Evaluation of S-600918 in Adults With Refractory Chronic Cough

Key Inclusion Criteria: * Having refractory chronic cough (including unexplained chronic cough) for at least 1 year. * If female and of childbearing potential, agreement to use one of the allowed contraceptive methods. * Capable of giving signed informed consent. Key Exclusion Criteria: * Currently smokes or uses potentially irritating inhalational agents (eg, e-cigarettes, smokeless cigarettes, vaping); stopped smoking or using potentially irritating inhalational agents within the last year; or has a smoking history of 20 pack-years or more. * Has chronic obstructive pulmonary disease or uncontrolled asthma. * Has a clinically unstable medical condition. * History of or ongoing significant psychiatric disorder. * History of respiratory tract infection or significant change in lung function or a pulmonary condition in the last 4 weeks. * History of malignancy in the last 5 years. * History of severe drug allergy. * History of alcohol or drug abuse in the last year or currently uses any form of marijuana or illicit drugs. * Has a clinically significant finding on a chest x-ray or chest computed tomography (CT) scan in the last year. * Has systolic blood pressure \> 160 mm Hg or diastolic blood pressure \> 90 mm Hg. * Received S-600918 previously. * Received an investigational drug in the last 3 months. * Received an angiotensin converting enzyme (ACE) inhibitor in the last 3 months or requires such treatment. * Has a positive serologic test for human immunodeficiency virus …