UCB, a pharmaceutical company, has shared new results from a major clinical trial called the BE BOLD study. The trial compared two medications, bimekizumab and risankizumab, in adults with active psoriatic arthritis—a type of arthritis that often affects people with psoriasis. The findings show that bimekizumab worked better than risankizumab in improving joint symptoms after 16 weeks of treatment.
These results were presented at the 2026 EULAR Annual Meeting in London, marking the first time a biologic medication (a type of drug made from living cells) has clearly shown better joint improvement than another in a direct head-to-head study for psoriatic arthritis.
By week 16, nearly half (49.1%) of patients taking bimekizumab saw significant improvement in their joints, compared to about 38.4% of those taking risankizumab. The study also looked at other measures of improvement, such as skin clearance and overall disease activity, though these did not reach statistical significance in the way the researchers had planned. Still, bimekizumab showed numerically better results across all secondary measures.
Professor Iain McInnes from the University of Glasgow explained, ‘For people with psoriatic arthritis, achieving a strong clinical response is very important. The ACR50 level—meaning a 50% improvement in joint symptoms—shows meaningful reductions in disease activity, inflammation, and better quality of life.’
Emmanuel Caeymaex, an executive at UCB, said, ‘We are excited to share these results, which show bimekizumab is more effective than risankizumab in improving joint outcomes. Head-to-head trials like this provide the strongest evidence for comparing treatments, helping doctors and patients make informed decisions about managing psoriatic arthritis.’
The study also found that joint improvements with bimekizumab started as early as week 4. By this time, 19.9% of patients on bimekizumab saw significant joint improvement, compared to 7.2% on risankizumab. Additionally, 53.4% of those on bimekizumab achieved complete skin clearance (no visible psoriasis) by week 16, compared to 46.6% on risankizumab.
The safety of both medications was similar, with no new concerns identified. While more patients on bimekizumab had mild or moderate yeast infections (like thrush), none were serious enough to stop treatment. Side effects and the number of patients who stopped treatment were low and nearly the same for both groups.