Oral Food Challenge After One to Two Doses of Omalizumab Treatment for Food Allergy

Inclusion Criteria:

* Age 1 to 30 years.
* Patients with diagnosed food allergy to at least one of the following foods (milk, egg, wheat, peanut, cashew, or walnut) who were prescribed omalizumab for food allergy in the clinical setting at the Johns Hopkins pediatric or adult allergy clinic.
* Positive food-specific IgE (≥2.0 kUA/L) to the relevant food OR a positive skin-prick test with a wheal ≥4 mm larger than the saline control.
* Positive open oral food challenge at baseline screening evaluation to the relevant food with dose-limiting symptoms at a single dose of ≤1000 mg (cumulative dose of ≤2043 mg) prior to starting omalizumab (using incremental doses of 3, 10, 30, 100, 300, 600, 1000 mg).
* Prior authorization from the patient's insurance provider for clinical use of omalizumab.

Exclusion Criteria:

* Clinically significant laboratory abnormalities in the past 6 months.
* Sensitivity or suspected/known allergy to any ingredients (including excipients) of omalizumab
* Poorly controlled or severe asthma/wheezing at screening
* History of severe anaphylaxis to the participant-specific food that will be used in this study, defined as neurological compromise or requiring intubation.
* Currently receiving oral, intramuscular (IM), or intravenous (IV) corticosteroids, tricyclic antidepressants, or β-blockers.
* Past or current history of cancer, or currently being investigated for possible cancer.
* Past or current history of any food immunotherapy, such as oral immunotherapy (OIT), sublingual immunotherapy (SLIT), epicutaneous immunotherapy (EPIT) within 6 months of screening.
* Treatment with monoclonal antibody therapy, such as omalizumab, dupilumab, benralizumab, mepolizumab, reslizumab, tezepelumab, or other immunomodulatory therapy within 6 months of screening.
* Inability to discontinue antihistamines for minimum wash-out periods required for skin-prick test or oral food challenge.
* Pregnant or breastfeeding, or intending to become pregnant during the study
* Evidence of clinically significant chronic disease.