BE BOLD Head-to-Head: IL-17 vs IL-23 for Psoriasis and PsA

In "BE BOLD Head-to-Head: IL-17 vs IL-23 for Psoriasis and PsA," the panel digs into the trial that broke the usual non-inferiority pattern.

Dr. Wright describes BE BOLD as a phase 3b head-to-head comparing bimekizumab, an IL-17A/F inhibitor, against risankizumab, an IL-23 inhibitor, in psoriatic arthritis. Skin burden was low, with baseline PASI around 3 rather than above 10, which changes how that measure performs. At week 16, roughly four months, bimekizumab reached ACR50 more often, 49% versus 38%, an 11-point split maintained through week 24.

Dr. Wright argues an 11% difference is meaningful, matching the ranges that separate drugs and ACR thresholds. On the stricter ACR50-plus-clear-skin endpoint, bimekizumab led numerically, 33.5% versus 24.4%, though not to statistical significance. Safety was comparable except for the candida infections expected with IL-17, which she frames as manageable and non-systemic. She calls it a win to finally differentiate pathways as better rather than merely non-inferior, in the same modern patient population rather than across separate trials.

Dr. Han says the design deliberately aimed for superiority, and existing skin data already show bimekizumab hitting the highest PASI 100 rates at earlier time points. He calls it the most well-rounded agent for patients bouncing between skin and joints, and credits the trial for going after risankizumab, a popular high-market-share drug, rather than a weaker comparator.

Dr. Han then discusses a 2026 retrospective analysis of a claims database suggesting IL-23s carried the lowest risk of developing psoriatic arthritis. He urges caution given methodological limits, such as billing artifacts, and the journal it landed in. He notes clinicians can reasonably start with the most effective option for both domains or defer it and switch later. He closes on candidiasis, noting most patients do not get recurrent episodes, and advises making decisions based on science rather than fear.

Our next episode, "IL-17 Inhibitor Safety in Psoriasis: Candidiasis, IBD, and Mental Health," turns to the safety profile of IL-17 inhibitors in depth, from candidiasis to inflammatory bowel disease and mental health.