A Pharmacokinetic Study of Avanfil in Healthy Young Male Subjects

Inclusion Criteria: * Cohort A: Adult male subjects of 18 to 45 years of age inclusive Cohort B: Adult male subjects at least 65 years of age * All subjects must be medically healthy with no clinically significant screening results. * Male subjects should be willing to use a condom and spermicide during sexual activity for 90 days after last dosing of Avanafil and be willing to not donate sperm for 90 days after dosing. Exclusion Criteria: Major exclusion criteria for all subjects 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 investigator * Systolic blood pressure \< 90 or \>150 mmHg * Diastolic blood pressure \< 50 or \> 95 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 urine alcohol test * Positive urine drug screen * Positive urine cotinine test, positive serology for HIV, HCV, HBsAg * Young males who have undergone vasectomy cannot participate in this-study * Additional exclusion criteria are listed in Section 4.2.