Showing posts with label HCV research. Show all posts
Showing posts with label HCV research. Show all posts

Friday, April 14, 2017

HCV Infection, Nonalcoholic Steatohepatitis, and Alcoholic Liver Disease in Patient with Cirrhosis or Liver Failure on Waitlist for Liver Transplant

Gastroenterology
April 2017 Volume 152, Issue 5, Pages 1090–1099.e1
HCV Infection, Nonalcoholic Steatohepatitis, and Alcoholic Liver Disease in Patient with Cirrhosis or Liver Failure on Waitlist for Liver Transplant
David Goldberg∗, Correspondence information about the author David Goldberg Email the author David Goldberg , Ivo C. Ditah∗, Kia Saeian, Mona Lalehzari, Andrew Aronsohn, Emmanuel C. Gorospe, Michael Charlton

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Background & Aims
Concurrent to development of more effective drugs for treatment of hepatitis C virus (HCV) infection, there has been an increase in the incidence of nonalcoholic fatty liver disease. Data indicate that liver transplantation prolongs survival times of patient with acute hepatitis associated with alcoholic liver disease (ALD). We compared data on disease prevalence in the population with data from liver transplantation waitlists to evaluate changes in the burden of liver disease in the United States.

Methods
We collected data on the prevalence of HCV from the 2010 and 2013–2014 cycles of the National Health and Nutrition Examination Survey. We also collected data from the HealthCore Integrated Research Database on patients with cirrhosis and chronic liver failure (CLF) from 2006 through 2014, and data on patients who received transplants from the United Network for Organ Sharing from 2003 through 2015. We determined percentages of new waitlist members and transplant recipients with HCV infection, stratified by indication for transplantation, modeling each calendar year as a continuous variable using the Spearman rank correlation, nonparametric test of trends, and linear regression models.

Results
In an analysis of data from the National Health and Nutrition Examination Survey (2013–2014), we found that the proportion of patients with a positive HCV antibody who had a positive HCV RNA was 0.5 (95% confidence interval, 0.42−0.55); this value was significantly lower than in 2010 (0.64; 95% confidence interval, 0.59−0.73) (P = .03). Data from the HealthCore database revealed significant changes (P < .05 for all) over time in percentages of patients with compensated cirrhosis (decreases in percentages of patients with cirrhosis from HCV or ALD, but increase in percentages of patients with cirrhosis from nonalcoholic steatohepatitis [NASH]), CLF (decreases in percentages of patients with CLF from HCV or ALD, with an almost 3-fold increase in percentage of patients with CLF from NASH), and hepatocellular carcinoma (HCC) (decreases in percentages of patients with HCC from HCV or ALD and a small increase in HCC among persons with NASH). Data from the United Network for Organ Sharing revealed that among patients new to the liver transplant waitlist, or undergoing liver transplantation, for CLF, there was a significant decrease in the percentage with HCV infection and increases in percentages of patients with nonalcoholic fatty liver disease or ALD. Among patients new to the liver transplant waitlist or undergoing liver transplantation for HCC, proportions of those with HCV infection, nonalcoholic fatty liver disease, or ALD did not change between 2003 and 2015.

Conclusions
In an analysis of 3 different databases (National Health and Nutrition Examination Survey, HealthCore, and United Network for Organ Sharing), we found the proportion of patients on the liver transplant waitlist or undergoing liver transplantation for chronic HCV infection to be decreasing and fewer patients to have cirrhosis or CLF. However, the percentages of patients on the waitlist or receiving liver transplants for NASH or ALD are increasing, despite different relative burdens of disease among the entire population of patients with cirrhosis
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Wednesday, December 28, 2016

HBV/HCV dual infection impacts viral load, antibody response, and cytokine expression differently from HBV or HCV single infection

HBV/HCV dual infection impacts viral load, antibody response, and cytokine expression differently from HBV or HCV single infection
Fei Chen, Jian Zhang, Bo Wen, Shan Luo, Yingbiao Lin, Wensheng Ou, Fengfan Guo, Ping Tang, Wenpei Liu & Xiaowang Qu

Received:15 July 2016
Accepted:23 November 2016
Published online:23 December 2016

Scientific Reports 6, Article number: 39409 (2016)
doi:10.1038/srep39409
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Abstract
Hepatitis B virus/hepatitis C virus (HBV/HCV) dual infection is common among high-risk individuals. To characterize the virological and immunological features of patients with HBV/HCV dual infection, we enrolled 1,049 individuals who have been identified as injection drug users. Patients were divided into single and dual infection groups according to the serological markers. We found the average HCV RNA level was significantly lower; however, HBV viral load was significantly higher in HBV/HCV dual-infected patients (n = 42) comparing HCV single infection (n = 340) or HBV single infection (n = 136). The level of anti-HBs in patients who experienced spontaneous HBV clearance was higher than that in HCV single-infected patients with HBV spontaneous clearance. The level of anti-HCV E2 in HBV/HCV dual infection was lower than that detected in HCV single infection. Serum levels of IL-6, IL-8, and TNF-α were significantly lower in HBV/HCV dual-infected patients than in patients infected with HBV or HCV alone. Taken together, two viral replications are imbalanced in dual infected patients. The anti-HBs and anti-HCV E2 antibody production were impaired and proinflammatory IL-6, IL-8, and TNF-α also downregulated due to dual infection. These findings will help further understanding the pathogenesis of HBV/HCV dual infection.

Discussion Only
Full Text Available at Nature.

In this study, we found that HBV DNA levels were higher and HCV viral load were lower in HBV/HCV dual infection as compared with HBV or HCV single infection. Our results clearly suggest a competition between HBV and HCV infection when the liver is infected with both viruses, and HBV replication is dominant in dual-infected subjects.

The different HBV and HCV replication levels are typically attributed to direct interference9,11,18. However, we believe that the observed difference in the two viral replications derived from a competition for uninfected hepatocytes rather than from viral interference. It is well known that the prevalence of HBV infection is much higher than that of HCV infection in the Chinese general population16,31. Furthermore, our previous study, which examined HBV and HCV infection patterns between IDUs and the general population using the similar cohort with this study, demonstrated that HBV infections shared similar patterns by IDUs and the general populations, and HCV infection exhibited distinct features between two populations32. From these studies, we infer that most of the patients with HBV/HCV dual infection infected HBV were though perinatal, while some of these patients were infected though injection drug use. However, the study herein shows that HCV was acquired at a later age. Therefore, it is conceivable that the HBV/HCV dual-infected individuals were already infected with HBV before contracting HCV infection. As the majority of the hepatocytes are already infected with HBV, these cells are generally resistant to viral superinfection. Only a small number of hepatocytes are uninfected, which may be available for HCV infection. Besides, HBV has a long-lived nuclear form of its genome (covalently closed circular DNA) that is able to persist in the face of potent inhibition of viral replication. In contrast, HCV does not have a long-lived genome form; HCV is therefore much more susceptible to eradication by potent immunity33. Moreover, a lower HCV level may reflect a small number of HCV-infected cells, which is a possible explanation for the dominant HBV replication in our cohort.

Further to the rationale for our study results is an explanation for the higher HBV DNA levels in the dual-infected patients than in HBV single-infected patients. Patients with HBV single infection, especially those who acquired the infection in adulthood, likely experienced spontaneous viral clearance, and the number of infected cells was significantly reduced as the natural course of the virus progressed. On the other hand, the subjects with dual infection were likely to have been repeatedly infected with HBV during transmission of HCV, leading to more HBV-infected cells despite the ongoing viral clearance. Due to no treatment guidelines for HBV/HCV dual-infection patients, so it is important to determine the “dominant” virus by serological and virological testing prior to initiating therapy. For patients with dominant HCV infection, IFN or pegylated IFN in addition to ribavirin can achieve comparable sustained virus response as expected with HCV monoinfection. For patients with dominant HBV infection, pegylated IFN plus ribavirin and a nucleos(t)ide analog appears to be a feasible option2,34,35,36.

Wiedmann et al. showed that chronic HCV-infected patients tended to have poor HBV vaccination response and low anti-HBs antibody levels25. In this study, we found both the percentage of anti-HBs antibody titers ≥10 mIU/mL and anti-HBs levels in the HCV single-infected patients with HBV spontaneous clearance were lower than that found in patients who experienced spontaneous HBV clearance. The results of various studies revealed that higher concentrations of serum antibody may lead to a longer duration of immunity. The anti-HBs titer correlated to the frequency of IFN-γ-producing HBs-specific T cells. Reports show that HBs-specific T cell and antibody responses did not differ between vaccines and HBV-recovered patients37,38. This finding suggests that greater levels of antibody production would lead to enhanced immunity, and that HCV infection may directly or indirectly influence HBV surface antibody production. Therefore, it is necessary to strengthen the HBV vaccine and increase the monitoring of the anti-HBs antibody levels in the high risk population of HCV infection.

Moorman et al. showed an impaired response to HBV vaccination in chronic HCV-infected patients, which was partly attributed to the upregulated expression of PD-1 and PD-L1 on CD4+ T cells26. We also found that the anti-HCV E2 antibody response was weaker in HBV/HCV dual infection than in HCV single infection. The HCV envelope glycoproteins E2 are codified by E2 genomic regions. Envelope glycoprotein E2 comprises two hypervariable regions. The two hypervariable regions are subject to immune pressure, which leads to the formation of escape mutants. Patients infected with HCV develop a humoral immune response against HCV envelope proteins; therefore, anti-HCV E1 and E2 may have the capability of neutralizing HCV infection39. This finding suggests that HBV infection may negatively impact HCV antibody response. Of great consideration, our findings do not support the suggestion that the upregulation of expression of immune checking molecules was partially responsible for lower anti-HBs or anti-HCV E2 levels in the dual infection, since viral proteins are also expressed in single infection if they inhibited the immune response. We believe that the HBV/HCV dual infection placed a heavier burden on the immune system of the host, and that the antibody production has to deal with two viral infections, which leads to a weak antibody response to each virus.

Pro-inflammatory cytokines such as IL-6, IL-8, and TNF-α are involved in HBV- or HCV-induced liver inflammation and treatment outcomes27,40,41,42,43. The expression levels of these cytokines in HBV/HCV dual infection are unclear. Here, we showed that the serum levels of IL-6, IL-8, and TNF-α expression were significantly lower in HBV/HCV dual infection compared with HCV or HBV single infection, which is consistent with an in vitro study that showed that co-culturing HBV and HCV core proteins with human dendritic cells significantly increased the production of immune-suppressive cytokine, IL-10, and decreased the expression of pro-inflammatory cytokines. IL-6, IL-12, and TNF-α. In addition, the results of this study suggested that viral core proteins can synergistically induce the immune tolerance of dendritic cells and overproduce IL-10, which can inhibit the production of pro-inflammatory cytokines such as IL-6 and TNF-α28.

In summary, our study showed that there likely exists competition for uninfected hepatocytes when the liver is infected with both HBV and HCV. The viral dominance in dual infection was largely determined by the virus that firstly established the infection. Hepatitis B replication was dominant in this cohort because HBV was likely the first to infect the majority of liver cells. In addition, dual infection placed a heavier burden on the immune system of the host and weakened the antibody production capacity, leading to a lower level of protective antibody to each virus. Taken together, our data may contribute to further understanding the biology of viral infection and immune response in patients with a dual infection of HBV and HCV.

Tuesday, November 22, 2016

Hep C Treatment Prognosis Continues to Amaze

American College of Gastroenterology (ACG) 2016 Annual Scientific Meeting


Hep C Treatment Prognosis Continues to Amaze
Damian McNamara
November 22, 2016

LAS VEGAS — Rapid advances in the treatment of hepatitis C have clinicians seeing outcomes they never thought possible, and experts are optimistic that more complex and challenging patients will respond to therapy.

However, treatment choice can be tricky. And caveats are emerging, including reports that direct-acting antivirals used for the treatment of hepatitis C might increase the risk for hepatitis B reactivation and liver cancer in some patients.

But the big picture is one of clinical success. "We know that 95% to 100% of patients treated for hepatitis C can be cured. It's pretty amazing," said Tram Tran, MD, from the Cedars–Sinai Medical Center and the University of California at Los Angeles.

Continue reading @ Medscape

Of Interest
Nov 21, 2016
NATAP ​- Reported by Jules Levin
New HCV Drugs at AASLD
Key presentations of new HCV DAA regimens

Thursday, November 17, 2016

Hepatitis C virus tricks liver cells to sabotage immune defenses

Hepatitis C virus tricks liver cells to sabotage immune defenses 
November 17,2016
Virus induces liver cells to make molecules that inhibit production of a key immune signaling receptor

University of Washington Health Sciences/UW Medicine

The virus that causes hepatitis C protects itself by blocking signals that call up immune defenses in liver cells, according to University of Washington researchers and colleagues reporting Nov. 14 in Nature Medicine.

"The finding helps explain why many patients fail certain drug treatments, and should help develop more effective alternate treatment protocols," said Ram Savan, the study's corresponding author and an assistant professor of immunology in the UW School of Medicine.

Hepatitis C virus is the most common cause of chronic hepatitis and the leading cause of liver cancer in the United States. It is primarily spread through contact with infected blood. Each year, more than 30,000 Americans become infected. As many as 85 percent develop life-long chronic infections. Of these patients, about one in 10 will eventually develop cirrhosis and liver cancer.

In the latest study, lead author Abigail Jarret, now a graduate student at Yale University, and her group showed that hepatitis C virus sabotages the antiviral defenses of liver cells by blunting the effect of key immune proteins called interferons.

When cells become infected, they release interferons. These in turn spur hundreds of genes that generate virus-fighting proteins within the cell. Interferons can even provoke cells to self-destruct to prevent the virus from propagating.

One of these interferons, called interferon-alpha, has been used for many years to treat chronic hepatitis C virus infections, either alone or in concert with an antiviral called ribavirin. These treatments helped many patients get rid of the virus, but the treatment fails to cure more than 60 percent of patients.

Newer, more effective drugs with fewer side effects have now largely replaced interferon-based therapies. However, it was not clear why interferon treatment failed so often. From this study, researchers hypothesized that the virus' ability to evade interferons was related to the cells themselves.

In a previous study, Savan's research team discovered that when hepatitis C virus invades a liver cell, the virus induces the cell to activate two genes -- MYH7 and MYH7B. These genes are usually active only in smooth skeletal muscle and heart cells. Once activated, these genes produce two microRNAs, molecules that can interfere with the production of other proteins.

Savan and his fellow researchers showed that these microRNAs interfered with the cell's production of two interferons. By activating the MYH7 and MYH7B genes, the invading hepatitis C viruses limit liver cells' ability to generate these interferons. The cells are then less able to resist and remove the virus.

The investigators also showed that these virally-induced microRNAs inhibit production of a receptor crucial to the cell's interferon-driven antiviral response.

Thus, these hepatitis C virus-induced microRNAs can blunt liver cell interferon-driven antiviral defenses in two ways, Jarret explained.

First, the virus inhibits the cell's ability to produce its own type III interferons.

Second, it prevents the cells from making the receptors needed in order for type I interferons to be effective.

"This may in part explain why interferon treatments, which harness a type I interferon, fail in so many patients," Jarret said.

This project was funded partly by the National Institutes of Health.

The Nature Medicine article is "Hepatitis-C-virus-induced microRNAs dampen interferon-mediated antiviral signalling."

Wednesday, July 27, 2016

Adding ribavirin to newer DAA regimens does not affect SVR rates in HCV genotype 1 infected persons: results from ERCHIVES

Alimentary Pharmacology & Therapeutics
Early View (Online Version of Record published before inclusion in an issue)

Adding ribavirin to newer DAA regimens does not affect SVR rates in HCV genotype 1 infected persons: results from ERCHIVES
A. A. Butt1,2,3,*, P. Yan1, K. Marks3, O. S. Shaikh1,4, K. E. Sherman5

Version of Record online: 26 JUL 2016
DOI: 10.1111/apt.13748

Background
Ribavirin is a key component of several hepatitis C virus (HCV) treatment regimens. However, its utility in combination with newer directly acting anti-viral agents regimens is unclear.

Aim
To determine the SVR rates with paritaprevir/ritonavir/ombitasvir/dasabuvir (PrOD) regimen ± ribavirin and compare this with sofosbuvir/simeprevir and sofosbuvir/ledipasvir regimens.

Methods
We used Electronically Retrieved Cohort of HCV Infected Veterans (ERCHIVES), a well-established national cohort of HCV-infected Veterans to identify HCV genotype 1 infected persons initiated on the above regimens. We excluded those with HIV coinfection, positive HBsAg and missing HCV RNA.

Results
We identified 1235 persons on PrOD (75.5% ribavirin), 1254 on sofosbuvir/simeprevir (16.9% ribavirin) and 4247 on sofosbuvir/ledipasvir (23.3% ribavirin). Among HCV genotype 1a infected persons, ribavirin was prescribed to 99.2% on PrOD, 18.2% on sofosbuvir/simeprevir and 23.3% on sofosbuvir/ledipasvir. The SVR rates ranged from 92.6% to 100% regardless of the treatment regimen, presence of cirrhosis or HCV subtype, except in PrOD group without ribavirin, HCV genotype 1a without cirrhosis (SVR 80%, N = 5). There were minor, clinically insignificant differences in SVR rates in those treated with or without ribavirin in each of the treatment groups, regardless of presence of cirrhosis at baseline. In multivariable logistic regression analysis, ribavirin use was not associated with achieving SVR in any group.

Conclusions
In HCV genotype 1 infected persons, PrOD, sofosbuvir/simeprevir and sofosbuvir/ledipasvir regimens, are associated with high rates of SVR in actual clinical settings, which are comparable to clinical trials results (except PrOD genotype 1a with cirrhosis where the number was too small). The benefit of adding ribavirin to these regimens in the ERCHIVES treated cohort is not established.

Discussion Only
Full Text Article Available @ Alimentary Pharmacology & Therapeutics

In this large national observational study of HCV infected persons in actual clinical settings, ribavirin use was not associated with any clinically meaningful differences in SVR rates among patients treated with newer DAA regimens. Presence of cirrhosis at baseline, HCV subtype and prior treatment status did not affect these results. Number of HCV genotype 1a infected persons treated with PrOD (without ribavirin) was too small to make any conclusions in this group (n = 6).

Our study demonstrates that treatment for HCV infection with newer oral regimens is associated with high SVR rates in actual clinical settings, and that these rates are comparable to those seen in clinical trials.[23] We have previously shown that treatment with sofosbuvir-based regimens in actual clinical settings is associated with SVR rates similar to clinical trials,[8] and this study provides similar assurance with PrOD regimen in similar settings. To our knowledge, this is among the first and largest study with data from actual clinical settings, that compares the three commonly used newer DAA agents.

Ribavirin was considered an important part of the treatment regimen with pegylated interferon and first generation DAAs. However, its role in all-oral regimens of newer DAAs is less clear. In one recent trial, virological failure was more common without ribavirin than with ribavirin among HCV genotype 1a infected patients but not among those with genotype 1b infection.[10] In another trial, ledipasvir + sofosbuvir + ribavirin for 12 weeks and ledipasvir + sofosbuvir without ribavirin for 24 weeks provided similar SVR12 rates in previous nonresponders with HCV genotype 1 and compensated cirrhosis.[24] Use of ribavirin is associated with significant haematological toxicity and drug–drug interactions, and it is a highly teratogenic agent.[25, 26] In a recent analysis of 1952 patients enrolled in phase III ION clinical trials, treatment-related adverse events were observed in 71% of patients treated with RBV, but in only 45% of patients treated without RBV.[26] While most adverse events were mild in severity and not associated with treatment discontinuation, there is some cost and risk to adding ribavirin to the regimen. Regimens without ribavirin are attractive in such settings.

The strongest and most consistent predictor of achieving SVR was duration of treatment. This is not surprising, and is consistent with numerous previous studies which have assessed patients treated in actual clinical settings.[8, 9] Future studies should assess the role of treatment adherence upon virological outcomes in these patients. Presence of cirrhosis at baseline was associated with a numerically large reduction in SVR rates (37% lower SVR rates for PrOD, 44% for sofosbuvir/simeprevir, 53% for sofosbuvir/ledipasvir), though this did not reach statistical significance in the PrOD group.

The newer treatment regimens remain associated with a low rate of adverse haematological adverse events.[27] Although anaemia was more common in those who received ribavirin, severe (grade 3/4) anaemia remains uncommon overall. In previous studies, we have shown that haematological parameters revert towards baseline after completion of treatment, providing some reassurance regarding the safety of these regimens.[9]

While our study provides new and important clinical information about newer DAA regimens derived from a well-established national database, there are certain limitations that need to be addressed when analysing administrative databases. The information in such databases is collected as part of routine clinical care, and is thus not always collected at rigorously defined time-points during the course of treatment. Given this is an observational study and not a randomized study of ribavirin use, confounding by indication is of concern. Persons who received ribavirin may have been harder to treat; however, in multivariate analysis controlling for these baseline predictors did not reveal a benefit of ribavirin use. Laboratory testing was performed at different laboratories, and subtle differences in results may affect overall results. Definition of cirrhosis was based on a non-invasive clinical marker (FIB-4 score), which was based on routine laboratory testing which may have been performed at different time-points prior to baseline. Number of persons in HCV genotype 1a PrOD group was too small (n = 6) to make any conclusions, and clinical trials data suggest that adding ribavirin in genotype 1a patients may be of some benefit.[10] We also did not analyse the role of resistance associated mutations upon virological response rates.

In conclusion, in HCV genotype 1 infected persons, PrOD, sofosbuvir/simeprevir and sofosbuvir/ledipasvir regimens are associated with high rates of SVR in actual clinical settings, which are comparable to those achieved in clinical trials (except PrOD genotype 1a with cirrhosis where number was too small). Addition of ribavirin to the regimen does not appear to enhance SVR rates in a clinically meaningful way, with the caveat that the number of persons in HCV genotype 1a PrOD group was too small to make any conclusions.

  1. Summary
  2. Introduction
  3. Methods
  4. Results
  5. Discussion
  6. Authorship
  7. Acknowledgements
  8. References
  9. Supporting Information

Saturday, January 30, 2016

Chronic hepatitis C: This and the new era of treatment.

*Abstract, discussion and conclusion provided below please, click here to review the full text article. 

World J Hepatol. 2016 Jan 18; 8(2): 92–106.
Published online 2016 Jan 18. doi: 10.4254/wjh.v8.i2.92

Chronic hepatitis C: This and the new era of treatment.
Bertino G1, Ardiri A1, Proiti M1, Rigano G1, Frazzetto E1, Demma S1, Ruggeri MI1, Scuderi L1, Malaguarnera G1, Bertino N1, Rapisarda V1, Di Carlo I1, Toro A1,Salomone F1, Malaguarnera M1, Bertino E1, Malaguarnera M1.

Author information

Abstract
Over the last years it has started a real revolution in the treatment of chronic hepatitis C. This occurred for the availability of direct-acting antiviral agents that allow to reach sustained virologic response in approximately 90% of cases. In the near future further progress will be achieved with the use of pan-genotypic drugs with high efficacy but without side effects.

KEYWORDS:
Boceprevir; Daclatasvir; Dasabuvir; Direct-acting antiviral agents; Faldaprevir; Hepatitis C; Ledipasvir; Nucleoside inhibitors; Ombitasvir; Ritonavir; Simeprevir; Sofosbuvir; Telaprevir

Core tip: This review analyzes the current therapies for chronic hepatitis C and the future challenges of the research. So it tries to give an update on the research of hepatitis C virus (HCV) infection, providing a critical view of the emerging therapies and their impact on the future management of HCV infection. Since novel treatments for HCV infection are highly efficacious but costly, priority should be given to patients with advanced hepatic fibrosis, which is a disease that cannot be deferred.

DISCUSSION AND CONCLUSION 
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Today, it can be anticipated that the future of HCV infection treatment seems very bright after the addition of first-generation HCV PIs as well as SMV and the first-in-kind HCV RNA polymerase inhibitor, ‘‘sofosbuvir’’, in the standard of care (i.e., PEG-IFN/RBV). However, the real success of these drugs is very much dependent on careful monitoring of viral load and resistance, patterns of response to previous treatment, side effects and drug-drug interactions. Moreover, the logical meaning of novel emerging therapies must be to achieve high SVR and thorough clearance of the virus from treated patients. Nevertheless, the triple therapeutic regimens have several limitations. First, concomitant use of PEG-IFN plus RBV is essential to prevent the emergence of viral escape mutants and viral breakthrough during triple therapy. Second, triple therapy becomes less effective in prior null responders to PEG-IFN plus RBV and cannot be administered to patients who are contraindicated for PEG-IFN or RBV. To overcome these limitations, in the near future, many patients will be treated with two or more DAAs with or without IFN-α plus RBV based combination therapies. Currently, the approval of sofosbuvir- and SMV-based IFN-free regimens is an indication in this way. Triple and quadruple treatment regimens including multiple DAAs with or without PEG-IFN and RBV will likely be a suitable option for difficult-to-treat populations and for the prior null responders. All-oral IFN free regimens including drugs with a high genetic barrier to antiviral resistance (e.g., NS5B inhibitors) and high antiviral efficacy (e.g., NS3/4A PIs or NS5A inhibitors) may be a potent option for numerous patients contraindicated for PEG-IFN plus RBV. All oral regimens consisting of daclatasvir plus sofosbuvir once daily presented higher rates of SVR in untreated HCV GT-1, -2 and -3 infected patients and in HCV GT-1 infected patients who had failed previous treatment with PIs. We hope that such combinational treatment strategies will become ‘‘the weapon’’ to treat the majority of HCV infected patients who represent the difficult population (i.e., IL-28 polymorphism, HCV genotypes 1 and 4 subtypes, receipt of RBV, and the emergence of resistant variants) and will be more efficient to access the treatment in the near future. The testing of adenovirus vector based vaccines, which escalate the innate and acquired immune response against the most conserved regions of HCV genome in chimpanzees and humans, may be a promising therapeutic approach against HCV in the near future, although its fate still needs to be exploited fully in diverse HCV populations. One thing must be of special concern is whether the newly developed or being developed DAAs added in triple or quadruple therapies are safer or not than antiretroviral and traditional IFNs. Overall, the achievements in the field of HCV medicines may predict that we are near to complete elimination of HCV disease in the world[140]. The real challenges that our efforts must be directed are: (1) the effectiveness of IFN-free regimens in HCV-3, especially in cirrhotic non-responders; in this setting, combination with PEG-IFN is still possible; (2) the effectiveness of IFN-free regimens in decompensated cirrhosis are scarce in relation to the current correlation data between SVR and clinical outcome (literature confirms that the results of IFN-free regimens are good in compensated cirrhosis even if further clinical development is necessary in certain groups to improve SVR rates); (3) the development of new treatment strategies for patients who show resistance to new drugs; and (4) free-access to care[141]. In fact, many patients with CHC have mild disease and are currently excluded from the interferon-free treatment. In the near future we will inevitably prioritize this category in order to prevent progression to cirrhosis, decompensation and HCC.


Monday, December 7, 2015

HCV genotype 3: a wolf in sheep’s clothing

Journal: Expert Review of Anti-infective Therapy
Editorials

HCV genotype 3: a wolf in sheep’s clothing

DOI:10.1586/14787210.2016.1127757
José-R. Blancoa* & Antonio Rivero-Juarez
1a Infectious Diseases Area. Hospital San Pedro - Center for Biomedical Research of La Rioja (CIBIR) . Piqueras 98, 26006 Logroño , La Rioja ( Spain ).
2b Infectious Diseases Unit. Instituto Maimonides de Investigación Biomédica de Córdoba (IMIBIC) . Hospital Universitario Reina Sofía de Córdoba. Universidad de Córdoba . Avda. Menendez Pidal s/n, 14004 Córdoba , Córdoba ( Spain ).

Publishing models and article dates explained

Received: 16 Sep 2015
Accepted: 30 Nov 2015
Accepted author version posted online: 03 Dec 2015

Keywords: Hepatitis C, Genotype 3, Metabolic syndrome, Hepatocellular carcinoma

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HCV genotype 3: a wolf in sheep’s clothing

"All truths are easy to understand once they are discovered; the point is to discover them". Galileo Galilei"

At present, the hepatitis C virus (HCV) is a major cause of morbidity and mortality affecting over 185 million people worldwide,[1] equivalent to a global prevalence of about 2.5% in 2015. Genotype 3 (HCV G3) is one of the seven recognized genotypes.[2] HCV G3 is the second most common genotype overall and is estimated to account for 54.3 million cases throughout the world (30.1%).[1] Although three-quarters of them occur in South Asia where it is endemic, the 3a subtype is an “epidemic subtype“ widely distributed geographically, probably associated with injecting drug use.[3]

 In the last two years, the history of HCV infection has changed radically with the appearance of the new direct-acting antiviral agents (DAAs).[4] Although HCV G3 was one of those genotypes who achieved a better sustained viral response (SVR) using pegylated interferon and ribavirin (PEG-IFN/Rbv) therapy,[5] the current effectiveness of the new DAAs against HCV G3 leaves a lot to be desired compared with the results obtained with other genotypes.[6] This is a major problem since, compared to other genotypes, HCV G3 is associated with faster progression of fibrosis,[7,8] a greater risk for hepatocellular carcinoma (HCC),[8-10] and a higher mortality.[11] Why is it so pathogenic and resistant to treatment? The reasons for this “aggressiveness” are without doubt multiple, complex and not well known.

First, it is important to remember that the host immune response plays an important role in HCV G3 infection because of its potential to contribute to viral clearance. So, acutely HCV-infected patients are much more likely to spontaneously clear HCV if they are infected with HCV G3 than HCV G1.[12] Indeed, chronically infected HCV G3 patients had higher SVR rates after shorter treatment with PEG-IFN/Rbv therapy when compared to those with chronic HCV G1 infection.[13] One of the possible reasons could be that in monocytic cell and plasmacytoid dendritic cell lines and in macrophages differentiated from monocytes with macrophage colony-stimulating factor, HCV G3 induces greater interferon transcription than either genotype 1a or 1b.[14] However, this apparent benefit may backfire because of the increased rate of fibrosis progression of HCV G3, probably due to the higher non-parenchymal cell transcription of IFN genes following intracellular HCV G3 sensing.[14]

It has been reported previously that HCV G3 is associated with a significantly increased risk of developing cirrhosis and HCC compared to HCV G1, and association that is independent of the patients’ age, diabetes, body mass index, or antiviral treatment.[8] The high viremia observed in HCV G3-infected patients may be a marker of rapid disease damage, reflecting either the inability of the immune system to control the infection or the existence of some escape mechanisms in HCV G3 which prevents the immune system response from being effective.[15]

Secondly, another problem that is not well understood is the interaction between HCV and lipid metabolism.[16] So, HCV G3 selectively interferes with the late cholesterol synthesis pathway,[17] although this interference is resolved after the SVR. Other mechanisms that alter lipid metabolism are increased the novo lipogenesis and the inhibition of mitochondrial fatty acid degradation.[18] At what level of lipid metabolism does HCV G3 work? Is the damage the consequence of the virus or of its proteins in infected hepatocytes? Given that, in previous studies, the variables independently associated with SVR were high LDL levels,[19,20] low HDL levels [19] and statin use,[19] one might think that statins would be a useful option for such patients. Nonetheless, this is not actually the case with HCV G3. In one analysis of patients with HCV 1-3 genotypes who received combination therapy with PEG-IFN/Rbv, the significant impact of statin use was only observed among the HCV G1 patients.[20] Similar findings were reported by Selic Kurincic et al.[21]

Steatosis is a common histologic finding in patients infected by HCV G3, independently of the presence of fibrosis, diabetes, hepatic inflammation, ongoing alcohol abuse, higher body mass index, and older age.[22] Indeed, steatosis in HCV G3 infected patients is not the result of overexpression of genes involved in lipogenesis.[23] The higher rates of hepatic steatosis in HCV G3 patients, even in absence of other metabolic complications, suggest that some specific viral sequences may be involved in the etiology of steatosis.[18] In fact, after reaching SVR, hepatic steatosis in these patients had disappeared.[24,25] Another possible explanation for the high presence of steatosis could be that HCV G3 steatosis induces the liberation of proinflammatory chemokines that increase the recruitment of inflammatory cells to the liver.[14] In support of this idea, the depletion of liver Kupffer cells prevents the development of diet-induced hepatic steatosis and insulin resistance.[26]

It is important to bear in mind that there is a significant correlation between the steatosis score and the titer of intrahepatic HCV RNA in patients with HCV G3, providing virological and some clinical evidence that steatosis is the morphological expression of a viral cytopathic effect in patients infected with this genotype.[27] This finding has important implications, such as lower SVR rates or higher relapse rates after HCV treatment.[28,29] Is steatosis a marker of rapid progression or bad prognosis in HCV G3 infected patients?

Non-alcoholic fatty liver disease (steatosis/steatohepatitis) is similarly recognized as the hepatic manifestation of metabolic syndrome (MS). HCV virus genotype 3 infection increases the risk of insulin resistance and diabetes, probably due to the direct effect of the virus on intracellular insulin signaling.[30] This situation not only increases the cardiovascular risk but also reduces the likelihood of achieving a SVR.[31] Another common manifestation of MS is obesity, a problem that also increases the expression of some inflammatory cytokines and activates several signaling pathways involved in the pathogenesis of insulin resistance.[32] The inflammation may also contribute to the pathogenesis of liver damage.[33] Obesity has also been correlated with a lower SVR rate.[34] Once again, this opens up an interesting way to research the mechanisms involving MS and SVR in these patients. Are insulin resistance and/or obesity indicators of the the existence of an established liver damage, even though we are unable to diagnose it? Is there some symbiotic relationship between the adipocytes and HCV G3 that reduces the efficacy of the DAAs? In view of the higher rates of SVR using the new DAAs, is the presence of MS still important in chronic HCV infection?.[35] Probably not, but there is as yet no concrete answer for this question and so the controversy about steatosis and HCV remains. Valenti et al also reported that the rs738409 genotype, a polymorphism that influences liver fat without affecting insulin resistance and body composition, was associated with severe hepatic steatosis in patients infected with a non-3 HCV genotype, and also with fibrosis stage and cirrhosis (OR = 1.47; P = 0.002).[36] Similarly, Cai et al [37] reported that rs738409 was associated with an increased risk of steatosis in patients infected with a non-3 HCV genotype. These results suggest distinct pathogenic mechanisms in the 3 and non-3 genotypes.

Moving on to the third point, and so concluding this topic, it is necessary to understand the clinical implications of the different HCV G3 subtypes (in other words, immunity, inflammation, prognosis, response to DAAs). This is something we already known for HCV G1a and 1b.[38] At least 10 HCV G3 subtypes have been described so far.[39] Are some of these HCV G3 subtypes able to evade the immune response? Can we expect the same SVR for different subtypes? The correct identification of HCV G3 subtypes would probably be necessary because they are crucial in clinical trials evaluating the new DAAs. No data have so far stratified the response of HCV G3 to the new DAAs, which could be an essential issue that requires further investigation.

In summary, given the aggressiveness of HCV G3, it is increasingly necessary to initiate antiviral treatment as soon as possible in all patients, including those with steatosis and/or MS. In these patients, even those with SVR, continued surveillance is necessary, paying careful attention to patients with cirrhosis. There is no doubt that better knowledge of HCV G3 should be a priority for us all.

Financial & competing interests disclosure
JR Blanco has carried out consulting work for Abbvie, Bristol-Myers Squibb, Gilead Sciences, Janssen, Merck, and ViiV Healthcare; has received compensation for lectures from Abbvie, Bristol-Myers Squibb, Gilead Sciences, Janssen, Merck, and ViiV Healthcare, as well as grants and payments for the development of educational presentations for Gilead Sciences and BristolMyers Squibb. A Rivero-Juarez is the recipient of a Postdoctoral Perfection Grant from Fundación Progreso y Salud, Consejería de Salud y Políticas Sociales, Junta de Andalucia (0024-RH-2013). He has received compensation for lectures from Bristol-Myers Squibb, Janssen, Merck, and ViiV Healthcare.The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. 

References
1. Mohd Hanafiah K, Groeger J, Flaxman AD, Wiersma ST. Global epidemiology of hepatitis C virus infection: new estimates of age-specific antibody to HCV seroprevalence. Hepatology. 2013;57(4):1333-1342.
2. Smith DB, Bukh J, Kuiken C, Muerhoff AS, Rice CM, Stapleton JT, et al. Expanded classification of hepatitis C virus into 7 genotypes and 67 subtypes: updated criteria and genotype assignment web resource. Hepatology. 2014;59(1):318-327.
3. Pybus OG, Cochrane A, Holmes EC, Simmonds P. The hepatitis C virus epidemic among injecting drug users. Infect. Genet. Evol. 2005;5(2):131- 139.
4. Gentile I, Buonomo AR, Zappulo E, Borgia G. Interferon-free therapies for chronic hepatitis C: toward a hepatitis C virus-free world? Expert. Rev. Anti. Infect. Ther. 2014;12(7):763-773.
5. Hoofnagle JH, Seeff LB. Peginterferon and ribavirin for chronic hepatitis C. N. Engl. J. Med. 2006;355(23):2444-2451.
6. AASLD/IDSA HCV Guidance Panel Hepatitis C guidance: AASLD-IDSA recommendations for testing, managing, and treating adults infected with hepatitis C virus. Hepatology. 2015;62(3):932-54.
7. Probst A, Dang T, Bochud M, Egger M, Negro F, Bochud PY. Role of hepatitis C virus genotype 3 in liver fibrosis progression--a systematic review and meta-analysis. J. Viral Hepat. 2011;18(11):745-759.
8. Kanwal F, Kramer JR, Ilyas J, Duan Z, El-Serag HB. HCV genotype 3 is associated with an increased risk of cirrhosis and hepatocellular cancer in a national sample of U.S. Veterans with HCV. Hepatology. 2014;60(1):98- 105.
9. Nkontchou G, Ziol M, Aout M, Lhabadie M, Baazia Y, Mahmoudi A, et al. HCV genotype 3 is associated with a higher hepatocellular carcinoma incidence in patients with ongoing viral C cirrhosis. J. Viral Hepat. 2011;18(10):e516-522.
10. McCombs J, Matsuda T, Tonnu-Mihara I, Saab S, Hines P, L'italien G, et al. The risk of long-term morbidity and mortality in patients with chronic hepatitis C: results from an analysis of data from a Department of Veterans Affairs Clinical Registry. JAMA Intern. Med. 2014;174(2):204-212.
11. van der Meer AJ, Veldt BJ, Feld JJ, Wedemeyer H, Dufour JF, Lammert F, et al. Association between sustained virological response and all-cause mortality among patients with chronic hepatitis C and advanced hepatic fibrosis. JAMA. 2012;308(24):2584-2593.
12. Lehmann M, Meyer MF, Monazahian M, Tillmann HL, Manns MP, Wedemeyer H. High rate of spontaneous clearance of acute hepatitis C virus genotype 3 infection. J. Med. Virol. 2004;73(3):387-391.
13. Hadziyannis SJ, Sette H Jr, Morgan TR, Balan V, Diago M, Marcellin P, et al. Peginterferon-alpha2a and ribavirin combination therapy in chronic hepatitis C: a randomized study of treatment duration and ribavirin dose. Ann. Intern. Med. 2004;140(5):346-355.
14. Mitchell AM, Stone AE, Cheng L, Ballinger K, Edwards MG, Stoddard M, et al. Transmitted/founder hepatitis C viruses induce cell-type- and genotypespecific differences in innate signaling within the liver. MBio. 2015;6(2):e02510.
15. Buti M, Esteban R. Hepatitis C virus genotype 3: a genotype that is not 'easy-to-treat'. Expert Rev. Gastroenterol. Hepatol. 2015;9(3):375-385.
16. Clement S, Peyrou M, Sanchez-Pareja A, Bourgoin L, Ramadori P, Suter D, et al. Down-regulation of phosphatase and tensin homolog by hepatitis C virus core 3a in hepatocytes triggers the formation of large lipid droplets. Hepatology. 2011;54(1):38-49.
17. Clark PJ, Thompson AJ, Vock DM, Kratz LE, Tolun AA, Muir AJ, et al. Hepatitis C virus selectively perturbs the distal cholesterol synthesis pathway in a genotype-specific manner. Hepatology 2012;56(1):49-56.
18. Negro F. Hepatitis C virus-induced steatosis: an overview. Dig Dis. 2010;28(1):294-299.
19. Harrison SA, Rossaro L, Hu KQ, Patel K, Tillmann H, Dhaliwal S, et al. Serum cholesterol and statin use predict virological response to peginterferon and ribavirin therapy. Hepatology 2010;52(3):864-874.
20. Pandya P, Rzouq F, Oni O. Sustained virologic response and other potential genotype-specific roles of statins among patients with hepatitis Crelated chronic liver diseases. Clin. Res. Hepatol. Gastroenterol. 2015;39(5):555-565.
21. Selic Kurincic T, Lesnicar G, Poljak M, Meglic Volkar J, Rajter M, Prah J, et al. Impact of added fluvastatin to standard-of-care treatment on sustained virological response in naive chronic hepatitis C patients infected with genotypes 1 and 3. Intervirology. 2014;57(1):23-30.
22. Leandro G, Mangia A, Hui J, Fabris P, Rubbia-Brandt L, Colloredo G, et al. Relationship between steatosis, inflammation, and fibrosis in chronic hepatitis C: a meta-analysis of individual patient data. Gastroenterology, 2006;130(6):1636-1642. Downloaded by [68.43.174.156] at 12:46 07 December 2015
23. Ryan MC, Desmond PV, Slavin JL, Congiu M. Expression of genes involved in lipogenesis is not increased in patients with HCV genotype 3 in human liver. J. Viral Hepat. 2011;18(1):53-60.
24. Poynard T, Ratziu V, McHutchison J, Manns M, Goodman Z, Zeuzem S, et al. Effect of treatment with peginterferon or interferon alfa-2b and ribavirin on steatosis in patients infected with hepatitis C. Hepatology. 2003;38(1):75-85.
25. Kumar D, Farrell GC, Fung C, George J. Hepatitis C virus genotype 3 is cytopathic to hepatocytes: Reversal of hepatic steatosis after sustained therapeutic response. Hepatology 2002;36(5):1266-1272.
26. Huang W, Metlakunta A, Dedousis N, Zhang P, Sipula I, Dube JJ, et al. Depletion of liver Kupffer cells prevents the development of diet-induced hepatic steatosis and insulin resistance. Diabetes 2010;59(2):347-357.
27. Rubbia-Brandt L, Quadri R, Abid K, Giostra E, Malé PJ, Mentha G, et al. Hepatocyte steatosis is a cytopathic effect of hepatitis C virus genotype 3. J. Hepatol. 2000;33(1):106-115.
28. Aziz H, Gill U, Raza A, Gill ML. Metabolic syndrome is associated with poor treatment response to antiviral therapy in chronic hepatitis C genotype 3 patients. Eur. J. Gastroenterol. Hepatol. 2014;26(5):538-543.
29. Restivo L, Zampino R, Guerrera B, Ruggiero L, Adinolfi LE. Steatosis is the predictor of relapse in HCV genotype 3- but not 2-infected patients treated with 12 weeks of pegylated interferon-alpha-2a plus ribavirin and RVR. J. Viral Hepat. 2012;19(5):346-352.
30. Kawaguchi T, Yoshida T, Harada M, Hisamoto T, Nagao Y, Ide T, et al. Hepatitis C virus down-regulates insulin receptor substrates 1 and 2 through up-regulation of suppressor of cytokine signaling 31. Am. J. Pathol. 2004;165(5):1499-1508. 31. Poustchi H, Negro F, Hui J, Cua IH, Brandt LR, Kench JG, et al. Insulin resistance and response to therapy in patients infected with chronic hepatitis C virus genotypes 2 and 3. J. Hepatol. 2008;48(1):28-34.
32. Chen L, Chen R, Wang H, Liang F. Mechanisms linking inflammation to insulin resistance. Int. J. Endocrinol. 2015;2015:508409.
33. Szabo G, Petrasek J. Inflammasome activation and function in liver disease. Nat. Rev. Gastroenterol. Hepatol. 2015;12(7):387-400.

"
All truths are easy to understand once they are discovered
; the point is to
discover them
"
.
Galileo Galilei

Thursday, September 10, 2015

MODELLING THE HELICASE TO UNDERSTAND HEPATITIS

MODELLING THE HELICASE TO UNDERSTAND HEPATITIS

NS3 BEHAVES LIKE A “CATERPILLAR” AND HELPS THE VIRUS TO REPLICATE

NS3 is an enzyme specific to the hepatitis C virus. If developed, a drug capable of recognizing and selectively attacking it could fight the disease without side effects for the body. However, to be able to develop one we need to know more about the behavior of this important protein in the virus replication process. Some SISSA scientists have provided a detailed and comprehensive view of the behavior of NS3. The study has been published in the journal Nucleic Acids Research.

According to the WHO, a good 140 million people are affected by hepatitis C (3/4 million new cases per year). This is still a subtle disease which, in the event of chronic infection, heavily affects the patients' quality of life and whose complications can lead to death. One of the molecules involved in the reproduction mechanism of the virus in the body is a helicase, NS3, an enzyme that interacts with the RNA (the viral genome, which is not like our DNA) by climbing onto it and helping the pathogen's replication process.



"By knowing in detail how this helicase works, in the future we could try to block the viral replication, and thus stop the disease from proliferating in the body" explains Giovanni Bussi, SISSA professor and among the study authors. NS3 facilitates the work of the polymerases, the molecules that build a replica of the RNA strand, by "opening" and preparing the RNA to the action of the second enzyme. "NS3 crawls along the RNA strand contracting and extending like a caterpillar and, as it does so, it releases the part of the virus to which the polymerase then attaches" explains Andrea Pérez-Villa, SISSA student and first author of the paper. "We decided to analyze this protein because, unlike others, it is only present in the hepatitis C virus. This way, any drug capable of targeting its interaction with the RNA would not damage other proteins, for example, those belonging to the body being attacked by the virus. This means that, theoretically, the drug would have no side effects".

"Our work was based on a computer simulation, starting from the available experimental data", explains Pérez-Villa. So far, crystallography studies succeeded in obtaining a limited number of "images" of NS3, too few to be able to reconstruct the whole process. Based on existing data, Pérez-Villa and Bussi (as well as Maria Darvas, SISSA research scientist who took part in the study) created a model of the protein and had it interact with the viral RNA. But not only that.

"During the process, ATP, the "fuel" utilized by proteins, is consumed. Therefore our simulation also reproduced the system's interaction with ATP and subsequently with ADP, a waste product together with phosphate, after ATP had been utilized" concludes Bussi. So for the first time we provided a detailed description of the process, which will serve as a guide for future steps forward, whether theoretical or experimental.

Thursday, March 12, 2015

Study details microRNA’s role as a double agent during Hep C infection

Study details microRNA’s role as a double agent during Hep C infection
March 12, 2015 | SCIENCE NEWS

In the battle between a cell and a virus, either side may resort to subterfuge. Molecular messages, which control the cellular machinery both sides need, are vulnerable to interception or forgery. New research at Rockefeller University has revealed the unique twist on just such a strategy deployed by the liver-infecting Hepatitis C virus – one that may help explain the progression of liver disease and that the researchers suspect may be found more widely in the world of disease-causing viruses.

Led jointly by Charles Rice, the Maurice R. and Corinne P. Greenberg Professor in Virology and head of the Laboratory of Virology and Infectious Disease and Robert Darnell, Senior Attending Physician, Robert and Harriet Heilbrunn Professor, and head of the Laboratory of Molecular Neuro-oncology, the research is described today (March 12) in Cell. It employed a powerful combination of techniques to map the interactions between the virus and a small piece of genetic material – known as miRNA-122 – that is produced almost exclusively by liver cells, which normally use it to regulate expression of their own genes.


Messages intercepted: When researchers looked at sites on liver cell genomes where the gene-regulating molecule miRNA-122 binds, they found that infected cells (red) had fewer of the normal interactions with miRNA-122 compared to uninfected cells (blue). 

This suggests the virus alters gene expression by sponging up miRNA-122.

“It is well known that once inside a liver cell, the hepatitis C virus must bind to miRNA-122 in order to establish a persistent infection. We found an unanticipated consequence of this interaction: By binding to miRNA-122, the virus acts like a sponge, soaking up these gene-regulating molecules,” says first author Joseph Luna, a graduate student with a joint appointment in the labs. “Our experiments showed this has the effect of skewing gene activity in infected liver cells.”

The fight between an infecting virus and its host is often viewed as proteins fighting like soldiers. And soldiers on both sides must have orders, in this case the genetic information responsible for the production of proteins, Luna explains. This is where miRNA-122 comes in. It is amicroRNA, a type of RNA encoded into the genome for the purpose of turning down the expression of genes. It does this job by guiding a complex of silencing proteins to an RNA transcript of a gene so as to prevent it from being turned into a protein. In this way, miRNA-122 appears to help control a number of normal functions, including cholesterol and iron metabolism, as well as circadian rhythms.

But miRNA-122 is also necessary for hepatitis C virus. Once in a liver cell, the viral RNA binds with miRNA-122, which stabilizes and protects the virus so it can replicate. Over the long term, the hepatitis C virus infections can lead to scarring of the liver and liver cancer.

In order to explore how the hepatitis C virus and miRNA-122 interact and the repercussions for the host liver cells, the researchers used a technique known as cross-linking and immunoprecipitation (CLIP), developed over the past 12 years by the Darnell lab, which was targeted to find Argonaute, one of the proteins involved in silencing. This way, they captured the miRNA-122/Argonaute complexes and the sections of RNA transcript to which they bound. They then sequenced those RNA transcripts to see what genetic instructions they represented.

“One microRNA can have hundreds of targets, but most often studies are driven by anecdotes focused on single interactions. By combining CLIP and RNA sequencing, however, we were able to take a global perspective and map out all of miRNA-122’s interactions across both the viral and infected host genomes,” says study author Robert Darnell, who is also a Howard Hughes Medical Institute Investigator. “The result is a rigorously constructed picture of what is actually going on in the cell.”

Their maps showed a peak in miRNA-122 binding at one end of the viral genome, confirming previous work; miRNA-122 also interacted with the virus in a number of other places, for which the significance is not yet known. When the researchers looked at miRNA-122 interactions in an infected cell, they found lower levels as compared to uninfected cells. What’s more, a look at the expression of genes regulated by miRNA-122 confirmed this microRNA was less active because those genes had higher levels of activity.

“What if chronic low levels of miRNA-122 prompt changes that, over years, contribute to liver damage and cancer? This could be a molecular link between the viral infection and the pathologies associated with hepatitis C,” Luna says. “More work on miRNA-122 targets in hepatitis C-infected patients may clarify why some go on to develop liver cancer and others don’t.”

The hepatitis C virus isn’t the only virus known to alter gene expression in host cells by sponging up their microRNAs. Human cytomegalovirus and herpesvirus saimiri, which infects New World monkeys, employ a similar strategy, producing RNAs specifically to bind up host microRNAs. But, unlike the others, the hepatitis C virus must bind to a microRNA to replicate, and when it does so, the new viral genomes sop up even more miRNA-122, creating a positive feedback.

“We suspect these three cases may just be the tip of the iceberg, that other viruses – perhaps those that replicate much more ferociously – may use similar microRNA-sponging strategies,” study author Charles Rice says. “The techniques we used will make it possible to investigate the use of this strategy in an unbiased way.”

Monday, January 26, 2015

Current and Future HCV Therapy-Do We Still Need Other Anti-HCV Drugs?

Liver International
Current and Future HCV Therapy-Do We Still Need Other Anti-HCV Drugs?

Salvatore Petta, Antonio Craxì
Liver International. 2015;35(s1):4-10.

Abstract and Introduction
Abstract
Eradication of hepatitis C virus (HCV) infection, at least in compensated patients, can help improve the outcomes of liver disease such as cirrhosis, hepatocellular carcinoma (HCC) and liver transplantation, as well as perhaps extra-hepatic complications such as diabetes and cardiovascular risk. In the past few years, the landscape of antiviral therapy has evolved at a breathtaking pace from pegylated interferon (PEG-IFN) plus ribavirin (RBV) (PEG-IFN/RBV) to IFN-based strategies combining direct acting antivirals (DDAs) with PEG-IFN/RBV and finally IFN-free combinations of DAAs. In particular with these most recent developments, treatment regimens have become shorter, safer and even more effective, with a wide range of indications. Nevertheless, research continues and newer antiviral drugs are still under development. At a point when a >90% sustained virological response (SVR) is being claimed with all new available regimens, pharmacological and clinical research should be addressing unresolved areas, such as cases of suboptimal SVR or to increase effectiveness rather than pursuing the development of new 'me-too' drugs. The issues which should be given priority for further development include the following:
  • Improving the results of IFN-free regimens in patients with genotype 3 (HCV-3) infection.
  • Identifying the indications for the treatment in patients with compensated and decompensated cirrhosis.
  • Identifying standardized or personalized backup strategies in patients who do not respond to IFN-free regimens. Finally, because of financial constraints, the high cost of IFN-free strategies prevents their universal use in CHC patients and coverage by national healthcare systems. Thus, efforts must be made to document cost-effectiveness in all clinical scenarios and to develop more affordable IFN-free regimens.
The estimated global prevalence of hepatitis C virus (HCV) infection is 2.2%, corresponding to roughly 130 million HCV-infected individuals worldwide.[1] HCV is one of the main causes of chronic liver disease leading to cirrhosis, hepatocellular carcinoma (HCC) and liver transplantation worldwide. In addition, recent data also suggests that HCV infection increases the risk of morbidity and mortality because of cardiovascular diseases.[2]

A sustained virological response (SVR) is a well validated clinically relevant surrogate outcome in the management of chronically infected HCV patients because viral eradication not only prevents the occurrence of cirrhosis in chronic hepatitis C (CHC),[3] but also the development of its complications in patients with compensated cirrhosis.[4–7] In addition, as observed for HBV-related cirrhosis, SVR might improve the prognosis in patients with decompensated cirrhosis who are or are not awaiting liver transplantation, by compensating liver disease, or by influencing the recurrence of HCV-related cirrhosis and liver failure in the post-transplant setting.

In the past few years, the landscape of antiviral care in patients with chronic HCV has changed quickly; thanks to the increased understanding of the biology of HCV replication and the identification of proteins blocking the key steps. In patients with genotype1 (HCV-1) dual therapy (DT) with peginterferon alfa (PEG-IFN) and ribavirin (RBV) was replaced by PEG-IFN-based triple therapies (TT) with first generation protease inhibitors (PI)-boceprevir (BOC) or telaprevir (TVR). Recently these latter regimens were replaced by simeprevir (SIM) or sofosbuvir (SOF)-based schedules.[8–10] The two latter regimens, combined with PEG-IFN/RBV, resulted in SVR rates ranging from 30% to 92%, also reducing the treatment duration and side-effects. In HCV genotypes 2 and 3 patients, PEG-IFN/RBV strategies were replaced by SOF plus RBV for HCV-2 patients with SVR rates above 90%,[8,11–13] and by SOF plus RBV or SOF plus PEG-IFN/RBV in HCV-3 patients where the addition of PEG-IFN increases SVR rates.[8,11–13] Finally, data on small cohorts of HCV-4 patients showed that compared to DT, TT regimens based on SOF or SIM achieved SVR rates similar to that reported in HCV-1 patients.[8]


At present, drugs registered in Europe include SIM, SOF and Daclatasvir (DAC), which are combined with PEG-IFN/RBV in HCV-1 and HCV-4 patients with the SVR rates mentioned above, by an off-label combination (SOF/SIM or SOF/DAC or DAC/SIM) with/without RBV in pilot studies of small groups of patients, or in combination with RBV in HCV-2 and HCV-3 patients (for SOF only).

Recent clinical trials have shown that all oral IFN-free regimens combining the different DAA–SOF/Ledipasvir(LED) and Paritaprevir(PAR)/Dasabuvir(DAS)/Ombitasvir(OMB) achieve SVR rates ranging from 90% to 100%, independent of the severity of liver damage, the pattern of previous response to DT or first-generation PI, and without significant side-effects.[12–18] These combinations, which should be registered and available in Europe in early 2015, are characterized by a short duration (8–12 weeks), oral administration with a few pills, and by a pangenotypic profile of effectiveness for SOF/LED, but restricted efficacy in HCV-1 (and perhaps HCV-4) for the AbbVie combination.

The next steps in the clinical development of anti-HCV therapy are expected in late 2015–early 2016 with the availability of pangenotypic ultrarapid (4–8 weeks) single pill regimens such as Grazoprevir/MK8742, SOF/GS5816, and BMS791325/DAC/Asunaprevir.

These advances have obviously resulted in innovations in IFN-based regimens.[19] They have resulted in SVR rates >90% with well tolerated IFN-free regimens that represent a new challenge for the treatment of HCV-related liver disease, and create new frontiers for tolerability, safety and the consequences of treatment in untreated groups such as those with decompensated cirrhosis waiting or not for liver transplantation. Thus, the key question is whether future developments should focus on new antiviral regimens, or clinical development in as yet unresolved areas? We feel that available and soon to be available drugs are generally extremely effective even if certain issues (Fig. 1) require further study: (i) suboptimal performance in patients with HCV-3; (ii) treatment of patients with compensated and decompensated cirrhosis; (iii) backup strategies in patients who do not respond to IFN-free regimens; (iv) the costs of drugs.

Figure 1.
Hot topics for the treatment of patients with chronic hepatitis C using IFN-free regimens.


The next section of this review will focus on these issues, reporting available data and suggesting future directions for clinical development.

Patients With Genotype 3 Infection are the Most Difficult to Treat With DAAs
When PEG-IFN/RBV was the treatment for HCV, the same regimen was administered to all subjects and patients were defined as easy or difficult to treat according to viral genotype. HCV- 1 and 4 were considered to be difficult-to-treat and 2 and 3 were considered to be easy to treat.[20] The SVR rates in the latter group were above 80% with shorter treatment.

The availability of IFN-free regimens has confirmed that HCV-2 patients are easy to treat while the paradigm for HCV-3 patients has been reversed compared to 'older, difficult-to-treat' HCV-1 patients. In fact, today with available DAAs, patients with HCV-3 are the most difficult to treat patients (Fig. 2). Results with an IFN-free regimen in HCV-3 patients were initially very encouraging in a small phase II study showing that 12-weeks of SOF/RBV resulted in an SVR in all HCV-2 and 3 patients.[21] In other promising preliminary results, large phase III studies in HCV-2 and 3 treatment-naïve (Fission),[8] experienced (Fusion),[11] and IFN intolerant or unwilling patients (Positron),[8] were begun to assess the effectiveness of 12–16 weeks of SOF/RBV. Overall, these studies have shown that surprisingly, while 12 weeks of SOF/RBV resulted in an SVR in HCV-2 patients independent of previous exposure to PEG-IFN/RBV and the severity of fibrosis, the latter two factors were significant for HCV-3 patients. Specifically, 12 weeks of therapy in treatment-naïve patients resulted in an SVR in 61% and 34% of non-cirrhotic and cirrhotic patients respectively.[8] Moreover the SVR rates in non-cirrhotic patients were 37% and 63% in experienced patients, in the 12- and 16- week course, respectively, and 19% and 61% in the 12- and 16-week course in non-cirrhotic patients respectively.[8,11] In particular, treatment failures were all related to relapse but not virological breakthrough confirming the high genetic barrier to resistance of SOF. These results suggest that strategies to improve SVR rates with an SOF containing regimen in HCV-3 patients should take into account an extension of prior therapy, or the addition of another anti-HCV drug (DAA or immunomodulator). Extending treatment to 24 weeks of SOF/RBV was evaluated in the Valence trial resulting in an overall SVR rate of 83%.[12,13] In particular, this was the result of higher SVR rates in treatment-naïve (93% and 92% in patients without and with cirrhosis respectively), and experienced patients without cirrhosis (87%) while rates were lower in experienced (61%) patients with cirrhosis. These results identified the difficult- to-treat category of patients and suggested that the SVR could be improved by adding another anti-HCV drug. This hypothesis was tested in two small studies. The Lonestar-2 study tested TT with PegIFN/SOF/RBV for 12 weeks in treatment-experienced HCV-2 and 3 patients.[22] The SVR in HCV-3 patients was 83% with no difference in relation to baseline cirrhosis (SVR 83% vs 83% respectively). The second study tested a combination of DAC/SOF resulting in an SVR of 89% of 18 treatment-naïve patients with HCV-3.[23]



Figure 2.

Treatment strategies in treatment naïve (A) and experienced (B) patients with HCV-3 infection with direct antiviral agents. Results from Fission (8) Fusion (11), Valence (12), Lonestar-2 (22) RCTs and Sulkowski et al. (23).

These data suggest that SOF/PEG-IFN/RBV is the most effective treatment in HCV-3 treatment-experienced patients with cirrhosis, and that this regimen is also as effective in all other HCV-3 patients as a 24 week course of SOF/RBV. Despite these strategies certain unresolved issues remain: (i) the inability to treat patients with advanced cirrhosis using an IFN- based regimen, and (ii) the high cost of a 24- week course of SOF. Thus, further research in DAAs is necessary in patients with HCV-3 to validate available data in larger cohorts and test promising new DAA combinations such as Grazoprevir/MK8742, SOF/GS5816, BMS791325/DAC/Asunaprevir, and others.

Patients With Compensated or Decompensated Cirrhosis are Candidates for IFN-free Regimens
The option of using DAAs and combining them in safe and effective IFN-free regimens extends the landscape of antiviral treatment. This is especially true in patients who are at risk of complications or in whom IFN-containing strategies are contraindicated and for whom an SVR could significantly improve the liver-related prognosis. These patients have advanced fibrosis/compensated cirrhosis or decompensated cirrhosis. Results in the former group can be found in analyses of clinical studies with a low number of patients with advanced fibrosis/cirrhosis, and one study that was specifically designed to evaluate the effectiveness of IFN-free regimens in patients with compensated cirrhosis. The ION-1 and ION 2 trials are phase III clinical studies assessing the effectiveness of SOF/LED for 12- or 24-weeks with and without RBV in HCV-1 treatment-naïve (ION-1)[12,13] or experienced (ION-2)[14] patients. The studies included 865 and 440 patients, respectively, 16% with cirrhosis in the ION-1 and 20% with cirrhosis in the ION-2 study. Even if the low number of patients with cirrhosis included in the studies is taken into account, results showed that there was no significant difference in SVR12 rates among treatment-naïve patients with cirrhosis in any of the different arms (94–100%) and compared to patients without cirrhosis (97–99%). Cure rates in the 12-week arms were slightly lower in treatment-experienced patients with cirrhosis (86% without and 82% with RBV), while all patients with cirrhosis treated for 24 weeks achieved an SVR whatever the regimen. Similar promising results were reported in the COSMOS study assessing the effectiveness of SOF/SIM for 12–24 weeks with and without RBV.[24] In the small subgroup of treatment-naïve/experienced F3-F4 patients (n = 41) the SVR rate ranged from 85% in the 12-week arm to 100% in the 24-week arm, with no obvious impact of the addition of RBV. Overall, these studies showed that oral, IFN-free regimens were effective in patients with cirrhosis, and even suggested an improvement in some cases with longer duration regimens, even if they did not have enough power to identify subgroups of patients with lower SVR rates. The TURQUOISE-II study[16] was designed to assess the effectiveness of PAR/DAS/OMB plus RBV for 12 or 24 weeks in a large cohort of 380 treatment naïve or experienced patients with HCV-1 infection and cirrhosis with/without portal hypertension. This study was discussed recently.[25] SVR rates were 92% (97.5% CI 88–96%) at 12 weeks compared to 96% (CI 93–99%) at 24 weeks. Interestingly HCV-1a non-responder patients were identified as difficult to treat and achieved an SVR of 80% in the 12-week arm compared to 93% in the 24-week arm. This study further confirms that the results of IFN-free regimens are generally good in compensated patients with cirrhosis even if further clinical development is necessary in certain groups to improve SVR rates.

The real challenge of IFN-free regimes is treating patients with decompensated cirrhosis. This issue creates interesting avenues of research on antiviral effectiveness and clinical outcomes. At present there is no conclusive evidence on the effectiveness of antivirals in this difficult clinical setting. The only available recent data reported an SVR rate of 65% in 20 patients with HCV-1 decompensated Child B cirrhosis who received LED/SOF. The remaining 7 patients experienced a virological relapse.[26] These preliminary results must be confirmed and validated, even if they support the notion that the greater the severity of liver disease the lower the SVR rate in IFN-free regimens, probably because cirrhotic livers are less able to clear or cure infected cells. However, the other key issue in patients with decompensated cirrhosis is whether virological eradication can result in clinical improvement and compensated liver disease with possible removal from liver transplantation waiting lists, as observed in other clinical settings such as alcoholic hepatitis and HBV-related cirrhosis. Data are not available in this clinical setting where IFN is contraindicated, and where RBV can be a risk, and huge clinical advances are expected.

Existing evidence suggests that available and soon-to-be available IFN-free regimens are effective in patients with compensated cirrhosis, even if further clinical studies are necessary to identify difficult to treat patients (HCV-1a cirrhosis? cirrhotic non-responders?) requiring longer treatment and/or the addition of another DAA with/without RBV. On the other hand, data are needed in patients with decompensated cirrhosis, where the history of DAA-based regimens has barely begun.

Other areas of research in patients with cirrhosis are the use of RBV, and in particular, identifying clinical settings where RBV improves SVR, and finally, safety issues. Data on the safety of IFN-free regimens in patients with cirrhosis are only available for certain combinations and in patients with well-compensated disease. However, the impact of these drugs in patients with compensated cirrhosis – with older disease and co-morbidities – as well as in patients with decompensated liver disease must be evaluated.

Backup Strategies for Failure of DAAs: New Generation DAAs or IFN/RBV ?
The high number of HCV-1 patients treated with TVR or BOC-based TT in phase II and III clinical trials and then in clinical practice, has generated a corresponding proportion of patients with HCV variants resistant to NS3–4A protease inhibitors. With the introduction of IFN-based or IFN-free regimens with new generation DAAs the presence of patients with multidrug resistant viral populations is expected. Thus, the clinical relevance of response to other antiviral strategies has not been sufficiently studied and data are limited. However, the lower SVR rates observed in HCV-1a patients with the Q80K substitution treated with SIM-based therapy suggests that this issue must be carefully evaluated.[9,10]

Observational data on the failure of first generation PI have shown that viral populations resistant to NS3-4A protease inhibitors progressively decline, replaced by wild-type viruses within a few months after treatment withdrawal. These encouraging experimental results were confirmed clinically in a preliminary study showing high SVR rates in patients who did not respond to TVR or BOC TT when there were retreated with IFN-free regimens. Specifically, a 24-week course of SOF/DAC with/without RBV resulted in an SVR in 40/41 patients who failed TVR-based TT.[23] The LONESTAR-1 study[27] tested the effectiveness of 12 weeks of SOF/LED with/without RBV in 40 HCV-1 CHC patients who did not respond to first generation PI, 22 of them with cirrhosis. The authors reported SVR rates of 95% and 100% in the arms without and with RBV respectively.
Results in patients who did respond to IFN plus new generation DAAs vary. Nineteen HCV-1 patients from the ELECTRON-1 study who relapsed after SOF TT were retreated with 12 weeks of SOF/LED and all of them achieved an SVR.[26] On the other hand, HCV-1 patients who did not respond to PEG-IFN/RBV + an investigational PI with/without LED or tegobuvir, achieved an SVR rate of 74%.[28] Most of these patients (90%) carried at least 1 resistance associated variant.
Finally, clinical trials have shown that IFN-free regimens combining more DAAs are highly effective, and that virological failures because of breakthrough or relapse with resistant viruses are rare due to the high resistance barriers. Nevertheless, it should be remembered that: (i) viral populations harbouring resistance to NS5A protease inhibitors may persist for many years after treatment is discontinued and that the clinical significance of this is unknown for new combinations; (ii) the development of viral strains resistant to DAAs is expected to increase in clinical practice because of cases of suboptimal adherence to therapy; and (iii) until now studies evaluating escape strategies for unsuccessful IFN-free regimens have not been performed.

Although results are encouraging and suggest that IFN-free regimens are highly effective in cases of failure with BOC or TVR, further efforts are needed to identify standardized or personalized approaches in patients who do not achieve an SVR even with IFN-based or IFN-free new generation DAA combinations. For this, different approaches should be tested, such as careful assessment of virological strains, extending therapy, and/or adding PEG-IFN and/or RBV to modulate the immune system.

The issue of the cost: careful cost-effectiveness analyses needed
The rapid change in the landscape of antiviral therapy has resulted in an increase in the number of available molecules and significantly better results as well as a significant increase in the cost of drugs. Specifically, the cost of one course of antiviral therapy increased from approximately €10 000–15 000 for DT, to €30 000 for IFN-based first-generation PI therapy and €60 000 with SOF TT. In particular pricing of IFN-free regimens is not yet available, but the cost of the combination of SOF with SIM is approximately €120 000. This raises the key question of whether the application of a universal IFN-free strategy by national healthcare systems is viable in all HCV-1 CHC patients. To answer this question, assessment of the price of a course of antiviral therapy must take into account the cost of drugs, the effectiveness of the treatment strategy, and both direct and indirect costs of the management of side-effects related to drugs. In this way, we can accurately calculate the real cost of achieving an SVR. However, to assess the cost-effectiveness of a therapeutic strategy, its impact on the natural history of the disease and on the costs of managing the disease over time must also be evaluated. For this, the incremental cost-effectiveness ratio for life-years gained or for quality adjusted life years are the markers used. Two recent cost-effectiveness analyses of IFN-free regimens were published for CHC patients with contrasting results.[29,30] Differences in the results of these analyses were due to the estimated pricing of IFN-free regimens and the different comparison arms. Younossi et al.[29] simulated an unrealistic scenario in which the price of the IFN-free regimen was the same as IFN-based first-generation PI which generated a universal cost-effectiveness of IFN-free therapy. On the other hand, Deuffic-Burban et al.[30] developed a more realistic model in which IFN-free treatment was twice as expensive as IFN-based second generation DAAs. This model resulted in the lack of cost-effectiveness of a full IFN-free scenario. However, although the proposed analyses are useful for decision-making and for negotiation of the price of newer IFN-free regimens, the clinical value and ethical impact of treatment should not be unduly influenced by an economic analysis. In other words, availability of highly effective, short duration well tolerated treatment regimens, make them preferable for all patients, from those with advanced disease to those with mild liver damage. Although pricing and cost-effectiveness analyses provide information on IFN-free cost-effectiveness in all clinical scenarios, they cannot determine which patients should receive IFN-free and IFN-based strategies. In resource-limited settings a priority-based treatment plan must be designed where patients at high risk of the complications of liver disease are treated first while those with milder disease can be deferred while undergoing periodic re-evaluation of liver damage.

Conclusions
The availability of short duration, safe and highly effective regimens has created new challenges in the treatment of patients with HCV infection, and especially in groups in which the SVR was low with prior therapies, or in which IFN-based strategies were contraindicated. Despite the optimism for the near future, certain areas require further evaluation to make IFN-free regimens effective in all patients. Finally, efforts should be made to make IFN-free cost-effective in all clinical scenarios and accessible to all patients.

Source-Medscape