Study of Grazoprevir (MK-5172) + Elbasvir (MK-8742) + Ribavirin in Participants With Chronic Hepatitis C Who Failed Prior Direct-Acting Antiviral Therapy (MK-5172-048)

Inclusion criteria: * Documented chronic HCV GT1 infection (with no evidence of non-typable or mixed genotype) * Absence of cirrhosis, or cirrhosis with these criteria: METAVIR F4, or Fibroscan with result \>12.5 kPa, or FibroSure® (Fibrotest®) score of \>0.75 + aspartate aminotransferase (AST): platelet ratio index (APRI) of \>2- Prior regimen containing an approved DAA (boceprevir, telaprevir, simeprevir, or sofosbuvir), pegylated interferon, and/or RBV * Participants of reproductive potential must agree to remain truly abstinent or use (or have their partner use) 2 acceptable methods of birth control from at least 2 weeks prior to Day 1 and continue until at least 6 months after last dose of study drug, or longer if dictated by local regulations Exclusion criteria: * Received any HCV regimen containing a DAA with the exception of boceprevir, telaprevir, simeprevir, or sofosbuvir in combination with pegylated interferon and/or RBV * Evidence of decompensated liver disease or cirrhosis * Co-infected with hepatitis B virus or human immunodeficiency virus (HIV) * 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 * Evidence of hepatocellular carcinoma (HCC) or under evaluation for HCC * 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 * Clinically-relevant drug or alcohol abuse within 12 months of screening * Pregnant, 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 * Male participant whose female partner (s) is/are pregnant * Organ transplants (including hematopoietic stem cell transplants) other than cornea and hair * Poor venous access * History of gastric surgery (e.g., stapling, bypass) or history of malabsorption disorders (e.g., celiac sprue disease) * Hemoglobinopathy, including, but not limited to, thalassemia major * Any medical condition requiring, or likely to require, chronic systemic administration of corticosteroids during the course of the trial * Evidence or history of chronic hepatitis not caused by HCV, including but not limited to nonalcoholic steatohepatitis (NASH), drug-induced hepatitis, and autoimmune hepatitis