['hepatitis c infection']
['grazoprevir + elbasvir', 'ribavirin']

        Inclusion Criteria:

          -  Documented chronic HCV GT1, GT4, or GT6 with no evidence of non-typable or mixed
             genotype infection (positive for anti-HCV antibody, HCV ribonucleic acid [RNA], or any
             of the listed GTs at least 6 months prior to screening must be confirmed by screening
             lab results)

          -  Cirrhosis defined as liver biopsy showing METAVIR F4; or Fibroscan showing result
             >12.5 kilopascals (kPa); or FibroSure® (Fibrotest®) score of >0.75 and an aspartate
             aminotransferase (AST):platelet ratio index (APRI) of >2

          -  Absence of cirrhosis defined as liver biopsy showing absence of cirrhosis; or
             Fibroscan result of ≤ 12.5 kPa; or Fibrosure® (Fibrotest®) score of ≤ 0.48 and APRI ≤
             1

          -  Previous HCV treatment status of peginterferon/RBV Null responder; or
             peginterferon/RBV Partial responder; or peginterferon/RBV Treatment Relapse

          -  For human immunodeficiency virus (HIV) co-infected participants: documented HIV-1
             infection; currently naïve to treatment with any antiretroviral therapy (ART) and have
             no plans to initiate ART treatment while participating in this study; or be on HIV ART
             for at least 8 weeks prior to study entry (dual nucleoside reverse transcriptase
             inhibitor [NRTI] backbone of tenofovir or abacavir and either emtricitabine or
             lamivudine plus raltegravir (or dolutegravir or rilpivirine) (no changes in HIV
             regimen allowed within 4 weeks of randomization); cluster of differentiation 4 (CD4)+
             T-cell count >200 cells/mm^3 at screening; documented undetectable plasma HIV-1 RNA at
             least 8 weeks prior to screening; participants not on ART, HIV RNA must be <50,000
             copies/mL; must have at least one viable antiretroviral regimen alternative beyond
             their current regimen in the event of HIV virologic failure and the development of
             antiretroviral drug resistance

          -  Agree to use two 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; a male participant who is not (or whose partner is not)
             of reproductive potential is eligible without requiring the use of contraception

        Exclusion Criteria:

          -  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

          -  For participants with cirrhosis, participants who are Child-Pugh Class B or C or who
             have a Pugh-Turcotte (CPT) score >6, must be excluded

          -  Co-infected with hepatitis B virus

          -  Has had previous direct-acting antiviral treatment

          -  History of malignancy <=5 years prior except for adequately treated basal cell or
             squamous cell skin cancer or in situ cervical cancer or carcinoma in situ; or is under
             evaluation for other active or suspected malignancy

          -  Has cirrhosis and liver imaging showing evidence of hepatocellular carcinoma (HCC) or
             is under evaluation for HCC

          -  Taking or plans to take any HIV therapy that includes a ritonavir-boosted or unboosted
             protease inhibitor, efavirenz or etravirine

          -  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

          -  Pregnant, breast-feeding, or expecting to conceive or donate eggs or sperm from Day 1
             and continue until at least 6 months after last dose of study drug, or longer if
             dictated by local regulations; or is a male whose female partner(s) is/are pregnant

          -  History of organ transplant (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
             corticosteroids, tumor necrosis factor (TNF) antagonists, or other immunosuppressant
             drugs during the course of the trial

          -  For participants with HIV, history of opportunistic infection in the preceding 6
             months

          -  For participants with HIV, use of HIV drugs other than a dual NRTI backbone of
             tenofovir or abacavir and either emtricitabine or lamivudine plus raltegravir (or
             dolutegravir or rilpivirine)

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