The objective of this study is to assess the single dose pharmacokinetics of avanafil in subjects with hepatic impairment and in healthy control subjects.

Inclusion Criteria:

• Male subjects must be 21-75 years of age; inclusive. Healthy control subjects (Cohort 1) must be medically healthy with clinically insignificant screening results and hepatically impaired subjects (Cohorts 2 and 3) must have mild or moderate hepatic impairment based on the Child-Pugh Classification.

Exclusion Criteria:

• Main exclusion criteria for healthy control subjects (Cohort 1) include history or clinical evidence of clinically relevant cardiovascular (including thromboembolic disorders), hepatic, renal, hematologic, endocrine, pulmonary, gastrointestinal, psychiatric or neurological impairment; any clinically significant laboratory abnormalities as judged by the investigatorInvestigator; systolic blood pressure < 90 or >160 mmHg; diastolic blood pressure < 50 or > 90 mmHg; allergy to or previous adverse events with PDE5 inhibitors; use of prescription or over-the-counter drugs that are known to interfere with metabolism by the cytochrome P450 3A4 enzyme within 30 days of screening; use of any investigational drug within 30 days of screening; use of any prescription or over-the-counter drugs or herbal remedies within 14 days of screening; history of alcohol or drug abuse within 18 months, history of smoking within 6 months; positive breath alcohol test; positive serology for HIV, HCV, HBsAg; blood donation or significant blood loss within 56 days of dosing; plasma donation within 7 days of dosing.

Main exclusion criteria for hepatically impaired subjects (Cohorts 2 and 3) include any significant concurrent medical condition or history of significant medical conditions other than hepatic impairment that may affect the interpretation of the data or which otherwise contraindicates participation in this study; acute exacerbation of or unstable hepatic disease, as indicated by worsening of clinical and/or laboratory signs of hepatic impairment, within the 2 weeks preceding study drug administration; history of esophageal variceal bleeding within past 6 months; history of bleeding or non-bleeding gastric varices; history of spontaneous bacterial peritonitis within the past 3 months; history of portosystemic surgical shunt; autoimmune liver disease; history of organ transplant; Wilson's disease; diagnosis of cholestatic liver disease (e.g., primary biliary cirrhosis or primary sclerosing cholangitis); history of recent symptomatic cryoglobulinemia; alcoholic hepatitis, determined clinically or by histology; initiation of any new prescription or over the counter medications within 14 days before study drug administration and hemoglobin < 9.0 g/dL, positive for AFP.