A dose-ranging study of pegylated interferon alfa-2b and ribavirin in chronic hepatitis C. The Hepatitis C Intervention Therapy Group

Therapeutic potential of gene therapy for gastrointestinal diseases: Advancements and future perspectives

Advancements in understanding the pathogenesis mechanisms underlying gastrointestinal diseases, encompassing inflammatory bowel disease, gastrointestinal cancer, and gastroesophageal reflux disease, have led to the identification of numerous novel therapeutic targets. These discoveries have opened up exciting possibilities for developing gene therapy strategies to treat gastrointestinal diseases. These strategies include gene replacement, gene enhancement, gene overexpression, gene function blocking, and transgenic somatic cell transplantation. In this review, we introduce the important gene therapy targets and targeted delivery systems within the field of gastroenterology. Furthermore, we provide a comprehensive overview of recent progress in gene therapy related to gastrointestinal disorders and shed light on the application of innovative gene-editing technologies in treating these conditions. These developments are fueling a revolution in the management of gastrointestinal diseases. Ultimately, we discuss the current challenges (particularly regarding safety, oral efficacy, and cost) and explore potential future directions for implementing gene therapy in the clinical settings for gastrointestinal diseases.

Therapeutic strategies and promising vaccine for hepatitis C virus infection

Hepatitis C virus (HCV) infection is still a significant global health problem despite therapeutic advancements. Ribavirin and interferon therapy have been the sole available treatments for HCV infection for a number of years with low efficacy. Thus, currently, a number of therapeutic strategies are being used, including nanoparticles (NPs), micro-RNAs such as small interfering RNA (siRNA), RNAi-based gene silencing and antisense oligonucleotide-based microRNA-122, microRNA-155, and short hairpin RNAs (shRNAs), and immunotherapeutic approaches such as anti-programmed cell death 1(PD-1), monoclonal antibodies (mAb or moAb), and monocyte-derived dendritic cells (Mo-DCs). Furthermore, direct-acting antivirals (DAAs) and host-targeting agents (HTA) were also the current therapeutic approaches with great efficacy. In spite of different clinical trials on HCV vaccine developments, nowadays there is no effective HCV vaccine in opposition to virus due to various challenges including genetic diversity, lack of immunocompetent small animal models, shortage of HCV vaccination testing alternatives, lack of an effective tissue culture method for replicating HCV, and inadequate knowledge regarding to immune responses against HCV infection. Nowadays, mRNA vaccine, recombinant viral vector, peptides vaccine, virus-like particles, DNA vaccine, rational designed vaccine, and recombinant polyantigenic T-cell-based vaccine are novel promising candidates for HCV vaccine based on various clinical trials. This review summarizes the different therapeutic approaches and the advancements of vaccine candidates for HCV infection.

Advances in engineering and delivery strategies for cytokine immunotherapy

INTRODUCTION

Cytokine immunotherapy is a growing field for the treatment of cancer, infectious disease, autoimmunity, and other ailments. Therapeutic cytokines are a class of secreted, small proteins that play a pivotal role in regulating the innate and adaptive immune system by provoking or mitigating immune responses. In the clinic, cytokines are frequently combined with other treatments, such as small molecules and monoclonal antibodies. However, the clinical translation of cytokine therapies is hindered by their short half-life, pleiotropic nature, and off-target effects, which cause diminished efficacy and severe systemic toxicity. Such toxicity limits dosage, thus resulting in suboptimal doses. Accordingly, numerous efforts have been devoted to exploring strategies to promote cytokine therapies by improving their tissue specificity and pharmacokinetics.

AREAS COVERED

Preclinical and clinical research into bioengineering and delivery strategies for cytokines, consisting of bioconjugation, fusion proteins, nanoparticles, and scaffold-based systems.

EXPERT OPINION

These approaches pave the way for the development of next-generation cytokine treatments with greater clinical benefit and reduced toxicity, circumventing such issues currently associated with cytokine therapy.

Continuous sensing of IFNα by hepatic endothelial cells shapes a vascular antimetastatic barrier

Hepatic metastases are a poor prognostic factor of colorectal carcinoma (CRC) and new strategies to reduce the risk of liver CRC colonization are highly needed. Herein, we used mouse models of hepatic metastatization to demonstrate that the continuous infusion of therapeutic doses of interferon-alpha (IFNα) controls CRC invasion by acting on hepatic endothelial cells (HECs). Mechanistically, IFNα promoted the development of a vascular antimetastatic niche characterized by liver sinusoidal endothelial cells (LSECs) defenestration extracellular matrix and glycocalyx deposition, thus strengthening the liver vascular barrier impairing CRC trans-sinusoidal migration, without requiring a direct action on tumor cells, hepatic stellate cells, hepatocytes, or liver dendritic cells (DCs), Kupffer cells (KCs) and liver capsular macrophages (LCMs). Moreover, IFNα endowed LSECs with efficient cross-priming potential that, along with the early intravascular tumor burden reduction, supported the generation of antitumor CD8+ T cells and ultimately led to the establishment of a protective long-term memory T cell response. These findings provide a rationale for the use of continuous IFNα therapy in perioperative settings to reduce CRC metastatic spreading to the liver.

Reservoir-Style Polymeric Drug Delivery Systems: Empirical and Predictive Models for Implant Design

Controlled drug delivery systems can provide sustained release profiles, favorable pharmacokinetics, and improved patient adherence. Here, a reservoir-style implant comprising a biodegradable polymer, poly(ε-caprolactone) (PCL), was developed to deliver drugs subcutaneously. This work addresses a key challenge when designing these implantable drug delivery systems, namely the accurate prediction of drug release profiles when using different formulations or form factors of the implant. The ability to model and predict the release behavior of drugs from an implant based on their physicochemical properties enables rational design and optimization without extensive and laborious in vitro testing. By leveraging experimental observations, we propose a mathematical model that predicts the empirical parameters describing the drug diffusion and partitioning processes based on the physicochemical properties of the drug. We demonstrate that the model enables an adequate fit predicting empirical parameters close to experimental values for various drugs. The model was further used to predict the release performance of new drug formulations from the implant, which aligned with experimental results for implants exhibiting zero-order release kinetics. Thus, the proposed empirical models provide useful tools to inform the implant design to achieve a target release profile.

Type I interferon therapies of multiple sclerosis and hepatitis C virus infection

Interferons type I (IFN-I), activated following a bacterial or viral infection, play a major role in the induction and regulation of the immune system. The immune response results in viral RNA and binds to receptors such as RIG-I-like receptors (RLRs) or Toll-like receptors, leading to the IFN-I signaling cascade. Thanks to its cellular function, IFN-I is widely used in therapies for such diseases as multiple sclerosis (MS) and hepatitis C disease (HCD).

MS is a neurological, autoimmune, chronic inflammatory disease of the central nervous system (CNS). During MS, nerve cell demyelination is observed due to the myelin heaths and oligodendrocyte damage. As a result, neuronal signal and neuron communication are attenuated. The mechanism of MS is still unknown. MS therapy applies interferon-β (IFN-β). IFN-β therapy has been used since the last century, but the therapeutic mechanism of IFN-β has not been completely understood. MS can lead to four syndromes: clinically isolated syndrome (CIS), relapsing-remitting MS (RRMS), primary progressive MS (PPMS), and secondary progressive MS (SPMS).

HCD occurs as a result of infection with the hepatitis C virus (HCV), belonging to the Flaviviridae family. HCV is a blood-borne virus with a positive single-stranded RNA. A vaccine for HCV is not available yet. HCD can lead to liver damage or cancer. In HCD interferon-α therapy (IFN-α) is applied. As with MS, the mechanism of IFN-α therapy is not completely known.

Update on Diagnosis and Management of Conjunctival Papilloma

Conjunctival papilloma is an acquired benign squamous cell tumor that can present at any age, but most frequently in the third and fourth decades of life. Papillomas have been associated with human papilloma virus (HPV) infection, usually types 6 and 11. Although histopathological diagnosis remains the gold standard, the advent of newer non-invasive imaging modalities such as optical coherence tomography (OCT) is transforming the way we diagnose and treat ocular surface tumors, including conjunctival papilloma. Management of these lesions can prove a challenge to the treating physician since not all lesions respond to medical and/or surgical therapy and in fact may worsen after surgical manipulation. In this review, the epidemiology, pathophysiology, clinical characteristics, and diagnosis of conjunctival papilloma including the use of OCT are discussed. Indications, efficacy, and side effects of currently available management options are also reviewed to guide the selection of the best treatment approach.

Predictive value of IL-28B rs12979860 variants for peg-IFN, sofosbuvir plus ribavirin treatment of HCV infection in Pakistani population

AIM

The correlation of IL28-B genetic variants (rs12979860) with combinational therapy (peg-interferon, sofosbuvir plus ribavirin) of hepatitis C virus infection were studied in 154 chronic hepatitis C patients.

METHODS & RESULTS

The sustained virological response for efficient antiviral regimen was achieved in 75.32% treated individuals. Three genotypes of rs12979860 (CC, CT and TT) were compared both in sustained virological response and nonresponders groups (p = 0.25, p ≤ 0.001, p = 0.10, respectively). CT genotype demonstrated a significant correlation (p ≤ 0.001) in both groups with higher positive predictive value (81.55%).

CONCLUSION

IL28 polymorphism and positive predictive value may be considered as the markers for the evaluation of the effectiveness of the treatment regimen. Further clinical trials are recommended to verify the role of IL28-B in hepatitis C virus treatment.

Genetic predictors of the response to the treatment of hepatitis C virus infection

The genome-wide association studies have identified a strong association between interleukin 28B (IL28B) gene polymorphisms and the response to treatment in patients with hepatitis C virus (HCV) infection. The aim of the study was to evaluate the association between three most widely studied IL28B gene polymorphisms and the response to antiviral treatment of chronic hepatitis C. We performed the genotyping of the three IL28B gene polymorphisms: rs12979860, rs8099917, and rs12980275 in 72 Caucasian patients with chronic hepatitis C, previously treated with the combination therapy of pegylated interferon alpha (PEGIFN α) and ribavirin (RBV). The patients included in the study had finished the treatment regimen at least 6 months before enrolling in the study. We used the sustained viral response (SVR) for the evaluation of the effectiveness of the antiviral treatment, and it was tested with an assay with a sensitivity of 20 IU/mL. An SVR was achieved in 59.7% (43/72) of the treated patients. The three IL28B gene polymorphisms (CC genotype of rs12979860, TT genotype of rs8099917, and AA genotype of rs12980275) were associated with the SVR (p=0.029, p=0.016, and p=0.028, respectively) in the study patients with chronic hepatitis C treated with the combination therapy of PEGIFN α and RBV. The association of IL28B gene polymorphisms with the treatment response points to the possibility of personalized medicine for the treatment of HCV infection.

Barriers to hepatitis C antiviral therapy in HIV/HCV co-infected patients in the United States: a review

This review synthesized the literature for barriers to HCV antiviral treatment in persons with HIV/HCV co-infection. Searches of PubMed, Embase, CINAHL, and Web of Science were conducted to identify relevant articles. Articles were excluded based on the following criteria: study conducted outside of the United States, not original research, pediatric study population, experimental study design, non-HIV or non-HCV study population, and article published in a language other than English. Sixteen studies met criteria and varied widely in terms of study setting and design. Hepatic decompensation was the most commonly documented absolute/nonmodifiable medical barrier. Substance use was widely reported as a relative/modifiable medical barrier. Patient-level barriers included nonadherence to medical care, refusal of therapy, and social circumstances. Provider-level barriers included provider inexperience with antiviral treatment and/or reluctance of providers to refer patients for treatment. There are many ongoing challenges that are unique to managing this patient population effectively. Documenting and evaluating these obstacles are critical steps to managing and caring for these individuals in the future. In order to improve uptake of HCV therapy in persons with HIV/HCV co-infection, it is essential that barriers, both new and ongoing, are addressed, otherwise, treatment is of little benefit.

A phase I, dose-escalation study of cyclical weekly oral temozolomide and weekly PEG-interferon alpha-2b in patients with refractory or advanced solid tumours

BACKGROUND

Temozolomide (TMZ) is an oral alkylating agent used in the treatment of central nervous system neoplasms and metastatic melanoma. Preclinical and clinical data suggested that combining TMZ with interferon alpha-2b (IFN-alpha-2b) may result in increased anti-tumour efficacy.

METHODS

This was a phase I, dose-escalation study to define the maximum tolerated dose (MTD) and dose-limiting toxicities (DLT) of cyclical oral TMZ (days 1-7 and 15-21) in combination with pegylated IFN-alpha-2b (PEG-IFN-alpha-2b) in patients with advanced solid tumours.

RESULTS

We treated 19 patients (10 female and nine male), median age 58 years (range: 41-79 years). Ten patients tolerated TMZ at 100 mg/m² on days 1-7 and 15-21 plus PEG-IFN-alpha-2b at 1.5 mcg/kg/week on 28-day cycles which was the MTD of the combination. The pharmacokinetic parameters of PEG-IFN-alpha-2b were not altered by TMZ, at the MTD.

CONCLUSION

The MTD of cyclical oral TMZ was 100 mg/m² on days 1-7 and 15-21 when combined with weekly subcutaneous PEG-IFNα-2b at 1.5 mcg/kg/week on 28 days cycles. The PK of PEG-IFN-alpha-2b appeared consistent with those when it is used as monotherapy.

Inhibition of hepatitis C virus infection by polyoxometalates

Hepatitis C virus (HCV) infects about 2% of the world population. The standard treatment of chronic HCV infection is still discontented because of the low sustained virological response rate. The development of new HCV antivirals is a healthcare imperative. We explored the potentials of polyoxometalates to inhibit HCV infection using newly developed HCVcc cell culture system. We found one polyoxometalate compound (named POM-12) can inhibit HCV infection at the nanomolar range while displayed little cytotoxicity. We showed that POM-12 inhibited pseudotyped HCV infection but had no effect on HCV RNA replication. Furthermore, we showed that POM-12 was virucidal and can disrupt HCV particles. Finally we demonstrated that POM-12 had no effect on the vesicular stomatitis virus infection while had weak inhibitory activity against the influenza virus infection. In conclusion, we identified a potent anti-HCV compound which may provide an attractive drug candidate to cure HCV infection.

Meta-analysis: mortality and serious adverse events of peginterferon plus ribavirin therapy for chronic hepatitis C

BACKGROUND

Pegylated interferon (PEG-IFN) plus ribavirin (RBV) therapy is the current standard of care for patients with chronic hepatitis C. Determining precisely the risk of serious adverse events (SAEs) and mortality from a single study is rather difficult because of the infrequency of such events. The aim of this systematic review was to assess the rates of SAEs and the mortality of PEG-IFN/RBV therapy in a pooled large sample, and to assess the relationship between SAEs and mortality rates and therapeutic characteristics.

METHODS

A literature search was conducted using MEDLINE, EMBASE, and the Cochrane Library to identify randomized controlled trials evaluating the efficacy and safety of PEG-IFN/RBV therapy. We calculated the crude mortality and SAE rates with 95% confidence intervals (CIs).

RESULTS

Eighty studies with 153 treatment arms that included 27569 patients were enrolled (14401 patients treated with Peg-IFN alpha-2a/RBV and 13168 with Peg-IFN alpha-2b/RBV). All-cause and treatment-related deaths were observed in 50 (0.18%; 95% confidence interval [CI] 0.13-0.24%) and sixteen (0.058%; 95% CI 0.033-0.094%) patients, respectively. The crude SAE rate was 7.08% (95% CI 6.75-7.41%). Subgroup analysis revealed higher SAE rates in patients receiving PEG-IFN alpha-2a than in those with PEG-IFN alpha-2b (7.45 vs. 6.74%), and higher SAE rates with higher doses than with the lower doses in PEG-IFN-2a and 2b (11.94 vs. 6.99%, 7.10 vs. 5.05%, respectively), and with extended duration (> 48 weeks) than with standard duration (48 weeks) (15.5 vs. 6.67%) in PEG-IFN alpha-2a.

CONCLUSION

The mortality rate during PEG-IFN/RBV therapy was acceptably low, but the rate of SAEs was not negligible in a treatment for a benign disease, and the rate was affected by treatment regimens.

Nanotechnology in therapeutics: a focus on nanoparticles as a drug delivery system

Continuing improvement in the pharmacological and therapeutic properties of drugs is driving the revolution in novel drug delivery systems. In fact, a wide spectrum of therapeutic nanocarriers has been extensively investigated to address this emerging need. Accordingly, this article will review recent developments in the use of nanoparticles as drug delivery systems to treat a wide variety of diseases. Finally, we will introduce challenges and future nanotechnology strategies to overcome limitations in this field.

Direct acting antivirals for the treatment of chronic viral hepatitis

The development and evaluation of antiviral agents through carefully designed clinical trials over the last 25 years have heralded a new dawn in the treatment of patients chronically infected with the hepatitis B and C viruses, but not so for the D virus (HBV, HCV, and HDV). The introduction of direct acting antivirals (DDAs) for the treatment of HBV carriers has permitted the long-term use of these compounds for the continuous suppression of viral replication, whilst in the case of HCV in combination with the standard of care [SOC, pegylated interferon (PegIFN), and ribavirin] sustained virological responses (SVRs) have been achieved with increasing frequency. Progress in the case of HDV has been slow and lacking in significant breakthroughs.This paper aims to summarise the current state of play in treatment approaches for chonic viral hepatitis patients and future perspectives.

Treatment of hepatitis C cryoglobulinemia: mission and challenges

Mixed cryoglobulinemia (MC) is a syndrome resulting from cold-insoluble immunoglobulin complexes or cryoglobulins (CGs) that precipitate in the serum of 40% to 50% of patients with chronic hepatitis C virus (HCV) infection. The pathogenesis of cryoglobulinemia likely occurs due to chronic viremia and generation of rheumatoid factor following continuous presentation of antigen-immunoglobulin complexes to B cells. CGs are thought to be responsible for a variety of extrahepatic manifestations associated with HCV, including vasculitis, glomerulonephritis, arthritis, and neuropathies, which occur in approximately 10% of HCV patients with CGs. CGs also are a powerful predictive factor for progressive liver disease and the aggressive reoccurrence of liver disease in HCV-positive patients after liver transplantation. First-line therapy for MC due to HCV infection is antiviral therapy with pegylated interferon-alpha and ribavirin. Viral eradication usually produces marked reduction of physical complications and arrests end organ damage concomitant with clearance of CG. Additional prospective, controlled studies are necessary to determine whether CG influences patient virologic response and/or its durability to antiviral therapy. Immunomodulators such as corticosteroids and cyclophosphamide are efficacious for palliative treatment of the symptomatology of HCV cryoglobulinemia but may enhance viral replication. Consequently, prolonged therapy with immunomodulatory agents should be limited to severe vasculitis or aggressive glomerulonephritis in patients with MC due to HCV who have failed to respond to antiviral therapy. In acute, fulminant presentations, plasmapheresis may provide temporary relief and arrest the rapid progression of the disease so that additional therapy can be initiated.

Novel Therapies for Hepatitis C: Insights from the Structure of the Virus

For the first time since the discovery of the hepatitis C virus (HCV), therapeutic options for hepatitis C have expanded. Several agents directly effective against HCV are now in development, including both direct-acting antiviral agents (DAAs) and host cofactor inhibitors. DAAs have been developed to inhibit several HCV proteins, including the NS3/4A serine protease, the NS5B RNA polymerase, NS5A, and NS4B. Host cofactor inhibitors include, but are not limited to, cyclophilin inhibitors, miR122 antagonists, and statins. Development of these agents represents a major advance in HCV therapeutics. This review provides a guide to HCV drugs in various stages of development, including an introduction to their mechanism of action, state of clinical development, efficacy, and side effects.

Controlled release recombinant human interferon-α2b for treating patients with chronic hepatitis C genotype 1: a phase 2a clinical trial

Better convenience and tolerability and sustained therapeutic concentrations might improve interferon (IFN) treatment for chronic hepatitis C virus (HCV) infection. In an open-label, randomized study, controlled release free (chemically unmodified) recombinant human IFN-α(2b) in poly(ether-ester) microspheres (CR-rhIFN-α(2b)), was injected at doses of 160, 320, 480 or 640 μg every 2 weeks for 12 weeks with concomitant weight-based oral ribavirin in 32 treatment-naïve patients with chronic HCV genotype 1. Treatment was well tolerated, with 31 patients (97%) successfully completing the study. Full doses of CR-rhIFN-α(2b) were administered on 96% of scheduled occasions. Flu-like symptoms were generally mild and brief. Injection site reactions developed in 13 patients (41%), and neutropenia occurred in six of eight patients receiving 640 μg. In the 320, 480 and 640 μg groups, 62-75% of patients achieved a ≥2 log(10) HCV RNA reduction by 4 weeks and 88-100% by 12 weeks. For those groups, the pooled median time to ≥2 log(10) reduction was 11 days (95% confidence interval, 7-35 days). In those groups, viral reduction below the limit of detection was accomplished in 25% of patients by 4 weeks and in 62% by 12 weeks. The 160-μg dose was less potent. After CR-rhIFN-α(2b) injection, stable plateau levels of serum IFN-α(2b) were generally reached within 72 h. Treatment-emergent neutralizing antibodies to IFN-α(2b) were observed in one patient. No antibodies to host plant proteins were detected. CR-rhIFN-α(2b) with ribavirin cotherapy was well tolerated and displayed potent early antiviral activity in patients with chronic HCV genotype 1.

Changes in hepatitis C viral load during first 14 days can predict the undetectable time point of serum viral load by pegylated interferon and ribavirin therapy

AIM

  In the treatment of chronic hepatitis C, pegylated interferon (PEG-IFN) and ribavirin combination therapy must be continued for an adequate duration to improve the rate of sustained virological response. We attempted to predict the time point at which serum hepatitis C virus (HCV) RNA are undetectable during combination therapy.

METHODS

  Patients with HCV genotype 1b were enrolled in a model preparation (n = 35) and a validation group (n = 70). All patients received PEG-IFN-α-2b/ribavirin combination therapy for at least 48 weeks, and serological samples were screened a minimum of 17 times during the therapy. Serum HCV RNA were measured by the Abbott RealTime HCV assay. Using the HCV dynamics model described by Neumann et al., we used multiple linear regression analysis to select factors that affected the undetectable time point.

RESULTS

  Difference in viral load between weeks 1 and 2 was the only predictive factor for the undetectable time point of serum HCV RNA (r(2)  = 0.67, P < 0.0005), and we derived the following prediction equation: undetectable time point (week) = 13.495 × (viral load at day 14 [log IU/mL] - viral load at day 7 [log IU/mL]) + 25.456. The equation was applicable to the validation group.

CONCLUSION

  We created a formula for predicting the undetectable time point from viral load measurements early in PEG-IFN-α-2b/ribavirin combination therapy. An early response reflects sensitivity to therapy, and the estimation of an undetectable time point would be useful for determining the optimal duration of treatment for chronic hepatitis C patients.

Ribavirin-induced anemia in hepatitis C virus patients undergoing combination therapy

The current standard of care for hepatitis C virus (HCV) infection – combination therapy with pegylated interferon and ribavirin – elicits sustained responses in only ∼50% of the patients treated. No alternatives exist for patients who do not respond to combination therapy. Addition of ribavirin substantially improves response rates to interferon and lowers relapse rates following the cessation of therapy, suggesting that increasing ribavirin exposure may further improve treatment response. A key limitation, however, is the toxic side-effect of ribavirin, hemolytic anemia, which often necessitates a reduction of ribavirin dosage and compromises treatment response. Maximizing treatment response thus requires striking a balance between the antiviral and hemolytic activities of ribavirin. Current models of viral kinetics describe the enhancement of treatment response due to ribavirin. Ribavirin-induced anemia, however, remains poorly understood and precludes rational optimization of combination therapy. Here, we develop a new mathematical model of the population dynamics of erythrocytes that quantitatively describes ribavirin-induced anemia in HCV patients. Based on the assumption that ribavirin accumulation decreases erythrocyte lifespan in a dose-dependent manner, model predictions capture several independent experimental observations of the accumulation of ribavirin in erythrocytes and the resulting decline of hemoglobin in HCV patients undergoing combination therapy, estimate the reduced erythrocyte lifespan during therapy, and describe inter-patient variations in the severity of ribavirin-induced anemia. Further, model predictions estimate the threshold ribavirin exposure beyond which anemia becomes intolerable and suggest guidelines for the usage of growth hormones, such as erythropoietin, that stimulate erythrocyte production and avert the reduction of ribavirin dosage, thereby improving treatment response. Our model thus facilitates, in conjunction with models of viral kinetics, the rational identification of treatment protocols that maximize treatment response while curtailing side effects.

The treatment of HCV infection poses a major global health-care challenge today. The current standard of care, combination therapy with interferon and ribavirin, works in only about half of the patients treated. Because no alternatives are available yet for patients in whom combination therapy fails, identifying ways to improve response to combination therapy is critical. Increasing exposure to ribavirin does improve response but is associated with the severe side-effect, anemia. One way to maximize treatment response therefore is to increase ribavirin exposure to levels just below where anemia becomes intolerable. A second way is to supplement combination therapy with growth hormones, such as erythropoietin, that increase the production of red blood cells (erythrocytes) and compensate for ribavirin-induced anemia. Rational optimization of combination therapy thus relies on a quantitative description of ribavirin-induced anemia, which is currently lacking. Here, we develop a model of the population dynamics of erythrocytes in individuals exposed to ribavirin that quantitatively describes ribavirin-induced anemia. Model predictions capture several independent observations of ribavirin-induced anemia in HCV patients undergoing combination therapy, estimate the threshold ribavirin exposure beyond which anemia becomes intolerable, suggest guidelines for the usage of growth hormones, and facilitate rational optimization of therapy.

Relationship between the hepatitis C viral load and the serum interferon concentration during the first week of peginterferon-alpha-2b-ribavirin combination therapy

In chronic hepatitis C virus (HCV) infections, the current standard of care (combination therapy with pegylated alpha interferon (PEG-IFNalpha) and ribavirin) is only effective in around 50% of cases. The aim of the present study was to analyze the relationship between the HCV load and the PEG-IFN concentration during the first week of treatment. Fifteen treatment-naive patients with chronic hepatitis C infection (genotypes 1, 2, 3, and 4) underwent PEG-IFNα-2b/ribavirin combination therapy. Blood samples were collected before the first injection (T(0)) and then at different time points until the next injection a week later. The PEG-IFN concentration and the HCV load were assayed. The serum interferon concentration peaked 2 days after the first injection (mean value for the study population; T(max) = 40.9 hr; C(max) = 490 pg/ml) and a trough in viral load was seen at day 3. The PEG-IFNalpha-2b concentration decreased from day 2 to day 7, enabling a viral rebound in all patients. The change in viral load between day 0 and day 3 differed significantly according to whether the patients were responders at week 12 (Deltalog d(0)/d(3) = 2.729 +/- 1.419 log(10) IU/ml) or not (Deltalog d(0)/d(3) = 1.102 +/- 0.472 log(10) IU/ml). Our results emphasize the potential clinical importance of achieving viral decay immediately after initiation of interferon-ribavirin combination therapy. J. Med. Virol. 82:1640-1646, 2010. 2010 Wiley-Liss, Inc.

Plasma/erythrocyte ribavirin x100 ratio as an indicator of sustained virological response in HCV genotype 1 patients with early virological response

BACKGROUND

On-treatment predictors during antiviral therapy of HCV are useful because they allow discontinuation of an unnecessary treatment in non-responders. Our aim was to evaluate the usefulness of plasma and erythrocyte ribavirin levels in predicting sustained virological response (SVR) in HCV genotype 1 patients undergoing antiviral treatment.

METHODS

A total of 40 HCV genotype 1 patients treated with pegylated interferon-alpha2a 180 microg weekly plus ribavirin 1,000 or 1,200 mg daily (according to body weight) were included in the study. Plasma and erythrocyte ribavirin levels were evaluated in all patients at week 12 by HPLC. At week 24, ribavirin levels were reassessed in those achieving early virological response (EVR).

RESULTS

A total of 27 patients achieved EVR, whereas 17 achieved SVR. There was no difference among EVR and non-EVR patients in terms of plasma and erythrocyte ribavirin concentrations at week 12. At week 24, EVR patients obtaining SVR exhibited higher mean +/-sd levels of ribavirin in plasma and lower levels in erythrocytes compared with non-SVR patients (in plasma 12.8 +/-10 versus 5.8 +/-4 microM [P<0.02] and in erythrocytes 1,053 +/-504 versus 1,613 +/-589 microM [P<0.03]). When the plasma ribavirin/erythrocyte ribavirin x100 ratio was compared, the difference was enhanced (1.5 +/-1.3 versus 0.4 +/-0.3 microM; P<0.01). Receiver operating characteristic curve analysis identified a cutoff for plasma ribavirin/erythrocyte ribavirin x100 ratio in predicting SVR of 0.71 with a negative predictive value of 0.8 and a positive predictive value of 0.9, whereas those related to EVR were 1 and 0.6, respectively.

CONCLUSIONS

Plasma ribavirin/erythrocyte ribavirin x100 ratio at week 24 seems to be a good indicator of SVR in HCV genotype 1 patients achieving EVR.

Diagnosis and management of interstitial pneumonitis associated with interferon therapy for chronic hepatitis C

Interstitial pneumonitis (IP) is an uncommon pulmonary complication associated with interferon (IFN) therapy for chronic hepatitis C virus (HCV) infection. Pneumonitis can occur at any stage of HCV treatment, ranging from 2 to 48 wk, usually in the first 12 wk. Its most common symptoms are dyspnoea, dry cough, fever, fatigue, arthralgia or myalgia, and anorexia, which are reversible in most cases after cessation of IFN therapy with a mean subsequent recovery time of 7.5 wk. Bronchoalveolar lavage in combination with chest high resolution computed tomography has a high diagnostic value. Prompt discontinuation of medication is the cornerstone, and corticosteroid therapy may not be essential for patients with mild-moderate pulmonary functional impairment. The severity of pulmonary injury is associated with the rapid development of IP. We suggest that methylprednisolone pulse therapy followed by low dose prednisolone for a short term is necessary to minimize the risk of fatal pulmonary damage if signs of significant pulmonary toxicity occur in earlier stage. Clinicians should be aware of the potential pulmonary complication related to the drug, so that an early and opportune diagnosis can be made.

Pharmacokinetics and pharmacodynamics of peginterferon and ribavirin: implications for clinical efficacy in the treatment of chronic hepatitis C

The pharmacokinetics and pharmacodynamics of standard interferon alfa-2a and interferon alfa-2b are substantially altered by pegylation. The size, geometry, and site of attachment of the PEG moiety affect the pharmacokinetics and pharmacodynamics as evidenced by the different absorption, volume of distribution, and clearance of the linear 12-kDa peginterferon alfa-2b and the branched 40-kDa peginterferon alfa-2a. Despite these differences, the clinical efficacy, safety, and tolerability of the 2 peginterferons are similar. However, evidence exists that peginterferon alfa-2 plus ribavirin is associated with small but significantly higher sustained virological response rates compared with peginterferon alfa-2b. This article discusses the pharmacokinetics and pharmacodynamics of the 2 peginterferons and their combination with ribavirin.

Quantitative determination of pegylated consensus interferon in rhesus monkey serum using a competitive enzyme-linked immunosorbent assay

A competitive enzyme-linked immunosorbent assay (ELISA) with generated mouse anti-consensus interferon (CIFN) antibody was developed for quantitative determination of pegylated consensus interferon (PEG-CIFN) in rhesus monkey serum. The operational concentrations of the original assay were determined using the chessboard method. ELISA working range was 10-5000 ng/ml, corresponding to a limit of quantification of 8.4 ng/ml in rhesus monkey serum. In a precision test, intra-assay CV ranged 1.8-9.6% and inter-assay CV ranged 3.5-12.7%. Relative recovery rate of this ELISA assay ranged from 102.65-115.77%, with RSD values ranging from 2.26-5.44%. Three groups of rhesus monkeys received 1250 microg/kg, 300 microg/kg, 150 microg/kg PEG-CIFN by subcutaneous administration, and blood samples were drawn via the femoral vein at the specified time points. PEG-CIFN in rhesus monkey serum was determined using the competitive ELISA, and the results were compared with antiviral activity assay. In conclusion, the competitive ELISA assay we developed has sufficient sensitivity, precision, and accuracy for the analysis of a rhesus monkey serum sample.

Metastatic renal cell carcinoma treated with Peg-interferon alfa-2b

INTRODUCTION

Peginterferon has an increased plasma half-life and enables a constant exposure to interferon. This modification might increase the antiangiogenic effect of the treatment and influence the efficacy. We report the results of a phase II open-label study with Peginterferon alfa-2b (Pegintron Schering-Plough) on efficacy and tolerability in patients with advanced renal cell carcinoma (MRCC).

MATERIALS AND METHODS

Twenty eight patients with MRCC were treated with Peginterferon in escalating doses of 0.5 microg/kg once weekly until 2 microg/kg was reached or prohibited toxicity occurred. Lesions were evaluated according to Response Evaluation Criteria in Solid Tumors (RECIST).

RESULTS

Thirteen patients tolerated a dose of 2 microg/kg/week. At 6 months 16 patients (57%) had disease control of which four had partial response (PR) and 12 stable disease whereas 12 (43%) had progressed. PR was only seen in the lung parenchyma or mediastinum. Median time to progression (TTP) was 8 months in all patients and 13 months for PR and SD patients. Correspondingly, median survival was 19.5 months and 28 months, respectively (seven patients received second-line treatment with tyrosine kinase inhibitor). The mean dose during long-term treatment was 1.5 and at the end of treatment 1.2 microg/kg/week. Most side effects were grade 1-2 and only two patients stopped treatment for that reason. VEGF levels in serum before and during treatment did not correlate to the therapeutic response.

DISCUSSION

Peginterferon was well tolerated in MRCC albeit with dose modification during long-term treatment. Response pattern seems to be the same as with nonpegylated interferon. Peginterferon may be used as monotherapy in selected patients and in trials of combinations with targeted drugs.

Ribavirin plus interferon versus interferon for chronic hepatitis C

BACKGROUND

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.

OBJECTIVES

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

SEARCH STRATEGY

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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.

MAIN RESULTS

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.

AUTHORS' CONCLUSIONS

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.

Ribavirin monotherapy for chronic hepatitis C

BACKGROUND

Hepatitis C is a major cause of liver-related morbidity and mortality. A high proportion of patients never experience symptoms. Peginterferon plus ribavirin is the recommended treatment for chronic hepatitis C. However, ribavirin monotherapy may be considered for some patients.

OBJECTIVES

To assess the beneficial and harmful effects of ribavirin monotherapy for patients with chronic hepatitis C.

SEARCH STRATEGY

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

SELECTION CRITERIA

We included all randomised trials irrespective of blinding, language, or publication status comparing ribavirin versus no intervention, placebo, or interferon for chronic hepatitis C.

DATA COLLECTION AND ANALYSIS

The primary outcome measures were serum sustained virological response (loss of hepatitis C virus RNA at least six months after treatment), liver-related morbidity plus all-cause mortality, and adverse events. Secondary outcome measures were end of treatment virological response, biochemical response (transaminase activity), and histological response. Randomisation methods, blinding, data handling, and funding were extracted as measures of bias control. Random-effects and fixed-effect meta-analyses were performed for all outcomes. We only present the results of the fixed-effect model if both models provide the same result regarding statistical significance. We present data as risk difference (RD) with 95% confidence intervals (CI).

MAIN RESULTS

We included 14 randomised trials with 657 patients. The majority of trials had unclear control of bias. Compared with placebo or no intervention, ribavirin had no significant effect on the sustained virological response (RD 0%, 95% CI -2% to 3%, five trials) or end of treatment virological response (RD 0% 95% CI -3% to 3%, ten trials). Ribavirin had no significant effect on liver-related morbidity plus mortality (RD 0%, 95% CI -2% to 3%, 11 trials). Ribavirin significantly increased the risk of adverse reactions, including anaemia. Ribavirin significantly improved end of treatment biochemical and histological response but not the sustained biochemical response. Ribavirin was significantly inferior to interferon regarding virological and biochemical responses (five trials).

AUTHORS' CONCLUSIONS

Ribavirin seems without beneficial effects on serum virological response and liver-related morbidity or mortality, and significantly increased the risk of adverse reactions. Ribavirin monotherapy seems significantly inferior to interferon monotherapy. The total number of included patients is small, and more trials are perhaps needed. The use of ribavirin monotherapy for chronic hepatitis C cannot be recommended outside randomised trials.

Stable replication of the EBNA1/OriP-mediated baculovirus vector and its application to anti-HCV gene therapy

Background

Hepatitis C virus (HCV) is one of the main causes of liver-related morbidity and mortality. Although combined interferon-α-ribavirin therapy is effective for about 50% of the patients with HCV, better therapies are needed and preventative vaccines have yet to be developed. Short-hairpin RNAs (shRNAs) inhibit gene expression by RNA interference. The application of transient shRNA expression is limited, however, due to the inability of the shRNA to replicate in mammalian cells and its inefficient transduction. The duration of transgene (shRNA) expression in mammalian cells can be significantly extended using baculovirus-based shRNA-expressing vectors that contain the latent viral protein Epstein-Barr nuclear antigen 1 (EBNA1) and the origin of latent viral DNA replication (OriP) sequences. These recombinant vectors contain compatible promoters and are highly effective for infecting primary hepatocyte and hepatoma cell lines, making them very useful tools for studies of hepatitis B and hepatitis C viruses. Here, we report the use of these baculovirus-based vector-derived shRNAs to inhibit core-protein expression in full-length hepatitis C virus (HCV) replicon cells.

Results

We constructed a long-term transgene shRNA expression vector that contains the EBV EBNA1 and OriP sequences. We also designed baculovirus vector-mediated shRNAs against the highly conserved core-protein region of HCV. HCV core protein expression was inhibited by the EBNA1/OriP baculovirus vector for at least 14 days, which was considerably longer than the 3 days of inhibition produced by the wild-type baculovirus vector.

Conclusion

These findings indicate that we successfully constructed a long-term transgene (shRNA) expression vector (Ac-EP-shRNA452) using the EBNA1/OriP system, which was propagated in Escherichia coli and converted into mammalian cells. The potential anti-HCV activity of the long-term transgene (shRNA) expression vector was evaluated with the view of establishing highly effective therapeutic agents that can be further developed for HCV gene therapy applications.

Assessment of the efficacy of reducing peginterferon alpha-2a and ribavirin dose on virologic response in Koreans with chronic hepatitis C

BACKGROUND/AIMS

The virologic response of Koreans to combination therapy for chronic hepatitis C is similar to westerns; however, dose modification occurs more frequently in Koreans. We evaluated the rates of peginterferon alpha-2a and ribavirin dose modifications and their effect on the virologic response in Koreans.

METHODS

Patients with detectable HCV RNA and enrolled from multicenters were treated with peginterferon alpha-2a (180 microg/week) and ribavirin (800 mg/day) for 24 weeks (genotype non-1, n=37) or peginterferon alpha-2a (180 microg/week) and ribavirin (1,000-1,200 mg/day) for 48 weeks (genotype 1, n=55).

RESULTS

Early virologic response (EVR) and sustained virologic response (SVR) were 77.2% (genotype 1, 75%; non-1, 81%) and 66.3% (genotype 1, 56%; non-1, 81%), respectively. The frequency of dose modification was 32.6% within the first 12 weeks and 52.2% during the entire treatment period. No difference was found in SVR regardless of dose modification. However, the SVR for patients using >or=80% of the peginterferon dose was significantly higher than for those using <80% (81.3 vs. 50.0%, p=0.007), despite varying ribavirin doses. No difference was found in SVR regardless of whether the ribavirin dose was <80% or not. These results did not change based on genotype.

CONCLUSIONS

We suggest that using at least 80% of the peginterferon alpha-2a dose in Koreans not only maintains SVR but also reduces drug side effects during the entire treatment period. A lower dose of ribavirin may be as efficacious as a standard dose.

Long-term pegylated interferon-alpha and its potential in the treatment of melanoma

Conventional interferons including interferon-alpha (IFN-alpha) are cytokines used for years in the treatment of solid tumors and hematological malignancies. Their half-life is short. Pegylated forms of IFN-alpha present an improved pharmacokinetic profile that rendered them the preferred IFNs in hepatitis therapy. In the last decade, pegylated interferons (PegIFNs) have been investigated in melanoma patients. We review the scientific published literature on biology, pharmacokinetics, side effects and clinical applications of PegIFN-alpha in the treatment of stage III and IV melanoma. In the adjuvant setting, PegIFNalpha-2b has significant prolonged distant metastases free survival in patients with microscopic nodal involvement (stage TxN1aM0) and therefore is a promising treatment option in this patient population. In the palliative setting, monotherapy with PegIFNalpha-2alpha can induce complete remissions in a minority of stage IV melanoma patients. The combination of monochemotherapy is feasible and may result in lasting complete remissions. Ongoing research must focus on the identification of patients who mostly benefit, so that unnecessary toxicity would be avoided. Combining PegIFNs and chemotherapy or targeted agents deserves further exploration.

Peginterferon alfa-2a relapse rates depend on weight-based ribavirin dosage in HCV-infected patients with genotype 1: results of a retrospective evaluation

OBJECTIVE

The cumulative dosage of ribavirin per kilogram of body-weight prevents relapse and thus is a significant predictor of sustained virological response (SVR). Comparison of peginterferon (peg-IFN) alfa-2b/ribavirin and peg-IFN alfa-2a/ribavirin shows that the rates of SVR are similar, but the rates of relapse are significantly lower under the peg-IFN alfa-2b regimen. Depending on the weight-based ribavirin dose, patients with >105 kg reach a maximum of 13.2 mg/kg body-weight ribavirin in the peg-IFN alfa-2b regimen as opposed to only 11.3 mg/kg in the peg-IFN alfa-2a regimen. The aim of these investigations was to determine relapse rates in a retrospective analysis of 98 patients chronically infected with hepatitis C virus (HCV) genotype (GT) 1 in relation to the weight-based ribavirin dose.

MATERIAL AND METHODS

All patients completed treatment with peg-IFN alfa-2a/ribavirin (1000 mg/d or 1200 mg/d for patients weighing <75 kg or > or =75 kg) for 48 weeks. Classification of a low ribavirin dose with <13.2 mg/kg body-weight was used. Patients with a ribavirin dose > or =13.2 mg/kg were compared with those with a dose <13.2 mg/kg.

RESULTS

Patients with a ribavirin dose > or = 13.2 mg/kg (n=84) showed a relapse rate of 19.0% in contrast to 71.4% in patients with a ribavirin dose of <13.2 mg/kg (n=14) (p=0.0013). The SVR rate was significantly higher in the > or =13.2 mg/kg ribavirin dosed group (59.5% versus 28.6%).

CONCLUSIONS

Weight-adapted ribavirin dosing in combination with peg-IFN alfa-2a to avoid giving low doses of ribavirin should be evaluated. This will minimize relapse, especially in HCV GT 1 patients.

Impact of early viral kinetics on pegylated interferon alpha 2b plus ribavirin therapy in Japanese patients with genotype 2 chronic hepatitis C

The recommended therapy for genotype-2 chronic hepatitis C is a regimen of pegylated interferon alpha (peginterferon) plus ribavirin. This study was conducted to determine the value of early viral kinetics as a predictive factor for sustained virologic responder (SVR). Peginterferon alpha 2b (1.5 microg/kg/week) plus weight-based ribavirin (600-1000 mg/day) was administered to 51 patients with chronic HCV genotype 2 for 24 weeks. The HCV-RNA loads were measured at the baseline, hour 24, and week 1. The rebound index (RI, an index obtained from the viral load of week 1 divided by that of hour 24) was calculated. Compared with the baseline, the viral load at hour 24 for SVR was reduced by more than 1-log: it continued to decline thereafter, and at week 1 it was significantly lower than at hour 24 (P < 0.05). The viral load for non-SVR increased again between hour 24 and week 1. The SVR of patients with RI <or=1.0 was 100% (39/39). The SVR conversion for rapid virologic responders was 92% (35/38). The RI (<or=1.0) was the only significant independent factor for SVR by multiple logistic regression analysis and is the first predictive factor in 24-week peginterferon plus ribavirin therapy for patients infected with genotype 2.

Low weight predicts neutropenia and peginterferon alfa-2a dose reductions during treatment for chronic hepatitis C

Treatment-induced neutropenia frequently complicates the treatment course of patients treated with pegylated interferon alfa and ribavirin for chronic hepatitis C. We investigated the effect of weight on the risk for dose reductions caused by neutropenia in patients treated with a weight-independent dose of peginterferon alfa-2a. We retrospectively analysed single centre data for 172 patients enrolled in a multi-centre, open-label trial of peginterferon alfa-2a and ribavirin for chronic hepatitis C. Low body weight was significantly associated with dose reductions due to neutropenia. Patients weighing less than 62 kg had a 35% risk for significant neutropenia as opposed to a 12% risk for heavier patients (P = 0.001), and this side-effect occurred earlier during treatment. Low weight was an independent risk factor by multivariate analysis (hazard ratio 0.956/kg). The risk for treatment-induced neutropenia was associated with body surface area more than with the body mass index. In conclusion, a low pre-treatment weight strongly predicts the need for peginterferon alfa-2a dose reductions. This apparently reflects overall body size more than body fat content. It is prudent to frequently monitor blood counts for smaller-sized patients, especially during the first weeks of treatment.

Heat-shock protein 90 is essential for stabilization of the hepatitis C virus nonstructural protein NS3

The hepatitis C virus (HCV) is a major cause of chronic liver disease. Here, we report a new and effective strategy for inhibiting HCV replication using 17-allylaminogeldanamycin (17-AAG), an inhibitor of heat-shock protein 90 (Hsp90). Hsp90 is a molecular chaperone with a key role in stabilizing the conformation of many oncogenic signaling proteins. We examined the inhibitory effects of 17-AAG on HCV replication in an HCV replicon cell culture system. In HCV replicon cells treated with 17-AAG, we found that HCV RNA replication was suppressed in a dose-dependent manner, and interestingly, the only HCV protein degraded in these cells was NS3 (nonstructural protein 3). Immunoprecipitation experiments showed that NS3 directly interacted with Hsp90, as did proteins expressed from DeltaNS3 protease expression vectors. These results suggest that the suppression of HCV RNA replication is due to the destabilization of NS3 in disruption of the Hsp90 chaperone complex by 17-AAG.

Dose comparison study of pegylated interferon-alpha-2b plus ribavirin in naïve Japanese patients with hepatitis C virus genotype 2: a randomized clinical trial

BACKGROUND AND AIM

To compare the efficacy and safety of pegylated interferon (PEG-I) at 1 and 1.5 microg/kg, and in combination with ribavirin (RBV) for 24 weeks in naïve Japanese patients infected with hepatitis C virus genotype 2.

METHODS

The present study was an open-label, randomized trial of 55 patients receiving PEG-I (1 or 1.5 microg/kg body weight [BW], subcutaneously, once a week) and RBV for 24 weeks. The patients were followed up for 24 weeks without treatment.

RESULTS

The intention-to-treat analyses showed that the proportion of patients with a sustained virological response (SVR) in the 1-microg/kg PEG-I-RBV group (38.5%, 10/26) was lower than that of the 1.5-microg/kg PEG-I-RBV group (74.1%, 20/27; P = 0.013). The PEG-I dose was reduced in two of the 26 patients of the 1-microg/kg PEG-I-RBV group (one because of thrombocytopenia at 2 weeks, and one because of generalized fatigue at 20 weeks), and four of the 27 patients of the 1.5-microg/kg PEG-I-RBV group (one because of neutropenia at 20 weeks, and three because of generalized fatigue at 1, 5, and 8 weeks). The multivariate analysis identified age (< 60 years) and dose of PEG-I (1.5 microg/kg) as significant determinants of SVR.

CONCLUSION

The dose of PEG-I to be used at the start of therapy should be 1.5-microg/kg BW in naïve Japanese patients infected with hepatitis C virus genotype 2.

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.

Suppression of hepatitis C virus replication by baculovirus vector-mediated short-hairpin RNA expression

Short-hairpin RNAs (shRNAs) inhibit gene expression by RNA interference. Here, we report on the inhibition, by baculovirus-based vector-derived shRNAs, of core-protein expression in full-length hepatitis C virus (HCV) replicon cells. shRNAs were designed to target the highly conserved core region of the HCV genome. In particular, the core-shRNA452 containing nucleotides 452-472, as the target in the HCV core gene, dramatically inhibited the expression of the HCV core protein in replicon cells. Furthermore, HCV core-protein expression was inhibited more strongly by the vesicular stomatitis virus glycoprotein (VSV-G)-pseudotyped baculovirus vector than by the wild-type baculovirus vector.