Omalizumab as Monotherapy and as Adjunct Therapy to Multi-Allergen OIT in Food Allergic Participants

This study is a multi-center, randomized, double-blind, placebo-controlled study in participants 1 to less than 56 years of age who are allergic to peanut and at least two other foods (including milk, egg, wheat, cashew, hazelnut, or walnut). While each participant may be allergic to more than two other foods, the primary endpoint/outcome in this study will only be assessed in peanut and two other foods for each participant. The primary objective of the study is to compare the ability to consume foods without dose-limiting symptoms during a double-blind placebo-controlled food challenge (DBPCFC), after treatment with either omalizumab or placebo for omalizumab.

Food allergy affects about 15 million people in the United States. This includes 6 million children. The current treatment for food allergy is to avoid eating the foods that may cause an allergic reaction and have medications such as epinephrine (adrenaline) in case of a reaction. However, accidental exposures can be extremely difficult to avoid, particularly if you are allergic to multiple foods. The risks of accidental exposures and life-threatening reactions can place a large burden on patients and their families. Investigators in this study would like to learn if omalizumab injections alone or in combination with multi-allergen oral immunotherapy (OIT) will help people with multiple food allergies eat foods to which they are allergic. Oral means that you will take the food allergen (peanut and 2 other foods to which you are allergic) by mouth. If you are allergic to more than 3 foods, this study will only provide OIT for peanut and 2 other foods. There are 3 stages to the study: In Stage 1, investigators would like to learn: • If omalizumab stops or decreases allergic reactions to peanut and other common food allergens after taking it for a length of time. Stage 1 will also have an extra part so that 60 participants will receive omalizumab and everyone (the investigators conducting the research and study participants) will know it. This is why it is called the open label extension. This part of the study will assist investigators in learning if receiving omalizumab for a longer time may work better at decreasing allergic reactions. In Stage 2, investigators would like to learn: • How a short course of omalizumab combined with Multi-allergen OIT compares with a longer course of omalizumab in decreasing allergic reactions. In Stage 3, investigators would like to learn: • If, after participants stop both treatments, will they be able to eat the peanut and the 2 other foods in the form that is normally eaten. In all stages, investigators would like to learn: * How safe and effective the treatments are and * How the OIT affects the immune system. Participation will last up to 56 months (4 years and 8 months).