New pill could quiet chronic cough in adults
NCT ID NCT05660850
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study tested an experimental drug called GDC-6599 in 49 adults with chronic cough that persists despite treatment for asthma, COPD, or for unknown reasons. Participants took the drug or a placebo for two weeks, then switched. The goal was to see if the drug reduces cough frequency and severity. Results are not yet available.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- GDC-6599 (an experimental oral drug)
- What this could lead to
- If successful, this could lead to a new treatment option for people with chronic cough that doesn't respond to other therapies.
- What could go wrong
- This is a small, early-phase trial with only 49 participants. The drug may not work better than placebo, and side effects are still being studied.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 2
Tests whether the treatment actually works, and watches for side effects, in a larger group.
- Participants
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49 people
The number who actually took part.
- Started
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Mar 2023
- Finished
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Oct 2024
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 to 80 years
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: * Previous diagnosis of CRC, despite optimized treatment for asthma or COPD, or UCC for at least 1 year * Chest X-ray or computed tomography (CT) scan thorax within 5 years prior to screening visit that confirms the absence of any clinically significant abnormality contributing to the chronic cough in the opinion of the investigator * Cough severity VAS score ≥ 40 at screening visit * Pre-bronchodilator forced expiratory volume in 1 second (FEV1) ≥ 60% of predicted at screening" * Mannitol CDR ≥ 12 coughs/100 mg determined at screening visit mannitol challenge test * For women of childbearing potential: agreement to remain abstinent or use contraception For men: agreement to remain abstinent or use a condom, and agreement to refrain from donating sperm Inclusion Criteria for Patients with CRC with Atopic Asthma or Patients with CRC with Non-Atopic Asthma (Part A) * Physician diagnosis of asthma for ≥ 12 months based upon GINA STEP 2-5 * Stable treatment with ICS therapy (GINA STEP 2) or ICS therapy and at least one additional controller (GINA STEP 3- 5) for ≥ 3 months * Patients with atopic asthma (n = 20), based upon historic record of positive test for atopy (if available), or confirmed at screening by positive fluorescence enzyme immunoassay for specific IgE against at least one of the following five perennial aeroallergens: animal (cat dander, dog dander, cockroach), dust mite (Dermatophagoides farinae, Dermatophagoides pteronyssinus), and mold mix * Patients with non-atopic asthma (n = 20), based upon historic record of negative test for atopy (if available), or confirmed at screening by negative ImmunoCAP test result for all five perennial aeroallergens: animal (cat dander, dog dander, cockroach), dust mite (Dermatophagoides farinae, Dermatophagoides pteronyssinus), and mold mix, and relevant local allergens, and no history of symptoms suggesting atopy * Never or former smoker (≥ 6 months prior to screening) with \< 20 pack-years or equivalent history Inclusion Criteria for Patients with CRC COPD-CB or Patients with CRC COPD (Part B) * Diagnosis of COPD GOLD I-II ± CB * Stable background treatment consisting of a bronchodilator medication and or stable ICS therapy for ≥ 12 weeks prior to screening visit * Former smoker with ≥ 10 pack-years or equivalent history within 6 months of screening * Post-bronchodilator FEV1/ forced vital capacity (FVC) ratio ≤ 0.70 at screening * Chest X-ray or CT scan within 6 months prior to screening visit or during the screening period (prior to randomization \[Study Visit 2\]), that confirms the absence of clinically significant lung disease besides COPD Exclusion Criteria: * Pregnant or breastfeeding, or intention of becoming pregnant during the study or within 28 days after the final dose of GDC-6599 * History of diagnosed bleeding diathesis or easy bruising or bleeding * Post-bronchodilator FEV1/ FVC ratio \< 0.60 at screening visit (patients with CRC asthma and UCC only: Part A) * History of significant hepatic impairment * History of aspiration or recurrent pneumonia * Respiratory infection (including upper respiratory infection) within 8 weeks prior to screening * Treatment with any strong inhibitor or inducer of CYP3A within 28 days or 5 drug-elimination half-lives, whichever is longer, prior to initiation of study drug * Treatment with angiotensin-converting enzyme (ACE) inhibitor within 12 weeks prior to screening (Study Visit 1) through completion of the study * Treatment with opioids (including codeine), pregabalin, gabapentin, amitriptyline, or nortriptyline for the treatment of cough within 2 weeks prior to screening (Study Visit 1) through completion of the study * Treatment with cough suppressant medication within 2 weeks prior to screening (Study Visit 1) through completion of the study * Known coronavirus 2019 (COVID-19) infection, persistent symptoms of known prior COVID-19 infection, and/or known positive COVID-19 test within at least 8 weeks prior to screening and randomization * Clinical laboratory value outside the reference range for the test laboratory at screening * Any serious medical condition or abnormality in clinical laboratory tests that, in the investigator's judgment, precludes the patient's safe participation in and completion of the study * History of malignancy within 5 years prior to screening, except for appropriately treated carcinoma in situ of the cervix or non-melanoma skin carcinoma
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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ADAC Research PA
Greenville, South Carolina, 29607, United States
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Belfast City Hospital
Belfast, BT9 7AB, United Kingdom
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Bellingham Asthma, Allergy & Immunology
Bellingham, Washington, 98225, United States
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California Medical Research Associates, Inc.
Northridge, California, 91324, United States
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Castle Hill Hospital
Cottingham, North Humberside, HU16 5JQ, United Kingdom
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Clinical Research Associates Of Central Pa , Llc
DuBois, Pennsylvania, 15801-2277, United States
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Diex Recherche - Québec - HyperCore - PPDS
Québec, Canada
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Glenfield Hospital
Leicester, LE3 9QP, United Kingdom
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Kings College Hospital
London, SE5 9RS, United Kingdom
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Mayo Clinic
Rochester, Minnesota, 55905, United States
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McMaster University Medical Centre
Hamilton, Ontario, L8N 3Z5, Canada
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Pharmaceutical Research & Consulting, Inc.
Dallas, Texas, 75231, United States
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Pioneer Clinical Studies
Coral Gables, Florida, 33134, United States
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Queen Anne Street Medical Centre
London, W1G 8HU, United Kingdom
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Royal Infirmary of Edinburgh
Edinburgh, EH16 4SA, United Kingdom
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Southern California Institute For Respiratory
Los Angeles, California, 90048, United States
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TrialsWest Pty Ltd
Spearwood, Western Australia, 6163, Australia
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West Walk Surgery
Bristol, BS37 4AX, United Kingdom
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