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Oral ImmunotherapyOral Immunotherapy

Wesley Burks, M.D.Wesley Burks, M.D.Professor and ChairProfessor and Chair

Department of PediatricsDepartment of PediatricsUniversity of North CarolinaUniversity of North Carolina

FACULTY DISCLOSURE

• FINANCIAL INTERESTSI 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 Allertein Minority StockholderDannon Co. Probiotics Advisory BoardExploraMed ConsultantIntelliject ConsultantMast Cell, Inc. Minority StockholderMcNeil Nutritionals ConsultantNovartis ConsultantNutricia Expert PanelSchering-Plough Consultant

• RESEARCH INTERESTSI 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 Health GranteeFood Allergy and Anaphylaxis Network GranteeSHA GranteeFAI GranteeNational Peanut Board GranteeWallace Foundation Grantee

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Background: Food allergy

Vander Leek, J Peds 2000Bock, J Allergy Clin Immunol 2007

Food allergy and what parents hear

Nowak-Wegrzyn JACI March 2011

Approaches to food allergy immunotherapy

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

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

Methods of immunotherapy

• Oral IT (OIT) – swallowed with food

– open and blinded studies

– mg – gms of food

Patterns of response to food OIT

Nowak-Wegrzyn JACI March 2011

Maintenance

*Food Challenge #1 (OFC 1)

Desensitization

4000 mg4000 mg

Initial escalation day – 6 mg

1 peanut = 300 mg

Varshney et al. JACI March 2011

Dose EscalationPeanut or Placebo

Study design: double-blind RCT peanut OIT Duke and Arkansas

Maintenance

*Food Challenge #1 (OFC 1)

Food Challenge #2(OFC 2)

Food Challenge #3(OFC 3)

Desensitization

Tolerance

Meet criteria for assessing tolerance

4000 mg4000 mg

1 mo

Initial escalation day – 6 mg

1 peanut = 300 mg

Off OIT

Varshney et al. JACI March 2011

Dose EscalationPeanut or Placebo

Study design: double-blind RCT peanut OIT Duke and Arkansas

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

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 SPTPeanut OFC 1

Peanut antigen specific suppressionBasophils – 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)

ImmunoCAP-FEIA (Phadia)

Serum levels of peanut-specific IgE and IgG4changes with OIT treatment

Varshney et al. JACI March 2011

Peanut IgE

ImmunoCAP-FEIA (Phadia)

Serum levels of peanut-specific IgE and IgG4changes with OIT treatment

Varshney et al. JACI March 2011

Peanut IgE Peanut IgG4

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

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

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

0 mo 12 mo 24 mo1

10

100

**

*

IL-1

3 (p

g/m

l)Peanut OIT changes antigen-specific T regs and

suppresses the TH2 response to peanut

IL-5

IL-13

Regulatory T cells, active treatment

Varshney et al. JACI March 2011Kulis AAAAI 2011

IL10/IL-13 ratio

0 mo 12 mo 24 mo0

100

200

300

400

500

600

****IL

-5 (

pg

/ml)

0 mo 12 mo 24 mo0.1

1

10

100

1000

***

IL-1

0:IL

-13

rati

o

0 mo 12 mo 24 mo0

5

10

15

20

*

Tre

gs

CD

25+

Fo

xP3+

(%

of

CD

4+)

Peanut OIT open trial - >36 Months

Lower peanut IgE levels on entry are associated with successful completion

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 40-48 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 [UniCAPTM] 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 [UniCAPTM] to egg of >12 kUA/L [<12 mo]

Supported by NIH-NIAID U19AI066738 and U0AI066560

CoFAR3 egg OIT – permanent tolerance develops after 2 years of OIT

Jones, Burks, Sampson et al CoFAR AAAAI 2011

Placebo Egg 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. -5.5 placebo)

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%

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 kUA/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).

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 0.50-0.62), 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.

Variables in OIT studies to dateFood Maintenance

DoseLength Therapy On-Therapy

Food Challenge (median dose)

Number of Patients

Skripak et al, 2008 Milk 500 mg milk protein daily

13 weeks 5140 mg (2540-8140)

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Narisety et al, 2009 Milk 1,000 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

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Jones et al, 2009 Peanut 300 mg peanut protein daily

16 to 22 months 27 reached 3.9 g peanut. Median dose at first symptom was 1800 mg (300-11800)

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Clark et al, 2009 Peanut 800 mg peanut protein daily

6 weeks maintenance

Subjects tolerated 2.38 g protein to 2.76 g without reaction

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Varshney et al, 2011

Peanut 4000 mg peanut protein

11-16 months All 16 tolerated 5000 mg

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Morisset et al, 2007 Egg Routine amounts 6 months 34/49 consumed 7 g egg white without symptoms

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Buchanan et al, 2007

Egg 300 mg powdered egg white

24 months 8000 mg powdered egg white (2000-8000)

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Jones et al, 2011 Egg 2000 mg powdered egg white

10 months 5000 mg (250-5000)

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•Patriarca et al. Aliment Pharmacol Ther 2003;17:459-65.•Meglio P, et al.. Allergy 2004;59:980-7.•Buchanan AD et al. J Allergy Clin Immunol 2007;119:199-205.•Staden U, et al. Allergy 2007;62:1261-9.•Longo G, et al. J Allergy Clin Immunol 2008;121:343-7.•Jones SM, et al. J Allergy Clin Immun 2009.•Skripak JM et al. J Allergy Clin Immunol 2008;122:1154-60.•Blumchen K et al. J Allergy Clin Immunol 2010;126:83-91. •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

0 2 3 4 6 9 12 18 24 36

SPT mean wheal size decreased by 6 moFurther decreased to 24 mo

Basophil activation decreased by 4 moFurther decreased to 24 mo

Effector Cells

Specific-IgE increased by 2-3 moBetween 6-18 mo – variable, similar to

baseline or decreased.By 24 mo is decreased

Specific-IgE

Specific-IgG4 increased by 2-3 moContinues to increase to 24 mo, then

begins to decline

Specific-IgG4

Time on OIT (months)

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

ThanksGrant support

Food Allergy and Anaphylaxis Network, Food Allergy Project, Food Allergy Initiative, Gerber Foundation, NIHR01 – AI, NIHR01-NCCAM, NIH 1 UL1 RR024128-01 (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