The efficacy and safety of dupilumab therapy in pediatric patients with refractory eosinophilic duodenal bulb ulcer: a retrospective cohort study

Background Refractory eosinophilic duodenal bulb ulcer (REDU) is a rare and poorly characterized subtype of non–eosinophilic esophagitis eosinophilic gastrointestinal disease (non-EoE EGID). Standard therapies are often ineffective, and evidence for biologic treatment is limited. Objective This study aims to evaluate the efficacy and safety of dupilumab in pediatric patients with REDU. Methods This retrospective cohort study included 13 pediatric patients with histologically confirmed REDU treated with dupilumab for 12 weeks between January and December 2025, followed by a 24-week extension period. Primary outcomes were endoscopic healing and histological remission. Secondary outcomes included symptom improvement, laboratory parameters, growth indices, and quality of life (EGGE-QOL). An exploratory cross-sectional transcriptomic analysis compared pretreatment REDU biopsies with healthy-control biopsies. Results All patients achieved marked clinical improvement after 12 weeks of treatment. The median duodenal eosinophil count decreased significantly from 95 (IQR 72.5–100.0) to 3.5 (1.5–10.0) cells/HPF (P < 0.001), with histological remission achieved in all cases. Peripheral eosinophil counts and hemoglobin levels were improved significantly (both P < 0.05). Endoscopic mucosal healing was observed in all patients, with 11 achieving scar-stage healing. EGGE-QOL scores improved significantly (61.85 ± 16.90 vs 32.31 ± 18.85, P < 0.001). Exploratory RNA sequencing of pretreatment REDU biopsies versus healthy-control biopsies identified 837 genes meeting the nominal screening criteria, including 472 with higher and 365 with lower expression in pretreatment REDU biopsies. The top-ranked functional annotations were related to immune responses and cytokine signaling. Conclusions Dupilumab demonstrated promising efficacy and acceptable safety in pediatric REDU, with consistent clinical, histological, and molecular improvements. These findings support further prospective studies to validate its long-term efficacy in non-EoE EGIDs.