This study is designed to investigate the effects of a 12 week course of intravenous QAX576 6mg/kg every 4 weeks in reducing the number of eosinophils in the esophagus of EoE patients by 75% or greater when compared with baseline.

Inclusion Criteria:

• Males and females aged 18-50 with symptomatic eosinophilic esophagitis
• Female subjects must be women of non child bearing potential.
• Elimination diet must have been tried.
• Treatment for at least two months prior to enrollment on a protocol pump inhibitor .
• Appropriate contraception must be used by males, (e.g., spermicidal gel plus condom)
• Must be able to communicate well with the investigator, to understand and comply with the requirements of the study.
• Understand and sign the written informed consent.

Exclusion criteria:

• Have received corticosteroids within 3 months before starting the study for any symptoms.
• Any other eosinophilic disorders.
• History of clinical schistosomiasis, or having travelled within the preceding 6 months to an area with endemic schistosomiasis, including but not limited to Southeast and Southwest Asia, South America and Africa. Travel to these areas must not be planned for at least 6 months after the last dose.
• Donation or loss of 400 ml or more of blood within eight (8) weeks prior to initial dosing.
• History of immunodeficiency diseases, including a positive HIV (ELISA and Western blot) test result.
• History of drug or alcohol abuse within the 12 months prior to dosing, or evidence of such abuse as indicated by the laboratory assays conducted during the screening.

Other protocol-defined inclusion/exclusion criteria may apply