The Hepatitis C virus (HCV) is a blood-transmitted virus responsible for persistent inflammation, presenting a substantial worldwide health challenge. HCV, characterized by a positive-stranded ribonucleic acid genome, possesses an intricate genetic makeup encoding both structural and non-structural proteins, crucial for sustaining its life cycle. The Direct Acting Antivirals have revolutionized the treatment landscape of HCV promoting higher Sustained Virological Response rates. Despite significant advancements in treatment, no vaccines are currently available against HCV. The development of effective HCV vaccines becomes challenging as the genetic diversity of HCV virus and its complex nature of the immune response required for protection. In this work, the immunoinformatics methods were utilized to develop a multiple-epitope-based vaccine towards an effective treatment against the viral HCV polyprotein. The vaccine was constructed by T-cell epitopes extracted from the viral polyprotein of HCV genotypes 1a and 1b. The vaccine was highly antigenic, non-toxic, and non-allergenic. Effective binding of the designed vaccine construct was studied by forming complexes with the human immune Toll-Like Receptors; TLR3 and TLR8. The MD simulation of these receptor-vaccine complexes were performed for 50ns and the immunological simulation of modeled vaccine in presence of receptors for 365 days timeline validated the stability of the constructed vaccine. The in-silico vaccine construct developed from this work might be beneficial as prophylactic measures against the HCV variants, if explored further in in vivo and in vitro methods. Consequently, this research outcome is presumed to have implications in the development of safer and more efficient vaccines for lethal diseases.

The online version contains supplementary material available at 10.1007/s40203-024-00275-4.

Hepatitis B and Hepatitis C are viral causes of Hepatitis that lead to significant worldwide mortality and morbidity through the sequelae of fibrosis and hepatocellular carcinoma. In this review, we have summarized recent studies that have examined the effects of antiviral therapy on the regression of fibrosis and the reduction in mortalities associated with the viruses. Antiviral therapy significantly decreases mortality and induces the regression of fibrosis.

The discovery of the hepatitis C virus (HCV) and direct-acting antiviral (DAA) drugs is one of the major milestones in the last 3 decades of medicine. These discoveries encouraged the World Health Organization (WHO) to set an ambitious goal to eliminate HCV by 2030, meaning "a 90% reduction in new cases of chronic HCV, a 65% reduction in HCV deaths, and treatment of 80% of eligible people with HCV infections."

This review summarizes the key achievements from the discovery of HCV to the development of effective treatment and global elimination strategies. A better understanding of HCV structure, enzymes, and lifecycle led to the introduction of new drug targets and the discovery of DAA. Massive public health interventions are required, such as screening, access to care, treatment, and post-care follow-up, to make the most of DAA's potential. Screening must be supported by fast, accessible, sensitive, specific HCV diagnostic tests and noninvasive methods to determine the stage of liver disease. Linkage to care and treatment access are critical components of a comprehensive HCV elimination program, and decentralization plays a key role in ensuring their effectiveness.

Effective and simple screening strategies, rapid diagnostic tools, linkage to health care, and accessible treatment are key elements to achieving the WHO's goal. Incorporating treatment as prevention strategies into elimination programs together with preventive education and harm reduction interventions can have a profound and lasting impact on reducing both the incidence and prevalence of HCV. However, WHO's goal can be challenging to implement because of the need for high financial resources and strong political commitment.

In meta-analysis literature, there are several checklists describing the procedures necessary to evaluate studies from a qualitative point of view, whereas preliminary quantitative and statistical investigations on the "combinability" of trials have been neglected. Covariate balance is an important prerequisite to conduct meta-analysis. We propose a method to identify unbalanced trials with respect to a set of covariates, in presence of covariate imbalance, namely when the randomized controlled trials generate a meta-sample that cannot satisfy the requisite of randomization/combinability in meta-analysis. The method is able to identify the unbalanced trials, through four stages aimed at achieving combinability. The studies responsible for the imbalance are identified, and then they can be eliminated. The proposed procedure is simple and relies on the combined Anderson-Darling test applied to the Empirical Cumulative Distribution Functions of both experimental and control meta-arms. To illustrate the method in practice, two datasets from well-known meta-analyses in the literature are used.

In the 1970s, an unknown virus was suspected for documented cases of transfusion-associated hepatitis, a phenomenon called non-A, non-B hepatitis. In 1989, the infectious transmissible agent was identified and named hepatitis C virus (HCV) and, soon enough, the first diagnostic HCV antibody test was developed, which led to a dramatic decrease in new infections. Today, HCV infection remains a global health burden and a major cause of liver cirrhosis, hepatocellular carcinoma and liver transplantation. However, tremendous advances have been made over the decades, and HCV became the first curable, chronic viral infection. The introduction of direct antiviral agents revolutionized antiviral treatment, leading to viral eradication in more than 98% of all patients infected with HCV. This Perspective discusses the history of HCV research, which reads like a role model for successful translational research: starting from a clinical observation, specific therapeutic agents were developed, which finally were implemented in national and global elimination programmes.

Human respiratory syncytial virus (hRSV) is a major cause of respiratory illness in young children and can cause severe infections in the elderly or in immunocompromised adults. To date, there is no vaccine to prevent hRSV infections, and disease management is limited to preventive care by palivizumab in infants and supportive care for adults. Intervention with small-molecule antivirals specific for hRSV represents a good alternative, but no such compounds are currently approved. The investigation of existing drugs for new therapeutic purposes (drug repositioning) can be a faster approach to address this issue. In this study, we show that chloroquine and pyrimethamine inhibit the replication of human respiratory syncytial virus A (long strain) and synergistically increase the anti-replicative effect of ribavirin in cellulo. Moreover, chloroquine, but not pyrimethamine, inhibits hRSV replication in the mouse model. Our results show that chloroquine can potentially be an interesting compound for treatment of hRSV infection in monotherapy or in combination with other antivirals.

Exactly 30 years ago, hepatitis C virus was identified. Over the years, tremendous success has been achieved in the treatment of hepatitis C, which is currently considered to be an almost completely curable disease. The review presents the main stages in the development of hepatitis C antiviral therapy, the efficacy of various treatment regimens. The greatest progress in treatment was noted over the past 5 years when drugs with direct antiviral action appeared and began to be widely used, including in Russia, which ensure the elimination of the virus in 90-95% of cases.

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 clearly plays a role in chronic hepatitis C treatment response. The equilibrative nucleoside transporter-1 codified by SLC29A1 gene has been associated with ribavirin uptake into hepatocytes and erythrocytes. rs760370A>G single nucleotide polymorphism (SNP) at the SLC29A1 gene may have a role in ribavirin-based regimen treatment response. Accuracy of the polymerase-chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay compared with the TaqMan assay for the detection of the SNP rs760370 at the main ribavirin transporter gene and its relation to sustained virological response in chronic hepatitis C virus (HCV) patients treated with pegylated interferon-ribavirin therapy. The study included 100 chronic HCV patients who were treated with pegylated interferon-ribavirin therapy. The patients were categorized according to the treatment response into responders (50 patients) and null responders (50 patients). rs760370 SNP was measured using TaqMan 5-nuclease assay and by the newly developed PCR-based RFLP assay. The overall accuracy of the newly developed PCR-RFLP assay compared with the TaqMan assay for rs760370 polymorphism detection was 100%. Allelic frequencies at rs760370 were as follows: A/A genotype (28%), A/G genotype (58%), and G/G genotype (14%). Treatment response was not significantly related with rs760370 polymorphism (P = 0.5). Ribavirin-induced anemia was good predictor of sustained virological response (P = 0.001), but was not related to rs760370 polymorphism (P = 0.92). PCR-RFLP assay is an accurate, cost-effective method in the detection of rs760370 compared with TaqMan assay. rs760370 SNP cannot serve as predictor of response in chronic HCV patients treated with interferon ribavirin therapy.

The aim of this study was to determine risk factors for premature treatment discontinuation among patients with hepatitis C and advanced fibrosis with advanced fibrosis treated with interferon (IFN)-free direct antiviral agents (DAA)-based therapy.

We included all patients with chronic hepatitis C virus infection and advanced liver fibrosis in whom treatment was initiated with IFN-free DAA therapy at a university hospital from December 2015 through June 2016. We prospectively collected data from medical records using standardized questionnaires and evaluated them using Epi Info 7.1.2.0. The primary outcome was treatment interruption and associated factors.

In total, 214 patients were included in this study; 180 patients were treated with sofosbuvir (SOF)+daclatasvir±ribavirin (RBV), 31 received SOF+simeprevir±RBV, and three were treated with SOF+RBV. Treatment discontinuation rate was 8.9% (19 patients) and cirrhotic decompensation was the main reason [8 (42.1%)]. Among patients with Child B or C cirrhosis (31), 10 (32.2%) prematurely interrupted treatment. The risk factors for treatment discontinuation in univariate analysis were older age (P=0.0252), higher comorbidity index (P=0.0078), higher model for end-stage liver disease (P<0.0001), higher fibrosis index based on the 4 factores (P=0.0122), and lower hemoglobin (P=0.0185) at baseline. Multivariate analysis showed that older age (odds ratio: 1.1, 95% confidence interval: 1.02-1.19) and higher model for end-stage liver disease (odds ratio: 1.27, 95% confidence interval: 1.03-1.56) were associated with premature treatment interruption.

Older age and advanced liver disease were related to treatment interruption. Identification of risk factors associated with treatment discontinuation is important to recognize patients who should be followed up closely during treatment, ando those whom possibly may not benefit from immediate DAA treatment or should be followed up closely during treatment.

Canine distemper virus (CDV) is a major infectious disease of dogs. Although vaccines were successful to control CDV spread in canine population, the disease is still common and may pose a threat to unvaccinated dogs. In the attempt to develop specific anti-viral therapeutic tools, the efficacy of several molecules against CDV has been investigated in vitro. In this study the antiviral efficacy in vitro against CDV of ribavirin and boceprevir alone or in combination was evaluated. CDV growth in VERO cells was inhibited by ribavirin, by boceprevir and by a combination of the two molecules at non-cytotoxic concentrations, as evaluated by end-point viral titration in cell monolayers and by quantification of viral RNA using quantitative RT-PCR. By end-point titration, a statistically significant reduction in CDV replication was observed only using ribavirin and boceprevir in combination. By quantitative RT-PCR, a significant reduction of viral growth was observed either in cells treated with ribavirin or boceprevir or with both the two molecules. The association of ribavirin or boceprevir was able to decrease CDV growth by up to 3.4458 logs with respect to untreated infected cells, chiefly at the highest virus dilutions. The results obtained in this study may constitute an important basis for the development of CDV therapies.

The accumulation of metabolic by-products remains a critical challenge in the development of mammalian cells culture processes as it impacts cellular growth, productivity and product quality. Although the overexpression of the PYC2 gene was shown to significantly improve the nutrient metabolism efficiency of mammalian cells, its impact on recombinant protein quality has not been investigated yet. In this study, we assess the effect of this metabolic engineering strategy on the quality of a recombinant therapeutic glycoprotein, the human interferon α2b (IFNα2b). As inferred from densitometry analysis of SDS-PAGE gels, PYC2-overexpressing cells sustained a higher percentage of intact glycosylated IFNα2b at the late stage of batch cultures, which was correlated with prolonged viability and reduced accumulation of waste metabolites. Contrarily to the IFNα2b produced by the PYC2 cells, LC-MS analysis confirmed the presence of less glycosylated IFNα2b as well as the occurrence of proteolytic cleavage in the IFNα2b produced in the parental cells. Taken together, these results indicate that PYC2-overexpression in mammalian cells leads to extended favorable conditions for glycosylation and offer an attractive approach to mass-produce high-quality recombinant proteins.

The aim of this study was to determine risk factors for adverse events (AE)-related treatment discontinuation and severe anemia among patients with chronic hepatitis C virus (HCV) genotype 1 infection, treated with first-generation protease inhibitor (PI)-based therapy. We included all patients who initiated treatment with PI-based therapy at a Brazilian university hospital between November 2013 and December 2014. We prospectively collected data from medical records using standardized questionnaires and used Epi Info 6.0 for analysis. Severe anemia was defined as hemoglobin ≤8.5 mg/dL. We included 203 patients: 132 treated with telaprevir (TVR) and 71 treated with boceprevir (BOC). AE-related treatment discontinuation rate was 19.2% and anemia was the main reason (38.5%). Risk factors for treatment discontinuation were higher comorbidity index (OR=1.85, CI=1.05-3.25) for BOC, and higher bilirubin count (OR=1.02, CI=1.01-1.04) and lower BMI (OR=0.98, CI=0.96-0.99) for TVR. Severe anemia occurred in 35 (17.2%) patients. Risk factors for this outcome were lower estimated glomerular filtration rate (eGFR; OR=0.95, CI=0.91-0.98) for patients treated with TVR, and higher comorbidity index (OR=2.21, CI=1.04-4.67) and ribavirin dosage (OR=0.84, CI=0.72-0.99) for those treated with BOC. Fifty-five (57.3%) patients treated with TVR and 15 (27.3%) patients treated with BOC achieved sustained virological response (SVR). Among patients who received TVR and interrupted treatment due to AE (n=19), only 26.3% (n=5) achieved SVR (P=0.003). Higher number of comorbidities, lower eGFR and advanced liver disease are associated with severe anemia and early treatment cessation, which may compromise SVR achievement.

Interferon alpha (IFNα) is one of the most famous drugs for the treatment of chronic hepatitis C and various types of human malignancy. Protein drugs, including IFNα, are generally administered by subcutaneous or intramuscular injection due to their poor permeability and low stability in the bloodstream or gastrointestinal tract. Therefore, in the present study, novel IFNα-coated polyvinyl alcohol-based microneedle arrays (IFNα-MNs) were fabricated for the transdermal delivery of IFNα without the painful injection. IFNα was rapidly released from MNs in phosphate buffered solution and these MNs presented piercing ability in the rat skin. Slight erythema and irritation were observed when MNs were applied to the rat skin, but these skin damages completely disappeared within 24 h after removing the IFNα-MNs. Furthermore, the pharmacokinetic parameters of IFNα-MNs were similar to those of IFNα subcutaneous administration. Finally, IFNα-MNs showed a significant antitumor effect in tumor bearing mice similar to that of IFNα subcutaneous administration. These results indicate that IFNα-MNs are a useful biomaterial tool for protein drug therapy and can improve the quality of life in patients by avoidance of painful injections.

Evidence over the past decades have shown that HIV/HCV coinfected patients did not respond as well to HCV therapy as HCV mono-infected patients. However, these paradigms are being recently reassessed with the improvements of care for HIV and HCV patients. This article reviews these original paradigms and how the new data is impacting upon them. Treatment efficacy now appears comparable for HIV/HCV coinfected and HCV mono-infected patients, while liver fibrosis progression is increasingly similar in optimally managed patients. Additional importance of therapy is directed to drug-drug interactions and the impact of HCV reinfection, as well as the possibility of transmitted drug resistance.

To evaluate systematically the clinical efficacy and safety of potassium dehydroandrographolide succinate injection (PDS) in treatment of infantile pneumonia.

Randomized controlled trials (RCTs) of infantile pneumonia treated by PDS were searched in China National Knowledge Infrastructure Database, China Science and Technology Journal Database, Wanfang Database, Chinese Biomedical Literature Database, PubMed, and Cochrane Library, from January 1979 to July 2013. Two reviewers independently retrieved the RCTs and extracted the information. The quality of included studies was assessed by the Cochrane risk of bias, and a Meta-analysis was conducted with Review Manager 5.2 software.

A total of 9 studies with 1056 participants were included. The quality of the studies was generally no high, only one study mentioned the random method. The Meta-analysis indicated that PDS was significantly superior to the conventional therapy in the total effective rate [relative risk (RR) = 1.21, 95% CI (1.14, 1.27), P < 0.000 01], the time of temperature recovery [mean difference (MD) = -1.43, 95% CI (-1.75, -1.11), P < 0.000 01], rale disappeared and cough relieving [MD = -1.44, 95% CI (-1.93, -0.90), P < 0.000 01]. Six adverse drug reactions from five studies mainly represented rash and diarrhea, and no serious ADRs were reported.

Based on this systematic review, PDS was proved effective and relatively safe in treatment of infantile pneumonia. However the articles enrolled in the study were not high in quality, studies with higher quality should be conducted for assessment of efficacy and safety of PDS in treatment of infantile pneumonia.

The hepatitis C virus (HCV) was discovered in the late 1980s. Interferon (IFN)-α was proposed as an antiviral treatment for chronic hepatitis C at about the same time. Successive improvements in IFN-α-based therapy (dose finding, pegylation, addition of ribavirin) increased the rates of sustained virologic response, i.e. the rates of curing HCV infection. These rates were further improved by adding the first available direct-acting antiviral (DAA) drugs to the combination of pegylated IFN-α and ribavirin. An IFN-free era finally started in 2014, yielding rates of sustained virologic response over 90% in patients treated for 8 to 24 weeks with all-oral regimens. Major challenges however remain in implementation of these new treatment strategies, not only in low- to middle-income countries, but also in high-income countries where the price of these therapies is still prohibitive. Elimination of HCV infection through treatment in certain areas is possible but raises major public health issues.

To systematically evaluate the clinical efficacy and safety of Potassium Dehydroandrographolide Succinate Injection (PDSI) in the treatment of child epidemic parotitis (EP).

Randomized controlled trials (RCTs) regarding PDSI in the treatment of child EP were searched in China National Knowledge Infrastructure, Wanfang Database, Chinese Biomedical Literature Database, PubMed, and Cochrane Library from inception to July 30, 2013. Two reviewers independently retrieved RCTs and extracted information. The Cochrane risk of bias method was used to assess the quality of included studies, and a meta-analysis was conducted with RevMan 5.2 software.

A total of 11 studies with 818 participants were included. The quality of the studies was generally low, among which only one study mentioned the random method. The meta-analysis indicated that PDSI was more effective than the conventional therapy with Western medicine for EP in the outcomes of the total effective rate [relative risk (RR)=1.23, 95% confidence interval (CI) [1.14, 1.33], P<0.01], the time of temperature return to normal, the time of detumescence [mean difference (MD)=-2.10, 95% CI [-2.78,-1.41], P<0.01], and the incidence of complications (RR=0.14, 95% CI [0.03, 0.72], P=0.02). There were 6 adverse drug reactions (ADRs) in this systematic review, 2 of which were mainly represented rash and diarrhea in the experiment group, while another 4 ADRs occurred in the control group.

Based on the systematic review, PDSI was effectiveness and relatively safety in the treatment of child EP. But further rigorously designed trials are warranted to determine its effectiveness.

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.

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.

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.

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.

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.

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."

Pulmonary arterial hypertension (PAH) is a rare disorder characterized by progressive obliteration of the pulmonary microvasculature, resulting in elevated pulmonary vascular resistance and premature death. According to the current classification, PAH can be associated with exposure to certain drugs or toxins, particularly appetite suppressant drugs, such as aminorex, fenfluramine derivatives and benfluorex. These drugs have been confirmed to be risk factors for PAH and were withdrawn from the market. The supposed mechanism is an increase in serotonin levels, which was demonstrated to act as a growth factor for the pulmonary arterial smooth muscle cells. Amphetamines, phentermine and mazindol were less frequently used but are also considered as possible risk factors for PAH. Dasatinib, a dual Src/Abl kinase inhibitor, used in the treatment of chronic myelogenous leukaemia was associated with cases of severe PAH, in part reversible after its withdrawal. Recently several studies raised the potential endothelial dysfunction that could be induced by interferon, and few cases of PAH have been reported with interferon therapy. Other possible risk factors for PAH include: nasal decongestants, like phenylpropanolamine, dietary supplement - L-Tryptophan, selective serotonin reuptake inhibitors, pergolide and other drugs that could act on 5HT2B receptors. Interestingly, PAH remains a rare complication of these drugs, suggesting possible individual susceptibility and further studies are needed to identify patients at risk of drugs induced PAH.

The widely-accepted treatment outcome for chronic hepatitis C is the sustained viral response (that is, no measurable viral RNA in blood six months after treatment). However, this surrogate outcome (as well as the previously employed biochemical and histologic ones) has never been validated. This situation exists because there are very few randomized clinical trials that have used clinical events (mortality or manifestations of decompensated cirrhosis) as outcomes, because those clinical events only occur after many years of infection. Patients in whom initial therapy fails to produce sustained viral responses do become potential candidates for retreatment; some of these individuals are not candidates for ribavirin or protease inhibitors and consideration could be given to retreatment with interferon alone.

To assess the benefits and harms of interferon monotherapy retreatment in chronic hepatitis C patients and to validate the currently employed surrogate outcomes in this group of patients.

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until 16 August 2012.

Randomized trials comparing interferon versus placebo or no treatment in chronic hepatitis C nonresponders and relapsers to previous interferon.

The primary outcomes were mortality (all-cause and hepatic), quality of life, and adverse events. Secondary outcomes were liver-related morbidity, sustained viral responses, biochemical responses, histologic improvements, and costs. We used both fixed-effect and random-effects model meta-analyses, reporting only the former if no difference existed.

Seven trials were identified. Two of them were at low risk of bias (the HALT-C and EPIC3 trials) and included 1676 patients. Both of these trials addressed the role of long-term low-dose pegylated interferon therapy in patients with severe fibrosis (demonstrated on liver biopsy) and were designed to assess the clinical outcomes. The remaining five trials included 300 patients and were at high risk of bias. Based on all trials reporting the outcomes, no significant difference was observed in either all-cause mortality (78/843 (9.3%) versus 62/867 (7.2%); risk ratio (RR) 1.30, 95% confidence interval (CI) 0.95 to 1.79; 3 trials) or hepatic mortality (41/532 (7.7%) versus 40/552 (7.2%); RR 1.07, 95% CI 0.70 to 1.63; 2 trials); however, when only the two trials at low risk of bias were combined, all-cause mortality was significantly higher in the recipients of the pegylated interferon (78/828 (9.4%) versus 57/848 (6.7%); RR 1.41, 95% CI 1.02 to 1.96) although trial sequential analysis could not exclude the possibility of random error. There was less variceal bleeding in the recipients of the interferon (4/843 (0.5%) versus 18/867 (2.1%); RR 0.24, 95% CI 0.09 to 0.67; 3 trials), although again trial sequential analysis could not exclude the presence of a type I error and the effect could not be confirmed in a random-effects model meta-analysis. No significant differences were seen with regard to the development of ascites, encephalopathy, hepatocellular carcinoma, or the need for liver transplantation. One trial reported quality of life data; the pain score was significantly worse in the recipients of the pegylated interferon. Adverse effects tended to be more common in the interferon recipients; the ones that were significantly more common included hematologic complications, infections, flu-like symptoms, and rash. The recipients of interferon had significantly more sustained viral responses (20/557 (3.6%) versus 1/579 (0.2%); RR 15.38, 95% CI 2.93 to 80.71; 4 trials) and a type I error was excluded by trial sequential analysis. The METAVIR activity score also improved (36/55 (65%) versus 20/46 (43.5%); RR 1.49, 95% CI 1.02 to 2.18; 2 trials). No significant differences were seen with regard to histologic fibrosis assessments.

The clinical data were limited to patients with histologic evidence of severe fibrosis who were retreated with pegylated interferon. In this scenario, retreatment with interferon did not appear to provide significant clinical benefit and, when only the trials at low risk of bias were considered, retreatment for several years may even have increased all-cause mortality. Such treatment also produced adverse events. On the other hand, the treatment did result in improvement in some surrogate outcomes, namely sustained viral responses and histologic evidence of inflammation. Interferon monotherapy retreatment cannot be recommended for these patients. No clinical data are available for patients with less severe fibrosis. The sustained viral response cannot be used as a surrogate marker for hepatitis C treatment in this clinical setting with low sustained viral response rates and needs to be validated in others in which higher sustained viral response rates are reported.

Boceprevir was the first agent, along with telaprevir, of a novel class of direct-acting antivirals that entered clinical practice for the treatment of chronic hepatitis C. Boceprevir is an antiprotease that directly blocks hepatitis C virus (HCV) replication. Two studies in patients with HCV genotype 1 infection have shown that addition of boceprevir to the standard of care, ie, pegylated interferon-alfa (PEG-IFN-α) and ribavirin, markedly increased the rate of sustained virological response. A sustained virological response was obtained in about 70% of patients who had never been treated, as well as in 69%-75% and 40% of previous relapsers and nonresponders to PEG-IFN-α-ribavirin, respectively. Side effects were observed in almost all treated patients. Anemia, the most frequent adverse event related to administration of boceprevir, occurred in about 50% of patients. The decision to add boceprevir to the standard of care is made on an individual basis, and takes into account the prognosis of the liver disease, the efficacy of therapy, as it could be at best predicted, and the side effects that may arise, taking into account the comorbidities of the patient. Ultimately, the treatment must be accepted by the patient, who should fully understand the benefits and risks. Boceprevir trials were designed with the concept of individualized and response-guided therapy which establishes treatment decisions on how rapidly patients respond to treatment. Individualized therapy for chronic hepatitis C is based on patient and viral characteristics to make the best choice about whether a person will benefit from therapy and to evaluate on-treatment predictors of response to shorten therapy in patients with a rapid response as well as in patients who did not respond sufficiently to expect HCV eradication. This review focuses on the main results obtained so far, their impact on the treatment of patients with chronic hepatitis C, and potential therapeutic perspectives.

Today, treatment of chronic hepatitis C is based on a synergistic combination of pegylated interferon and ribavirin with antiprotease inhibitors. Haemolytic anaemia, which is the major side effect of ribavirin treatment, disrupts ribavirin treatment compliance and varies significantly from one patient to another. There is an individual susceptibility to ribavirin haemolysis. With a view to studying haemolysis, and thus optimizing the treatment response, we have developed a new in vitro tool for analysing the ribavirin-induced lysis of red blood cells.

Resuspended red blood cells were incubated with isotonic buffer and a range of concentrations of ribavirin. Haemolysis was quantified by spectrophotometric measurement of the supernatant at 540 nm. The assay was used to test the effects of various compounds and to investigate the susceptibility of patients to haemolytic anaemia.

In our assay, the degree of haemolysis is dependent on the ribavirin concentration used and can be inhibited by the addition of dipyridamole (50% inhibitory concentration [IC(50)] 30 μM), ATP or glutathione (IC(50) 1.63 mM and 767 μM, respectively). We observed a strong decrease in red blood cell haemolysis in the presence of the ribavirin prodrug viramidine (Taribavirin(®)). When testing the performance of this assay with blood from 24 patients before treatment, we observed a strong correlation between in vitro haemolysis before treatment and the decrease in haemoglobin levels seen in vivo during subsequent treatment (P<0.001).

With this new tool it is possible to better evaluate individual susceptibility to ribavirin-induced haemolysis before the start of treatment. In addition, this model will enable the mechanism of ribavirin-induced anaemia to be further explored and allow molecules that could reduce ribavirin haemolysis to be screened and tested in vitro. This approach could help optimize current and future therapeutic strategies involving ribavirin in the treatment of chronic hepatitis C.

The manner in which ribavirin (RBV) enhances the antiviral effects of interferon (IFN) against hepatitis C virus (HCV) remains unknown. We investigated whether RBV modifies IFN-stimulated genes (ISGs) in vivo and in vitro.

We measured the messenger RNA (mRNA) levels of ISGs in T lymphocytes from patients with HCV infection who were receiving IFN-α therapy with or without RBV. We added RBV and/or IFN-α to a plasmid-based HCV replication system containing a full-length HCV genotype 1a sequence in HepG2 and Huh7 cell lines and the JFH-1 HCV genotype 2a sequence in Huh7 cell lines and measured levels of ISGs and autocrine IFN-β.

The expression of protein kinase R and myxovirus resistance A mRNA was enhanced more with IFN-α and RBV than by IFN-α alone in assays in vivo and in vitro. Such enhancement depended on autocrine IFN-β being enhanced by RBV. RBV upregulated interleukin 8 (IL-8) in the absence of IFN-α. The IL-8 upregulation induced by RBV was responsible for the activation of activator protein 1 (AP-1).

Ribavirin augments the anti-HCV effects of IFN-α induced by ISGs through enhancing autocrine IFN-β. Moreover, RBV can enhance IL-8 through activating AP-1. Improved understanding of ISG modulation by RBV would help to establish a means of eliminating HCV.

Despite years of clinical use and extensive research efforts, the mechanism of action of ribavirin (RBV) is not well understood. Although it has only a mild, transient antiviral effect on HCV replication when administered as monotherapy, when combined with interferon, RBV improves sustained virological response (SVR) rates by approximately 25-30%. Proposed mechanisms of action for RBV against HCV include (1) a direct effect against the HCV RNA dependent RNA polymerase; (2) induction of misincorporation of nucleotides leading to lethal mutagenesis; (3) depletion of intracellular pools via inhibition of inosine monophosphate dehydrogenase; (4) alteration in the cytokine balance between a Th2 profile (anti-inflammatory) to a Th1 profile (pro-inflammatory); and (5) potentiating the effect of interferon via up-regulation of genes involved in interferon signalling. Given the lack of a clear understanding of RBV mechanism of action, it has been challenging to confidently position this drug with new direct antiviral agents (DAA). However, early clinical studies provide strong evidence for a benefit of RBV in combination with DAAs for both IFN containing and sparing regimens. The addition of RBV reduces viral breakthroughs and/or relapses, at least when drugs with low to moderate genetic barriers to resistance are paired together. This is particularly true in patients harbouring HCV subtype 1a. Ongoing studies are now addressing the utility of RBV in nucleoside containing DAA regimens, which offer both potent antiviral activity as well as a high genetic barrier to resistance. It is remarkable that the age-old question of the role of RBV in the future of HCV therapy remains as real today as it was two decades ago.

Ribavirin remains today a pivotal drug in the treatment of hepatitis C; in standard double therapy, as well as in triple combination with direct antiviral agents, ribavirin reduces relapse and can double the sustained virological response obtained with peginterferon alone or in association with direct antiviral agents. In the complex network of interacting factors determining sustained virological response independently of known predictive factors related to host and virus, two modern tools are emerging: polymorphisms in the IL28B gene and very early exposure to ribavirin. The use of a pharmacokinetic-pharmacodynamic model of early ribavirin exposure to adjust the dose individually would help promote a safer ribavirin use and improve sustained virological response. The variability of the influence of ribavirin exposure on anaemia is probably genetically determined; however, the low prevalence of the implicated protective alleles of the inosine triphosphate pyrophosphatase gene could explain their lack of influence on sustained virological response.

Twenty years ago, ribavirin was first used in the treatment for chronic hepatitis C. After few years, ribavirin, in combination with interferon-alpha, showed a dramatic synergistic efficacy against hepatitis C virus infection, leading to viral clearance in about 50% of patients. Recent discovery of potent inhibitors of hepatitis C virus proteases did not replace ribavirin as the mainstay of combination therapy for chronic hepatitis C. Despite this fundamental role of ribavirin, many aspects of the mechanism of action and of the optimal dose and duration of therapy remain to be discovered or settled. In the present review, the authors recall the milestones in the history of ribavirin and try to shed light on the more relevant features of ribavirin action and utilization, and on the clinical problems encountered in managing and optimizing treatment for chronic hepatitis C. Finally, some potential off-label use of this drug in most difficult-to-treat subjects is pointed out. In conclusion, even if a sort of mystery surrounds ribavirin, its efficacy against hepatitis C virus infection fortunately remains lasting and stable.

Hepatitis C is a major cause of liver-related morbidity and mortality. Standard therapy is ribavirin plus pegylated interferon to achieve undetectable level of virus in the blood, but the effect on clinical outcomes is controversial.

To assess the beneficial and harmful effects of ribavirin and interferon combination therapy versus interferon monotherapy for chronic hepatitis C.

We identified trials through electronic databases, manual searches of bibliographies and journals, approaching authors of trials, and pharmaceutical companies until March 2009.

We included randomised trials, irrespective of blinding, language, or publication status, comparing ribavirin plus interferon versus interferon for treatment of chronic hepatitis C.

The primary outcome measures were serum sustained loss of hepatitis C virus, liver-related morbidity plus all-cause mortality, and adverse events. We performed subgroup analyses of patients who were naive, relapsers, or non-responders to previous antiviral treatment. All outcomes were analysed with the random-effects model. We used Peto odds ratios (OR) with 95% confidence intervals (CI) for analysis of morbidity plus mortality. The remaining outcomes were presented as relative risks (RR). We used trial sequential analyses to examine the robustness of our findings.

We included 83 randomised trials with 12,707 patients. Most trials had unclear or high risk of bias. We did not find any significant influence of bias on our results but cannot exclude outcome measure reporting bias as many trials did not report on the primary outcomes of this review. Compared with interferon, ribavirin plus interferon had a significant beneficial effect on sustained virological response in subgroups of naive patients (RR 0.72, 95% confidence interval (CI) 0.68 to 0.75), relapsers (RR 0.62, 95% CI 0.54 to 0.70), non-responders (RR 0.89, 95% CI 0.84 to 0.93), and in all patients (RR 0.75, 95% CI 0.71 to 0.79). Combination therapy significantly reduced morbidity plus mortality in all patients (Peto OR, 0.43, 95% CI 0.23 to 0.79), but not in naive, relapsers, or non-responders individually. Combination therapy significantly increased the risk of haematological, dermatological, gastrointestinal, infectious, and miscellaneous (cough, dyspnoea, fatigue) adverse reactions. Accordingly, combination therapy significantly increased the risk of treatment discontinuation and dose reductions. Trial sequential analyses confirmed our findings regarding virological effects, but not regarding liver-related morbidity and all-cause mortality.

Compared with interferon alone, ribavirin plus interferon is more effective in clearing hepatitis C virus from the blood. Combination therapy may reduce liver-related morbidity and all-cause mortality, but we need more evidence. The number needed to treat to obtain a beneficial effect is considerable considering the increased risk of several severe adverse reactions and costs.

After the discovery of the hepatitis B virus in 1968 and of the hepatitis A virus in 1973, many years were needed to identify the hepatitis C virus (HCV) in 1989. The discovery of HCV was a revolution for hepatology because of the magnitude of the global burden related to HCV infection, a major cause of cirrhosis and hepatocellular carcinoma. Therapy of hepatitis C has rapidly evolved with currently nearly 60% of sustained virological response with the combination of pegylated interferon plus ribavirin. In patients with sustained virological response, viral eradication, corresponding to the cure of infection, and regression of histological liver lesions have been demonstrated. Recently, the availability of in vitro culture systems allowed to characterize viral enzymes, potential therapeutic targets. A novel therapeutic era is open with the protease and polymerase inhibitors, used as a first step in association with pegylated interferon and ribavirin, both to increase efficacy and decrease the risk of resistance. Thanks to these new molecules with a potent antiviral activity, one can reasonably predict a rapid improvement of treatments becoming more efficient and also better tolerated with the progressive replacement of interferon and ribavirin by combinations of these virus specific enzyme inhibitors.

In 2007, the world celebrated the 50th anniversary of the discovery of interferon (IFN) by Isaacs and Lindenmann. Subsequently, the IFN-alpha gene was cloned, fully sequenced and IFN-alpha was produced in recombinant form. Recombinant IFN-alpha is now used as the basis for treatment of chronic hepatitis C virus infection and can also be used to treat certain forms of chronic hepatitis B virus infections. IFNs have also been used in other viral infections, although with less success. The antiviral mechanisms of IFNs are reviewed in this chapter as well as the utility of IFNs in the treatment of persistent viral infections.

This chapter reviews the main chemotherapeutic strategies used against human infections caused by agents responsible for the most important chronic viral illnesses, namely hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV). There is no doubt that most current knowledge about combination antiviral therapy has been developed in the battle against HIV. The availability of more than 20 antiretroviral drugs has permitted to explore their efficacy when given in combination, an opportunity that unfortunately has only been possible since recent years for chronic hepatitis C and still is in the early stages for chronic hepatitis B. However, new antiviral compounds targeting each of these viruses are developed rapidly and will provide further opportunities to explore the efficacy of combination antiviral therapy. While sufficient suppression of HIV RNA and HBV DNA can only be achieved by long-term administration of potent antiviral drugs, HCV RNA may be completely eradicated from the infected individual after a limited duration of treatment.

Ribavirin is an old broad-spectrum antiviral that is highly effective when used in combination with interferon-alpha and also as part of triple therapies containing new inhibitors of the hepatitis C virus (HCV) non-structural (NS)3/4 protease or HCV NS5B polymerase for the treatment of patients with chronic hepatitis C. However, the molecular mechanisms by which ribavirin enhances early and sustained virological response rates during interferon-based antiviral HCV therapy are still unknown. Several mechanisms including (i) immunomodulatory properties, (ii) inhibition of the inosine monophosphate dehydrogenase, (iii) direct inhibition of the HCV-encoded NS5B RNA polymerase, (iv) induction of lethal mutagenesis and (v) modulation of interferon-stimulated gene expression are currently proposed. Here, we discuss recent advances from in vitro data and their importance for the situation in patients with chronic hepatitis C. Furthermore, theoretical aspects from mathematical modelling of ribavirin action in chronic hepatitis C are reviewed.

In 2007, the world celebrated the 50th anniversary of the discovery of interferon (IFN). The first clinical trial of recombinant IFN-alpha in patients with chronic hepatitis C was published in 1986. This article reviews the classification of IFNs, IFN production during viral infections, IFN signaling pathways and the mechanisms of their antiviral and immunomodulatory properties. Hepatitis C virus infection treatment is currently based on the combination of pegylated IFN-alpha and ribavirin. The pegylated IFN-alpha molecules are described, as well as the putative mechanisms of action of ribavirin. Current treatment guidelines are discussed and new results suggesting that the treatment schedule should be tailored to the early virological response during therapy are presented. Finally, insights into new hepatitis C drug developments are given.

Little is known about the potential effects of insertions and deletions (indels) on the evolutionary dynamics of hepatitis C virus (HCV). In fact, the consequences of indels on antiviral treatment response are a field of investigation completely unexplored. Here, an extensive sequencing project was undertaken by cloning and sequencing serum samples from 25 patients infected with HCV subtype 1a and 48 patients with subtype 1b. For 23 patients, samples obtained after treatment with alpha interferon plus ribavirin were also available. Two genome fragments containing the hypervariable regions in the envelope 2 glycoprotein and the PKR-BD domain in NS5A were sequenced, yielding almost 16 000 sequences. Our results show that insertions are quite rare, but they are often present in biologically relevant domains of the HCV genome. Moreover, their frequency distributions between different time samples reflect the quasispecies dynamics of HCV populations. Deletions seem to be subject to negative selection.

Hepatitis C is a major cause of liver-related morbidity and mortality. Ribavirin plus interferon combination therapy is presently considered the optimal treatment of interferon naive patients with chronic hepatitis C, but its role in relapsers and non-responders to previous interferon therapy is not established.

To assess the efficacy and safety of ribavirin alone or in combination with alpha interferon in interferon naive patients, relapsers, and non-responders with chronic hepatitis C.

Eligible trials were identified through searches on electronic databases: The Cochrane Hepato-Biliary Group Controlled Trials Register (August 2001), The Cochrane Controlled Trials Register on The Cochrane Library Issue 3, 2001, MEDLINE (1966 - August 2001), and EMBASE (1985 - August 2001). Manual searches of bibliographies and journals were done as well as authors of trials and pharmaceutical companies producing ribavirin or interferon were contacted.

We included all randomised trials comparing ribavirin with or without alpha interferon versus no intervention, placebo, or alpha interferon for chronic hepatitis C.

The primary outcome measures were the 'sustained' (six months after treatment) virological response, and morbidity plus mortality. The secondary outcome measures were the 'end of treatment' and 'sustained' biochemical response, the 'end of treatment' virologic response, histology, quality of life, and adverse events.

We included eight trials in which 271 patients were randomised to ribavirin versus placebo or no intervention and 48 trials in which 6585 patients were randomised to interferon with or without ribavirin. Compared with placebo or no intervention, ribavirin monotherapy had no significant effect on the virological response or histology and only a transient effect on the biochemical response. Compared with interferon, combination therapy reduced the risk of not having a sustained virological response by 26% in naive patients (relative risk (RR) 0.74; 95% confidence interval (CI) 0.70-0.78), 33% in relapsers (RR 0.67; 95% CI 0.57-0.78), and 11% in non-responders (RR 0.89; 95% CI 0.83-0.96). There was no significant effect on morbidity plus mortality (Peto odds ratio 0.45; 95% CI 0.19-1.06). Irrespective of previous therapy, combination therapy significantly reduced the risk of not having a sustained biochemical response (RR 0.76; 95% CI 0.59-0.84) or improved histology (RR 0.67; 95% CI 0.56-0.81). Combination therapy also significantly increased the risk of treatment discontinuation (RR 1.28; 95% CI 1.07-1.52) and several types of adverse events.

Combination therapy increased the number of naive patients, relapsers, and non-responders with a sustained virological, biochemical, or histological response, but also the occurrence of adverse events.