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)

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