A Study to Evaluate Treatment of Hepatitis C Virus Infection in Pediatric Subjects

Inclusion Criteria:

1. Positive anti-HCV Ab and HCV RNA greater than or equal to 1000 IU/mL at the time of
screening.

2. HCV genotype 1 for enrollment into Part 1 and genotype 1 or 4 for enrollment into Part
2.

3. Parent or legal guardian with the willingness and ability to provide written informed
consent and participant willing and able to give assent, as appropriate for age and
country.

Exclusion Criteria:

1. Women who are pregnant, breastfeeding or are considering becoming pregnant

2. Use of known strong inducers and inhibitors (e.g., gemfibrozil) of cytochrome P450 2C8
(CYP2C8) in participants receiving dasabuvir, or strong or moderate inducers of CYP3A,
within 2 weeks or 10 half lives, whichever is longer, of the respective
medication/supplement prior to study drug administration.

3. Positive test result for Hepatitis B surface antigen (HbsAg) or anti-HIV antibody (HIV
Ab) test.

4. Current enrollment in another interventional clinical study, previous enrollment in
this study, prior or current use of any investigational or commercially available
anti-HCV agents other than IFNs or RBV or receipt of any investigational product
within 6 weeks prior to study drug administration.