Xolair From Genentech

The FDA has approved omalizumab injection (Xolair) from Genentech to reduce type 1 allergic reactions, including anaphylaxis, due to accidental exposure to food allergens in adults and pediatric patients 1 year and older with immunoglobulin E (IgE)–mediated food allergy. Omalizumab should be used in conjunction with food allergen avoidance. The approval carries the limitation that omalizumab is not indicated for the emergency treatment of allergic reactions, including anaphylaxis.¹

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In the United States, IgE-mediated food allergies affect approximately 3.4 million children and 13.6 million adults, and more than 40% of children and 50% of adults with food allergies have experienced at least 1 severe reaction. Food-related anaphylaxis accounts for an estimated 30,000 emergency department medical events each year.²

PHARMACOLOGY AND PHARMACOKINETICS

Omalizumab inhibits the binding of IgE to the high-affinity IgE receptor on the surface of basophils, dendritic cells, and mast cells, resulting in downregulation. It reaches peak serum concentrations after 7 to 8 days of treatment and has an average elimination half-life of 26 days.¹

DOSAGE AND ADMINISTRATION

The recommended dose of omalizumab for IgE-mediated food allergy is 75 mg to 600 mg subcutaneously every 2 or 4 weeks. Refer to the prescribing information for patientspecific dose and frequency based on pretreatment serum total IgE level and body weight.¹

CLINICAL TRIALS

Omalizumab was evaluated for efficacy and safety in a double-blind, multicenter, placebo-controlled, randomized trial (phase 3 OUtMATCH; NCT03881696) of patients with allergies to peanut and at least 2 other foods, including cashew, egg, hazelnut, milk, walnut, and wheat. Patients were randomly assigned 2:1 to receive omalizumab subcutaneously or placebo based on baseline serum total IgE level and body weight for 16 to 20 weeks, and then completed a double-blind placebo-controlled food challenge of placebo and each of their 3 studied foods.

The study met its primary efficacy end point, which was the percentage of patients who were able to consume a single dose of greater than or equal to 600 mg of peanut protein without dose-limiting symptoms. The study demonstrated that 68% of the patients who received omalizumab tolerated the allergen vs 5% in the placebo group. The study also met its secondary efficacy end points. In the omalizumab group, 42% tolerated at least 1000 mg of cashew vs 3% in the placebo group, 67% tolerated at least 1000 mg of egg protein vs 0% in the placebo group, and 66% tolerated at least 1000 mg of milk vs 11% in placebo group.^1,2

CONTRAINDICATIONS, WARNINGS, AND PRECAUTIONS

Omalizumab carries a boxed warning stating that anaphylaxis has been reported after administration. Treatment with omalizumab should be initiated in a health care setting that is prepared to manage potentially life-threatening anaphylaxis, and patients should be closely observed for an appropriate period of time after administration of the dose. Patients should be educated about the signs and symptoms of anaphylaxis and instructed to seek immediate medical care if symptoms occur. Treatment with omalizumab is contraindicated in patients with a history of hypersensitivity to the medication or any of its components.

Malignancies have been observed in clinical trials of patients using omalizumab. Omalizumab should be discontinued if patients develop signs or symptoms similar to serum sickness, such as arthritis, arthralgia, fever, lymphadenopathy, and rash. After administration of omalizumab, serum total IgE levels increase due to the formation of omalizumab-IgE complexes, and these elevations may continue for up to 1 year after discontinuation. Serum total IgE levels obtained less than 1 year after discontinuation should not be used to determine dosing regimens. Omalizumab should not be used for the emergency treatment of allergic reactions, including anaphylaxis. Patients should be educated that omalizumab is a maintenance medication to reduce allergic reactions, while still avoiding food allergens.

When used for IgE-mediated food allergy, the most common adverse reactions are injection site reactions and pyrexia.¹

References

1. Xolair. Prescribing information. Genentech; 2024. Accessed February 29, 2024. https://www.gene.com/download/pdf/xolair_prescribing.pdf

2. FDA approves Xolair as first and only medicine for children and adults with one or more food allergies. Press release. Genentech; February 16, 2024. Accessed February 29, 2024. https://www.gene.com/media/press-releases/15019/2024-02-16/fda-approves-xolair-as-first-and-onlyme#:~:text=Genentech%2C%20a%20member%20of%20the,foods%20in%20adult%20and%20pediatric