Background: Axial spondyloarthritis (axSpA) is a chronic inflammatory disease of the axial skeleton comprising two subtypes within the same spectrum: radiographic (r-axSpA) and non-radiographic (nr-axSpA). Previous studies have shown that clinical presentation and treatment response of males and females may differ 1 despite similar disease burden. 2 Ixekizumab (IXE), a high-affinity monoclonal antibody that selectively targets interleukin-17A, has demonstrated superior efficacy to placebo in the treatment of patients with r-axSpA (COAST-V/W [bDMARD- naïve/TNFi-experienced]) and nr-axSpA (COAST-X [bDMARD-naïve]). 3
Objectives: Assess baseline characteristics and treatment response to IXE categorised by sex in patients with r-axSpA and nr-axSpA for up to 52 weeks.
Methods: Patients fulfilled the ASAS classification criteria for r-axSpA or nr-axSpA. Patients were randomized to receive 80 mg subcutaneous IXE every 2 weeks (Q2W) or 4 weeks (Q4W), or to placebo (PBO) [16 weeks COAST-V/W; 52 weeks COAST-X]. Baseline characteristics and treatment outcomes were assessed. Patients were categorised by sex, missing data was controlled for using non-responder imputation (NRI) and modified baseline observation carried forward (mBOCF) analysis was conducted on continuous efficacy variables.
Results: At baseline, females were older, with significantly higher pain and fatigue scores and peripheral joint symptoms (
Baseline Characteristics of Patients Categorised by Sex
Patients with r-axSpA
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Patients with nr-axSpA
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Characteristic | Male (n=298 ) | Female (n=78 ) | p value | Male (n=99 ) | Female (n=99 ) | p value |
Age at onset (yrs ), mean (SD) | 26.5 (8.7) | 30.1 (10.1) | 0.002* | 27.9 (7.7) | 32.0 (10.7) | 0.002* |
Symptom duration (yrs ), mean (SD) | 16.7 (10.5) | 17.8 (12.2) | 0.420 | 9.5 (9.2) | 12.3 (11.3) | 0.057 |
ASDAS , mean (SD) | 4.0 (0.8) | 3.9 (0.7) | 0.304 | 3.7 (0.8) | 3.9 (0.8) | 0.143 |
BASDAI , mean (SD) | 7.10 (1.4) | 7.4 (1.5) | 0.179 | 6.9 (1.4) | 7.4 1.4) | 0.013* |
Fatigue/tiredness (BASDAI Q1 ), mean (SD) | 7.4 (1.6) | 7.8 (1.5) | 0.036* | 7.0 (1.6) | 7.9 (1.5) | <0.001* |
Spinal pain (BASDAI Q2 ), mean (SD) | 7.9 (1.5) | 8.0 (1.5) | 0.682 | 7.5 (1.4) | 7.9 (1.5) | 0.029* |
Pain/swelling in other joints (BASDAI Q3 ), mean (SD) | 6.5 (2.1) | 6.9 (2.2) | 0.129 | 6.6 (2.3) | 7.2 (1.9) | 0.039* |
Tenderness to touch/pressure (BASDAI Q4 ), mean (SD) | 6.8 (1.8) | 7.0 (1.9) | 0.339 | 6.6 (1.9) | 6.8 (1.8) | 0.404 |
Morning stiffness (BASDAI Q5 ), mean (SD) | 7.5 (1.6) | 7.7 (1.8) | 0.504 | 7.3 (1.7) | 7.7 (1.9) | 0.137 |
Morning stiffness duration (BASDAI Q6 ), mean (SD) | 6.5 (2.3) | 6.5 (2.8) | 0.944 | 6.3 (2.3) | 6.6 (2.5) | 0.392 |
Spinal pain at night NRS , mean (SD) | 7.4 (1.5) | 7.8 (1.7) | 0.033* | 7.0 (1.8) | 7.6 (1.8) | 0.027* |
BASFI , mean (SD) | 6.8 (1.8) | 7.0 (2.0) | 0.466 | 6.2 (1.8) | 6.7 (2.1) | 0.108 |
SF-36 PCS , mean (SD) | 30.9 (8.3) | 28.9 (8.2) | 0.075 | 33.1 (7.7) | 32.1 (7.2) | 0.348 |
p-value from Fisher’s exact test analysis of variance (ANOVA) with sex as a factor for continuous data. Data includes pooled IXEQ2W and IXEQ4W.
Conclusion: This analysis demonstrates that for the axSpA disease spectrum, females present with higher disease burden as reflected by higher scores in fatigue/tiredness, and spinal pain at night. Our findings indicate that males and females respond to IXE; however, females experience this benefit later in their treatment course, with a more prolonged attainment of peak response.
REFERENCES:
[1]van der Horst-Bruinsma IE, et al. Ann Rheum Dis. 2019;78:1550-1558.
[2]Zhao SS, et al. Rheumatology. 2019;58:2025-2030.
[3]Deodhar A, et al. Lancet. 2020;395:53-64.
COAST-V/W ASAS40 (ITT, NRI ) Patients initially randomized to PBO in COAST-V/W switched to IXEQ2W or Q4W at week 16 by study design; PBO data are summarised up to week 16.
Acknowledgements: Writing support was provided by Dr Geraldine Fahy, an employee of Eli Lilly and Company
Disclosure of Interests: Irene van der Horst-Bruinsma Speakers bureau: BMS, AbbVie, Pfizer, UCB, MSD, Consultant of: Abbvie, UCB, MSD, Lilly, Novartis, Grant/research support from: MSD, Pfizer, AbbVie, Rebecca Bolce Shareholder of: Eli Lilly, Employee of: Eli Lilly, Theresa Hunter Shareholder of: Eli Lilly, Employee of: Eli Lilly, David Sandoval Shareholder of: Eli Lilly, Employee of: Eli Lilly, Danting Zhu Employee of: Eli Lilly, Vladimir J. Geneus Employee of: Eli Lilly, Jeffrey Lisse Shareholder of: Eli Lilly, Employee of: Eli Lilly, Soyi Liu Leage Shareholder of: Eli Lilly, Employee of: Eli Lilly, Marina Magrey Consultant of: Novartis, Eli Lilly, Pfizer, Abbvie, UCB and Jansen, Grant/research support from: Amgen, AbbVie, and UCB Pharma