BIMEKIZUMAB ACHIEVED SUSTAINED IMPROVEMENTS IN EFFICACY OUTCOMES IN PATIENTS WITH AXIAL SPONDYLOARTHRITIS, REGARDLESS OF PRIOR TNF INHIBITOR TREATMENT: WEEK 52 POOLED RESULTS FROM TWO PHASE 3 STUDIES

M. Magrey, M. G. H. Van de Sande, M. Breban, F. Van den Bosch, C. Fleurinck, U. Massow, N. De Peyrecave, T. Vaux, X. Baraliakos, H. Marzo-OrtegaCase Western Reserve University, University Hospitals, Cleveland, United States of America Amsterdam UMC, University of Amsterdam, Department of Rheumatology & Clinical Immunology and Department of Experimental Immunology, Amsterdam Infection & Immunity Institute, Amsterdam, Netherlands Amsterdam Rheumatology & Immunology Center (ARC), Academic Medical Center, Amsterdam, Netherlands CHU Ambroise-Paré, Boulogne-Billancourt, Paris, France Ghent University and VIB Center for Inflammation Research, Department of Internal Medicine and Pediatrics, Ghent, Belgium UCB Pharma, N/A, Brussels, Belgium UCB Pharma, N/A, Monheim am Rhein, Germany UCB Pharma, N/A, Slough, United Kingdom Ruhr-University Bochum, Rheumazentrum Ruhrgebiet Herne, Bochum, Germany University of Leeds, NIHR Leeds Biomedical Research Centre, Leeds Teaching Hospitals NHS Trust and Leeds Institute of Rheumatic and Musculoskeletal Medicine, Leeds, United Kingdom  Background In patients (pts) with axial spondyloarthritis (axSpA), tumour necrosis factor inhibitors (TNFi) are the usual first line biologic treatment, yet many pts may experience loss of response over time, and some are intolerant to TNFis. Typically, response to second line biologics is limited in TNFi-inadequate responders (IR). Bimekizumab (BKZ) is a monoclonal IgG1 antibody that selectively inhibits IL-17F in addition to IL-17A. In the phase 3 BE MOBILE 1 and 2 studies, BKZ treatment resulted in rapid and sustained improvements in efficacy outcomes through 52 weeks (wks) in pts with active non‑radiographic (nr-)axSpA and r‑axSpA (i.e., ankylosing spondylitis [AS]). In studies of BKZ in psoriatic arthritis, similar efficacy between TNFi-naïve and TNFi-IR pts were observed. Objectives To assess the efficacy of BKZ in TNFi-naïve or -IR pts with active nr-axSpA and r‑axSpA through Wk 52 across multiple key endpoints. Methods In BE MOBILE 1 (nr-axSpA; NCT03928704) pts met Assessment of SpondyloArthritis international Society (ASAS) classification criteria and in BE MOBILE 2 (r-axSpA; NCT03928743) pts fulfilled modified New York and ASAS criteria. Pts were randomised to receive subcutaneous BKZ 160 mg every 4 wks (Q4W) or placebo (PBO) then BKZ 160 mg Q4W from Wk 16. This post hoc analysis reports pooled mean efficacy data, including disease activity, MRI inflammation, physical function, and quality of life (QoL), through Wk 52 of BE MOBILE 1 and 2, stratified by TNFi status (naïve/IR). TNFi-IR pts are defined as those who experienced intolerance, or IR, to prior treatment given at an approved dose for ≥12 wks. Results This pooled analysis included 505 TNFi-naïve and 81 TNFi-IR pts. 302/505 (59.8%) TNFi-naïve and 47/81 (58.0%) TNFi-IR pts were randomised to BKZ. At Wk 16, the proportion of pts achieving ASAS40 and AS Disease Activity Score (ASDAS)<2.1 (low disease activity) were higher in BKZ-randomised TNFi‑naïve/-IR pts vs PBO. In both TNFi-naïve/-IR continuous BKZ‑treated pts, responses were similar and increased to Wk 52 (Figure 1). Similar substantial reductions from baseline in ASDAS-CRP and MRI inflammation by Wk 16 were also achieved with BKZ vs PBO in both TNFi-naïve and IR pts; in continuous BKZ-treated pts this was sustained or further improved through 52 wks. Comparable improvements in physical function, nocturnal spinal pain and ASQoL were observed through 52 wks with BKZ in TNFi‑naïve/-IR pts (Table 1). Conclusion Across the full axSpA disease spectrum, BKZ treatment resulted in clinically relevant improvements in key efficacy outcomes vs PBO, including suppression of inflammation and improvements in physical function and QoL, regardless of prior TNFi exposure. The improvements with BKZ at Wk 16 were sustained to Wk 52. References [1] Noureldin B. Rheumatol (Oxf). 2018;57(suppl_6); [2] Boel A. Ann Rheum Dis. 2019;78:1545–9; [3] Baraliakos X. Arthritis Rheumatol. 2022;74 (suppl 9); [4] Mease P. Arthritis Rheumatol. 2022;74 (suppl 9). Image/graph: Table 1. Pooled efficacy endpoints across BE MOBILE 1 and 2 in TNFi-naïve and -IR pts Wk 16 Wk 52 TNFi-naïve TNFi-IR TNFi-naïve TNFi-IR PBO N=203 BKZ 160 mg Q4W N=302 PBO N=34 BKZ 160 mg Q4W N=47 BKZ 160 mg Q4W N=302 BKZ 160 mg Q4W N=47 ASDAS-CRP CfB [MI]mean (SE) –0.7 (0.1) –1.5 (0.1) –0.6 (0.1) –1.6 (0.1) –1.8 (0.1) –1.9 (0.2) BASDAI CfB [MI]mean (SE) –1.7 (0.1) –3.0 (0.1) –1.6 (0.4) –2.7 (0.3) –3.6 (0.1) –3.7 (0.3) SPARCC MRI SIJ CfB [OC]mean (SD) –0.9 (7.3) –5.3 (8.4) 1.4 (6.0) –5.6 (13.4) –5.9 (9.1) –6.9 (12.2) Berlin MRI Spine CfB [OC]mean (SD) –0.2 (1.5) –1.4 (3.2) 0.4 (1.3) –0.5 (1.9) –1.7 (3.6) –1.2 (2.1) BASFI CfB [MI]mean (SE) –1.1 (0.1) –2.3 (0.1) –0.5 (0.3) –2.2 (0.3) –2.8 (0.1) –2.9 (0.3) Nocturnal spinal pain CfB [MI]mean (SE) –1.7 (0.2) –3.4 (0.2) –2.1 (0.5) –3.3 (0.3) –4.1 (0.2) –3.9 (0.3) ASQoL CfB [MI]mean (SE) –2.8 (0.3) –5.1 (0.3) –2.4 (0.6) –4.2 (0.6) –5.8 (0.3) –4.7 (0.6) Wk 52 data shown only for continuous BKZ pts. n=95; n=144; n=13; n=15; n=130; n=94; n=140; n=12; n=127; n=15. Acknowledgements This study was funded by UCB Pharma. Medical writing support was provided by Costello Medical, funded by UCB Pharma. Disclosure of Interests Marina Magrey Consultant of: AbbVie, Eli Lilly, Novartis, Pfizer and UCB Pharma, Grant/research support from: AbbVie and UCB Pharma, Marleen G.H. van de Sande Speakers bureau: Janssen, Novartis and UCB Pharma, Consultant of: AbbVie, Novartis and UCB Pharma, Grant/research support from: Eli Lilly, Novartis and UCB Pharma, Maxime Breban Consultant of: Novartis and UCB Pharma, Grant/research support from: MSD, Filip van den Bosch Speakers bureau: AbbVie, BMS, Celgene, Janssen, Merck, Novartis, Pfizer and UCB Pharma, Consultant of: AbbVie, Amgen, Eli Lilly, Galapagos, Janssen, Merck, Novartis, Pfizer and UCB Pharma, Carmen Fleurinck Employee of: Employee of UCB Pharma, Ute Massow Employee of: Employee of UCB Pharma, Natasha de Peyrecave Employee of: Employee of UCB Pharma, Thomas Vaux Employee of: Employee of UCB Pharma, Xenofon Baraliakos Speakers bureau: AbbVie, BMS, Chugai, Eli Lilly, Galapagos, Gilead, MSD, Novartis, Pfizer and UCB Pharma, Paid instructor for: AbbVie, BMS, Chugai, Eli Lilly, Galapagos, Gilead, MSD, Novartis, Pfizer and UCB Pharma, Consultant of: AbbVie, BMS, Chugai, Eli Lilly, Galapagos, Gilead, MSD, Novartis, Pfizer and UCB Pharma, Helena Marzo-Ortega Speakers bureau: AbbVie, Biogen, Eli Lilly, Janssen, Moonlake, Novartis, Pfizer, Takeda and UCB Pharma, Consultant of: AbbVie, Biogen, Eli Lilly, Janssen, Moonlake, Novartis, Pfizer, Takeda and UCB Pharma, Grant/research support from: Janssen, Novartis and UCB. Keywords: bDMARD, Spondyloarthritis, Clinical trials DOI: 10.1136/annrheumdis-2023-eular.836Citation: , volume 82, supplement 1, year 2023, page 876Session: Spondyloarthritis - treatment (Poster View)