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Sustained unresponsiveness to peanut in subjects who have completed peanut oral immunotherapy. 2014

J Allergy Clin Immunol. Author manuscript; available in PMC 2015 Feb 1.
Published in final edited form as:
PMCID: PMC3960331
NIHMSID: NIHMS541850

Sustained unresponsiveness to peanut in subjects who have completed peanut oral immunotherapy

Brian P. Vickery, MD,1 Amy M. Scurlock, MD,2 Michael Kulis, PhD,1 Pamela H. Steele, CPNP,1 Janet Kamilaris, RN,1Jelena P. Berglund, PhD,3 Caitlin Burk, BA,1 Anne Hiegel, RN,2 Suzanna Carlisle, RN,2 Lynn Christie, RD,2 Tamara T. Perry, MD,2 Robbie D. Pesek, MD,2 Saira Sheikh, MD,1 Yamini Virkud, MD, MA,4 P. Brian Smith, MD, MHS, MPH,4Mohamed H. Shamji, MD,5 Stephen R. Durham, MD,5 Stacie M. Jones, MD,2 and A. Wesley Burks, MD1
Author information ► Copyright and License information ►
The publisher’s final edited version of this article is available at J Allergy Clin Immunol

Abstract

Background

Although peanut oral immunotherapy (OIT) has been conclusively shown to cause desensitization, it is currently unknown whether clinical protection persists after stopping therapy.

Objective

Our primary objective was to determine whether peanut OIT can induce sustained unresponsiveness following withdrawal of OIT.

Methods

We conducted a pilot clinical trial of peanut OIT at two U.S. centers. Subjects aged 1–16 were recruited and treated for up to five years with peanut OIT. The protocol was modified over time to permit dose increases to a maximum of 4000 mg peanut protein/day. Blood was collected at multiple time points. Clinical endpoints were measured with 5000 mg double-blinded, placebo-controlled food challenges once specific criteria were met.

Results

Of the 39 subjects originally enrolled, 24 completed the protocol and had evaluable outcomes. 12/24 (50%) successfully passed a challenge one month after stopping OIT and achieved sustained unresponsiveness. Peanut was added to the diet. At baseline and the time of challenge, such subjects had smaller skin tests as well as lower IgE levels specific for peanut, Ara h 1, and Ara h 2, and lower ratios of peanut-specific: total IgE, compared to subjects not passing. There were no differences in peanut IgG4 levels or functional activity at end-of-study.

Conclusions

This is the first demonstration of sustained unresponsiveness after peanut OIT, occurring in half of subjects treated up to five years. OIT favorably modified the peanut-specific immune response in all subjects completing the protocol. Smaller skin tests and lower allergen-specific IgE levels were predictive of successful outcome.

Keywords: Peanut allergy, Oral immunotherapy, Desensitization, Tolerance, Sustained Unresponsiveness

LINK TO: Sustained unresponsiveness to peanut in subjects who have completed peanut oral immunotherapy. J Allergy Clin Immunol. 2014 Feb;133(2):468-75.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3960331/

“Layperson explanation”

This study measured “Sustained Unresponsiveness” after OIT. “Sustained unresponsiveness” is a term which means “no reaction” (unresponsive) to the allergen in a food challenge after a patient stops taking their daily maintenance dose. The effect of “not responding” is sustained even after the patient stops regular eating of the allergen.
In this study, they started recruiting patients in March 2007, with a final 39 patients, 29 of whom completed the initial study. Overall, 27 of 29 (93%) reached the total peanut dose of 3.9 g with no more than mild symptoms, suggesting successful desensitization to peanut protein. Two subjects did not ingest the maximal dose and stopped after 2.1 g. One stopped because of parental anxiety, and the other because of mild urticaria and 1 vomiting episode. See the original study, published in 2009:
https://oit101.org/research/clinical-efficacy-and-immune-regulation-with-peanut-oral-immunotherapy-2009/ 
With this final part of the study they were down to 24 patients from the original 39: 6 who withdrew due to symptoms and 9 who withdrew for personal and other reasons.
After they passed a successful food challenge, all of them stopped daily dosing for 4 weeks. Then they did a food challenge. 50% of the 24 patients  passed the challenge and were called “Treatment Successes” and had reached  “sustained unresponsiveness”. If they passed, they were advised to incorporate peanut into the diet “at their pleasure”  at least several days per week instead of dosing daily.

Notably, the other half who did not  sustained unresponsiveness were called “Treatment Failures,” BUT were they really? They were still able to consume a much larger amount of peanut, with less severe reactions, than they could at the study’s outset. Note that the half that “failed” being able to eat unlimited peanuts after being off therapy for a month were still able to eat 10-12 peanuts with the majority being able to eat 12!!! Not one subject in the study ate less than 10 peanuts after totally discontinuing peanut ingestion for a month. The half that were treatment “failures” resumed OIT. So half the kids started losing desensitization after being off OIT for a month but 10-12 peanuts is certainly way more than bite-proof /CC protection.

You can read an easy summary of these major study here: http://allergicliving.com/2014/02/05/first-long-term-study-of-peanut-therapy-shows-lasting-protection/

“Our findings suggest for the first time that in peanut-allergic patients, long-term treatment with oral immunotherapy may produce sustained benefits allowing introduction of peanut back into the diet,” said study author Dr. Brian Vickery, Assistant Professor Of Pediatrics at the University of North Carolina.”

in Key Studies & Publications. Medical Journals, 1908-Present, Medical Journals: OIT Publications 2014

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