Xeligekimab, an Interleukin-17A Antagonist for Active Radiographic Axial Spondyloarthritis in Chinese Patients: 16- and 48-Week Results from a Phase III, Randomized, Double-Blind, Placebo-Controlled Study.

BACKGROUND: Xeligekimab is a novel immunoglobulin G4 (IgG4) monoclonal antibody targeting interleukin-17A (IL-17A). In a phase III trial in patients with plaque psoriasis, xeligekimab showed efficacy and safety consistent with other IL-17A inhibitors, supporting its potential application in the treatment of spondyloarthritis. OBJECTIVE: This phase III trial aimed to investigate the efficacy and safety of xeligekimab in patients with radiographic axial spondyloarthritis (r-axSpA). METHODS: This was a phase III study conducted at multiple centers in China. Eligible patients were randomly assigned (1:1:1) to receive xeligekimab 100 mg, xeligekimab 200 mg, or placebo. Randomization was stratified by medication history (biologic-experienced vs. biologic-naïve) and weight (≥ 70 kg vs. < 70 kg). The primary endpoint was the proportion of patients achieving an Assessment of SpondyloArthritis International Society 20 (ASAS20) response at week 16. A key secondary endpoint was the ASAS40 response rate at the same time point. RESULTS: A total of 465 patients were recruited. A significantly higher proportion of patients receiving xeligekimab 200 mg (n = 114 (74.0%); p < 0.001, 95% confidence interval (CI) 28.5-48.4) and xeligekimab 100 mg (n = 102 (65.8%); p < 0.001, 95% CI 19.4-41.0) achieved an ASAS20 response compared to the placebo group (n = 56 (35.9%)) at week 16. Similarly, a significantly higher ASAS40 response rate was observed in the xeligekimab 100 mg group (n = 62 (40.0%); p < 0.001) and the xeligekimab 200 mg group (n = 64 (41.6%); p < 0.001) compared to placebo. Adverse events were similar across all groups, with serious adverse events occurring in 1.6% of the treatment group during the core treatment period. No unexpected safety signals were reported through week 48. CONCLUSION: Xeligekimab demonstrated significant efficacy in improving the signs and symptoms of active r-axSpA in Chinese patients at week 16, with sustained effects observed through week 48 and no new safety signals identified. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT05881785 (Date: 21 May 2023).