Clinical Study Using Biologics to Improve Multi OIT Outcomes (COMBINE)

Inclusion Criteria: * Age 4 through 55 years (inclusive). * Clinical history of peanut allergy and 1 or 2 additional foods from the following foods: milk, almond, shellfish, fish, cashew, hazelnut, egg, walnut, sesame seeds, soy, and wheat. Allergy to milk and egg is defined as unable to tolerate both cooked and uncooked forms. * Positive allergy test determined by: * ImmunoCAP serum IgE level \>4 kUA/L for each allergen within the past 12 months OR * Skin prick test (SPT) ≥6 mm wheal diameter to each allergen. * A clinical reaction during a DBPCFC to small doses of food defined as a cumulative dose of =/\<444 mg food protein. * No clinical reaction observed during the placebo (oat) challenge. * Subject and/or parent guardian must be able to understand and provide informed consent. * Written informed consent from adult participants. * Written informed consent from parent/guardian for minor participants. * Written assent from minor participants as appropriate (e.g., at and above the age of 7 years). * Use of effective birth control by female participants of childbearing potential. Exclusion Criteria: * History of cardiovascular disease, including uncontrolled or inadequately controlled hypertension. * Individuals less than 15 kg in weight at start of the study * History of severe anaphylaxis to participant-specific foods that will be used in this study, defined as neurological compromise or requiring intubation. * History of chronic disease (other than asthma, atopic dermatitis or allergic rhinitis) that is, or is at significant risk of becoming, unstable or requiring a change in chronic therapeutic regimen. * History of eosinophilic esophagitis (EoE), another eosinophilic gastrointestinal disease, chronic, recurrent, or severe gastroesophageal reflux disease (GERD), symptoms of dysphagia (e.g., difficulty swallowing, food "getting stuck"), or recurrent gastrointestinal symptoms of undiagnosed etiology. * Severe asthma (NAEPP EPR-3 Medication Criteria Steps 5 or 6) * Mild or moderate asthma (NAEPP EPR-3 Medication Criteria Steps 1-4), if uncontrolled or difficult to control. * Uncontrolled asthma as evidenced by: * FEV1 \< 80% of predicted, or ratio of FEV1 to forced vital capacity (FEV1/FVC) \< 75% of predicted, with or without controller medications (only for age 6 or greater and able to do spirometry reliably. If unable to do spirometry, PEF of \>80% is acceptable) or; * One overnight admission to a hospital in the past year for asthma or; * Emergency room (ER) visit for asthma within six months prior to screening. * Inability to tolerate biological (antibody) therapies. * Use of immunomodulator therapy (not including corticosteroids). * Use of beta-blockers (oral), angiotensin-converting enzyme (ACE) inhibitors, angiotensin-receptor blockers (ARB) or calcium channel blockers. * Current participation or within the last 4 months in any other interventional study. * Pregnancy or lactation. * Allergy to oat (placebo in DBPCFC). * Use of investigational drugs within 16 weeks of participation. * In build up phase of immunotherapy for aeroallergens or venom.