Efficacy and Safety of Uprifosbuvir (MK-3682) + Ruzasvir (MK-8408) in Treating Hepatitis C Virus Infection Genotypes 1-6 (MK-3682-041)

Any GT that meets virologic futility criteria will be given the option of extending treatment
with Uprifosbuvir + RZR to 16 weeks with ribavirin (RBV) added.

Inclusion Criteria:

- has HCV RNA (≥10,000 IU/mL in peripheral blood) at the time of screening

- has documented chronic HCV GT1, GT2, GT3, GT4, GT5, or GT6 (with no evidence of
non-typeable or mixed GT)

- is a female who is not of reproductive potential, or is a female of reproductive
potential who agrees to avoid becoming pregnant from two weeks prior to Day 1 through
14 days after the last dose of study drug via abstinence or use of two approved
contraceptives

- is C or NC

- if coinfected with HIV, has documented HIV infection prior to Day 1, and either does
not use an antiretroviral therapy (ART) or has well-controlled HIV on stable ART (at
least 4 weeks prior to study entry)

Exclusion Criteria:

- has evidence of decompensated liver disease

- is C and is Child-Pugh Class B or C, or has a Child-Tucotte-Pugh score >6

- is coinfected with hepatitis B virus (hepatitis B surface antigen or hepatitis B core
antibody positive)

- is coinfected with HIV and has a recent (within 6 months prior to screening)
opportunistic infection

- has a history of malignancy other than adequately treated basal cell or squamous cell
skin cancer or in situ cervical cancer or carcinoma in situ within 5 years of signing
informed consent

- is C and has evidence (liver imaging within 6 months prior to Day 1) of hepatocellular
carcinoma (HCC) or is under evaluation for HCC

- has participated in another investigational drug study within 30 days of signing
informed consent

- is a female who is pregnant or breastfeeding or expecting to conceive or donate eggs
from Day 1 through 6 months after the last dose of study drug or longer if dictated by
local regulations, or is a male subject who is expecting to donate sperm from Day 1
through 14 days after the last dose of study drug or longer if dictated by local
regulations, or is a male whose female partner(s) is/are pregnant or breastfeeding

- has clinically relevant alcohol or drug abuse within 12 months of screening

- has any of the following conditions: organ transplants other than cornea and hair;
poor venous access; history of gastric surgery; clinically significant cardiac
abnormality/dysfunction; any major medical condition which, in the opinion of the
investigator, might interfere with participation; hospitalization within 3 months
prior to enrollment; any condition that might require hospitalization; any condition
requiring or likely to require chronic systemic administration of corticosteroids,
tumor necrosis factor (TNF) antagonists, or immunosuppressant drugs; a
life-threatening serious adverse event (SAE) during screening; or hepatitis not caused
by HCV