POS0228 BASELINE CHARACTERISTICS AND TREATMENT RESPONSE TO IXEKIZUMAB CATEGORISED BY SEX IN RADIOGRAPHIC AND NON-RADIOGRAPHIC AXIAL SPONDYLARTHRITIS PATIENTS THROUGH 52 WEEKS: DATA FROM 3 PHASE III, RANDOMIZED, CONTROLLED TRIALS
Authors: I. Van der Horst-Bruinsma, R. Bolce, T. Hunter, D. Sandoval, D. Zhu, V. J. Geneus, J. Lisse, S. Liu Leage, M. Magrey
Journal: Annals of the Rheumatic Diseases (2021)

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 (table 1). ASAS40 response rate with IXEQ4W was achieved in 39% of males with r-axSpA by week 16, and 44% by week 52. Females achieved 16.7% at week 16, and 33.3% at week 52. In nr-axSpA, 46% of IXEQ4W males achieved ASAS40 at week 16 and 30% at week 52. 23.9% of females achieved ASAS40 at week 16, increasing to 30.4% at week 52. Table 1. Baseline Characteristics of Patients Categorised by Sex Patients with r-axSpA (COAST-V/W ) (n=376 ) Patients with nr-axSpA (COAST-X ) (n=198 ) 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) &lt;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. Figure 1. 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