SAT0403 EFFICACY AND SAFETY OF 108 WEEKS’ BIMEKIZUMAB TREATMENT IN PATIENTS WITH PSORIATIC ARTHRITIS: INTERIM RESULTS FROM A PHASE 2 OPEN-LABEL EXTENSION STUDY
Authors: I. Mcinnes, J. F. Merola, P. J. Mease, L. C. Coates, P. Joshi, J. Coarse, B. Ink, C. T. Ritchlin
Journal: Annals of the Rheumatic Diseases (2020)

Background: Bimekizumab (BKZ), a monoclonal antibody that selectively neutralises IL-17A and IL-17F, has shown clinical improvements in skin and joint outcomes over 48 weeks (wks) in patients (pts) with active psoriatic arthritis (PsA). 1 Objectives: To report 2-year interim results from a phase 2b dose-ranging study (BE ACTIVE; NCT02969525 ) and open-label extension (OLE; NCT03347110 ) of BKZ in pts with PsA. Methods: Design of the dose-ranging study is described elsewhere. 1 Pts who completed 48 wks’ BKZ treatment without meeting withdrawal criteria were eligible for OLE entry. All OLE pts received BKZ 160 mg Q4W, irrespective of prior dosing regimen. Data are presented from dose-ranging study baseline (BL) to OLE Wk 60 (Wk 108 total). Efficacy outcomes are reported for the full analysis set (FAS): pts who received ≥1 dose BKZ (specifically those randomised to 160 mg, 160 mg with 320 mg loading dose [LD], or 320 mg at BL), with BL efficacy measurements to allow subsequent determination of ACR50. Outcomes include ACR20/50/70, body surface area (BSA) 0%, minimal disease activity (MDA), and enthesitis/dactylitis resolution. Rates of treatment-emergent adverse events (TEAEs) are reported for the Safety Set (SS; pts who received ≥1 dose BKZ in the dose-ranging study). Results: BL mean (SD) tender/swollen joint counts were 21.7 (15.7) and 11.2 (8.4). 80 (65.0%) pts had BSA ≥3% and dactylitis/enthesitis were present in 41 (33.3%) and 68 (55.3%) pts. Over 108 wks’ BKZ treatment, improvements were observed in skin/joint outcomes: ACR50 (66.7%), BSA 0% (75.4%), MDA (65.6%), and resolution of dactylitis (65.9%) and enthesitis (77.9%) (Table). Serious TEAEs occurred in 9.3% pts (Table); no deaths or major adverse cardiac events were reported. Oral candidiasis occurred in 16 (7.8%) pts (no serious cases). Conclusion: BKZ leads to long-term efficacy for skin/joint manifestations of PsA, with &gt;50% pts achieving high thresholds of disease control (ACR50, BSA 0%, MDA) after 108 wks’ treatment. The safety profile reflects previous observations. 1 References: [1]Ritchlin CT. Ann Rheum Dis 2019;78:127–8. Table. Outcomes at OLE Wk 60 (Wk 108 total) BKZ 160 mg [a] (N=82 ) BKZ 320 mg [a] (N=41 ) BKZ total (N=123 ) OC NRI OC NRI OC NRI Efficacy (FAS) n (%) ACR20 53/62 ( 85.5 ) 53 ( 64.6 ) 29/37 ( 78.4 ) 29 ( 70.7 ) 82/99 ( 82.8 ) 82 ( 66.7 ) ACR50 41/62 ( 66.1 ) 41 ( 50.0 ) 25/37 ( 67.6 ) 25 ( 61.0 ) 66/99 ( 66.7 ) 66 ( 53.7 ) ACR70 34/62 ( 54.8 ) 34 ( 41.5 ) 19/37 ( 51.4 ) 19 ( 46.3 ) 53/99 ( 53.5 ) 53 ( 43.1 ) BSA 0% [b] 35/42 ( 83.3 ) – 14/23 ( 60.9 ) – 49/65 ( 75.4 ) – MDA [c] 43/61 ( 70.5 ) 43 ( 52.4 ) 20/35 ( 57.1 ) 20 ( 48.8 ) 63/96 ( 65.6 ) 63 ( 51.2 ) Dactylitis resolution – 16/27 ( 59.3 ) – 11/14 ( 78.6 ) – 27/41 ( 65.9 ) Enthesitis resolution [c] – 34/45 ( 75.6 ) – 19/23 ( 82.6 ) – 53/68 ( 77.9 ) Safety (SS ) n (%) [EAER] BKZ 160 mg [d] (N=198 ) BKZ 320 mg [d] (N=80 ) BKZ total [d, e] (N=204 ) Any TEAE 163 (82.3) [160.9] 57 (71.3) [299.8] 179 (87.7) [181.1] Study discontinuation due to TEAEs 17 (8.6) 1 (1.3) 18 (8.8) Permanent withdrawal of study drug due to TEAEs 16 (8.1) 2 (2.5) 18 (8.8) Drug-related TEAEs 72 (36.4) 29 (36.3) 92 (45.1) Serious TEAEs 19 (9.6) [4.8] 0 19 (9.3) [4.1] [a] BKZ 160 mg pts received this dose continuously to Wk 108 (includes those originally assigned to 160 mg with LD); BKZ 320 mg pts were dose-reduced to 160 mg at OLE entry; [b] Pts with BSA ≥3% at BL; [c] Data from OLE Wk 72 (Wk 120 total); [d] Dose received at TEAE onset (pts may be counted in multiple columns); [e] Includes pt time on BKZ 16 mg. EAER: exposure-adjusted event rate; NRI: non-responder imputation; OC: observed case. Acknowledgments: This study was funded by UCB Pharma. Editorial services were provided by Costello Medical. Disclosure of Interests: Iain McInnes Grant/research support from: Bristol-Myers Squibb, Celgene, Eli Lilly and Company, Janssen, and UCB, Consultant of: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly and Company, Gilead, Janssen, Novartis, Pfizer, and UCB, Joseph F. Merola Consultant of: Merck, AbbVie, Dermavant, Eli Lilly, Novartis, Janssen, UCB Pharma, Celgene, Sanofi, Regeneron, Arena, Sun Pharma, Biogen, Pfizer, EMD Sorono, Avotres and LEO Pharma, Philip J Mease Grant/research support from: AbbVie, Amgen, Bristol-Myers Squibb, Janssen, Eli Lilly, Novartis, Pfizer, Sun Pharma, UCB Pharma, Consultant of: AbbVie, Amgen, Bristol-Myers Squibb, Celgene, Janssen, Eli Lilly, Galapagos, Gilead, Novartis, Pfizer, Sun Pharma, UCB Pharma, Speakers bureau: AbbVie, Amgen, Bristol-Myers Squibb, Celgene, Genentech, Janssen, Novartis, Pfizer, UCB Pharma, Laura C Coates: None declared, Paulatsya Joshi Employee of: UCB Pharma, Jason Coarse Employee of: UCB Pharma, Barbara Ink Shareholder of: GlaxoSmithKline and UCB Pharma, Employee of: UCB Pharma, Christopher T. Ritchlin Grant/research support from: UCB Pharma, AbbVie, Amgen, Consultant of: UCB Pharma, Amgen, AbbVie, Lilly, Pfizer, Novartis, Gilead, Janssen