This study will examine the effectiveness of 15 days of therapy with SCY-635 in reducing hepatitis C virus (HCV) RNA levels.

Inclusion Criteria:

A potential subject will be eligible for participation in this study if he or she meets all of the following inclusion criteria:

• The subject is either male or female, between the ages of 18 and 65 years (inclusive).
• The subject has read and signed a Subject Informed Consent form to participate in the study. If the subject is not fluent in English, the Subject Informed Consent form must be translated into his or her native language.
• Female subjects of childbearing potential (i.e., women not surgically sterile or at least two years postmenopausal) must agree to utilize one of the following forms of contraception from Screening through completion of the study: abstinence, barrier (condom, diaphragm with spermicide), intrauterine device (IUD), or vasectomized partner (six months minimum). Hormonal contraception (oral, transdermal, implant, or injection) is not permitted during the study period (i.e., from Screening through the Follow-up visit). Note: For women aged <50 years, postmenopausal is defined as at least two years cessation of menses. For women aged ≥50 years, postmenopausal is defined as at least one year cessation of menses. Estrogen replacement is allowed during the study.
• The subject exhibits quantifiable plasma levels of HCV-specific RNA in excess of 100,000 IU/mL as determined by the quantitative Roche COBAS taqMan assay.
• The subject has a negative urine screen for amphetamines, barbiturates, cocaine, opiates, and phencyclidine at Screening.
• If female, the subject has a negative serum pregnancy test at Screening (within 30 days prior to dosing) and a negative urine pregnancy test on Study Day -1.

Exclusion Criteria:

A potential subject will be excluded from participation in the study if he or she meets any of the following exclusion criteria:

• The subject has a history of clinically significant gastrointestinal, renal, hepatic, neurologic, hematologic, endocrine, oncologic, pulmonary, immunologic, psychiatric, or cardiovascular disease, or any other condition which, in the opinion of the Principal Investigator, may jeopardize the safety of the subject or may impact the validity of the study results.
• The subject is infected with any HCV genotype other than genotype 1.
• The subject has documented positive antibody tests for Human Immunodeficiency Virus Types 1 or 2 (p24 antibody specific for HIV-1 or HIV-2) or Hepatitis B virus (HBV) surface antigen (HbSAg) or at Screening exhibits serologic evidence of infection with either HIV-1, HIV-2 or HBV.
• The subject has donated blood within 30 days prior to dosing or donated plasma within 14 days prior to dosing.
• The subject has used any investigational agent within three months prior to dosing.
• The subject has received any FDA-approved anti-HCV therapy (including ribavirin or any product that contains interferon) within three months prior to dosing.
• The subject exhibits evidence of decompensated liver disease, as marked by bilirubin greater than 4 mg/dL, albumin less than 3.0 g/dL, prothrombin time greater than 2 seconds prolonged, or history of bleeding esophageal varices, ascites or hepatic encephalopathy.
• The subject is an organ transplant recipient.
• The subject exhibits ALT values greater than or equal to 2.5 times the upper limit of normal.
• The subject exhibits evidence of hepatocellular carcinoma either by exhibiting a serum alpha-fetoprotein concentration which exceeds 50 mg/L or by exhibiting a mass suggestive of liver cancer by ultrasound or other imaging technology.
• The subject exhibits evidence of ongoing alcohol or substance abuse.