Elbasvir (EBR)/Grazoprevir (GZR) in Pediatric Participants With Chronic Hepatitis C Infection (MK-5172-079)

The purpose of this study is to assess the pharmacokinetics (PK), safety, and efficacy of oral MK-5172 (a fixed dose combination \[FDC\] tablet containing elbasvir \[EBR\] 50 mg and grazoprevir \[GZR\] 100 mg) and EBR/GZR (varying doses) pediatric granules in pediatric hepatitis C virus (HCV)-infected participants who are 3 to \<18 years of age. Within each age cohort (Cohort 1: 12 to \<18 years of age; Cohort 2: 7 to \<12 years of age; and Cohort 3: 3 to \<7 years of age), a Mini Cohort of 7 participants will be enrolled first. For the oldest cohort (Cohort 1), the Mini Cohort will assess ability to swallow a placebo tablet prior to administering active FDC tablets; participants in Cohorts 2 and 3 will take pediatric granules instead of a tablet.


Eligibility Criteria:
Inclusion Criteria:

* Has documented chronic HCV genotype (GT) 1 or GT4 infection
* Has the following liver disease staging assessment: absence of cirrhosis or compensated cirrhosis
* Has one of the following HCV treatment statuses:
* GT1 and GT4: treatment-naïve (TN), defined as no prior exposure to any interferon (IFN)-containing regimen, ribavirin (RBV), or other HCV-specific direct acting antiviral (DAA) agent
* GT1 only: treatment-experienced (TE) with no previous treatment with HCV specific DAA agents.
* If female is not pregnant, not breastfeeding, and is either not of childbearing potential or follows the contraceptive guidance during the treatment period and for at least 14 days after the last dose of study treatment.

Exclusion Criteria:

* Has evidence of decompensated liver disease manifested by the presence of or history of ascites, esophageal or gastric variceal bleeding, hepatic encephalopathy, or other signs or symptoms of advanced liver disease.
* Is cirrhotic AND has a Child-Turcotte-Pugh score \>6, corresponding to a Child Class B or C.
* Is co-infected with Human Immunodeficiency Virus (HIV).
* Has evidence of past or present hepatitis B infection.
* Has a history of malignancy ≤5 years prior to signing informed consent or is under evaluation for other active or suspected malignancy.
* Female expects to conceive or donate eggs from Day 1 through at least 14 days after the last dose of study treatment or longer.
* Has any of the following conditions: organ transplants other than cornea and hair; poor venous access; history of gastric surgery or malabsorption disorders; any clinically significant cardiac abnormalities/dysfunction that may interfere with participant treatment, assessment, or compliance; any major medical condition which might interfere with participant treatment, assessment, or compliance; history of a medical/surgical condition that resulted in hospitalization within the 3 months prior to enrollment; medical/surgical conditions that may result in a need for hospitalization during the study duration; any medical condition requiring, or likely to require, chronic systemic administration of corticosteroids, tumor necrosis factor antagonists, or immunosuppressant drugs; life-threatening serious adverse event (SAE) during the screening period; history of chronic hepatitis not caused by HCV.
* If female has a positive urine pregnancy test within 24 hours before the first dose of study treatment.
* Is taking or plans to take prohibited medications, or is taking herbal supplements.
* Has had previous HCV direct acting antiviral (DAA) treatment.
* Is currently participating or has participated in a study with an investigational compound within prior 30 days
* Has significant emotional problems or a clinically significant psychiatric disorder that may interfere with participant treatment, assessment, or compliance with the protocol.
* Has clinically relevant drug or alcohol abuse within prior 12 months that may interfere with participant treatment, assessment, or compliance.