The 2024 AAAAI meeting did not disappoint. As one of the largest academic allergy societies in the world, I have high expectations for this meeting every year. As a food allergist, I expect presentations on cutting-edge science; that’s just what I saw.

Full disclosure: I almost didn’t attend. As a mom to two young children and married to another clinician (who’s not an allergist), traveling takes effort. But I was receiving an award, so I wanted to attend in person and express gratitude to my colleagues and mentors.

What I didn’t know when we planned our trip to Washington, D.C., was that the FDA would approve — the week before the conference — the first drug ever to prevent anaphylactic reactions to any food. The name of that drug? Omalizumab. The study? OUtMATCH.

Omalizumab Prevents Anaphylactic Reactions

To understand how omalizumab prevents anaphylaxis, you must know that anaphylaxis occurs when mast cells degranulate. In the case of Immunoglobulin E (IgE)-mediated peanut allergy, when a patient ingests peanut, peanut protein binds to peanut-specific IgE on mast cells, triggering mast cell degradation, which then causes the signs and symptoms of anaphylaxis. In most cases of IgE-mediated food allergy, the allergen is a protein, and allergic reactions occur within minutes to a couple of hours. The exception is Alpha-Gal Syndrome, in which the allergen is a carbohydrate, and the reaction occurs hours after ingestion.

It’s important to note that not all patients with food-specific IgE have a food allergy. Having a positive IgE test indicates a person is “sensitized,” but having a positive test and a clinical history of allergic reaction when that food is ingested suggests IgE-mediated food allergy. Why some patients are sensitized but not allergic is due to immune tolerance, which is created through poorly-understood mechanisms involving regulatory T-cells.

It’s also important to note that not all food allergy conditions are IgE-mediated, meaning not all are potentially anaphylactic. Examples of non-IgE-mediated food allergies include eosinophilic esophagitis and food protein-induced enterocolitis syndrome, both of which can cause significant morbidity.

Omalizumab prevents anaphylactic reactions to foods by interfering with IgE-mediated mast cell degranulation. Omalizumab itself is an antibody. It binds to IgE, thus preventing IgE from binding to mast cells (amongst other pro-allergy mechanisms impacted), thereby diminishing allergic reactions. 

Omalizumab is not a new medication. It’s been used to manage asthma for two decades. It’s also used to manage hives. While it is an injection and, like all medications, carries risks, omalizumab is a relatively safe drug.

What Other Therapies Are Available for Ige-Mediated Food Allergies?

The most commonly available therapy is oral immunotherapy (OIT). OIT is the process by which tiny amounts of the allergen are ingested daily by the patient. Doses are increased every few weeks until the patient reaches a maintenance dose. For example, my peanut-allergic patients may start OIT by ingesting a few milligrams of peanut protein every day, and we increase that dose every two weeks until they reach half a teaspoon of peanut butter (~600mg peanut protein). Patients on OIT typically have one of two goals: become “bite-proof,” meaning a small, accidental ingestion will not trigger a severe reaction, or “free-eat,” meaning the patient is able to incorporate the food into the diet. In all cases, the food must continue to be ingested in some capacity, or there’s risk of tolerance waning, hence this not being a “cure.” 

OIT has been used to treat IgE-mediated food allergies for nearly twenty years. Peanut Allergen Powder-dnfp is an FDA-approved medication used for peanut OIT. Unlike omalizumab, Peanut Allergen Powder-dnfp is not a biologic medication — it is peanut flour stored in dose-specific capsules. The significant down-side of OIT when using whole foods or Peanut Allergen Powder-dnfp is the risk of allergic reaction and, to mitigate that risk, the three-hour safety window that patients must follow, prohibiting activities that raise the body temperature or heart rate for one hour before to two hours after dosing. This, along with the multi-appointment nature of OIT, limits who participates in OIT.

Another treatment option is sublingual immunotherapy (SLIT). SLIT involves placing microgram to milligram amounts of allergen under the tongue via drops. SLIT carries a more relaxed safety window because it’s tolerated better than OIT; however, SLIT has not been shown to be as powerful as OIT at inducing tolerance. That said, SLIT very often can lead to a patient becoming “bite-proof,” which, in addition to helping to keep the patient safe from accidental ingestions, can dramatically improve the entire family’s quality of life.

Other treatments for food allergies, such as epicutaneous immunotherapy, are currently being researched and are promising.

Aside from immunotherapy, patients can continue the practice of actively avoiding their allergen. Depending on a patient’s age and allergen(s), some food allergies will self-resolve.

Is Omalizumab safe?

All medications have risks, but given how long omalizumab has been used in treating allergic conditions, patients and prescribers can feel reassured that this is not a brand-new medication. We, as allergists, aren't expecting surprises to omalizumab's safety profile, but allergists prescribing omalizumab should, of course, be monitoring for adverse effects.

Omalizumab is promising, and there’s more to come

After decades of patients and their families suffering from food allergies and the inevitable thoughts of “what if my child accidentally eats the allergen? Will my child be one of those rare but real cases of dying from a peanut?” It was exciting to sit in a packed auditorium and hear esteemed allergist Dr. Robert Wood discuss the strong data of the OUtMATCH study. It’s reassuring that a medication that has been around for years can help our patients, whether they have one or many IgE-mediated food allergies. 

Is omalizumab perfect for everyone? No. There are two elephants in the room. First, it’s a shot administered at least monthly, and second, the treatment duration is indefinite. However, can omalizumab help keep our patients safe and help families feel safer? A resounding yes, and that’s progress for which I’m grateful.

Dr. Hoyt has no conflicts of interest to report.

Illustration by Jennifer Bogartz