DORA

An open-label study to assess the pharmacokinetics (PK), safety, and efficacy of an active drug in pediatric participants divided into 4 age groups: 3 to < 6, 6 to < 9, 9 to < 12, and 12 to < 18 years of age. Within each age group, some participants will be enrolled for intensive pharmacokinetics (IPK) to characterize the PK of a particular age group and the remainder of participants will be enrolled for the evaluation of safety and efficacy of each age group. Intensive PK sampling is designed to allow for dose adjustment, based on available PK and clinical data to achieve therapeutic exposures that have been safe and efficacious in adults.

Part 1 of the study will enroll participants into Cohort 1; Cohort 1 will include participants who are in 12 to < 18 years of age who can swallow the adult formulation of the active drug. Part 2 of the study will enroll participants in the remaining age groups into Cohorts 2, 3, and 4; participants in these cohorts will receive the pediatric formulation of the active drug. All participants will receive the active drug for 8, 12, or 16 weeks depending on their hepatitis C virus (HCV) genotype, cirrhosis, and prior treatment experience status.