Atlanta, Georgia, United States, November 9, 2026

UCB, a global biopharmaceutical company, has announced additional Week 24 findings from its BE BOLD Phase 3b clinical trial, showing that BIMZELX® (bimekizumab-bkzx) maintained numerically higher joint response rates than SKYRIZI® (risankizumab-rzaa) in adults with active psoriatic arthritis (PsA). The results build on the previously reported Week 16 findings, when BIMZELX demonstrated statistically significant superiority over risankizumab for the primary endpoint of ACR50 response. At Week 24, 54.9% of patients receiving BIMZELX achieved an ACR50 response, compared with 43.8% of those receiving risankizumab. The findings were announced on November 9, 2026, ahead of their presentation at the 2026 American College of Rheumatology (ACR) Convergence in Orlando, Florida. The data provide further insight into the comparative performance of two targeted biologic therapies used to manage inflammatory joint disease and associated skin symptoms. UCB also reported improvements across several secondary disease measures, although these comparisons were numerical and did not establish statistical superiority at Week 24.

BE BOLD Trial Demonstrates Sustained Joint Responses

The BE BOLD study is a multicenter, randomized, double-blind, active-controlled Phase 3b clinical trial involving 553 adults with active psoriatic arthritis. Participants were either biologic-treatment naïve or had previously received one tumour necrosis factor inhibitor with an inadequate response or intolerance. The study compared BIMZELX with risankizumab, an interleukin-23 inhibitor, to evaluate their efficacy and safety in this patient population. The primary endpoint was the proportion of participants achieving an ACR50 response at Week 16. This measure represents at least a 50% improvement in tender and swollen joint counts, together with improvements in additional disease-related assessments, including pain, physical function and inflammatory markers. At Week 16, 49.1% of participants receiving BIMZELX achieved ACR50, compared with 38.0% receiving risankizumab. The 11.1-percentage-point difference was statistically significant, with a p-value of 0.0058. At Week 24, the response rates increased to 54.9% for BIMZELX and 43.8% for risankizumab. Higher ACR50 response rates were reported with BIMZELX at every assessed time point, beginning as early as Week 4. These findings indicate that the joint response advantage observed at Week 16 was maintained through Week 24, although the later comparison was reported as numerical.

Skin Clearance and Secondary Disease Outcomes

In addition to joint improvements, the BE BOLD trial evaluated secondary measures covering skin symptoms, overall disease activity and minimal disease activity (MDA). UCB reported numerically greater responses with BIMZELX across several secondary endpoints through Week 24. However, the first ranked secondary endpoint, MDA at Week 16, showed a difference of 3.4 percentage points that was not statistically significant. Because sequential statistical testing stopped at this point, subsequent ranked secondary endpoints were descriptive rather than confirmatory. The study also assessed complete skin clearance using the PASI100 measure in a subgroup of participants with psoriasis affecting at least 3% of their body surface area at baseline. At Week 4, PASI100 was achieved by 12.5% of participants receiving BIMZELX compared with 3.4% receiving risankizumab. At Week 16, the corresponding rates were 53.4% and 46.6%. By Week 24, complete skin clearance rates were comparable, at 59.7% and 59.1%, respectively. These findings highlight the importance of evaluating both joint and skin manifestations when assessing treatments for psoriatic arthritis, a chronic inflammatory condition that can affect multiple aspects of patients’ health and daily activities.

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Safety Findings and Clinical Significance

The overall treatment-emergent adverse event rates were comparable between the two treatment groups. At least one treatment-emergent adverse event was reported in 58.1% of BIMZELX-treated participants and 55.3% of those receiving risankizumab. No new safety signals were identified through Week 24, and serious adverse events were reported in 1.8% and 3.3% of the respective groups. One notable difference was the frequency of localized Candida infections, which occurred in 2.9% of participants receiving BIMZELX compared with 0.7% receiving risankizumab. These infections were mild or moderate, with none reported as serious, systemic or leading to treatment discontinuation. The study was not designed or powered to establish comparative safety superiority. BIMZELX is a dual IL-17A and IL-17F inhibitor, targeting two inflammatory cytokines involved in psoriasis and psoriatic arthritis. SKYRIZI works by inhibiting IL-23, another pathway involved in inflammatory disease. UCB presented the Week 24 findings as part of its wider immunology research programme at ACR Convergence 2026. The results add to clinical evidence comparing targeted biologic treatments, while longer-term evaluation will help establish the durability of treatment responses and safety in people living with psoriatic arthritis.

Source: UCB press release