POS0912 LONG-TERM TREATMENT WITH IXEKIZUMAB IN PATIENTS WITH AXIAL SPONDYLOARTHRITIS: TWO-YEAR RESULTS FROM COAST-Y

Abstract

Background: The efficacy and safety of the interleukin‐17 inhibitor ixekizumab (IXE) for the treatment of radiographic (r‐) and non‐radiographic (nr‐) axial spondyloarthritis (axSpA) has been shown for up to 52 weeks.1‐2 Objectives: To study the efficacy and safety of ixekizumab in the treatment of patients with r‐and nr‐axSpA for up to 116 weeks. Methods: COAST‐Y (NCT03129100) is the 2‐year extension of the COAST‐V, ‐W, and ‐X trials. Patients continued with the dose received at the end of the originating trial at Week 52, either with 80 mg IXE every 4 weeks (Q4W) or every 2 weeks (Q2W). Patients who had been assigned to adalimumab or placebo were re‐randomized to IXE Q4W or Q2W at Week 16 in COAST‐V and ‐W. Patients who had received placebo for 52 weeks in COAST‐X were switched to IXE Q4W in COAST‐Y. Patients who switched from placebo or adalimumab treatment to IXE (COAST‐V, ‐W, or ‐X) or from IXE Q4W to open‐label IXE Q2W (COAST‐X) during the originating studies were analyzed separately from patients continuously treated with IXE. Standardized efficacy measures were used (Table 1). Missing data were handled by non‐responder imputation for categorical data and modified baseline observation carried forward for continuous data. Safety data were analyzed for all patients who received ≥1 dose of IXE. Results: Of the 773 patients enrolled in COAST‐Y, 86.0% completed Week 116 of treatment (52 weeks of one of the originating trials and 64 weeks of COAST‐Y). Among the patients continuously treated with IXE for 116 weeks (IXE Q4W: N=157; IXE Q2W: N=195), 46.9% achieved low disease activity (ASDAS <2.1), and 19.9% achieved ASAS partial remission at 116 weeks (Table 1; Figure 1). In comparison to baseline, 56.0% achieved ASAS40 (Table 1). The mean change from baseline at Week 116 was ‐1.70 for ASDAS, ‐2.98 for BASFI, and 9.22 for SF‐36 Physical Component Summary (Table 1). Similar observed responses were achieved between the patients continuously treated with IXE and patients initially treated with placebo or adalimumab. For the 932 patients in the safety population, no new safety signals were identified. Conclusion: Ixekizumab treatment led to consistent and sustained long‐term improvements in disease activity and quality of life in patients with r‐and nr‐ax‐SpA, with no new safety signals after up to 2 years of treatment.