Blood was drawn from each participant to assess Hepatitis C Virus ribonucleic acid (HCV RNA) plasma levels using the Roche COBAS® AmpliPrep/COBAS® Taqman HCV Test, v2.0, which had a lower limit of quantification (LLOQ) of 15 IU/mL. SVR12 was defined as HCV RNA below the lower limit of detection (\<LLOQ) at 12 weeks after the end of all study therapy. As pre-specified in the protocol, the Deferred Treatment Group was not included in the primary efficacy analysis.

An AE is defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment. An AE can therefore be any unfavourable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening of a pre-existing condition that is temporally associated with the use of the Sponsor's product, is also an AE. The primary safety analysis compared the safety data of the Immediate Treatment Group during the active treatment period to those of the Deferred Treatment Group during the placebo treatment period.

An AE is defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment. An AE can therefore be any unfavourable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening of a pre-existing condition that is temporally associated with the use of the Sponsor's product, is also an AE. A participant could discontinue from treatment but continue to participate in the study as long as consent was not withdrawn. The primary safety analysis compared the safety data of the Immediate Treatment Group during the active treatment period to those of the Deferred Treatment Group during the placebo treatment period.

The percentage of participants in the both arms achieving SVR12 (i.e., HCV riboncleic acid \[RNA\] level below the lower limit of quantification \[LLoQ\] 12 weeks after completing study therapy) was determined. HCV RNA levels were measured using the Roche COBAS™ Taqman™ HCV Test v2.0 (High Pure System), which has a LLoQ of \<15 IU/mL.

An AE is any untoward medical occurrence which does not necessarily have to have a causal relationship with this treatment.

An AE is any untoward medical occurrence which does not necessarily have to have a causal relationship with this treatment.

The percentage of participants achieving SVR12 (i.e., HCV ribnonucleic acid \[RNA\] \< Lower Limit of Quantification \[LLOQ\] 12 weeks after completing study treatment) was determined. Plasma HCV RNA levels were determined with the COBAS™ AmpliPrep/COBAS™ Taqman™ HCV Test, v2.0 ® assay, which has a LLOQ of 15 IU/mL.

An AE is defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment.

SVR12 is defined as HCV ribonucleic acid (RNA) less than the lower limit of quantification (\<LLOQ, 15 IU/mL) 12 weeks after the end of all study therapy. A4+B4: GT3 NC TN MK-3682B (8 weeks) arm includes both participants from Part A and Part B who received equivalent dose of MK-3682B.

An adverse event is defined as any untoward medical occurrence in a patient or clinical investigation participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment. Part C in the table below combines all (eight) participants from the four distinct arms of Part A who relapsed and were subsequently treated with MK-3682B + RBV for 16 weeks.

An adverse event is defined as any untoward medical occurrence in a patient or clinical investigation participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment. Part C in the table below combines all (eight) participants from the four distinct arms of Part A who relapsed and were subsequently treated with MK-3682B + RBV for 16 weeks.

The percentage of participants with Hepatitis C virus (HCV) ribonucleic acid (RNA) \< Lower Limit of Quantification (LLoQ) 12 weeks after completing treatment (i.e., SVR12) in each arm was determined. Plasma levels of HCV RNA levels were measured using the Roche COBAS® AmpliPrep/COBAS® TaqMan® HCV Test, v2.0 assay, which has a LLoQ of 15 IU/mL.

An AE is defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment.

Blood was drawn from each participant to assess Hepatitis C Virus ribonucleic acid (HCV RNA) plasma levels using the Roche COBAS® Taqman quantitative reverse transcription-polymerase chain reaction (RT-PCR) assay, v2.0, which had a lower limit of quantification (LLoQ) of 1.2 Log IU/mL (15 IU/mL) and a lower limit of detection (LLoD) below 15 IU/ml (no specific value). SVR12 was defined as undetectable HCV RNA (target not detected) at 12 weeks after the end of all study therapy. The Clopper-Pearson method was used to construct 95% confidence intervals (CIs) for the SVR12 rate. The lower limit of the 95% CI was compared to the reference rate of 75%; a lower CI limit that was higher than the reference rate would confirm the primary hypothesis and indicate that that the treatment combination was efficacious. As pre-specified in the protocol, only the Immediate Treatment Arm of Part 2 (treatment naïve participants) was included in the primary efficacy analysis.

An AE was defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which did not necessarily have to have a causal relationship with this treatment. An AE could therefore be any unfavourable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening (i.e., any clinically significant adverse change in frequency and/or intensity) of a preexisting condition that is temporally associated with the use of the Sponsor's product, was also an AE. The primary safety evaluation was limited to the initial treatment period through Follow-up Week 4 (FUWK4).

An AE was defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which did not necessarily have to have a causal relationship with this treatment. An AE could therefore be any unfavourable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening (i.e., any clinically significant adverse change in frequency and/or intensity) of a preexisting condition that is temporally associated with the use of the Sponsor's product, was also an AE. The primary safety evaluation was limited to the initial treatment period through FUWK4.

An AE was defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which did not necessarily have to have a causal relationship with this treatment. An AE could therefore be any unfavourable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening of a preexisting condition that is temporally associated with the use of the Sponsor's product, was also an AE. The primary safety evaluation was limited to the initial treatment period and first 4 follow-up weeks, and the primary safety statistical analysis compared the percentage of participants with events between the Part 2 Immediate Treatment Arm and the Part 2 Deferred Treatment Arm while receiving placebo.

An AE was defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which did not necessarily have to have a causal relationship with this treatment. An AE could therefore be any unfavourable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening of a preexisting condition that is temporally associated with the use of the Sponsor's product, was also an AE. The primary safety evaluation was limited to the initial treatment period and first 4 follow-up weeks, and the primary safety statistical analysis compared the percentage of participants with events between the Part 2 Immediate Treatment Arm and the Part 2 Deferred Treatment Arm while receiving placebo.

The percentage of participants achieving SVR12, defined as HCV ribonucleic acid (RNA) \<15 IU/mL 12 weeks after completing all study therapy, was determined for each arm. Plasma levels of HCV RNA were measured using the Roche COBAS© AmpliPrep/COBAS© TaqMan© HCV Test v. 2.0.

An AE is defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment.

An AE is defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment.

SVR12 was defined as Hepatitis C Virus ribonucleic acid (HCV RNA) \<25 IU/mL, either target detected but unquantifiable (TD\[u\]) or target not detected (TND), at 12 weeks after the end of all study therapy. The percentage of participants with SVR12 and accompanying 95% confidence intervals (CIs) were reported for each treatment arm in the Per-Protocol (PP) Population.

AE was defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which did not necessarily have to have a causal relationship with this treatment. An AE could therefore be any unfavorable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product/protocol-specified procedure, whether or not considered related to the medicinal product/protocol-specified procedure. Any worsening of a preexisting condition temporally associated with the use of the product was also an AE. An SAE was an AE that resulted in death, was life threatening, resulted in persistent or significant disability/incapacity, resulted in or prolonged an existing inpatient hospitalization, was a congenital anomaly/birth defect, was a cancer, was associated with an overdose, was another important medical event. The investigator determined the relationship of the AE to the treatment as unrelated or possibly, probably, or definitely related.

An AE was defined as any unfavorable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening (i.e., any clinically significant adverse change in frequency and/or intensity) of a preexisting condition which is temporally associated with the use of the SPONSOR's product, was also an AE.

An AE was defined as any unfavorable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening (i.e., any clinically significant adverse change in frequency and/or intensity) of a preexisting condition which is temporally associated with the use of the SPONSOR's product, was also an AE.

An adverse event is defined as any untoward medical occurrence in a patient or clinical investigation subject administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment. An adverse event can therefore be any unfavourable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening (i.e., any clinically significant adverse change in frequency and/or intensity) of a preexisting condition that is temporally associated with the use of the Sponsor's product, is also an adverse event. Data are presented according to actual treatment duration (12 weeks or 24 weeks) regardless of participants' initial arm assignment.

An adverse event is defined as any untoward medical occurrence in a patient or clinical investigation subject administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment. An adverse event can therefore be any unfavourable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening (i.e., any clinically significant adverse change in frequency and/or intensity) of a preexisting condition that is temporally associated with the use of the Sponsor's product, is also an adverse event. Data are presented according to actual treatment duration (12 weeks or 24 weeks) regardless of participants' initial arm assignment.

Each participant was assigned to undergo Fine Needle Aspiration (FNA) to obtain liver tissue at different time points. Specifically, one participant underwent FNA at 4 hr post-dose only, another participant underwent FNA at 8 hr post-dose only, and a third participant underwent FNA at 24 hr post-dose only. (The fourth participant underwent FNA at 72 hr post-dose and therefore was not included in the calculation of AUC0-24hr.) Therefore, in calculating AUC0-24hr, there were only 3 data points: 1 data point at 4 hr post-dose, 1 data point at 8 hr post-dose, and 1 data point at 24 hr post-dose. The model assumed that drug concentration was at steady-state, and that the concentration at 24 hr post-dose was equal to the concentration at 0 hr post-dose.

C(H)Xhr of GZR was expressed as liver concentration (μmol GZR/L liver) using the concentration of the extracted liver sample (mass of the liver biopsy/0.2 mL solvent), and assuming that liver has the specific gravity of water (1 g/mL). The arithmetic mean C(H)Xhr concentration is based on the means of 4 FNA passes per participant in all 4 participants.

t(H)1/2 is a measure of the time required for the maximum post-dose liver concentration of GZR to decrease by 50%.

Blood samples were collected at pre-dose, and from 0.5 to 24 hours post-dose on Days 1 and 10 in order to determine the plasma AUC0-24 of Grazoprevir. Classification of HI based on the Child-Pugh scale, where a score of 5-6 = Mild HI; a score of 7-9 = Moderate HI; and a score of 10-15 = Severe HI.

Blood samples were collected at pre-dose, and from 0.5 to 24 hours post-dose on Days 1 and 10 in order to determine the plasma Cmax of Grazoprevir. Classification of HI based on the Child-Pugh scale, where a score of 5-6 = Mild HI; a score of 7-9 = Moderate HI; and a score of 10-15 = Severe HI.

Blood samples were collected at pre-dose, and from 0.5 to 24 hours post-dose on Days 1 and 10 in order to determine the plasma Tmax of Grazoprevir. Classification of HI based on the Child-Pugh scale, where a score of 5-6 = Mild HI; a score of 7-9 = Moderate HI; and a score of 10-15 = Severe HI.

Blood samples were collected at 24 hours post-dose on Day 1 in order to determine the plasma C24 of Grazoprevir. Classification of HI based on the Child-Pugh scale, where a score of 5-6 = Mild HI; a score of 7-9 = Moderate HI; and a score of 10-15 = Severe HI.

Blood samples were collected at 24 hours post-dose on Day 1 in order to determine the plasma C24 of Grazoprevir. Classification of HI based on the Child-Pugh scale, where a score of 5-6 = Mild HI; a score of 7-9 = Moderate HI; and a score of 10-15 = Severe HI.

Blood samples were collected at 24 hours post-dose on Day 10 in order to determine the plasma C24 of Grazoprevir. Classification of HI based on the Child-Pugh scale, where a score of 5-6 = Mild HI; a score of 7-9 = Moderate HI; and a score of 10-15 = Severe HI.

Blood samples were collected at pre-dose, and from 0.5 to 24 hours post-dose on Day 10 in order to determine the plasma t1/2 of Grazoprevir. Classification of HI based on the Child-Pugh scale, where a score of 5-6 = Mild HI; a score of 7-9 = Moderate HI; and a score of 10-15 = Severe HI.

An AE is any unfavorable and unintended change in the structure, function, or chemistry of the body temporally associated with the use of the SPONSOR's product, whether or not considered related to the use of the product. Any worsening (i.e., any clinically significant adverse change in frequency and/or intensity) of a preexisting condition which is temporally associated with the use of the SPONSOR's product, is also an AE.