Study to Evaluate the Safety, Tolerability, and Pharmacokinetics of MK-3281 in Healthy and Hepatitis C Infected Male Participants (MK-3281-002)

A 2-Part, Randomized, Double-Blind, Placebo-Controlled, Multiple-Rising Dose Study to Evaluate the Safety, Tolerability, and Pharmacokinetics of MK-3281 in Healthy Male Subjects and Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of MK-3281 in Hepatitis C Infected Male Patients

This study will examine the safety, tolerability and plasma pharmacokinetics of multiple doses of MK-3281 in healthy male participants in Part I, and in Hepatitis C Virus (HCV)-infected male participants in Part II. The clinical efficacy of MK-3281, as measured by viral load reduction, will also be assessed in Part II. The primary hypothesis is that twice daily administration of MK-3281 for 10 days in healthy adult male participants and for 7 days in HCV-infected male participants is sufficiently safe and well tolerated, based on assessment of clinical and laboratory adverse experiences, to permit continued clinical investigation.

The results of this study will guide dose selection for future studies in both healthy participants and HCV-infected participants.

Inclusion Criteria:

• Participant is judged to be in good/stable health based on medical history, physical examination, vital signs, and laboratory safety tests performed at the prestudy (screening) visit and/or prior to administration of the initial dose of study drug
• Participant has no clinically significant abnormality on electrocardiogram (ECG) performed at the prestudy (screening) visit and/or prior to administration of the initial dose of study drug
• Participants with female partner(s) of childbearing potential must agree to use a medically acceptable method of contraception during the study and for 90 days after the last dose of study drug
• Participant has a clinical diagnosis of chronic HCV infection (for Part II only).

Exclusion Criteria:

• Participant has a history of stroke, chronic seizures, or major neurological disorder
• Participant has a history of clinically significant endocrine, gastrointestinal, cardiovascular, hematological, immunological, renal, respiratory, or genitourinary abnormalities or diseases
• Participant has a history of neoplastic disease (including leukemia, lymphoma, malignant melanoma), or myeloproliferative disease, regardless of the time since treatment
• Participant has positive Hepatitis B surface antigen (or other evidence of active Hepatitis B infection) at the prescreening (study) visit
• For Healthy Panel (Part I), participant has evidence of chronic Hepatitis C virus infection at the prescreening (study) visit
• Participant has a history of documented Human Immunodeficiency Virus (HIV) infection