Poster Session II - A191 REAL-WORLD OUTCOMES OF DUPILUMAB FOR TREATMENT OF EOSINOPHILIC ESOPHAGITIS

Abstract Background Eosinophilic esophagitis (EoE) is a chronic, immune-mediated inflammatory disease characterized by eosinophil-predominant inflammation causing esophageal dysfunction. Dupilumab, an anti–IL-4/13 monoclonal antibody, is the first biologic approved for EoE. Since Health Canada approval in 2023, real-world data remain limited. Aims To evaluate clinical, endoscopic, and histologic outcomes in EoE patients treated with dupilumab. Methods A multicenter retrospective review was conducted at four tertiary hospitals in Montreal and Vancouver. Included are biopsy-proven EoE adult and pediatric patients with ≥1 follow-up endoscopy ≥12 weeks after starting dupilumab. Primary outcomes are changes in Eosinophilic Esophagitis Endoscopic Reference Score (EREFS), Index of Severity for Eosinophilic Esophagitis (I-SEE), and peak eosinophil count per high-power field (eos/HPF) on pathology. Secondary outcomes include symptom improvement and post-treatment dilation. Results Of the 49 patients on dupilumab, 36 met inclusion criteria (5 pediatric, 31 adult). Mean pre-treatment EREFS was 2.9±1.9, with a mean 70.1±31.4 eos/HPF on histology. After a mean treatment duration of 44.7±25.7 weeks, EREFS and eos/HPF improved to 1.1±1.1 and 4.5±9.0, respectively. We observed improvements in EREFS, I-SEE score, and eos/HPF post-dupilumab treatment (p < 0.001, Fig. 1). Subjective clinical improvement occurred in 97.2% of patients. During treatment, 37.1% and 90.1% discontinued PPI and inhaled steroids, respectively. Three patients stopped dupilumab for lack of efficacy, pregnancy, and initiation of a new biologic for vasculitis. Four patients had mild injection site reactions, and only three required post-treatment esophageal dilations. Conclusions Our real-world data show dupilumab is a safe, highly effective therapy for EoE across pediatric and adult populations, improving endoscopic, clinical, and histologic disease activity. Funding Agencies None