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Primary endpoint showing superiority met: Bimekizumab achieved statistically significant superiority over risankizumab in reducing disease activity, as measured by the stringent ACR50 endpoint, at Week 16 in adults living with active psoriatic arthritis
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Landmark psoriatic arthritis (PsA) study: Bimekizumab is the first licensed biologic therapy to demonstrate superiority in psoriatic arthritis over an IL-23 inhibitor
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Fourth bimekizumab study showing superiority: BE BOLD is the fourth head-to-head study demonstrating superiority in the bimekizumab clinical trial program across psoriatic disease, and the first conducted in PsA
Brussels (Belgium), March 11, 2026 – 07:00 (CEST) – Regulated Information – Inside Information – UCB, a global biopharmaceutical company, today announced positive topline data from the BE BOLD trial assessing BIMZELX®▼(bimekizumab) versus SKYRIZI® (risankizumab) in adults living with active psoriatic arthritis (PsA). Bimekizumab, the first and only approved medicine to selectively inhibit both interleukin 17A (IL-17A) and interleukin 17F (IL-17F), demonstrated statistically significant superiority in the ACR50 primary efficacy endpoint at Week 16. Treatment with bimekizumab was generally well tolerated, with no new safety signals observed to Week 16.
“Our landmark BE BOLD study provides the first head-to-head evidence of superiority versus an IL-23 inhibitor in psoriatic arthritis. These topline results reinforce bimekizumab’s potential to deliver clinically meaningful improvements using the stringent ACR50 measure of disease activity, indicating more complete control of joint inflammation,” said Emmanuel Caeymaex, Executive Vice President, Head of Patient Evidence, UCB. “BE BOLD represents the fourth head-to-head study demonstrating bimekizumab superiority, supporting physicians to make informed treatment decisions and advancing our ambitions to raise the standard of care for people living with psoriatic disease.”
The results of BE BOLD add to the breadth of data for bimekizumab across a range of immune-mediated inflammatory diseases. UCB plans to submit the full BE BOLD results to a forthcoming international congress.
ACR50: A 50% or greater improvement from baseline in American College of Rheumatology response criteria, including at least a 50% improvement in tender and swollen joint counts as well as 50% improvement in three additional criteria (physician global, patient global, patient pain, function, and CRP/erythrocyte sedimentation rate).1 This represents a stringent efficacy outcome in psoriatic arthritis.2,3
About psoriatic arthritis
Psoriatic arthritis (PsA) is a serious, highly heterogeneous, chronic, systemic inflammatory condition affecting both the joints and skin with a prevalence of 0.02 percent to 0.25 percent of the population.4 Of people living with psoriasis, approximately 30 percent progress to also develop psoriatic arthritis.5 It manifests as joint pain and stiffness, skin plaques, swollen toes and fingers (dactylitis) and inflammation of the sites where tendons or ligaments insert into the bone (enthesitis).6 The burden on those living with PsA extends beyond physical discomfort to reduced quality of life, with comorbidities including hypertension, cardiovascular disease, anxiety, and depression.7 In PsA, uncontrolled active disease can lead to long-term structural damage.8
About the BE BOLD trial
BE BOLD is a multicenter, randomized, double-blind, risankizumab-controlled, parallel-group study designed to evaluate the efficacy and safety of bimekizumab in adult study participants (n=553) with active psoriatic arthritis (PsA).9 The study includes adults with active PsA who are naïve to biologic treatments or who had previous exposure to one tumor necrosis factor-inhibitor (TNFi) with an inadequate or intolerant response.9
The primary endpoint in BE BOLD is ACR50 at Week 16.9 The study has a double-blinded methodology until Week 24.10 In the study, participants were randomized 1:1 to receive either bimekizumab or risankizumab.10
For details about BE BOLD: https://clinicaltrials.gov/study/NCT0662422.
About BIMZELX®▼(bimekizumab) in the European Union (EU)/European Economic Area (EEA)
BIMZELX® is a humanized monoclonal IgG1 antibody that is designed to selectively inhibit both interleukin 17A (IL-17A) and interleukin 17F (IL-17F), two key cytokines driving inflammatory processes.11
About UCB
UCB, Brussels, Belgium (www.ucb.com) is a global biopharmaceutical company focused on the discovery and development of innovative medicines and solutions to transform the lives of people living with severe diseases of the immune system or of the central nervous system. With more than 9 000 people in approximately 40 countries, the company generated revenue of € 7.7 billion in 2025. UCB is listed on Euronext Brussels (symbol: UCB).
References
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Ritchlin CT, et al. Ann Rheum Dis. 2023;82(11);1404–14.
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Ogdie A, et al. Rheum Dis Clin North Am. 2015;41(4):545–68.
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About Psoriatic Arthritis. National Psoriasis Foundation. https://www.psoriasis.org/about-psoriatic-arthritis/. Last accessed: March 2026.
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Mease PJ, et al. Drugs. 2014;74(4):423–41.
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Lee S, et al. P T. 2010;35(12):680–9.
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Kwok TSH, et al. J Rheumatol. 2023;50(4):497–503.
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Clinical Trials.gov page. NCT06624228. https://www.clinicaltrials.gov/study/NCT06624228. Last accessed: March 2026.
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UCB. Data on file.
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BIMZELX® (bimekizumab) EU SmPC. https://www.ema.europa.eu/en/documents/product-information/bimzelx-epar-product-information_en.pdf. Last accessed: March 2026.
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BIMZELX® (bimekizumab) U.S. PI. https://www.ucb-usa.com/Innovation/Products/BIMZELX. Last accessed: March 2026.