Oral Immunotherapy for Food Allergy
Oral immunotherapy (OIT) is a potential treatment for food allergy. It is an emerging experimental treatment, and its benefits and harms are still being studied in clinical trials in Australia and globally.
OIT involves giving gradually increasing amounts of food allergen under medical supervision and continued daily consumption of the food allergen. If the goal of desensitisation is reached, there is a temporary increase in the amount of food allergen that can be consumed before an allergic reaction occurs.
Recent Lancet publication is a comprehensive review of OIT for peanut allergy
A meta-analysis (a method to combine data from multiple studies) of 12 OIT trials was published in the Lancet journal in April 2019. This is the most comprehensive and rigorous review of OIT for peanut allergy to date.
It reviewed the effectiveness and safety of OIT for peanut versus placebo (in OIT study but in the group that was not given peanut) or peanut avoidance (patients not in OIT study). Results showed that whilst OIT can achieve the goal of desensitisation for many people, those receiving OIT had more frequent allergic reactions, including anaphylaxis. They also required more frequent treatment with adrenaline (epinephrine) autoinjectors (such as EpiPen) than those who avoided peanut and did not receive OIT.
The Lancet publication supports the need for improved food allergy treatment approaches with an enhanced safety profile and trials focused on patient-important outcomes. ASCIA also supports this approach.
Food allergy occurs in around 5-10% of children, and 2-4% of adults in Australia and New Zealand. The most common foods that cause allergic reactions are egg, peanut, cow's milk (dairy), tree nuts, soy, sesame, wheat, fish and other seafood (crustaceans).
Whilst most food allergies result in mild to moderate allergic reactions, some food allergies can be severe, resulting in potentially life-threatening allergic reactions known as anaphylaxis.
Most food allergies in children are not severe and some may be 'outgrown' with time, studies have shown that 5% of children still have their food allergy at five years of age. Peanut, tree nut, seed and crustacean allergies are less likely to be ‘outgrown’ and tend to be lifelong allergies. When food allergy develops for the first time in adults, it usually persists.
The possible benefits from OIT are desensitisation and sustained unresponsiveness
Published trials show that OIT for food allergy can result in desensitisation in many people, but most do not show sustained unresponsiveness:
- Sustained unresponsiveness means that a person can still consume the food allergen after a period of avoidance or stopping OIT, without having an allergic reaction. This may sometimes be called “ongoing tolerance”.
- Desensitisation is a temporary state that allows a person to consume more of the food allergen than they could prior to OIT. This requires the food allergen to be consumed regularly, without stopping.
Safety and effectiveness of OIT
It is important that people with food allergy and their families are aware that OIT methods are not currently standardised or approved for routine treatment of food allergy globally. There are concerns about potential harm outweighing the benefits in people with severe food allergy, as well as considerable cost implications.
There are many social media posts about the use of OIT as a potential treatment for food allergy, particularly in the USA. However, currently there are no OIT methods approved by the Food and Drug Administration (FDA) to treat food allergy in the USA. These methods are still under review and until these are approved, experts do not recommend OIT for use outside of clinical trials.
The recent Lancet publication shows that current peanut OIT methods do not satisfy the clinical aim of less allergic reactions, including anaphylaxis. Instead more allergic and adverse reactions were reported with OIT compared with avoidance or placebo.
Allergic reactions can still occur due to accidental exposure, or due to the OIT itself. There may also be other complications of OIT, for example, inflammation of the oesophagus, which is the muscular tube that connects the mouth to the stomach.
Currently there are several clinical trials of OIT and other treatments for food allergy underway in Australia and other countries. In some of these trials, OIT is combined with another component that may help to make allergic reactions less severe, improve safety and encourage tolerance. The trials aim to develop standardised and proven methods to maximise benefit and reduce the risk of potential harm in people with severe food allergy. These trials are all hospital based due to high rates of allergic reactions.
Until these trials are completed, with methods, safety and effectiveness determined, ASCIA recommends that OIT for food allergy should not be performed outside of clinical trials.
Current ASCIA recommendations for management of food allergy
Until OIT and other treatments for food allergy are proven and standardised for routine use, and shown to be safe to undertake at home, avoidance of confirmed food allergens is recommended for the management of food allergy. If OIT to peanut (and potentially other foods) is undertaken, it is also important that people with food allergy and their families are told of the increased likelihood of allergic reactions and anaphylaxis and be prepared for these events. Current OIT methods are not a cure for food allergy.
It is therefore important for people with food allergy and their families to:
- Know the signs and symptoms of mild to moderate and severe allergic reactions (anaphylaxis).
- Know what to do when an allergic reaction occurs.
- Read and understand food labels for food allergy.
- Inform wait staff that they have food allergy when eating out.
- Be aware of cross contamination of food allergens when preparing food.
- Carry their adrenaline (epinephrine) autoinjector (if prescribed), and an ASCIA Action Plan for Anaphylaxis.
Further information and support
Lancet publication (abstract) www.thelancet.com/journals/lancet/article/PIIS0140-6736(19)30420-9/fulltext
Information about food allergy: www.allergy.org.au/patients/food-allergy
Information about venom or aeroallergen immunotherapy www.allergy.org.au/patients/allergy-treatment
© ASCIA 2019
ASCIA is the peak professional body of clinical immunology/allergy specialists in Australia and New Zealand.
ASCIA resources are based on published literature and expert review, however, they are not intended to replace medical advice. The content of ASCIA resources is not influenced by any commercial organisations.
For more information go to www.allergy.org.au
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Updated May 2019