Patient description: A 53-year-old man presents with chronic HCV infection for the past 2 years. His past medical history is only significant for inguinal hernia surgery when he was 20 years old. He is on IFN (100 mg/week) plus RBV (400 mg/day) combination therapy for the past 9 months. Direct antiviral drugs were added to his treatment 6 months ago. His medical record shows previous positive HCV RNA tests as well as positive enzyme immunoassay for anti-HCV-antibodies. The recent biopsy was negative for hepatocellular carcinoma and was only remarkable for chronic inflammation compatible with a chronic viral hepatitis. There is no evidence of alcoholic liver disease, bleeding from esophageal varices, hemochromatosis, autoimmune hepatitis or metabolic liver disease. He is an alert male with no acute distress. His BP: 130/75, HR: 90/min and BMI: 27. His abdomen is soft with no ascites or tenderness. The lower extremities are normal with no edema.

Clinical trial eligibility criteria: eligible ages (years): 20.0-65.0,  Chronic Hepatitis C for Part A: To be eligible to participate in this study, subjects must meet all of the following at screening: 1. Male or female between 20 to 55 years of age inclusive 2. For females, not breast-feeding, not pregnant, post-menopausal for at least 2 years, surgically sterile, or willing to use a double barrier method [intrauterine device (IUD) plus condom, spermicidal gel plus condom] of contraception, or other effective contraceptive methods from screening until 30 days after the last dose of study drug 3. For males, willing to use a reliable form of contraception (use of a male condom with spermicide or a partner fulfilling the above criteria), or abstinence from screening until 30 days after the last dose of study drug 4. Body weight ≥ 50 kg inclusive and body mass index (BMI) in the range of 19.0 to 30.0 kg/m2, extremes included 5. Good physical and mental health conditions on the basis of medical history and vital signs performed at screening 6. Healthy on the basis of clinical laboratory tests performed at screening. If the results are outside the normal reference ranges, the subject may be included only if the investigator judges the abnormalities or deviations from normal not to be clinically significant. This determination must be recorded in the subject's source document and initialed by the investigator. This is not applicable to the laboratory abnormalities listed in the  [using the Division of Microbiology and Infectious Diseases (DMID) Adult Toxicity criteria-see Section 13.3]. 7. Non-smoking for at least 3 months prior to screening, to be confirmed by a urine cotinine dipstick test 8. 12-lead electrocardiogram (ECG) consistent with normal cardiac conduction and function Heart rate (HR) between 50 and 100 bpm QTcF interval ≤ 430 ms (male) or ≤ 450 ms (female) QRS interval lower than 120 ms PR interval ≤ 200 ms Willing to abstain from caffeine or xanthine-containing beverages and food, including coffee and tea, alcohol, grapefruit juice, and bitter oranges during the study period 10. Willing to sign an Informed Consent Form (ICF) indicating that he or she understands the purpose of and procedures required for the study and is willing to participate in the study for Part A: Subjects must be excluded if they meet any of the following 1. Breast-feeding or pregnant female 2. History of heart arrhythmias (any clinically relevant) or having baseline prolongation of QTcF interval > 430 ms (male) or > 450 ms (female), history of risk factors for Torsade de Pointes syndrome (hypokalemia, family history of long QT syndrome), or a HR (supine pulse as obtained from vital signs) < 50 bpm or > 100 bpm 3. History or suspicion of current use of alcohol, barbiturate, amphetamine, recreational or narcotic drug use, which in the investigator's opinion would compromise subject's safety and/or compliance with the study procedures 4. Hepatitis A, B, or C infection (confirmed by hepatitis A antibody IgM, hepatitis B surface antigen, or hepatitis C virus antibody, respectively) or HIV-1 or HIV-2 infection (confirmed by CLIA test) at study screening 5. Clinically relevant, currently active or underlying gastrointestinal, cardiovascular-, nervous system, psychiatric, metabolic, renal, hepatic, respiratory, inflammatory, or infectious disease 6. History of drug allergy such as, but not limited to, sulfonamides and penicillins, or drug allergy witnessed in previous trials with investigational drugs 7. Any condition that, in the opinion of the investigator, would compromise the study or the well-being of the subject or prevent the subject from meeting or performing study requirements 8. Use of concomitant medication, including over-the-counter product, herbal medication and dietary supplement in a period of 14 days before the study 9. Donation of blood or plasma over 250 mL within 60 days preceding the study 10. Subjects with one or more of the following laboratory abnormalities at screening as defined by DMID Adult Toxicity Table Hemoglobin grade 1 or greater (≤ 10.5 gm/dL) Platelet count grade 1 or greater (< 100,000/mm3)