Proof of Concept Study of OC000459 in Eosinophilic Esophagitis

Inclusion Criteria: * Previously diagnosed and symptomatic isolated eosinophilic esophagitis. * Relevant eosinophil tissue inflammation as demonstrated by a mean eosinophil load \>= 20 eos/hpf in 8 biopsies at the baseline visit. * Able to swallow placebo medication successfully under supervision in the clinic * Free of all medications for EoE (including topical steroids) for at least 2 weeks prior to baseline and free of systemic steroids for at least 90 days before screening. A proton-pump inhibitor is allowed if required for treatment of secondary acid reflux. Exclusion Criteria: * Other causes of esophagitis (GERD, peptic ulceration, infection etc.) * Other causes of eosphagaeal or generalized eosinophilia (i.e. hypereosinophilic syndromes, parasitic infection, GERD) * The patient's EoE is dependant on the level of seasonal allergens and the patient's participation in the study will occur during the allergy season. * History of abnormal gastric or duodenal eosinophilia (e.g. HES, Churg Strauss vasculitis, EG or a parasitic infection) * Receipt of forbidden prescribed or over the counter medication within the 4 weeks prior to the baseline visit and for the duration of the trial, including vitamins and herbal remedies.