Treatment of Refractory Chronic Cough With PA101

Inclusion Criteria: * Diagnosis of Idiopathic Pulmonary Fibrosis (based on presence of definitive or possible usual interstitial pneumonia UIP pattern on high-resolution computed tomography and after excluding lung diseases associated with environmental and occupational exposure, with connective tissue disease and with drugs; transfer capacity for carbon monoxide corrected for hemoglobin \[TLCOc\] \>25% predicted within 12 months of Screening; and forced vital capacity \[FRC\] \>50% predicted within 1 month of Screening) or Chronic Idiopathic Cough (that is unresponsive to targeted treatment for identified underlying triggers including post-nasal drip, asthmatic/non-asthmatic eosinophilic bronchitis, and gastro-esophageal reflux disease) * Refractory chronic cough for at least 8 weeks * Daytime cough severity score \>40 mm on Cough Severity VAS at Screening * Daytime average cough count ≥15 per hour at Screening * Willing and able to provide written informed consent Exclusion Criteria: * Current or recent history of clinically significant medical condition, laboratory abnormality or illness that could put the patient at risk or compromise the quality of the study data as determined by the investigator * Upper or lower respiratory tract infection within 4 weeks of Screening * History of malignancy treated or untreated within the past 5 years, with the exception of localized basal cell carcinoma or cervix carcinoma in situ * Current or recent history (within 12 months) of excessive use or abuse of alcohol * Current or recent history (within 12 months) of abusing legal drugs or use of illegal drugs or substances * Participation in any other investigational drug study within 4 weeks of Screening * Use of prednisone, narcotic antitussives, baclofen, gabapentin, inhaled corticosteroids, benzonatate, dextromethorphan, carbetapentane, H1 antihistamines, leukotriene modifiers, and cromolyn sodium within 2 weeks of Screening * Pregnant or breastfeeding females, or if of child-bearing potential unwilling to practice acceptable means of birth control or abstinence during the study