A Study of Gefapixant (MK-7264) in Adult Participants With Chronic Cough (MK-7264-027)
Condition: Chronic Cough
MeSH terms: Cough
Intervention: Placebo; Gefapixant
Intervention description: Participants receive dose-matched placebo tablets orally BID during the 12-week main study period and during the 40-week extension period.; Gefapixant 15 mg or 45 mg tablet administered orally BID during the 12-week main study period and during the 40-week extension period, according to randomization.
Phase: Phase 3
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Participants with refractory or unexplained chronic cough will be randomized to 1 of 3 treatment groups during the Treatment Period: Placebo, gefapixant 15 mg twice daily (BID), or gefapixant 45 mg BID. Participants will remain on their assigned treatment throughout the study. A safety follow-up phone call will be conducted at a minimum of 14 days after last dose of study treatment.
Masking: Double (Participant, Investigator)
Enrollment: 732.0
Sex: All
Minimum age: 18 Years
Healthy volunteers: No

Summary:

      The main objectives of this study will be to evaluate the efficacy of gefapixant in reducing
      cough frequency as measured over a 24-hour period at Week 12, and to evaluate the safety and
      tolerability of gefapixant. The primary hypothesis is that at least one gefapixant dose is
      superior to placebo in reducing coughs per hour (over 24 hours) at Week 12.
    

Eligibility criteria:

        Inclusion Criteria:

          -  Chest radiograph or computed tomography scan of the thorax (within 5 years of
             Screening/Visit 1 and after the onset of chronic cough) not demonstrating any
             abnormality considered to be significantly contributing to the chronic cough or any
             other clinically significant lung disease in the opinion of the principal investigator
             or the sub-investigator

          -  Has had chronic cough for at least 1 year with a diagnosis of refractory chronic cough
             or unexplained chronic cough

          -  Female participants are eligible if not pregnant, not breastfeeding, and either not of
             childbearing potential, or agree to follow contraceptive guidance

          -  Provides written informed consent and is willing and able to comply with the study
             protocol (including use of the digital cough recording device and completion of study
             questionnaires)

        Exclusion Criteria:

          -  Is a current smoker or has given up smoking within 12 months of Screening

          -  Has forced expiratory volume in 1 second (FEV1)/ forced vital capacity (FVC) ratio
             <60%

          -  Has a history of respiratory tract infection or recent clinically significant change
             in pulmonary status

          -  Has a history of chronic bronchitis

          -  Is currently taking an angiotensin converting enzyme inhibitor (ACEI), or has used an
             ACEI within 3 months of Screening

          -  Has an estimated glomerular filtration rate (eGFR) <30mL/min/1.73 m^2 at Screening OR
             eGFR ≥30 mL/min/1.73 m^2 and <50 mL/min/1.73 m^2 at Screening with unstable renal
             function

          -  Has a history of malignancy <=5 years

          -  Is a user of recreational or illicit drugs or has had a recent history of drug or
             alcohol abuse or dependence

          -  Has a history of anaphylaxis or cutaneous adverse drug reaction (with or without
             systemic symptoms) to sulfonamide antibiotics or other sulfonamide-containing drugs

          -  Has systolic blood pressure >160 mm Hg or diastolic blood pressure >90 mm Hg at
             Screening

          -  Has a known allergy/sensitivity or contraindication to gefapixant

          -  Has donated or lost >=1 unit of blood within 8 weeks prior to the first dose of
             gefapixant

          -  Has previously received gefapixant or is currently participating in or has
             participated in an interventional clinical study

          -  Had significantly abnormal laboratory tests at Screening