UCB: Bimzelx Retains Its Edge Over Skyrizi at 24 Weeks, on an Exploratory Endpoint
UCB published on November 9, 2026 the 24-week data from BE BOLD, a Phase 3b head-to-head trial comparing its treatment directly with risankizumab in psoriatic arthritis, presented at ACR Convergence 2026 in Orlando.
The advantage in favor of bimekizumab on joint response persists, but it now rests on an exploratory endpoint, and no secondary endpoint reaches statistical significance.
Primary Endpoint Met at 16 Weeks, Exploratory Advantage at 24 Weeks
BE BOLD's primary endpoint, the ACR50 response at week 16, had already been published: UCB had then reported a statistically significant superiority of Bimzelx (bimekizumab) over Skyrizi (risankizumab). At week 24, 54.9% of patients treated with bimekizumab achieved ACR50, compared with 43.8% under risankizumab.
This week 24 result is an exploratory endpoint, described by the company as nominally significant. The data are analyzed using non-responder imputation, based on 277 patients in the bimekizumab group and 276 in the risankizumab group.
The study, conducted in a double-blind manner through week 24, included 553 adults with active psoriatic arthritis, either biologic-naïve or having previously received an anti-TNF with an insufficient response or intolerance. For rheumatologist and dermatologist Joseph F. Merola, “ACR50 is the new standard in psoriatic arthritis.”
Secondary Endpoints Not Significant, More Frequent Candida Infections
Across all secondary endpoints, responses under bimekizumab remain numerically higher through week 24, without reaching statistical significance. For complete clearance of skin lesions (PASI100, an exploratory endpoint), the numerical advantage observed from week 4 to week 16 gives way to comparable rates at weeks 20 and 24.
This skin measure concerns a subgroup of patients whose psoriasis covered at least 3% of body surface area at baseline, i.e., 176 patients per arm. Adverse events occurring during treatment are considered comparable between the two arms, except for localized Candida infections, mild to moderate, which were more frequent under bimekizumab.
The trial, however, did not have the statistical power required to compare the safety of the two treatments. Donatello Crocetta, Medical Director of UCB, believes these results “help redefine treatment expectations for people living with psoriatic arthritis.”
Full results will be presented orally on November 10 at 10:15 a.m. Eastern Time. They are among 18 abstracts presented by UCB at ACR Convergence, covering psoriatic arthritis, axial spondyloarthritis, rheumatoid arthritis and systemic lupus erythematosus.
