579. DUPILUMAB IMPROVES ENDOSCOPIC FEATURES OF EOSINOPHILIC OESOPHAGITIS IN CHILDREN WITH EOSINOPHILIC OESOPHAGITIS: 52-WEEK ANALYSIS OF THE EOE KIDS STUDY

Abstract Introduction Eosinophilic oesophagitis (EoE) is a chronic type 2 inflammatory disease. Dupilumab, a fully human monoclonal antibody that blocks drivers of type 2 inflammation, is approved in the USA for EoE patients aged ≥1 year, weighing ≥15 kg, and in the EU for adult and adolescent EoE patients aged ≥12 years, weighing ≥40 kg. The EoE-Endoscopic Reference Score (EREFS) is a validated tool for assessing oesophageal features of EoE, with subscores for inflammation and remodelling. This study assessed the impact of dupilumab on EREFS in children aged 1–<12 years with active EoE in the phase 3 EoE KIDS trial. Methods In Part A, 102 patients (mean [SD] age: 7.1 [3.05] years) were randomised 2:2:1:1 to receive weight-tiered dupilumab higher-exposure (HE) or lower-exposure, or placebo (two groups) for 16 weeks. In Part B, all patients received dupilumab at their preassigned dupilumab regimen for a further 36 weeks. This analysis focused on the dupilumab HE and placebo groups. EREFS were scored centrally by reviewers blinded to both treatment allocation and time point. Absolute change from baseline in EREFS total score (0−18), and EREFS inflammation (0−10) and remodelling (0−8) subscores were assessed at Weeks 16 and 52. Results A total of 37 and 34 patients received dupilumab HE and placebo, respectively; baseline mean EREFS scores were similar across treatment groups (6.8 vs 7.3) with EREFS inflammation subscores higher than remodelling subscores (6.0 vs 0.9 in the total population). EREFS total score was significantly reduced at Week 16 with dupilumab HE versus placebo (LS mean difference -3.8 [95% CI: -4.9, -2.6], P<0.0001), with improvement sustained through Week 52 in the dupilumab HE group (figure). Similar improvements were observed for EREFS inflammation subscore. Assessment of changes in remodelling was limited by low prevalence of fibrostenotic features in young children. Conclusion Dupilumab HE led to significant improvement in EREFS total score at Week 16 versus placebo, which was sustained through Week 52. Dupilumab HE also improved EREFS inflammation subscore.