Abstract: 【Abstract】 Objective To evaluate the efficacy and safety of telitacicept in the treatment of systemic lupus erythematosus （SLE）. Methods The clinical data of 25 SLE patients who received standard therapy combined with telitacicept at the Department of Dermatology, Xiangya Second Hospital, Central South University, from 2021 to 2024 were retrospectively collected. Baseline demographic and clinical characteristics were analyzed. Changes in skin lesions, joint pain symptoms, complete blood count, and biochemical parameters at 4, 12, and 24 weeks of treatment were compared with baseline （week 0）. The Wilcoxon signed-rank test was used to compare complement C3 and C4 levels before and after treatment, and univariate logistic regression analysis was performed to explore factors influencing the efficacy of telitacicept. Results Among the 25 SLE patients, 3 were male （12.0%） and 22 were female （88.0%）. Based on the SLE Disease Activity Index （SLEDAI）-2000 scores, 8 patients were mild, 13 were moderate, and 4 were severe. Of the 11 SLE patients with rashes before treatment, 6 achieved complete remission at 12 weeks. Among the 7 patients with joint pain before treatment, 4 experienced symptom resolution at 24 weeks. The proportion of patients with leukopenia at baseline and at 4, 12, and 24 weeks was 10/25 （40.0%）, 0/24 （0）, 1/22 （4.5%）, and 2/19 （10.5%）, respectively. The proportion of patients with thrombocytopenia was 6/25 （24.0%）, 3/24 （12.5%）, 1/22 （4.5%）, and 1/19 （5.3%）, respectively, and the proportion of patients with anemia was 7/25 （28.0%）, 3/24 （12.5%）, 1/22 （4.5%）, and 1/19 （5.3%）, respectively. At baseline, 11 out of 25 patients （44.0%） had proteinuria. At 12 weeks, the urinary protein quantification level （0.4 ［0, 0.6］ g/L） was significantly lower than at baseline （0.9 ［0.8, 1.2］ g/L）. The SLE responder index-4 （SRI4） response rates at 4, 12, and 24 weeks were 14/18, 15/17, and 12/14, respectively. Complement C3 and C4 levels were significantly higher at 4, 12, and 24 weeks compared to baseline （all P < 0.001）. Univariate logistic regression analysis showed that age, disease duration, glucocorticoid dosage, baseline complement C4 levels, antinuclear antibody titer, and SLEDAI-2K score did not significantly affect the efficacy of telitacicept （SRI4 response rate at 12 weeks） （all P > 0.05）. No serious adverse reactions related to telitacicept were observed in patients. Conclusions Telitacicept improved skin lesions, complement C3 and C4 levels, and anti-double-stranded DNA antibody levels in SLE patients. No association was found between the efficacy of telitacicept and baseline SLEDAI-2K scores, antinuclear antibody titers, or complement C4 levels, suggesting that telitacicept is an effective and safe treatment for SLE patients.

Key words: Lupus erythematosus, systemic, Biological agents, Treatment outcome, Drug-related side effects and adverse reactions, Telitacicept