argenx reports positive Phase 2 results for FB102 in celiac disease, with the CD122 inhibitor meeting its primary endpoint and Phase 3 planned.
Written By: Charvi Kalal, PharmD
Reviewed By: Pharmacally Editorial Team
argenx SE announced on October 8, 2026, positive topline results from its Phase 2 study of FB102, a first-in-class CD122 inhibitor, in adults with celiac disease. The randomized, double-blind, placebo-controlled FB102-301 study met its primary endpoint, showing a statistically significant treatment effect on the change in the villus height-to-crypt depth (Vh) ratio after an eight-week controlled gluten challenge. The company plans to advance FB102 into Phase 3 development. This represents the first major clinical readout for FB102 since argenx completed its acquisition of Forte Biosciences in August 2026.
Celiac Disease Remains an Unmet Medical Need
Celiac disease is a chronic autoimmune condition in which gluten, a group of proteins found in wheat, barley and rye, triggers an immune response that damages the lining of the small intestine. Persistent intestinal injury can impair nutrient absorption and cause symptoms including abdominal pain, bloating, diarrhea and fatigue.
argenx estimates that approximately 1% of people worldwide have celiac disease and that its incidence is increasing by about 7.5% annually. There are currently no approved medicines specifically for celiac disease. A strict gluten-free diet remains the standard of care, but unintended gluten exposure remains a common challenge.
FB102 Targets the CD122 Pathway
FB102 is an investigational anti-CD122 antibody designed to modulate signaling through interleukin-2 (IL-2) and interleukin-15 (IL-15), pathways involved in the activation and maintenance of disease-driving immune cells.
By targeting CD122, FB102 is designed to dampen these inflammatory pathways while preserving regulatory T-cell function and overall immune balance. The U.S. Food and Drug Administration has granted FB102 Fast Track Designation for celiac disease.
The antibody is also being investigated in other immune-mediated conditions, including vitiligo and alopecia areata.
Phase 2 Study Evaluated Protection During Gluten Challenge
The Phase 2 FB102-301 study (NCT06982963) enrolled 126 adults with confirmed celiac disease who had remained symptom-free while following a strict gluten-free diet for at least 12 months.
Participants were randomized in a 2:2:1 ratio to receive intravenous FB102 at one of two dose levels or placebo during a controlled eight-week oral gluten challenge.
The primary endpoint was the change from baseline in the villus height-to-crypt depth ratio at Day 78 compared with placebo. The Vh ratio is an established histologic measure of intestinal mucosal injury, with a lower ratio reflecting greater villous blunting and intestinal damage.
FB102 Meets Primary Endpoint
The study met its primary endpoint with a p-value of 0.0176, demonstrating a statistically significant treatment effect versus placebo.
Other efficacy measures were also consistent with the primary endpoint, including intraepithelial lymphocyte (IEL) density, the villus height-to-crypt depth/intraepithelial lymphocyte (VCIEL) composite score and symptoms. Together, these findings indicate activity across measures of intestinal tissue injury, inflammation and clinical symptoms.
argenx reported that the safety profile was consistent with previous studies and that no new safety signals were identified.
However, the company has not yet disclosed the numerical size of the treatment effect, dose-specific results or detailed results for the secondary efficacy measures. Full Phase 2 data are expected to be presented at an upcoming medical meeting.
Results Extend Earlier Phase 1b Findings
The Phase 2 findings build on earlier clinical data generated by Forte Biosciences.
In the Phase 1b study, which included 32 participants, Forte reported a 73% improvement in Vh compared with placebo and 42% fewer gluten-induced symptom events during a 16-day gluten challenge.
The Phase 2 study extended the evaluation to 126 participants and used a substantially longer eight-week gluten challenge. The positive Phase 2 topline result therefore supports the earlier evidence that CD122 inhibition may help limit gluten-induced intestinal injury and symptoms under controlled exposure.
First Major FB102 Readout Following Forte Acquisition
The Phase 2 results are the first major clinical update on FB102 since argenx acquired Forte Biosciences.
argenx agreed in July 2026 to acquire Forte for $77 per share in cash, representing approximately $2.2 billion in equity value. The transaction was completed on August 27, 2026, adding FB102 to argenx’s immunology pipeline.
The acquisition also expanded the potential development scope of FB102 beyond celiac disease, with the antibody being evaluated in additional immune-mediated diseases.
Phase 3 Development Planned
argenx plans to advance FB102 into Phase 3 development in celiac disease based on the Phase 2 findings.
The company has characterized the results as evidence that CD122 blockade can protect against gluten-induced intestinal damage and prevent symptoms during controlled gluten exposure. The upcoming detailed Phase 2 dataset will be important for assessing the magnitude and consistency of the treatment effect, dose-response relationships and the broader safety profile.
The study’s controlled gluten challenge is also an important consideration when interpreting the findings. Participants had well-controlled disease before undergoing intentional gluten exposure, which differs from the accidental or intermittent gluten exposure encountered in routine life.
FB102 is administered by intravenous infusion and remains investigational. It is not approved for the treatment of celiac disease or any other condition. The planned Phase 3 program and future development statements remain subject to further clinical evaluation.
Reference
argenx Announces Positive Topline Results from Phase 2 Study of FB102 in Celiac Disease, argenx, 08 October 2026
Randomized, Double Blind, Placebo-controlled Phase 2 Study in Adults with Celiac Disease, ClinicalTrials.gov ID NCT06982963
About the Writer
Charvi Kalal (LinkedIn) is a Pharm.D intern and aspiring medical writer with hands-on experience in medical writing, clinical research, pharmacovigilance, and clinical pharmacy. She has experience in medical content writing through CliMed, along with exposure to ADR monitoring, prescription analysis, patient counselling, literature review, and research documentation. Her research focuses on ADR monitoring and reporting in breast cancer patients receiving targeted therapy. With certifications in GCP, biomedical research, scientific writing, and clinical research, she is passionate about transforming scientific evidence into accurate, engaging, and accessible healthcare content.