Peginterferon-alpha-2a (40kD) plus ribavirin: a review of its use in the management of chronic hepatitis C

'It's been a long haul, a big haul, but we've made it': hepatitis C virus treatment in post-transplant patients with virus recurrence: An interpretative phenomenological analysis

The lived experience of both interferon-based and new interferon-free treatments in patients with hepatitis C virus remains understudied. To explore their journey through hepatitis C virus treatment, we interviewed seven post-transplant patients with recurrent hepatitis C virus. Three themes were identified using interpretative phenomenological analysis. Participants reported an ongoing sense of ontological uncertainty characterized by lack of control over their condition and treatment. Furthermore, an apposition of scepticism and hope accompanying each stage of hepatitis C virus treatment was described. A staged approach to psychological intervention tailored to the needs of the patient and their associated 'stage' of hepatitis C virus treatment was recommended.

2015 Philip S. Portoghese Medicinal Chemistry Lectureship. Curing Hepatitis C Virus Infection with Direct-Acting Antiviral Agents: The Arc of a Medicinal Chemistry Triumph

The development of direct-acting antiviral agents that can cure a chronic hepatitis C virus (HCV) infection after 8-12 weeks of daily, well-tolerated therapy has revolutionized the treatment of this insidious disease. In this article, three of Bristol-Myers Squibb's HCV programs are summarized, each of which produced a clinical candidate: the NS3 protease inhibitor asunaprevir (64), marketed as Sunvepra, the NS5A replication complex inhibitor daclatasvir (117), marketed as Daklinza, and the allosteric NS5B polymerase inhibitor beclabuvir (142), which is in late stage clinical studies. A clinical study with 64 and 117 established for the first time that a chronic HCV infection could be cured by treatment with direct-acting antiviral agents alone in the absence of interferon. The development of small molecule HCV therapeutics, designed by medicinal chemists, has been hailed as "the arc of a medical triumph" but may equally well be described as "the arc of a medicinal chemistry triumph".

Viral hepatitis C therapy: pharmacokinetic and pharmacodynamic considerations

Chronic hepatitis C is a global health problem. To prevent or reduce complications, the hepatitis C virus (HCV) infection needs to be eradicated. There have been several developments in treating these patients since the discovery of the virus. As of 1 January 2014, the drugs that are approved for treatment of chronic HCV infection are peginterferon-α, ribavirin, boceprevir, telaprevir, simeprevir and sofosbuvir. In this review we provide an overview of the clinical pharmacokinetic characteristics of these agents by describing their absorption, distribution, metabolism and excretion. In the pharmacodynamic part we summarize what is known about the relationships between the pharmacokinetics of each drug and efficacy or toxicity. We briefly discuss the pharmacokinetics and pharmacodynamics of chronic hepatitis C treatment in special patient populations, such as patients with liver cirrhosis, renal insufficiency or HCV/HIV coinfection, and children. With this knowledge, physicians, pharmacists, nurse practitioners, etc. should be educated to safely and effectively treat HCV-infected patients.

Discovery of daclatasvir, a pan-genotypic hepatitis C virus NS5A replication complex inhibitor with potent clinical effect

The discovery and development of the first-in-class hepatitis C virus (HCV) NS5A replication complex inhibitor daclatasvir (6) provides a compelling example of the power of phenotypic screening to identify leads engaging novel targets in mechanistically unique ways. HCV NS5A replication complex inhibitors are pan-genotypic in spectrum, and this mechanistic class provides the most potent HCV inhibitors in vitro that have been described to date. Clinical trials with 6 demonstrated a potent effect on reducing plasma viral load and, in combination with mechanistically orthogonal HCV inhibitors, established the ability to cure even the most difficult infections without the need for immune stimulation. In this Drug Annotation, we describe the discovery of the original high-throughput screening lead 7 and the chemical conundrum and challenges resolved in optimizing to 6 as a clinical candidate and finally we summarize the results of select clinical studies.

New treatments in hemophilia: insights for the clinician

Hemophilia has evolved from an often fatal hereditary bleeding disorder to a disorder for which safe and effective treatment is available. However, there are several challenges remaining in the treatment of hemophilia. Prophylaxis to prevent bleeding is costly and requires frequent intravenous injections, which are cumbersome for patients. Venous access is often difficult to achieve, especially in small children where central venous lines may need to be implanted. Development of inhibitory antibodies makes treatment of acute bleeds difficult and prophylaxis in patients with inhibitors must also be better addressed. In order to improve treatment, new products are being developed, some of which are already in clinical trials. There are several approaches to prolonging half-lives such as PEGylation, Fc fusion and albumin fusion. Increased activity has been demonstrated in preclinical trials for factor IX and in a human trial with factor VII where the activity of the molecules has been increased by manipulation of the molecular composition. Additional approaches, including blockage of inhibitors of clotting, are also under investigation. Factor VIII and factor IX gene therapy have become a tangible possibility since phase I data recently have been published. Results are promising and there is hope that in the near future substantial progress will be made, perhaps making hemophilia the first genetic condition to be cured.

Single- and Multiple-Dose Pharmacokinetics of Levovirin Valinate Hydrochloride (R1518) in Healthy Volunteers

R1518 is a valine ester prodrug of levovirin as an investigational new drug for the treatment of hepatitis C virus. Two phase 1, single- and multiple-dose studies were conducted to investigate the pharmacokinetics of R1518 in healthy volunteers. After oral dosing, R1518 was rapidly and exclusively converted to levovirin. Levovirin plasma concentrations peaked at 2 hours, with T(1/2) ranging from 6 to 8 hours. The T(1/2) of R1518 was less than 1 hour, with relative exposures (R1518/levovirin) less than 6%. A high-fat meal did not affect the pharmacokinetics. The female groups in both studies had higher plasma levels than males did due to age and renal function difference. An accumulation ratio of 1.3 to 1.5 was observed with the twice-daily regimen. About 75% to 90% of the levovirin equivalent dose was recovered in urine. Increase in exposure was slightly disproportionate to increase in dose. Significantly improved oral absorption of levovirin was achieved following administration of R1518.

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.

Comparison of peginterferon pharmacokinetic and pharmacodynamic profiles

The pharmacokinetics and in dosing regimens of the currently available pegylated interferon (peginterferon) alfa molecules differ greatly, depending on the size and nature of their polyethylene glycol (PEG) moiety. Peginterferon alfa-2a has a branched 40 kDa PEG chain covalently attached to lysine residues and circulates as an intact molecule. On the other hand, peginterferon alfa-2b has a linear 12 kDa PEG chain covalently attached to interferon-a-2b via an unstable urethane bond that is hydrolysed after injection, releasing native interferon alfa-2b. The difference in pegylation between the two peginterferons has a significant impact on their pharmacokinetic properties. Data from comparative and non-comparative studies indicate that peginterferon alfa-2b has a shorter half-life in serum than peginterferon alfa-2a, and a significant proportion of patients receiving peginterferon alfa-2b may have trough concentrations below the limit of detection during the latter part of the 7-day dosing schedule. However, the pharmacodynamic parameters of the two drugs appear to be similar.

Safety and pharmacokinetics of a glycoPEGylated recombinant activated factor VII derivative: a randomized first human dose trial in healthy subjects

BACKGROUND

Extensive research is currently ongoing to prolong the half-life of coagulation factors. One of these techniques is glycoPEGylation, which has also been applied to recombinant activated factor VII (rFVIIa), resulting in a rFVIIa derivative (N7-GP) with a prolonged terminal half-life (t(1/2) ). The main clinical purpose of N7-GP is to provide safe and effective prophylaxis to patients with hemophilia and inhibitors. The prolonged t(1/2) of N7-GP can potentially reduce the dosing frequency and thereby facilitate convenience and compliance, which are two significant barriers to effective prophylaxis.

OBJECTIVES

To determine the safety and pharmacokinetics of single doses of N7-GP in healthy men.

METHODS

 A randomized, placebo-controlled, dose-escalation trial with five cohorts (N7-GP dose of 12.5-100 μg kg(-1) ) was performed. In each cohort, eight subjects were randomized to receive N7-GP (n = 6) or placebo (n = 2).

RESULTS

The mean FVIIa activity was measurable for up to at least 72 h after dosing, and the overall mean t(1/2) for FVIIa activity was 15 h. The pharmacokinetics of N7-GP appeared to be dose-proportional in the dose range investigated. No serious adverse events (including thromboembolic events) were reported. The frequency of adverse events was similar in both the placebo and N7-GP groups. No neutralizing antibodies against N7-GP were detected. A pharmacologic effect was apparent from a dose-dependent statistically significant decrease in the mean prothrombin time in all N7-GP groups as compared with placebo.

CONCLUSIONS

 N7-GP had a plasma half-life of 15 h and a profile that makes it a potential candidate for prophylaxis in patients with hemophilia and inhibitors.

Public and decision maker stated preferences for pharmaceutical subsidy decisions: a pilot study

BACKGROUND

Consideration of public preferences is desirable when making decisions on the subsidy of pharmaceuticals. Little is known about the preferences of the public for pharmaceutical funding decisions, and no study has directly compared the preferences of members of a pharmaceutical decision-making body with those of the public on whose behalf decisions are made.

OBJECTIVE

This article reports the findings of a pilot discrete-choice experiment (DCE) undertaken to test the concept of evaluating the consistency of public and decision maker preferences for the public subsidy of pharmaceuticals.

METHODS

A DCE was used to elicit the relative importance of gains in survival, quality of life (QOL), chance of response success and government costs in pharmaceutical funding decisions, and the impact that the initial severity of illness has on preferences. The DCE was administered to a sample of the Australian public and members of the Pharmaceutical Benefits Advisory Committee and its Economic Subcommittee. A mixed logit model was employed for analysis.

RESULTS

For both samples, increased survival, QOL and chance of response success, and a reduction in cost or uncertainty (decision makers only), increased the likelihood that a pharmaceutical would be chosen for funding. Both samples were more likely to fund a pharmaceutical that was used for the treatment of severe illness.

CONCLUSION

This study sets the foundation for future research on the relative importance of decision criteria, the contexts that impact on the criteria and the extent to which funding decisions for pharmaceuticals in Australia and elsewhere are consistent with the preferences of society.

A magnetic adsorbent-based process for semi-continuous PEGylation of proteins

A semi-continuous magnetic particle-based process for the controlled attachment of PEG (PEGylation) to proteins is described for the first time. Trypsin and 2 kDa mono-activated PEG were used to systematically develop the steps in the process. Proof of concept was shown in a microfluidics system to minimize reagent consumption. Two streams containing (i) 1.2 g/L trypsin and (ii) 4 g/L magnetic adsorbents derivatized with the reversible affinity ligand benzamidine were pumped into a pipe reactor. At the exit, a third solution of activated PEG (0-40 g/L) was introduced and the solutions immediately fed into a second reactor. Upon exiting, the mixture was combined in a third reactor with a fourth stream of free amine groups to stop the reaction (50 mM lysine). The mixture continued into a high-gradient magnetic separator where magnetic supports, with PEGylated trypsin still attached, were captured and washing and elution steps were subsequently carried out. Analysis of the conjugates (with SDS-PAGE & LC-MS) showed that the extent of PEGylation could be controlled by varying the reaction time or PEG concentration. Furthermore, the PEG-conjugates had higher enzyme activity compared to PEGylation of non-immobilized trypsin.

Pegylated interferons for the treatment of chronic hepatitis C: pharmacological and clinical differences between peginterferon-alpha-2a and peginterferon-alpha-2b

Chronic infection with hepatitis C virus (HCV) is a major healthcare problem, affecting an estimated 170 million people worldwide. Interferon-alpha has formed the basis of treatment regimens since the identification of HCV, either alone or in conjunction with the nucleoside analogue ribavirin. The relatively recent introduction of pegylated forms of interferon-alpha, with greater stability and in vivo activity, has substantially improved sustained virological response (SVR) rates compared with unmodified interferon-alpha, with SVR rates of 35-66% when used in conjunction with ribavirin in randomized controlled trials. Two pegylated interferon (peginterferon)-alpha molecules are commercially available for the treatment of chronic hepatitis C, and these differ in the size and nature of the covalently attached polyethylene glycol (PEG) moiety, with resulting differences in pharmacokinetics and in dosing regimens. Peginterferon-alpha-2b has a linear 12 kDa PEG chain covalently attached primarily to histidine-34 of interferon-alpha-2b via an unstable urethane bond that is subject to hydrolysis once injected, releasing native interferon-alpha-2b. The branched, 40 kDa PEG chain of peginterferon-alpha-2a is covalently attached via stable amide bonds to lysine residues of interferon-alpha-2a, and circulates as an intact molecule. Consequently, peginterferon-alpha-2a has a very restricted volume of distribution, longer half-life and reduced clearance compared with native interferon-alpha-2a, and can be given once weekly independently of bodyweight. Peginterferon-alpha-2b has a shorter half-life in serum than peginterferon-alpha-2a and requires bodyweight-based dosing. The majority of head-to-head randomized controlled trials, including the large, randomized IDEAL (Individualized Dosing Efficacy versus Flat Dosing to Assess Optimal Pegylated Interferon Therapy) trial (n = 3070), demonstrated similar SVR rates for peginterferon-alpha-2a and peginterferon-alpha-2b (41% vs 39% in IDEAL), in combination with ribavirin; however, two randomized controlled trials (n = 431 and 320) demonstrated a statistically significant benefit for peginterferon-alpha-2a (66% vs 54%, and 69% vs 54%). Furthermore, two large retrospective studies and one prospective observational study in real-life settings have shown a significant benefit for peginterferon-alpha-2a versus peginterferon-alpha-2b, although SVR rates were generally lower than those seen in controlled trials. The use of interferon-alpha with or without ribavirin is frequently associated with a range of adverse effects, including influenza-like symptoms, haematological changes and neuropsychiatric disturbances, and this is true also of the peginterferons, with similar levels of adverse events, dose reduction and discontinuation from treatment. Peginterferon-alpha-2a and peginterferon-alpha-2b appear from comparative studies to be similarly tolerated, with few differences of clinical significance noted. Peginterferon plus ribavirin, as the standard of care for patients with chronic hepatitis C, may in the future form the basis of improved treatment regimens that include new, targeted anti-HCV agents to increase SVR rates even further.

The utility of therapeutic drug monitoring for ribavirin in patients with chronic hepatitis C--a critical review

OBJECTIVE

To evaluate the utility of therapeutic drug monitoring (TDM) for ribavirin in chronic hepatitis C.

DATA SOURCES

Literature searches were conducted through PubMed (1949-June 2009), EMBASE (1980-June 2009), BIOSIS Previews (1969-June 2009), International Pharmaceutical Abstracts (1970-June 2009), Google, and www.clinicaltrials.gov using the terms ribavirin, therapeutic monitoring, hepatitis C, and drug levels. In addition, pertinent reference citations from identified publications were reviewed. Studies were limited to English language, adult age, and human subjects.

STUDY SELECTION AND DATA EXTRACTION

All articles identified from the data sources were evaluated. Studies that measured ribavirin concentrations or dose and treatment response were included in the review.

DATA SYNTHESIS

While monitoring of ribavirin plasma concentrations to improve treatment response in patients with chronic hepatitis C has been described in the literature, the utility of TDM for ribavirin in this group of patients has not been systematically studied. Thus, a previously published 9-step decision-making algorithm was employed to help determine whether TDM is warranted, based on currently available evidence. Thirty articles involving patients with chronic hepatitis C mono-infection, 12 for hepatitis C-HIV coinfection, 5 for renal dysfunction, and 5 for post-liver transplant patients were reviewed. In all subpopulations, studies exist that either support or refute the usefulness of ribavirin TDM. Additionally, the majority of the included studies had methodologic limitations, such as small sample size, retrospective analyses, and lack of p value adjustment for multiple analyses. Large randomized controlled trials would help to definitively answer this question.

CONCLUSIONS

There is conflicting evidence about the existence of a correlation between ribavirin concentrations and virologic response or development of toxicity. This inconsistent evidence, coupled with the currently employed effective strategies that maximize sustained virologic response and minimize development of anemia, precludes the utility of TDM for ribavirin.

Living with hepatitis C and treatment: the personal experiences of patients

AIM

The purpose of the study was to explore the issues surrounding chronic hepatitis C, combination therapy and its impact on personal relationships to enhance understanding of the experiences of patients living with hepatitis C. This paper focuses on the experiences of the patients and their partners' experiences will be published separately.

BACKGROUND

Patients with chronic hepatitis C who have active inflammatory changes on liver biopsy may undergo combination therapy with interferon and ribavirin. For some patients, the adverse effects of combination therapy are so severe that it can potentially place an enormous stress on personal relationships.

DESIGN

The study was informed by Heideggerian phenomenology.

METHODS

Purposive sampling and semi-structured interviews of five patients and their partners were conducted between 2004-2006 in Sydney Australia, to obtain a rich description of their experiences.

RESULTS

The findings from this study revealed that chronic hepatitis C and combination therapy had an enormous impact on the lives of the patients, their partners and families. The illness and treatment had significant physiological effects that had an impact on quality of life; however, the social and psychological consequences of living with a highly stigmatised disease with an unknown course and outcome cannot be underestimated.

CONCLUSION

The results of this study lend support to the effectiveness of providing equitable services to persons diagnosed with chronic hepatitis C. However, additional research is needed to explore gender, socioeconomic, sexual-orientation, transmission, cultural, religious and genotype differences in this group to address their needs better.

RELEVANCE TO CLINICAL PRACTICE

Nurses play a significant role in educating patients with chronic hepatitis C, advocating for them and helping them to achieve a reasonable state of well being. Through deeper understanding of their experiences of illness and treatment, nurses can move beyond the medical oriented approach to care.

A case of polymyositis in a chronic hepatitis C patient treated with peg-interferon-alpha 2b and ribavirin therapy

Hepatitis C virus (HCV) infection may result in progression to chronic hepatitis, cirrhosis and hepatocellular carcinoma. Interferon-based treatment in patients with chronic hepatitis C may achieve viral clearance, and as a consequence improve liver histology and prevent progression to hepatocellular carcinoma. At present, the recommended therapy for chronic hepatitis C is peg-interferon-alpha (PEG-IFN-α) in conjunction with the oral nucleoside analog ribavirin. In the current study, we report a case of polymyositis associated with chronic hepatitis C following PEG-IFN-α and ribavirin therapy. The patient, a 64-year-old female who was treated with combination therapy, demonstrated elevated serum CPK, AST, ALT and LDH levels at 28 weeks after treatment onset. As there was an elevation of the serum HCV-RNA levels, combination treatment was ceased at 24 weeks. The patient had received IFN therapy twice previously (IFN-α 2a and IFN-α 2b with ribavirin therapy); however, no adverse side effects were observed. Further laboratory examination, muscle biopsy and imaging data suggested polymyositis, possibly triggered by the PEG-IFN-α treatment. The patient was subsequently administered prednisolone and the dose tapered over 7 months. As a result the polymyositis has remained in remission. Although many autoimmune diseases have been associated with IFN therapy, the development of polymyositis is extremely rare.

The lived experience of hepatitis C and its treatment among injecting drug users: qualitative synthesis

Hepatitis C virus infection is a stigmatized condition because of its close association with injecting drug use. There is a need to explore how people who inject drugs (IDUs) perceive hepatitis C, including in relation to treatment experience. We undertook a review, using a qualitative synthesis approach, of English-language qualitative research focusing on the lived experience of hepatitis C among IDUs. The review included 25 published articles representing 20 unique studies. A synthesis of this literature generated three interplaying themes: social stigma, biographical adaptation, and medical and treatment encounters. Interactions with health systems can reproduce stigma linked to drug injecting and hepatitis C, as well as trivialize the lived experience of diagnosis and illness. Hepatitis C can be biographically reinforcing of socially accommodated risk and spoiled identity, as well as disruptive to everyday life. We hypothesize hepatitis C as a liminal illness experience, oscillating between trivial and serious, normalized and stigmatized, public and personal. We conclude by emphasizing the disconnects between the lived experience of hepatitis C among IDUs and Western health care system responses.

Spotlight on peginterferon-alpha-2a (40 kD) plus ribavirin in the management of chronic hepatitis C mono-infection

Peginterferon-alpha-2a (40 kD) [Pegasys(R)] is a conjugate of recombinant interferon-alpha-2a and a 40 kD branched polyethylene glycol (PEG) moiety that is highly active against hepatitis C virus (HCV). Ribavirin (Copegus) is a synthetic nucleoside analog that acts in synergy with the antiviral activity of peginterferon-alpha-2a (40 kD). The combination of subcutaneous peginterferon-alpha-2a (40 kD) once weekly plus oral ribavirin twice daily is widely approved for use in adult patients with chronic hepatitis C, including those with persistently 'normal' ALT activity or HIV-HCV co-infection, and is recommended as a first-line treatment option for patients with chronic hepatitis C and compensated liver disease. In randomized, phase III trials, the combination has consistently demonstrated good therapeutic efficacy (i.e. high sustained virologic response [SVR] rates) and has been generally well tolerated in both treatment-naïve and treatment-experienced patients with chronic hepatitis C, including those with compensated, advanced liver disease. Several baseline and dynamic (on-treatment) predictors of an SVR that can be used to guide and optimize therapy were also determined in these trials and in subsequent analyses. By utilizing these predictors, therapy with peginterferon-alpha-2a (40 kD) plus ribavirin can be individualized to achieve the optimal balance between efficacy and tolerability, further increasing the usefulness of this drug combination. Thus, peginterferon-alpha-2a (40 kD) plus ribavirin remains a valuable therapy in patients with chronic hepatitis C, as a first-line option in those with compensated liver disease and as a second-line therapy in those with advanced liver disease.

Trends in the Treatment of Chronic Hepatitis C Virus Infection

Despite reductions in the incidence of new hepatitis C virus infections, infections from previous decades continue to place a substantial burden on our health care system. Although the course of the disease is highly variable, approximately 20% to 30% of patients develop cirrhosis, end-stage liver disease, or hepatocellular carcinoma. Fortunately, treatment with our current standard of care, peginterferon a and ribavirin, can reduce the complications of chronic liver disease. However, these drugs are associated with significant adverse effects, many patients are ineligible for treatment, and only 50% are cured. Thus, there is a tremendous need to improve our current therapies and develop new compounds for this disease. This review highlights the transmission, pathophysiology, and course of illness; the pharmacokinetics, proposed mechanisms of action, adverse events, and potential drug interactions with peginterferon a and ribavirin; current treatment trends; the role of the pharmacist in the treatment of this disease; and investigational drugs in later stages of clinical development. Despite the initial hope that these new drugs would replace our current standard of care, it has become clear that ribavirin and peginterferon a will continue to play an important role in the treatment of chronic hepatitis C virus in the years to come.

Chronic illness experiences, clinical markers and living with hepatitis C

This study explores the experiences of people with hepatitis C within two models of chronic illness--illness trajectory and shifting perspectives--and examines the effects of clinical markers of disease in relation to perceived health. The findings show some support for both models and suggest how they can be seen as complementary and inter-related. The social consequences of living with hepatitis C, such as potential social limitations and isolation, were more significant and had greater impact than clinical markers of disease progress and should be emphasized in understandings of transformation experiences in chronic illness.

Treatment of hepatitis C virus infection

Acute and chronic hepatitis C virus (HCV) infection remains a serious health problem worldwide, however, there has been advancement in the treatment of HCV infection due to standard treatment using pegylated interferon and ribavirin. The literature indicates that therapy for HCV is becoming more individualized. In addition to considering genotype and viral RNA levels before treatment, achievement of an early virologic response (EVR) and a rapid virologic response (RVR) is now possible during therapy. Moreover, problem patients, such as non-responders, relapsers, HIV or HBV co-infected patients, patients with liver cirrhosis, and pre- or post-liver transplantation patients are an increasing fraction of the patients requiring treatment. This article reviews the literature regarding standard treatments and problem patients with acute and chronic HCV infection. It also includes discussion on contraindications and side effects of treatment with interferon and ribavirin, as well as new drug development.

Viral kinetics in the treatment of chronic hepatitis C

Hepatitis C virus (HCV) is a major cause of chronic hepatitis and hepatic fibrosis, and chronic infection can frequently progress to cirrhosis, end-stage liver disease and hepatocellular carcinoma. Treatment with pegylated interferons (INFs) plus ribavirin has been shown to be more effective than pegylated INFs alone or standard INFs with or without ribavirin. The early response of HCV to treatment with peg-INF has been used to predict treatment outcomes in infected patients, emphasizing the importance of viral kinetics and genotyping in their treatment. Mathematic modelling of viral dynamics has shown the importance of optimal doses of drug, with early virologic response at week 12 predictive of sustained virologic response. Maintaining INF concentration above a therapeutically effective level is necessary to prevent viral rebound and subsequent treatment failure. Once-weekly dosing with peg-INF-alpha2a, which has a longer half-life than other forms of INF, plus daily dosing with ribavirin, has been shown to be effective in reducing viral load.

Representations of people with HIV and hepatitis C in editorials of medical journals: discourses and interdiscursive relations

HIV and hepatitis C are blood-borne viruses that cause chronic diseases and affect (in parts of the developed world) predominantly groups that are marginalized and discriminated against: gay men and injecting drug users, respectively. This paper compares the representation of people with HIV and hepatitis C in editorials of medical journals between 1989 and 2001. Analysis is informed by critical discourse analysis and systemic functional linguistics. Hepatitis C editorials draw almost exclusively on the discourse of biomedicine, and patients are either absent or objects in medical procedures. In HIV editorials, a variety of other discourses are integrated into the discourse of biomedicine, thereby creating multidimensional representations of people with HIV as patients and agents in medical procedures, involved in decision making, affected by economic factors, social and cultural issues. The paper discusses the role of the gay community in discursive change and argues that discursive diversity in the representation of people infected with HIV and hepatitis C in medical journals is necessary for health policy, the professional development of healthcare providers, and media reporting to the general public.

Transport of levovirin prodrugs in the human intestinal Caco-2 cell line

The transport of 10 amino acid ester prodrugs of levovirin (LVV) was investigated in the human intestinal Caco-2 cell line in order to overcome the poor oral bioavailability of LVV, an investigational drug for the treatment of hepatitis C infection. The prodrugs were designed to improve the permeability of LVV across the intestinal epithelium by targeting the di/tri-peptide carrier, PepT1. Caco-2 cell monolayers were employed to study the transport and hydrolysis properties of the prodrugs. Among all mono amino acid ester prodrugs studied, the LVV-5'-(L)-valine prodrug (R1518) exhibited the maximum increase (48-fold) in permeability with nearly complete conversion to LVV within 1 h. Di-amino acid esters did not offer significant enhancement in permeability comparing with mono amino acid esters and exhibited slower conversion to LVV in Caco2 cell monolayers. Pharmacokinetic screening studies of the prodrugs in rats yielded the highest fold increase (6.9-fold) of AUC with R1518 and in general displayed a similar trend to that observed in increases of permeability in Caco-2 cells. Mechanisms involved in the Caco-2 cell transport of R1518 were also investigated. Results of bi-directional transport studies support the involvement of carrier-mediated transport mechanisms for R1518, but not for the LVV-5'-(D)-valine prodrug or LVV. Moreover, the permeability of R1518 was found to be proton dependent. PepT1-mediated transport of R1518 was supported by results of competitive transport studies of R1518 with the PepT1 substrates enalapril, Gly-Sar, valganciclovir, and cephalexin. R1518 was also found to inhibit the permeability of valganciclovir and cephalexin. These results suggest that R1518 is a PepT1 substrate as well as an inhibitor.

Chronic hepatitis C virus infection: Is there a correlation between HCV genotypes and the level of viremia?

Introduction. Hepatitis C virus (HCV) RNA status and HCV genotypes have become extremely important for exact diagnosis, prognosis, duration of treatment and monitoring of antiviral therapy of chronic HCV infection. Material and methods. For the purpose of precise and objective assessment of virologic analyses, such as the determination of the number of virus copies and virus genotypes, 110 patients with chronic HCV infection were tested. Genotyping of HCV isolates and HCV RNA quantification were performed by using the PCR method. Genotype lb infection was verified in 49.1% of patients, genotype 3a infection was found in 28.2%, genotype 4 in 9.1%, genotype 2 in 4.5%, while mixed genotype infections were diagnosed in 9.1% of cases. Results. Patients infected by genotype lb had significantly higher serum HCV RNA level in relation to patients infected by other genotypes (p<0.05). Over 70% of patients infected by genotype lb had more than 2xl06 virus copies in 1 ml of blood, while in genotypes 2, 3a and 4, the percentage was 40%, 38.5% and 30%, respectively. Male patients had approximately 7.7x10.6 virus copies in 1 ml of blood, which was significantly higher in comparison with female patients (2.3xl06 copies/ml; p<0.05). Conclusion. Our results are in concordance with the results of other authors reporting that genotype lb is predominant in Europe, as well as significantly higher incidence of viremia in patients with genotype lb infection in relation to other HCV genotypes. Based on these results, we can conclude that our patients, most commonly, present with severe clinical course of chronic HCV infection and require longer treatment (48 weeks), which causes economic problems. .

Patient education and treatment strategies implemented at a pharmacist-managed hepatitis C virus clinic

Hepatitis C virus (HCV) infection is a major public health concern. Approximately 4 million people in the United States have been infected with the virus, and up to 85% of them will develop chronic infection. Chronic HCV infection has often been associated with progression of hepatic fibrosis and, in some cases, cirrhosis and end-stage liver disease. The standard of care is combination therapy with pegylated interferon (peginterferon) alfa plus ribavirin. More than 50% of patients with HCV treated with combination therapy achieve a sustained viral response, defined as undetectable hepatitis C viral RNA 6 months after the end of therapy. Effective patient education and drug therapy management are critical in enabling patients to adhere to the treatment regimen, which is either 24 or 48 weeks long, depending on the virus strain. The drug regimen is associated with several possible adverse events as well as weekly subcutaneous administration (of peginterferon alfa). Frequent monitoring of patients and, often, adjustments in the dosage of one or both components of the therapy are necessary during the treatment course. Strategies used by clinical pharmacists at an HCV clinic are discussed that can facilitate a successful treatment outcome for patients with HCV treated with combination therapy, while enabling them to maintain a reasonable quality of life.

Treatment of genotype 2 and 3 chronic hepatitis C virus-infected patients

AIM

Before pegylated interferon alpha (IFN) was introduced for the therapy of chronic hepatitis C virus (HCV)-induced hepatitis, conventional thrice weekly IFN therapy was supplemented by ribavirin. Also, at that time, higher and more frequent doses of IFN were expected to be more effective than the standard regimen of 3 MU thrice weekly. As ribavirin significantly increases side effects and negatively influences the quality of life particularly in young patients, we started a prospective non-randomized study with a daily IFN-2a monotherapy as an initial treatment for chronic hepatitis C.

METHODS

Forty-six consecutive chronic HCV-infected patients received 3 MU IFN-2a per day as an initial treatment. Patients with genotype 2 or 3 (n = 12) were treated for 24 wk, and patients with genotypes other than 2 or 3 (n = 34) for 48 wk. Treatment outcome was followed up for 48 wk after the end of treatment (EOT). Virological response was defined as the absence of detectable serum HCV-RNA. Patients without virological response at 12 wk after the start of treatment received low-dose ribavirin (10 mg(kg/d)) additionally.

RESULTS

During treatment, three genotype 3 patients were excluded from the study due to incompliance. The remaining patients (n = 9) infected with genotype 2 or 3 showed an initial virological response rate of 100%. Six patients (66.7%) were still found to be virus-free at the end of follow-up period. In these patients, initial virological response was evident already after 2 wk of treatment. In contrast, initial virological response occurred first after 4 wk of treatment in the three patients who relapsed (33.3%). In comparison, patients infected with genotypes other than 2 or 3 (n = 34) showed an initial virological response rate of only 23.5% (n = 8), and even in combination with ribavirin a sustained virological response (SVR) rate of only 11.8% (n = 4) could be achieved.

CONCLUSION

In chronic HCV-infected patients with genotype 2 or 3, a SVR can be expected after 24 wk of daily dose IFN-2a treatment without ribavirin, if initial virological response develops early. This finding is worth to be confirmed in a prospective randomized study with pegylated IFN.

Hepatitis C virus RNA kinetics during the initial 12 weeks treatment with pegylated interferon-alpha 2a and ribavirin according to virological response

To optimize treatment of chronic hepatitis C early identification of patients who will not achieve a sustained virological response (SVR) is desirable. We investigated hepatitis C virus (HCV) RNA kinetics at day 1 (in 15 patients; genotypes 1 and non-1, 9 and 6 respectively) at weeks 1, 4 and 12 (in 53 patients; genotypes 1 and non-1, 19 and 34, respectively) during treatment with pegylated interferon alpha-2a and ribavirin. Patients with SVR had a significantly more pronounced mean log10 decline from baseline in HCV RNA levels at weeks 1 and 4 compared with patients who failed to achieve SVR (1.99 vs 0.85 at week 1, P = 0.0003 and 2.89 vs 1.72 at week 4, P = 0.0159), whereas no difference was noted after day 1. For patients with a 2-log10 decrease in HCV RNA levels at day 7, the positive predictive value (PPV) for a SVR was 92%, whereas week 12 was the best time point for predicting a later nonresponse [negative predictive value (NPV) 92%] in patients failing to achieve a 2-log10 drop. For patients with genotype non-1 and a 2-log10 decrease in HCV RNA levels the PPV for a SVR was 89% week 1, and 79% weeks 4 and 12. The corresponding NPV for patients with genotype non-1 were 43, 40 and 100% respectively. During treatment with pegylated interferon alpha-2a plus ribavirin the HCV RNA decline at week 1 was an accurate predictor of SVR in patients who had achieved a 2-log10 drop in HCV RNA levels, whereas the lack of such decline week 12 was an accurate marker of a nonresponse.

Peginterferon Alpha/Ribavirin Combination Therapy for the Treatment of Hepatitis C Infection

Chronic infection with the hepatitis C virus is widespread in the United States. This disease is associated with a progression of fibrosis of the liver leading to liver cirrhosis in as many as 20% of cases. The current standard of care for the treatment of chronic hepatitis C infection is combination therapy with pegylated interferon alpha plus ribavirin. In more than 50% of patients, this regimen has been shown to induce a sustained viral response, defined as undetectable hepatitis C viral ribonucleic acid (RNA) for 6 months after the end of treatment. Typically, patients are treated for 24 or 48 weeks. A number of possible adverse events are associated with combination therapy, and patient empowerment through supportive nursing care is critical to facilitating patient adherence to treatment. This article provides an update on information concerning the diagnosis and treatment of chronic hepatitis C infection. This information can be tailored to provide patient-focused assessment, education, and treatment.

The experience of interferon-based treatments for hepatitis C infection

Clinical trials of interferon-based treatments for hepatitis C infection show decrements in patients' health-related quality of life due to side effects of therapy. The impact of side effects on patients' overall quality of life still remains unclear. To explore this issue, the authors interviewed people living in New South Wales, Australia, who had undergone treatment for hepatitis C. Their aim in this article is to report participants' experiences of treatment side effects. In Australia, this information is important, because a new interferon-based regimen has been adopted as the mainstay of hepatitis C treatment, and it is predicted that many more people will seek treatment. The authors argue for further qualitative research to enhance knowledge of the impact of this therapy.

High versus standard doses interferon-alpha in the treatment of naïve chronic hepatitis C patients in Taiwan: a 10-year cohort study

BACKGROUND

Interferon-alpha monotherapy is effective in less than one-third patients with chronic hepatitis C. The dose-effect, tolerability and durability of interferon-alpha treatment and its long-term effect on the prevention of cirrhosis and hepatocellular carcinoma in naive Taiwanese patients with chronic hepatitis C have not been well investigated. We conducted the present cohort study treated with high and standard interferon-alpha to illustrate the issues.

METHODS

We performed a long-term virologic and histological follow-up of 214 chronic hepatitis C patients treated with interferon-alpha, 3 million units (3-MU, n = 80) or 6-MU (n = 134) thrice weekly for 24 weeks, in Taiwan between 1992 and 2001.

RESULTS

There was no difference in the incidence of discontinuation between 3-MU and 6-MU groups (4/80, 5.0% versus 10/134. 7.5%). The 6-MU group had similar incidence of adverse events with the 3-MU group, except that 6-MU group had significantly higher incidence of psychological manifestations, mainly presented as irritability. The rates of sustained virological response (SVR) were significantly higher in 6-MU regimen (37.1%) than in 3-MU regimen (23.7%, p < 0.05) in per protocol analysis. Based on multivariate analysis, baseline viral load was strongly associated with SVR, followed by hepatitis C virus genotype, interferon-alpha regimen, and liver fibrosis. A histological improvement in necroinflammatory activity, but not in fibrosis was observed in the follow-up biopsy performed 0.5-5.5 years (mean: 1.9 years, n = 51) after end-of-treatment. Among patients without SVR, there was more activity improvement in 6-MU group. The durability of SVR was 100% (18/18) and 97.8% (45/46) for 3-MU and 6-MU group, respectively, in a mean follow-up period of 6.81 years (5.25-9.18 years). For 163 baseline non-cirrhotic patients, 9 of 84 (10.7%) non-responders and 3 of 79 (3.8%) sustained responders progressed to cirrhosis during a mean follow-up period of 5.52 and 5.74 years, respectively (p = 0.067, Kaplan-Meier survival analysis, log-rank test). For all 200 patients, hepatocellular carcinoma was detected in 12 of 113 (10.6%) non-responders and one of 87 (1.1%) sustained responders during a mean follow-up period of 5.67 and 5.73 years, respectively (p < 0.01, Kaplan-Meier survival analysis, log-rank test).

CONCLUSION

We confirm the dose effect of interferon-alpha in chronic hepatitis C. Six-MU regimen had better efficacy than 3-MU regimen in virologic and histological responses. Both regimens had good tolerability and durability in Taiwan. Sustained response could reduce the incidence of cirrhotic change and hepatocarcinogenesis.

Efficacité et tolérance de l'association interféron pégylé-ribavirine chez les patients co-infectés VIH-VHC en pratique clinique : étude observationnelle de 32 patients

OBJECTIVE

To describe efficacy and safety in clinical practice of pegylated interferon plus ribavirin (INFpeg-Riba) in the treatment of hepatitis C viral infection (HCV) in HIV infected patients.

METHODS

Monocentric retrospective study with inclusion of all patients who received at least once INFpeg-Riba before April 1st 2003. All patients were followed up to six months after the end of HCV therapy.

RESULTS

Thirty two HIV-positive patients (23 men and 9 women) with chronic hepatitis C treated by INFpeg-Riba were included. The mean age was 43 years. Fourteen patients carried HCV genotype 2 or 3 (43 %) and 18 patients carried genotype 1 or 4 (57%). The Metavir score of fibrosis showed fibrosis F1 (N =3), F2 (N =14), F3 (N =7) and F4 - cirrhosis (N =8). Twenty six patients (81%) were naive for anti hepatitis C drugs. Thirty one per cent of patients were at AIDS stage and 84% were receiving antiretroviral drugs. The mean CD4 cell count was 469 /ml and the plasma RNA HIV was less than 50 copies /ml in 57% of the cases. Adverse events leading to reduction of dose of drugs occurred in 40% and adverse events leading to discontinuation treatment occurred in 12%. A decline of CD4 cell count <200 CD4/ml was observed in 15%. Clearance of HCV-RNA in end of treatment was seen in 46 % and sustained virological response in 34 %. The main predictors of sustained virological response were HCV genotype 2 or 3 (P =0.04) and plasma HIV RNA less than 50 copies/ml (P =0.001). The predictive value of good virological response of a CD4 cell count >350/ml before treatment was very near the statistical significancy (p =0.07).

CONCLUSIONS

The efficacy of pegylated interferon plus ribavirin in HIV-HCV co-infected patients is disappointing mainly due to a poor tolerance. In addition to HCV genotype, plasma HIV RNA level and CD4 cell count were essential to predict INFpeg-Riba response and should be taken into account in the process leading to the initiation of such therapy in HIV-HCV co-infected patients.

Peginterferon-alpha-2a (40kD) plus ribavirin: a review of its use in hepatitis C Virus And HIV co-infection

Pegylated interferon plus ribavirin is the standard first-line treatment in patients with chronic hepatitis C virus (HCV) mono-infection. Although the optimal anti-HCV regimen is not established in the more difficult-to-treat population with HIV-HCV co-infection, much of the data in this clinical setting have been derived from studies evaluating peginterferon-alpha-2a (40kD) [Pegasys] plus ribavirin (Copegus), most notably the APRICOT (AIDS Pegasys Ribavirin International Co-Infection Trial) and the ACTG (AIDS Clinical Trial Group) A5071 study. In particular, results of APRICOT - the largest study conducted to date with a pegylated interferon plus ribavirin in patients with HIV-HCV co-infection - indicate that a substantial proportion of patients will achieve sustained virological response (SVR) at week 72 when these drugs are administered for 48 weeks in an appropriate dosage regimen. In general, the tolerability profile of peginterferon-alpha-2a plus ribavirin in APRICOT was similar to that previously reported in patients with HCV mono-infection.

Chronic hepatitis C treatment patterns in African American patients: an update

There are large racial disparities in the incidence of chronic hepatitis C virus (HCV) infection in the United States. The prevalence of HCV, and the prevalence of infection with HCV genotype 1, is higher among African Americans than among other ethnic groups. African Americans also have a higher incidence of complications of HCV infection, including a higher incidence of antibodies to HCV RNA and higher incidences of occurrence of and mortality from hepatocellular carcinoma. Combination therapy with pegylated interferons and ribavirin has increased the sustained virologic response (SVR) rates, and decreased the rates and severity of adverse events, over those observed with standard interferons, with or without ribavirin, although SVR rates with peginterferons plus ribavirin are lower in African Americans than in other ethnic groups. A recent clinical trial of peginterferon alpha-2a plus ribavirin in African American patients resulted in a higher SVR rate, 26%, than observed previously, and 90% of patients showed stabilization or improvement in fibrosis. No host or viral genetic differences have yet been identified to explain the racial disparities in incidence of HCV or response to treatment, but clinical trials are currently ongoing to identify these factors. Because treatment with pegylated interferons plus ribavirin yields improved SVR rates with good tolerability, while the basis for lower response rates in African Americans is not yet known, it is recommended that all patients with chronic HCV infection, regardless of ethnic or racial background, receive combination therapy.