**17.1 IL-4 inhibitor**

Dupilumab is an interleukin-4 receptor antagonist/monoclonal antibody. It has been found to be effective in improving dysphagia and esophageal eosinophilia (intraepithelial eosinophil count of ≤6 eosinophils per high-power field) in a double blind, placebo-controlled, pivotal phase 3 trial (Part A) that evaluated its efficacy in 81 patients aged ≥12 years with EoE. Dupilumab was granted Breakthrough Therapy designation by the FDA (Food and Drug Administration, USA) in September, 2020 for the treatment of the patients aged ≥12 years with EoE [50]. This designation would allow expedited review of dupilumab for the FDA approval.
