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Purpose: Elbasvir (MK-8742) and grazoprevir (MK-5172; Merck & Co, Inc, Kenilworth, New Jersey) are hepatitis C virus (HCV)-specific inhibitors of the nonstructural protein 5A phosphoprotein and the nonstructural protein 3/4A protease, respectively. The aims of these studies were to evaluate the antiviral activity and safety of different doses of elbasvir or grazoprevir each administered as monotherapy to participants infected with either HCV genotype (GT) 1 or GT3., Methods: These 2 double-blind, randomized, placebo-controlled, sequential-panel, multiple ascending dose studies were conducted to assess the safety and pharmacodynamics of 5 days of once-daily elbasvir or 7 days of once-daily grazoprevir in adult male participants chronically infected with either HCV GT1 or GT3., Findings: Oral administration of elbasvir or grazoprevir once daily exhibited potent antiviral activity in participants with chronic GT1 or GT3 HCV infections. HCV RNA levels declined rapidly (within 1 day for elbasvir and 2 days for grazoprevir). At 50 mg of elbasvir once daily, the mean maximum reductions in HCV RNA from baseline were 5.21, 4.17, and 3.12 log 10 IU/mL for GT1b-, GT1a-, and GT3-infected participants, respectively. At 100 mg of grazoprevir once daily, the mean maximum reductions in HCV RNA from baseline were 4.74 and 2.64 log 10 IU/mL for GT1- and GT3-infected participants., Implications: The results in the elbasvir monotherapy study showed that 10 to 50 mg of elbasvir was associated with a rapid decline in HCV viral load; the results in the grazoprevir monotherapy study suggest that doses of 50 mg of grazoprevir and higher are on the maximum response plateau of the dose-response curve for GT1-infected participants. The results of these proof-of-concept studies provided preliminary data for the selection of the dosages of elbasvir and grazoprevir to test in Phase II and III clinical studies. ClinicalTrials.gov identifiers: NCT00998985 (Protocol 5172-004) and NCT01532973 (Protocol 8742-002)., (Copyright © 2018 Elsevier HS Journals, Inc. All rights reserved.)

Background: New hepatitis C virus (HCV) therapies with pan-genotypic efficacy are needed. The goals of part A of C-CREST-1 and C-CREST-2 were to compare the efficacies of two doses (300 mg or 450 mg once daily) of uprifosbuvir (MK-3682; NS5B inhibitor) in an 8-week regimen combined with grazoprevir (NS3/4A inhibitor; 100 mg once daily) and an NS5A inhibitor, either elbasvir (50 mg once daily) or ruzasvir (MK-8408; 60 mg once daily), and to evaluate the safety and tolerability of these combination regimens in individuals infected with genotypes 1, 2, or 3., Methods: Part A of these phase 2, randomised, multicentre, open-label, clinical trials enrolled participants from 11 countries, aged 18 years or older, chronically infected with HCV genotypes 1, 2, or 3, with HCV RNA of at least 10 000 IU/mL, without evidence of cirrhosis, who had not received previous treatment for HCV infection. Within each HCV genotype, participants were randomly assigned (1:1:1:1) with a block size of 4, to open-label treatment to one of four treatment groups: grazoprevir (100 mg/day) plus ruzasvir (60 mg/day) plus uprifosbuvir (300 mg/day); grazoprevir (100 mg/day) plus ruzasvir (60 mg/day) plus uprifosbuvir (450 mg/day); grazoprevir (100 mg/day) plus elbasvir (50 mg/day) plus uprifosbuvir (300 mg/day); or grazoprevir (100 mg/day) plus elbasvir (50 mg/day) plus uprifosbuvir (450 mg/day), according to a computer-generated allocation schedule. Randomisation was centrally implemented using an interactive voice response system and integrated web response system. The primary endpoint was the proportion of participants achieving sustained virological response at 12 weeks (SVR12; HCV RNA less than the lower limit of quantitation at 12 weeks after the end of all study therapy) in the per-protocol analysis set, which included all participants who were randomised and received at least one dose of study drug. The trials are registered with ClinicalTrials.gov, numbers NCT02332707 and NCT02332720., Findings: 241 participants were randomised between Feb 18, 2015, and March 16, 2015. 240 participants completed 8 weeks of treatment and reached follow-up 12 weeks after the end of treatment. Of the four regimens, grazoprevir plus ruzasvir plus uprifosbuvir 450 mg had the most consistently high SVR12 (>90%) for participants infected with genotype 1 (21 [91%] of 23), genotype 2 (15 [94%] of 16), and genotype 3 (20 [91%] of 22). In particular, among those with genotype 2 infection, the grazoprevir plus ruzasvir plus uprifosbuvir 450 mg regimen had a higher SVR12 (15 [94%] of 16) than the grazoprevir plus ruzasvir plus uprifosbuvir 300 mg regimen (ten [71%] of 14), grazoprevir plus elbasvir plus uprifosbuvir 300 mg regimen (11 [69%] of 16), or grazoprevir plus elbasvir plus uprifosbuvir 450 mg regimen (nine [60%] of 15). Overall, the most common adverse events were headache (55 [23%] of 240), fatigue (47 [20%] of 240), and nausea (32 [13%] of 240). Two (<1%) of 240 participants had serious adverse events (pharyngeal abscess and keratitis), which were not considered drug related by the respective investigators., Interpretation: These results support further evaluation of the three-drug direct-acting antiviral agent regimen of grazoprevir 100 mg plus ruzasvir 60 mg plus uprifosbuvir 450 mg among a more diverse HCV-infected population, including those with compensated cirrhosis, previous treatment with an interferon-containing regimen, and HCV-HIV co-infection., Funding: Merck & Co, Inc., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: There is a need for hepatitis C virus (HCV) therapies with excellent efficacy across genotypes and in diverse populations. Part A of the C-CREST-1 and C-CREST-2 trials led to the selection of a three-drug regimen of grazoprevir (MK-5172; an HCV NS3/4A protease inhibitor; 100 mg/day) plus ruzasvir (MK-8408; an NS5A inhibitor; 60 mg/day) plus uprifosbuvir (MK-3682; an HCV NS5B polymerase inhibitor; 450 mg/day). Part B of the studies tested this combination as a single formulation in different treatment durations in a broader population., Methods: Part B of these randomised, phase 2, open-label clinical trials enrolled individuals from 15 countries who were chronically infected with HCV genotypes 1-6 (HCV RNA ≥10 000 IU/mL) with or without compensated cirrhosis. Those with genotype 1, genotype 2, genotype 4, or genotype 6 were treatment-naive; those with genotype 3 could be treatment-naive or treatment-experienced with pegylated interferon and ribavirin. Randomisation occurred centrally using an interactive voice response system and integrated web response system. Participants were randomly assigned to receive treatment for 8, 12, or 16 weeks with a fixed-dose combination of grazoprevir, ruzasvir, and uprifosbuvir with or without ribavirin. The primary endpoint was the proportion of participants achieving sustained virological response 12 weeks after the end of all study therapy (SVR12), defined as HCV RNA less than the lower limit of quantification (either target detected unquantifiable or target not detected [<15 IU/mL]). The trials are registered at ClinicalTrials.gov, numbers NCT02332707 and NCT02332720., Findings: 676 participants were randomly assigned between Feb 18, 2015, and Aug 16, 2016. In all 675 participants who received at least one dose of study drug (full analysis set), SVR12 for the 8-week regimen of grazoprevir, ruzasvir, and uprifosbuvir with and without ribavirin was achieved in 39 (93% [95% CI 81-99]) of 42 participants with genotype 1a, 45 (98% [88-100]) of 46 with genotype 1b, 54 (86% [75-93]) of 63 with genotype 2, 98 (95% [89-98]) of 103 with genotype 3, and seven (100% [59-100]) of seven participants with genotype 4. SVR12 for the 12-week regimen with and without ribavirin was achieved in 87 (99% [95% CI 94-100]) of 88 participants with genotype 1, 61 (98% [91-100]) of 62 with genotype 2, and four (100% [40-100]) of four with genotype 6. Among participants with cirrhosis who were infected with genotype 3, SVR12 for the 12-week regimen with and without ribavirin was achieved in 28 (97% [95% CI 82-100]) of 29 of those who were treatment-naive and 29 (100% [88-100]) of 29 who were treatment-experienced. SVR12 for the 16-week regimen with and without ribavirin was achieved in 26 (100% [95% CI 87-100]) of 26 participants with genotype 2 infection and 72 (96% [89-99]) of 75 participants with genotype 3 infection. The most common adverse events were headache (143 [22%] of 664), fatigue (129 [19%] of 664), and nausea (83 [13%] of 664). 16 (2%) of 664 participants had serious adverse events., Interpretation: The combined regimen of grazoprevir (100 mg/day), ruzasvir (60 mg/day), and uprifosbuvir (450 mg/day) has the potential to provide a simplified treatment for HCV that is effective and well tolerated in most individuals infected with HCV, as well as a shorter duration of treatment in many individuals., Funding: Merck & Co, Inc., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background & Aims: Patients infected with hepatitis C virus (HCV) genotype 1, 4, or 6, with or without cirrhosis, previously treated with peg-interferon and ribavirin, are a challenge to treat. We performed a phase 3 randomized controlled open-label trial to assess the effects of 12 or 16 weeks of treatment with once-daily elbasvir (an HCV NS5A inhibitor, 50 mg) and grazoprevir (an HCV NS3/4A protease inhibitor, 100 mg), in a fixed-dose combination tablet, with or without twice-daily ribavirin, in this patient population., Methods: We analyzed data from 420 patients (35% with cirrhosis, 64% with a null or partial response to peg-interferon and ribavirin) who were randomly assigned (1:1:1:1) to groups given elbasvir and grazoprevir once daily, with or without twice-daily ribavirin, for 12 or 16 weeks, at 65 study centers in 15 countries in Europe, Asia, and Central and North America. Randomization was stratified by cirrhosis status and type of peg-interferon and ribavirin treatment failure. HCV RNA was measured using COBAS TaqMan v2.0. The primary end point was HCV RNA <15 IU/mL, 12 weeks after completion of treatment (SVR12). We aimed to determine whether the proportion of patients achieving an SVR12 in any group was greater than the reference rate (58%)., Results: With 12 weeks of treatment, an SVR12 was achieved by 92.4% of patients given elbasvir and grazoprevir and 94.2% of patients given elbasvir and grazoprevir with ribavirin. With 16 weeks of treatment, an SVR12 was achieved by 92.4% of patients given elbasvir and grazoprevir and 98.1% of patients given elbasvir and grazoprevir with ribavirin. Among patients treated for 12 weeks without ribavirin, virologic failure occurred in 6.8%, 0%, and 12.5% of patients with HCV genotype 1a, 1b, or 4 infection, respectively. Among patients given elbasvir and grazoprevir for 12 weeks, virologic failure occurred in 0% of patients infected with HCV genotypes 1 and 4 who relapsed after completing peg-interferon and ribavirin, and 7.5% infected with HCV genotypes 1 and 4, respectively, with a null or partial response to peg-interferon and ribavirin. Among patients treated for 16 weeks who received ribavirin, there were no incidences of virologic failure. Common adverse events were fatigue (23.1%), headache (19.8%), and nausea (11.0%)., Conclusions: The combination tablet of elbasvir and grazoprevir, with or without ribavirin, was highly efficacious in inducing an SVR12 in patients with HCV genotype 1, 4, or 6 infection failed by previous treatment with peg-interferon and ribavirin, including patients with cirrhosis and/or a prior null response. The treatment was generally well tolerated. ClinicalTrials.gov Number: NCT02105701., (Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Background: Hepatitis C virus (HCV) infection is common in persons who inject drugs (PWID)., Objective: To evaluate elbasvir-grazoprevir in treating HCV infection in PWID., Design: Randomized, placebo-controlled, double-blind trial. (ClinicalTrials.gov: NCT02105688)., Setting: Australia, Canada, France, Germany, Israel, the Netherlands, New Zealand, Norway, Spain, Taiwan, the United Kingdom, and the United States., Patients: 301 treatment-naive patients with chronic HCV genotype 1, 4, or 6 infection who were at least 80% adherent to visits for opioid agonist therapy (OAT)., Intervention: The immediate-treatment group (ITG) received elbasvir-grazoprevir for 12 weeks; the deferred-treatment group (DTG) received placebo for 12 weeks, no treatment for 4 weeks, then open-label elbasvir-grazoprevir for 12 weeks., Measurements: The primary outcome was sustained virologic response at 12 weeks (SVR12), evaluated separately in the ITG and DTG. Other outcomes included SVR24, viral recurrence or reinfection, and adverse events., Results: The SVR12 was 91.5% (95% CI, 86.8% to 95.0%) in the ITG and 89.5% (95% CI, 81.5% to 94.8%) in the active phase of the DTG. Drug use at baseline and during treatment did not affect SVR12 or adherence to HCV therapy. Among 18 patients with posttreatment viral recurrence through 24-week follow-up, 6 had probable reinfection. If the probable reinfections were assumed to be responses, SVR12 was 94.0% (CI, 89.8% to 96.9%) in the ITG. One patient in the ITG (1 of 201) and 1 in the placebo-phase DTG (1 of 100) discontinued treatment because of an adverse event., Limitation: These findings may not be generalizable to PWID who are not receiving OAT, nor do they apply to persons with genotype 3 infection, a common strain in PWID., Conclusion: Patients with HCV infection who were receiving OAT and treated with elbasvir-grazoprevir had high rates of SVR12, regardless of ongoing drug use. These results support the removal of drug use as a barrier to interferon-free HCV treatment for patients receiving OAT., Primary Funding Source: Merck & Co.

Background & Aims: HCV-infected cirrhotics may urgently need therapy but are often under-represented in clinical trials resulting in limited data to guide their management. We performed a meta-analysis of well-compensated cirrhotic patients from five Phase 3 trials., Methods: Patients received P/R (peginterferon/ribavirin; 4 weeks) followed by BOC (boceprevir)/P/R or P/R for 24, 32, or 44 weeks. Sustained virologic response (SVR) rates were calculated by Metavir score. Multivariate logistic regression (MLR) models identified baseline and on-treatment predictors of SVR. Safety was evaluated by adverse-event (AE) reporting and laboratory monitoring., Results: Pooled meta-estimates for SVR rates (95% confidence interval) in 212 F4 (cirrhotic) patients were 55% (43, 66) with BOC/P/R vs.17% (0, 41) with P/R. MLR identified 4 predictors of SVR in F3/F4 patients: undetectable HCV-RNA at treatment week (TW) 8; ⩾ 1 log10 decline in HCV-RNA from baseline at TW4; male; and baseline HCV-RNA ⩽ 800,000 IU/ml. SVR rate was 89% (65/73) in F4 patients who were HCV-RNA undetectable at TW8. No F3 (0/5) or F4 (0/17) patients with <3 log10 decline and detectable HCV-RNA at TW8 achieved SVR. Anemia and diarrhea occurred more frequently in cirrhotic than non-cirrhotic patients. Serious AEs, discontinuations due to an AE, interventions to manage anemia, infections, and thrombocytopenia occurred more frequently in cirrhotics with BOC/P/R than P/R. Potential hepatic decompensation and/or sepsis were identified in 2 P/R and 3 BOC/P/R recipients., Conclusions: BOC/P/R appears to have a generally favorable benefit-risk profile in compensated cirrhotic patients. SVR rates were particularly high in cirrhotic patients with undetectable HCV-RNA at TW8., (Copyright © 2014 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

Background & Aims: Treatment of hepatitis C virus (HCV) infection with boceprevir, peginterferon, and ribavirin can lead to anemia, which has been managed by reducing ribavirin dose and/or erythropoietin therapy. We assessed the effects of these anemia management strategies on rates of sustained virologic response (SVR) and safety., Methods: Patients (n = 687) received 4 weeks of peginterferon and ribavirin followed by 24 or 44 weeks of boceprevir (800 mg, 3 times each day) plus peginterferon and ribavirin. Patients who became anemic (levels of hemoglobin approximately ≤10 g/dL) during the study treatment period (n = 500) were assigned to groups that were managed by ribavirin dosage reduction (n = 249) or erythropoietin therapy (n = 251)., Results: Rates of SVR were comparable between patients whose anemia was managed by ribavirin dosage reduction (71.5%) vs erythropoietin therapy (70.9%), regardless of the timing of the first intervention to manage anemia or the magnitude of ribavirin dosage reduction. There was a threshold for the effect on rate of SVR: patients who received <50% of the total milligrams of ribavirin assigned by the protocol had a significantly lower rate of SVR (P < .0001) than those who received ≥50%. Among patients who did not develop anemia, the rate of SVR was 40.1%. Eleven thromboembolic adverse events were reported in 9 of 295 patients who received erythropoietin, compared with 1 of 392 patients who did not receive erythropoietin., Conclusions: Reduction of ribavirin dosage can be the primary approach for management of anemia in patients receiving peginterferon, ribavirin, and boceprevir for HCV infection. Reduction in ribavirin dosage throughout the course of triple therapy does not affect rates of SVR. However, it is important that the patient receives at least 50% of the total amount (milligrams) of ribavirin assigned by response-guided therapy. ClinicalTrials.gov number, NCT01023035., (Copyright © 2013 AGA Institute. Published by Elsevier Inc. All rights reserved.)