A study to investigate changes of symptoms and esophageal cell structure with tezepelumab compared with placebo in patients aged 12 to 80 years old with eosinophilic esophagitis. Subjects up to 21 years of age will be enrolled at CHOP.

The main objective of this study is to see if repeat subcutaneous doses of dupilumab, the study medicine, helps to reduce eosinophilic inflammation in the stomach of participants with eosinophilic gastritis/ eosinophilic gastroenteritis compared to a placebo. A placebo is a pill or substance that is given to a patient like a drug but that has no physical effect on the patient.

The goal of this study is to evaluate the effectiveness of a new blood test for Eosinophilic Esophagitis (EoE). Eligible participants include patients undergoing their first upper endoscopy for evaluation of EoE, or who have already been diagnosed with EoE, but whose food sensitivities are currently unknown. The findings of this study will contribute to the development of clinical diagnostic tools (ie. blood tests for food allergies) that will decrease the time needed to identify food sensitivities, and subsequently reduce the time to symptom resolution for newly diagnosed patients with EoE.