Oral immunotherapy (OIT) is an emerging food allergy treatment. It is meant to desensitize a child to the food they are already allergic to --- in other words, to make them “less allergic” to a food. But since it requires a child to be exposed to their allergen, it is not without risks.
Today, we’ll cover everything food allergy families need to know about OIT.
What is oral immunotherapy?
What is oral immunotherapy? How and why can it help a child with existing food allergies?
Oral immunotherapy (OIT) is an emerging type of food allergy treatment. It is meant to desensitize a child to the food they are already allergic to --- in other words, to make them “less allergic” to a food.
When successful, OIT will help protect a child with an existing food allergy from developing a severe allergic reaction, in case they accidentally eat a small amount of the food they are allergic to.
In oral immunotherapy, a child consumes small, controlled doses of the food that the child is allergic to. These doses are slowly increased over time until a certain target dose is reached.
This gradually increasing exposure is meant to increase someone’s “reaction threshold,” or increase the amount of the allergen they can consume without experiencing an allergic reaction.
OIT treatment is closely supervised by an allergist, clinical researchers, or both.
Is oral immunotherapy a food allergy “cure?”
Oral immunotherapy is not a “cure” for food allergies.
It is only designed to desensitize someone to an allergen, or protect them from a severe reaction in case they accidentally eat smaller amounts of their allergen.
The person may experience a less severe reaction, or no reaction at all, when they eat those smaller amounts.
But they still can’t intentionally eat a meal that contains their allergen. Young people undergoing OIT must still strictly avoid their allergen(s) in their everyday diet.
This protection from small amounts or exposure also only lasts while the child is receiving continued OIT treatment.
This is very different from tolerance (see the image below), where someone can eat any amount of a food without experiencing an allergic reaction, without needing continued exposure in a therapy.
As Dr. Jonathan Spergel (Head of Allergy at Children's Hospital of Philadelphia) explains, “Desensitized means you are less allergic to a certain food. That means, if you’re desensitized to peanuts, you can’t go home and eat a peanut butter and jelly sandwich. But the goal is, if you ate part of a cookie with peanut by mistake, you would have a less severe reaction.”
What risks are involved with oral immunotherapy?
It’s important to remember that OIT requires a child to ingest doses of the food the child is allergic to.
As a result, there is still the risk that a child will develop a severe food allergic reaction during or after the treatment.
Since allergens are being introduced during treatment, there’s also an increased risk of allergic reactions in general.
Plus, not every child will become successfully desensitized to their allergen.
According to Dr. Jonathan Spergel, “Immunotherapy doesn't work for everyone. Unfortunately, about 10% still get anaphylaxis [when they consume their allergen].”
And even if they do gain the added protection, children who have undergone OIT still need to keep taking the same precautions they’ve taken previously. They must avoid the food they are allergic to, and keep two EpiPens on hand in case of a severe reaction.
As Dr. Spergel reminds us, “[OIT] is great for those that are less allergic, but they're not cured. They still need to carry epinephrine.”
OIT can also cause side effects. Most commonly, it causes GI symptoms, including abdominal pain, cramping, and vomiting.
How effective is OIT?
Based on clinical trials, and as reported by the American Academy of Allergy, Asthma, and Immunology, OIT successfully desensitizes “approximately 60 to 80% of patients.”
Dr. Spergel echoes this: “Based on the studies that have been done, whether they’re for peanut, milk, egg... we personally have done many of them --- the treatments work about 70% of the time, on average.”
But other foods haven’t been closely studied enough yet, so we don’t know if OIT will be as effective of a treatment for allergies to those foods.
And these numbers aren’t based on real-world use of OIT. Rather, they’re only based on how many trial patients have successfully passed oral food challenges.
(In oral food challenges, children are fed specific small doses of their allergen to see whether they can consume a given dose without experiencing an allergic reaction. When used to test OIT, oral food challenges measure whether someone's reaction threshold has increased above a certain amount.)
As the AAAAI states, “It is important to note that because efficacy has been measured using oral food challenges in trials, it is not yet definitively known whether desensitization can protect patients from real-world accidental exposures (e.g. prevent hospitalization or death).”
But with one type of OIT treatment, the only one approved by the FDA, results look promising. Below, we’ll break down this treatment, known as PALFORZIA.
PALFORZIA: FDA-approved peanut OIT
OIT is largely still in clinical trial stages. There is only one FDA-approved OIT treatment, PALFORZIA, which helps desensitize peanut-allergic children to peanut.
In 2020, PALFORZIA received FDA approval as an OIT treatment for children and teens with peanut allergies, ages 4-17.
The PALFORZIA treatment was developed by Aimmune Therapeutics. It consists of capsules contain peanut powder with carefully selected doses of peanut proteins.
The amount of peanut protein in a capsule starts out very low, and gradually increases to a daily maintenance dose of roughly one peanut.
PALFORZIA increases children’s reaction threshold to peanut, so they are less likely to experience an allergic reaction if they consume peanut accidentally.
But like all OIT treatments, it’s not a cure for peanut allergy. Young people undergoing the PALFORZIA treatment must still strictly avoid peanut --- they can’t start eating peanut regularly in their everyday diet.
The Phase 3 trial of PALFORZIA has shown that this OIT treatment is safe and effective for desensitization, based on an oral food challenge after a nine-month treatment period:
- Compared to the trial’s placebo group, the participants treated with PALFORZIA were "significantly less likely" to develop symptoms of a severe allergic reaction during the final food challenge.
- In the final food challenge, 58% of the young people in the PALFORZIA treatment group could consume a single 1,000 mg dose of peanut protein without experiencing an allergic reaction. Meanwhile, only 2% of the participants in the placebo group could consume that same dose without a reaction.
- Even though more than 98% of participants experienced symptoms of an allergic reaction during the trial, only mild or moderate symptoms were reported.
- No severe allergic reactions were reported during the trial.
How can I find out if OIT is right for my child?
If your child has a food allergy, your allergist will advise you on the best course of management and treatment for your child’s allergy. Currently, the standard of management is still strict avoidance of your child’s allergen and carrying an EpiPen to inject in case of a severe reaction.
Depending on the situation, though, they may be able to recommend OIT.
If an OIT treatment is available, your family and your allergist will need to decide together whether starting the treatment is worth it.
Keep in mind that you’ll need to visit the allergist regularly for check-ins, and that you’ll be regularly exposing your child to their allergen during the treatment (which could trigger an allergic reaction at any time).
Of course, OIT isn’t widely available outside of clinical trials yet. Even PALFORZIA “is only available through the PALFORZIA Risk Evaluation and Mitigation Strategy (REMS) program with a certified healthcare provider,” as the treatment’s website states.
But with recent advances in OIT treatment, it’s predicted that a larger variety of these treatments will be more widely available to children with food allergies. Time will tell!
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