First Tracks Biotherapeutics (TRAX) Study result summary

Study design and mechanism

• ANB033 is a subcutaneous CD122 antagonist designed to block IL-2 and IL-15 signaling in pathogenic immune-cell subsets.

• Phase 1b Cohort 1 randomized 32 participants (ANB033 17; placebo 15) 1:1; participants received 6 g gluten daily during Weeks 4–6, followed by Week 6 endoscopy.

• Week 6 endpoints included Vh:Cd ratio and IEL density; participants had symptom-controlled celiac disease and minimal mucosal damage.

Efficacy

• Week 6 LS mean Vh:Cd change was -0.17 with ANB033 vs. -0.66 with placebo; placebo-adjusted difference +0.49 (p=0.009), with ~75% less decline and change below the ~0.25 clinically meaningful threshold.

• IEL density change was -1.20 with ANB033 vs. +18.83 with placebo; treatment difference -20.03 (p<0.001). VCIEL treatment difference was +3.33 (p=0.002).

• ANB033 prevented symptom increases throughout the challenge; CDSD scores were significantly lower vs. placebo on Days 1–7, and moderate-to-severe symptoms were lower on Days 1–12.

• Permitted GI symptom medication was used by 6% of ANB033 participants vs. 47% on placebo.

Safety and tolerability

• In the safety set (n=34), any AE occurred in 88.9% with ANB033 vs. 100% with placebo; no serious AEs occurred in either arm.

• No severe AEs or AE-related discontinuations occurred with ANB033; one severe AE and one discontinuation occurred on placebo.

• Injection-site erythema occurred in 27.8% with ANB033 vs. 12.5% with placebo; nausea occurred in 5.6% vs. 43.8%.