Anti-Interleukin-5 (IL-5) Study for Hypereosinophilic Syndrome

The purpose of the study is to assess the toxicity of anti-IL-5, and to see whether it
lowers peripheral blood eosinophils and/or tissue and whether it has a steroid and/or
interferon sparing effect.

Inclusion Criteria:

- Adequate renal, cardiac, and hepatic function

- Not pregnant or breastfeeding

- A diagnosis of hypereosinophilic syndrome such as:

- Idiopathic hypereosinophilic syndrome;

- Eosinophilia myalgia syndrome;

- Eosinophilic gastroenteritis;

- Churg-Strauss syndrome;

- Eosinophilic cellulitis;

- Benign hypereosinophilia; or

- Eosinophilic esophagitis.

- Maintained on, or in need of, the following: glucocorticoids, interferon,
methotrexate, hydroxyurea, cytoxan, 6-mercaptopurine, or vincristine

- Blood eosinophil counts greater than 750 cells/mcl

Exclusion Criteria:

- Creatinine > 3 X upper limit for age

- AST > 5 X upper limit for age

- Platelet count < 50,000/mm3

- Cardiac function:

1. NYHA class IIIb or IV (patients with shortness of breath or fatigue with mild
exertion or at rest);

2. Patients with symptomatic supraventricular or ventricular arrythmias requiring
treatment;

3. Patients requiring IV heart failure medications;

4. Angina or acute myocardial infarction

- History of renal, hepatic, endocrine, oncologic, cardiovascular disease, or any other
condition which, in the opinion of the Investigator, would jeopardize the safety of
the patient or impact on the validity of the study results

- History of allergic or adverse response to previous antibody type therapy

- History of allergic or adverse response to anti-IL-5 therapy

- Evidence of, or history of, a parasitic infection (within past 1 year)

- Participation in a previous clinical trial involving an investigational agent within
30 days prior to study initiation

- Receipt of anti-IL-5 therapy in the past

- Blood donation of 450 ml (1 pint) or more within 30 days prior to study initiation

- Abnormal or unusual diet or substantial changes in eating habits within 30 days prior
to, or during, the study.

- Patients who do not have eosinophil levels > 750 cells/mcl after the run-in period.
Patients who have only eosinophilic infiltration of tissue are eligible if they do
not develop an eosinophil level > 750 cells/mcl, assuming that they meet all other
eligibility requirements.

- Positive serum pregnancy test

- Breastfeeding

- Unable to use effective birth control methods for duration of study

- Unable or unwilling to give voluntary informed consent/assent