Abstract Background/Aims Bimekizumab (BKZ), a humanised monoclonal IgG1 antibody that inhibits IL-17A and IL-17F, has demonstrated rapid efficacy in joint and skin outcomes for patients with active psoriatic arthritis (PsA) who are bDMARD-naïve (BE OPTIMAL; NCT03895203) and TNFi-inadequate responders (TNFi-IR) (BE COMPLETE; NCT03896581). Here we report longer-term PsA response criteria (PsARC) response, along with health-related quality of life (HRQoL) outcomes in BE OPTIMAL and BE COMPLETE. Methods BE OPTIMAL and BE COMPLETE were randomised multicentre, double-blind, placebo (PBO)-controlled, parallel-group, phase 3 trials. BE OPTIMAL included a 16-week (Wk) double-blind, PBO-controlled period and a 36-Wk active-treatment period. Patients were randomised (3:2) to receive BKZ 160mg Q4W, or PBO. At Wk16, PBO patients switched to BKZ. In BE COMPLETE, patients with inadequate response or intolerance to TNFis were randomised (2:1) to receive either BKZ 160mg Q4W or PBO for 16Wks after which they were eligible for entry into BE VITAL (NCT04009499; open-label extension). We report PsARC response rates at Wk52 (BE OPTIMAL) and Wk40 (BE COMPLETE). Additionally, the association of PsARC responders with HRQoL-related outcomes (HAQ-DI, FACIT-Fatigue and SF-36) for the randomised set are also reported. Data are reported as non-responder imputation (NRI) and observed cases (OC). Results In BE OPTIMAL, 821/852 (96.4%) patients completed Wk16 and 761 (89.3%) completed Wk52. In BE COMPLETE, 388/400 (97%) patients completed Wk16, 377 (94.3%) entered BE VITAL and 360 (90.0%) completed Wk40. Baseline characteristics were comparable between groups within both trials. In BE OPTIMAL, PsARC response (NRI) was achieved by 80.3% BKZ and 40.2% PBO patients at Wk16 and was sustained or increased at Wk52 to 79.1% BKZ and 79.7% PBO/BKZ patients. In BE COMPLETE, PsARC response (NRI) was achieved by 85.4% BKZ and 30.8% PBO at Wk16 and was sustained or increased at Wk40 to 77.9% BKZ and 75.2% PBO/BKZ patients. Clinically meaningful improvements in HAQ-DI and SF 36-PCS scores, and FACIT-Fatigue were achieved from baseline among PsARC responders compared to non-responders (Table). Conclusion Improvements in PsARC were sustained up to 1 year in BKZ-treated patients and associated with improvement in HRQoL and fatigue, regardless of whether patients were bDMARD-naïve (BE OPTIMAL) or TNFi-IR (BE COMPLETE). Disclosure W.R. Tillett: Other; WRT has received Research funding, consulting and or speaker fees from: Abbvie, Amgen, Eli Lilly, Janssen, Novartis, Pfizer and UCB Pharma. B. Ink: Shareholder/stock ownership; BI is a shareholder of AbbVie, GlaxoSmithKline and UCB Pharma. R. Bajracharya: Other; RB is an employee and shareholder of UCB Pharma. V. Taieb: Other; VT is an employee of UCB Pharma. P. Sharma: Other; PS has done Advisory Board for UCB Pharma. D. McGonagle: Grants/research support; DM has received research grants/research support from AbbVie, Celgene, Janssen, Merck, and, Pfizer. Other; DM has received honoraria or consultation fees and has been paid as a speaker for AbbVie, Celgene, Janssen, Merck, Novartis, Pfizer, and UCB Pharma. L.C. Coates: Consultancies; LCC has worked as a paid consultant for AbbVie, Amgen, Bristol Myers Squibb, Celgene, Eli Lilly, Gilead, Galapagos, Janssen, Moonlake, Novartis, Pfizer and UCB Pharma. Grants/research support; LCC has received grants/research support from AbbVie, Amgen, Celgene, Eli Lilly, Janssen, Novartis, Pfizer and UCB Pharma. Other; LCC has been paid as a speaker for AbbVie, Amgen, Biogen, Celgene, Eli Lilly, Galapagos, Gilead, GSK, Janssen, Medac, Novartis, Pfizer and UCB Pharma. I.B. 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.