Mechanisms of Change in Behavioral Cough Suppression Therapy for Refractory Chronic Cough

Recruiting now · Phase 2

Conditions studied: Chronic Cough (CC), Refractory Chronic Cough, Unexplained Chronic Cough

In brief

This study is testing new ways to help people who have chronic cough that has not improved with typical treatments. One approach is called behavioral cough suppression (BCS) therapy, which teaches people techniques to stop themselves from coughing. Another approach uses a natural substance thought to help reduce the body's sensitivity to cough triggers. In this study, we will test two treatments and include one no-treatment control group. The control group will undergo baseline testing, cough monitoring, and an fMRI brain scan and will be offered BCS at end of study participation. The two treatments include: * BCS therapy with active inhaled treatment (BCS+active), * BCS therapy with inactive inhaled treatment (BCS+inactive), The investigators will enroll 135 adults with refractory chronic cough (RCC). 100 participants who qualify and are willing and able to complete 14 study visits in the clinic and two online study visits will be randomly assigned to one of the two treatments. The no-treatment control group (n=35) will be recruited from adults with RCC who are willing to complete baseline testing and fMRI but are not able or willing to attend 14 study clinic visits. These participants will not be randomized. The investigators want to find out how these treatments affect: * How sensitive someone is to things that make them cough, * How well they can hold back a cough when they try, * How their brain responds to things that cause an urge-to-cough, * And how much their coughing affects their quality of life. The investigators believe both treatments will reduce sensitivity to cough stimulants, reduce cough severity, and improve quality of life, but BCS+active inhaled treatment will work better than BCS+inactive inhaled treatment.

Key facts

Study ID: NCT06960759
Run by: University of Montana
People needed: 135
Starts: 2026-08-15
Expected to finish: 2030-03-31
Last updated by the study team: 2026-08-04

Who can join

Age: 18 and older, up to 99. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

To be eligible to participate, participants must meet the following criteria:
18 - 99 years of age
Diagnosis of refractory or unexplained chronic cough
Normal chest imaging (x-ray or CT scan) within past 2 years, without change in cough symptoms
If you a potential participant has asthma, the following criteria must be met:
Asthma diagnosed by a pulmonary provider
Documentation from a pulmonary provider that asthma is well-controlled
Agree to carry prescribed rescue inhaler to each study visit
Can tolerate, and agree to, avoid rescue inhaler use for 4 hours prior to each study visit. If rescue inhaler use is unavoidable within 4 hours of a study visit, agree to inform researchers in advance so that the session can be rescheduled.
Normal pulmonary function testing with spirometry (FEV1/FVC of at least 70% if diagnosed with asthma) within 2 years (6 months for those with a diagnosis of asthma), without change in symptoms since (NOTE: spirometry is included as part of cough threshold testing and can serve as this criteria if the participant has not had spirometry within the designated time.)
Laryngoscopy or stroboscopy within 2 years without evidence of structural pathology and no change in vocal quality since exam
Proficient reader/speaker of English
Willing to take a pregnancy test before enrollment (if applicable)
Willing to use contraception during the study (if applicable)
Access to reliable internet, working email address (for surveys) and a smart phone (for use with CoughMonitor Watch)
Demonstrates understanding in study procedures and risks in order to consent
Available, and willing, to comply to all study procedures and clinic visits.

You may not qualify if…

Any of the following will be grounds for exclusion from the study:
Currently a smoker of any substance or has a positive history of smoking any substance within the last 6 months
Currently suffering from any signs of an upper respiratory infection (other than cough)
Hemoptysis (coughing up blood) within the last 6 months
Pulmonary diagnosis other than asthma
Asthma criteria - participant is deemed ineligible if screened for one or more of the following:
Use of rescue inhaler in response to active asthma symptoms ≥ 2 times per week
Respiratory related emergency department visit within the past 4 weeks
Respiratory related ICU admission within the past 12 months
Asthma exacerbation requiring systemic corticosteroid use within the past 4 weeks
Pregnant or trying to become pregnant
Any complaints or clinical symptoms of dysphagia
Live with someone with chronic cough or work with someone with chronic cough who is in close proximity (e.g., within 25 feet) on a daily or nearly daily basis
Known allergy to peppers
Currently receiving or has received BCS therapy for management of refractory chronic cough
Excluded concomitant medications:
Inhaled pulmonary medications (inhaled corticosteroids, short-acting beta agonists, long-acting beta-agonist, short-acting muscarinic antagonists), unless prescribed for asthma by pulmonary provider: 30 days prior to Visit 1 through completion of study participation
ACE inhibitor (benazepril, captopril, enalapril, fosiniopril, lisinopril, perindopril, quinapril, ramipril, trandolapril): 30 days prior to Visit 1 through completion of study participation.
Narcotic antitussive (hydrocodone, oxycodone, morphine, codeine, tramadol): 7 days prior to Visit 1 through completion of study participation
Non-narcotic antitussive (benzonatate/Tessalon, dextromethorphan/Delsym, carbetapentane/Solotuss): 7 days prior to Visit 1 through completion of study
P2X3 receptor antagonist (gefapixant/Lyfnua): 14 days prior to Visit 1 through completion of study
Any off-label prescription medication prescribed for cough (pregabalin/Lyrica, gabapentin/Neurontin, amitriptyline/Elavil): 14 days prior to Visit 1 through completion of study *if a neuromodulator is prescribed for something other than cough, participant must be on a stable dose for a minimum of 7 days
The following additional exclusion criteria will apply to participants who will undergo fMRI:
Presence of metal implants, devices or fragments (e.g., shrapnel) in the body
Claustrophobia

Where it is running

Emory University — Atlanta, Georgia, United States (enrolling)
University of Montana — Missoula, Montana, United States (enrolling)
University of Colorado Anschutz Medical Campus — Aurora, Colorado, United States

Full record on ClinicalTrials.gov

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