Study of Efficacy and Safety of Grazoprevir (MK-5172) + Elbasvir (MK-8742) in Chronic Hepatitis C Participants With Child-Pugh (CP)-B Hepatic Insufficiency (MK-5172-059)

The study will be conducted sequentially in 3 Parts. Each participant will participate in
only one Part.

Participants will be enrolled in either Part A, Part B, or Part C:

- Part A: CP-B participants will receive grazoprevir 50 mg/elbasvir 50 mg; non-cirrhotic
participants will receive grazoprevir 100 mg/elbasvir 50 mg.

- Part B: CP-B participants will receive grazoprevir 100 mg/elbasvir 50 mg.

- Part C: CP-B participants will receive either grazoprevir 50 mg or 100 mg/elbasvir 50
mg.

Study progression from Part A to Part B and from Part B to Part C will be based upon a
review of safety and efficacy in Parts A and B, respectively. Depending upon safety and
efficacy in Part A, the study may progress directly from Part A to Part C using grazoprevir
50 mg/elbasvir 50 mg, without performing Part B.

Inclusion criteria:

- Has documented chronic HCV GT1 infection (for Arm 4 participants may have GT4 or GT6
infection) with no evidence of non-typable or mixed genotype infection

- Has clinical evidence of hepatic cirrhosis with a score on the Child-Pugh scale from
7 to 9 and not anticipated to receive a liver transplant within the next 36 weeks
(for Arm 1, Arm 3, and Arm 4)

- Has no evidence of cirrhosis (only for Arm 2 )

- Agrees to remain truly abstinent or use (or have their partner use) an acceptable
method of birth control from at least 2 weeks prior to Day 1 and continue until at
least 14 days after last dose of study drug, or longer if dictated by local
regulations

Exclusion criteria:

- Is co-infected with hepatitis B virus or human immunodeficiency virus (HIV)

- Has previously received direct-acting antiviral therapy for HCV

- Has a history of malignancy <=5 years prior to signing informed consent except for
adequately treated basal cell or squamous cell skin cancer or in situ cervical cancer
or carcinoma in situ; or under evaluation for other active or suspected malignancy

- Has cirrhosis and liver imaging results within 4 weeks prior to screening showing
evidence of hepatocellular carcinoma (HCC), or is under evaluation for HCC

- Is currently participating or has participated in a study with an investigational
compound within 30 days of signing informed consent and is not willing to refrain
from participating in another such study during the course of this study

- Has clinically-relevant drug or alcohol abuse within 12 months of screening

- Is pregnant or breast-feeding, or expecting to conceive or donate eggs or sperm from
at least 2 weeks prior to Day 1 and continue throughout treatment and follow up, or
longer if dictated by local regulations

- Has received organ transplants (including hematopoietic stem cell transplants) other
than cornea and hair

- Has poor venous access

- Has a history of gastric surgery (e.g., stapling, bypass) or history of malabsorption
disorders (e.g., celiac sprue disease)

- Requires, or likely to require, chronic systemic administration of corticosteroids
during the course of the trial

- Has evidence or history of chronic hepatitis not caused by HCV, including but not
limited to nonalcoholic steatohepatitis (NASH), drug-induced hepatitis, and
autoimmune hepatitis