Study to Assess the Efficacy, Safety, and Tolerability of NOC-110 in Adults With Refractory or Unexplained Chronic Cough

This is a phase 2b, randomized, double-blind, placebo-controlled study investigating the efficacy, safety, and tolerability of Taplucainium Inhalation Powder (NOC-110) once daily in adults with refractory or unexplained chronic cough.

Inclusion Criteria: * Refractory or unexplained chronic cough for ≥ 12 months. * Women of childbearing potential agree to follow the protocol specified contraceptive - guidance during the study. * Males who are not vasectomized must agree to use the contraceptive methods defined in the protocol. * Able to provide Informed Consent. Exclusion Criteria: * Previous exposure to taplucainium (formerly NTX-1175) or known allergy or hypersensitivity to taplucainium, its excipients/metabolites, or related compounds. * Participants who are currently participating in another drug or device clinical study * Participants who have participated in an Acute or Chronic Cough investigational study within 60 days before the start of the Screening. * Current diagnosis of chronic obstructive pulmonary disease, bronchiectasis, unexplained pulmonary fibrosis, hemoptysis, bronchial asthma, or other pulmonary disease. * Respiratory tract infection within 4 weeks of Screening or during screening period. * Any female who is pregnant or lactating or wishing to become pregnant. * Donation of \> 1 Unit (450 milliliter or more) of blood within 60 days prior to the first dosing. * Alcohol or drug use disorder within the past 2 years. * Current smoker/vaper or individuals who have given up smoking within the past 6 months of screening, and/or those with \>20 pack-year smoking history. * Current opiate/opioid use or medical history of opiate/opioid use disorder. * History of concurrent malignancy or recurrence of malignancy in the last 2 years. * Body Mass Index of ≥40 kg/m2. * Positive results for human immunodeficiency virus, hepatitis B, or hepatitis C virus. * Unable to refrain from the use of medications and treatments that can impact cough during the study. * Have clinically significant history or evidence of poorly controlled cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrine, neurological, immunological, or psychiatric disorder(s).