A Dose Escalation Study of Gefapixant (AF-219/MK-7264) in Refractory Chronic Cough (MK-7264-010)

Exclusion Criteria

• •Current smoker
• •Individuals who have given up smoking within the past 6 months, or those with \>20 pack-year smoking history
• •Treatment with an angiotensin converting enzyme (ACE)-inhibitor as the potential cause of a participant's cough, or requiring treatment with an ACE-inhibitor during the study or within 4 weeks prior to the Baseline Visit (Day 0)
• •Forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) \< 60%
• •History of upper respiratory tract infection or recent significant change in pulmonary status within 4 weeks of the Baseline Visit (Day 0)
• •History of opioid use within 1 week of the Baseline Visit (Day 0)
• •Requiring concomitant therapy with prohibited medications
• •Body mass index (BMI) \<18 kg/m\^2 or ≥ 37 kg/m\^2
• •History of concurrent malignancy or recurrence of malignancy within 2 years prior to Screening (not including participants with \<3 excised basal cell carcinomas)
• •History of a diagnosis of drug or alcohol dependency or abuse within approximately the last 3 years
• •Any condition possibly affecting drug absorption (e.g., gastrectomy, gastroplasty, any type of bariatric surgery, vagotomy, or bowel resection)
• •Screening systolic blood pressure (SBP) \>160 mmHg or a diastolic blood pressure (DBP) \>90 mmHg
• •Clinically significant abnormal electrocardiogram (ECG) at Screening
• •Personal or family history of congenital long QT syndrome or family history of sudden death
• •Cardiac pacemaker
• •Significantly abnormal laboratory tests at Screening
• •Breastfeeding
• •Treatment with an investigational drug (except gefapixant) or biologic within 60 days preceding the first dose of study medication or plans to take another investigational drug or biologic within 30 days of study completion
• •Blood donation within 56 days or plasma donation within 7 days prior to dosing
• •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