Pediatric Regeneron Dupilumab R668-EE-1877 Study

Key Inclusion Criteria:

1. A documented diagnosis of eosinophilic esophagitis (EoE)
2. Baseline endoscopic biopsies with a demonstration on central reading of intraepithelial eosinophilic infiltration

Key Exclusion Criteria:

1. Body weight <5 kg or ≥60 kg at screening
2. Other causes of esophageal eosinophilia
3. Active Helicobacter pylori
4. History of Crohn's disease, ulcerative colitis, celiac disease, or prior esophageal surgery
5. Any esophageal stricture unable to be passed with a standard, diagnostic, upper endoscope or any critical esophageal stricture that requires dilation at screening
6. Treatment with swallowed topical corticosteroids within 8 weeks prior to baseline standard of care endoscopy
7. History of bleeding disorders or esophageal varices that, in the opinion of the investigator, would put the patient at undue risk for significant complications from an endoscopy procedure
8. Active parasitic infection or suspected parasitic infection
9. Known or suspected immunodeficiency disorder

Key Exclusion for Patients Re-Entering the Study (for Entry into Part C, as defined in protocol):

1. Patients who are ≥12 years old, weigh ≥40 kg (or minimum weight for which dupilumab is approved for EoE), and dupilumab is commercially available for the treatment of EoE in their country
2. Patients who, during their previous participation in this clinical trial, developed an SAE and/or AE deemed related to dupilumab, which in the opinion of the investigator or of the medical monitor could indicate that continued treatment with dupilumab may present an unreasonable risk for the patient
3. Patients who did not undergo endoscopy with biopsies at week 16 and/or week 52 or prior to receiving rescue treatment Note: If the endoscopy with biopsies could not occur due to COVID-19 restrictions and rescue treatment was needed to be initiated without delay, these patients will be eligible to participate in Part C
4. Patients who became pregnant during their previous participation in this dupilumab clinical trial
5. Patients who, during their previous participation in this trial, were prematurely withdrawn because of a protocol violation, poor compliance, or inability to complete required study assessments

NOTE: Other protocol defined inclusion/exclusion criteria apply