Peanut Reactivity Reduced by Oral Tolerance in an Anti-IgE Clinical Trial

36 subjects will receive Xolair, and 8 subjects will receive placebo. The study will occur at
4 sites: Boston Children's Hospital, Children's Hospital of Philadelphia, Stanford University
and Lurie Children's Hospital.

Patients will be pre-treated with Xolair or placebo before rapid oral peanut desensitization.
Patients will continue to receive Xolair during the 8 subsequent weeks of desensitization,
receiving their final dose of Xolair one week after reaching the highest tolerated dose of
peanut.

Inclusion Criteria:

- Moderate to severe peanut allergy-sensitive subjects between the ages of 7 to 25 years
old.

- Sensitivity to peanut allergen will be documented by a positive skin prick test result
(6 mm diameter wheal or greater)

- ImmunoCAP IgE level to peanut > 10 kU/L.

- Sensitivity to peanut allergen based on a double-blind placebo-controlled oral food
challenge (DBPCFC) at maximum of cumulative 175 mg of peanut protein dose.

Exclusion Criteria:

- Subjects with a total IgE at screening of < 50 kU/L > 2,000 kU/L.

- Positive reaction to the placebo on DBPCFC.

- Previous reaction to omalizumab.

- Subjects having a history of severe anaphylaxis to peanut requiring intubation or
admission to an ICU, frequent allergic or non-allergic urticaria, or history
consistent with poorly controlled persistent asthma, or gastrointestinal or
gastroesophageal disease.