BRUSSELS, Belgium, May 19, 2026
UCB announced new Phase 3b clinical data showing that BIMZELX® (bimekizumab) demonstrated superior efficacy compared with SKYRIZI® (risankizumab) in adults with active psoriatic arthritis (PsA), marking a major milestone in the treatment landscape for chronic inflammatory diseases. The findings come from the company’s head-to-head BE BOLD trial, with results scheduled for presentation at the 2026 EULAR Annual Meeting in London. According to the Week 16 analysis, bimekizumab became the first approved biologic therapy to demonstrate statistically significant superiority in ACR50 joint outcomes in a direct comparison study for psoriatic arthritis.
The clinical study showed that 49.1% of patients receiving bimekizumab achieved the stringent ACR50 primary endpoint at Week 16, compared with 38.4% of patients treated with risankizumab. The improvement reached statistical significance and highlighted the strong joint symptom control achieved with the IL-17A and IL-17F inhibitor. Researchers noted that high-level ACR50 responses are considered clinically meaningful because they reflect substantial reductions in disease activity, inflammation, pain, and physical limitations associated with psoriatic arthritis.
BE BOLD Trial Demonstrates Strong Joint and Skin Responses
The multicenter, randomized, double-blind Phase 3b BE BOLD study evaluated the efficacy and safety of bimekizumab against risankizumab in 553 adults with active psoriatic arthritis. Participants included patients naïve to biologic treatment as well as individuals previously exposed to tumor necrosis factor inhibitors. The primary objective was to compare achievement of ACR50 at Week 16, one of the most demanding efficacy measures used in rheumatology clinical research.
Beyond the primary endpoint, the study also reported encouraging outcomes across several important secondary and exploratory endpoints. Investigators observed numerically higher responses for bimekizumab across multiple measures including minimal disease activity (MDA), simultaneous ACR50 plus PASI100, and DAPSA low disease activity/remission scores. Importantly, bimekizumab also demonstrated rapid onset of action, with 19.9% of patients achieving ACR50 by Week 4 compared with only 7.2% in the risankizumab treatment arm.
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Complete skin clearance outcomes were also highly notable. Among patients with significant psoriasis involvement at baseline, 53.4% treated with bimekizumab achieved PASI100, representing total skin clearance, versus 46.6% receiving risankizumab. These findings reinforce the therapy’s dual impact on both joint inflammation and skin disease, two major burdens experienced by people living with psoriatic arthritis.
Safety Profile Supports Long-Term Psoriatic Disease Management
Safety findings from the BE BOLD trial remained generally consistent with previously established bimekizumab clinical data. UCB reported that no new safety signals were identified during the study, and overall adverse event rates were comparable between treatment groups. While Candida infections occurred more frequently among patients receiving bimekizumab, all reported cases were mild or moderate in severity, with no systemic infections or treatment discontinuations linked to those events.
Researchers also observed low discontinuation rates due to treatment-emergent adverse events across both study arms. Serious adverse events remained infrequent, supporting the therapy’s manageable safety profile in this patient population. Healthcare experts believe these results may strengthen physician confidence in selecting bimekizumab for patients requiring aggressive disease control and rapid symptom improvement.
Psoriatic Arthritis Treatment Landscape Continues to Evolve
Psoriatic arthritis is a chronic systemic inflammatory disease affecting both joints and skin, often causing pain, stiffness, swelling, fatigue, and long-term structural joint damage if left uncontrolled. Approximately 30% of patients with psoriasis eventually develop psoriatic arthritis, creating significant quality-of-life burdens and increased risk of cardiovascular disease, anxiety, and depression.
Industry experts believe the BE BOLD results could influence future treatment strategies by providing clinicians with direct comparative evidence between major biologic therapies. Head-to-head studies remain relatively uncommon in rheumatology, making the findings especially valuable for treatment decision-making in increasingly competitive immunology markets.
UCB noted that the BE BOLD data are part of a broader immunology portfolio presentation at EULAR 2026, where the company will present 27 scientific abstracts covering psoriatic arthritis, psoriasis, rheumatoid arthritis, lupus, and axial spondyloarthritis. The company continues expanding BIMZELX’s role across multiple inflammatory diseases globally.
Source: UCB, BIMZELX press release
