Bimekizumab improves key symptoms, disease activity and function in patients across the full spectrum of axial spondyloarthritis up to week 24: results from two phase 3 studies

Abstract Background/Aims Bimekizumab (BKZ) is a monoclonal IgG1 antibody that selectively inhibits IL-17F in addition to IL-17A. BKZ demonstrated rapid and clinically meaningful improvements in disease activity across the full spectrum of axial spondyloarthritis (axSpA; active non-radiographic axSpA [nr-axSpA; BE MOBILE 1, NCT03928704] and ankylosing spondylitis [AS] / radiographic axSpA [r-axSpA; BE MOBILE 2, NCT03928743]). Here we present clinical outcomes from the ongoing phase 3 studies up to week (wk) 24. Methods BE MOBILE 1 and 2 have similar study designs: 16-wk double-blind period followed by a 36-wk maintenance period. Patients were randomised (1:1 in BE MOBILE 1 and 2:1 in BE MOBILE 2) to BKZ 160 mg every 4 wks (Q4W) or placebo (PBO). All patients received BKZ 160 mg Q4W from wk16. ASAS40 and BASDAI50 rates, mean change from baseline (CfB) in BASDAI (total and components) and BASFI scores are reported up to wk24. Missing data is imputed using non-responder or multiple imputation. Results Overall, 240/254 (94.5%; nr-axSpA) and 313/332 (94.3%; r-axSpA) patients completed the studies up to wk24. Both studies met their primary (ASAS40) and ranked secondary endpoints at wk16. Higher BASDAI50 response rates and larger mean reduction in BASDAI and BASFI scores were seen at wk16 for BKZ versus PBO (Table). After switching to BKZ, mean changes in BASDAI and BASFI scores for patients in the PBO group reached levels similar to BKZ-treated patients. 50.8% of nr-axSpA and 55.5% of r-axSpA patients had ≥1 treatment emergent adverse events (TEAE) and incidence of serious TEAEs was low up to wk24 (0.4% and 3.6%). No systemic candidiasis, MACE or deaths were reported with BKZ in either study up to wk24. No IBD was reported in BE MOBILE 1 (nr-axSpA), there was low incidence of adjudicated IBD in BE MOBILE 2 (r-axSpA: 0.3%). Incidence of uveitis was low in both studies (nr-axSpA: 4.8% [PBO], 1.6% [BKZ]; r-axSpA: 4.5% [PBO], 0% [BKZ]) at wk16. Conclusion Dual inhibition of IL-17A and IL-17F with BKZ provided significant improvement in key signs and symptoms, disease activity and physical function across the full spectrum of axSpA. No new safety signals were observed. Disclosure K. Gaffney: Consultancies; KG has received honoraria or consultancy fees from Novartis, AbbVie, UCB Pharma, Eli Lilly and Pfizer. Shareholder/stock ownership; KG is a shareholder of Rheumatology Events. Member of speakers’ bureau; KG has paticipated in speaker's bureau for Novartis, UCB Pharma, AbbVie and Eli Lilly. Grants/research support; KG has received grants/research support from NASS, Versus Arthritis, AbbVie, Pfizer, UCB Pharma, Norvartis, Eli Lilly, Cellgene, Celltrion, Janssen, Gilead and Biogen. Other; KG has received meeting expenses from AbbVie, Eli Lilly, Roche, Novartis, Pfizer and UCB Pharma. N. McKay: Member of speakers’ bureau; NM has received Speaker' bureau from Gilead. Other; NM has received travel fees from UCB Pharma and Gilead. R. Sengupta: Consultancies; RS has honoraria or consultancy fees from Abbvie, Biogen, Novartis, Celgene, Lilly, Chugai, MSD and UCB Pharma. Grants/research support; RS has received grants/ research support from AbbVie, Celgene, Novartis and UCB Pharma. Other; RS is on the advisory boards for AbbVie, Biogen, Chugai, Lilly, Novartis and UCB Pharma. C. Fleurinck: Other; CF is an employee of UCB Pharma. C. de la Loge: Consultancies; CdlL is a consultant to UCB Pharma, Brussels, Belgium. U. Massow: Other; UM is an employee of UCB Pharma. V. Taieb: Other; VT is employee of UCB Pharma. S. Zhao: Honoraria; SZ has received honoraria from UCB Pharma. H. Marzo-Ortega: Grants/research support; HMO has received grants/research support from Janssen, Novartis and UCB Pharma. Other; HMO has received honoraria and/or consultancy and/or speaker fees from Abbvie, Biogen, Celgene, Janssen, Eli-Lilly, Moonlake, Novartis, Pfizer and UCB Pharma.