Effect of Clopidogrel on Allergen Challenge in Asthma

Study Overview
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Brief Summary
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In asthma, breathing in an allergen, such as house dust mite induces inflammation in the airways. This process appears to involve an interaction between two different sorts of blood cells, platelets and white blood cells via a receptor called the P2Y12 receptor. The purpose of this study is to determine whether the drug clopidogrel which blocks the P2Y12 receptor on platelets, reduces inflammation following breathing in house dust mite in people with mild asthma.

Official Title
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Effect of Clopidogrel on Allergen Challenge in Asthma

Conditions
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Asthma

Intervention / Treatment
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* Drug: Clopidogrel
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Confirmed diagnosis of asthma Step one of treatment by GINA (2006) guidelines baseline FEV1 >80% predicted Exclusion Criteria: current smoker ex smoker who quit <1 year prior to study and pack history >10 pack years current use of aspirin or other anticoagulant medication Diagnosis or documented history of bronchopulmonary aspergillosis or uncontrolled infections Any clinically significant cardiopulmonary abnormalities not related to pre-existing asthma Past or present tuberculosis, systemic lupus erythematosis or multiple sclerosis Any clinically significant neurological, renal, endocrine, gastrointestinal, hepatic or haematological abnormalities uncontrolled with standard treatment History of psychiatric, medical or surgical disorders that may interfere with study Clinical history suggestive of respiratory infection in month preceding study Alcohol or recreational drug abuse Diagnosis of immunodeficiency requiring treatment Treatment with immunomodulators (inhaled corticosteroids in two months or oral corticosteroids in six months prior to study) Ongoing allergen desensitisation therapy Regular use of sedatives, hypnotics, tranquillisers Positive hepatitis viral antigens or antibodies Blood donation within 3 months of the study Live immunisation <4 wks prior to study Inability to understand directions for study assessment Inability to be contacted in case of emergency Participation in another study at the same time or within a prior 3-month period

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Placebo<br>Arm given placebo | Drug: Placebo<br>* Matched placebo<br>|
| Experimental: Clopidogrel<br>Group given clopidogrel | Drug: Clopidogrel<br>* Clopidogrel 75mg daily for 7 days<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in sputum eosinophils following allergen challenge in the presence and absence of clopiodgorel |  | 8 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Provoking concentration of methacholine inducing 20% fall in forced expiratory volume in 1 second |  | 8 days | 
| Change in sputum tissue factor concentration following allergen challenge in the presence and absence of clopidogrel |  | 8 days | 
| Change in sputum tissue factor inhibitor concentration following allergen challenge in the presence and absence of clopidogrel |  | 8 days | 
| Change in sputum thrombin activatable finbrinolysis inhibitor concentration following allergen challenge in the presence and absence of clopidogrel |  | 8 days | 
| Change in sputum P-selectin concentration following allergen challenge in the presence and absence of clopidogrel |  | 8 days | 
| Change in peripheral blood eosinophil and platelet counts following allergen challenge in the presence and absence of clopidogrel |  | 8 days | 
| Change in urine fibrin degradation products and leukotriene E4 following allergen challenge in the presence and absence of clopidogrel |  | 8 days |