Study of the Efficacy, Safety, and Tolerability of Serlopitant for the Treatment of Refractory Chronic Cough

Inclusion Criteria:

- Female and males between 18 and 80 years of age

- Have a diagnosis of treatment refractory chronic cough or unexplained cough for at
least one year

- Chest radiograph or computed tomography (CT) Thorax within the last 5 years not
demonstrating any abnormality considered to be significantly contributing to the
chronic cough

- At Screening have a score of ≥ 40mm on the Cough Severity VAS

- At Baseline (Day 0) have a score of ≥ 40mm on the Cough Severity VAS

- All female subjects who are of childbearing potential must practice highly effective
contraception (i.e., pregnancy prevention method with a failure rate of < 1% per year)
from the time of the initial screening visit until 4 weeks after last dose of study
drug. Please refer to the protocol for acceptable methods of contraception

Exclusion Criteria:

- Prior treatment with serlopitant or other NK1-R antagonist

- Presence of any medical condition or disability that could interfere with study

- History of hypersensitivity to serlopitant or any of its components

- Currently pregnant or male partner of pregnant female

- Females of childbearing potential who are unable or unwilling to use adequate
contraception or who are breast feeding

- Current smoker or individuals who have given up smoking within the past 12 months

- FEV1/FVC < 60%

- Body mass index (BMI) <18 kg/m2 or ≥ 40 kg/m2 at Screening

- History of upper or lower respiratory tract infection or recent significant change in
pulmonary status within 4 weeks of the Baseline Visit (Day 0)

- History of cystic fibrosis

- History of opioid use within 1 week of the Baseline Visit (Day 0)

- Requiring concomitant therapy with prohibited medications

- Treatment with biologic therapies within 8 weeks or 5 half-lives prior to the Baseline
Visit (Day 0), whichever is longer

- Treatment with strong CYP3A4 inhibitors within 4 weeks prior to the Baseline Visit
(Day 0)

- Treatment with any investigational therapy within 4 weeks (investigational biologic
therapies within 8 weeks) prior to the Baseline Visit (Day 0)

- Serum creatinine, total bilirubin, alanine aminotransferase (ALT) or aspartate
aminotransferase (AST) > 2x the upper limit of normal (ULN) during screening

- Positive test for any drug of abuse

- History of malignancy within 5 years prior to the Baseline Visit (Day 0), with the
exception of completely treated and non-metastatic basal cell carcinoma or squamous
cell carcinoma of the skin

- Any known psychiatric diagnosis meeting DSM-5 criteria which may confound the
assessment of serlopitant safety or efficacy, or interfere with the subject's ability
to comply with protocol-mandated activities, within 3 years prior to randomization.
Examples of such DSM-5 diagnoses include but are not limited to major depressive
disorder, bipolar disorder, schizophrenia, psychotic disorder, intellectual
disability, severe alcohol use disorder.

- Known active hepatitis infection

- Known history of human immunodeficiency virus (HIV) infection