UCB trial puts Bimzelx ahead of AbbVie rival in arthritis duel

UCB has reported data it says marks a milestone in the crowded market for psoriatic arthritis treatments, with its drug bimekizumab beating AbbVie's risankizumab in a direct comparison of joint outcomes.

The week 16 results from the phase 3 BE BOLD trial, unveiled at the EULAR annual meeting in London, represent the first occasion an approved biologic has shown statistically significant superiority on joint outcomes in a head-to-head study in the disease, according to the Brussels-listed company.

The trial hit its primary endpoint, with 49.1 per cent of patients on bimekizumab — sold as Bimzelx — achieving an ACR50 response at week 16, against 38.4 per cent for those on risankizumab. The ACR50 measure denotes a 50 per cent improvement in disease symptoms.

The gap opened early. By week 4, some 19.9 per cent of bimekizumab patients had reached ACR50, compared with 7.2 per cent on the rival drug. On complete skin clearance at week 16, bimekizumab led 53.4 per cent to 46.6 per cent.

Results across secondary endpoints favoured bimekizumab numerically but did not clear the bar for statistical significance within the trial's prespecified testing sequence — a caveat that limits the strength of the broader claims.

Professor Iain McInnes of the University of Glasgow said high-level clinical responses were critical for patients, and that the head-to-head design could help clinicians make earlier, better-informed treatment decisions.

Emmanuel Caeymaex, executive vice-president at UCB, framed the trial as evidence to "inform the treatment landscape," arguing that head-to-head studies were the most rigorous form of comparative research.

On safety, the company said no new signals emerged. Candida infections were more common with bimekizumab but were mild or moderate and prompted no discontinuations, while treatment-emergent adverse events and dropout rates were broadly level between the two arms.

The findings sharpen a commercial contest between two of immunology's higher-profile assets, as UCB looks to expand Bimzelx's footprint across inflammatory diseases.