This is a randomized, double-blind, placebo-controlled, crossover, dose escalation study of bradanicline in subjects with chronic cough

This study will have two 21-day treatment periods separated by a 14-day washout period. There will be a 14-day follow-up period.

Inclusion Criteria:

• Chest radiograph or computed tomography (CT) scan of the thorax within the last 1 year not demonstrating any abnormality considered to be significantly contributing to the refractory chronic cough
• Diagnosis of refractory chronic cough or unexplained cough for at least one year
• Women of child-bearing potential who use 2 forms of acceptable birth control method
• Male subjects and their partners of child-bearing potential who use 2 methods of acceptable birth control
• Has provided written informed consent

Exclusion Criteria:

• Current smoker (cigarettes or e-cigarettes) or has given up smoking within the past 12 months
• Currently taking an ACE-inhibitor or requiring treatment with an ACE-inhibitor during the study or within 12 weeks prior to the Baseline Visit
• Has an upper or lower respiratory tract infection or recent significant change in pulmonary status within 4 weeks of the Baseline Visit
• Has a history of cystic fibrosis
• Has a history of malignancy within 5 years prior to the Baseline Visit
• Has active hepatitis infection
• Has a history of human immunodeficiency virus (HIV) infection
• Has a positive test for any drug of abuse
• Has a history of hypersensitivity to bradanicline or any of its components