This trial will study three doses of reslizumab versus placebo in children with Eosinophilic Esophagitis (EE). The objectives of the trial will be to study the effectiveness of reslizumab in improving the clinical signs and symptoms and reducing esophageal eosinophils as well as assessing the safety profile compared to placebo.

Inclusion Criteria:

• written informed consent obtained
• male or female patients aged 5 to 18 years at time of screening
• of non-childbearing potential, of childbearing potential and willing to use specific barrier methods outlined in the protocol
• confirmed active eosinophilic esophagitis (at Screening or within six weeks prior to Baseline Visit) as defined by esophageal mucosal eosinophils greater than or equal to 24 per hpf (400X magnification)
• within the week prior to dosing, patient has one of the following symptoms of moderate (or worse) severity: vomiting, regurgitation (acid taste or feeling material movement upward, abdominal, chest pain/heartburn (burning or pain behind the sternum), or difficulty swallowing
• been on a therapeutic dose of PPIs (with or without histamine H2 receptor antagonists)for at least four weeks without resolution of symptoms, or by negative pH probe (with or without having failed a course of PPIs)

Exclusion Criteria:

• another disorder that causes esophageal eosinophilia (e.g.,HES,Churg Strauss vasculitis, EG, or a parasitic infection)
• history of abnormal gastric or duodenal biopsy or documented GI disorders (e.g.,Celiac Disease, Crohn's disease or Helicobacter pylori infection)
• history of the following GI surgeries:fundoplication, gastric surgery or surgery for intestinal atresia -use of systemic immunosuppressive or immunomodulating agents (anti- immunoglobulin E [IgE] mAb, methotrexate, cyclosporin, interferon α, or anti tumor necrosis factor [TNF] mAb) within six months prior to study entry.
• received attenuated live attenuated vaccines (e.g., measles, mumps, rubella [MMR], Bacille Calmette Guerin [BCG],varicella, Flumist or polio) within three months prior to study entry.
• use of swallowed inhaled corticosteroids for the treatment of EE within two months prior to study entry. Note: Inhaled and nasal corticosteroids for the treatment of asthma and allergies, respectively, are permitted provided that the dose remains the same during the study
• a stricture on endoscopy that prevents passage of the endoscope
• participation in any investigational drug or device study within 30 days prior to study entry.
• female subjects who are pregnant or nursing.
• concurrent infection or disease that may preclude assessment of eosinophilic esophagitis.
• concurrent immunodeficiency (human immunodeficiency [HIV], or acquired immunodeficiency syndrome [AIDS] or congenital immunodeficiency).