Phase I Part 1 (single dose):~Healthy volunteers will be admitted to the clinical research unit on Day -1. There will be five cohorts with 8 subjects per cohort. Five subjects per cohort will receive AFA-281 at either 20, 40, 80, 160 or 300 mg and 3 will receive placebo. Oral capsules will be administered on the morning of Day 1, following a 10-hour fast. Blood draws for assessment of Pharmacokinetic parameters will occur 0.2-1 hr pre-dose and at 0.5-, 1-, 2-, 3-, 4-, 8-, 10, 12-, 16-, 24-, 36-, 48-hr, and up to 72-hr post-dose. Vital signs will be collected at scheduled times following dosing. A 12-lead ECG will be obtained pre-dose and scheduled at 2, 4, 8, 24 hr, and 4- or 5-days post- dose. Various clinical laboratory tests will be drawn on Day -1, within 1 hr prior to dosing, and at scheduled timepoints after dosing while the volunteer is housed in the research center. Subjects of Cohorts 1 - 3 will be released following completion of blood draws and safety assessments up to 48 hours and Cohorts 4 and 5 subjects will return for 72-hour blood draws and Day 4 ECG and safety assessment.~Phase I Part 2 (multiple doses - 14 days):~After assessment of the safety data from the single dose Phase I Part 1, healthy volunteers will be randomized into 3 cohorts with 8 subjects per cohort. Five subjects per cohort will receive AFA-281 and 3 will receive placebo. Oral capsules will be administered twice daily for 14 consecutive days. Routine clinical monitoring will occur as in Part 1. Baseline physical examination, vital signs, clinical lab tests, and ECGs will be performed prior to dosing, at scheduled intervals after dosing, and at the end of the cohort's study period to evaluate the safety and tolerability of AFA-281 and the pharmacokinetic profile of AFA-281. Reports of potential Adverse events will be elicited, and vital signs and 12-lead ECG will be measured in a similar manner to Part 1. Similarly, clinical laboratory tests will be drawn prior to and after dosing.
Phase I Part 1 (single dose):~Double-blind dosing will occur in healthy volunteers in 5 cohorts of 8 subjects each. Six subjects in each cohort will be randomized to receive AFA-281 and 2 subjects will be randomized to receive the matching placebo. At the end of the Part 1 study is to evaluate the safety and tolerability of AFA-281. Following completion of each cohort, bioanalytical analyses will be conducted to evaluate the pharmacokinetic profile.~Phase I Part 2 (multiple dose for 14 days):~Pending the results from Part 1, healthy volunteers will be administered AFA-281 for 14 consecutive days in 3 cohorts. At scheduled intervals after dosing, and at the end of the cohort's study period to evaluate the safety and tolerability of AFA-281 and the pharmacokinetic profile of AFA-281.