A randomized trial of daclatasvir in combination with asunaprevir and beclabuvir in patients with chronic hepatitis C virus genotype 4 infection

Real Life Egyptian Experience of Daclatasvir Plus Sofosbuvir with Ribavirin in Naïve Difficult to Treat HCV Patients

BACKGROUND

Chronic infection with Hepatitis C virus (HCV) is considered as a major cause for developing liver cirrhosis and hepatocellular carcinoma. A new era in HCV treatment is ongoing using Direct Acting Antiviral activity (DAA). The first approved DAA drug was Sofosbuvir which has a high tolerability and preferable pharmacokinetic profile. Another recently developed drug is Daclatasvir a first-in-class HCV NS5A replication complex inhibitor. Both drugs are administered orally once daily and have potent antiviral activity with wide genotypic coverage.

METHODS

In the outpatient clinic, one hundred and fifty naïve difficult to treat chronic HCV patients were recruited from Tropical Medicine Department at Fayoum public hospital. A combination of Daclatasvir (60 mg) and Sofosbuvir (400 mg) (DCV/SOF) has been administered for those patients once daily with Ribavirin (1200 mg or 1000 mg based on patients' weight on two divided doses) over a period of 12 weeks. All patients have been followed up for clinical, laboratory assessment and HCV PCR to detect the efficacy and safety of the therapy.

RESULTS

Sustained Virologic Response rate (SVR12) was achieved in the vast majority of patients (90.67%). Cirrhotic patients showed lower SVR compared to non-cirrhotic patients (88.89% vs 90.91%, respectively). Around half of the patients (49.33%) developed adverse events (AEs) during treatment. The most common AEs were headache, fatigue and abdominal pain.

CONCLUSION

The available evidence seems to suggest that combination therapy of (DCV/SOF with RBV) in the treatment of chronic HCV genotype IV naïve difficult to treat patients either cirrhotic or non-cirrhotic is safe and effective. Monitoring for clinical and laboratory hepatic parameters was the basis for these findings.

Efficacy and safety of a fixed dose combination tablet of asunaprevir + beclabuvir + daclatasvir for the treatment of Hepatitis C

Introduction: Hepatitis C virus (HCV) is estimated to infect approximately 70 million people worldwide. If left untreated, chronic infection can progress to cirrhosis, liver failure or hepatocellular carcinoma. The advent of new direct-acting antivirals (DAA) has revolutionized patients' chances of treatment and viral elimination. Currently, several DAA options are available on the market.Areas covered: This review focuses on the pharmacokinetics, efficacy, tolerability and safety profile of DCV-TRIO, a twice-daily fixed-dose combination of daclatasvir, asunaprevir and beclabuvir approved in Japan for the treatment of genotype 1 HCV infection.Expert opinion: The DCV-TRIO combination achieved good response rates in genotype 1 patients (SVR12 ≥ 95% in naïve subtype 1b), independently from IL28B genotype, cirrhotic status and prior interferon exposure. On the other hand, unsatisfying response rates were reported in DAA-experienced patients and the risk of RAS selection should not be underestimated. Moreover, DCV-TRIO lacks differentiation from its earlier-launched DAA rivals, presents an inconvenient twice-daily dosing schedule and is not recommended in patients with advanced liver and kidney disease. All these drawbacks considerably limit its effective commercial potential. However, it can be a therapeutic option against HCV in tailored approaches according to the needs of different markets across the world.Abbreviations AE: adverse event; ALT: alanine aminotransferase; AST: aspartate aminotransferase; ASV: asunaprevir; AUC: area under the curve; BCRP: Breast Cancer Resistance Protein; BCV: boceprevir; BID: bis in die; CI: confidence intervals; CLcr: creatinine clearance; DAA: direct acting antivirals; DCV: daclatasvir; EC50: Half maximal effective concentration; GT: genotype; HCV: Hepatitis C virus; IFN: Interferon; NHL: non-Hodgkin lymphoma; OATP: Organic anion transporting polypeptides; OR: odds ratio; P-gp: P-glycoprotein; PK: pharmacokinetics; QD: quo die; RAS: resistance-associated substitutions; SVR: sustained virological response; USD: Unites States dollar.

Pooled analysis of HCV genotype 1 resistance-associated substitutions in NS5A, NS3 and NS5B pre-and post-treatment with 12 weeks of daclatasvir, asunaprevir and beclabuvir

BACKGROUND

Daclatasvir (DCV; non-structural [NS]5A inhibitor) plus asunaprevir (ASV; NS3 inhibitor) plus beclabuvir (BCV; non-nucleoside NS5B inhibitor) is an approved regimen for hepatitis C virus (HCV) genotype (GT)-1 treatment in Japan. A comprehensive analysis of pre-treatment and treatment-emergent HCV resistance to this regimen ± ribavirin (RBV) was performed.

METHODS

Data were pooled from five Phase 2/3 studies of DCV+ASV+BCV±RBV given for 12 weeks to GT-1a- or GT-1b-infected patients. The prevalence and impact of pre-treatment resistance-associated substitutions (RAS) in NS5A, NS3, and NS5B on sustained virological response (SVR) was assessed, as were emergent RAS and their post-treatment persistence.

RESULTS

Baseline NS5A RAS (GT-1a: M28T, Q30H/L/R/S, L31M, Y93C/H; GT-1b: L31I/M, Y93C/H) were present in 5% (26/561) of GT-1a and 16% (85/537) of GT-1b sequences. SVR12 for GT-1b without RBV was 100% (82/82) with RAS and >99% (427/428) without RAS. For GT-1a, SVR12 without RAS was 97% (85/88) with RBV and 92% (410/447) without RBV; SVR12 with RAS was 100% (2/2) with RBV and 54% (13/24) without RBV. Baseline NS3 (at R155 or D168) and NS5B (at P495) RAS were rare (≤1%). Treatment-emergent NS5A RAS (mostly Q30E/H/K/R±Y93H/N) in GT-1a persisted 60 weeks post-treatment, while NS3 RAS (mostly R155K) and NS5B-P495L/S were no longer detected after 48 or 24 weeks, respectively.

CONCLUSIONS

DCV+ASV+BCV±RBV was highly efficacious in HCV GT-1 infection, including HCV GT-1b with NS5A RAS. The fitness of treatment-emergent RAS post-treatment was NS5A > NS3 > NS5B; NS3 and NS5B RAS were generally replaced by wild-type sequence within 48 weeks.

Real-world virological efficacy and safety of daclatasvir/asunaprevir/beclabuvir in patients with chronic hepatitis C virus genotype 1 infection in Japan

BACKGROUND

The virological efficacy and safety of the direct-acting antiviral (DAA) regimen consisting of daclatasvir, asunaprevir, and beclabuvir (DCV/ASV/BCV) for patients chronically infected with hepatitis C virus (HCV) genotype 1 have not been previously evaluated in Japanese real-world settings.

METHODS

In a Japanese nationwide multicenter study, the rate of sustained virologic response (SVR) and safety were analyzed in 91 patients who started the DCV/ASV/BCV regimen between November 2016 and July 2017. SVR rates were compared based on baseline patient characteristics.

RESULTS

More than 60% of patients had a history of failure to achieve SVR with interferon (IFN)-free DAA therapy. Overall, 50 of 91 patients (54.9%) achieved SVR. Multivariate analysis identified a history of failure with IFN-free DAA therapy and pretreatment HCV RNA levels as factors significantly associated with treatment failure. Whereas the SVR rate in patients without a history of IFN-free DAA therapy was 91.7% (33 of 36 patients), it was only 30.9% (17 of 55 patients) among patients with a history of IFN-free DAA therapy. The rate of discontinuation due to an adverse event was 4.4%.

CONCLUSIONS

Many patients treated with the DCV/ASV/BCV regimen have a history of a failure to achieve SVR with previous IFN-free DAA therapy. SVR rate was not as high as that in pre-approval clinical trial of this regimen in IFN-free DAA-naïve patients. In addition, most patients with a history of failure with IFN-free DAA therapy, particularly the DCV/ASV regimen, showed resistance to this regimen.

The Discovery and Early Clinical Evaluation of the HCV NS3/4A Protease Inhibitor Asunaprevir (BMS-650032)

The discovery of asunaprevir (1) began with the concept of engaging the small and well-defined S₁’ pocket of the hepatitis C virus (HCV) NS3/4A protease that was explored in the context of tripeptide carboxylic acid-based inhibitors. A cyclopropyl-acyl sulfonamide moiety was found to be the optimal element at the P₁-P₁’ interface enhancing the potency of carboxylic acid-based prototypes by 10- to >100-fold, dependent upon the specific background. Optimization for oral bioavailability identified a 1-substituted isoquinoline-based P₂* element that conferred a significant exposure advantage in rats compared to the matched 4-substituted quinoline isomer. BMS-605339 (30) was the first cyclopropyl-acyl sulfonamide derivative advanced into clinical trials that demonstrated dose-related reductions in plasma viral RNA in HCV-infected patients. However, 30 was associated with cardiac events observed in a normal healthy volunteer (NHV) and an HCV-infected patient that led to the suspension of the development program. Using a Langendorff rabbit heart model, a limited structure-cardiac liability relationship was quickly established that led to the discovery of 1. This compound, which differs from 30 only by changes in the substitution pattern of the P₂* isoquinoline heterocycle and the addition of a single chlorine atom to the molecular formula, gave a dose-dependent reduction in plasma viral RNA following oral administration to HCV-infected patients without the burden of the cardiac events that had been observed with 30. A small clinical trial of the combination of 1 with the HCV NS5A inhibitor daclatasvir (2) established for the first time that a chronic genotype 1 (GT-1) HCV infection could be cured by therapy with two direct-acting antiviral agents in the absence of exogenous immune-stimulating agents. Development of the combination of 1 and 2 was initially focused on Japan where the patient population is predominantly infected with GT-1b virus, culminating in marketing approval which was granted on July 4, 2014. In order to broaden therapy to include GT-1a infections, a fixed dose triple combination of 1, 2, and the allosteric NS5B inhibitor beclabuvir (3) was developed, approved by the Japanese health authorities for the treatment of HCV GT-1 infection on December 20, 2016 and marketed as Ximency^®.

Limitations of daclatasvir/asunaprevir plus beclabuvir treatment in cases of NS5A inhibitor treatment failure

Combined daclatasvir (DCV)/asunaprevir (ASV) plus beclabuvir (BCV) treatment shows a high virological response for genotype 1b chronic hepatitis C patients. However, its efficacy for patients for whom previous direct-acting antiviral (DAA) therapy failed is not known. We analysed the efficacy of DCV/ASV/BCV treatment for HCV-infected mice and chronic hepatitis patients. Human hepatocyte chimaeric mice were injected with serum samples obtained from either a DAA-naïve patient or a DCV/ASV treatment failure and were then treated with DCV/ASV alone or in combination with BCV for 4 weeks. DCV/ASV treatment successfully eliminated the virus in DAA-naïve-patient HCV-infected mice. DCV/ASV treatment failure HCV-infected mice developed viral breakthrough during DCV/ASV treatment, with the emergence of NS5A-L31V/Y93H HCV resistance-associated variants (RAVs) being observed by direct sequencing. DCV/ASV/BCV treatment inhibited viral breakthrough in NS5A-L31V/Y93H-mutated HCV-infected mice, but HCV relapsed with the emergence of NS5B-P495S variants after the cessation of the treatment. The efficacy of the triple therapy was also analysed in HCV-infected patients; one DAA-naïve patient and four prior DAA treatment failures were treated with 12 weeks of DCV/ASV/BCV therapy. Sustained virological response was achieved in a DAA-naïve patient and one of the DCV/ASV treatment failures through DCV/ASV/BCV therapy; however, HCV relapse occurred in the other patients with prior DCV/ASV and/or sofosbuvir/ledipasvir treatment failures. DCV/ASV/BCV therapy seems to have limited efficacy for patients with NS5A RAVs for whom prior DAA treatment has failed.

Asunaprevir: An HCV Protease Inhibitor With Preferential Liver Distribution

Asunaprevir is an inhibitor of the hepatitis C virus (HCV) NS3/4A protease, demonstrating efficacy in clinical studies in patients infected with HCV genotype 1 or 4, with either peginterferon/ribavirin or combinations of direct-acting antivirals. Because of preferential distribution of asunaprevir to the liver via organic anion-transporting polypeptide (OATP)-mediated transport, asunaprevir demonstrates high apparent oral clearance and very low plasma concentrations. Asunaprevir plasma concentrations are markedly increased by single-dose rifampin (an OATP inhibitor) and in subjects with moderate to severe hepatic impairment. In addition, modestly higher plasma concentrations of asunaprevir have been noted in subjects infected with HCV relative to healthy subjects and in Asian subjects relative to whites. At the marketed dose, infrequent hepatic transaminase abnormalities were poorly predicted by plasma concentrations. For a compound with these characteristics, hepatic concentrations may have provided an improved understanding of the in vivo pharmacokinetic and pharmacodynamic data to support decision making during development.

Discovery of Beclabuvir: A Potent Allosteric Inhibitor of the Hepatitis C Virus Polymerase

The discovery of beclabuvir occurred through an iterative series of structure-activity relationship studies directed at the optimization of a novel class of indolobenzazepines. Within this research, a strategic decision to abandon a highly potent but physiochemically problematic series in favor of one of lower molecular weight and potency was key in the realization of the program’s objectives. Subsequent cycles of analog design incorporating progressive conformational constraints successfully addressed off-target liabilities and identified compounds with improved physiochemical profiles. Ultimately, a class of alkyl-bridged piperazine carboxamides was found to be of particular interest, and from this series, beclabuvir was identified as having superior antiviral, safety, and pharmacokinetic properties. The clinical evaluation of beclabuvir in combination with both the NS5A replication complex inhibitor daclatasvir and the NS3 protease inhibitor asunaprevir in a single, fixed-dose formulation (Ximency) resulted in the approval by the Japanese Pharmaceutical and Food Safety Bureau for its use in the treatment of patients infected with genotype 1 HCV.

Direct-Acting Antivirals in Chronic Hepatitis C Genotype 4 Infection in Community Care Setting

Background

Limited data exists comparing the safety, tolerability, and efficacy of direct-acting antivirals (DAAs) in patients with chronic hepatitis C genotype 4 (HCV GT-4) in the community practice setting. We aim to evaluate the treatment response of DAAs in these patients.

Methods

All the HCV GT-4 patients treated with DAAs between January 2014 and October 2017 in a community clinic setting were retrospectively analyzed. Pretreatment baseline patient characteristics, treatment efficacy with sustained virologic response (SVR) at 12 weeks post treatment (SVR12), and adverse reactions were assessed.

Results

Fifty-two patients of Middle Eastern (primarily Egyptian) descent were included in the study. Thirty-two patients were treated with ledipasvir/sofosbuvir (Harvoni^®) ± ribavirin, 12 patients were treated with ombitasvir/paritaprevir/ritonavir/dasabuvir (ViekiraPak^®) ± ribavirin, and eight patients were treated with sofosbuvir/Velpatasvir (Epclusa^®). Ten patients (19.2%) had compensated cirrhosis. Overall, SVR at 12 weeks was achieved in 94% in patients who received one of the three DAA regimens (93.8% in Harvoni^® group, 91.7 % in ViekiraPak^® group and 100% in Epclusa^® group). Prior treatment status and type of regimen used in the presence of compensated cirrhosis had no statistical significance on overall SVR achievement (P value = 0.442 and P value = 0.091, respectively). The most common adverse effect was fatigue (27%).

Conclusions

In the real-world setting, DAAs are effective and well tolerated in patients with chronic HCV GT-4 infection with a high overall SVR rate of 94%. Large-scale studies are needed to further assess this SVR in these groups.

Sofosbuvir plus daclatasvir with or without ribavirin in 551 patients with hepatitis C-related cirrhosis, genotype 4

BACKGROUND

The Daclatasvir and Sofosbuvir combination therapy (SOF/DCV) has shown efficacy in patients with chronic hepatitis C in clinical trials.

AIM

To investigate the efficacy and safety of SOF/DCV for treatment of patients with hepatitis C-related liver cirrhosis genotype 4.

METHODS

Multicentre study involving 551 patients with liver cirrhosis genotype 4; 432 naïve patients and 119 treatment-experienced patients. All patients received SOF (400 mg) and DCV (60 mg) daily in addition to weight-based ribavirin (RBV) for 12 weeks and when RBV is contraindicated the treatment duration was extended to 24 weeks.

RESULTS

Sustained virological response at 12 weeks after end of treatment (SVR12) rate was 92% in naïve cirrhotic patients and 87% in previous treated patients (by ITT analysis). Virological failure was infrequent, occurring in 42 patients (8%) overall. Thirty-two (6%) were non responders; and 10 (2%) cases were relapsers, 31 patients (7%) were CTP-A and 11 (13.3%) patients were CTP-B (by ITT analysis). The most common adverse events were anaemia, fatigue, headache, pruritus. Serious side effects were recorded mainly in CTP-B cirrhotic patients including HCC and hepatic encephalopathy.

CONCLUSIONS

The SOF/DCV combination therapy has proven efficacy and safety in treating patients with hepatitis C-related liver cirrhosis genotype 4 in a large cohort of patients in the real world.

Efficacy of daclatasvir-based quadruple therapy in nonresponder patients infected by hepatitis C virus genotype 4: the ANRS HC32 QUATTRO study

BACKGROUND

A few direct antiviral agents have been studied in difficult-to-treat patients infected by hepatitis C virus (HCV) genotype 4 (GT4). The efficacy of daclatasvir (DCV), asunaprevir (ASV), pegylated interferon and ribavirin (Peg-IFN/RBV) association was investigated in these patients.

PATIENTS AND METHODS

This open-label, single-arm, phase 2 study was conducted in HCV GT4 patients who were null or partial responders to Peg-IFN/RBV. Patients received 24 weeks of DCV (60 mg, once daily), ASV (100 mg, twice daily) and Peg-IFN/RBV. The primary endpoint was sustained virologic response at post-treatment week 12 [sustained virologic response (SVR)12].

RESULTS

Sixty patients were included; 45 (75%) were previous null responders and 27 (45%) had cirrhosis. The most frequent subtypes were GT4a (48%) and GT4d (27%) with 25% of the patients being infected with other subtypes such as 4c, 4r, 4f, 4k, 4j and 4q. The global SVR12 was 95% (90% confidence interval: 90.4-99.6) and 96.3% (90% confidence interval: 87.5-99.5) in cirrhotic patients. All patients achieving SVR12 also achieved SVR24. Previous Peg-IFN/RBV response, IL28b genotype, cirrhosis status or GT4 subtypes did not influence SVR12 rates. Serious adverse events occurred in 13% of the patients, four being cirrhotic and four noncirrhotic. Three (5%) patients stopped HCV therapy prematurely: one because of virologic breakthrough and two because of serious adverse events. Grade 3/4 laboratory abnormalities included leukopenia (33%), neutropenia (27%), thrombocytopenia (4%) and transaminases increase (2%).

CONCLUSION

Association of DCV plus ASV and peg-IFN/RBV for 24 weeks demonstrated a high rate of SVR12 in HCV GT4-infected prior nonresponders, independently of the cirrhotic status or the GT4 subtype. The safety profile was acceptable, even in cirrhotic patients.

Efficacy of Interferon-Free Therapies for Chronic Hepatitis C: A Systematic Review of All Randomized Clinical Trials

BACKGROUND AND OBJECTIVES

Second-generation direct-acting antivirals (DAAs) have recently arisen as more effective and safer treatments for chronic hepatitis C. These drugs can be combined into treatments without interferon (IFN), and are therefore called IFN-free therapies.

OBJECTIVE

The objective of this study systematic review was to evaluate the efficacy of IFN-free therapies for the treatment of chronic hepatitis C, and thus increase the clinical evidence for these therapies.

METHODS

A systematic review was conducted in accordance with Cochrane Collaboration recommendations. A search was performed in six different electronic databases using 'clinical trials', 'hepatitis C' and 'interferon-free' as the main descriptors, and studies that conformed to the inclusion criteria had their data extracted, including study information, baseline characteristics, and efficacy outcomes (sustained virologic response, rapid virologic response, and virologic failure).

RESULTS

Sixty-four randomized clinical trials including 15 different therapies were included in a total of 15,731 patients infected with the hepatitis C virus, mostly with genotype 1, and mainly treated for 12 or 24 weeks. The sustained virologic response rate after 12 weeks of treatment was approximately 89%, while the virologic failure rate was below 5%.

CONCLUSIONS

Second-generation DAAs presented several advantages: virologic response values higher than the average achieved by previous IFN-based therapies, reduced treatment duration, and the possibility of different combinations of therapies to meet patient needs. Thus, IFN-free therapies appear to be valuable alternatives for the treatment of chronic hepatitis C.

Discovery of BMS-961955, an allosteric inhibitor of the hepatitis C virus NS5B polymerase

The synthesis, structure-activity relationship (SAR) data, and further optimization of the metabolic stability and pharmacokinetic (PK) properties for a previously disclosed class of cyclopropyl-fused indolobenzazepine HCV NS5B polymerase inhibitors are described. These efforts led to the discovery of BMS-961955 as a viable contingency backup to beclabuvir which was recently approved in Japan for the treatment of HCV as part of a three drug, single pill combination marketed as Ximency^TM.

Real life Egyptian experience of efficacy and safety of Simeprevir/Sofosbuvir therapy in 6211 chronic HCV genotype IV infected patients

BACKGROUND & AIMS

Major changes have emerged during the last few years in the therapy of chronic HCV. Several direct acting antiviral agents have been developed showing potent activity with higher rates of sustained virological response, even in difficult-to-treat patients. This study explores real life experience concerning efficacy, safety and possible predictors of response for the first cohort of Egyptian patients with chronic HCV genotype IV treated with Sofosbuvir/Simprevir combination therapy.

METHODS

This real life study recruited the first (6211) chronic HCV genotype IV Egyptian patients, who received antiviral therapy in viral hepatitis specialized treatment centres affiliated to the National committee for control of viral hepatitis. All enrolled patients received 12 weeks course of daily combination of sofosbuvir (400 mg) and simeprevir (150 mg). Patients were closely monitored for treatment safety and efficacy.

RESULTS

Overall sustained virological response 12 rate was 94.0% while the end of treatment response rate was 97.6%. sustained virological response 12 rates in easy and difficult-to-treat groups were 96% and 93% respectively. Univariate and multivariate logistic regression analysis revealed significant association of low albumin (<3.5), cirrhosis and Fib-4 score (>3.25) with treatment failure. Fatal adverse events occurred in 23/6211 cases (0.37%) due to liver cell failure adverse events or SAEs leading to treatment discontinuation occurred in 97 patients (1.6%).

CONCLUSION

Sofosbuvir/Simeprevir combination is an effective and well tolerated regimen for patients with chronic HCV genotype IV.

NS5A inhibitors for the treatment of hepatitis C infection

Today, we are witnessing a new era for the treatment of hepatitis C with excellent rates of virologic response and very good safety profiles. Among the many classes of direct-acting antivirals, the inhibitors of nonstructural protein 5A are particularly interesting. NS5A is a phosphorylated protein with a relevant role in viral replication. HCV-NS5A inhibitors show high potency, very good safety profile and high barrier to resistance. The amazing in vitro effectiveness of this class is associated with great efficacy in clinical trials in combination protocols with antivirals of other classes, with sustained virological response (SVR) obtained in more than 90% of patients. Herein, we sought to review the current knowledge regarding the NS5A protease complex inhibitors with special emphasis on clinical efficacy and development of viral resistance.

Current therapy for chronic hepatitis C: The role of direct-acting antivirals

One of the most exciting developments in antiviral research has been the discovery of the direct-acting antivirals (DAAs) that effectively cure chronic hepatitis C virus (HCV) infections. Based on more than 100 clinical trials and real-world studies, we provide a comprehensive overview of FDA-approved therapies and newly discovered anti-HCV agents with a special focus on drug efficacy, mechanisms of action, and safety. We show that HCV drug development has advanced in multiple aspects: (i) interferon-based regimens were replaced by interferon-free regimens; (ii) genotype-specific drugs evolved to drugs for all HCV genotypes; (iii) therapies based upon multiple pills per day were simplified to a single pill per day; (iv) drug potency increased from moderate (∼60%) to high (>90%) levels of sustained virologic responses; (v) treatment durations were shortened from 48 to 12 or 8 weeks; and (vi) therapies could be administered orally regardless of prior treatment history and cirrhotic status. However, despite these remarkable achievements made in HCV drug discovery, challenges remain in the management of difficult-to-treat patients.

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HCV genotype-specific drugs evolve to pan-genotypic drugs.

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Drug potency increases from moderate (∼60%) to high (>90%) levels of sustained virologic response.

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Treatment durations are shortened from a 48-week to 12-week or 8-week period.

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HCV therapies based upon multiple pills per day are simplified to a single pill per day.

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HCV therapies are administered orally regardless of prior treatment history and cirrhotic status.

Functionalized triazines as potent HCV entry inhibitors

A series of potent and novel acylsulfonamide-bearing triazines were synthesized and the structure-activity relationships (SARs) as HCV entry inhibitors were evaluated. This acylsulfonamide series was derived from an early lead, 4-(4-(1-(4-chlorophenyl)cyclopropylamino)-6-(2,2,2-trifluoroethoxy)-1,3,5-triazin-2-ylamino)benzoic acid wherein the carboxylic acid was replaced with an acylsulfonamide moiety. This structural modification provided a class of compounds which projected an additional vector off the terminus of the acylsulfonamide functionality as a means to drive activity. This effort led to the discovery of potent analogues within this series that demonstrated sub-nanomolar EC₅₀ values in the HCV pseudotype particle (HCVpp) assay.

The practical management of chronic hepatitis C infection in Japan - dual therapy of daclatasvir + asunaprevir

Without treatment, many of the 200 million people worldwide with chronic hepatitis C virus (HCV) infection will develop cirrhosis or liver cancer. Japan was the first nation to approve an interferon-free therapy for HCV, and sustained viral response (SVR) rates >90% have been achieved with asunaprevir, a protease inhibitor, plus daclatasvir, an inhibitor of the non-structural 5A (NS5A) protein. Areas covered: This review provides an overview of the results from both clinical trials and real world experience with asunaprevir and daclatasvir therapy focused primarily on Japan. A literature search using the keywords 'asunaprevir,' 'daclatasvir,' 'interferon-free therapy,' and 'direct-acting antiviral drugs' was initially used to select relevant literature for inclusion in the review. Expert commentary: While not approved in the United States, dual therapy with asunaprevir plus daclatasvir has already been successfully used in Japan and throughout East Asia to treat many thousands of patients. Pre-existing or treatment-emergent NS5A-Y93 or -L31 resistance-associated variants (RAVs) may lead to viral breakthrough, and alternative therapies should be considered for these patients, but patients who harbor NS5A RAVs only at low frequency are likely to achieve SVR. The therapy has also been shown to be safe and effective with renal dysfunction or liver cirrhosis.

Efficacy and Safety of Daclatasvir in Hepatitis C: An Overview

Hepatitis C virus (HCV) infection is a growing public health concern, with 184 million people infected worldwide. During the past decade, interferon has been the backbone of HCV treatment, even though it remains far from ideal. The latest development of the new direct antivirals has drastically changed the treatment approach for chronic hepatitis C (CHC). Inhibitors of the HCV NS5A region have garnered remarkable interest among treating physicians, due to their high potency and favourable safety profile. In particular, treatment with daclatasvir (DCV) has yielded high rates of vriologic response in patients infected with genotype (Gt) 1 and Gt 3, when used in combination with other antivirals of a different class, such as sofosbuvir. Although few data are available for DCV treatment of the other Gts, the results in patients with Gt 2 and Gt 4 infection appear promising, as do those for unique patient populations. NS5A-resistant viral variants can pre-exist or emerge after treatment failure for the HCV NS5A inhibitors. Nonetheless, DCV-resistant viral variants continue to be sensitive to interferon and other classes of antivirals such as NS3/4A and NS5B inhibitors. Herein, we aimed to provide an overview of the current knowledge about DCV in the treatment of CHC.

Ledipasvir plus sofosbuvir for 12 weeks in patients with hepatitis C genotype 4 infection

Genotype 4 hepatitis C virus (HCV) was considered difficult to treat in the era of pegylated interferon-alpha (Peg-IFN-α) and ribavirin regimens. We evaluated the efficacy and safety of therapy with the nonstructural (NS) 5A inhibitor, ledipasvir, combined with the NS5B polymerase inhibitor, sofosbuvir, in patients with HCV genotype 4. In this phase 2, open-label study, 44 patients (22 treatment naïve and 22 treatment experienced) received a fixed-dose combination tablet of 90 mg of ledipasvir and 400 mg of sofosbuvir orally once-daily for 12 weeks. The primary endpoint was the percentage of patients with HCV RNA <15 IU/mL 12 weeks after stopping therapy (SVR12). Among study participants, HCV genotype 4 subtypes were well represented (4a, n = 25; 4d, n = 10; other subtypes, n = 9). Ten patients (23%) had compensated cirrhosis. Of the 22 treatment-experienced patients, 21 (95%) had a non-CC IL-28B genotype. All 44 patients completed the full 12 weeks of dosing. The SVR12 rate was 93% (41 of 44; 95% confidence interval, 81-99). SVR12 rates were similar between treatment-naïve (95%; 21 of 22) and treatment-experienced (91%; 20 of 22) patients. All 3 patients who did not achieve SVR12 had virological relapse within 4 weeks of the end of treatment; all 3 had baseline HCV RNA ≥800,000 IU/mL, a non-CC IL-28B genotype, and pretreatment NS5A resistance-associated variants. None of the patients who relapsed had cirrhosis. The most common adverse events were asthenia, headache, and fatigue. No patients experienced a serious adverse event.

CONCLUSION

The all-oral regimen of ledipasvir and sofosbuvir is an effective and safe treatment for a wide range of HCV 4 subtypes in both treatment-naïve and -experienced patients, including those with compensated cirrhosis. (EudraCT number: 2013-003978-27; Clinicaltrials.gov NCT02081079) (Hepatology 2016;64:1049-1056).

Management of hepatitis C genotype 4 in the directly acting antivirals era

Genotype 4 chronic hepatitis C (G4 HCV) accounts for 13% of worldwide HCV infections; with 10 million people infected with the virus across the world. Up to the end of 2013, the only treatment option for G4 HCV was treatment with pegylated interferon and ribavirin for 24-48 weeks. Since late 2013, treatment of G4 HCV has been transformed by the licensing of many directly acting antiviral agents (DAA). It is an exciting time to be involved in the management of HCV generally and G4 particularly. Interferon-free DAA regimens are now a reality for G4 HCV. This review will highlight these developments and discuss the data behind the use of these drugs. It will also highlight future regimens that are likely to be available over the coming years.

Daclatasvir-based Treatment Regimens for Hepatitis C Virus Infection: A Systematic Review and Meta-Analysis

CONTEXT

Direct acting antivirals (DAAs) have recently emerged as a promising therapeutic regimen for the treatment of hepatitis C virus (HCV) infection, which is a major public health problem. Among the known DAAs, daclatasvir (DCV), an inhibitor of the non-structural 5A protein, has been used in combination with several drugs for treatment of infection with HCV of different genotypes under different conditions. We conducted a systematic review and meta-analysis of combination therapy with DCV.

EVIDENCE ACQUISITION

We performed a systematic search in PubMed, Scopus, Science Direct and Web of Science with appropriate keywords for DCV. Studies that evaluated any regimen containing DCV and reported the sustained virological response (SVR) 12 weeks after therapy based on the HCV genotype, treatment duration and use of ribavirin (RBV) were included. The selected studies were considered for meta-analysis using STATA 11.0.

RESULTS

We found six different regimens containing DCV: DCV/asunaprevir (ASV), DCV/ASV/beclubavir, DCV/pegylated interferon lambda or alpha/RBV with or without ASV, DCV/simeprevir, DCV/VX-135 and DCV/sofosbuvir (SOF). Most of these regimens were used for the treatment of HCV genotype 1 infections, and in most cases, treatment failure was noted in subtype 1a infections. Among all these regimens, DCV/SOF with or without RBV for 12 or 24 weeks was found to be an efficacious approach for treatment of different types of patients with infections with different HCV genotypes.

CONCLUSIONS

Among the treatment regimens containing DCV, DCV/SOF has the highest SVR rate for the treatment of infection with different HCV genotypes in different patient contexts; thus, this regimen shows promise for the treatment of HCV infections.

Discovery of a Potent Acyclic, Tripeptidic, Acyl Sulfonamide Inhibitor of Hepatitis C Virus NS3 Protease as a Back-up to Asunaprevir with the Potential for Once-Daily Dosing

The discovery of a back-up to the hepatitis C virus NS3 protease inhibitor asunaprevir (2) is described. The objective of this work was the identification of a drug with antiviral properties and toxicology parameters similar to 2, but with a preclinical pharmacokinetic (PK) profile that was predictive of once-daily dosing. Critical to this discovery process was the employment of an ex vivo cardiovascular (CV) model which served to identify compounds that, like 2, were free of the CV liabilities that resulted in the discontinuation of BMS-605339 (1) from clinical trials. Structure-activity relationships (SARs) at each of the structural subsites in 2 were explored with substantial improvement in PK through modifications at the P1 site, while potency gains were found with small, but rationally designed structural changes to P4. Additional modifications at P3 were required to optimize the CV profile, and these combined SARs led to the discovery of BMS-890068 (29).

Safety of interferon-free therapies for chronic hepatitis C: a network meta-analysis

WHAT IS KNOWN AND OBJECTIVE

Interferon-free (IFN-free) therapies for hepatitis C virus (HCV) have been developed to provide more effective, tolerable and safer therapeutic strategies. To date, no network meta-analysis (NMA) evaluating the safety profile of these regimens has been performed. This systematic review and NMA aimed to evaluate safety outcomes of IFN-free treatment options for chronic hepatitis C.

METHODS

A systematic review was performed according to PRISMA and Cochrane recommendations. A literature search was conducted in PubMed/Medline, Scopus, Cochrane Library, International Pharmaceutical Abstracts and Web of Science electronic databases and included only randomized clinical trials that provided safety outcomes of interest of evaluated second-generation direct-acting antivirals: incidence of any adverse events (AEs) and serious AE. NMA allowed estimating probability for the relative safety of the interventions. A consistency model was used to draw conclusions about relative safety of treatments, presented as odds ratio (OR) and corresponding 95% credible interval (CrI).

RESULTS

Fifty-one clinical trials were included (13 089 participants). Most participants had hepatitis C genotype 1 virus (76%) and were treated for 12 weeks. Two NMAs were built to investigate the incidence of AEs and serious AEs, comparing 13 and 10 IFN-free treatment options, respectively. For the outcome incidence of AEs, few significant differences were observed, which were explained by the presence of RBV. Elbasvir with grazoprevir and placebo were both safer than ombitasvir in combination with paritaprevir, ritonavir, daclatasvir plus RBV [ORs with 95% Crl of 4·09 (1·17-14·09) and 2·40 (1·19-4·77), respectively] and sofosbuvir with RBV [ORs with 95% Crl of 0·22 (0·07-0·72) and 2·69 (1·53-4·80), respectively]. Furthermore, elbasvir with grazoprevir was safer than sofosbuvir used with velpatasvir and RBV [OR 0·19 (95% CrI 0·03-0·98)]; ombitasvir in combination with paritaprevir, ritonavir, daclatasvir was safer than the same therapy but combined with RBV [OR 2·14 (95% CrI 1·09-4·44)]; and sofosbuvir used with velpatasvir was safer than sofosbuvir with RBV [OR 2·07 (95% CrI 1·13-3·79)]. Elbasvir with grazoprevir (50%) followed by placebo (28%) had the highest probabilities of less AEs. No significant differences were observed for serious AE outcomes.

WHAT IS NEW AND CONCLUSION

This meta-analysis included a large number of therapies. Small differences were observed in any AEs, but not in serious AEs.

Hepatitis C Virus: Current and Evolving Treatments for Genotype 4

Hepatitis C virus (HCV) is a major cause of chronic liver disease, with more than 170 million infected individuals worldwide. Genotype 4 is the most frequent cause of chronic hepatitis C in the Middle East and sub-Saharan Africa. It has recently spread to southern Europe. The introduction of all-oral, interferon-free regimens that combine direct-acting antivirals (DAAs) has significantly advanced HCV treatment. High efficacy rates, short treatment duration, and favorable adverse event profiles have been demonstrated with multiple regimens, both with and without ribavirin. This review discusses management of patients with HCV genotype 4 chronic hepatitis, in the era of DAAs.

New hepatitis C therapies for special patient populations

INTRODUCTION

Chronic hepatitis C virus (HCV) infection has become a curable disease. More than 90% sustained virologic response rates have been obtained with 8-24 weeks of treatment with distinct combinations of direct-acting antivirals (DAA) in most registration trials. However, outcomes in real-world patients tend to be lower and treatment of special patient populations is often challenging.

AREAS COVERED

We address the treatment of chronic hepatitis C with DAA in major special patient populations, such as HIV-positive persons, transplant recipients, patients with advanced cirrhosis, renal insufficiency, hepatitis B or D coinfection, injection drug users (IDUs) and prior DAA failures.

EXPERT OPINION

Drug interactions between DAA and medications given to persons with HIV infection or transplant recipients can result in treatment failure and adverse events. Severe organ dysfunction as in kidney insufficiency or decompensated cirrhosis may lead to DAA overexposure and toxicities. Dysfunctional social circumstances and behavior are associated to poor drug adherence and increased risk for HCV re-infection in active IDUs. Finally, DAA response might be impaired by viral interference in patients with hepatitis B or D coinfection or drug resistance in HCV either at baseline or after prior DAA failures.

Daclatasvir-containing all-oral regimens for the treatment of hepatitis C virus infection

The treatment of chronic hepatitis C is revolutionizing rapidly. The aim of this study is to review the efficacy and safety of daclatasvir (DCV)-containing all-oral regimens in clinical studies for chronic hepatitis C treatment. Using PubMed and search terms of 'DCV,' 'hepatitis C virus (HCV) treatment,' and 'HCV NS5A inhibitors,' literature on the clinical development of DCV, as well as abstracts presented at the April 2015 annual meeting of the European Association for the Study of the Liver (EASL) and November 2014 annual meeting of the American Association for the Study of Liver Diseases were reviewed. The final search was undertaken on 14 July 2015. With its potent antiviral activity to all HCV genotypes (GT) demonstrated in preclinical, phases 1-3 studies, DCV has been acting as a very competent team player in clinical trials of all-oral regimens. It is generally safe and well tolerated with a low genetic barrier to resistance and low potential for drug-drug interaction. Administered with a non-structural protein 3 (NS3) protease inhibitor (asunaprevir, ASV) with or without a non-nucleoside NS5B polymerase inhibitor (beclabuvir, BCV), or a nucleotide NS5B polymerase inhibitor (sofosbuvir, SOF), DCV is able to achieve greater than a 90-% HCV eradication rate in both treatment-naïve and treatment-experienced patients with GT 1. A triple combination regimen with DCV/ASV/BCV results in 100% sustained virologic response (SVR) rates in HCV GT 4 treatment-naïve subjects. DCV/SOF combination also had demonstrated up to 90-% SVR rates in GT 3-infected non-cirrhotic patients. The efficacy and safety of DCV-containing all-oral regimens highlight a new era of interferon-free therapy for chronic hepatitis C.

Interferon-free combination therapies for the treatment of hepatitis C: current insights

The hepatitis C virus (HCV) treatment landscape has rapidly changed over the past 5 years. The development of direct-acting antiviral (DAA) agents that specifically target various steps in the HCV lifecycle has revolutionized therapeutic options for patients with HCV, with the development of highly effective and well-tolerated oral interferon-free regimens. There are many DAAs that are currently in development or have recently been approved, which target different nonstructural HCV proteins and host targets that are essential for HCV replication. This review will focus on the different classes of DAAs and the various combinations that are in advanced development for the treatment of chronic HCV infection and will focus on the different regimens in specific patient populations.

The new era of hepatitis C virus therapy

The hepatitis C virus (HCV) has a significant medical and economic impact on societies around the world, and it has been estimated that 130-180 million people are infected with HCV. Therapies for HCV are currently undergoing a revolution. In recent years, several new treatments have been approved by the United States Food and Drug Administration, and many other treatments are in phase II or III clinical trials, including direct antiviral agents (DAAs). Due to recent major advances in the field of HCV therapy, a summary of findings on new HCV therapies are provided in this review article, including reports on new DAAs.

Daclatasvir: A NS5A Replication Complex Inhibitor for Hepatitis C Infection

OBJECTIVES

To review the pharmacology, efficacy, and safety of daclatasvir in the treatment of patients with chronic hepatitis C virus (HCV) infection.

DATA SOURCES

A literature search through EMBASE and PubMed was conducted (January 1966 to August 2015) using the terms BMS-790052, daclatasvir, and hepatitis C. References from retrieved articles were reviewed for any additional material. Additionally, the new drug application and prescribing information were retrieved.

STUDY SELECTION/DATA EXTRACTION

The literature search was limited to human studies published in English. Phase 1, 2, and 3 studies describing the pharmacology, pharmacokinetics, efficacy, and safety of daclatasvir for HCV were identified.

DATA SYNTHESIS

Daclatasvir, a nonstructural 5A protein inhibitor, combined with sofosbuvir, is indicated for adult patients with chronic HCV genotype 3 regardless of treatment or cirrhosis status. The phase III ALLY-3 trial (n = 152) demonstrated that daclatasvir taken once daily with sofosbuvir for 12 weeks was effective at achieving sustained virological response (SVR) rates in treatment-naïve (97%) and treatment-experienced (94%) patients without cirrhosis. Patients with cirrhosis had significantly lower SVR rates (58 and 69%, respectively). The most common adverse drug events associated with daclatasvir and sofosbuvir in ALLY-3 were headache (20%), fatigue (19%), and nausea (12%).

CONCLUSIONS

Daclatasvir, when combined with sofosbuvir, is an effective agent to treat HCV genotype 3, with SVR rates above 90% for patients without cirrhosis who are treatment naïve or experienced. SVR rates for treatment-naïve or -experienced patients with cirrhosis are not as robust (58%-69%).

Sofosbuvir plus ribavirin for treating Egyptian patients with hepatitis C genotype 4

BACKGROUND & AIMS

Egypt has the highest prevalence of chronic hepatitis C virus (HCV) infection in the world, and more than 90% of patients are infected with genotype 4 virus. We evaluated the efficacy and safety of the HCV polymerase inhibitor sofosbuvir in combination with ribavirin in HCV genotype 4 patients in Egypt.

METHODS

Treatment-naïve or treatment-experienced patients with genotype 4 HCV infection (n=103) were randomly assigned to receive either 12 or 24 weeks of sofosbuvir 400 mg and ribavirin 1000-1200 mg daily. Randomization was stratified by prior treatment experience and by presence or absence of cirrhosis. The primary endpoint was the percentage of patients with HCV RNA <25 IU/ml 12 weeks after therapy (SVR12).

RESULTS

Among all patients, 52% had received prior HCV treatment and 17% had cirrhosis at baseline. SVR12 rates were 90% (46/51) with 24 weeks and 77% (40/52) with 12 weeks of sofosbuvir and ribavirin therapy. Patients with cirrhosis at baseline had lower rates of SVR12 (63% 12 weeks, 78% 24 weeks) than those without cirrhosis (80% 12 weeks, 93% 24 weeks). The most common adverse events were fatigue, headache, insomnia, and anemia. Two patients experienced serious adverse events (cerebral ischemia, dyspnea). No adverse events resulted in treatment discontinuation.

CONCLUSION

Sofosbuvir plus ribavirin for 12 or 24 weeks is effective in treating both treatment-naïve and treatment-experienced Egyptian patients with genotype 4 HCV.

Efficacy and safety of sofosbuvir-based triple therapy in hepatitis C genotype 4 infection

BACKGROUND

There are only limited data on sofosbuvir-based treatment regimens in hepatitis C virus (HCV) genotype 4-infected patients.

AIMS

To evaluate safety and efficacy of sofosbuvir-based triple-therapy in HCV genotype 4 infection.

METHODS

All HCV genotype 4-infected patients who started sofosbuvir-based triple-therapy at our two centres between January and June 2014 were prospectively included (N=24) and compared to genotype 4 patients treated with peginterferon/ribavirin between January 2001 and December 2012 (N=63).

RESULTS

The demographics in the sofosbuvir group and the controls were comparable (males 87.5% and 82.5%; mean age 46.7±9.0 years and 42.0±9.8 years, respectively). Sustained virological response was achieved in 83.3% in the sofosbuvir group and in 47.6% of controls (P=0.003). Fatigue (P=0.007), flu-like (P=0.015), gastrointestinal (P<0.001), dermatologic (P<0.001) and psychiatric symptoms (P=0.022) were more common in the control group.

CONCLUSIONS

In our real-life cohort, sofosbuvir-based triple therapy confirmed its high efficacy and safety for chronic genotype 4 hepatitis C.

Interferon-free therapy for hepatitis C: The hurdles amid a golden era

The long awaited all-oral therapy for hepatitis C virus infection has officially been inaugurated by the registration of the hepatitis C nucleotide inhibitor sofosbuvir in a combination regimen with ribavirin. More recently, the oral array to treat hepatitis C has been enriched by the arrival of the NS5A inhibitors ledipasvir (also in a single formulation with sofosbuvir, Harvoni(®)) and daclatasvir; the protease inhibitor simeprevir, and the Viekirax(®)+Exviera™ regimen based on the ritonavir boosted protease inhibitor paritaprevir; the NS5A inhibitor ombitasvir, and the non-nucleoside inhibitor dasabuvir. Owing to the budget-breaking price of the newer oral medicines, the Italian National Health System elected to restrict reimbursement of oral anti-hepatitis C therapy to patients with advanced liver disease or transplanted organs, and those who are interferon unable, only. While this therapeutic strategy harmonizes with principles of distributive justice, at the same time it fuelled the argument of its doubtful cost-effectiveness, owing to the National Health System's reimbursement of the sole sofosbuvir+ribavirin regimen, which has suboptimal efficacy against the prevalent hepatitis C virus genotype 1b. As a consequence, we are left with a number of uncertainties regarding the optimal treatment modality for certain subgroups of hepatitis C patients, and the clinical benefits provided by hepatitis C virus clearance in patients with advanced liver disease.

Randomized controlled trial of the NS5A inhibitor daclatasvir plus pegylated interferon and ribavirin for HCV genotype-4 (COMMAND-4)

BACKGROUND

Treatment options for HCV genotype-4 (GT4) are limited. This Phase III study (COMMAND-4; AI444-042) evaluated the efficacy and safety of daclatasvir (DCV), a pan-genotypic HCV NS5A inhibitor, with pegylated interferon-α2a/ribavirin (PEG-IFN/RBV) in treatment-naive patients with HCV GT4 infection.

METHODS

Patients were randomly assigned (2:1; blinded) to treatment with DCV 60 mg (n=82) or placebo (n=42) once daily plus PEG-IFN 180 µg weekly and RBV 1,000-1,200 mg/day (weight-based) twice daily. DCV-treated patients with undetectable HCV RNA at weeks 4 and 12 (eRVR) received 24 weeks of DCV plus PEG-IFN/RBV; those without eRVR received an additional 24 weeks of PEG-IFN/RBV. All placebo-treated patients received 48 weeks of PEG-IFN/RBV. The primary end point was sustained virological response (SVR) at post-treatment week 12 (SVR12).

RESULTS

Patients were 75% IL28B non-CC and 11% had cirrhosis. SVR rates (HCV RNA < lower limit of quantitation [LLOQ]) at post-treatment week 12 or later (imputed to include patients missing SVR12 assessments but had SVR after post-treatment week 12) were 82% (67/82) with DCV plus PEG-IFN/RBV versus 43% (18/42) with PEG-IFN/RBV (P<0.0001). In DCV recipients, SVR12 rates were comparable across subgroups. The safety and tolerability profile of DCV plus PEG-IFN/RBV was comparable to that of PEG-IFN/RBV. Discontinuations due to adverse events occurred in 4.9% of patients receiving DCV plus PEG-IFN/RBV and 7.1% of patients receiving PEG-IFN/RBV.

CONCLUSIONS

In treatment-naive patients with HCV GT4 infection, DCV plus PEG-IFN/RBV achieved higher SVR12 rates than PEG-IFN/RBV alone. These data support DCV-based regimens for treatment of HCV GT4 infection, including all-oral combinations with other direct-acting antivirals (AI444-042; ClinicalTrials.gov NCT01448044).

Hepatitis C virus genotype 4 resistance and subtype demographic characterization of patients treated with ombitasvir plus paritaprevir/ritonavir

Hepatitis C virus (HCV) genotype 4 (GT4) is genetically diverse, with 17 confirmed subtypes, and comprises approximately 13% of infections worldwide. In this study, we identified GT4 subtypes by phylogenetic analysis, assessed differences in patient demographics across GT4 subtypes, examined baseline sequence variability among subtypes and the potential impact on treatment outcome, and analyzed the development of viral resistance in patients who received a regimen of ombitasvir (nonstructural protein 5A [NS5A] inhibitor) plus ritonavir-boosted paritaprevir (NS3/4A inhibitor) with or without ribavirin (RBV) for the treatment of HCV GT4 infection. Phylogenetic analysis of HCV NS3/4A, NS5A, and NS5B nucleotide sequences identified 7 subtypes (4a, 4b, 4c, 4d, 4f, 4g/4k, and 4o) among 132 patient samples. Subtype prevalence varied by country, and the distributions of patient birth cohort and race were significantly different across GT4 subtypes 4a, 4d, and non-4a/4d. Baseline amino acid variability was detected in NS5A across GT4 subtypes but had no impact on treatment outcome. Three patients experienced virologic failure and were infected with subtype 4d, and the predominant resistance-associated variants at the time of failure were D168V in NS3 and L28V in NS5A. Overall, high response rates were observed among patients infected with 7 HCV GT4 subtypes, with no impact of baseline variants on treatment outcome. GT4 subtype distribution in this study differed based on patient demographics and geography.

What does the pharmacological future of treating chronic hepatitis C look like?

Development of direct acting antivirals has revolutionized the standard of care for the treatment of hepatitis C virus. New interferon-free regimens provide sustained virologic response rates of >90% in many genotype 1 patients with only 12 weeks of oral therapy. This review will provide a brief overview of current standards of care with a summary of the evidence supporting the recommended combinations of direct acting antivirals. We will discuss the direction of future therapies, with strategies for shorter durations of therapy and new all-oral combinations in the pipeline.

Review article: the efficacy and safety of daclatasvir in the treatment of chronic hepatitis C virus infection

BACKGROUND

The treatment of hepatitis C virus (HCV) has evolved dramatically after the introduction of direct acting anti-virals. NS5A protein plays an important role in HCV replication and is an attractive target for drug development.

AIM

To review clinical studies on the efficacy and safety of direct-acting anti-virals regimens containing daclastavir, an NS5A inhibitor, in the treatment of chronic hepatitis C.

METHODS

A Medline search was undertaken to identify relevant literature using search terms including 'daclatasvir', 'HCV treatment' and 'NS5A inhibitors'. Furthermore, we scanned abstracts presented at the recent international meetings in liver disease, viral hepatitis and infectious disease, as well as the reference lists of the review articles to identify publications not retrieved by electronic searches.

RESULTS

Daclatasvir is the first-in-class HCV NS5A inhibitor that has been demonstrated in Phase I-III trials to have a potent anti-viral effect and clinical efficacy across multiple HCV genotypes (GT). Daclastavir is generally safe and well tolerated, with a low barrier to resistance and low potential for drug-drug interaction. When Daclastavir is added to PEG-IFN/RBV platform, sustained virological response (SVR) rates are increased significantly compared with PEG-IFN/RBV alone. The all-oral combination of Daclastavir/asunaprevir (ASV; protease inhibitor) has high SVR rates against GT1b, but less activity against GT1a. Dual combination of Daclastavir/Sofosbuvir (SOF; nucleotide polymerase inhibitor) and triple combination of Daclastavir/ASV/beclabuvir (BCV; non-nucleoside polymerase inhibitor) have demonstrated >90% SVR rates in both treatment naïve and treatment-experienced patients with GT1. Furthermore, Daclastavir/SOF combination has also demonstrated up to 90% SVR rates in patients with GT3, and in those with human immunodeficiency virus coinfection, cirrhosis and post-transplant HCV recurrence with any GT. Daclastavir/ASV/BCV has primarily demonstrated near 100% SVR rates in patients with GT4.

CONCLUSION

Daclastavir-containing regimens, with or without PEG-IFN, have shown promising results in clinical trials, and present an excellent treatment option for those with chronic HCV and for multiple genotypes.

NS5A Sequence Heterogeneity and Mechanisms of Daclatasvir Resistance in Hepatitis C Virus Genotype 4 Infection

Background. Daclatasvir is an NS5A inhibitor approved for treatment of infection due to hepatitis C virus (HCV) genotypes (GTs) 1–4. To support daclatasvir use in HCV genotype 4 infection, we examined a diverse genotype 4–infected population for HCV genotype 4 subtype prevalence, NS5A polymorphisms at residues associated with daclatasvir resistance (positions 28, 30, 31, or 93), and their effects on daclatasvir activity in vitro and clinically.

Methods. We performed phylogenetic analysis of genotype 4 NS5A sequences from 186 clinical trial patients and 43 sequences from the European HCV database, and susceptibility analyses of NS5A polymorphisms and patient-derived NS5A sequences by using genotype 4 NS5A hybrid genotype 2a replicons.

Results. The clinical trial patients represented 14 genotype 4 subtypes; most prevalent were genotype 4a (55%) and genotype 4d (27%). Daclatasvir 50% effective concentrations for 10 patient-derived NS5A sequences representing diverse phylogenetic clusters were ≤0.080 nM. Most baseline sequences had ≥1 NS5A polymorphism at residues associated with daclatasvir resistance; however, only 3 patients (1.6%) had polymorphisms conferring ≥1000-fold daclatasvir resistance in vitro. Among 46 patients enrolled in daclatasvir trials, all 20 with baseline resistance polymorphisms achieved a sustained virologic response.

Conclusions. Circulating genotype 4 subtypes are genetically diverse. Polymorphisms conferring high-level daclatasvir resistance in vitro are uncommon before therapy, and clinical data suggest that genotype 4 subtype and baseline polymorphisms have minimal impact on responses to daclatasvir-containing regimens.

Beclabuvir for the treatment of hepatitis C

INTRODUCTION

About 185,000,000 people worldwide are chronically infected with hepatitis C virus (HCV). Currently, the most successful HCV infection antiviral therapies reduce the chance of progression towards the advanced phases of the hepatopathy (liver cirrhosis, hepatocellular carcinoma and death). Recently, however, several new direct-acting antivirals against HCV are available or are in an advanced phase of clinical development.

AREAS COVERED

This review focuses on beclabuvir , an allosteric non-nucleotide inhibitor of HCV polymerase. The article covers its pharmacokinetics, mechanism of action, in addition to its tolerability and safety profile as well as its resistance pattern.

EXPERT OPINION

The pharmacokinetic, efficacy and tolerability profile of beclabuvir, as well as its barrier to resistance, are very favorable. In particular, the combination of beclabuvir with asunaprevir and daclatasvir achieves very high rates of viral eradication (about 90%) in patients infected with HCV genotype 1, which is the most common genotype worldwide. Therefore, beclabuvir represents a powerful weapon against HCV infection and has to be considered an optimal option in tailored IFN-free combinations.

Activins and Follistatin in Chronic Hepatitis C and Its Treatment with Pegylated-Interferon-α Based Therapy

Pegylated-interferon-α based therapy for the treatment of chronic hepatitis C (CHC) is considered suboptimal as not all patients respond to the treatment and it is associated with several side effects that could lead to dose reduction and/or termination of therapy. The currently used markers to monitor the response to treatment are based on viral kinetics and their performance in the prediction of treatment outcome is moderate and does not combine accuracy and their values have several limitations. Hence, the development of new sensitive and specific predictor markers could provide a useful tool for the clinicians and healthcare providers, especially in the new era of interferon-free therapy, for the classification of patients according to their response to the standard therapy and only subscribing the novel directly acting antiviral drugs to those who are anticipated not to respond to the conventional therapy and/or have absolute contraindications for its use. The importance of activins and follistatin in the regulation of immune system, liver biology, and pathology has recently emerged. This review appraises the up-to-date knowledge regarding the role of activins and follistatin in liver biology and immune system and their role in the pathophysiology of CHC.