MK-5172 Administered With Peginterferon and Ribavirin in Treatment-Naïve Patients With Chronic Hepatitis C (MK-5172-003 AM6)

Amendment 5 allows treatment-naïve participants with chronic hepatitis C and compensated
cirrhosis to be enrolled and receive MK-5172 100 mg in combination with PegIFN alfa-2b and
ribavirin, without a corresponding control arm.

Inclusion Criteria:

- Has previously documented chronic hepatitis C genotype 1 (CHC GT 1) infection

- Has hepatitis C virus (HCV) ribonucleic acid (RNA value) ≥10,000 IU/mL

- Body weight ≥40 kg (88 lbs) and ≤125 kg (275 lbs)

- Absence (no medical history or physical findings) of ascites, bleeding esophageal
varices, hepatic encephalopathy, or other signs and symptoms of decompensated liver
disease

- Had a liver biopsy within 3 years of screening or between screening and Day 1 with
histology consistent with CHC and no evidence of cirrhosis or hepatocellular
carcinoma or no other cause for chronic liver disease (for participants with
compensated cirrhosis, any liver biopsy demonstrating cirrhosis regardless of length
of time since biopsy)

- Female of childbearing potential or a male with female sexual partner who is of
childbearing potential agrees 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

- For participants with compensated cirrhosis, evidence of cirrhosis without evidence
of hepatocellular carcinoma (confirmed by ultrasound within 4 weeks prior)

Exclusion Criteria:

- Is pregnant, breastfeeding, or plans to become pregnant or donate eggs

- Is human immunodeficiency virus (HIV) positive or known to be co-infected with
hepatitis B virus

- Has received prior approved or investigational treatment for hepatitis C

- Has evidence of hepatocellular carcinoma or is under evaluation for hepatocellular
carcinoma

- For participants with compensated cirrhosis: alphafetoprotein level of ≥100 ng/mL

- Has evidence of active or suspected malignancy, or a history of malignancy, within
the last 5 years

- Has evidence or history of chronic hepatitis not caused by HCV

- Is diabetic and/or hypertensive with clinically significant ocular examination
findings: retinopathy, cotton wool spots, optic nerve disorder, retinal hemorrhage,
or any other clinically significant abnormality

- Has any known medical condition that could interfere with the patient's participation
in and completion of the study

- Pre-existing psychiatric condition including but not limited to moderate or severe
depression, suicidal or homicidal ideation or attempt, schizophrenia, psychosis,
bipolar disorder, post traumatic stress disorder, or mania

- Is currently participating or has participated in a study with an investigational
compound or device within 30 days of signing informed consent

- Member or family member of study staff