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

• Omalizumab (Drug): Prior to starting omalizumab, participants will undergo a baseline oral food challenge. Participants will then initiate omalizumab treatment as prescribed by their doctor as part of routine clinical care. After 2 to 4 weeks of treatment (following one to two doses of omalizumab), participants will undergo a first post-treatment oral food challenge to assess treatment response. After 4 to 6 months of omalizumab treatment, participants will undergo a second post-treatment oral food challenge. The study will conclude following the second post-treatment oral food challenge.

Primary outcomes

• Proportion of participants achieving pre-specified thresholds without dose-limiting symptoms during first post-treatment oral food challenge. [Between ≥14 and ≤35 days after starting omalizumab]: The pre-specified thresholds for response is defined as the ability to consume at least two more incremental doses of food protein during post-treatment oral food challenge (using incremental doses of 3, 10, 30, 100, 300, 600, 1000, 2000, 2000, and 2000 mg), than during the baseline oral food challenge. First post-treatment oral food challenge conducted between ≥14 and ≤35 days after starting omalizumab (after one or two doses of omalizumab depending on whether the participant is receiving omalizumab every 2 or 4 weeks).

Secondary outcomes

• The absolute change in oral food challenge threshold between baseline and the first post-treatment oral food challenge. [Baseline, between ≥14 and ≤35 days after starting omalizumab]: Baseline oral food challenge conducted prior to starting omalizumab. First post-treatment oral food challenge conducted at ≥14 and ≤35 days after starting of omalizumab.
• The absolute change in oral food challenge threshold between the first and second post-treatment oral food challenges. [between ≥14 and ≤35 days after starting omalizumab, 4-6 months after starting omalizumab]: First post-treatment oral food challenge conducted at ≥14 and ≤35 days after starting of omalizumab. Second post-treatment oral food challenge conducted between 4 to 6 months after starting omalizumab.

Other outcomes

• Correlation between oral food challenge threshold and biomarkers including skin prick testing, allergen-specific IgE, total IgE, and free total IgE. [At baseline, between ≥14 and ≤35 days starting omalizumab, and 4 to 6 months after starting omalizumab]: Oral food challenge threshold measures the amount of food protein (mg) consumed without dose-limiting symptoms. Biomarkers include skin prick test measured by wheal diameter (mm), allergen-specific IgE concentration (kUA/L), total IgE concentration (IU/mL), and free total IgE concentration (IU/mL).

Sex: All, ages: 1 Year to 30 Years

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.

• Robert Wood, MD, Principal investigator, Johns Hopkins University