The purpose of this study was to determine the safety, tolerability and pharmacokinetics of sequential ascending doses of JTK-853 administered for 14 days in healthy subjects and also to determine the effect of a single dose of ketoconazole on the steady-state pharmacokinetic profile of JTK-853 and its metabolite M2 (one cohort only).

Inclusion Criteria:

1. Body Mass Index (BMI) ≥18.0 kg/m2 and ≤30.0 kg/m2
2. Non-smokers or subjects who have stopped smoking at least 6 months prior to the Screening Visit
3. Female subjects must be either surgically sterile or postmenopausal

Exclusion Criteria:

1. History or presence of cardiac disease, including a family history of long-QT syndrome or unexplained sudden death
2. Have used any prescription medication, herbal product, or over-the-counter (OTC) medication (except acetaminophen) within four weeks prior to Day -1