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1 Oral Immunotherapy Wesley Burks, M.D. Professor and Chair Department of Pediatrics University of North Carolina.

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Presentation on theme: "1 Oral Immunotherapy Wesley Burks, M.D. Professor and Chair Department of Pediatrics University of North Carolina."— Presentation transcript:

1 1 Oral Immunotherapy Wesley Burks, M.D. Professor and Chair Department of Pediatrics University of North Carolina

2 FACULTY DISCLOSURE FINANCIAL INTERESTS I have disclosed below information about all organizations and commercial interests, other than my employer, from which I or a member of my immediate family or household receive remuneration in any amount (including consulting fees, grants, honoraria, investments, etc.) or invest money which may create or be perceived as a conflict of interest. Name of Organization Nature of Relationship AllerteinMinority Stockholder Dannon Co. ProbioticsAdvisory Board ExploraMedConsultant IntellijectConsultant Mast Cell, Inc.Minority Stockholder McNeil NutritionalsConsultant NovartisConsultant NutriciaExpert Panel Schering-PloughConsultant RESEARCH INTERESTS I have disclosed below information about all organizations which support research projects for which I or a member of my immediate family or household serve as an investigator. Name of Organization Nature of Relationship National Institutes of HealthGrantee Food Allergy and Anaphylaxis NetworkGrantee SHAGrantee FAIGrantee National Peanut BoardGrantee Wallace FoundationGrantee

3 3 Background: Food allergy Prevalence: –3 million school age children (3.9%) –18% increase since 1997 Branum 2009 Pediatrics. 124: “evolved dependence” – changes in commensals, subclinical infections, asymptomatic carriers Rook – CEI most common food allergens in U.S. –Milk, egg, peanut, tree nuts, shellfish, soy, wheat Peanut allergy –Prevalence ~1% –Most common cause of anaphylaxis in children presenting to the ED –Most common cause of fatal food anaphylaxis Standard of care –Avoidance of only foods appropriately diagnosed –Self-injectable epinephrine/antihistamines Vander Leek, J Peds 2000 Bock, J Allergy Clin Immunol 2007

4 Food allergy and what parents hear

5 Nowak-Wegrzyn JACI March 2011 Approaches to food allergy immunotherapy

6 Initial food allergy immunotherapy Goals of treatment are two-fold –Clinical desensitization tolerate more food before an accidental reaction –Eventual clinical tolerance off treatment Goals of research on food allergy treatment –Identify the mechanism(s) of the changes brought on by the treatment –Identify immunologic markers associated with the treatment

7 Potential immunotherapeutic effect of heated milk and egg Lemon-Mule H. JACI 2008:122:977; Nowak-Wegrzyn A. JACI 2008:122:342; Schreffler WG. JACI 2009:123:43 ~75% of allergic children tolerate extensively heated product via OFC Regulatory T cells Associated with reductions in: specific IgE PST basophil activation Treg activation

8 Methods of immunotherapy Oral IT (OIT) –swallowed with food –open and blinded studies –mg – gms of food

9 Patterns of response to food OIT Nowak-Wegrzyn JACI March 2011

10 Maintenance *Food Challenge #1 (OFC 1) Desensitization 4000 mg Initial escalation day – 6 mg 1 peanut = 300 mg Varshney et al. JACI March 2011 Dose Escalation Peanut or Placebo Study design: double-blind RCT peanut OIT Duke and Arkansas

11 Maintenance *Food Challenge #1 (OFC 1) Food Challenge #2 (OFC 2) Food Challenge #3 (OFC 3) Desensitization Tolerance Meet criteria for assessing tolerance 4000 mg 1 mo Initial escalation day – 6 mg 1 peanut = 300 mg Off OIT Varshney et al. JACI March 2011 Dose Escalation Peanut or Placebo Study design: double-blind RCT peanut OIT Duke and Arkansas

12 Peanut OIT induces robust clinical desensitization and suppresses mast call activation 25 subjects – 16 - active treatment; 9 – placebo (3 withdrew) Any peanut-allergic subject – unless accompanied by significant hypotension All subjects - maximum dose of 6 mg (initial day); 4000 mg during build-up P=.008 * Varshney et al. JACI March 2011 Peanut OFC 1

13 Peanut OIT induces robust clinical desensitization and suppresses mast call activation 25 subjects – 16 - active treatment; 9 – placebo (3 withdrew) Any peanut-allergic subject – unless accompanied by significant hypotension All subjects - maximum dose of 6 mg (initial day); 4000 mg during build-up P=.008 * Varshney et al. JACI March 2011 Peanut SPT Peanut OFC 1

14 Peanut antigen specific suppression Basophils – CD63% Hi Thyagarajan, Shreffler et al. AAAAI 2009 Significant change in basophils – CD63% over time on OIT 4 concentrations of peanut cultured with subject’s cells at each time point – 0, 6 and 12 months ( PN1, PN2, PN3, PN4)

15 ImmunoCAP-FEIA (Phadia) Serum levels of peanut-specific IgE and IgG4 changes with OIT treatment Varshney et al. JACI March 2011 Peanut IgE

16 ImmunoCAP-FEIA (Phadia) Serum levels of peanut-specific IgE and IgG4 changes with OIT treatment Varshney et al. JACI March 2011 Peanut IgEPeanut IgG4

17 Possible Mechanism(s) of OIT? Peanut-allergic subjects on peanut OIT show a decrease in basophil responses to ex vivo peanut stimulation during the course of treatment. Plasma - peanut-allergic subjects (n=10, median peanut-specific IgE 82.3 kU/L) and replaced with plasma from subjects receiving peanut (n=7) or placebo (n=5) OIT. Basophil activation was assessed by measuring up-regulation of CD63. Plasma samples from 0 and 12 months on OIT were used. Peanut-allergic donor samples receiving plasma from subjects on peanut OIT for 12 months showed a significant decrease in basophil activation when compared to samples receiving plasma from subjects on peanut OIT for 0 months (n=28, p<0.0001) and when compared to samples receiving plasma from subjects on placebo OIT for 12 months (n=21, p<0.0001). Basophil activation between samples receiving plasma from 0 and 12 months on placebo OIT (n=21) was not significantly different. Kulis et al. 2011

18 Possible Mechanism(s) of OIT? For the transferred plasma, there was an increase in peanut-specific IgG between 0 and 12 months on peanut OIT (median increase 18 mg/L to 108 mg/L; p<0.01), and no increase for placebo. Conclusions - a factor in the plasma of subjects on peanut OIT suppressed ex vivo basophil activation in peanut-allergic subject. Our hypothesis is that the factor is peanut-specific IgG, although further studies are needed to definitively identify it and determine its mechanism of action. Kulis et al 2011

19 Permanent tolerance develops in some after 3 years of OIT Duke and Arkansas 27 subjects -On OIT >36 months -Open study design 13/27 (48%) passed food challenges to peanuts Off treatment These subjects remain off OIT and ingest peanut in their diets Varshney, Jones, Burks et al. AAAAI 2010

20 Peanut OIT changes antigen-specific T regs and suppresses the T H 2 response to peanut IL-5 IL-13 Regulatory T cells, active treatment Varshney et al. JACI March 2011 Kulis AAAAI 2011 IL10/IL-13 ratio

21 Peanut OIT open trial - >36 Months Lower peanut IgE levels on entry are associated with successful completion

22 CoFAR3 - egg OIT trial Objectives and study design Primary Objectives –study the clinical effects, as well as the safety and immunologic effects, of an egg OIT protocol Primary endpoint is attainment of clinical tolerance after 2 years OIT Study Design –multi-center randomized, double-blind, placebo-controlled, prospective study through weeks Enrollment criteria (target n=55) –Age 6 to 18 yrs, either sex, any race, any ethnicity with: - convincing clinical history of egg allergy - serum IgE [UniCAP TM ] to egg of >5 kUA/L [<12 mo]; OR –Age 5 yrs, either sex, any race, any ethnicity with: - convincing clinical history of egg allergy - serum IgE [UniCAP TM ] to egg of >12 kUA/L [<12 mo] Supported by NIH-NIAID U19AI and U0AI066560

23 CoFAR3 egg OIT – permanent tolerance develops after 2 years of OIT Jones, Burks, Sampson et al CoFAR AAAAI 2011 PlaceboEgg OIT 5 gm desensitization OFC (10 Month)* 0/15 (0%)22/40 (55%) 10 gm desensitization OFC (22 Month)* 0/15 (0%) (n=1) 30/40 (75%) (n=34) 10 gm tolerance OFC (23 Month)** 0/15 (0%) (n=0) 11/40 (27.5%) (n=29) Predictors of tolerance = change in PST baseline to yr 2 (-10.5 OIT vs placebo)

24 Safety of food OIT Risk factors for unanticipated reactions: –Fever, viral infections, exercise, menses (Varshney JACI 2009) Symptoms occur with ~15-25% of doses –Predominantly mild and oropharyngeal –<1% of doses – moderate-severe symptoms Epinephrine use –<1% of doses Gastrointestinal symptoms are early and limiting Drop-out rate ~10-20%

25 Early intervention? Oral Immunotherapy Dr. Brian Vickery - Clinical trial to test the hypothesis that early intervention (EI) improves the efficacy of peanut OIT without adversely affecting safety or adherence. 40 peanut-sensitized children - aged 9-36 months were enrolled within six months of their initial reaction, or if the peanut-specific IgE (psIgE) exceeded 5 kU A /L in the absence of exposure. All subjects underwent baseline oral peanut challenge and were randomized to receive low- or high-dose OIT. Compared demographic, safety, adherence, and immunologic data between the EI cohort and an ongoing, previously reported trial of OIT in older children (PMIT).

26 Early intervention? Oral Immunotherapy Subjects were approximately half as likely as PMIT subjects to have an allergic side effect (ASE) deemed “likely” or “possibly” related to OIT [RR 0.56 (95%CI ), p<0.0001]. Study termination due to ASE occurred in 3/26 (11.5%) PMIT compared to 1/40 (2.5%) EI [p=0.29]. After one year, peanut skin test size decreased similarly in both groups, and psIgE levels remained stable. Conclusions - early intervention with OIT may enhance safety and targets young peanut-allergic children for treatment while their psIgE levels are low.

27 Variables in OIT studies to date Food Maintenance Dose Length TherapyOn-Therapy Food Challenge (median dose) Number of Patients Skripak et al, 2008Milk500 mg milk protein daily 13 weeks5140 mg ( ) 13 Narisety et al, 2009Milk1,000 to 16,000 mg milk protein 13 to 75 weeks (after original 13 weeks) 6 tolerated 16,000 mg with no reaction; 7 reacted at 3,000 to 16,000 mg 13 Jones et al, 2009Peanut300 mg peanut protein daily 16 to 22 months27 reached 3.9 g peanut. Median dose at first symptom was 1800 mg ( ) 29 Clark et al, 2009Peanut800 mg peanut protein daily 6 weeks maintenance Subjects tolerated 2.38 g protein to 2.76 g without reaction 4 Varshney et al, 2011 Peanut4000 mg peanut protein monthsAll 16 tolerated 5000 mg 16 Morisset et al, 2007 EggRoutine amounts6 months34/49 consumed 7 g egg white without symptoms 49 Buchanan et al, 2007 Egg300 mg powdered egg white 24 months8000 mg powdered egg white ( ) 7 Jones et al, 2011Egg2000 mg powdered egg white 10 months5000 mg ( ) 40

28 Patriarca et al. Aliment Pharmacol Ther 2003;17: Meglio P, et al.. Allergy 2004;59: Buchanan AD et al. J Allergy Clin Immunol 2007;119: Staden U, et al. Allergy 2007;62: Longo G, et al. J Allergy Clin Immunol 2008;121: Jones SM, et al. J Allergy Clin Immun Skripak JM et al. J Allergy Clin Immunol 2008;122: Blumchen K et al. J Allergy Clin Immunol 2010;126: Varshney P et al. J Allergy Clin Immunol March 2011 (In Press). Jones SJ, Burks AW, Sampson HA et al – CoFAR 2011 Summary - consistent results 1. Desensitization begins within a few days/months of treatment – threshold goes up 2. Allergic side effects - primarily GI at the beginning - viral infections, exercise 3. Mechanistic studies – results differ depending on length of study 4. Tolerance not shown in blinded studies Critical knowledge gaps in food OIT research

29 SPT mean wheal size decreased by 6 mo Further decreased to 24 mo Basophil activation decreased by 4 mo Further decreased to 24 mo Effector Cells Specific-IgE increased by 2-3 mo Between 6-18 mo – variable, similar to baseline or decreased. By 24 mo is decreased Specific-IgE Specific-IgG4 increased by 2-3 mo Continues to increase to 24 mo, then begins to decline Specific-IgG4 Time on OIT (months)

30 Immunotherapy for food allergy – the future ? Goal: development of initial active treatment for food allergy OIT/SLIT – still investigational –Studies needed to understand possible clinical benefit and mechanism randomized, blinded controlled trials – in process now optimizing pharmacokinetics targeting appropriate population(s) Determine mechanism of action of OIT/SLIT –Basophils/mast cells, humoral, cellular Determine if food IT induces –Desensitization without/and clinical tolerance –Is desensitization alone worthwhile? Longer term goal: next-generation of therapy to enhance the development of immune tolerance

31 Thanks Grant support Food Allergy and Anaphylaxis Network, Food Allergy Project, Food Allergy Initiative, Gerber Foundation, NIHR01 – AI, NIHR01-NCCAM, NIH 1 UL1 RR (DCRU), Doris and Frank Robins Family, National Peanut Board, NIAID-CoFAR Team Physicians - Stacie Jones (AR), Joe Roberts, Brian Vickery, Michael Land, Wayne Shreffler (Harvard), Hugh Sampson (Mt. Sinai), CoFAR Team Study coordinators - Pam Steele, Jan Kamilaris, Alison Edie, Janie Hainline Fellows - Amy Scurlock, Arianna Buchanan, Krisha Palmer, Todd Green, Alison Hofmann, Pooja Varshney, Ananth Thyagarajan, Drew Bird, Edwin Kim, Stacy Chin, Stephen Boden Laboratory - Mike Kulis, PhD, Xiaoping Zhong, MD/PhD, Laurent Pons, PhD, Herman Staats, PhD DCRU/Rankin staff


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