Study to Investigate Pharmacokinetics, Safety and Efficacy of Sofosbuvir/Velpatasvir/Voxilaprevir (SOF/VEL/VOX) Fixed Dose Combination (FDC) in Adolescents and Children With Chronic Hepatitis C Virus (HCV) Infection

A Phase 2, Open-Label, Multicenter, Multi-cohort Study to Investigate the Pharmacokinetics, Safety and Efficacy of Sofosbuvir/Velpatasvir/Voxilaprevir Fixed Dose Combination in Adolescents and Children With Chronic HCV Infection

The primary objective of this study is to evaluate the steady-state pharmacokinetics (PK) and confirm the age-appropriate dose of sofosbuvir/velpatasvir/voxilaprevir (SOF/VEL/VOX) fixed-dose combination (FDC) in pediatric participants with chronic hepatitis C virus (HCV) infection.

Participants will receive placebo to match SOF/VEL/VOX FDC to assess ability to swallow tablets at screening up to Day 1.

Key Inclusion Criteria:

• Consent of parent or legal guardian required

• Chronic HCV infection

• Screening laboratory values within defined thresholds

• Individuals must have a determination of prior treatment status:

  • DAA-naive is defined as either:

    • Treatment naive with no prior exposure to any interferon (IFN), ribavirin (RBV), or approved or experimental HCV-specific DAA
    • Treatment experienced with an IFN-based regimen and no prior exposure to an approved or experimental HCV-specific DAA

  • DAA-experienced is defined as prior exposure to a regimen including any DAA (eg, non-structural protein (NS)3/4A protease inhibitor, NS5A inhibitor, or NS5B nucleotide/nucleoside inhibitor)

Key Exclusion Criteria:

• History of clinically significant illness or any other medical disorder that may interfere with subject treatment, assessment or compliance with the protocol
• Co-infection with human immunodeficiency virus (HIV), acute hepatitis A virus (HAV) or hepatitis B virus (HBV)
• Clinical hepatic decompensation (eg, clinical ascites, encephalopathy, and/or variceal hemorrhage)
• Pregnant or nursing females
• Known hypersensitivity to study medication
• Use of any prohibited concomitant medications as within 28 days of the Day 1 visit

Note: Other protocol defined Inclusion/Exclusion criteria may apply.