ToAST:Investigating the Effect of Bronchial Thermoplasty on Cough in Patients With Severe Asthma

National Health Service, United Kingdom

Status

Unknown

Conditions

Asthma Chronic, Cough

Treatments

Other: Inhaled capsaicin cough challenge

Study type

Interventional

Funder types

Other

Identifiers

NCT03281941

NHSUK

Details and patient eligibility

About

ToAST study is a pilot study aiming to establish the safety profile of using inhaled capsaicin challenge in patients with severe asthma. The investigators will also explore the differences in cough symptoms and threshold in patients with and without bronchial thermoplasty.

Full description

ToAST is designed as a two-visit observational study. During visit 1, written consent and measurements of baseline asthma characteristics were completed; history and examination, questionnaires (Asthma Control Questionnaires and Leicester Cough Questionnaire, and basic lung physiological assessment were performed.

At the end of visit 1, a cough monitor was attached to the subject to monitor cough frequency for the next 24 hours and this was returned at visit 2.

Visit 2 followed within two weeks after visit 1, during which a full dose capsaicin cough challenge was performed. Emergency contact details were given towards end of visit 2 should any adverse events occur.

Telephone call within 48 hours, Day 3 and Day 7: The purpose of these phone calls was to ensure that the patient had not developed any adverse effects to the capsaicin challenge.

Enrollment

24 estimated patients

Sex

All

Volunteers

No Healthy Volunteers

Inclusion criteria

Aged ≥18
Person with an established diagnosis of severe asthma
All patients should be on British Thoracic Society (BTS) steps 4 or 5
Patients who have had bronchial thermoplasty (BT) should be at least 2 months after their treatment
Historical evidence of one of the following:
Airway reversibility to a short acting beta-2 agonist of ≥12%
Bronchial hyper-responsiveness (PC20<8mg/ml)
Fractional exhaled nitric oxide ≥50ppb
Peak flow variability >8%
Raised serum (≥0.45) or sputum eosinophilia (>3%)
Variability in spirometry over 24 months of >20%

Exclusion criteria

Unable to give informed consent
FEV1<50% predicted or < 1 litre
Known allergy or intolerance to capsaicin
Symptoms of upper respiratory tract infection in the last 1 month which have not resolved.
Lower respiratory tract infection or pneumonia in the last 6 weeks.
Current smoker or ex-smoker with ≥10 pack year smoking history, abstinence of ≤6 months
Asthma exacerbation in the previous month requiring an increase or starting of an ICS or OCS
Subject has changed asthma medication within the past 4 weeks prior to screening
A previous asthma exacerbation requiring Intensive Care Unit (ICU) admission.
Significant other pulmonary disorders as the major diagnosis, in particular: pulmonary embolism, pulmonary hypertension, interstitial lung disease, lung cancer, cystic fibrosis, emphysema or bronchiectasis.
Evidence of vocal cord dysfunction
Pregnancy or breast-feeding
Use of ACE inhibitors
Any centrally acting medication which in the view of the investigator could alter the sensitivity of the cough reflex*
History of psychiatric illness, drug or alcohol abuse which may interfere in the participation of the trial.