The objective of this study is to identify a safe dose of MK-2248 in participants with Hepatitis C Virus (HCV) that mediates at least a 3 log10 reduction in viral load (VL) from baseline. It is anticipated that once-daily administration of a safe and well tolerated dose of MK-2248 will reduce VL by at least 3 log10 IU/mL.

In this Phase 1b study, the pharmacokinetic (PK), pharmacodynamic (PD), and safety profile of MK-2248 in HCV-infected participants will be evaluated as follows: Part I will assess sequentially ascending MK-2248 doses from 200 mg to ≤800 mg over 4 panels (A, B, C, and D). Part II will assess sequentially ascending MK-2248 doses from 200 mg to ≤800 mg over 4 panels (E, F, G, and H). Part III will assess sequentially ascending MK-2248 doses ranging up to ≤800 mg in 2 panels (I and J). The potential relationship between plasma MK-2248 levels and VL reduction will be determined.

Inclusion Criteria:

• clinical diagnosis of chronic HCV defined by positive serology for HCV or positive HCV RNA for at least 6 months and detectable HCV RNA in peripheral blood ≥10^5 IU/mL at screening
• Body Mass Index (BMI) ≥18 to <37 kg/m^2
• in good health other than HCV infection with normal laboratory values

Exclusion Criteria:

• history of clinically significant and not stably controlled endocrine, gastrointestinal, cardiovascular, hematological, hepatic (excepting HCV infection), immunological, renal, respiratory, genitourinary, or major neurological abnormalities or disease
• history of cancer other than adequately treated non-melanomatous skin carcinoma, malignancies which have been successfully treated ≥10 years prior with no recurrence, or cancer that is unlikely to sustain a recurrence for the duration of the trial
• history of significant multiple and/or severe allergies or has had an anaphylactic reaction or significant intolerability to prescription or non-prescription drugs or food
• positive for hepatitis B surface antigen or human immunodeficiency virus
• had major surgery or lost 1 unit of blood within 4 weeks prior to screening
• QTc interval ≥470 msec (males) or ≥480 msec (females)
• received prior treatment with other HCV inhibitors
• clinical or laboratory evidence of decompensated liver disease