argenx Phase 2 data back FB102 as first drug for celiac disease
argenx has reported positive topline results from a Phase 2 study of FB102, its investigational anti-CD122 monoclonal antibody, in adults with celiac disease. The trial met its primary endpoint, a statistically significant improvement in the villus height-to-crypt depth ratio at day 78 compared with placebo (p=0.0176), a histological measure of intestinal damage caused by gluten exposure. The company said it will advance FB102 into Phase 3 development.
The study, designated FB102-301, enrolled 126 patients with confirmed celiac disease who had been symptom-free on a strict gluten-free diet for at least 12 months. Participants were randomised at a 2:2:1 ratio to receive one of two intravenous dose levels of FB102 or placebo across an eight-week controlled oral gluten challenge. Secondary measures including intraepithelial lymphocyte density and a composite histological and inflammatory score moved in directions consistent with the primary result, and argenx reported no new safety signals.
Mechanism and broader pipeline context
FB102 targets CD122, a shared subunit of the interleukin-2 and interleukin-15 signalling receptors. Blocking CD122 is intended to suppress the activation of disease-driving immune cells in the intestinal mucosa while leaving regulatory T-cell function largely intact. Luc Truyen, Chief Medical Officer at argenx, said the Phase 2 findings build on earlier Phase 1b data and confirm that CD122 blockade can "protect against gluten-induced intestinal damage and prevent emergence of patient symptoms, even under a more intense gluten challenge." Full results are expected to be presented at an upcoming medical meeting.
FB102 entered the argenx portfolio in August 2026 through the acquisition of Forte Biosciences, and it carries FDA Fast Track Designation for the celiac disease indication. Beyond celiac disease, argenx is evaluating the antibody in vitiligo and alopecia areata, two additional immune-mediated dermatological conditions that share overlapping IL-15-driven pathology.
Competitive and regulatory landscape
Celiac disease affects an estimated one percent of the global population, with incidence reported to be growing at roughly 7.5 percent per year. Despite that prevalence and burden, no pharmaceutical therapy has received regulatory approval in the indication; strict gluten avoidance remains the only standard of care. That unmet-need profile has drawn increasing attention from the immunology sector, with several companies including Takeda, Provention Bio (now part of Sanofi), and a number of earlier-stage biotechs exploring transglutaminase inhibitors, tight-junction modulators and tolerogenic approaches. None has yet reached late-stage pivotal data.
argenx occupies an advantageous position given its established commercial and regulatory infrastructure built around efgartigimod, the first approved FcRn blocker, which it markets across multiple autoimmune indications. That infrastructure should reduce the friction of designing a global Phase 3 programme and navigating interactions with the FDA and EMA. The key questions for investors ahead of Phase 3 will be the dose selected, the chosen primary endpoint in a confirmatory trial, and whether argenx pursues a gluten-challenge model or an unrestricted-diet design that better reflects real-world exposure. Detailed data at an upcoming conference will be watched closely for the magnitude of the Vh:Cd improvement and for any divergence in response between the two dose cohorts.