Pos0534 Efficacy of Telitacicept in the Treatment of Lupus Nephritis: A 52-Week, Multicenter Observational Study

Background: The past decade has witnessed the innovation of several biologics and small molecules, most of which target B cells, including B-cell activating factor/a proliferation-inducing ligand (BAFF/APRIL) inhibitors, in the treatment of Systemic lupus erythematosus (SLE). Telitacicept is a TACI-immunoglobulin fusion protein that neutralizes the activity of both BAFF and APRIL by competitively inhibiting the TACI site, thereby suppressing the development and survival of plasma cells and mature B cells. Although randomized trials have demonstrated that telitacicept are effective for patients who have SLE with active disease in a phase IIb study 1, the efficacy in lupus nephritis (LN) has not been investigated in real-world clinical practice. Objectives: To investigate the efficacy of dual BAFF/APRIL inhibitor telitacicept as an add-on therapy in the treatment of LN in real clinical practice. Methods: Fifty-one patients who was diagnosed as LN and received telitacicept for 52 weeks from 2019 to 2023 at multiple centers in China were retrospectively reviewed. Clinical features, laboratory data, and SLE Disease Activity Index 2000 (SLEDAI-2K) were collected. The primary outcomes were the 24h protein qualification, the ratio of urinary protein to creatinine, the rates of primary efficacy renal response (PR) and complete renal response (CR) according to the Belimumab International Study in Lupus Nephritis (BLISS-LN) 2. The percentage of SRI-4 responders and lupus low disease activity state (LLDAS) were used as additional indicators. Results: After treatment with telitacicept for 4, 12, 24 and 52 weeks, 31.37%, 50.98%, 68.63% and 68.42% of the LN patients, respectively, achieved a SRI-4 response. 3.9%, 3.9%, 21.6% and 36.8% patients achieved a LLDAS. The median of the SLEDAI-2K decreased from 10.0 (IQR:8.0-14.0) at baseline to 4.0 (IQR:2.0-8.0) at 24 weeks and 2.0 (IQR:2.0-6.0) at 52 weeks. The median of the PGA decreased from 1.5 (IQR:1.2-1.8) at baseline to 0.5 (IQR:0.4-1.0) at 24 weeks and 0.2 (IQR:0.2-0.8) at 52 weeks. Significant decreases in serum IgA, IgG and IgM levels were observed at 4 weeks and showed a downward trend at 12, 24, 52 weeks. For the primary outcome, the median of the 24h protein qualification of patients dropped from 1479.9 mg at baseline to 355 mg at 24 weeks and 328mg at 52 weeks. The median of the ratio of urinary to creatinine dropped from 1.36 at baseline to 0.44 at 24 weeks and 0.28 at 52 weeks. Notably, 54.9%, 62.7%,73.7% of the LN patients achieved PR and 41.2%, 52.9%, 68.4% of the patients achieved CR at 12, 24, 52 weeks, respectively. Conclusion: Telitacicept demonstrated good efficacy for LN patients in multiple centers clinical practice. Further investigations in a larger cohort are required to testify these findings. REFERENCES: 1 Wu D, Li J, Xu D, et al. Telitacicept in patients with active systemic lupus erythematosus: results of a phase 2b, randomised, double-blind, placebo-controlled trial. Ann Rheum Dis. 2023 Dec 21:ard-2023-224854. 2 FURIE R, ROVIN B H, HOUSSIAU F, et al. Two-Year, Randomized, Controlled Trial of Belimumab in Lupus Nephritis J. N Engl J Med, 2020, 383(12): 1117-28. Acknowledgements: NIL. Disclosure of Interests: None declared.