Effect of Gefapixant (MK-7264/AF-219) on Cough Reflex Sensitivity in Healthy and Chronic Cough Participants (MK-7264-014)
Condition: Refractory Chronic Cough
MeSH terms: Cough
Intervention: Gefapixant 100 mg; Placebo
Intervention description: Gefapixant 100 mg (2 x 50 mg tablets), administered orally as a single dose in treatment Period 1 or treatment Period 2; Placebo (two tablets matching gefapixant 50 mg), administered orally as a single dose in treatment Period 1 or treatment Period 2
Phase: Phase 2
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Chronic cough and healthy participants were randomly assigned to receive gefapixant and placebo in one of two treatment sequences: Sequence A (placebo in treatment period 1, then gefapixant in treatment period 2) or Sequence B (gefapixant in treatment period 1, then placebo in treatment period 2). There was at least a 48-hour washout between the treatment periods. Daytime cough monitoring was performed in chronic cough participants only.
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Enrollment: 36.0
Sex: All
Minimum age: 18 Years
Maximum age: 80 Years
Healthy volunteers: Accepts Healthy Volunteers

Summary:

      The primary objective of this study was to assess the effect of a single dose of gefapixant
      100 mg on cough reflex sensitivity to various challenge agents (capsaicin, citric acid,
      adenosine triphosphate [ATP], and distilled water) in healthy and chronic cough participants.
    

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 kg/m^2;

          -  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;

          -  Be non-smokers for at least 5 years;

          -  If a female of child-bearing potential (I. e., have not undergone a hysterectomy or
             bilateral oophorectomy) or not post-menopausal (defined as no menses for at least 12
             months), agree to use 2 forms of acceptable birth control; or if a male, they and/or
             their partner of child-bearing potential agree to use 2 forms of acceptable birth
             control;

          -  Be able to communicate effectively with the Investigator and other study center
             personnel and agree to comply with the study procedures and restrictions.

          -  Subjects with chronic cough must have treatment-refractory chronic cough for at least
             one year, with no objective evidence of an underlying trigger (e. g., asthma)

        Exclusion Criteria:

          -  History of upper respiratory tract infection or recent significant change in pulmonary
             status within 4 weeks of the Baseline Visit (Day 0);

          -  Have acute worsening of asthma;

          -  Do not cough during the ATP or Capsaicin or Citric acid challenge at Screening or only
             cough twice at the two highest concentrations of the test solution;

          -  History of concurrent malignancy or recurrence of malignancy within 2 years prior to
             Screening (not including subjects with <3 excised basal cell carcinomas);

          -  History of a diagnosis of drug or alcohol dependency or abuse within approximately the
             last 3 years;

          -  Clinically significant abnormal electrocardiogram (ECG) at Screening;

          -  Significantly abnormal laboratory tests at Screening;

          -  Pregnant or breastfeeding;

          -  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, in the judgment of the Investigator or Sponsor, would make the
             subject inappropriate for entry into this trial.