The purpose of this open-label study is to assess the safety, antiviral activity, and pharmacokinetics of 9 subcutaneous injections of miravirsen monotherapy (5 weekly doses over 5 weeks, followed by a further 4 doses once every other week over 7 weeks) over a total of 12 weeks of treatment. The subjects enrolled in this study are chronically infected with HCV genotype 1 and are null responders to treatment with peg IFNα/RBV therapy.

Inclusion Criteria:

• Diagnosis of chronic hepatitis C
• HCV genotype 1
• BMI 18-38 kg/m2
• Null responder to pegylated interferon alpha and ribavirin

Exclusion Criteria:

• Co-infection with hepatitis B virus (HBV) or human immunodeficiency virus (HIV)
• Significant liver disease in addition to hepatitis C
• Decompensated liver disease medical history or current clinical features
• Histologic evidence of hepatic cirrhosis
• Concurrent clinically significant medical diagnosis (other than CHC)
• Concurrent social conditions (e.g. drugs of abuse, alcohol excess, poor living accommodation)
• Clinically significant illness within 30 days preceding entry into the study
• Participated in an investigational drug study within 30 days or 5 half-lives, whichever is longer, prior to the start of study medication
• History of clinically significant allergic drug reactions