S1003 Endoscopic Severity, Unlike Histology, Is Associated With Increasing Age in EoE Pediatric, Adolescent, and Adult Patients at Baseline: Pooled Post-Hoc Analysis of Phase 3 KIDS and TREET Clinical Trials

Introduction: Eosinophilic esophagitis (EoE) is a type 2 inflammatory disease affecting the esophagus in all ages. Features of EoE improved significantly following dupilumab treatment, an antibody blocking Interleukin-4 and -13, confirming common pathophysiology across ages. Research suggests disease severity may differ by age. To assess this, we investigated associations between age and disease characteristics using combined data from 2 phase 3 trials. Methods: This is a post-hoc analysis from the EoE KIDS (NCT04394351) and LIBERTY EoE TREET (NCT03633617) trials. Non-age-based inclusion/exclusion criteria were similar, apart from a minimum dysphagia requirement in TREET, not required in KIDS. Patient demographics, prior treatments, and EoE disease characteristics were assessed in 3 subgroups: pediatric (≥1-<12 years); adolescent (≥12-<18 years); adult (≥18 years). Regression analyses using age as a continuous variable evaluated the impact of a 1-year increase in age on each variable. Parameter estimate size indicated the strength of the relationship; positive/negative indicated the direction of the association. Results: Younger age was associated with greater likelihood of male sex (parameter estimate: -0.024 [95% confidence interval: -0.037 to -0.010]; P < 0.001), having ≥1 concurrent type 2 inflammatory disease (-0.043 [-0.060 to -0.025]; P < 0.0001), and having a food elimination diet (-0.040 [-0.054 to -0.026]; P < 0.0001). Endoscopic severity, as assessed by Endoscopic Reference Score total score, increased with age (0.016 [0.006-0.026]; P < 0.01), but the relationship was not consistent across fibrostenotic and inflammatory subscores. Inflammatory features edema and exudates decreased with increasing age (-.004 [-0.006, -0.002]; P < 0.001, -0.008 [-0.006, -0.002]; P < 0.001, respectively), and fibrostenotic features rings and stricture increased with increasing age (0.023 [0.019, 0.028]; P < 0.0001, 0.008 [0.005, 0.010]; P < 0.0001). The likelihood of having a prior history of esophageal dilation also increased with increasing age (0.078 [0.060-0.095]; P < 0.0001). Histologic features were not significantly associated with age. Conclusion: In this pooled analysis of EoE KIDS and LIBERTY EoE TREET, associations between age and clinical/disease-related characteristics of EoE were observed. While baseline histologic features were similar across all ages, fibrostenotic endoscopic features and prior esophageal dilations were more common with increasing age, with inflammatory features more common in younger patients.