Improvement in spinal pain at night and its impact on long-term outcomes in radiographic axial spondyloarthritis

Introduction: Spinal pain at night is a major contributor to the patient burden of radiographic axial spondyloarthritis (r-axSpA), resulting in substantial functional limitations and impairment of health-related quality of life (QoL). Ixekizumab (IXE), an interleukin-17A inhibitor, has shown efficacy in patients with r-axSpA. Objective: To assess spinal pain at night improvement up to week (W) 52 in COAST-V and to determine if clinically important improvement in spinal pain at night at W16 is associated with improvement in disease activity and other patient-reported outcomes (PROs) at W16 and W52. Methods: The 52 W phase 3 COAST-V trial investigated the efficacy of IXE in patients with r-axSpA that were naïve to biological disease-modifying anti-rheumatic drug (bDMARD). Patients were randomised to IXE every two weeks (Q2W), IXE every four weeks (Q4W), adalimumab (ADA) Q2W, or placebo up to W16. Patients were categorised as achieving or not achieving a ≥3-point improvement, considered a clinically important improvement (CII), in spinal pain at night at W16. Associations between achieving CII in spinal pain at night at W16 and change from baseline in disease activity (ASDAS, ASAS40), Fatigue severity NRS, JSEQ, WPAI and the SF-36 survey, were tested using analysis of covariance (continuous variables) and logistic regression (binary variables). Results: At W16, 63.0 % (n=51), 46.7 % (n=42), and 32.2 % (n=28) of patients treated with IXE Q4W, ADA Q2W, and placebo, respectively, had reached a CII in spinal pain at night. Of those who were treated with IXE Q4W and achieved a CII in spinal pain at night at W16, 58.8 % and 66.7 % achieved an ASDAS <2.1 at W16 and W52 while 25.5 % and 29.4 % of patients also achieved ASDAS <1.3 at W16 and W52, respectively. Results at W16 and W52 show an improvement in disease activity, functioning, and health related QoL for patients who achieved a CII in spinal pain at night at W16. Conclusion: A larger proportion of patients treated with IXE Q4W achieved rapid and clinically meaningful improvement in spinal pain at night versus placebo, with improvements maintained up to W52. Achieving a CII in spinal pain at night at W16 was associated with improved disease activity, functioning, PROs, and QoL at W16 and W52. Trial registration: ClinicalTrials.gov