Peanut Allergy Oral Immunotherapy Increases Allergic Reactions

Despite inducing desensitization, peanut allergy oral immunotherapy increases a patient’s risk of allergic reactions compared with avoidance or placebo, according to a recent study.

Investigators examined 12 randomized clinical trials that included more than 1000 patients and found that oral immunotherapy was associated with a greater risk of anaphylaxis, epinephrine use, and serious adverse events compared to avoidance or placebo.

Investigators search MEDLINE, EMBASE, Cochrane Controlled Register of Trials, Latin American and Caribbean Health Sciences Literature, China National Knowledge Infrastructure, WHO’s Clinical Trials Registry Platform, US Food and Drug Administration (FDA), and European Medicines Agency databases for published and unpublished randomized clinical trials comparing oral immunotherapy with placebo or allergen avoidance for treatment of peanut allergy. They identified 1624 records and 12 of them were chosen for the study. Reasons for exclusion included relevance, study design, duplication, had the wrong intervention, and several other reasons.

Study outcomes identified by investigators included peanut-induced anaphylaxis, peanut induced allergic reactions, epinephrine use, and quality of life. In total, the studies examined included 1041 participants undergoing peanut oral immunotherapy.

In 9 trials involving 950 participants, which reported anaphylaxis data, oral immunotherapy increased the risk of anaphylaxis compared with no oral immunotherapy. Authors noted this effect was seen irrespective of entry challenge threshold, starting or target dose, oral immunotherapy duration, age, control group assignment, or whether the formulation was a proprietary product or not. In 9 trials involving 984 participants, which reported epinephrine use, oral immunotherapy compared with no oral immunotherapy increased the risk of epinephrine use and its frequency over 936 person years.

Investigators note that the frequency of anaphylaxis was about 3 times higher (22.2% versus 7.1%) in the group with oral immunotherapy compared to the group without. Epinephrine use was around 2 times greater in those who underwent oral immunotherapy, from 3.7% without to 8.2% with. The number of serious adverse events was about double as well, from 6.2% without to 11.9% with.

Allergic reactions involving the gastrointestinal tract, skin and mucous membranes, nose, and lungs also increased.

Authors noted that while participants received peanut oral immunotherapy were more likely to experience allergic and anaphylactic reactions, treatment effectively inducing desensitization as shown in supervised challenges.

Authors noted several limitations within their study including the small number of patients and studies that did not report all data for all patients. They also noted that the findings of their study would benefit from additional studies.

Study authors wrote that their results legitimize the need for additional studies to further explore the impact of oral immunotherapy and what improvements in safety can be made to make the treatment most effective for patients.

“Our study synthesises all randomized clinical trials comparing peanut oral immunotherapy to no immunotherapy in order to generate the highest quality evidence to inform decision making. It shows that current peanut oral immunotherapy regimens can achieve the immunological goal of desensitization, but that this outcome does not translate into achieving the clinical and patient-desired aim of less allergic reactions and anaphylaxis over time,” wrote lead author Derek Chu, MD, PhD, FRCPC, professor at McMaster University, Canada.

This study, titled “Oral immunotherapy for peanut allergy (PACE): a systematic review and meta-analysis of efficacy and safety,” was published in The Lancet.