A Dose Escalation Study of AF-219 in Refractory Chronic Cough

Inclusion Criteria:

- Chest radiograph or CT thorax within the last 12 months not demonstrating any
abnormality considered to be significantly contributing to the chronic cough

- Refractory chronic cough for at least one year: a cough that is unresponsive to at
least 8 weeks of targeted treatment for identified underlying triggers including
reflux disease, asthma and post-nasal drip or unexplained cough: a cough for which no
objective evidence of an underlying trigger can be determined after investigation

- Score of ≥ 40mm on the Cough Severity VAS at Screening

- Women of child-bearing potential must use 2 forms of acceptable birth control method
from Screening through the Follow-Up Visit.

- Male subjects and their partners of child-bearing potential must use 2 methods of
acceptable birth control from Screening until 3 months after the last dose of study
drug.

- Written informed consent.

- Willing and able to comply with all aspects of the protocol.

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 ACE-inhibitor as the potential cause of a subject's cough, or
requiring treatment with an ACE-inhibitor during the study or within 4 weeks prior to
the Baseline Visit (Day 0)

- 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/m2 or ≥ 37 kg/m2

- History of concurrent malignancy or recurrence of malignancy within 2 years prior to
Screening (not including subjects 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 mm Hg or a diastolic blood pressure
(DBP) >90 mm Hg

- 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 AF-219) 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