Ribavirin treatment for patients with chronic hepatitis C: results of a placebo-controlled study

The Overview of Potential Antiviral Bioactive Compounds in Poxviruses

Poxviruses belong to the family of double-stranded DNA viruses, and it is pathogenic for humans and spread worldwide. These viruses cause infections and various diseases in human. So, it is required to develop new drugs for the treatment of smallpox or other poxvirus infections. Very few potential compounds for the treatment of poxvirus such as smallpox, chickenpox, and monkeypox have been reported. Most of the compounds has used as vaccines. Cidofovir is most commonly used as a vaccine for the treatment of poxviruses. There are no phytochemicals reported for the treatment of poxviruses. Very few phytochemicals are under investigation for the treatment of poxviruses.

Efficacy and Safety of Sofosbuvir/Velpatasvir Plus Ribavirin in Patients with Hepatitis C Virus-Related Decompensated Cirrhosis

A fixed-dose combination of sofosbuvir/velpatasvir (SOF/VEL) plus weight-based ribavirin (RBV) for 12 weeks is recommended for the treatment of patients with hepatitis C virus (HCV)-associated decompensated cirrhosis. However, large global studies, while confirming the effectiveness of SOF/VEL in a broad range of patients, often exclude these patients. This Phase 2, single-arm, open-label study in adult patients with HCV-associated decompensated cirrhosis in France and the USA aimed to provide further data on the safety and efficacy of SOF/VEL plus RBV for 12 weeks in this population. Patients were treated with a fixed-dose combination of SOF 400 mg/VEL 100 mg plus weight-based RBV once daily for 12 weeks. The inclusion criteria were chronic HCV infection (≥6 months), quantifiable HCV RNA at screening, Child-Turcotte-Pugh class B or C cirrhosis, and liver imaging within 6 months of Day 1 to exclude hepatocellular carcinoma. Among 32 patients who initiated treatment, 78.1% achieved sustained virologic response 12 weeks after the end of treatment (SVR12). Failure to achieve SVR12 was due to non-virologic reasons (investigator discretion, n = 1; death, n = 6). All 25 patients in the per-protocol population achieved SVR12 and all but one achieved sustained virologic response 24 weeks after the end of treatment. Adverse events (AEs) were as expected for a patient population with advanced liver disease. All Grade 3-4 and serious AEs and deaths were deemed unrelated to treatment. In patients with HCV-associated decompensated cirrhosis, SOF/VEL plus RBV achieved high SVR12 rates and was generally well tolerated.

Decade of optimizing therapy with direct-acting antiviral drugs and the changing profile of patients with chronic hepatitis C

Chronic infection with the hepatitis C virus (HCV) remains a major health problem affecting approximately 58 million people worldwide. In the era of interferon (IFN)-based regimens, patients particularly infected with genotypes 1 and 4 achieved a low response rate. The implementation of direct-acting antivirals changed the landscape of HCV treatment. The increase in effectiveness provided us with the hope of eliminating HCV as a significant public threat by 2030. In the following years, there was an observed improvement in the treatment of HCV with genotype-specific regimens and highly effective pangenotypic options that are the most recent stage of the revolution. The optimization of therapy was accompanied by changes in the patient profile from the beginning of the IFN-free era over time. Patients treated with antiviral therapies were younger in successive periods, less burdened with comorbidities and comedications, more frequently treatment-naïve and had less advanced liver disease. Before the IFN-free era, specific subpopulations such as patients with HCV/HIV coinfection, those with a history of previous treatment, patients with renal impairment or with cirrhosis had lower chances for a virologic response. Currently, these populations should no longer be considered difficult to treat. Despite the high effectiveness of HCV therapy, there is a small percentage of patients with treatment failure. However, they can be effectively retreated with pangenotypic rescue regimens.

Synthetic 1,2,4-triazole-3-carboxamides Induce Cell Cycle Arrest and Apoptosis in Leukemia Cells

BACKGROUND

A number of studies demonstrate the efficacy of ribavirin against various cancer types in in vitro and in vivo models. However, ribavirin induces the development of multiple side effects, suggesting a high demand for ribavirin analogues with improved therapeutic indexes.

OBJECTIVE

This study was focused on the analysis of ribavirin, its aglycon 1,2,4-triazole-3-carboxamide, and several of its derivatives activities in blood cancer cells in vitro.

METHODS

Four 1,2,4-triazole-3-carboxamide derivatives were designed and synthesized. Antiproliferative effects were evaluated in chronic myeloid leukemia cells К562 and acute lymphoblastic leukemia cells CCRF-SB as well as in the cells of whole blood mononuclear fraction of healthy volunteers by cell counting using the trypan blue exclusion method. Cell cycle distribution and apoptosis under the influence of the compounds were analyzed by flow cytometry with PI staining, and then apoptosis data were confirmed by Western blot analysis for PARP1 and caspase-3 cleavage.

RESULTS

We demonstrated the significant antiproliferative effect of 5-(tetrahydropyran-2-yl)-1,2,4-triazole-3- carboxamide and 1-(tetrahydropyran-2-yl)-1,2,4-triazol-3-carboxamide in leukemia cell lines in vitro in comparison to non-transformed monocytes, providing the rationale for further studies of 1,2,4-triazole-3-carboxamide derivatives as anti-leukemia drugs.

CONCLUSION

These results implied that the 1,2,4-triazole-3-carboxamide derivatives exhibited their antiproliferative activities by induction of cell cycle arrest. Consequently, 5-(tetrahydropyran-2-yl)-1,2,4-triazole-3-carboxamide and 1-(tetrahydrofuran-2-yl)-1,2,4-triazol-3-carboxamide may present antimetabolites with potential anticancer efficacy.

Diagnostic performance of dual-energy computed tomography for HCC after transarterial chemoembolization: Utility of virtual unenhanced and low keV virtual monochromatic images

The purpose of this study is to evaluate the usefulness of virtual unenhanced (VUE) and low keV virtual monochromatic images (VMI) for diagnosing viable hepatocellular carcinomas (HCC) after transarterial chemoembolization (TACE). This retrospective study included 53 patients with suspected viable HCC after TACE who underwent multiphasic liver computed tomography including true unenhanced (TUE) phase and conventional (CV) enhanced phases on a dual-energy scanner. VUE images, 40 keV and 55 keV VMIs of enhanced phases were reconstructed using dual-energy computed tomography data. For every patient, six combination image sets (TUE-CV; TUE-55; TUE-40; VUE-CV; VUE-55; VUE-40) were evaluated by two readers and compared with the reference standard.There was no statistically significant difference (P > .05) in sensitivity or specificity among all image combinations. In most combinations, interobserver agreements were almost perfect. The diagnostic odds ratio showed a higher trend in combinations with conventional images. Currently, with regards to diagnostic performance, liver computed tomography including TUE and CV enhanced phases is recommended for tumor surveillance after TACE because VUE and VMIs do not have a distinct advantage compared to conventional images.

The Pan-ErbB tyrosine kinase inhibitor afatinib inhibits multiple steps of the mammarenavirus life cycle

The mammarenavirus Lassa virus (LASV) causes a life-threatening acute febrile disease, Lassa fever (LF). To date, no US Food and Drug Administration (FDA)-licensed medical countermeasures against LASV are available. This underscores the need for the development of novel anti-LASV drugs. Here, we screen an FDA-approved drug library to identify novel anti-LASV drug candidates using an infectious-free cell line expressing a functional LASV ribonucleoprotein (vRNP), where levels of vRNP-directed reporter gene expression serve as a surrogate for vRNP activity. Our screen identified the pan-ErbB tyrosine kinase inhibitor afatinib as a potent inhibitor of LASV vRNP activity. Afatinib inhibited multiplication of lymphocytic choriomeningitis virus (LCMV) a mammarenavirus closely related to LASV. Cell-based assays revealed that afatinib inhibited multiple steps of the LASV and LCMV life cycles. Afatinib also inhibited multiplication of Junín virus vaccine strain Candid#1, indicating that afatinib can have antiviral activity against a broad range of human pathogenic mammarenaviruses.

A small stem-loop-forming region within the 3'-UTR of a non-polyadenylated LCMV mRNA promotes translation

Mammalian arenavirus (mammarenavirus) mRNAs are characterized by 5′-capped and 3′-nonpolyadenylated untranslated regions (UTRs). We previously reported that the nonpolyadenylated 3′-UTR of viral mRNA (vmRNA), which is derived from the noncoding intergenic region (IGR), regulates viral protein levels at the posttranscriptional level. This finding provided the basis for the development of novel live-attenuated vaccines (LAVs) against human pathogenic mammarenaviruses. Detailed information about the roles of specific vmRNA 3′-UTR sequences in controlling translation efficiency will help in understanding the mechanism underlying attenuation by IGR manipulations. Here, we characterize the roles of cis-acting mRNA regulatory sequences of a prototypic mammarenavirus, lymphocytic choriomeningitis virus (LCMV), in modulating translational efficiency. Using in vitro transcribed RNA mimics encoding a reporter gene, we demonstrate that the 3′-UTR of nucleoprotein (NP) mRNA without a poly(A) tail promotes translation in a poly(A)-binding protein-independent manner. Comparison with the 3′-UTR of glycoprotein precursor mRNA, which is translated less efficiently, revealed that a 10-nucleotide sequence proximal to the NP open reading frame is essential for promoting translation. Modification of this 10-nucleotide sequence also impacted reporter gene expression in recombinant LCMV. Our findings will enable rational design of the 10-nucleotide sequence to further improve our mammarenavirus LAV candidates and to develop a novel LCMV vector capable of controlling foreign gene expression.

Ribavirin as a curative and prophylactic agent against foot and mouth disease virus infection in C57BL/6 suckling and adult mice model

Despite the availability of control measures for foot-and-mouth disease (FMD), the application of antiviral agents is imperative due to certain limitations in the prevention and control of FMD. This study pertains to systematic in vivo investigation of ribavirin as a prophylactic/curative agent, both in suckling and adult C57BL/6 mice against foot-and-mouth disease virus (FMDV) infection. In the adult mice, antiviral efficacy was assessed based on standard clinical score, body weight, and viral load. Only 13.33 to 33.33% of adult mice exhibited disease-specific symptoms following treatment and infection and vice versa, respectively, indicating the antiviral efficacy of the ribavirin. Further, the distribution of virus in different vital organs following ribavirin treatment and virus infection, and vice versa using SYBR green-based real-time PCR is reported. In the blood sample, the viral RNA was detected as early as two days post-infection and there was a significant reduction in virus titer (1000 to 10,000-folds) in the treatment groups compared to the infection control group. Animals receiving ribavirin had significantly lower organ virus titers at 2, 4, 6, 9, and 14 days post-challenge (dpc) than placebo-treated. In suckling mice, the treatment groups were 100% protected/cured compared to the control group. Thus, our data demonstrate that ribavirin may provide a feasible therapeutic approach to prevent as well as to treat FMDV infection.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13337-021-00746-8.

Gender-Specific Frequency Distribution of Hepatitis C Virus Genotypes in Punjab province, Pakistan: A Clinically Significant Descriptive Cross-Sectional Study

Background: Hepatitis C virus (HCV) is the major cause of liver cirrhosis, chronic liver disease, and hepatocellular carcinoma. More than 10 million individuals are living with HCV infection in Pakistan. Due to unawareness, very little information is known about HCV genotype occurrence in Punjab, the largest province of Pakistan. Identification of HCV genotype is very important for HCV treatment because different genotypes of HCV respond differently to antiviral therapy.

Objective: The purpose of this research was to determine the distribution frequency of different HCV genotypes in the Punjab province and to demonstrate the distribution pattern of HCV genotypes in different age groups and sexes.

Materials and Methods: In this study, we performed HCV genotyping of 3692 samples collected from different sites of the Punjab province, Pakistan. Among 3692 samples, 1755 (47.5%) were males and 1937 (52.4%) were females.

Results: A total of 3692 samples were subjected to HCV genotyping and 2977 (81%) patients were genotyped successfully, whereas 715 (19%) patients were found to be HCV not detected. Our study demonstrated that among typeable genotypes, 3a constituted 2582 (69.9%) patients followed by 1a (n = 280) 7.5%, 1b (n = 64) 1.7%, 2a (n = 6) 0.16%, genotype 4 (n = 10) 0.27%, 3+4 (n = 2) 0.56%, 1a+2a (n = 11) 0.29%, 1b+2a (n = 1) 0.02%, 1a+1b (n = 1) 0.02%, and 1a+1b+3 (n = 1) 0.02% patients. HCV genotype distribution was evaluated gender wise and in different age groups like 0-12, 13-18, 19-59, and >60 years. All the HCV genotypes were equally distributed among men and women. The most affected age group was 19-59 years as compared to other age groups.

Conclusion: The most frequently distributed HCV genotype in Punjab was found to be genotype 3a followed by genotype 1a, and only 0.94% of infected patients had a mixed genotype infection. Genotype 1a was found to be increasing significantly in the studied population. With these results, it can be assumed that genotype 3a may be replaced by genotype 1a with the passage of time. If this happens, this situation will be challenging in terms of antiviral therapy.

Mutations Identified in the Hepatitis C Virus (HCV) Polymerase of Patients with Chronic HCV Treated with Ribavirin Cause Resistance and Affect Viral Replication Fidelity

Ribavirin has been used for 25 years to treat patients with chronic hepatitis C virus (HCV) infection; however, its antiviral mechanism of action remains unclear. Here, we studied virus evolution in a subset of samples from a randomized 24-week trial of ribavirin monotherapy versus placebo in chronic HCV patients, as well as the viral resistance mechanisms of the observed ribavirin-associated mutations in cell culture. Thus, we performed next-generation sequencing of the full-length coding sequences of HCV recovered from patients at weeks 0, 12, 20, 32 and 40 and analyzed novel single nucleotide polymorphisms (SNPs), diversity, and mutation-linkage. At week 20, increased genetic diversity was observed in 5 ribavirin-treated compared to 4 placebo-treated HCV patients due to new synonymous SNPs, particularly G-to-A and C-to-U ribavirin-associated transitions. Moreover, emergence of 14 nonsynonymous SNPs in HCV nonstructural 5B (NS5B) occurred in treated patients, but not in placebo controls. Most substitutions located close to the NS5B polymerase nucleotide entry site. Linkage analysis showed that putative resistance mutations were found in the majority of genomes in ribavirin-treated patients. Identified NS5B mutations from genotype 3a patients were further introduced into the genotype 3a cell-culture-adapted DBN strain for studies in Huh7.5 cells. Specific NS5B substitutions, including DBN-D148N+I363V, DBN-A150V+I363V, and DBN-T227S+S183P, conferred resistance to ribavirin in long-term cell culture treatment, possibly by reducing the HCV polymerase error rate. In conclusion, prolonged exposure of HCV to ribavirin in chronic hepatitis C patients induces NS5B resistance mutations leading to increased polymerase fidelity, which could be one mechanism for ribavirin resistance.

Sofosbuvir plus ribavirin is tolerable and effective even in elderly patients 75-years-old and over

BACKGROUND

Although clinical use of sofosbuvir plus ribavirin has been approved for patients infected with genotype 2 hepatitis C virus, patients ≥ 75-years-old have not been included in previous clinical trials.

AIM

To evaluate the real-world safety and efficacy of sofosbuvir plus ribavirin for elderly patients (≥ 75-years-old) compared to nonelderly patients, we conducted a post-marketing prospective cohort study.

METHODS

We treated 265 patients with genotype 2 hepatitis C virus using standard approved doses of sofosbuvir (400 mg/d) plus ribavirin adjusted by body weight, administered orally for 12 wk.

RESULTS

Sustained virological response rates for the overall cohort, patients < 65-years-old, ≥ 65-years-old but < 75-years-old, and ≥ 75-years-old were 97% (258/265), 98% (93/95), 97% (84/87), and 98% (81/83), respectively (P = 0.842). Logistic regression analyses identified history of hepatocellular carcinoma treatment and alpha-fetoprotein as factors significantly associated with sustained virological response. Alpha-fetoprotein was the only independent factor identified. Sustained virological response rate was significantly lower for patients with hepatocellular carcinoma treatment (91%) than for patients without history of hepatocellular carcinoma treatment (98%, P = 0.004). One patient (0.4%) discontinued treatment due to drug-induced pneumonia. Dose reduction or interruption of ribavirin was required for 12.1% (32/265) of patients because of anemia, including 7.7% (14/182) of patients < 75-years-old and 21.7% (18/83) of patients ≥ 75-years-old (P = 0.002).

CONCLUSION

Although ribavirin dose reduction or interruption was required with advanced age, sofosbuvir plus ribavirin appears tolerable and highly effective even in patients ≥ 75-years-old.

Possible therapeutic agents for COVID-19: a comprehensive review

INTRODUCTION

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has emerged in China. There are no available vaccines or antiviral drugs for COVID-19 patients. Herein, we represented possible therapeutic agents that may stand as a potential therapy against COVID-19.

AREAS COVERED

We searched PubMed, Google Scholar, and clinicaltrials.gov for relevant papers. We showed some agents with potentially favorable efficacy, acceptable safety as well as good pharmacokinetic profiles. Several therapies are under assessment to evaluate their efficacy and safety for COVID-19. However, some drugs were withdrawn due to their side effects after demonstrating some clinical efficacy. Indeed, the most effective therapies could be organ function support, convalescent plasma, anticoagulants, and immune as well as antiviral therapies, especially anti-influenza drugs due to the similarities between respiratory viruses regarding viral entry, uncoating, and replication. We encourage giving more attention to favipiravir, remdesivir, and measles vaccine.

EXPERT OPINION

A combination, at least dual or even triple therapy, of the aforementioned efficacious and safe therapies is greatly recommended for COVID-19. Further, patients should have a routine assessment for their coagulation and bleeding profiles as well as their inflammatory and cytokine concentrations.

Paediatric hepatitis C virus infection and its treatment: Present, past, and future

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease in the world. It is a challenging medico-social problem in the paediatric population. High HCV infection rates are reported in low and middle incomes countries. From the health economic point of view treatment of hepatitis C virus (HCV) with subsequent virus eradication is very effective as it eliminates the long-term sequelae of untreated or maltreated HCV. In this review we summarize the updates and highlight the historical approach of treatment of chronic HCV infection in children in the new era of directly acting antiviral (DAA) agents.

Ribavirin inhibition of cell-culture infectious hepatitis C genotype 1-3 viruses is strain-dependent

Ribavirin remains relevant for successful treatment of chronic hepatitis C virus (HCV) infections in low-income settings, as well as for therapy of difficult-to-treat HCV patients. We studied the effect of ribavirin against cell-culture adapted HCV of genotypes 1, 2 and 3, representing ~80% of global infections. TNcc(1a) was the most sensitive to ribavirin, while J6/JFH1(2a) was the most resistant. EC₅₀s ranged from 21 μM (95%CI: 20-22 μM) to 189 μM (95%CI: 173-207 μM). Substitutions at position 415 of NS5B resulted in little or no change to ribavirin sensitivity (0.7-0.9 fold) but conferred moderate drug resistance during extended treatment of genotype 1 (1.8-fold). NS5A and NS5B sequences could alter ribavirin sensitivity 2-4-fold, although their contribution was not simply additive. Finally, we detected limited accumulation of mutations associated with ribavirin treatment. Our findings show that the antiviral effect of ribavirin on HCV is strain-dependent and is influenced by the specific sequence of multiple HCV nonstructural proteins.

Meta-Analysis of Grazoprevir plus Elbasvir for Treatment of Hepatitis C Virus Genotype 1 Infection

BACKGROUND AND AIM

Grazoprevir is an NS3/4A protease inhibitor (PI), while elbasvir is an NS5A inhibitor. We performed this meta-analysis to directly compare grazoprevir plus elbasvir and ribavirin regimen vs. grazoprevir and elbasvir without ribavirin in the treatment of hepatitis C virus genotype 1 infection and to precisely evaluate the efficacy of the latter regimen in cirrhotic, IL28 CC genotype patients and those coinfected with human immunodeficiency virus.

MATERIAL AND METHODS

A computer literature search of PubMed, Scopus, EBSCO, Embase, and Cochrane central was conducted. Studies were screened for eligibility. Sustained virologic response (SVR) rates were pooled using OpenMeta[Analyst] software for windows. A subgroup analysis was performed to stratify the treatment efficacy according to the different baseline characteristics of HCV patients.

RESULTS

Eight randomized controlled trials (n = 1,297 patients) were pooled in the final analysis. The overall SVR rate was 96.6% with 95% CI [95.5% to 98%]. For cirrhotic patients, the SVR rate was 95.7% with 95% CI [93.9% to 97.5%] and for non-cirrhotic patients, the SVR rate was 97% with 95% CI [95.9% to 98.4%]. Furthermore, the addition of ribavirin (RBV) to the treatment regimen did not significantly improve the SVR (RR 1.003, 95% CI [0.944 to 1.065]). The dual regimen was effective in patient populations with NS3 resistance-associated (RAS). However, this regimen achieved lower SVR rates (&lt; 90%) in patients with NS5A RAS.

CONCLUSIONS

We conclude that the 12-week treatment regimen of the fixed dose combination of grazoprevir plus elbasvir achieved high SVR rates in patients with HCV genotype 1 infection. The addition of ribavirin to this regimen did not add a significant benefit.

Inosine Triphosphate Pyrophosphatase Dephosphorylates Ribavirin Triphosphate and Reduced Enzymatic Activity Potentiates Mutagenesis in Hepatitis C Virus

A third of humans carry genetic variants of the ITP pyrophosphatase (ITPase) gene (ITPA) that lead to reduced enzyme activity. Reduced ITPase activity was earlier reported to protect against ribavirin-induced hemolytic anemia and to diminish relapse following ribavirin and interferon therapy for hepatitis C virus (HCV) genotype 2 or 3 infections. While several hypotheses have been put forward to explain the antiviral actions of ribavirin, details regarding the mechanisms of interaction between reduced ITPase activity and ribavirin remain unclear. The in vitro effect of reduced ITPase activity was assessed by means of transfection of hepatocytes (Huh7.5 cells) with a small interfering RNA (siRNA) directed against ITPA or a negative-control siRNA in the presence or absence of ribavirin in an HCV culture system. Low ribavirin concentrations strikingly depleted intracellular GTP levels in HCV-infected hepatocytes whereas higher ribavirin concentrations induced G-to-A and C-to-U single nucleotide substitutions in the HCV genome, with an ensuing reduction of HCV RNA expression and HCV core antigen production. Ribavirin triphosphate (RTP) was dephosphorylated in vitro by recombinant ITPase to a similar extent as ITP, a naturally occurring substrate of ITPase, and reducing ITPA expression in Huh 7.5 cells by siRNA increased intracellular levels of RTP in addition to increasing HCV mutagenesis and reducing progeny virus production. Our results extend the understanding of the biological impact of reduced ITPase activity, demonstrate that RTP is a substrate of ITPase, and may point to personalized ribavirin dosage according to ITPA genotype in addition to novel antiviral strategies.IMPORTANCE This study highlights the multiple modes of action of ribavirin, including depletion of intracellular GTP and increased hepatitis C virus mutagenesis. In cell culture, reduced ITP pyrophosphatase (ITPase) enzyme activity affected the intracellular concentrations of ribavirin triphosphate (RTP) and augmented the impact of ribavirin on the mutation rate and virus production. Additionally, our results imply that RTP, similar to ITP, a naturally occurring substrate of ITPase, is dephosphorylated in vitro by ITPase.

Molecular characterization and clinical epidemiology of HCV in District Dir (Lower), Pakistan

With about 200 million infections globally, Hepatitis C virus (HCV) infection is a major global health threat. The relative prevalence of hepatitis and HCV genotypes/subtypes varies among different geographic regions. Therefore, the present study was conducted to determine the prevalence of hepatitis C and HCV genotypes/subtypes in District Dir (Lower), Pakistan. Blood samples from HCV positive patients were genotyped through multiplex PCR using specific primers for HCV core region. A structured questionnaire was used to obtain information from the patients and data was statistically analyzed for different epidemiological parameters. The molecular evaluation results suggested the prevalence of genotype 3 in this study. The frequency of hepatitis C was found higher in males (P < 0.01). Present study suggests injections received at local clinics as a highly significant mode of HCV transmission to these patients (P < 0.002). These findings might be helpful for clinicians and related health care personnel to assess status of this important disease and highlight the need for more detailed evaluation of this devastating disease in order to frame better treatment strategies.

Ribavirin-induced mutagenesis across the complete open reading frame of hepatitis C virus genotypes 1a and 3a

Ribavirin (RBV) has been used for the last 20 years to treat patients with chronic hepatitis C virus (HCV) infection. This pluripotent drug is believed to induce mutagenesis in HCV RNA. However, for cell-cultured HCV (HCVcc) this phenomenon has only been investigated in genotype 2a recombinants. Here we studied the mutations that developed in HCVcc of genotypes 1a and 3a treated with RBV or ribavirin triphosphate (RBV-TP) compared to non-treated controls. Analysis was performed on the amplified full-length open reading frame (ORF) of recovered viruses following next-generation sequencing and clonal analyses. Compared to non-treated controls, the spread of TNcc(1a) and DBN3acc(3a) HCVcc was delayed by RBV and RBV-TP at concentrations of 40 µM or higher. The delay in HCVcc spread was associated with increased new single-nucleotide polymorphisms (SNP). Significantly higher numbers of new SNP were observed in TNcc(1a) viruses treated with RBV or RBV-TP compared to matched non-treated controls. RBV or RBV-TP treatment led to significantly increased proportions of new G-to-A and C-to-U SNP compared to non-treated TNcc(1a). Clonal analyses confirmed a significantly increased mutation rate in RBV-treated TNcc(1a). Synonymous pairwise distances increased in both viruses across the complete ORF under RBV and RBV-TP treatment compared to controls. Consensus-shifts in single samples of RBV- or RBV-TP-treated TNcc(1a) viruses occurred in proteins E1, p7, NS3 and NS4B. No non-synonymous consensus changes were observed in DBN3acc(3a). This study supports a biased G-to-A and C-to-U mutagenic effect of RBV and RBV-TP throughout the entire ORF of HCV genotypes 1a and 3a.

Crimean-Congo haemorrhagic fever virus: Past, present and future insights for animal modelling and medical countermeasures

Crimean–Congo haemorrhagic fever (CCHF) is a widespread tick‐borne viral zoonosis with a case‐fatality rate ranging from 9% to 50% in humans. Although a licensed vaccine to prevent infection by the CCHF virus (CCHFV) exists, its ability to induce neutralizing antibodies is limited and its efficacy against CCHFV remains undetermined. In addition, controlling CCHF infections by eradication of the tick reservoir has been ineffective, both economically and logistically, and the treatment options for CCHF remain limited. In this review, we first critically discuss the existing animal models to evaluate therapeutics for CCHF. We then review the therapeutic options for CCHF that have been investigated in human cases, followed by investigational drugs that have been evaluated in pre‐clinical studies. We highlight the importance of understanding human prognostic factors in developing an animal model for CCHF that recapitulates hallmarks of human disease and its implication for selecting therapeutic candidates.

A case of a patient infected with a hepatitis C virus genotype 3a multidrug resistant variant in Pakistan

BACKGROUND

Approximately 10 million people in Pakistan are infected with the hepatitis C virus (HCV). Most patients develop chronic hepatitis, with rare cases of spontaneous clearance. However, little is known about multidrug resistant viral variants in Pakistan.

FINDINGS

This case study describes a 47-year-old male diagnosed with chronic HCV genotype 3a infection in 2003. After an initial diagnosis of viral infection, the patient remained treatment naïve for 5 years. He received two therapy cycles of interferon (IFN) plus ribavirin (RBV) in 2007 and 2010, however, he was non-responsive to the therapy. The patient then received an additional two treatment cycles of pegylated IFN α-2b plus RBV (in 2011 and 2013); he was still non-responsive. In 2016, the patient underwent sofosbuvir plus RBV combination therapy, however, the sustained virological response was still not achieved. The host genetic factor was found to be heterozygous guanine and thymine (GT) and cytosine and thymine (CT) genotypes of rs8099917 and rs12979860 polymorphism of IL28B, respectively. Phylogenetic analysis suggests that the resistant variant belong to an out-group and may require triple therapy.

CONCLUSIONS

This is the first case that reports on a HCV-infected individual who was a non-responder to multiple IFN therapies in Pakistan. Further studies are needed to understand multidrug-resistant HCV variants in the Pakistani population.

Hepatic Pharmacokinetics and Pharmacodynamics With Ombitasvir/Paritaprevir/Ritonavir Plus Dasabuvir Treatment and Variable Ribavirin Dosage

Background

It is unknown whether ribavirin (RBV) coadministration modifies the early rate of decline of hepatitis C virus (HCV) RNA in the liver versus plasma compartments, specifically.

Methods

This partially randomized, open-label, phase 2 study enrolled treatment-naive, noncirrhotic patients with HCV genotype 1a. Patients were randomized 1:1 into Arms A and B, and then enrolled in Arm C. Patients received ombitasvir/paritaprevir/ritonavir plus dasabuvir for 12 weeks with either: no RBV for the first 2 weeks followed by weight-based dosing thereafter (Arm A), weight-based RBV for all 12 weeks (Arm B), or low-dose RBV (600 mg) once daily for all 12 weeks. Fine needle aspiration (FNA) was used to determine HCV RNA decline within liver.

Results

Baseline HCV RNA was higher and declined more rapidly in plasma than liver; however, RBV dosing did not impact either median plasma or liver HCV RNA decline during the first 2 weeks of treatment. Liver-to-plasma drug concentrations were variable over time. The most common adverse event was pain associated with FNA.

Conclusions

Coadministration of RBV had minimal visible impact on the plasma or liver kinetics of HCV RNA decline during the first 2 weeks of treatment, regardless of RBV dosing.

Developing therapies to treat hepatitis C infection in post-liver transplant recipients

INTRODUCTION

Currently, hepatitis C virus (HCV) infection remains the most common indication for liver transplant in the United States (US) with almost universal HCV recurrence in the post-liver transplant setting. Previous interferon (IFN)-related efficacy and tolerability concerns about worsening liver function have limited treatment options for many patients with HCV-associated decompensated liver disease and post-liver transplant recipients. However, the last decade has seen a seen a radical shift in the management of HCV with multiple direct-acting antiviral (DAA) treatments that provide more effective, all-oral, IFN-free alternatives. Areas covered: This review will serve to highlight the various pharmacotherapies available to clinicians for patients with HCV recurrence post-liver transplant. A brief history of prior regimens is provided with evidence for newer treatments presented. Also detailed are updated guidelines from societal organizations. Finally, timing of HCV treatment is discussed as the decision to treat patients in a pre or post-liver transplant setting remains challenging. Expert opinion: While there are many potential available therapies for HCV recurrence in the post-liver transplant setting, daclatasvir/sofosbuvir and ledipasvir/sofosbuvir have been the most extensively studied. Newer, pangenotypic generation drugs require more evidence before routine utilization in post-liver transplant recipients.

Ribavirin revisited in the era of direct-acting antiviral therapy for hepatitis C virus infection

Over the past two decades, ribavirin has been an integral component of treatment for hepatitis C virus (HCV) infection, where it has been shown to improve the efficacy of (pegylated) interferon. However, because of treatment-limiting side effects and its additive toxicity with interferon, the search for interferon- and ribavirin-free regimens has been underway. The recent approvals of all-oral direct acting antivirals (DAAs) have revolutionized the HCV therapeutic landscape, and initially it was expected that the role of ribavirin with DAA regimens would be eliminated. On the contrary, what we have witnessed is that ribavirin retains an important role in the optimal treatment of some subgroups of patients, particularly those that historically have been considered the most difficult to cure. Fortunately, it has also been recognized that the safety profile of ribavirin is improved when co-administered with all-oral DAA combinations in the absence of interferon. Despite the antiviral mechanism of action of ribavirin being poorly understood, we now have a range of novel insights into the potential role of ribavirin in all-oral DAA HCV treatment and greater insight into the antiviral mechanism by which it continues to provide clinical benefit for defined patient groups.

Safety and efficacy of sofosbuvir plus ledipasvir with and without ribavirin for chronic HCV genotype-1 infection: a systematic review and meta-analysis

BACKGROUND

Ledipasvir and sofosbuvir are new direct-acting antiviral agents for patients with HCV infection. Ledipasvir inhibits the HCV non-structural 5A protein, while sofosbuvir is a nucleotide polymerase inhibitor. Many studies have evaluated the safety and efficacy of ledipasvir and sofosbuvir combination with and without ribavirin for patients with chronic HCV genotype-1.

METHODS

A computer literature search of PubMed, SCOPUS, Web of Knowledge and Cochrane CENTRAL has been conducted. Studies were screened for eligibility and data were extracted. Sustained virological response (SVR) rate and commonly reported adverse events were pooled as risk ratio (RR) using Review Manager version 5.3 for windows and OpenMeta (Analyst) software.

RESULTS

Eight randomized controlled trials (n=1,892) were pooled in the final analysis. A 12-week ledipasvir and sofosbuvir regimen achieved SVR in 97.5% and 89% of non-cirrhotic and cirrhotic patients, respectively. A 24-week ledipasvir and sofosbuvir regimen achieved SVR in 99.6% and 92.6% in non-cirrhotic and cirrhotic patients, respectively. When ribavirin was added to the treatment regiment, the SVR did not differ significantly in either of the treatment regimens (12-week SVR: 93.9% versus 96.7%, RR=0.97, P=0.19 and 24-week SVR: 94.8% versus 97.2%, RR=0.98, P=0.24).

CONCLUSIONS

The combination of sofosbuvir and ledipasvir achieved high SVR rates (>90%) in both cirrhotic and non-cirrhotic patients with HCV genotype-1. The addition of ribavirin to this regimen did not significantly increase the SVR rates.

Randomized Trial Evaluating the Impact of Ribavirin Mono-Therapy and Double Dosing on Viral Kinetics, Ribavirin Pharmacokinetics and Anemia in Hepatitis C Virus Genotype 1 Infection

In this pilot study (RibaC), 58 hepatitis C virus (HCV) genotype 1 infected treatment-naïve patients were randomized to (i) 2 weeks ribavirin double dosing concomitant with pegylated interferon-α (pegIFN-α), (ii) 4 weeks ribavirin mono-therapy prior to adding pegIFN-α, or (iii) standard-of-care (SOC) ribavirin dosing concurrent with pegIFN-α. Four weeks of ribavirin mono-therapy resulted in a mean 0.46 log₁₀ IU/mL HCV RNA reduction differentially regulated across IL28B genotypes (0.89 vs. 0.21 log₁₀ IU/mL for CC and CT/TT respectively; P = 0.006), increased likelihood of undetectable HCV RNA week 4 after initiating pegIFN-α and thus shortened treatment duration (P<0.05), and decreased median IP-10 concentration from 550 to 345 pg/mL (P<0.001). Both experimental strategies impacted on ribavirin concentrations, and high levels were achieved after one week of double dosing. However, by day 14, double dosing entailed a greater hemoglobin decline as compared to SOC (2.2 vs. 1.4 g/dL; P = 0.03). Conclusion: Ribavirin down-regulates IP-10, and may have an anti-viral effect differently regulated across IL28B genotypes.

Disconnected by design: analytic approach in treatment networks having no common comparator

In a network meta-analysis, comparators of interest are ideally connected either directly or via one or more common comparators. However, in some therapeutic areas, the evidence base can produce networks that are disconnected, in which there is neither direct evidence nor an indirect route for comparing certain treatments within the network. Disconnected networks may occur when there is no accepted standard of care, when there has been a major paradigm shift in treatment, when use of a standard of care or placebo is debated, when a product receives orphan drug designation, or when there is a large number of available treatments and many accepted standards of care. These networks pose a challenge to decision makers and clinicians who want to estimate the relative efficacy and safety of newly available agents against alternatives. A currently recommended approach is to insert a distribution for the unknown treatment effect(s) into a network meta-analysis model of treatment effect. In this paper, we describe this approach along with two alternative Bayesian models that can accommodate disconnected networks. Additionally, we present a theoretical framework to guide the choice between modeling approaches. This paper presents researchers with the tools and framework for selecting appropriate models for indirect comparison of treatment efficacies when challenged with a disconnected framework. Copyright © 2016 John Wiley & Sons, Ltd.

Ribavirin restores IFNα responsiveness in HCV-infected livers by epigenetic remodelling at interferon stimulated genes

OBJECTIVES

Caveats in the understanding of ribavirin (RBV) mechanisms of action has somehow prevented the development of better analogues able to further improve its therapeutic contribution in interferon (IFN)-based and direct antiviral agent-based regimens for chronic HCV or other indications. Here, we describe a new mechanism by which RBV modulates IFN-stimulated genes (ISGs) and contributes to restore hepatic immune responsiveness.

DESIGN

RBV effect on ISG expression was monitored in vitro and in vivo, that is, in non-transformed hepatocytes and in the liver of RBV mono-treated patients, respectively. Modulation of histone modifications and recruitment of histone-modifying enzymes at target promoters was analysed by chromatin immunoprecipitation in RBV-treated primary human hepatocytes and in patients' liver biopsies.

RESULTS

RBV decreases the mRNA levels of several abnormally preactivated ISGs in patients with HCV, who are non-responders to IFN therapy. RBV increases G9a histone methyltransferase recruitment and histone-H3 lysine-9 dimethylation/trimethylation at selected ISG promoters in vitro and in vivo. G9a pharmacological blockade abolishes RBV-induced ISG downregulation and severely impairs RBV ability to potentiate IFN antiviral action and induction of ISGs following HCV infection of primary human hepatocytes.

CONCLUSIONS

RBV-induced epigenetic changes, leading to decreased ISG expression, restore an IFN-responsive hepatic environment in patients with HCV, which may also prove useful in IFN-free regimens.

Distribution of Hepatitis C Virus Genotypes in Bahrain

BACKGROUND

Approximately 170 million people are infected with Hepatitis C virus (HCV) worldwide, making it one of the world's major infectious diseases. There are no published population based studies about the prevalence of HCV genotypes in Bahrain.

OBJECTIVES

Therefore, the aim of the present study was to investigate the prevalence and distribution of HCV genotypes and subtypes among a large sample of patients with chronic HCV infection in Bahrain.

PATIENTS AND METHODS

Serum samples were collected from 202 HCV positive patients; of them 128 had a viral load (> 500 IU/mL) suitable for the type-specific genotyping assay. Gender-wise and age-wise differences in the distribution of HCV genotypes were determined by Chi Square and Fisher's Exact tests.

RESULTS

The predominant genotype among Bahraini patients was type 1 (36.71%), followed by genotypes 3 and 4 (15.6% each) and the lowest frequency was found for genotype 2 (3.9%). Among genotype 1, subtype 1b had the highest frequency (21.09%), followed by subtype 1a (14.06%). Among genotype 3, subtype 3a had the highest frequency (11.72%), while among genotype 4, most of subtypes were undetermined. The frequency of all different HCV genotypes was higher in male patients compared to female patients. Genotype 1 was most common in the age group of 51 - 60 years (38.3%), genotype 2 in 21 - 30 years (60%) and genotype 3 in 51 - 60 years (30%), while genotype 4 was most frequent among the age group > 61 (40%).

CONCLUSIONS

The most common HCV genotype in Bahrain was subtype 1b followed by 1a and 3a. Further studies involving sources of transmission in Bahrain are required to enhance control measures for HCV infection.

Low dose ribavirin has been effective in the treatment of incapacitating muco-cutaneous extrahepatic manifestations in patients with hepatitis C with contraindication or no access for approved antiviral treatment

BACKGROUND AND STUDY AIMS

Chronic hepatitis C virus (HCV) is a major public health problem and represents a common cause of chronic liver disease worldwide. The Egyptian Demographic Health Survey (EDHS) has estimated HCV prevalence in Egypt to be 14.7%. HCV can affect multiple organ systems and cause a variety of extrahepatic manifestations. Most of extrahepatic manifestations affect the skin and mucous membranes; such as lichen planus (LP), psoriasis, and leucocytoclastic vasculitis. The treatment of extrahepatic manifestations has been disappointing in patients not indicated for interferon with no access for the new costly all oral treatments.

PATIENTS AND METHODS

In 2014, thirty Egyptian patients with incapacitating mucocutaneous extrahepatic manifestations due to chronic HCV infection, not indicated for interferon, have been randomised into two groups; group I treated with ribavirin (5-10mg/kg daily divided into 2 doses), and group II treated with local steroids for 3months. Patients were followed up for 3months. Dermatology life quality index score has been measured before and after treatment for all patients.

RESULTS

A significant improvement of mucocutaneous lesions has been accomplished in group I in comparison to group II (p<0.01). All lesions in group I showed a significant improvement except psoriasis (p>0.05). A significant improvement of dermatology life quality index score has been found in patients in group I when compared to group II (p<0.05).

CONCLUSION

We conclude that low dose ribavirin was effective in the treatment of incapacitating mucocutaneous extrahepatic manifestations of chronic HCV infection in patients with contraindication or no access to the approved antiviral treatments.

Current and emerging strategies for the diagnosis, prevention and treatment of Lassa fever

ABSTRACT 

Lassa fever (LF) is a potentially fatal disease that affects an estimated 300,000–500,000 people in endemic areas of west Africa each year. Though past studies have identified fatality rates of 5–20% in patients suspected to have contracted Lassa virus (LASV), new studies using more precise clinical diagnoses and modern diagnostic assays show fatalities rates above 60% in acutely ill patients from endemic regions. Currently, there are no approved vaccines or therapeutics, and only one Comformité Européenne (CE) marked rapid immunodiagnostic for acute LASV infection. Therefore, preventing LASV transmission is the primary goal in endemic regions. Development of rapid immunodiagnostics and research into the efficacy of current treatment options continues toward saving lives in west Africa as well as creating a line of defense against the nefarious use of LASV in bioterrorism settings.

Deep sequencing analysis of viral infection and evolution allows rapid and detailed characterization of viral mutant spectrum

Motivation: The study of RNA virus populations is a challenging task. Each population of RNA virus is composed of a collection of different, yet related genomes often referred to as mutant spectra or quasispecies. Virologists using deep sequencing technologies face major obstacles when studying virus population dynamics, both experimentally and in natural settings due to the relatively high error rates of these technologies and the lack of high performance pipelines. In order to overcome these hurdles we developed a computational pipeline, termed ViVan (Viral Variance Analysis). ViVan is a complete pipeline facilitating the identification, characterization and comparison of sequence variance in deep sequenced virus populations.

Results: Applying ViVan on deep sequenced data obtained from samples that were previously characterized by more classical approaches, we uncovered novel and potentially crucial aspects of virus populations. With our experimental work, we illustrate how ViVan can be used for studies ranging from the more practical, detection of resistant mutations and effects of antiviral treatments, to the more theoretical temporal characterization of the population in evolutionary studies.

Availability and implementation: Freely available on the web at http://www.vivanbioinfo.org

Contact: nshomron@post.tau.ac.il

Supplementary information:Supplementary data are available at Bioinformatics online.

Advances in and the future of treatments for hepatitis C

Enormous progress has been made in the understanding of the hepatitis C virus and the development of novel therapeutic agents since the identification of the virus 25 years ago. From initial interferon monotherapy providing only 6% viral clearance rate in the 1980s, pharmacotherapeutics has now entered an exciting new era with direct-acting antiviral agents demonstrating viral clearance rates of more than 70%. We are now at the beginning of an era where combinations of direct-acting antiviral agents may pave the way for interferon-free regimens, even improving the viral clearance rate to near 100%.

Prevalence of hepatitis C virus genotypes in district bannu, khyber pakhtunkhwa, pakistan

Determination of an individual's hepatitis C virus (HCV) genotypes prior to antiviral therapy has become increasingly important for the clinical management and prognosis of HCV infection. Therefore, this study was conducted to investigate the prevalence of HCV genotypes in HCV infected patients of district Bannu in Khyber Pakhtunkhwa region of Pakistan. Serum samples of 117 seropositive patients were screened for HCV-RNA by using reverse transcriptase-nested polymerase chain reaction (RT-nested PCR) and then PCR positive samples were subjected to HCV genotyping. Out of 117 seropositive samples, 110 samples were found positive by PCR analysis. Genotype 3a was the most prevalent one detected in 38% of patients, followed by genotype 3b in 21% of patients, and then genotype 2a in 12% of patients. However 21% of HCV-PCR positive samples could not be genotyped by method used in this study. Genotype 3a was the most prevalent genotype in patients of all age groups and its prevalence was found high among patients with increasing age (>34 years). Moreover, genotypes 3a and 3b were found to be the most prevalent genotypes in patients with history of shaving by barbers, receiving multiple injections, and dental procedures. In conclusion there is need of further investigation of genotypes of HCV by using more sensitive assays and considering large sample size in district Bannu.

Efficacy and tolerability of combination therapy with interferon-alfa plus ribavirin in patients with chronic hepatitis C virus infection: a single-center study in relapsers and nonresponders to previous treatment with high-dose interferon-alfa monotherapy

BACKGROUND

In chronic hepatitis C virus (HCV) infection, interferon (IFN) monotherapy usually is carried out at doses of 3 to 6 million units (MU) 3 times per week, but treatment efficacy is low.

OBJECTIVE

The aim of our study was to assess the efficacy and tolerability of IFN-alfa2b in combination with ribavirin in relapsers and nonresponders to high-dose IFN treatment (5 to 6 MU 3 times per week). We measured the biochemical and virologic responses to treatment and the risk for relapse during the 24 weeks following the end of treatment.

METHODS

Patients with chronic HCV infection (relapsers and nonresponders to a previous treatment with high-dose IFN) received IFN-alfa2b, 3 MU 3 times per week, and ribavirin, 1000 or 1200 mg/d for 24 or 48 weeks. The patients were then followed up for an additional 24 weeks. Sustained response was defined as normal serum alanine aminotransferase (ALT) level and undetectable HCV RNA 24 weeks after treatment was stopped.

RESULTS

Forty-three patients (32 men, 11 women; mean [SD] age, 45 [2] years; 10 relapsers, 33 nonresponders) were included in the study. Four patients were withdrawn from the study at week 4 of treatment because of treatment-related adverse events, and 1 dropped out. At the end of the treatment period, normalization of serum ALT levels and undetectable HCV RNA levels were seen in 58.1% and 30.2% of patients, respectively. No significant difference in virologic response at the end of treatment was found between nonresponders (10/33 [30.3%]) to previous IFN therapy and relapsers (3/10 [30.0%]). At the end of follow-up, 3 (7.0%) treated patients had sustained response (2 nonresponders to the first IFN course and 1 relapser). All of the patients with sustained response were treated for 24 weeks.

CONCLUSION

Based on the results of our study, combination therapy with IFN-alfa and ribavirin may be of value in a limited number of patients with chronic HCV infection who do not respond to, or relapse after, a first course of treatment with high-dose IFN monotherapy.

What is the future of ribavirin therapy for hepatitis C?

With the introduction of direct-acting antiviral (DAA) therapy against hepatitis C virus (HCV) infection, the field is rapidly evolving towards interferon-free regimens with high sustained virologic response (SVR) rates. The ultimate goal of therapy in chronic HCV infection should include an easily dosed all-oral regimen that is highly effective, inexpensive, pan-genotypic, safe and tolerable, with minimal to no resistance. Various investigational DAA regimens are currently under evaluation with and without ribavirin (Rbv). With the projected arrival of improved therapies over the next 5years, the future role of Rbv comes into question. Despite being plagued by the lack of understanding of its mechanism of action and significant side effects such as anemia, Rbv has been a part of the standard-of-care therapies in chronic HCV infection for more than 10years. As we look towards the future HCV therapy, Rbv may still have utility in the care of patients infected with HCV because of its low cost and potentially added value in combination with other DAAs. This article forms part of a symposium in Antiviral Research on "Hepatitis C: next steps toward global eradication."

Peginterferon-α2a(40 kDa)/ribavirin combination for the treatment of chronic hepatitis C infection

Chronic hepatitis C is the leading cause of liver disease and liver-related mortality in the western world. Treatment of this chronic viral infection has considerably improved with the introduction of ribavirin-interferon combination therapy. Ribavirin (Copegus, Rebetol) is a synthetic nucleoside analogue with broad antiviral effects. It is absorbed readily upon oral administration with meals. Daily doses of up to 1200 mg are usually well-tolerated, causing dose-dependent haemolysis, reversible with dose reduction in most patients, in particular in those with renal insufficiency. In the circulation it is bound to erythrocytes, and eliminated by phosphorylation and deribolysation. The drug accumulates in blood with renal insufficiency. Impairment of hepatic function does not influence drug levels in the circulation. In animal studies, teratogenic and reproductive toxicity was shown. In chronic hepatitis C virus infection, monotherapy with ribavirin has no effect on concentrations of viral RNA or liver histology. Combination therapy with pegylated interferon-alpha2a (40 kDa) (Pegasys) produces significantly higher sustained virological response rates in infections with all viral genotypes, even in advanced stages of liver disease compared pegylated interferon-alpha2a monotherapy, adverse effects and quality of life are not significantly different.

Peginterferon-α2b and ribavirin

Hepatitis C virus infection is among the leading causes of chronic liver disease in the USA and has a worldwide prevalence of approximately 300 million people. Chronic hepatitis C virus is the most common indication for liver transplantation in the USA. Due to the chronic nature of hepatitis C virus infection, these numbers are expected to grow fourfold in the next decade. Interferon-alpha(2b) monotherapy followed by combination therapy with ribavirin have been used to treat chronic hepatitis C virus with limited success. The development of pegylated interferon-alpha(2b), (Peg-intron, Schering-Plough) instituted the next chapter in hepatitis C virus therapy. The demonstration of its safety and efficacy led to a major trial studying coadministration with ribavirin for compensated chronic hepatitis C virus infection. Pegylated interferon combination therapy has improved efficacy over standard interferon combination therapy without an increase in adverse effects. This article reviews the data regarding pegylated interferon-alpha(2b) with ribavirin therapy. The pharmacokinetics and pharmacodynamics of combination therapy will be presented along with clinical trial data. The efficacy and ease of usage of Pegintron and ribavirin support its use for chronic hepatitis C virus infection.

Review article: management of chronic hepatitis C in patients with contraindications to anti-viral therapy

BACKGROUND

There are patients with chronic hepatitis C who are not eligible for the current interferon-based therapies or refuse to be treated due to secondary effects.

AIM

To provide information on alternative treatments for the management of these patients.

METHODS

A PubMed search was performed to identify relevant literature. Search terms included hepatitis C virus, anti-inflammatory treatment, antioxidant, natural products and alternative treatment, alone or in combination. Additional publications were identified using the references cited by primary and review articles.

RESULTS

Several approaches, such as iron depletion (phlebotomy), treatment with ursodeoxycholic acid or glycyrrhizin, have anti-inflammatory and/or anti-fibrotic effects. Life interventions like weight loss, exercise and coffee consumption are associated with a biochemical improvement. Other alternatives (ribavirin monotherapy, amantadine, silibinin, vitamin supplementation, etc.) do not have any beneficial effect or need to be tested in larger clinical studies.

CONCLUSION

There are therapeutic strategies and lifestyle interventions that can be used to improve liver damage in patients with chronic hepatitis C who cannot receive or refuse interferon-based treatments.

Determination of hepatitis C virus genotypes circulating in different districts of Punjab (Pakistan)

INTRODUCTION

Hepatitis C virus (HCV) is a principal cause of severe liver diseases worldwide and a possible source of significant morbidity and fatality in the long term. Information on the genotype is more significant because it has prognostic value in the response to antiviral therapy.

OBJECTIVES

This study aimed to determine the frequency of various HCV genotypes circulating in the different districts of Punjab and to show the pattern distribution of HCV genotypes in different age groups and sexes.

MATERIALS AND METHODS

A total of 542 HCV-positive patients were selected from various districts of the province and were subjected to an HCV genotype-specific assay. Among 542 positive patients, 300 (55.35%) were men and 242 (44.65%) were women. There were 245 (45.20%), 61 (11.25%), 56 (10.33%), 56 (10.33%), 53 (9.77%), 27 (5%), 20 (3.69%), 16 (3%), and eight (1.47%) HCV-positive patients from Lahore, Sargodha, Multan, Toba Tek Singh, Faisalabad, Rawalpindi, Mandi Bahauddin Gujranwala, and Sahiwal districts, respectively.

RESULTS

Of a total of 542 serum samples analyzed, 476 (88%) were successfully genotyped whereas 66 (12%) samples were undetermined genotypes. Among the typable genotypes, 1a was found in 37 (7%), 1b in 18 (3%), 3a in 386 (71%), and genotype 3b in five (1%) patients. Thirty patients (6%) were identified to be infected with mixed HCV genotypes. Genotypes 3a (P=0.0001), 1a (P=0.001), and untypable genotypes (P=0.03) were circulating significantly in all the studied districts. All the genotypes were distributed evenly in male and female patients. The most affected age range of patients was 21-40 years as compared with teenage and older age groups.

CONCLUSION

The study found a significantly high prevalence of HCV among the patients of Punjab. In addition, genotype 1a was found to be a significantly and rapidly increasing genotype in the study area. It appears that HCV-3a (the most prevalent genotype) may be replaced by genotype 1a. If this occurs, it will make the present scenario more complex in terms of response to therapy and economic burden on the health sector of Pakistan. HCV infection is more common in the age group of 21-40 years. All the genotypes were distributed at the same frequency in men and women.

Ribavirin-resistant mutants of human enterovirus 71 express a high replication fidelity phenotype during growth in cell culture

It has been shown in animal models that ribavirin-resistant poliovirus with a G64S mutation in its 3D polymerase has high replication fidelity coupled with attenuated virulence. Here, we describe the effects of mutagenesis in the human enterovirus 71 (HEV71) 3D polymerase on ribavirin resistance and replication fidelity. Seven substitutions were introduced at amino acid position 3D-G64 of a HEV71 full-length infectious cDNA clone (26M). Viable clone-derived virus populations were rescued from the G64N, G64R, and G64T mutant cDNA clones. The clone-derived G64R and G64T mutant virus populations were resistant to growth inhibition in the presence of 1,600 μM ribavirin, whereas the growth of parental 26M and the G64N mutant viruses were inhibited in the presence of 800 μM ribavirin. Nucleotide sequencing of the 2C and 3D coding regions revealed that the rate of random mutagenesis after 13 passages in the presence of 400 μM ribavirin was nearly 10 times higher in the 26M genome than in the mutant G64R virus genome. Furthermore, random mutations acquired in the 2C coding regions of 26M and G64N conferred resistance to growth inhibition in the presence of 0.5 mM guanidine, whereas the G64R and G64T mutant virus populations remained susceptible to growth inhibition by 0.5 mM guanidine. Interestingly, a S264L mutation identified in the 3D coding region of 26M after ribavirin selection was also associated with both ribavirin-resistant and high replication fidelity phenotypes. These findings are consistent with the hypothesis that the 3D-G64R, 3D-G64T, and 3D-S264L mutations confer resistance upon HEV71 to the antiviral mutagen ribavirin, coupled with a high replication fidelity phenotype during growth in cell culture.

ITPA gene polymorphisms significantly affect hemoglobin decline and treatment outcomes in patients coinfected with HIV and HCV

Published studies have described a strong association with a single-nucleotide polymorphism (SNP) in the inosine triphosphate pyrophosphatase (ITPA) gene and ribavirin (RBV)-induced hemolytic anemia in HCV-infected patients receiving pegylated interferon (pegIFN) and RBV. This study sought to evaluate the effect of these polymorphisms on anemia, hemoglobin reduction, HCV kinetics, and treatment outcomes. Sixty-three patients coinfected with HIV and HCV and 58 patients infected with HCV only were treated with pegIFN/RBV were genotyped using the ABI TaqMan allelic discrimination kit for the 2 ITPA SNP variants rs1127354 and rs7270101. A composite variable of ITPA deficiency using both SNPs was created as previously reported. Statistical analysis was performed using Mann-Whitney test or Chi square/Fishers exact test for categorical data and mixed model analysis for multiple variables. Thirty-five patients (30%) were predicted to have reduced ITPA activity. ITPA deficiency was found to be protective against the development of hemoglobin reduction >3 g/dl over the course of treatment. The rates of hemoglobin reduction >3 g/dl decreased in correlation with the severity of ITPA deficiency. ITPA deficiency was associated with slower hemoglobin decline early in treatment (week 4, P = 0.020) and rapid virologic response (RVR) at week 4 (P = 0.017) in patients coinfected with HIV and HCV. ITPA polymorphisms are associated with hemoglobin decline and in patients coinfected with HIV and HCV it is also associated with early virologic outcomes. Determination of ITPA polymorphisms may allow prediction of RBV-induced anemia and earlier initiation of supportive care to ensure optimal therapeutic outcomes.

Ribavirin exerts differential effects on functions of Cd4+ Th1, Th2, and regulatory T cell clones in hepatitis C

Ribavirin improves outcomes of therapy in chronic hepatitis C but its mode of action has still remained unclear. Since ribavirin has been proposed to modulate the host’s T cell responses, we studied its direct effects on CD4⁺ T cell clones with diverse functional polarization which had been generated from patients with chronic hepatitis C. We analysed in vitro proliferation ([³H] thymidine uptake) and cytokine responses (IL-10, IFN-gamma) at varying concentrations of ribavirin (0–10µg/ml) in 8, 9 and 7 CD4⁺ TH1, TH2 and regulatory T cell (Treg) clones, respectively. In co-culture experiments, we further determined effects of ribarivin on inhibition of TH1 and TH2 effector cells by Treg clones. All clones had been generated from peripheral blood of patients with chronic hepatitis C in the presence of HCV core protein. Ribavirin enhanced proliferation of T effector cells and increased production of IFN-gamma in TH1 clones, but had only little effect on IL-10 secretion in TH2 clones. However, ribavirin markedly inhibited IL-10 release in Treg clones in a dose dependent fashion. These Treg clones suppressed proliferation of T effector clones by their IL-10 secretion, and in co-culture assays ribavirin reversed Treg-mediated suppression of T effector cells. Our in vitro data suggest that - in addition to its immunostimulatory effects on TH1 cells - ribavirin can inhibit functions of HCV-specific Tregs and thus reverses Treg-mediated suppression of T effector cells in chronic hepatitis C.

Effect of mosapride citrate on gastric emptying in interferon-induced gastroparesis

BACKGROUND AND OBJECTIVES

Gastroparesis, a gastrointestinal autonomic neuropathy, is a common adverse reaction in chronic hepatitis C (CHC) patients receiving interferon therapy. Current therapeutic options are limited. We evaluated the efficacy of mosapride for IFN-induced gastroparesis.

METHODS

Twenty-four consecutive CHC patients were randomly assigned to either the control group, which received pegylated interferon α-2b at 1.5 μg/kg/week and ribavirin at 600-1,000 mg/day, depending on body weight (PegIFN/RBV), or the mosapride group, which received PegIFN/RBV plus mosapride at 15 mg/person/day. The solid-phase gastric emptying half-times (T1/2) of the total, proximal, and distal stomach (scintigraphy) and digestive symptoms (questionnaire) were measured within one week before and four weeks after initiation of the assigned therapy. The test meal comprised a 200-g pancake containing Tc-99m diethylenetriamine pentaacetic acid.

RESULTS

In the control group, after PegIFN/RBV initiation, a significant increase was observed in the total T1/2 (before: 84.0 ± 22.1 min versus after: 100.8 ± 28.9 min, P = 0.03), the distal T1/2 (before: 95.3 ± 32.2 min versus after: 115.3 ± 41.4 min, P = 0.03), and digestive symptom score (before: 3.2 ± 1.4 versus after: 8.1 ± 4.8, P = 0.02); proximal T1/2 change was not significant. In the mosapride group, no significant delays were observed in the total, proximal, and distal T1/2 values; the change in symptom scores was not significant.

CONCLUSIONS

Mosapride improved total and distal gastric motility in IFN-induced gastroparesis, and consequently relieved symptoms.

Early dynamics of viremia in patients with genotype 1b chronic hepatitis C: Peg-IFNalpha2a shows earlier viral decline than peg-IFNalpha2b in combination therapy with ribavirin

Background

We aimed to assess differences in early viral dynamics following treatment with either peg-IFNα2a or peg-IFNα2b in combination with ribavirin in patients with chronic genotype 1b HCV infection.

Material/Methods

Sixty-one patients in the peg-IFNα2a + ribavirin treatment (group α2a) and 88 patients in the peg-IFNα2b + ribavirin treatment (group α2b) were retrospectively analyzed. The early dynamics of HCV RNA over 12 weeks were evaluated. Sustained virological response (SVR) was defined as undetectable HCV RNA at week 24 after end of therapy. First- (day 0–1) and second-phase (day 1–28) viral decline rates were calculated in accordance with theoretical formulae.

Results

Baseline HCV RNA concentrations were almost similar between the 2 groups. In group α2a, viral decline was significantly greater than in group α2b at weeks 4, 8, and 12. In group α2a, viral decline was significantly greater in SVR patients than in non-SVR patients at week 2, whereas significantly greater viral decline in SVR patients was found during weeks 1–12 in group α2b. The first-phase viral decline rate was significantly larger in group α2a than in group α2b (1.31±0.84 vs. 0.70±0.97 log IU/mL/day; p<0.0001). Within SVR patients, first-phase viral decline rate was significantly larger in group α2a compared with group α2b (1.45±0.85 vs. 0.78±1.0 log IU/mL/day; p<0.0001). Second-phase viral decline rate was comparable between the groups.

Conclusions

Peg-IFNα2a showed earlier viral decline than peg-IFNα2b and the difference was obvious, especially in the first-phase viral decline.