Bimzelx Demonstrates Superior Joint Outcomes Over Risankizumab in Psoriatic Arthritis BE BOLD Trial

UCB announced new Phase 3 data showing that bimekizumab-bkzx (Bimzelx) achieved superior joint efficacy compared with risankizumab-rzaa (Skyrizi) in adults with active psoriatic arthritis (PsA), according to Week 16 results from the BE BOLD study presented ahead of the 2026 European Alliance of Associations for Rheumatology Annual Meeting.¹

The trial met its primary endpoint, with 49.1% of patients treated with Bimzelx achieving at least a 50% improvement in American College of Rheumatology response criteria (ACR50) at Week 16 compared with 38.4% of patients receiving Skyrizi (p=0.0078).¹

Psoriatic arthritis is a chronic inflammatory disease affecting both joints and skin, often associated with psoriasis and linked to long-term structural joint damage if left uncontrolled.²

Could head-to-head biologic data influence psoriatic arthritis treatment decisions?

According to UCB, BE BOLD is the first head-to-head PsA study involving an IL-23 inhibitor and the first approved biologic therapy to demonstrate statistically significant superiority on ACR50 joint outcomes in a direct comparison trial.¹

“Delivering high-level clinical responses is crucial for people with psoriatic arthritis,” said Iain McInnes, professor at the University of Glasgow College of Medical, Veterinary and Life Sciences, in the company announcement. “The new BE BOLD data, showing bimekizumab achieved superiority vs risankizumab in ACR50 at Week 16 in a direct head-to-head trial design, can support clinicians in making early informed decisions for treating this chronic inflammatory disease.”¹

Bimzelx also demonstrated numerically higher results across multiple secondary and exploratory endpoints, although not all achieved statistical significance because of the study’s prespecified testing hierarchy.¹ Minimal disease activity at Week 16 was reported in 43.0% of patients receiving Bimzelx compared with 39.9% receiving Skyrizi.¹

The study additionally showed faster onset of joint improvement with Bimzelx. At Week 4, 19.9% of patients receiving Bimzelx achieved ACR50 compared with 7.2% receiving Skyrizi.¹

How did Bimzelx perform on skin clearance and safety measures?

Among patients with psoriasis involving at least 3% body surface area at baseline, complete skin clearance measured by Psoriasis Area and Severity Index 100 occurred in 53.4% of patients treated with Bimzelx versus 46.6% receiving Skyrizi at Week 16.¹ However, the difference was not statistically significant.¹

Bimzelx is a monoclonal antibody designed to selectively inhibit both interleukin-17A and interleukin-17F, cytokines associated with inflammatory processes in psoriatic disease.³ Skyrizi targets interleukin-23.⁴

No new safety signals were identified during the study.¹ Rates of treatment-emergent adverse events were 57.0% in the Bimzelx group and 52.0% in the Skyrizi group.¹ Serious adverse events occurred in 1.8% and 2.9% of patients, respectively.¹ UCB noted that all Candida infections observed in the Bimzelx arm were mild or moderate and did not lead to treatment discontinuation.¹

The multicenter, randomized, double-blind BE BOLD study enrolled 553 adults with active PsA who were biologic-naïve or previously exposed to one tumor necrosis factor inhibitor with inadequate response or intolerance.⁵

References

1. BIMZELX demonstrates superior efficacy over SKYRIZI in psoriatic arthritis: BE BOLD Week 16 data. (2026 May 19). PR Newswire. https://www.prnewswire.com/news-releases/bimzelx-bimekizumab-bkzx-demonstrates-superior-efficacy-over-skyrizi-risankizumab-rzaa-in-psoriatic-arthritis-be-bold-week-16-data-302460220.html
2. About Psoriatic Arthritis. (2026). National Psoriasis Foundation. https://www.psoriasis.org/about-psoriatic-arthritis/
3. BIMZELX (bimekizumab-bkzx) prescribing information. UCB. Accessed May 20, 2026. https://www.ucb-usa.com/innovation/products/BIMZELX
4. SKYRIZI (risankizumab-rzaa) prescribing information. Abbvie. Accessed May 20, 2026. https://www.skyrizihcp.com/
5. A study to evaluate efficacy and safety of bimekizumab compared with risankizumab in participants with active psoriatic arthritis (BE BOLD). Clinicaltrials.gov. Accessed May 20, 2026. https://clinicaltrials.gov/study/NCT06624228