Can We Prevent Asthma?Can We Prevent Asthma?

Fernando D. Martinez, M.D.Fernando D. Martinez, M.D.Arizona Respiratory CenterArizona Respiratory CenterThe University of ArizonaThe University of Arizona

What Do We Mean by Prevention?

What Do We Mean by Prevention?

�� A strategy for A strategy for primary preventionprimary prevention is one that, is one that, acting before the disease process ever starts, acting before the disease process ever starts, blocks its inceptionblocks its inception

�� Primary prevention requires knowledge about Primary prevention requires knowledge about the basic mechanisms that cause the diseasethe basic mechanisms that cause the disease

�� A strategy of A strategy of secondary preventionsecondary prevention, acting at , acting at the first phases of the disease process, blocks the first phases of the disease process, blocks and/or reverses its progressionand/or reverses its progression

Hypothetical Representation of the Natural History of Asthma

Initial Phase of AsthmaInitial Phase of Asthma

InceptionInception

TriggersTriggers

Progression

Progression

No AsthmaNo Asthma

PersistentPersistentAsthmaAsthma

IntermittentIntermittentAsthmaAsthma

No AsthmaNo Asthma

ProtectionProtection

Remission

Remission

Allergen ExposureAllergen Exposure

Genetic PredispositionGenetic Predispositionto Allergiesto Allergies

SensitizationSensitization

Genetic PredispositionGenetic Predispositionto Asthmato Asthma

AsthmaAsthma

Allergy,Allergy,No AsthmaNo Asthma

Exposure to Dust Mites and AsthmaExposure to Dust Mites and AsthmaExposure to Dust Mites and Asthma

�� Lau and coworkers assessed concentrations of dust Lau and coworkers assessed concentrations of dust mites allergens in the homes of >900 children during mites allergens in the homes of >900 children during the first year of lifethe first year of life

�� They subsequently followed exposed children and They subsequently followed exposed children and assessed allergic sensitization to mites and incidence assessed allergic sensitization to mites and incidence of asthma up to age 7of asthma up to age 7

Lau et al, Lancet 2000, 356:1392Lau et al, Lancet 2000, 356:1392

Lau et al, Lancet 2000, 356:1392Lau et al, Lancet 2000, 356:1392

Asthma Symptoms by Asthma Symptoms by House Dust Mite Sensitization House Dust Mite Sensitization

Asthma and BHR by Type of SensitizationAsthma and BHR by Type of Sensitization

IlliIlli et al, JACI 2001; 108:709et al, JACI 2001; 108:709

Lau et al, Lancet 2000, 356:1392Lau et al, Lancet 2000, 356:1392

Asthma Symptoms and Asthma Symptoms and HDM Sensitization by ExposureHDM Sensitization by Exposure

The Childhood Asthma PreventionStudy (CAPS), Sidney Australia

The Childhood Asthma PreventionStudy (CAPS), Sidney Australia

�� Established in 1997Established in 1997

�� Primary aims were to test whether in children at high Primary aims were to test whether in children at high risk of allergic disease the incidence of allergy and risk of allergic disease the incidence of allergy and asthma at age 5 years could be reduced by the asthma at age 5 years could be reduced by the implementation of interventions directed at avoidance implementation of interventions directed at avoidance of HDM allergens, diet supplementation with omegaof HDM allergens, diet supplementation with omega--3 3 fatty acids, or a combination of these 2 interventionsfatty acids, or a combination of these 2 interventions

MihrshahiMihrshahi et al, JACI et al, JACI 2003;111:162-8

Mihrshahi et al, JACI 2003;111:162-8

Effectiveness of the Mite Avoidance Intervention

Effectiveness of the Mite Avoidance Intervention

Outcomes at Age 5 YearsOutcomes at Age 5 Years

Marks et al,JACI 2006;118:53-61.

Conclusions: Primary PreventionConclusions: Primary Prevention

�� Two randomized mite avoidance trials (Sydney and Two randomized mite avoidance trials (Sydney and Manchester) showed no beneficial effect on asthmaManchester) showed no beneficial effect on asthma--related outcomes measured in the early school yearsrelated outcomes measured in the early school years

�� These results question the hypothesis that exposure to These results question the hypothesis that exposure to allergens causes the type of chronic asthma allergens causes the type of chronic asthma associated with early life sensitization associated with early life sensitization

Hypothetical Representation of the Natural History of Asthma

Initial Phase of AsthmaInitial Phase of Asthma

InceptionInception

TriggersTriggers

Progression

Progression

No AsthmaNo Asthma

PersistentPersistentAsthmaAsthma

IntermittentIntermittentAsthmaAsthma

No AsthmaNo Asthma

ProtectionProtection

Remission

Remission

Hypothetical Representation of the Natural History of Asthma

Asthma Initial PhaseAsthma Initial Phase

InceptionInception

ExacerbationExacerbation

Progression

Progression

No AsthmaNo Asthma

ChronicChronicAsthmaAsthma

Asthma,Asthma,Not ChronicNot Chronic

No AsthmaNo Asthma

ProtectionProtection

Remission

Remission

ICS?ICS?

CAMP Study DesignCAMP Study Design

�� Children with Children with ““mild to moderate asthmamild to moderate asthma”” (symptoms or use (symptoms or use of Albuterol of Albuterol ≥≥2 times weekly or daily use of asthma 2 times weekly or daily use of asthma medication)medication)

�� Treated for 4Treated for 4--6 years with 6 years with BudesonideBudesonide 200 200 µµg bid (N=311) g bid (N=311) or or NedocromilNedocromil 8 mg bid (N=312) or matching placebo8 mg bid (N=312) or matching placebo

�� Primary outcome: mean change % predicted post Primary outcome: mean change % predicted post bronchodilator FEV1 4bronchodilator FEV1 4--6 years after initiation of treatment6 years after initiation of treatment

N Engl J Med 2000;343:1054-63

Lung Function in the CAMP StudyLung Function in the CAMP Study

N Engl J Med 2000;343:1054-63

What Is The PEAK Trial?

PEAK is investigating if inhaled corticosteroids (ICS),

when initiated in preschool-aged children at high risk for asthma,

can alter the natural history of asthma after ICS are

discontinued

Childhood Asthma Research andEducation Network (CARE)

Clinical CentersDenver:National Jewish Medical& Research CenterMadison:University of Wisconsin

San Diego: University of CaliforniaKaiser Permanente CaliforniaSt. Louis:Washington University

Tucson:University of Arizona

Data Coordinating CenterHershey: Penn State UniversityNIH Funding Agency

Bethesda, MD:NHLBI

RationaleRationale�� Asthma Predictive Index identifies highAsthma Predictive Index identifies high--risk risk

children that will have continuation of asthmachildren that will have continuation of asthma--like symptoms in school yearslike symptoms in school years11..

�� ICS have been reported to reduce symptoms in ICS have been reported to reduce symptoms in highhigh--risk young children with intermittent risk young children with intermittent wheezingwheezing2,32,3..

�� No effect after discontinuation of ICS on the No effect after discontinuation of ICS on the natural course of asthma in school aged natural course of asthma in school aged children may be due to the initiation of ICS children may be due to the initiation of ICS after the occurrence of critical injurious after the occurrence of critical injurious eventsevents44..

1Castro-Rodriguez, AJRCCM, 2000 3Bisgaard, AJRCCM, 19992Teper, Ped Pulm, 2004 4CAMP Research Group, NEJM, 2000

• Randomized, multicenter, double-blind, parallelgroup, placebo-controlled trial

• 285 two and three year olds at high-risk for asthma• Fluticasone 44 µµµµg/puff or placebo (2 puffs b.i.d.)

Year 3Year 3

Screening/Screening/Eligibility Eligibility RunRun--inin

Interim Efficacy Tests

PEAK: Study Design

Years 1 & 2Years 1 & 21 month1 month

Randomize

Treatment Treatment Observation Observation

GuilbertGuilbert et al, NEJM 354:19; 2006 et al, NEJM 354:19; 2006

Inclusion CriteriaInclusion Criteria

�� Children 24Children 24--47 months of age47 months of age�� Positive asthma predictive indexPositive asthma predictive index�� At least 36 weeks at birthAt least 36 weeks at birth�� No systemic illnesses apart from asthma No systemic illnesses apart from asthma

or allergic rhinitisor allergic rhinitis�� >> 10% for height10% for height�� < 4 months of inhaled corticosteroid and < 4 months of inhaled corticosteroid and

< 4 courses of systemic steroid in last < 4 courses of systemic steroid in last yearyear

Asthma Predictive Index

�� Identify high risk children (ages 2 & 3): Identify high risk children (ages 2 & 3): �� >> 4 wheezing episodes in the past year 4 wheezing episodes in the past year

(at least one must be MD diagnosed)(at least one must be MD diagnosed)PLUSPLUS

�� One major criteriaOne major criteria OR OR -- Two minor criteriaTwo minor criteria�� Parent with asthmaParent with asthma •••••••• Food sensitivityFood sensitivity�� Atopic dermatitisAtopic dermatitis •••••••• Peripheral Peripheral eosinophiliaeosinophilia ((≥≥≥≥≥≥≥≥4%) 4%) �� AeroAero--allergen sensitivityallergen sensitivity •••••••• Wheezing not related to Wheezing not related to

infectioninfection

Modified from: Castro-Rodriguez, AJRRCM, 2000

�� EpisodeEpisode--free days during the free days during the observationobservation--yearyear��No cough or wheezeNo cough or wheeze��No unscheduled clinic, urgent care, No unscheduled clinic, urgent care,

ER or hospital visitsER or hospital visits��No use of asthma medications No use of asthma medications

including bronchodilator including bronchodilator prepre--treatment before exercisetreatment before exercise

PEAK: Primary Outcome

Addition of ControllersAddition of Controllers

Persistent Symptoms OR> 4 courses of oral steroids in 12 mos

Montelukast

Open label fluticasone

Other supplementary asthma medications

Taper after 2 months based on specific protocols

Study Population: Enrollment and Disposition

Study Population: Enrollment and Disposition

285 Randomized Participants285 Randomized Participants

143 in ICS group143 in ICS group 142 in placebo group142 in placebo group

132 132 included in included in Year 1 & 2 Year 1 & 2 analysesanalyses

131 131 included included in Year 3 in Year 3 analysisanalysis

130 130 included in included in Year 1 & 2 Year 1 & 2 analysesanalyses

125 125 included included in Year 3 in Year 3 analysisanalysis

0.75

0.80

0.85

0.90

0.95

1.00

6 12 18 24 30 36

† † †

†

ICSPlacebop<0.05p<0.01

Pro

porti

on o

f Epi

sode

-free

Day

s

Months

Episode-free Days During the Entire Study

Treatment Treatment Observation Observation

0

20

40

60

80

100

Number per 100 child

yearsPlaceboICS

ICS Effect During Treatment Phase

P<0.001

Asthma Exacerbations

ICS Effect During Treatment Phase

0

7

14

21

28

ICS Montelukast

Days per year

Placebo

ICS

P<0.001 P<0.001

Supplementary Controller Use

ICS Effect on IOS Measures:Reactance at 5 Hz

ICS Effect on IOS Measures:Reactance at 5 Hz

-0.45

-0.42

-0.39

-0.36

-0.33

End oftreatment

End ofobservation

PlaceboICS

p=0.008 p=0.83

�� Average height Average height percentile: percentile:

�� End of Treatment: End of Treatment: ICS: 51.5%ile ICS: 51.5%ile

versus versus Placebo: 56.4%ile Placebo: 56.4%ile

(p = 0.0001)(p = 0.0001)

�� End of observation:End of observation:ICS: 54.4%ileICS: 54.4%ile

versus versus Placebo: 56.4%ile Placebo: 56.4%ile

(p=0.03) (p=0.03)

Low Dose ICS Impacted Growth

Months

Gro

wth

sin

ce b

asel

ine

(cm

)

0

5

10

15

20

0 8 16 24 30 36

PlaceboICSp<0.01

ConclusionsConclusions

�� Daily ICS are effective in preventing Daily ICS are effective in preventing exacerbations and controlling symptoms in 2exacerbations and controlling symptoms in 2--3 yr olds at high risk for asthma3 yr olds at high risk for asthma

�� However, two years of treatment with daily However, two years of treatment with daily ICS did not change the natural history of ICS did not change the natural history of asthma in these same children asthma in these same children

�� These findings question a central role of ICSThese findings question a central role of ICS--sensitive inflammation in the persistence and sensitive inflammation in the persistence and progression of asthmaprogression of asthma