UCB Reports 24-Week Bimekizumab (Bimzelx) vs Risankizumab Data in PsA

UCB announced on November 9, 2026, 24-week results from the phase 3b BE BOLD trial. They show that bimekizumab-bkzx (Bimzelx) kept numerically greater joint responses than risankizumab (Skyrizi) in adults with active psoriatic arthritis (PsA), building on the statistically significant superiority it showed at week 16.¹ At week 24, 54.9% of patients receiving bimekizumab achieved ACR50 vs 43.8% of those receiving risankizumab, an exploratory, nominally significant end point.¹ The full results are being presented at the 2026 ACR Convergence in Orlando, Florida, with an oral presentation scheduled for November 10.¹

“ACR50 is the new standard in PsA, reflecting considerable joint improvements and is known to be associated with clinically meaningful reductions in disease activity and subsequent improvements in quality of life,” said Joseph F. Merola, MD, MMSc, rheumatologist, dermatologist, president of the Psoriasis and Psoriatic Arthritis Multicenter Advancement Network, in a company press release.¹

What did the trial show at weeks 16 and 24?

Bimekizumab met the primary end point, in which 49.1% of patients achieved ACR50 at week 16 vs 38.0% of those receiving risankizumab, a difference of 11.1% (p=.0058).¹ Those week 16 results were first presented at the EULAR 2026 annual congress in June.² ACR50 responses favored bimekizumab at every study visit, beginning as early as week 4 (nominal p<.0001).¹

Minimal disease activity (MDA) at week 16, the first ranked secondary end point, was 3.4 percentage points higher with bimekizumab but was not statistically significant (p=.3921). Sequential testing stopped there, so later ranked secondary end points are descriptive only.¹ Numerically greater responses across joint, skin, and overall disease activity measures were sustained to week 24.¹

How did skin outcomes compare?

Among patients with psoriasis affecting at least 3% of body surface area at baseline, 12.5% receiving bimekizumab achieved complete skin clearance (PASI100) at week 4 vs 3.4% receiving risankizumab (nominal p<.01).¹ At week 16, rates were 53.4% vs 46.6%, without nominal significance. By week 24 they were comparable, at 59.7% and 59.1%.¹

What were the safety findings?

Through the data cutoff, 58.1% (161/277) of bimekizumab-treated and 55.3% (152/275) of risankizumab-treated patients had at least 1 treatment-emergent adverse event (TEAE).¹ Serious TEAEs occurred in 5 patients (1.8%) receiving bimekizumab and 9 (3.3%) receiving risankizumab. One death in the risankizumab arm was deemed unrelated to treatment.¹ Candida infections were more frequent with bimekizumab (2.9% vs 0.7%), consistent with its mechanism of action. All were mild or moderate, and none led to discontinuation.¹

Why does this head-to-head comparison matter?

Bimekizumab selectively inhibits both interleukin 17A (IL-17A) and IL-17F, whereas risankizumab inhibits IL-23, making BE BOLD a direct comparison of 2 distinct cytokine pathways in PsA.¹ The double-blind trial randomized 553 adults 1:1. Participants were biologic-naive or had an inadequate response or intolerance to 1 tumor necrosis factor inhibitor.¹^,³ Patients with no or mild psoriasis received bimekizumab 160 mg every 4 weeks. Those with moderate or severe psoriasis received 320 mg every 4 weeks to week 16, then every 8 weeks. Risankizumab was given at 150 mg at baseline, week 4, and week 16.¹

What are the limitations?

The week 24 ACR50 and PASI100 comparisons are exploratory and only nominally significant, and secondary end points after MDA are descriptive because hierarchical testing stopped. The data come from a conference abstract and have not been published in a peer-reviewed journal. BE BOLD was not powered to compare safety, and blinding extends only through week 24, so how long the differences last in direct comparison is unknown. The week 16 figures in this release (38.0% for risankizumab; p=.0058) differ slightly from those UCB reported in May 2026 (38.4%; p=.0078). The current release states that its data are based on the ACR abstract dataset.¹^,²

References

1. UCB. BE BOLD: Bimzelx (bimekizumab-bkzx) builds on superior joint responses versus Skyrizi (risankizumab) at Week 16, with clinical improvements sustained through Week 24. Press release. Published November 9, 2026. Accessed November 9, 2026. https://www.ucb.com/newsroom/press-releases/article/be-bold-bimzelxr-bimekizumab-bkzx-builds-on-superior-joint-responses-versus-skyrizir-risankizumab-at-week-16-with-clinical-improvements-sustained-through-week-24
2. UCB. Bimzelx (bimekizumab) demonstrates superior efficacy over Skyrizi (risankizumab) in psoriatic arthritis: BE BOLD Week 16 data. Press release. Published May 19, 2026. Accessed November 9, 2026. https://www.ucb.com/newsroom/press-releases/article/bimzelxrbimekizumab-demonstrates-superior-efficacy-over-skyrizir-risankizumab-in-psoriatic-arthritis-be-bold-week-16-data
3. A study to evaluate the efficacy and safety of bimekizumab in adult study participants with active psoriatic arthritis. ClinicalTrials.gov; NCT06624228. Updated September 2, 2026. Accessed November 9, 2026. https://clinicaltrials.gov/study/NCT06624228