OP0017 RECAPTURE RATES WITH IXEKIZUMAB AFTER WITHDRAWAL OF THERAPY IN PATIENTS WITH AXIAL SPONDYLOARTHRITIS: RESULTS AT WEEK 104 FROM A RANDOMIZED PLACEBO-CONTROLLED WITHDRAWAL STUDY

Background COAST-Y is the first study to evaluate effect of continuing vs withdrawing an IL-17A antagonist, Ixekizumab (IXE) on maintenance disease control in patients (pts) with ankylosing spondylitis and non-radiographic axial spondyloarthritis through 104 Weeks (wks). Objectives Here, we describe final results pts re-randomized either placebo (PBO; IXE Withdrawal) or IXE, who experienced flare, recaptured response before after open label retreatment during COAST-Y. Methods ( NCT03129100 ) a Phase 3, long-term extension that included double-blind, PBO-controlled, randomized withdrawal-retreatment period (RWP). Eligible completed originating (COAST-V, -W, -X) entered 24-Week (Wk) lead-in received 80 mg every 2 (Q2W) 4 wks (Q4W) (the treatment regimen at end study); receiving PBO COAST-X were assigned Q4W Pts achieved remission (Ankylosing Spondylitis Disease Activity Score (ASDAS) <1.3 (inactive disease; ID) least once Wk 16 20, <2.1 (low activity; LDA) both visits) 2:1 24 continue (as per period) withdrawn PBO. subsequently flare (ASDAS ≥2.1 consecutive visits ASDAS >3.5 any visit) switched Q2W next visit (same as period). Time was analyzed using Kaplan-Meier method comparison performed log-rank test. The observed proportion LDA ID summarized for retreated IXE. Results A total 155 met criteria RWP (PBO [IXE withdrawal], N=53; Q4W, N=48; Q2W, N=54) 138 104. At 104, significantly more combined group (75.5%, p<0.001, Q4W: 75.0%, p<0.001; Q2W: 75.9%, p<0.001) remained free (Figure 1). Notably, 35.8% (IXE never flare. Of 24-104 (N=28), switching retreatment, while 23 19 (Table continuously treated (N=13), 7 5 after. Figure 1. (%) weeks. ‡p<0.001, †p<0.01, *p<0.05 Withdrawal). Table Recapture weeks among (ixekizumab withdrawal)-treated Total flared open-label ixekizumab Placebo withdrawal (N=28 activity status Recaptured 1 (≤16 weeks) 14 (>16 0 week 27/28 (96%) 20/28 (71%) Data are presented n, row n only all other rows. In each column, denominator 28. ASDAS, Ankylosing Score; ID, inactive LDA, low including ID; N, number analysis population. Conclusion less likely experience withdrawal). vast majority from over half retreatment. This may provide support require interruption therapy. Acknowledgements sponsored by Eli Lilly Company. Medical writing services provided Edel Hughes, PhD Sumeet Sood, Company, funded Disclosure Interests Robert B.M. Landewé Consultant of: Rheumatology Consultancy BV, AbbVie, UCB, Pfizer, Novartis, Celgene, Denis Poddubnyy Speakers bureau: Bristol Myers Squibb, Janssen, Merck Sharp & Dohme, Roche, UCB Pharma, Grant/research from: Proton Rahman Amgen, Bristol-Myers Merck, Rebecca Bolce Shareholder Employee Soyi Liu Leage Jeffrey Lisse Ann Leung: None declared, So Young Park Lianne S. Gensler UCB.