Blocking Gluten-Induced Intestinal Damage: Early Celiac Disease Trial Shows Protective Signal for ANB033

For patients with celiac disease, accidental gluten ingestion can still cause symptoms and intestinal damage despite efforts to avoid it. On October 12, First Tracks Biotherapeutics announced results from a Phase 1b trial: after consuming gluten for two consecutive weeks, patients receiving the experimental antibody ANB033 had better outcomes than the placebo group on both intestinal tissue damage and symptom measures, providing preliminary evidence of whether the drug could offer additional protection.

ANB033 targets CD122, the β subunit shared by the IL-15 and IL-2 receptors. This subcutaneously injected antibody aims to block two immune signaling pathways and reduce the activity of immune cells associated with intestinal inflammation. The study therefore tracked both intestinal tissue changes and patients’ experiences to examine whether biological effects were accompanied by differences in symptoms.

The first study cohort reported included 32 patients who completed dosing and the gluten challenge and were evaluable for efficacy, with 17 receiving ANB033 and 15 receiving placebo. Both groups received injections at weeks 0, 2, and 4 and underwent a 14-day gluten challenge of 6 grams per day. This controlled exposure helps compare the drug’s effects, but it still differs from occasional accidental gluten ingestion in daily life.

At week 6, the drug group had a smaller decline in the ratio of intestinal villous height to crypt depth, indicating less damage to intestinal structure; intraepithelial lymphocyte density and another composite tissue measure also showed statistically significant differences between groups. Beyond the tissue findings, Benzinga’s reporting on the same day also confirmed that total symptom diary scores were lower on challenge days 1 through 7, and moderate to severe symptoms were less frequent on days 1 through 12; the proportions using study-permitted medication to relieve gastrointestinal symptoms were 6% and 47% in the two groups, respectively.

The safety data require careful distinction between the numbers analyzed and the treatment groups. The announced safety analysis included 34 people, and the ANB033 group had no serious adverse events, severe adverse events, or treatment discontinuations due to adverse events. However, 16 of the 18 patients receiving the drug still reported at least one adverse event, with injection-site erythema among the common reactions. The absence of major warning signs in the short term is not sufficient to establish long-term safety.

The current evidence comes from preliminary results released by the company, and media reports on the same day were also based primarily on that announcement, rather than on another independent study. Given the small sample, short observation period, and statistical significance of symptom differences concentrated on specific days, these findings cannot be extrapolated to sustained, comprehensive symptom control, nor can they establish that patients can now relax their dietary restrictions.

First Tracks expects to initiate late-stage clinical trials in celiac disease in 2027, with specific plans still subject to discussions with regulators. Preliminary data from another Phase 1b study cohort evaluating mucosal healing over 12 weeks are expected in the first quarter of 2027. The key next step is to determine whether the protective signal seen in this gluten challenge can be reproduced over a longer period and in a broader patient population.