Effect of Gefapixant (AF-219/MK-7264) on Cough Reflex Sensitivity (MK-7264-015)
Condition: Refractory Chronic Cough
MeSH terms: Cough
Intervention: Gefapixant; Placebo
Intervention description: Gefapixant tablets administered orally as a single dose of 50 mg (1 tablet) or 300 mg (6 tablets)
Phase: Phase 2
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Enrollment: 50.0
Sex: All
Minimum age: 18 Years
Maximum age: 80 Years
Healthy volunteers: Accepts Healthy Volunteers

Summary:

      The primary objective of this double-blind crossover study is to assess the effect of single
      doses of 50 mg and 300 mg gefapixant (AF-219/MK-7264) on cough reflex sensitivity to
      capsaicin in both healthy participants and participants with chronic cough. This study will
      also assess the effect of single doses of gefapixant on cough reflex sensitivity to adenosine
      triphosphate (ATP) in healthy participants and participants with chronic cough.
    

Eligibility criteria:

        Inclusion Criteria:

          -  Have provided written informed voluntary consent;

          -  Be able to speak, read, and understand English;

          -  Be males or females, of any race, between 18 and 80 years of age, inclusive;

          -  Have a body mass index (BMI) ≥18 and <35.0 kg/m2;

          -  Be in good general health with no clinically relevant abnormalities based on the
             medical history, physical examination, clinical laboratory evaluations (hematology,
             clinical chemistry, and urinalysis), and 12 lead electrocardiogram;

          -  Women of child bearing potential must have a negative pregnancy test at Screening and
             prior to randomization.

          -  Women of child-bearing potential must use 2 methods of acceptable birth control from
             Screening until 3 months after the last dose of study drug;

          -  Male subjects with partners of child-bearing potential (as defined in Inclusion No. 8)
             must use 2 methods of acceptable birth control, 1 of which must be a barrier method;

          -  Subjects with chronic cough

          -  Be able to communicate effectively with the Investigator and other study center
             personnel and agree to comply with the study procedures and restrictions

        Exclusion Criteria:

          -  Current smoker;

          -  Individuals who have given up smoking within the past 6 months, or those with >20
             pack-year smoking history(chronic cough subjects), or >10 pack-year smoking history
             (healthy subjects);

          -  History of upper respiratory tract infection or recent significant change in pulmonary
             status within 4 weeks prior to Screening or prior to randomization;

          -  History of concurrent malignancy or recurrence of malignancy within 2 years prior to
             Screening (with the exception of < 3 excised basal cell carcinomas);

          -  History of a diagnosis of drug or alcohol dependency or abuse within the last 3 years;

          -  In the opinion of the Principal Investigator, an uncontrolled or unstable clinically
             significant neurological, psychiatric, respiratory, cardiovascular, peripheral
             vascular, gastrointestinal, hepatic, pancreatic, endocrinological, hematological, or
             immunological disorder or an active infection;

          -  Clinically significant abnormal electrocardiogram (ECG) at Screening

          -  Significantly abnormal laboratory tests at Screening

          -  Breastfeeding;

          -  In the judgement of the Principal Investigator, other severe, acute, or chronic
             medical or psychiatric condition or laboratory abnormality that may increase the risk
             associated with trial participation or investigational product administration or may
             interfere with the interpretation of trial results and would make the subject
             inappropriate for entry into this trial.