Safety and efficacy of a fixed-dose combination regimen of grazoprevir, ruzasvir, and uprifosbuvir with or without ribavirin in participants with and without cirrhosis with chronic hepatitis C virus genotype 1, 2, or 3 infection (C-CREST-1 and C-CREST-2, part B): two randomised, phase 2, open-label trials

Genotype 3-hepatitis C virus’ last line of defense

Chronic infection with hepatitis C virus (HCV) is one of the leading causes of liver disease globally, affecting approximately 71 million people. The majority of them are infected with genotype (GT) 1 but infections with GT3 are second in frequency. For many years, GT3 was considered to be less pathogenic compared to other GTs in the HCV family due to its favorable response to interferon (IFN)-based regimen. However, the growing evidence of a higher rate of steatosis, more rapid progression of liver fibrosis, and lower efficacy of antiviral treatment compared to infection with other HCV GTs has changed this conviction. This review presents the specifics of the course of GT3 infection and the development of therapeutic options for GT3-infected patients in the era of direct-acting antivirals (DAA). The way from a standard of care therapy with pegylated IFN-alpha (pegIFNα) and ribavirin (RBV) through a triple combination of pegIFNα + RBV and DAA to the highly potent IFN-free pangenotypic DAA regimens is discussed along with some treatment options which appeared to be dead ends. Although the implementation of highly effective pangenotypic regimens is the most recent stage of revolution in the treatment of GT3 infection, there is still room for improvement, especially in patients with liver cirrhosis and those who fail to respond to DAA therapies, particularly those containing inhibitors of HCV nonstructural protein 5A.

Daclatasvir, sofosbuvir with or without ribavirin for 24 weeks in hepatitis C genotype 3 cirrhosis: A real-life study

INTRODUCTION AND AIM

Cirrhotic patients with hepatitis C virus genotype 3 infection show unsatisfactory outcomes after 12 weeks' treatment with direct antiviral agents. The National Italian Drug Agency allows 24 weeks of therapy in difficult-to-treat patients, including genotype 3 cirrhotics. Aim of this study was to evaluate efficacy and safety of a 24-week course of sofosbuvir plus daclatasvir±ribavirin in this population.

MATERIALS AND METHODS

106 consecutive cirrhotics (70.8% males, mean age 55.3±7.6 years) in 8 tertiary hepatology centers received sofosbuvir plus daclatasvir for 24 weeks. Ribavirin was administered in 85 (80.2%) based expected tolerability, at a mean dose of 964±202mg/day. Baseline Child-Pugh class was A 91.5%, B 6.6%, C 1.9%; mean baseline MELD was 8.5±2.7.

RESULTS

All patients completed 12-week follow-up post-treatment, and 104 (98.1%) obtained sustained virological response (100% in ribavirin -treated patients vs. 90.4% without ribavirin; p=0.04). No worsening in renal and liver function was observed, no serious adverse events occurred. Two virological failures showed resistance associated variants (Y93H and S282T).

CONCLUSION

An extended 24-week treatment with sofosbuvir plus daclatasvir+ribavirin obtained 100% efficacy in genotype 3 hepatitis C cirrhosis, with very limited side effects. The role of ribavirin seems crucial in this setting and should be administered if clinically feasible.

Sustained virologic response to direct-acting antiviral therapy in patients with chronic hepatitis C and hepatocellular carcinoma: A systematic review and meta-analysis

BACKGROUND & AIMS

The effect of hepatocellular carcinoma (HCC) on the response to interferon-free direct-acting antiviral (DAA) therapy in patients with chronic hepatitis C (CHC) infection remains unclear. Using a systematic review and meta-analysis approach, we aimed to investigate the effect of DAA therapy on sustained virologic response (SVR) among patients with CHC and either active, inactive or no HCC.

METHODS

PubMed, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials were searched from 1/1/2013 to 9/24/2018. The pooled SVR rates were computed using DerSimonian-Laird random-effects models.

RESULTS

We included 49 studies from 15 countries, comprised of 3,341 patients with HCC and 35,701 without HCC. Overall, the pooled SVR was lower in patients with HCC than in those without HCC (89.6%, 95% CI 86.8-92.1%, I² = 79.1% vs. 93.3%, 95% CI 91.9-94.7%, I² = 95.0%, p = 0.0012), translating to a 4.8% (95% CI 0.2-7.4%) SVR reduction by meta-regression analysis. The largest SVR reduction (18.8%) occurred in patients with active/residual HCC vs. inactive/ablated HCC (SVR 73.1% vs. 92.6%, p = 0.002). Meanwhile, patients with HCC who received a prior liver transplant had higher SVR rates than those who did not (p <0.001). Regarding specific DAA regimens, patients with HCC treated with ledipasvir/sofosbuvir had lower SVR rates than patients without HCC (92.6%, n = 884 vs. 97.8%, n = 13,141, p = 0.026), but heterogeneity was high (I² = 84.7%, p <0.001). The SVR rate was similar in patients with/without HCC who were treated with ombitasvir/paritaprevir/ritonavir ± dasabuvir (n = 101) (97.2% vs. 94.8%, p = 0.79), or daclatasvir/asunaprevir (91.7% vs. 89.8%, p = 0.66).

CONCLUSION

Overall, SVR rates were lower in patients with HCC, especially with active HCC, compared to those without HCC, though heterogeneity was high. Continued efforts are needed to aggressively screen, diagnose, and treat HCC to ensure higher CHC cure rates.

LAY SUMMARY

There are now medications (direct-acting antivirals or "DAAs") that can "cure" hepatitis C virus, but patients with hepatitis C and liver cancer may be less likely to achieve cure than those without liver cancer. However, patients with liver cancer are also more likely to have advanced liver disease and risk factors that can decrease cure rates, so better controlled studies are needed to confirm these findings.

Efficacy and safety of a two-drug direct-acting antiviral agent regimen ruzasvir 180 mg and uprifosbuvir 450 mg for 12 weeks in adults with chronic hepatitis C virus genotype 1, 2, 3, 4, 5 or 6

Ruzasvir (MK-8408, an NS5A inhibitor) and uprifosbuvir (MK-3682, a nonstructural protein 5B nucleotide inhibitor) are highly potent direct-acting antiviral agents for the treatment of hepatitis C virus (HCV) infection. A phase III clinical trial evaluating the two-drug combination of ruzasvir 60 mg plus  uprifosbuvir 450 mg suggested suboptimal efficacy in certain HCV genotypes (C-BREEZE 1; NCT02759315). The aim of the present study was to evaluate the efficacy and safety of ruzasvir in combination with uprifosbuvir administered at a higher dose than that assessed in the earlier study (C-BREEZE 2: NCT02956629/Merck protocol PN041). Treatment-naïve or interferon (with or without ribavirin)-experienced participants with or without compensated cirrhosis were enrolled. All participants received ruzasvir 180 mg plus uprifosbuvir 450 mg once daily for 12 weeks. The primary objectives were the proportion of participants with HCV RNA <15 lU/mL at 12 weeks after the end of study therapy (SVR12), and safety and tolerability of the study drug. Overall, 282 participants were enrolled. SVR12 (n/N) was 91.3% (42/46) in participants infected with HCV genotype (GT) 1a; GT1b, 96.7% (29/30); GT2, 91.5% (43/47); GT3, 73.8% (45/61); GT4, 98.2% (55/56); GT5, 100.0% (18/18); and GT6, 90.9% (20/22). Adverse events (AEs) were reported by 61.3% of participants; drug-related AEs were reported by 33.3%. The most frequent (≥5% of participants) drug-related AEs in all participants were fatigue (7.8%) and headache (7.4%). In conclusion, the two-drug combination of ruzasvir 180 mg plus uprifosbuvir 450 mg for 12 weeks was highly effective and well tolerated in participants infected with HCV GT1, GT2, GT4, GT5 and GT6, with a lower efficacy in GT3-infected persons.

Efficacy and safety of ruzasvir 60 mg and uprifosbuvir 450 mg for 12 weeks in adults with chronic hepatitis C virus genotype 1, 2, 3, 4 or 6 infection

In clinical trials, the three-drug regimen of ruzasvir (RZR) 60 mg, uprifosbuvir (UPR) 450 mg and grazoprevir 100 mg, with or without ribavirin, has demonstrated promising efficacy and excellent tolerability across a wide range of hepatitis C virus (HCV)-infected individuals. The present study assessed the efficacy and safety of the two-drug combination of RZR 60 mg plus UPR 450 mg administered for 12 weeks in participants with HCV genotype (GT) 1-6 infection. In this open-label clinical trial, treatment-naive or -experienced and cirrhotic or noncirrhotic participants with chronic HCV GT1-6 infection received RZR 60 mg plus UPR 450 mg orally once daily for 12 weeks (NCT02759315/protocol PN035). The primary efficacy endpoint was sustained virologic response at 12 weeks after the end of therapy (SVR12). One hundred and sixty participants were enrolled. SVR12 rates were 96% (52 of 54) in participants with GT1a infection; 100% (15 of 15) in those with GT1b infection; 97% (28 of 29) in those with GT2 infection; 77% (30 of 39) in those with GT3 infection; 90% (18 of 20) in those with GT4 infection; and 67% (2 of 3) in those with GT6 infection. Drug-related adverse events (AEs) reported by >5% of participants were fatigue (n = 10, 6.3%) and diarrhoea (n = 9, 5.6%). Five participants reported a total of 11 serious AEs, none considered drug-related. One participant experienced on-treatment alanine aminotransferase/aspartate aminotransferase elevations that resolved without intervention. Data from the present study indicate that the combination of RZR 60 mg plus UPR 450 mg once daily for 12 weeks was well tolerated overall but was effective only for certain genotypes.

Efficacy and safety of direct-acting antiviral therapy for chronic hepatitis C genotype 6: A meta-analysis

BACKGROUND

Because of the heterogeneity of hepatitis C virus (HCV) distribution of different genotypes, large-scale clinical trials on direct-acting antiviral (DAA) mainly included patients with genotype 1 and genotype 3 infection. Data on the efficacy of direct-acting antiviral agents in patients with chronic genotype 6 HCV infection are limited.

METHODS

The PubMed, Embase, and the Cochrane Libraries were searched comprehensively. All published clinical trials assessing the efficacy of DAA therapy for patients with chronic genotype 6 HCV infection were included. Sustained virological response (SVR) and rapid virological response (RVR) were pooled. Additional meta-analyses were also performed to compare the efficacy of DAA therapy in HCV-6 versus HCV-1 or HCV-3 patients.

RESULTS

Seventeen studies met the inclusion criteria and were included in our meta-analysis. The pooled SVR of all single arms was 95% [95% confidence interval (CI): 0.90-0.97]. The pooled RVR of all single arms was 97% (95% CI: 0.95-0.99). The SVR and RVR were both similar between HCV-6 and HCV-1 or HCV-3. Adverse events were common but rarely caused treatment interruption.

CONCLUSION

Based on the available data, our results indicate that DAA treatment is effective and safe for patients with genotype 6 HCV infection, and the efficacy was similar compared to patients with genotype 1 HCV or genotype 3 HCV infection.

Targeting HCV polymerase: a structural and dynamic perspective into the mechanism of selective covalent inhibition

Background: Concerns have been raised over the emerging pandemic status of hepatitis C virus (HCV). Current available drugs lack specificity, stability and potency. The HCV NS5B RNA-dependent RNA polymerase (RdRp) is a vital component in viral replication and is often targeted in antiviral therapies. Recent experimental procedures have led to the discovery of a novel covalent RdRp inhibitor, compound 47, which selectively targets cysteine 366 of the HCV RdRp and exhibits promising pharmacokinetic outcomes. Selective covalent inhibition of HCV is, however, a highly neglected subject in the literature, that is reinforced by the lack of efficient structure-based drug design protocols. In this paper, an atomistic insight into a novel selective approach to inhibit HCV RdRp is provided. Methodology/Results: Covalent molecular dynamic analyses revealed the inhibitory mechanism of compound 47 on the RdRp. Inhibitor binding induced distinctive internal movements resulting in the disruption of normal physiological interdomain interactions. Conclusion: Compound 47 stimulates reorganization of key protein elements required for RNA transcription, thus hampering viral replication as well as disrupting the overall conformation of HCV. This study will open new lines of approach for the design of novel selective inhibitors against HCV as well as other viral families.

Hepatitis C virus genotype 3: clinical features, current and emerging viral inhibitors, future challenges

Hepatitis C virus (HCV) represents a global burden on healthcare that affects over 150 million people worldwide. In the past, HCV genotype 3 was considered difficult to treat relative to other genotypes. Genotype 3 has been associated with a higher rate of complications, including fatty liver disease, fibrosis, hepatocellular carcinoma and mortality. However, with the advent of first- and second-generation direct-acting antivirals, genotype 3 can be treated effectively. Additionally, these new drugs are well tolerated by patients and have significantly fewer side effects compared to ribavirin and interferon-based regimens. However, while great strides have been made in overcoming biological barriers, our next challenge lies in overcoming economic and financial obstacles if we are to eradicate HCV genotype 3. Herein, we review the clinical features associated with HCV genotype 3, current and emerging treatment regimens, and challenges associated with treatment.

Effectiveness of current and future regimens for treating genotype 3 hepatitis C virus infection: a large-scale systematic review

BACKGROUND

Six distinct genetic variants (genotypes 1 - 6) of hepatitis C virus (HCV) exist globally. Certain genotypes are more prevalent in particular countries or regions than in others but, globally, genotype 3 (GT3) is the second most common. Patients infected with HCV GT1, 2, 4, 5 or 6 recover to a greater extent, as measured by sustained virological response (SVR), following treatment with regimens based on direct-acting antivirals (DAAs) than after treatment with older regimens based on pegylated interferon (Peg-IFN). GT3, however, is regarded as being more difficult to treat as it is a relatively aggressive genotype, associated with greater liver damage and cancer risk; some subgroups of patients with GT3 infection are less responsive to current licensed DAA treatments. Newer DAAs have become available or are in development.

METHODS

According to PRISMA guidance, we conducted a systematic review (and descriptive statistical analysis) of data in the public domain from relevant clinical trial or observational (real-world) study publications within a 5-year period (February 2011 to May 2016) identified by PubMed, Medline In-Process, and Embase searches. This was supplemented with a search of five non-indexed literature sources, comprising annual conferences of the AASLD, APASL, CROI, EASL, and WHO, restricted to a 1-year period (April 2015 to May 2016).

RESULTS

Of the all-oral regimens, the efficacy (SVR12 ≥ 90%) of sofosbuvir plus daclatasvir- and velpatasvir-based regimens in clinical trials supports and reinforces their recommendation by guidelines. Other promising regimens comprise grazoprevir + elbasvir + sofosbuvir, and ombitasvir + paritaprevir/ribavirin + sofosbuvir. Newer regimens incorporating pibrentasvir + glecaprevir or grazoprevir + ruzasvir + MK-3682 (uprifosbuvir), offer all-oral, ribavirin-free SVR12 rates consistently greater than 95%. Observational studies report slightly lower overall SVR rates but reflect corresponding clinical trial data in terms of treatments most likely to achieve good responses.

CONCLUSIONS

On the basis of SVR12, we established that for treating GT3 infections (i) regimens incorporating newer DAAs are more effective than those comprising older DAAs, and (ii) ribavirin may be of less benefit in newer DAA regimens than in older DAA regimens. The analysis provides evidence that DAA regimens can replace Peg-IFN-based regimens for GT3 infection.

Shortening the duration of therapy for chronic hepatitis C infection

Combination direct-acting antiviral therapy of 8-24 weeks is highly effective for the treatment of chronic hepatitis C infection. However, shortening the treatment duration to less than 8 weeks could potentially reduce overall treatment costs and improve adherence. Here we explore the arguments for and against the development of short-duration regimens and existing data on treatment for 6 weeks or less among patients with chronic hepatitis C virus genotype 1 infection. Additionally, we identify potential predictors of response to short-course combination therapies with direct-acting antiviral drugs that might be explored in future clinical trials.