From the Center for Esophageal Diseases and Swallowing, University of North Carolina School of Medicine, Chapel Hill (E.S.D.); Cincinnati Children's Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati (M.E.R., M.H.C.); Northwestern University Feinberg School of Medicine, Chicago (I.H.); Mount Sinai Center for Eosinophilic Disorders, Icahn School of Medicine at Mount Sinai, New York (M.C.), and Regeneron Pharmaceuticals, Tarrytown (X.S., M.P.K., M.A.K., J.D.H., B.B., E.M., B.A., N.A., W.K.L., M.F.W., M.R., D.R.W., G.D.Y., B.S., J.M., A.G., A.S.) - both in New York; Amsterdam University Medical Center, Amsterdam (A.J.B.); Hospital General de Tomelloso, Centro de Investigación Biomédica en Red en Enfermedades Hepáticas y Digestivas, Madrid, and Instituto de Investigación Sanitaria de Castilla-La Mancha, Toledo - both in Spain (A.J.L.); Children's Hospital of Philadelphia, Philadelphia (J.M.S.); University of California, San Diego, La Jolla, and Rady Children's Hospital, San Diego - both in California (S.A.); Sanofi, Bridgewater, NJ (K.P., E.L.); Sanofi, Chilly-Mazarin, France (L.P.M.); and Sanofi, Cambridge, MA (N.P.).