Researchers at McMaster University and St. Joseph’s Healthcare Hamilton have found that it is safer for individuals with peanut allergies to avoid peanuts altogether, including current oral immunotherapy (OIT) designed to gradually desensitize allergic reactions to peanuts.
In a systematic review and network meta-analysis, which analyzed twelve previous studies on OIT to treat peanut allergy, researchers found that those taking OIT experienced more side effects, including anaphylaxis and other allergic reactions compared to those who simply avoided peanuts. The analyzed studies included over 1,000 patients with a peanut allergy, who were followed for up to nearly six years.
Approximately 2% of children and 1% of adults in high income countries are affected by some degree of peanut allergy.
“Millions of people around the world have a peanut allergy and there’s growing awareness of its negative effects, from health-related quality of life to a reaction that could result in death,” said Derek Chu, first author of the study. Dr. Chu is a fellow in clinical immunology and allergy at McMaster University.
“When you look at the data, it is clear that people who were on peanut oral immunotherapy, known as OIT, had many more allergic reactions compared to those that only avoided peanut, both mild ones such as vomiting all the way to severe reactions like anaphylaxis. This was despite oral immunotherapy being able to cause desensitization,” noted Dr. Chu.
Dr. Derek Chu is a fellow in clinical immunology and allergy at McMaster University. Photo courtesy McMaster University.
The study, published today in The Lancet, is believed to be the first rigorous systematic synthesis of all relevant data on OIT for peanut allergy. Researchers consistently found that protection from OIT was inconsistent across clinical and real-world situations. Patients were able to eat peanut in a clinical setting without incident, but experienced real-world reactions. These paradoxical findings were explained through differences in the way people eat in the real-world compared to how they eat in a clinical setting.
“It means that although this experimental approach may be promising,” said Dr. Chu, “there are currently some significant limitations. This is just the first generation of experimental approaches to treatment.”
According to Dr. Susan Waserman, Director of the Adverse Reactions Clinic at St. Joseph’s Healthcare Hamilton, use of peanut OIT “comes with a risk of reactions, and many patients may opt for avoidance. Peanut allergic individuals need choice and accurate information, which should include this study reported in The Lancet.”
An interactive Summary of Findings table from the research is available for patients, clinicians, and policy makers. It can be accessed at bit.ly/LancetOIT. The table includes explanations in plain language.
OIT for peanut allergy is currently an experimental therapy being considered by the US Food and Drug Administration and the European Medicines Agency, Dr. Chu noted.
For patients, healthcare providers, and policy makers, the findings show that safer peanut allergy treatments, rigorously tested through randomized controlled trials, are needed before these treatments can be used routinely.
For researchers, the findings demonstrate the disconnect between in-clinic testing of allergic reactions and real-world, everyday conditions that lead to exposure. The authors recommend that future studies on allergy treatments should focus on the risk and frequency of adverse reactions from real-world exposures, rather than simply reactions from in-clinic, supervised food challenges.
No external funding was provided for the study.