The Asthma Bronchial Challenge Study

Study Overview
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Brief Summary
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This is a randomised, controlled, cross-over study to determine the effect of indirect bronchial challenge testing upon volatile organic compounds (VOCs) in the exhaled breath of adults with well-controlled, mild-to-moderate asthma. Participants will undergo baseline evaluation including clinical history, spirometry, exhaled nitric oxide measurement (FeNO), phlebotomy (blood eosinophil count), and sampling of exhaled breath VOCs. Participants will be randomised to receive either an indirect bronchial challenge test using mannitol dry powder (MDP) or a sham bronchial challenge, followed by further sampling of breath VOCs. The study will consist of a consent visit and two assessment visits with participants allocated to receive one of the two challenges (MDP or sham) at each assessment. Data will be analysed to determine the effect of bronchial challenge upon exhaled breath VOC profiles.

Official Title
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Bronchial Challenge Testing in Asthma: The Effect of Mannitol Dry Powder Inhalation on Volatile Organic Compounds in Exhaled Breath

Conditions
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Asthma

Intervention / Treatment
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* Diagnostic Test: Indirect bronchial challenge
* Other: Sham bronchial challenge


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or female Aged 18 or over Able to provide informed consent Self-report of asthma diagnosis from health professional Diagnostic confirmation meeting British Thoracic Society guidelines will be sought from primary care Non-smokers; or ex-smokers of at least two years duration with less than a ten pack year history Asthma Control Questionnaire score < 1.0 Asthma treated according to level-1 to level-2 of British Thoracic Society treatment guidelines Exclusion Criteria: Respiratory tract infection, asthma exacerbation or change in treatment step within the previous four weeks Major chronic cardiorespiratory disease other than asthma Significant comorbid condition Condition that may be compromised by repeated spirometry manoeuvres or induced bronchospasm Asthma Control Questionnaire score >1.0 Asthma treated at level 3 of the treatment guidelines or higher Pregnant or nursing mothers Current smokers or 'vapers' Ex-smokers of < 2 years duration or > 10 pack years. Participating in a clinical trial of an investigational medicinal product (CTIMP). Unable to speak English. Low baseline lung function (FEV1 <1.50 litres or < 70% predicted value) Known hypersensitivity to mannitol, gelatin or strong anaphylactic response in the past.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Diagnostic Test: Indirect bronchial challenge|Mannitol dry powder inhalation|
|Other: Sham bronchial challenge|Mock dry powder inhalation|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in exhaled breath profile | Exhaled volatile organic compounds (VOCs) will be captured on sorbent material and analysed by gas chromatography-mass spectrometry. Post-bronchial challenge samples will be compared with baseline, pre-challenge samples. Differences in exhaled VOC profile will be assessed for significance. | Immediately post-bronchial challenge | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Breathomics, Metabolomics, Exhaled breath test, Biomarker