Peanut Allergy Desensitization

Transcription

1 Peanut Allergy Desensitization DERRICK R. WARD, MD KANSAS CITY ALLERGY AND ASTHMA ASSOCIATES KAAP SPRING CME MEETING APRIL 24, 2015 Disclosures Speakers Bureau Teva pharmaceuticals Consultant None Research None Stock No major stock holdings Objectives Recognize the current epidemiology of food allergy Identify the current standards for food allergy testing Identify potential candidates for peanut desensitization Discuss the peanut desensitization/oit protocol Discuss the efficacy of peanut OIT Identify potential safety concerns with OIT 1

2 Food Allergy Epidemiology 8% of children have at least one food allergy 1 Eight foods account for 90% of all FAs. Peanut, milk, egg, wheat, soybean, tree nuts, fish and shellfish 300,000 ambulatory care visits for FA per year in children under 18 y/o 2 FA is the leading cause of anaphylaxis outside the hospital setting Gupta, R, et al. The Prevalence, Severity and Distribution of Childhood Food Allergy in the United States. Pediatrics 2011; /ped Sampson HA. Anaphylaxis and emergency treatment. J Pediatrics. 2004; 111: Food Allergy Testing Pearls Only order specific IgE lab testing or refer for allergy skin testing. Why should you avoid ordering food panels? 50% PPV if there is a low pre-test probability Strictly avoid unproven testing, especially IgG testing Food allergy: A practice parameter update 2014 Sampson, Hugh A.Sampson, Hugh A.Bernstein, DavidSampson, Hugh A. et al. Journal of Allergy and Clinical Immunology, Volume 134, Issue 5, e43 Peanut Allergy Prevalence: 1-2% in the U.S. 1 Highest prevalence in children <3 y/o ~20% of PN allergic kids will become tolerant by school-age 2 Reactions are non-stereotypical in nature and specific IgE level does not predict the potential severity of a reaction 1. Gupta, R, et al. The Prevalence, Severity and Distribution of Childhood Food Allergy in the United States. Pediatrics 2011; /ped Skolnick HS, et al., The natural history of peanut allergy. JACI 2001;107:

3 Peanut Allergy Accidental exposure occurs in ~12% of PN allergic patients per year 1 Peanut is the most common cause of food allergy related death 20 of 32 deaths in one study 2 Traditional treatment strategies: Avoid Treat reactions when needed 1. Nguyen-Luu, et al. Inadvertant exposures in children with peanut allergy. Pediatr Allergy Immunol 2012; 23: Bock SA, et al. Fatalities due to anaphylactic reactions to food. JACI 2001; 107:191-3 Peanut Allergy WHAT OTHER TREATMENT OPTIONS ARE THERE?? Peanut allergy desensitization AKA Oral immunotherapy (OIT) Alternative for some patients to the traditional treatment approach OIT is not an established treatment and is not yet mainstream. Only 2 allergists in Kansas and Missouri combined offer OIT However, use of OIT is supported by an extensive body of literature through case studies and clinical trials. 3

4 Peanut allergy desensitization Mansfield L. Successful oral desensitization for systemic peanut allergy. Ann Allergy Asthma Immunol 2006; 97:266-7 Anagnostou K, et al. Efficacy and safety of high-dose peanut oral immunotherapy with factors predicting outcome. Clin Exp Allergy 2011; 41: Yu GP, et al. The safety of peanut oral immunotherapy in peanut allergic subjects in a single center trial. Int Arch Allergy Immunol 2012; 159: Sheikh A, et al. Oral immunotherapy for the treatment of peanut allergy: systematic review of six case series studies. Prim Care Respir J 2012; 21:41-9 Hofmann AM, et al. Safety of a peanut oral immunotherapy protocol in children with peanut allergy. J Allergy Clin Immunol 2009; 124:286-91, 291.e1-6. Fleischer DM, et al. Consortium of Food Allergy Research. Sublingual immunotherapy for peanut allergy: a randomized, double-blind, placebo-controlled multicenter trial. J Allergy Clin Immunol 2013; 131: e1-7 Patient Selection 5 years old is our current minimum age No peanut IgE value is too high or too low Patients with multiple food allergies are still candidates Weigh the likelihood of them becoming tolerant on their own If the peanut IgE and Ara h 2 IgE are marginal or the history is marginal, an oral challenge is necessary Adherence to the protocol is an absolute necessity Protocol Weeks 1-6 Peanut flour mixed with Kool-Aid Weeks 7-11 Peanut flour mixed with any vehicle Weeks Peanuts or equivalent (peanut butter, flour, etc) Office dosing vs. home dosing Typically 4-6 months to completion 4

5 Protocol Day one 6-8 hours and 20 total doses Dose increased every minutes Escalation days Weekly increase in dosing x ~21 weeks Each office visit is ~ 1 hour They home dose BID between escalation days Maintenance phase 8 peanuts once daily Peanut OIT Efficacy ~85% of patients reach the maintenance dose Burks, et al., A randomized controlled study of peanut oral immunotherapy: Clinical desensitization and modulation of the allergic response. JACI 2011; 127: patients 16 reached maintenance doses Wasserman, et al., Oral Immunotherapy for Peanut Allergy: Multipractice Experience with Epinephrine-treated Reactions. JACI In Practice 2014; 2: Pooled data from 5 private practices 352 patients 298 reached maintenance doses Efficacy Dr. Wasserman s clinic data as of May 2014: 228 patients have begun OIT 193 (85%) have reached maintenance 97% of patients have continued maintenance dosing for at least 3 years Dr. Wasserman current OIT numbers: Peanut 119 on maintenance; 44 escalating Milk 57 on maintenance; 6 escalating Egg 37 on maintenance; 3 escalating Wheat 2 on maintenance; 0 escalating Tree nuts 3 on maintenance; 9 escalating 5

6 Safety & Side Effects Wasserman et al. 1 5 Private practices 352 patients 240,351 doses of peanut, peanut butter or peanut flour 95 reactions treated with epinephrine 0.2 ETRs per 1000 doses 1 site excluded due to differing criteria for giving epinephrine SCIT systemic reaction rate 0.1% 1. Wasserman, et al., Oral Immunotherapy for Peanut Allergy: Multipractice Experience with Epinephrine-treated Reactions. JACI In Practice 2014; 2: Safety & Side Effects Most common SE are GI related Abdominal pain, nausea, reflux More severe reactions are treated like any other allergic reaction Eosinophilic esophagitis develops in ~10% of pts Thank You