Objective: The objective of this study was to assess 52-week efficacy and safety of bimekizumab in patients with active psoriatic arthritis (PsA) with or without concomitant methotrexate (+/-MTX) treatment at baseline. Methods: We conducted a post hoc analysis of patients in BE OPTIMAL (NCT03895203; biologic disease-modifying antirheumatic drug [bDMARD]-naïve), BE COMPLETE (NCT03896581; prior inadequate response or intolerance to tumor necrosis factor inhibitors [TNFi-IR]), and the BE VITAL open-label extension (NCT04009499) study. Patients were randomized to one of the following treatment groups: bimekizumab 160 mg every four weeks, placebo, or a reference drug (adalimumab 40 mg every two weeks; BE OPTIMAL only). From Week 16, placebo-randomized patients received bimekizumab. Missing data were imputed using non-responder imputation, multiple imputation, or worst-category imputation. Results: Through Week 52, similar proportions of bimekizumab-treated patients achieved American College of Rheumatology 50% (ACR50) response criteria for both +MTX and -MTX (BE OPTIMAL: 54.4% +MTX, 54.7% -MTX; BE COMPLETE: 56.3% +MTX, 48.0% -MTX). Similar proportions of bimekizumab-treated patients achieved complete skin clearance (Psoriasis Area and Severity Index 100% [PASI100] response) and minimal disease activity in both +MTX and -MTX groups. Similar trends were seen in placebo/bimekizumab-treated patients. Through Week 52, the proportion of bimekizumab-treated patients with ≥1 treatment-emergent adverse event were similar between the +MTX and -MTX groups (BE OPTIMAL 325 of 410 [79.3%] vs 230 of 292 [78.8%], BE COMPLETE 105 of 168 [62.5%] vs 138 of 220 [62.7%]). The safety profile was comparable between subgroups and consistent with the prior safety profile of bimekizumab. Conclusion: Treatment with bimekizumab demonstrated consistent, sustained efficacy to 52 weeks in bDMARD-naïve and TNFi-IR patients with PsA and was well tolerated, irrespective of concomitant MTX.