Subjects will be enrolled in 1 of 3 dose cohorts (low, medium and high). Each cohort will consist of 8 subjects with a 3:1 randomization ratio for ASP015K to placebo. Subjects will be confined to the clinic for study procedures until day 4 (5 days). After all subjects in a dose cohort have completed study procedures through day 4, a decision will be made whether or not dosing and enrollment of the next dose cohort should occur, which will only take place after a review of the safety and tolerability data through day 4 of the most recent dose cohort and any additional reported adverse events (AEs) for previously dosed cohorts.
The purpose of this study is to assess the safety, tolerability and pharmacokinetics of single ascending doses of ASP015K.