long-term cumulative probability of sustained renal response and disease flare in children with lupus nephritis (LN), to inform clinical decision-making. METHODS: We included a total of 96 children with LN in our study. The patients were part of a prospective cohort study and were divided into two groups: belimumab group (68 cases) and standard treatment (group (28 cases). We compared remission rates, flare rates, and adverse event incidence between these two groups. RESULTS: After 152 weeks of follow-up, belimumab increased the renal response and complete renal response rates by 16.7% [odds ratios (OR) = 5.38 (1.33, 15.12)] and 24.7% [OR = 2.74 (1.04, 7.19)]. Belimumab significantly reduced the risk of LN flare, with a 46.2% lower flare rate in the belimumab group compared to the standard treatment group. There was no significant difference in long-term cumulative probability of complete remission between the belimumab and standard treatment groups (P = 0.081), and the standard treatment group had a higher flare rate (P = 0.004). CONCLUSIONS: Adding belimumab to standard treatment may effectively maintain long-term kidney function and reduce LN flares, making it an effective and safe biologic agent.