A Phase 2 Study of VX-950 in Combination With Peginterferon Alfa-2a (Pegasys®), With Ribavirin (Copegus®) in Subjects With Genotype 1 Hepatitis C Who Have Not Received Prior Treatment

Inclusion Criteria:

- Hepatitis C virus Genotype 1 with detectable plasma HCV RNA

- Have been infected with Hepatitis C virus for >6 months.

- Seronegative for HbsAg and HIV1 and HIV2

- Must agree to use 2 methods of contraception, including 1 barrier method, during
and for 24 weeks after the completion of the study (unless the subject is a female of
documented non-child-bearing potential)

- Female subjects must have a negative pregnancy test at all visits before the first
dose.

Exclusion Criteria:

- Received any approved or investigational drug or drug regimen for the treatment of
hepatitis C.

- Any medical contraindications to Peg-IFN-a-2a or RBV therapy

- Any other cause of significant liver disease in addition to hepatitis C; this may
include but is not limited to, hepatitis B, drug or alcohol-related cirrhosis,
autoimmune hepatitis, hemochromatosis, Wilson's disease, Nonalcoholic Steatohepatitis
(NASH) or primary biliary cirrhosis.

- Diagnosed or suspected hepatocellular carcinoma.

- Histologic evidence of hepatic cirrhosis (including compensated cirrhosis) based on a
liver biopsy taken within 2 years before Study start

- Alcohol abuse or excessive use in the last 12 months.

- Participation in any investigational drug study within 90 days before drug
administration or participation in more than 2 drug studies in the last 12 months
(exclusive of the current study).