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Rapid Omalizumab and Peanut Immunotherapy in Adults with Peanut Allergy: OPAL 2

AIFA Professor Ann Kupa Food Allergy Research Grant

Dr Jacqueline Loprete

St Vincent's Hospital, Sydney

Research team: Prof Andrew Carr, Dr Winnie Tong, Ms Robyn Richardson, Mr Jonathan Montemayor, Mr Jamie Rogers, Dr Karran Pathmanandavel (St Vincent’s Hospital)

Dr Jacqueline LopretePeanut is one of the most frequent causes of food allergy in Australia, affecting 1 in 100 adults1. Peanut allergy also affects approximately 3% of children. Given that only 20% of children will grow out of their peanut allergy2, it follows that the proportion of adults living with peanut allergy will only increase over time.

Not only is peanut allergy common, but it caused almost 20% of deaths in adults from food-related anaphylaxis in Australia between 1997 and 20133. These deaths all occurred in patients with a known allergy to peanut, including patients who previously had anaphylaxis to peanut and carried an adrenaline injector that can abort anaphylaxis. Adults are at greater risk than children of severe reactions to accidental peanut exposure3.

Peanut allergy can also have significant psychosocial impacts. It limits social interactions and increases anxiety in patients and their families4. The only recommended treatment for the prevention of peanut allergy in adults is strict avoidance, including of products that are labelled as “may contain traces of peanut”. However, the risk of hidden allergens in packaged products and food prepared outside of the home cannot be discounted5. Avoidance is supplemented by carrying an adrenaline injector in case of accidental exposure. This constant need for vigilance is what drives the psychosocial stress for those with a peanut allergy and their loved ones.

One tool available to treat IgE-mediated reactions is immunotherapy. Allergen immunotherapy involves exposing an individual to gradually increasing amounts of the substance to which they are allergic to induce immune tolerance, which allows reactions to become less severe or to disappear completely. With non-food-induced allergy, allergen immunotherapy is proven to be an effective treatment (e.g. immunotherapy for bee venom anaphylaxis is life-saving)6 and is the standard of care.

There is limited data regarding food immunotherapy in adults. The PALISADE group demonstrated efficacy in 40% of adults compared to 65% of children7. This 40% rate was also lower than in other studies of peanut immunotherapy in children8-10. A systematic review food immunotherapy studies showed a significant risk reduction in children but not in adults11.

The reason for the lower efficacy in adults compared to children is unclear. The dropout of adults in food immunotherapy studies is higher than children12, perhaps due to more frequent and more severe adverse reactions13. Immunotherapy in children may also be more successful because the younger immune system has more plasticity.

The recently completed Combining Peanut Oral Immunotherapy and Omalizumab in Adults with Peanut Allergy (OPAL) Study was an Australian-first, prospective, single-arm study. It recruited adults who reacted to less than one peanut kernel (300mg of peanut protein). OPAL evaluated the usefulness of omalizumab, a medication targeted against the IgE protein responsible for triggering allergic reactions, plus peanut immunotherapy.

The OPAL study demonstrated comparable and possibly superior efficacy and comparable safety when compared indirectly to previously published studies in adults. However, the OPAL protocol required 14 visits over 6 months, which for most adults translated to 14 days off work. A shorter protocol is essential for these results to be translated into routine clinical practice. We propose a new study with fewer visits (7 vs. 14) over a shorter duration (12 vs. 24 weeks).

The primary aim of this study is to assess if a rapid protocol of omalizumab and peanut immunotherapy has similar efficacy and safety as the established OPAL protocol. The team also aims to assess the incidence and severity of reactions to a peanut challenge after 36 weeks of maintenance oral peanut immunotherapy, the frequency and severity of accidental peanut exposure, changes in quality-of-life markers in people undergoing peanut immunotherapy, changes in immunological markers in individuals undergoing immunotherapy, and to compare these outcomes to the results of the OPAL study.

AIFA acknowledges the support of Professor Ann Kupa for this Food Allergy Research Grant of $20,000

References

1. Tang ML, Mullins RJ. Food allergy: is prevalence increasing? Intern Med J. 2017;47(3):256-61.
2. Australasian Society of Clinical Immunology and Allergy. Peanut, tree nut and seed allergy 2017 [Available from: https://www.allergy.org.au/patients/food-allergy/peanut-tree-nut-and-seed-allergy.
3. Mullins RJ, Wainstein BK, Barnes EH, Liew WK, Campbell DE. Increases in anaphylaxis fatalities in Australia from 1997 to 2013. Clin Exp Allergy. 2016;46(8):1099-110.
4. Stensgaard A, Bindslev-Jensen C, Nielsen D, Munch M, DunnGalvin A. Quality of life in childhood, adolescence and adult food allergy: Patient and parent perspectives. Clin Exp Allergy. 2017;47(4):530-9.
5. Zurzolo GA, Allen KJ, Peters RL, Dharmage SC, Tang MLK, Said M, et al. Self-reported anaphylaxis to packaged foods in Australia. J Allergy Clin Immunol Pract. 2019;7(2):687-9.
6. Australasian Society for Clinical Immunology and Allergy. Venom Immunotherapy: A Guide for Clinical Immunology/Allergy Specialists 2019 [Available from:
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8. Vickery BP, Scurlock AM, Kulis M, Steele PH, Kamilaris J, Berglund JP, et al. Sustained unresponsiveness to peanut in subjects who have completed peanut oral immunotherapy. J Allergy Clin Immunol. 2014;133(2):468-75.
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10. Tang ML, Ponsonby AL, Orsini F, Tey D, Robinson M, Su EL, et al. Administration of a probiotic with peanut oral immunotherapy: A randomized trial. J Allergy Clin Immunol. 2015;135(3):737-44.e8.
11. Nurmatov U, Dhami S, Arasi S, Pajno GB, Fernandez-Rivas M, Muraro A, et al. Allergen immunotherapy for IgE-mediated food allergy: a systematic review and meta-analysis. Allergy. 2017;72(8):1133-47.
12. Epstein-Rigbi Na, Levy MB, Nachshon L, Koren Y, Katz Y, Goldberg MR, et al. Efficacy and safety of food allergy oral immunotherapy in adults. Allergy. 2023;78(3):803-11.
13. Zhu R, Robertson K, Protudjer JLP, Macikunas A, Kim R, Jeimy S, et al. Impact of age on adherence and efficacy of peanut oral-immunotherapy using a standardized protocol. Pediatric Allergy and Immunology. 2021;32(4):783-6.