| E.1 Medical condition or disease under investigation | 
| E.1.1 | Medical condition(s) being investigated |  | 
| E.1.1.1 | Medical condition in easily understood language | 
| A viral infection affecting the liver |  | 
| E.1.1.2 | Therapeutic area | Diseases [C] - Virus Diseases [C02] | 
| MedDRA Classification | 
| E.1.3 | Condition being studied is a rare disease | No | 
| E.2 Objective of the trial | 
| E.2.1 | Main objective of the trial | 
| •To evaluate the efficacy of MK-5172 in combination with MK-8742 as assessed by the proportion of subjects achieving SVR12 (Sustained Virologic Response 12 weeks after the end of all study therapy), defined as HCV RNA <LLOQ (either TD[u] or TND) 12 weeks after the end of all study therapy. •To evaluate the safety and tolerability of MK-5172 in combination with MK-8742.
 
 |  | 
| E.2.2 | Secondary objectives of the trial | 
| Part A 1) To evaluate the efficacy of MK-5172 in combination with MK-8742 as assessed by the proportion of subjects achieving: SVR24 (Sustained Virologic Response 24 weeks after the end of all study therapy), defined as HCV RNA <LLOQ (either TD(u) or TND) 24 weeks after the end of all study therapy.
 
 Part B
 1) To evaluate the durability of SVR and the incidence of detectable HCV
 RNA, classified as either relapse or reinfection, over a three year follow-up period
 following the treatment/follow-up as defined in Part A .
 2) To characterize the HCV virus detected during the Part A treatment and
 follow-up periods and as well as in the Part B 3-year follow-up period including:
 a. To describe the presence of baseline viral resistance-associated variants
 (RAVs)
 b. To describe treatment emergent RAVs
 c. To determine reinfection versus relapse
 |  | 
| E.2.3 | Trial contains a sub-study | No | 
| E.3 | Principal inclusion criteria | 
| Part A: •You are greater than or equal to 18 years of age.
 •You have chronic genotype 1, 4, 5, or 6 Hepatitis C virus.
 •You must be on opiate substitution therapy (OST), have kept at least 80% of scheduled appointments while on OST, and not missed any scheduled appointments between screening and study entry
 •You have had a liver biopsy, Fibroscan, or Fibrotest to check for cirrhosis or no cirrhosis.
 •You are treatment naïve to all HCV treatment
 •You may be co-infected with HIV
 
 Part B:
 - You have received at least one dose of MK-5172 in combination with MK-8742 as detailed in
 Part A.
 - You understand the study procedures, alternative treatments available, risks involved with the
 study, and voluntarily agree to participate by giving written informed consent.
 |  | 
| E.4 | Principal exclusion criteria | 
| Part A: •You have signs of decompensated liver disease.
 •You are coinfected with Hepatitis B virus.
 •You have signs of hepatocellular carcinoma or history of malignancy.
 •You are taking or plan to take any medication not allowed for this study.
 •You have a history of, or signs of, chronic hepatitis not caused by hepatitis C virus.
 •You have an exclusionary laboratory value
 •If you have HIV, you use HIV drugs other than a dual NRTI backbone of tenofovir or abacavir and either emtricitabine or lamivudine PLUS raltegravir [or dolutegravir or rilpivine]
 •You have a history of opportunistic infection in the preceding 6 months prior to screening.
 
 Part B:
 - You are mentally or legally incapacitated, have significant emotional problems at the time of
 pre-study screening visit or expected during the conduct of the study or have a history
 of a clinically significant psychiatric disorder which, in the opinion of the
 investigator, would interfere with the study procedures.
 - You have a medical condition or personal circumstance which, in the opinion of
 the investigator and/or Sponsor, places you at unnecessary risk through
 continued participation in the trial or does not allow you to adhere to the
 requirements of the protocol.
 
 |  | 
| E.5 End points | 
| E.5.1 | Primary end point(s) | 
| The SVR12 rate of subjects enrolled. |  | 
| E.5.1.1 | Timepoint(s) of evaluation of this end point |  | 
| E.5.2 | Secondary end point(s) | 
| Part A: The SVR24 rate of subjects enrolled. Part B: primary measurement is plasma HCV RNA, collected every 6 months to evaluate long term durability of SVR and incidence of reinfection in subjects with detectable HCV RNA.
 |  | 
| E.5.2.1 | Timepoint(s) of evaluation of this end point |  | 
| E.6 and E.7 Scope of the trial | 
| E.6 | Scope of the trial | 
| E.6.1 | Diagnosis | No | 
| E.6.2 | Prophylaxis | No | 
| E.6.3 | Therapy | No | 
| E.6.4 | Safety | Yes | 
| E.6.5 | Efficacy | Yes | 
| E.6.6 | Pharmacokinetic | Yes | 
| E.6.7 | Pharmacodynamic | Yes | 
| E.6.8 | Bioequivalence | No | 
| E.6.9 | Dose response | No | 
| E.6.10 | Pharmacogenetic | No | 
| E.6.11 | Pharmacogenomic | Yes | 
| E.6.12 | Pharmacoeconomic | No | 
| E.6.13 | Others | No | 
| E.7 | Trial type and phase | 
| E.7.1 | Human pharmacology (Phase I) | No | 
| E.7.1.1 | First administration to humans | No | 
| E.7.1.2 | Bioequivalence study | No | 
| E.7.1.3 | Other | No | 
| E.7.1.3.1 | Other trial type description |  | 
| E.7.2 | Therapeutic exploratory (Phase II) | No | 
| E.7.3 | Therapeutic confirmatory (Phase III) | Yes | 
| E.7.4 | Therapeutic use (Phase IV) | No | 
| E.8 Design of the trial | 
| E.8.1 | Controlled | Yes | 
| E.8.1.1 | Randomised | Yes | 
| E.8.1.2 | Open | No | 
| E.8.1.3 | Single blind | No | 
| E.8.1.4 | Double blind | Yes | 
| E.8.1.5 | Parallel group | No | 
| E.8.1.6 | Cross over | No | 
| E.8.1.7 | Other | No | 
| E.8.2 | Comparator of controlled trial | 
| E.8.2.1 | Other medicinal product(s) | No | 
| E.8.2.2 | Placebo | Yes | 
| E.8.2.3 | Other | No | 
| E.8.2.4 | Number of treatment arms in the trial | 2 | 
| E.8.3 | The trial involves single site in the Member State concerned | Yes | 
| E.8.4 | The trial involves multiple sites in the Member State concerned | No | 
| E.8.5 | The trial involves multiple Member States | Yes | 
| E.8.5.1 | Number of sites anticipated in the EEA | 19 | 
| E.8.6 Trial involving sites outside the EEA | 
| E.8.6.1 | Trial being conducted both within and outside the EEA | Yes | 
| E.8.6.2 | Trial being conducted completely outside of the EEA | No | 
| E.8.6.3 | If E.8.6.1 or E.8.6.2 are Yes, specify the regions in which trial sites are planned | 
| Australia |  
| Belgium |  
| Canada |  
| France |  
| Germany |  
| Greece |  
| Ireland |  
| Israel |  
| Italy |  
| Lithuania |  
| Malaysia |  
| Netherlands |  
| New Zealand |  
| Norway |  
| Romania |  
| Spain |  
| Taiwan |  
| United Kingdom |  
| United States |  | 
| E.8.7 | Trial has a data monitoring committee | No | 
| E.8.8 | Definition of the end of the trial and justification where it is not the last
                        visit of the last subject undergoing the trial |  | 
| E.8.9 Initial estimate of the duration of the trial | 
| E.8.9.1 | In the Member State concerned years | 4 | 
| E.8.9.1 | In the Member State concerned months | 3 | 
| E.8.9.1 | In the Member State concerned days |  | 
| E.8.9.2 | In all countries concerned by the trial years | 4 | 
| E.8.9.2 | In all countries concerned by the trial months | 3 |