A Study of Hepatitis C Virus (HCV) Polymerase Inhibitor Pro-Drug in Combination With PEGASYS Plus COPEGUS Compared With PEGASYS Plus COPEGUS in Patients With Chronic Hepatitis C Genotype 1 Infection.

This 7 arm study will determine the optimal treatment combination, based on efficacy and
safety. Patients with chronic hepatitis C (CHC), genotype 1, will be randomized to one of 7
treatment groups. Groups 1, 2, 4, 5 and 6 will receive triple combination treatment with HCV
polymerase inhibitor pro-drug (at doses of 500, 1000 or 1500mg po bid) plus PEGASYS (90 or
180 micrograms sc weekly) plus Copegus (1000 or 1200mg po qd) for 24 weeks, followed by 24
weeks of open label Standard of Care (PEGASYS 180 micrograms sc weekly plus Copegus
1000/1200mg po qd). Group 3 will receive HCV polymerase inhibitor pro-drug 500mg po bid plus
PEGASYS 180 micrograms sc weekly plus Copegus 1000/1200mg po qd for 24 weeks; after 24
weeks, those achieving a rapid virological response (RVR) will stop all medication, and
non-RVR patients will remain on triple combination for an additional 24 weeks. Group 7 will
receive standard of care (SOC) for 48 weeks. There will be a 24 week period of
treatment-free follow-up for all treatment groups. The anticipated time on study treatment
is 3-12 months, and the target sample size is 100-500 individuals.