Adults living with the fear of severe peanut allergies might finally have hope. A groundbreaking trial has shown that carefully supervised daily peanut exposure can desensitize most adults, allowing them to eat peanuts without a reaction.
The GUPI trial, the first to focus solely on adults, revealed that two-thirds of participants could safely consume the equivalent of five peanuts after gradual dose increases. Many reported dramatic improvements in quality of life, shedding years of fear and anxiety, with some calling the experience “life-changing.”
Promising Breakthrough in Peanut Allergy Desensitization
The first clinical trial to test whether adults with peanut allergies can be desensitized has delivered promising results. In the study, two-thirds of participants were able to consume the equivalent of five peanuts without experiencing an allergic reaction.
Known as the Grown Up Peanut Immunotherapy (GUPI) trial, this is the first study conducted exclusively in adults with severe peanut allergies. It tested whether daily, carefully supervised doses of peanuts could be safely tolerated over time.
The method, called oral immunotherapy, has already proven effective in infants and children through previous trials around the world. Now, this new adult-focused research has been published in the journal Allergy by a team from King’s College London and Guy’s and St Thomas’ NHS Foundation Trust. The study was funded by the National Institute for Health and Care Research (NIHR) through its Research for Patient Benefit Programme.
Relieving the Burden of Constant Fear
Professor Stephen Till, Chief Investigator and Professor of Allergy at King’s College London, explained: “Constant fear of life-threatening reactions places a huge burden on people with peanut allergy. The only way to manage a peanut allergy is strict avoidance and treatment of allergic reactions, including with adrenaline.
“Although peanut immunotherapy is known to be effective in children, this trial provides preliminary evidence that adults can also be desensitised and that this improves quality of life. The average tolerated dose of peanuts increased 100-fold over the course of the trial.”
The Phase II trial recruited twenty-one adults between 18 and 40 with a clinical diagnosis of peanut allergy at Guy’s and St Thomas’ NHS Foundation Trust. Allergy was confirmed via skin prick test, blood test, and then an oral food challenge.
Carefully Monitored Early Dosing
In a clinical setting, participants received the first dose of 0.8mg peanut flour mixed in with food, then 1.5 mg 30 minutes later followed by 3mg a further 30 minutes later.
Participants who tolerated 1.5mg or 3mg of peanut flour continued on a daily dose at home for 2 weeks. This is the equivalent of 0.5-1% of a whole peanut.
Then participants returned at 2-weekly intervals for supervised doses of more peanut protein, increasing from 6mg (around 1/40th of a whole peanut) to 1g (four whole peanuts). If participants could tolerate 50-100mg of peanut protein, participants were switched to eating whole peanuts, peanut butter or peanut products, with the first dose being under supervision of the clinical team.
Testing Final Tolerance and Daily Maintenance
Once participants achieved a daily dose of 1g, they remained on this dose for at least four weeks before undergoing a double‐blind placebo‐controlled food challenge. This involved being given increasing doses of either peanut or placebo (dummy) on separate days under close supervision to test their tolerance. Participants then continued daily dosing for at least three months before exiting the trial as well as the option of continuing post-study.
Results showed that 67% of participants were able to consume at least 1.4g of peanut protein – the equivalent of five peanuts – without reacting. Participants of the trial could then consume peanuts every day at home to remain desensitized.
Professor Till said: “We are very pleased with the results. The efficacy rate is broadly in line with peanut oral immunotherapy trials in children. The next stage of the research will be confirming this in larger trials, and also identifying the group of adult patients who would most likely benefit from oral immunotherapy, and see whether it can lead to long-term tolerance in this age group.”
Life-Changing Impact on Quality of Life
Lead author specialist Allergy Dietitian Hannah Hunter from Guy’s and St Thomas’ NHS Foundation Trust said: “Living with peanut allergy is a huge burden due to the need for constant vigilance and the risk of accidental exposures. Everyday situations such as eating in restaurants and social events are anxiety-provoking, and our patients tell us that the condition also affects travel choices and career options. We found that quality of life significantly improved after oral immunotherapy, and fear of food also decreased. Many participants who completed the trial told us that the treatment had been life-changing and they were no longer living in fear.”
A Participant’s Perspective: Freedom from Fear
Chris, 28, took part in the trial. He was diagnosed with a peanut allergy as a baby and jumped at the chance of taking part in the trial.
He said, “I’m so proud to have been part of this trial and so happy to say that I used to be allergic to peanuts, but thanks to this trial, this is no longer a concern. My family and I were always anxious that even a trace of peanut could be life-threatening. The trial was an interesting experience because all of my life, I had associated the taste and smell of peanuts with fear and death.
“I started with a small amount of peanut flour with yogurt, and by the end of the trial, I could eat four peanuts in one sitting. Now, I have four peanuts every day with my breakfast to maintain my immunity. Before, a tiny mistake could have life-threatening impacts, but now I don’t have the fear that I might collapse and die from eating a takeaway.”
Reference: “Oral Immunotherapy in Peanut-Allergic Adults Using Real-World Materials” by Hannah Hunter, Kok Loong Ue, Victoria Cornelius, Ching Ching Yung, Iason Thomas, Olympia Tsilochristou, Janice Layhadi, Leonard Q. C. Siew, Carina Venter, Mohamed H. Shamji and Stephen J. Till, 23 April 2025, Allergy.
DOI: 10.1111/all.16493
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