POS0924 PREDICTORS OF 1-YEAR TREATMENT RESPONSE AMONG UPADACITINIB-TREATED PATIENTS WITH ANKYLOSING SPONDYLITIS: A POST HOC ANALYSIS OF SELECT-AXIS 1
Authors: M. Magrey, S. Ramiro, M. Pinheiro, T. Gao, F. Ganz, I. H. Song, A. Biljan, N. Haroon, M. Rudwaleit
Journal: Annals of the Rheumatic Diseases (2021)

Background: Upadacitinib (UPA) is an oral Janus kinase inhibitor that has demonstrated efficacy and safety among patients with ankylosing spondylitis (AS) in the phase 2/3 SELECT-AXIS 1 study. 1 If identified, early predictors of treatment response may inform treat-to-target strategies and optimize patient outcomes in AS. Objectives: To determine whether baseline (BL) characteristics or early responses predict clinical response at 1 year in UPA-treated patients with AS. Methods: In the double-blind, randomized, placebo (PBO)-controlled SELECT-AXIS 1 study, patients received UPA 15 mg once daily or PBO until Week 14. 1 At Week 14, PBO-treated patients switched to UPA 15 mg; patients originally randomized to UPA continued UPA therapy. Data from patients in the PBO and UPA arms were combined based on overall exposure to UPA; in the switch arm, exposure was defined as current visit minus 14 weeks (time of switch). The following outcomes were assessed at 1 year: Ankylosing Spondylitis Disease Activity Score with C-reactive protein (ASDAS[CRP]) inactive disease (ID; &lt;1.3) and low disease activity (LDA; &lt;2.1), Assessment of SpondyloArthritis International Society (ASAS) partial remission (PR), and ≥40% improvement in ASAS criteria (ASAS40) response. The ability of BL characteristics, efficacy at Week 12, and back pain at Week 12 to predict 1-year outcomes was assessed using a univariable logistic regression model generating odds ratios (ORs; 95% confidence intervals). LASSO regression was used to select the best-fitted multivariable model at Week 12 for each outcome measure. Results: Among 187 patients who received or switched to UPA 15 mg, 70 (37.4%), 134 (71.7%), 73 (39.0%), and 131 (70.1%) achieved ASDAS(CRP) ID, ASDAS(CRP) LDA, ASAS PR, and ASAS40, respectively, following 1 year of UPA treatment. No meaningful predictors of 1-year efficacy outcomes were identified based on BL demographics (including disease duration, gender, and human leukocyte antigen B27 status) or BL disease characteristics (including ASDAS, Bath Ankylosing Spondylitis Disease Activity Index, and CRP levels). In univariable analyses, Week 12 responses based on several disease activity measures and patient-reported outcomes (PROs), including reductions (much better improvement [MBI], ≥30/≥50/≥70% reduction, or improvement) in back pain score, along with lower scores for back pain at Week 12, were associated with the achievement of ASDAS(CRP) ID, ASDAS(CRP) LDA, ASAS PR, and ASAS40 at 1 year (Figure 1). In a multivariable analysis, improvement from BL to Week 12 in back pain score consistently predicted several efficacy outcomes at 1 year. Conclusion: In upadacitinib-treated patients with AS, improvement in PROs and reduction in back pain score at 12 weeks predicted clinical outcomes at 1 year. References: [1]van der Heijde D, et al. Lancet 2019;394:2108–17. Figure 1. Association between Week 12 response or back pain at Week 12 and achievement of efficacy outcomes at 1 year (univariable analysis) All ASDAS scores are calculated using C-reactive protein ASDAS CII: change from BL ≥1.1; ASDAS MI: change from BL ≥2.0; MBI back pain: ≥2-point reduction in absolute score and ≥33% reduction from BL on a 0–10 NRS ASAS, Assessment of SpondyloArthritis International Society; ASAS40, ≥40% improvement in ASAS criteria; ASDAS, Ankylosing Spondylitis Disease Activity Score; BASDAI50, ≥50% improvement in the Bath Ankylosing Spondylitis Disease Activity Index; BL, baseline; CI, confidence interval; CII, clinically important improvement; ID, inactive disease; LDA, low disease activity; MBI, much better improvement; MI, major improvement; NRS, numeric rating scale; OR, odds ratio; PR, partial remission Acknowledgements: AbbVie funded this study; contributed to its design; participated in data collection, analysis, and interpretation of the data; and participated in the writing, review, and approval of the abstract. No honoraria or payments were made for authorship. Medical writing support was provided by Laura Chalmers, PhD, of 2 the Nth (Cheshire, UK), and was funded by AbbVie. Disclosure of Interests: Marina Magrey Consultant of: Consultant for Janssen and Novartis; member of advisory boards for Eli Lilly, Janssen, Novartis, and UCB, Grant/research support from: AbbVie, Sofia Ramiro Consultant of: AbbVie, Eli Lilly, MSD, Novartis, Sanofi, and UCB, Grant/research support from: MSD, Marcelo Pinheiro Consultant of: AbbVie, Eli Lilly, Janssen, and Novartis, Tianming Gao Employee of: AbbVie employee and may own stock or options, Fabiana Ganz Employee of: AbbVie employee and may own stock or options, In-Ho Song Employee of: AbbVie employee and may own stock or options, Ana Biljan Employee of: AbbVie employee and may own stock or options, Nigil Haroon Consultant of: AbbVie, Amgen, Eli Lilly, Janssen, MSD, Novartis, Pfizer, and UCB, Martin Rudwaleit Consultant of: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly, Janssen, MSD, Novartis, Pfizer, Roche, and UCB