P171 Bimekizumab in bDMARD-naïve patients with active psoriatic arthritis: improvements in PsARC over 24 weeks in the Phase 3 BE OPTIMAL trial

Abstract

Abstract Background/Aims Bimekizumab (BKZ) is a humanised monoclonal IgG1 antibody that acts by selectively inhibiting IL-17F in addition to IL-17A and has demonstrated clinical efficacy vs placebo (PBO) in both joint and skin outcomes in patients with active psoriatic arthritis (PsA). We report interim 24-week (wk) PsARC response rates along with HRQoL estimates in bDMARD-naïve patients with active PsA from the phase 3, pivotal BE OPTIMAL trial (NCT03895203). Methods BE OPTIMAL is a randomised multicentre, double-blind, PBO-controlled to wk 16, followed by 36-wks maintenance phase, active reference, parallel-group, phase 3 study. Patients were randomised (2:3:1) to receive PBO, BKZ 160 mg every 4 weeks (Q4W), or active reference (adalimumab [ADA]) 40 mg every 2 weeks (Q2W). At wk 16, patients receiving PBO were switched to BKZ 160 mg Q4W; other patients remained on their original dose. We report PsARC to wk 16 and wk 24, and the association of PsARC response with HRQoL-related outcomes for the randomised set. Data are reported as non-responder imputation (NRI) and observed cases. Results 852 patients were randomised at the baseline (PBO: 281; BKZ: 431; ADA: 140). Baseline characteristics were comparable between the three groups (mean age: 48.7 yrs; BMI: 29.20 kg/m2; disease duration: 5.9 yrs and 46.8% were males). At wk 16, PsARC response (NRI) was achieved by: PBO, 40.2%; BKZ, 80.3% and ADA, 82.1%. At wk 24, PsARC response increased in those PBO patients switched to BKZ: PBO/BKZ, 76.2%; BKZ, 77.3% and ADA, 80.0% (Table). Clinically meaningful improvement in HAQ-DI and SF-36 physical component summary (PCS), and improvements in FACIT-Fatigue were achieved from baseline among PsARC responders compared to non-responders (Table). Over the course of 24 weeks, safety was consistent with previous BKZ studies and no new safety signals were observed. Conclusion BKZ in bDMARD-naïve PsA patients demonstrated rapid and clinically relevant improvements in musculoskeletal outcomes compared to PBO at wk 16 and patients who switched to BKZ from PBO at wk 16 have a similar response rate at wk 24. Patients with PsARC response had numerically greater improvements in HRQoL-related outcomes. No new safety signals were observed. Disclosure I. McInnes: Grants/research support; IM has received grants/research support from Astra Zeneca, Abbvie, BMS, Compugen, Cabaletta, EveloBio, Eli Lilly, GSK, Janssen, Novartis, Moonlake, Novartis, Sanofi, UCB Pharma, XinThera. B. Ink: Shareholder/stock ownership; BI is a shareholder of AbbVie, GlaxoSmithKline and UCB Pharma. R. Bajracharya: Other; RB is an employee of UCB Pharma. V. Taieb: Other; VT is employee of UCB Pharma. W.R. Tillett: Other; WRT has received Research Grant, consulting or speaker fees from Abbvie, Amgen, Eli Lilly, Janssen, GSK, MSD, Novartis, OVA Pharma, Pfizer and UCB Pharma.