Objectives: Assess baseline characteristics and treatment response to ixekizumab (IXE) categorised by sex in patients with radiographic axial spondyloarthritis (r-axSpA) and non-radiographic axSpA (nr-axSpA) up to 52 weeks.
Methods: Data were analysed from three randomised controlled trials of IXE through 52 weeks. Patients fulfilled ASAS classification criteria for r-axSpA or nr-axSpA and were randomised to receive 80 mg subcutaneous administration of IXE every 2 weeks (Q2W) or 4 weeks (Q4W), or placebo (16 weeks COAST-V/W; 52 weeks COAST-X). Baseline characteristics and treatment outcomes were assessed. Patients were categorised by sex; methods included non-responder imputation for categorical variables, and modified baseline observation carried forward for continuous efficacy variables.
Results: At presentation, female patients had higher disease burden as reflected by significantly higher spinal pain at night, fatigue scores and pain/swelling in joints other than the neck, back or hip. ASAS40 response rate with the approved label dose, IXEQ4W, was achieved in 39% of male patients with r-axSpA by week 16, and 44% by week 52. For female patients, 16.7% and 33.3% achieved ASAS40 at week 16 and 52, respectively. In nr-axSpA, 46% of male patients achieved ASAS40 at week 16 and 30% at week 52. In total, 23.9% of female patients achieved ASAS40 at week 16, and 30.4% at week 52.
Conclusions: This analysis demonstrates that for the axSpA disease spectrum, female patients present with higher disease burden. Following treatment with IXE, there is a higher proportion of male responders up to 16 weeks, while female patients show less robust responses for the first 16 weeks but larger responses from weeks 16 through 52.
Keywords: Axial spondyloarthritis; Ixekizumab; Non-radiographic; Radiographic; Sex differences.
© 2022. The Author(s).