Belgium-based UCB said Wednesday its blockbuster anti-inflammatory drug Bimzelx beat AbbVie’s Skyrizi in a head-to-head trial for active psoriatic arthritis, potentially setting up Bimzelx for a boost in market share.
Bimzelx works by targeting an immune system-regulating protein known as IL-17. Specifically, it’s the only approved drug that blocks the “A” and “F” subtypes of IL-17. Skyrizi, meanwhile, blocks a closely related protein called IL-23.
According to UCB, Bimzelx topped Skyrizi by significantly alleviating disease symptoms after 16 weeks of treatment. The study’s main test was the “ACR50,” which defines a patient response as a 50% improvement in the number of tender and swollen joints, along with 50% improvements in at least a few other disease measures. Bimzelx, UCB said, is first approved biologic therapy to show superiority over an IL-23 inhibitor in psoriatic arthritis.
For years, drugmakers have been enticed by the promise that impairing IL-17 could treat a range of immunological conditions. Approved IL-17 inhibitors such as Novartis’ Cosentyx and Eli Lilly’s Taltz have become top-selling drugs for their respective companies. Bimzelx, which gained Food and Drug Administration approval in 2023, has also grown substantially since entering the market. Net sales of Bimzelx nearly quadrupled last year — to 2.2 billion euros or about $2.5 billion.
Yet, these drugs face competition from IL-23 blockers like Skyrizi and Johnson & Johnson’s Tremfya and Stelara.
UCB’s study, titled BE BOLD, is the fourth head-to-head study that showed Bimzelx’s superiority across psoriatic disease, and the first conducted in psoriatic arthritis. The trial enrolled 553 participants, who were randomized to receive either Bimzelx or Skyrizi.
UCB said full data will be presented at an international congress.
In a note to clients, Jefferies analyst Michael Leuchten wrote that UCB’s latest results were expected, given “IL-17 activity favours joints,” and the ACR50 endpoint at 16 weeks “structurally favours IL‑17 biology over IL‑23 inhibitors, especially in joint‑dominant disease.” The study is therefore “unlikely to materially influence” Bimzelx sales volumes in the near term.
Trung Huynh, an analyst at RBC Capital Markets, echoed that sentiment in his own note. "This news will cause short-term volatility to the stock, but AbbVie’s franchise remains defensible."
