Comparison of telitacicept and belimumab in systemic lupus erythematosus: a real-word retrospective study.

OBJECTIVES: Telitacicept and belimumab are two biological agents approved for treating systemic lupus erythematosus (SLE) in China. This study mainly discusses the therapeutic efficacy of these two biological agents in SLE. METHODS: SLE patients who received telitacicept or belimumab at Nanjing Drum Tower Hospital from March 2021 to March 2023 were included. Clinical characteristics were compared, and 1:1 propensity score matching (PSM) was performed. Statistical analyses included normality tests, t tests, Mann‒Whitney U tests, and chi‒square tests. RESULTS: Both telitacicept and belimumab demonstrated robust clinical efficacy. Pre-matching, SLE responder index-4 (SRI-4) response rates were 42.4% (telitacicept) and 49% (belimumab), with median SLEDAI reductions of 2 and 1.5 points, respectively. Serum albumin, complement component 3 (C3), and complement component 4 (C4) levels increased significantly after treatment in both groups. Post-matching, clinically meaningful SRI-4 rates persisted (40.0% vs. 52.0%, P = 0.570), alongside median SLEDAI reductions (10 to 8 vs. 12 to 8). After PSM, although overall bias was reduced, baseline imbalances persisted for key laboratory parameters, notably serum C4 (standardized mean difference [SMD] > 0.2), necessitating cautious interpretation of between-group comparisons. Although the median absolute C4 increase was numerically higher with telitacicept (0.07 [IQR 0.01-0.11]) than belimumab (0.03 [IQR 0.01-0.10]), effect size quantification revealed a small magnitude (Hedges' g = 0.243, 95% CI: - 0.319 to 0.804) with limited precision. Exploratory analysis of the lupus nephritis subgroup revealed a more pronounced reduction in IgG levels with telitacicept versus belimumab (nominal P = 0.019; Hedges' g =  - 0.242, 95% CI: - 0.755 to 0.272), though findings remain hypothesis-generating given the limited sample size and unadjusted multiple comparisons. CONCLUSION: Both telitacicept and belimumab reduced disease activity in SLE. While telitacicept exhibited a numerical trend toward greater C4 elevation in SLE and a potential signal of greater IgG reduction in LN, these findings require validation in adequately powered prospective trials. Key points • This study compared the efficacy of telitacicept and belimumab treatment in SLE, presenting important reference function for clinical medication.