LAUSR

OBJECTIVE To evaluate response rates at week 16 with ixekizumab in patients with radiographic axial spondyloarthritis (r-axSpA) and elevated or normal/low baseline inflammation, measured by serum C-reactive protein (CRP) or spinal MRI, using data from 2 randomized, double-blind, placebo-controlled phase III trials. METHODS Biologic-naive (COAST-V) or tumor necrosis factor inhibitor-experienced (COAST-W) adults with active r-axSpA received 80 mg ixekizumab every 2 weeks (IXEQ2W) or 4 weeks (IXEQ4W) or placebo (PBO); or active reference (40 mg adalimumab Q2W; ADA) in COAST-V. At week 16, patients receiving ixekizumab continued as assigned; patients receiving PBO or ADA were re-randomized 1:1 to IXEQ2W or IXEQ4W through week 52. ASAS40 response rates were examined by baseline CRP (≤5 or > 5 mg/l) and SPARCC MRI spine inflammation score (<2 or ≥ 2). RESULTS In the COAST-V/W integrated dataset (N = 567), significantly more patients treated with ixekizumab achieved ASAS40 response at week 16 by CRP ≤5 mg/l (27% IXEQ4W p<0.05, 35% IXEQ2W p<0.01 vs 12% PBO), CRP >5 mg/l (39% IXEQ4W p<0.001, 43% IXEQ2W p<0.001 vs 17% PBO), SPARCC MRI spine score <2 (40% IXEQ4W p<0.01, 52% IXEQ2W p<0.001 vs 16% PBO), and SPARCC MRI spine score ≥2 (44% IXEQ4W p<0.001, 47% IXEQ2W p<0.001 vs 19% PBO). ASAS40 response was observed with CRP ≤5 mg/l and SPARCC MRI spine score <2 with IXEQ4W (29%) and was significant with IXEQ2W (48%, p<0.05) vs PBO (13%). CONCLUSION Ixekizumab demonstrated efficacy in the treatment of ankylosing spondylitis/r-axSpA in patients with and without elevated CRP or evidence of spinal inflammation on MRI. TRIAL REGISTRATION ClinicalTrials.gov, https://clinicaltrials.gov: NCT02696785, NCT02696798.