Conditions: Hepatitis C
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 399
Healthy volunteers: no

Brief summary:
This is a two-part study of grazoprevir (MK-5172) + elbasvir (MK-8742) in Japanese participants with chronic hepatitis C virus (HCV) genotype 1 (GT1). Part I is a dose-finding study; in Part II, participants will be randomly assigned to receive grazoprevir at the dose determined in Part I in combination with elbasvir. The primary study hypothesis is that the percentage of treatment-naïve participants in the Immediate Treatment Arm of Part II who achieve sustained viral response at 12 weeks after the end of all treatment (SVR12) will be greater than the reference rate of 75%. A separate study arm for cirrhotic participants will also be included in Part II; these participants will receive grazoprevir at the determined dose in combination with elbasvir.

Detailed description:
In Part 1, HCV GT1 participants are randomized into one of two arms: 50 mg grazoprevir plus 50 mg elbasvir for 12 weeks during the double blinded (DB) period followed by 24 weeks of follow-up (FU) during an open-label (OL) period \[Arm 1\]; or 100 mg grazoprevir plus 50 mg elbasvir for 12 weeks during the DB followed by 24 weeks of FU during the OL \[Arm 2\]. Unblinding will occur after all participants complete FU Week 4 at which time the grazoprevir dose will be selected.

In Part 2, non-cirrhotic HCV GT1 participants and GT1 participants with compensated liver cirrhosis all receive the selected dose of grazoprevir (50 mg or 100 mg from Part 1) with 50 mg elbasvir for 12 weeks. Non-cirrhotic GT1 participants are randomized to receive either a) 12 weeks of active treatment immediately during the DB with 24 weeks of FU in the OL \[Arm 1/Immediate Arm\] or b) placebo for 12 weeks with 4 weeks of follow-up during the DB followed by 12 weeks of active treatment and 24 weeks of follow-up during the OL \[Arm 2/Deferred Arm\]. All cirrhotic participants \[Arm 3/Cirrhotic\] receive the selected dose immediately for 12 weeks during the DB with 24 weeks of FU during the OL.

Safety analyses for Part 1 and Part 2 arms will focus on the 12 week treatment phase plus the first 4 FU weeks. For the Part 2 Deferred Arm this will include the initial 12 week placebo treatment and first 4 weeks of FU. Efficacy analyses for Parts 1 and 2 will evaluate active treatment only (Weeks 1-12 for all arms except for Part 2 Deferred Arm which is weeks 16-28).

Part 1:

50 mg grazoprevir + 50 mg elbasvir treatment for 12 weeks, 24 weeks follow-up (Arm 1) 100 mg grazoprevir + 50 mg elbasvir treatment for 12 weeks, 24 weeks follow-up (Arm 2)

Part 2:

Selected dose of grazoprevir + 50 mg elbasvir treatment for 12 weeks, 24 weeks follow-up (Arm 1/Immediate) Placebo treatment for 12 weeks, 4 weeks follow-up, selected dose of grazoprevir + 50 mg elbasvir treatment for 12 weeks, 24 weeks follow-up (Arm 2/Deferred) Selected dose of grazoprevir + 50 mg elbasvir treatment for 12 weeks, 24 weeks follow-up (Arm 3/Cirrhotic)

Arms:
arm 1: Non-cirrhotic participants take 50 mg grazoprevir in combination with 50 mg elbasvir by mouth (p.o.) once daily (q.d.) for 12 weeks during the blinded period of Part 1 and are followed-up for 24 weeks during the open-label period of Part 1. arm 2: Non-cirrhotic participants take 100 mg grazoprevir in combination with 50 mg elbasvir p.o. q.d. for 12 weeks during the blinded period of Part 1 and are followed-up for 24 weeks during the open-label period of Part 1. arm 3: Non-cirrhotic participants take grazoprevir (50 mg or 100 mg dose selected from Part I) and 50 mg elbasvir p.o. q.d. for 12 weeks during the blinded period of Part 2 and are followed-up for 24 weeks during the open-label period of Part 2. arm 4: Non-cirrhotic participants take dose-matched placebo p.o. q.d. for 12 weeks during the blinded period of Part 2 followed by a 4-week follow-up. Afterwards, participants take grazoprevir (50 mg or 100 mg dose selected from Part I) and 50 mg elbasvir p.o. q.d. for 12 weeks and are followed-up for 24 weeks during the open-label period of Part 2. arm 5: Cirrhotic participants take grazoprevir (50 mg or 100 mg dose selected from Part 1) and 50 mg elbasvir p.o. q.d. for 12 weeks during the blinded period of Part 2, and are followed-up for 24 weeks during the open-label period of Part 2.

Interventions: intervention 1: Grazoprevir intervention 2: Elbasvir intervention 3: Placebo to Grazoprevir intervention 4: Placebo to Elbasvir
Intervention descriptions: intervention 1: One or two 50 mg tablets (depending on randomization) taken orally once daily for 12 weeks. intervention 2: One 50 mg tablet taken orally once daily for 12 weeks. intervention 3: One tablet of placebo matched to grazoprevir, taken orally once daily for 12 weeks. intervention 4: One tablet of placebo matched to elbasvir, taken orally once daily for 12 weeks.

Protocol document: