Peanut Oral Immunotherapy May Increase Risk for Anaphylaxis

Oral immunotherapy (OIT) for patients with peanut allergy increases allergic and anaphylactic reactions compared with placebo or avoidance, according to a systematic review and meta-analysis published online April 25 in The Lancet.

"This meta-analysis 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," write Derek K. Chu, MD, PhD, McMaster University, Hamilton, Ontario, Canada, and colleagues.

Chu and colleagues evaluated 12 randomized controlled trials that included 1041 participants who were a median age of 8.7 years. The median starting dose of peanut protein in the studies was 0.5 mg daily and the median daily maintenance dose was 2000 mg (about four peanuts).

Most of the included studies relied on an in-clinic food challenge (provocation test) as a surrogate marker for prevention of out-of-clinic allergic reactions. As part of their analysis, Chu and colleagues prioritized patient-centered outcomes, which included epinephrine use, involvement of two or more organ systems following possible allergen exposure, isolated hypotension following known allergen exposure, and quality of life.

The researchers found that although the likelihood of passing the in-clinic test was greater among patients in the OIT group compared with the no OIT group (nine trials; relative risk [RR], 12.42; 95% CI, 6.82 - 22.61; P < 0.0001), so was the risk for anaphylactic reactions (risk ratio [RR], 3.12; 95% CI, 1.76 - 5.55).

Compared with a historical baseline risk of 71 episodes of anaphylaxis per 1000 patients, this meant that OIT was associated with 151 (95% CI, 54 - 323) more episodes of anaphylaxis per 1000 patients.

Chu and colleagues also note an increased risk for anaphylaxis frequency (RR, 2.72; 95% CI, 1.57 - 4.72) and epinephrine use (RR, 2.21; 95% CI, 1.27 - 3.83) among patients in the OIT group compared with no OIT. Further, they found that the risk of an anaphylaxis complication was similar regardless of the phase of treatment (ie, build-up versus maintenance).

Patient-Centered Outcomes Show Need for Safer Treatment

In an accompanying editorial, Graham Roberts, DM, and Elizabeth Angier, MBBS, from the University of Southampton, UK, note that the patient-centered endpoint used by Chu and colleagues, "arguably provides a much better summary of a patient's experience in day-to-day living than one oral peanut challenge."

Roberts and Angier note, however, that the trials did not consider the differing patterns of anaphylactic events. For example, patients in the daily OIT group would have been more likely to experience complications at home as opposed to patients in the comparator groups who would potentially experience these issues away from home and in less controlled settings.

"Trading treatment-related side effects at home for allergic reactions to accidental exposures out of the house (ie, in social situations) might be beneficial for some patients," the editorialists write.

"However, it is not clear which patients might benefit most and what the relative balance of reactions in and out of patients' homes would be," they conclude.

Three of the study authors are part of an ongoing peanut OIT study funded by AllerGen NCE. One author has reported receiving grants from the US National Institutes of Health, Astellas, Aimmune, DBV Technologies, Sanofi, and Regeneron, and personal fees from the American Academy of Allergy, Asthma & Immunology and UpToDate outside the submitted work. One author has reported receiving grants from Aimmune and personal fees from Pfizer, Mylan, and Sanofi outside the submitted work. The editorialists have disclosed no relevant financial relationships.

Lancet. Published online April 25, 2019. Abstract, Editorial

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