A Study of the Combination Regimen MK-5172 and MK-8742 ± Ribavirin in Participants With Chronic Hepatitis C (MK-5172-035)

Part A is being done in treatment-naïve (TN), genotype 1 (GT1), interferon eligible,
non-cirrhotic (N-C) participants with chronic hepatitis C (CHC). Participants will be
assigned randomly to 1 of 2 treatment arms in which they will receive MK-5172 100 mg once
daily (QD) + MK-8742 20 mg or 50 mg QD and twice daily (BID) RBV, or to a treatment arm in
which they will receive MK-5172 100 mg QD + MK-8742 50 mg QD without RBV. Treatment will
last 12 weeks.

In Part B, participants with hepatitis C virus (HCV) GT1 and HCV ribonucleic acid (RNA)
levels of ≥10,000 IU/mL will be randomly assigned to a study arm, based on absence or
presence of cirrhosis (C), whether they are TN or had poor response to previous antiviral
therapy (null responders [NR]), or whether co-infected with human immunodeficiency virus
(HIV); these participants will receive open-label MK-5172 (100 mg) in combination with
MK-8742 (50 mg) ± RBV. Treatment will last 8 to 18 weeks dependent on arm assignment.

In Part C, TN, N-C participants with HCV GT1b and HCV RNA levels of ≥10,000 IU/mL will be
randomly assigned to receive open-label MK-5172 (100 mg) in combination with MK-8742 (50 mg)
± RBV. Treatment will last 8 weeks.

In Part D, TN N-C participants with HCV GT3 and HCV RNA levels of ≥10,000 IU/mL will be
randomly assigned to receive open-label MK-5172 (100 mg) in combination with MK-8742 (50 mg)
+ RBV for 12 or 18 weeks.

Inclusion criteria:

All participants - CHC genotype 1 (GT1) virus infection (Parts A, B, and C) or GT3 virus
infection (Part D) - Female participants of childbearing potential or male participant
with female partners of childbearing potential, must use two acceptable methods of birth
control from ≥2 weeks prior to Day 1 until ≥6 months after last dose of study drug, or
longer if dictated by local regulations

Part A - Absence (no medical history or physical findings) of ascites, bleeding esophageal
varices, hepatic encephalopathy, or other signs or symptoms of advanced liver disease, or
cirrhosis - No evidence of advanced fibrosis, cirrhosis and/or hepatocellular carcinoma by
biopsy or noninvasive testing (FibroScan and/or FibroTest)

Parts B, C, and D - Treatment naïve with or without cirrhosis, or - Prior treatment
failure to Peg-IFN/Ribavirin with or without cirrhosis, or - Co-infected with human
immunodeficiency virus (HIV) without cirrhosis -Absence (no medical history or physical
findings) of ascites, bleeding esophageal varices, hepatic encephalopathy, or other signs
or symptoms of advanced liver disease - Liver disease staging assessment by liver biopsy
or noninvasive testing (FibroScan and/or FibroTest)

Exclusion criteria:

All participants - Non-GT1 HCV infection (Part A, Part B, and Part C) or a non-GT3 HCV
infection (Part D) including a mixed GT infection (with a non-GT1 [Part A, Part B, and
Part C] or non-GT3 [Part D]) or a non-typeable genotype - Evidence of hepatocellular
carcinoma (HCC) or is under evaluation for HCC - Currently participating or 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 study - Diabetic and/or
hypertensive with clinically significant ocular examination findings - History of
depression associated with hospitalization for depression, electroconvulsive therapy, or
resulting in prolonged absence from work and/or significant disruption of daily functions
- Suicidal or homicidal ideations and/or attempt, or history of severe psychiatric
disorders - Clinical diagnosis of substance abuse - Current history of seizure disorder,
stroke, or transient ischemic attack - Immunologically mediated disease - Chronic
pulmonary disease - Clinically significant cardiac abnormalities/dysfunction - Active
clinical gout within the last year - Hemoglobinopathy or myelodysplastic syndromes -
History of organ transplants including hematopoietic stem cell transplants - Poor venous
access - Indwelling venous catheter - History of gastric surgery or malabsorption
disorders - Severe concurrent disease - Evidence of active or suspected malignancy, or a
history of malignancy, ≤5 years before - Pregnant, lactating, expecting to conceive or
donate eggs - Male participant with pregnant female partner - Member/family member of the
investigational study or sponsor staff directly involved with this study - Evidence or
history of chronic hepatitis not caused by HCV

Part A - Not treatment-naïve - Documented to be HIV positive - Taking or planning to take
significant inducers or inhibitors of CYP3A4 substrates or herbal supplements 2 weeks
prior to start of study medications

Parts B, C, and D - Previously received any HCV direct-acting antivirals - Requiring, or
likely to require, chronic systemic administration of corticosteroids during the course of
the trial - For participants diagnosed with diabetes mellitus, documented HbA1c >8.5%