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

The role of cytokines in shaping the future of Cancer immunotherapy

As essential immune system regulators, cytokines are essential for modulating both innate and adaptive immunological responses. They have become important tools in cancer immunotherapy, improving the immune system's capacity to identify and destroy tumor cells. This article examines the background, workings, and therapeutic uses of cytokines, such as interleukins, interferons, and granulocyte-macropHage colony-stimulating factors, in the management of cancer. It examines the many ways that cytokines affect immune cell activation, signaling pathways, tumor development, metastasis, and prognosis by modifying the tumor microenvironment. Despite the limited effectiveness of cytokine-based monotherapy, recent developments have concentrated on new fusion molecules such as immunocytokines, cytokine delivery improvements, and combination techniques to maximize treatment efficacy while reducing adverse effects. Current FDA-approved cytokine therapeutics and clinical trial results are also included in this study, which offers insights into how cytokines might be used with other therapies including checkpoint inhibitors, chemotherapy, and radiation therapy to address cancer treatment obstacles. This study addresses the intricacies of cytokine interactions in the tumor microenvironment, highlighting the possibility for innovative treatment methods and suggesting fresh techniques for enhancing cytokine-based immunotherapies. PEGylation, viral vector-mediated cytokine gene transfer, antibody-cytokine fusion proteins (immunocytokines), and other innovative cytokine delivery techniques are among the novelties of this work, which focuses on the most recent developments in cytokine-based immunotherapy. Additionally, the study offers a thorough examination of the little-reviewed topic of cytokine usage in conjunction with other treatment techniques. It also discusses the most recent clinical studies and FDA-approved therapies, providing a modern perspective on the developing field of cancer immunotherapy and suggesting creative ways to improve treatment effectiveness while lowering toxicity. BACKGROUND: Cytokines are crucial in cancer immunotherapy for regulating immune responses and modifying the tumor microenvironment (TME). However, challenges with efficacy and safety have driven research into advanced delivery methods and combination therapies to enhance their therapeutic potential.

Engineering a New IFN-ApoA-I Fusion Protein with Low Toxicity and Prolonged Action

Recombinant human interferon alpha-2b (rIFN) is widely used in antiviral and anticancer immunotherapy. However, the high efficiency of interferon therapy is accompanied by a number of side effects; this problem requires the design of a new class of interferon molecules with reduced cytotoxicity. In this work, IFN was modified via genetic engineering methods by merging it with the blood plasma protein apolipoprotein A-I in order to reduce acute toxicity and improve the pharmacokinetics of IFN. The chimeric protein was obtained via biosynthesis in the yeast P. pastoris. The yield of ryIFN-ApoA-I protein when cultivated on a shaker in flasks was 30 mg/L; protein purification was carried out using reverse-phase chromatography to a purity of 95-97%. The chimeric protein demonstrated complete preservation of the biological activity of IFN in the model of vesicular stomatitis virus and SARS-CoV-2. In addition, the chimeric form had reduced cytotoxicity towards Vero cells and increased cell viability under viral load conditions compared with commercial IFN-a2b preparations. Analysis of the pharmacokinetic profile of ryIFN-ApoA-I after a single subcutaneous injection in mice showed a 1.8-fold increased half-life of the chimeric protein compared with ryIFN.

Pharmacokinetics and Pharmacodynamics of Ropeginterferon Alfa-2b in Healthy Japanese and Caucasian Subjects After Single Subcutaneous Administration

BACKGROUND AND OBJECTIVES

Ropeginterferon alfa-2b is a novel monopegylated recombinant interferon alfa-2b for the treatment of patients with polycythemia vera. The objectives of this study were to evaluate the pharmacokinetics, pharmacodynamics, safety, and tolerability of ropeginterferon alfa-2b in healthy Japanese subjects compared with Caucasian subjects.

METHODS

In this multicenter, parallel-group phase I study, a cohort consisting of six Japanese and six Caucasian subjects was designated to receive a single subcutaneous dose of ropeginterferon alfa-2b (100, 200, 300, and 450 µg). Pharmacokinetic and pharmacodynamic parameters, and immunogenicity were evaluated. Safety was assessed throughout the study.

RESULTS

Cohort 4 (450-µg dose) was not initiated because the primary objective of this study was achieved based on the three completed cohorts. A total of 36 enrolled subjects (18 Japanese and 18 Caucasian) in three cohorts were included in the safety, pharmacokinetic, and pharmacodynamic analysis sets. Ropeginterferon alfa-2b exposure in terms of the area under the serum concentration-time curve (AUC) from time zero extrapolated to infinity and the AUC from time zero to the time of the last quantifiable concentration was approximately 1.7-fold and two-fold higher in Japanese subjects than in Caucasian subjects, respectively. Across the same dose range, the maximum serum concentration was approximately 1.25-fold higher in Japanese subjects than in Caucasian subjects. The time to reach the median maximum serum concentration was similar between ethnicities (approximately 96-111 h). The terminal half-life was 48-57 h in Japanese subjects and 31-75 h in Caucasian subjects. The slope of the relationship between dose and drug exposure was greater than 1 in both ethnicities. The dose-dependent induction of beta-2 microglobulin and neopterin expression was observed in both ethnicities, and the two groups showed similar pharmacodynamic parameters. At the end of the study, 22.2% of Japanese subjects and 11.1% of Caucasian subjects developed anti-ropeginterferon alfa-2b-binding antibodies. The neutralizing capacity of these antibodies was not tested. Ropeginterferon alfa-2b up to 300 µg was safe and well tolerated, with no unexpected safety findings based on previous experiences with ropeginterferon alfa-2b and other forms of interferon.

CONCLUSIONS

Ropeginterferon alfa-2b exposure was higher in Japanese subjects than in Caucasian subjects. The increase in ropeginterferon alfa-2b exposure was greater than the dose proportion in the dose range of 100-300 µg. Ropeginterferon alfa-2b was safe and well tolerated.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT03546465, registered on 6 June, 2018.

Pharmacotherapy options for managing hepatitis B in children

INTRODUCTION

To eliminate viral hepatitis by 2030, the World Health Organization (WHO) launched the first global health sector strategy on viral hepatitis, with particular focus given to hepatitis B and C in 2016. To achieve the reduction of mortality in children, it is indispensable to know which children should be treated and how to treat them.

AREA COVERED

In this article, the authors review the antiviral treatment of children with chronic hepatitis B virus (HBV) infection including antivirals available for children with chronic HBV infection.

EXPERT OPINION

The approvals of nucleos(t)ide analogues (NAs) and pegylated interferon (PEG-IFN) for children have lowered a hurdle to the initiation of antiviral treatment in children. The international guidelines use nearly the same criteria of antiviral treatment for children with chronic HBV infection, but the WHO guidelines provide a cautious stance on the antiviral treatment of children. Not only PEG-IFN but also NAs with a high genetic barrier to drug resistance should be the first-line treatment for children. In settings with limited medical resources, NAs can be the first-line treatment for children. Although the concept of an 'immune-tolerant phase' is challenged, evidence is not sufficient to recommend the treatment of HBeAg-positive immune-tolerant children.

Peginterferon alfa-2a for the treatment of chronic hepatitis C in the era of direct-acting antivirals

BACKGROUND

The availability of novel direct-acting antivirals (DAAs) represents a new era of curative hepatitis C virus (HCV) treatment, with over 95% of patients infected with HCV genotype 1 achieving sustained virological response (SVR). Nevertheless, the majority of patients globally are unable to access these treatments because of cost and infrastructure constraints and, thus, remain untreated and uncured.

DATA SOURCE

Relevant articles of peginterferon (PegIFN)-based treatments in HCV and sofosbuvir-based treatments, simeprevir, daclatasvir/asunaprevir, ritonavir-boosted paritaprevir/ombitasvir/dasabuvir, and grazoprevir/elbasvir, were searched in PubMed database, including general population and special population.

RESULTS

PegIFN in combination with ribavirin remains an important and relevant option for some patients, achieving SVR rates of up to 79% in genotype 1 and 89% in genotype 2 or 3 infections, which increases for patients with favorable IL28B genotypes. Triple therapy of DAA plus PegIFN/ribavirin is effective in treating difficult-to-cure patients infected with HCV genotype 3 or with resistance-associated variants. Owing to its long history in HCV management, the efficacy, tolerability and long-term outcomes associated with PegIFN alfa-2a are well established and have been validated in large-scale studies and in clinical practice for many populations. Furthermore, emerging data show that IFN-induced SVR is associated with lower incidences of hepatocellular carcinoma compared with DAAs. On the contrary, novel DAAs have yet to be studied in special populations, and long-term outcomes, particularly tumor development and recurrence in patients with cirrhosis and/or hepatocellular carcinoma, and reactivation of HBV in dually infected patients, are still unclear.

CONCLUSION

In this interferon-free era, PegIFN-based regimens remain a safe and effective option for selected HCV patients.

HM10660A, a long-acting hIFN-α-2b, is a potent candidate for the treatment of hepatitis C through an enhanced biological half-life

Interferon-α (IFN-α) has been widely used for the treatment of infections due to the hepatitis C virus (HCV). Because of the short half-life of IFN-α in serum, it must be administered three times per week. To increase the half-life of IFN-α, the immunoglobulin G4 (IgG4) Fc fragment (HMC001) was conjugated with human IFN-α-2b to develop a long-acting IFN-α-2b, HM10660A. An analysis of the antiviral efficacy of HM10660A in a human hepatocyte-engrafted mouse model found that HM10660A reduced serum HCV titers more effectively than a commercially available peginterferon α-2a (PEGASYS^®) and IFN-α-2b. Pharmacokinetic (PK) and pharmacodynamic (PD) studies of HM10660A using monkeys demonstrated that the half-life of HM10660A was approximately 2-fold longer than commercially available peginterferon α-2a, which is approved for a once-weekly regimen. Moreover, the IFN-mediated induction profiles of neopterin and 2', 5'-oligoadenylate synthase (OAS) in normal cynomolgus monkeys indicated that HM10660A had enhanced antiviral activity and a prolonged duration of action compared with peginterferon α-2a. Considering the improved PK and PD properties, HM10660A can most likely be dosed every two or four weeks, providing superior antiviral efficacy and convenience for patients with HCV.

Long-term effects of peginterferon alfa-2a therapy in Japanese patients with chronic hepatitis B virus infection

Background

There is no information on the long-term effects of peginterferon (PEG-IFN) alfa-2a therapy for chronic hepatitis B (CHB) in Japan. This double-blind, randomized trial investigated the efficacy of PEG-IFN therapy.

Methods

We analyzed 22 Japanese patients with CHB (hepatitis B e antigen [HBeAg]-positive: 17, HBeAg-negative: 5) treated with PEG-IFN alfa-2a and followed-up posttreatment for 5 years. Responders represented patients who showed persistent normalization of alanine transferase (ALT) levels, HBeAg clearance, and low hepatitis B virus (HBV) DNA levels (HBeAg-positive patient; <5 log copies/mL, HBeAg-negative patient; <4.3 log copies/mL) at end of treatment, and at 1, 2, 3, 4 and 5 years posttreatment. In addition, baseline HBeAg-positive patients who showed sustained normalization of ALT level, HBeAg clearance, and low HBV DNA level for more than 6 months until at 1, 2, 3, 4, and 5 years after completion of PEG-IFN were also classified as “triple responders” and the proportion of triple responders relative to all patients was termed the “triple response rate”.

Results

The response rates among HBeAg-positive patients were 13 %, 25 %, 14 %, 21 % and 21 % at end of treatment, and at 1, 2, 3, 4, and 5 years, respectively. The response rate tended to be higher in patients treated for 48 than 24 weeks. The respective response rates among HBeAg-negative patients were 0 %, 20 %, 20 %, 20 % and 25 %. During the treatment period, hepatitis B surface antigen (HBsAg) clearance at 3.5 years was noted in one patient, who was 37-year-old, male, had genotype C and received PEG-IFN alfa-2a at 90 μg for 48 weeks.

Conclusion

At 5 years after completion of PEG-IFN, the triple response rate in HBeAg-positive patients and combined response rate in HBeAg-negative patients were 21 % (3/14) and 25 % (1/4), respectively. The triple response was seen in three patients who had all been treated with PEG-IFN for 48 weeks.

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.

Biological properties of adrenomedullin conjugated with polyethylene glycol

Adrenomedullin (AM) is a vasodilator peptide with pleiotropic effects, including cardiovascular protection and anti-inflammation. Because of these beneficial effects, AM appears to be a promising therapeutic tool for human diseases, while intravenous injection of AM stimulates sympathetic nerve activity due to short-acting potent vasodilation, resulting in increased heart rate and renin secretion. To lessen these acute reactions, we conjugated the N-terminal of human AM peptide with polyethylene glycol (PEG), and examined the biological properties of PEGylated AM in the present study. PEGylated AM stimulated cAMP production, an intracellular second messenger of AM, in cultured human embryonic kidney cells expressing a specific AM receptor in a dose-dependent manner, as did native human AM. The pEC50 value of PEGylated AM was lower than human AM, but no difference was noted in maximum response (Emax) between the PEGylated and native peptides. Intravenous bolus injection of 10nmol/kg PEGylated AM lowered blood pressure in anesthetized rats, but the acute reduction became significantly smaller by PEGylation as compared with native AM. Plasma half-life of PEGylated AM was significantly longer than native AM both in the first and second phases in rats. In summary, N-terminal PEGylated AM stimulated cAMP production in vitro, showing lessened acute hypotensive action and a prolonged plasma half-life in comparison with native AM peptide in vivo.

Relevance of the Core 70 and IL-28B polymorphism and response-guided therapy of peginterferon alfa-2a ± ribavirin for chronic hepatitis C of Genotype 1b: a multicenter randomized trial, ReGIT-J study

BACKGROUND

We conducted a multicenter randomized clinical trial to determine the optimal treatment strategy against chronic hepatitis C virus (HCV) with genotype 1b and a high viral load (G1b/high).

METHODS

The study subjects included 153 patients with G1b/high. Patients were initially treated with PEG-IFNα-2a alone and then randomly assigned to receive different treatment regimens. Ribavirin (RBV) was administered to all patients with HCV RNA at week 4. Patients negative for HCV RNA at week 4 were randomly assigned to receive PEG-IFNα-2a (group A) or PEG-IFNα-2a/RBV (group B). Patients who showed HCV RNA at week 4 but were negative at week 12 were randomly assigned to receive weekly PEG-IFNα-2a (group C) or biweekly therapy (group D). Patients who showed HCV RNA at week 12 but were negative at week 24 were randomly assigned to receive PEG-IFNα-2a/RBV (group E) or PEG-IFNα-2a/RBV/fluvastatin (group F).

RESULTS

Overall, the rate of sustained virological response (SVR) was 46 % (70/153). The total SVR rate in the group (A, D, and F) of response-guided therapy was significantly higher than that in the group (B, C, and E) of conventional therapy [70 % (38/54) versus 52 % (32/61), p = 0.049]. Although IL28-B polymorphism and Core 70 mutation were significantly associated with efficacy, patients with rapid virological response (RVR) and complete early virological response (cEVR) achieved high SVR rates regardless of their status of IL-28B polymorphism and Core 70 mutation.

CONCLUSION

In addition to knowing the IL-28B polymorphism and Core 70 mutation status, understanding the likelihood of virological response during treatment is critical in determining the appropriate treatment strategy.

Peginterferon–α2a (40 kDa) (Pegasys®) for hepatitis B

Chronic hepatitis B virus is a serious and life threatening disease afflicting 350 million people worldwide, despite the availability of effective vaccines. Thus far, current monotherapy with conventional interferon-alpha, lamivudine and adefovir dipivoxil remains unsatisfactory. In addition, the use of conventional interferon-alpha needs to be administered subcutaneously three-times weekly and is associated with frequent adverse events. Although nucleoside/nucleotide analogs such as lamivudine and adefovir dipivoxil are well tolerated and can normalize serum alanine aminotransaminase rapidly, 1-year therapy with either lamivudine or adefovir dipivoxil results in low hepatitis B e antigen seroconversion rates. In hepatitis B e antigen-negative patients, most would relapse after lamivudine has been discontinued. Peginterferon-alpha2a, an immunomodulatory agent, is a new drug that has just completed Phase III clinical trials for the treatment of both hepatitis B e antigen-positive and -negative chronic hepatitis B virus infection. The advantage of peginterferon-alpha2a in achieving sustained virologic response over nucleoside/nucleotide analogs is particularly obvious in the hepatitis B e antigen-negative group. In both studies, sustained off-treatment response is superior to the use of monotherapy with lamivudine, and concomitant use of lamivudine and pegnterferon-alpha2a does not have advantages over the use of peginterferon-alpha2a alone. These recent data put peginterferon-alpha2a as the antihepatitis B virus therapy of choice, especially in young and motivated patients with chronic hepatitis B virus infection. However, despite the superiority of peginterferon-alpha2a over currently licensed nucleoside/nucleotide analogs, more research needs to be conducted in order to find the most optimal treatment regimen in our fight against chronic hepatitis B virus infection.

The fusion protein of IFN-α and apolipoprotein A-I crosses the blood-brain barrier by a saturable transport mechanism

IFN-α is widely used for the treatment of chronic viral hepatitis and malignancies. However, systemic IFN-α treatment causes severe neuropsychiatric complications in humans, including depression, anxiety, and cognitive impairments. We have previously reported that the fusion protein formed by IFN-α and apolipoprotein A-I (IA) circulates bound to high-density lipoproteins (HDLs) and exhibits liver targeting, increased half-life, enhanced immunostimulatory activity, and reduced cytotoxicity. As the transport of HDLs across the blood-brain barrier is a highly complex and regulated process, in this study, we examine the effects of IA on the brain. Determination of IFN-α in brain and serum after hydrodynamic administration of different doses of a plasmid encoding IFN-α or IA showed that IA penetrated into the brain by a saturable transport mechanism. Thus, at high serum levels of the transgenes, the induction of IFN-sensitive genes and the number of phospho-STAT1(+) cell nuclei in the brain were substantially higher with IFN-α than with IA. This was associated with attenuation of neurodepression in mice given IA, as manifested by shorter immobility time in the tail suspension test. However, when given low doses of rIFN-α or the same antiviral units of HDLs containing IA, the induction of IFN-stimulated genes in the brain was significantly greater with the latter. In conclusion, IA crosses the blood-brain barrier not by diffusion, as is the case of IFN-α, but by a facilitated saturable transport mechanism. Thus, linkage to apolipoprotein A-I may serve to modulate the effects of IFN-α on the CNS.

Effectiveness of biweekly low-dosage peginterferon treatment on the improvement of serum alanine aminotransferase and α-fetoprotein levels

AIM

  The purpose of this clinical study was to determine the effect of a biweekly low-dosage peginterferon α-2a treatment program on serum alanine aminotransferase (ALT) and α-fetoprotein (AFP) levels.

METHODS

  Fifty-five patients participated in the study. The inclusion criteria included chronic genotype 1b hepatitis C virus (HCV) infection, liver cirrhosis, or the absence of cirrhosis in subjects 65 years old or above, and interferon therapy naivety or a lack of sustained response to therapy with interferon-plus-ribavirin or peginterferon-plus-ribavirin. Patients were divided into naïve, relapser, and non-responder groups. The median age of the patients was 70 years, and 73% of patients had cirrhosis. All patients were treated with peginterferon α-2a at 90 µg biweekly.

RESULTS

  The rates of normalization (≤30 IU/l) of ALT levels at week 24 in the relapser group and the ≥2 log(10) HCV RNA decline group were high (74% and 68%, respectively). However, the ALT and AFP levels decreased significantly in each group, including the non-responder group. The ALT levels decreased significantly even in patients in whom the HCV RNA levels did not decrease. Furthermore, the AFP levels decreased significantly in the patients showing no decline in the ALT and HCV RNA levels. Only three patients discontinued treatment within 48 weeks due to adverse events, and more than 70% of the patients experienced no subjective symptoms during treatment.

CONCLUSION

  A biweekly low-dosage peginterferon α-2a therapy is effective for reducing the serum levels of ALT and AFP and may reduce hepatocarcinogenesis in patients with liver cirrhosis and in the elderly individuals.

Hyporesponsiveness to PegIFNα2B plus ribavirin in patients with hepatitis C-related advanced fibrosis

BACKGROUND & AIMS

The success of pegylated-interferon (PegIFN)/ribavirin (Rbv) therapy of chronic hepatitis C is compromised by liver fibrosis. Whether fibrosis equally affects the two PegIFNα-based therapies is unknown. To assess the response to the two PegIFN regimens in patients with different degree of liver fibrosis.

METHODS

A sub-analysis of the MIST study: 431 consecutive naïve patients randomly assigned, based on HCV genotype, to receive either (A) PegIFNα2a 180 μg/wk plus daily Rbv 800-1200 mg or (B) PegIFNα2b 1.5 μg/kg/week plus daily Rbv 800-1200 mg, were stratified according to Ishak staging (S) into mild (S0-S2) or moderate (S3, S4) fibrosis and cirrhosis (S5, S6).

RESULTS

In A the sustained virological response (SVR) rates were not significantly influenced by fibrosis stage (71% in S0-S2, 66% in S3, S4, 53% in S5, S6, p=0.12), compared to B where the SVR rates differed according to fibrosis stage (65%, 46%, and 38%, p=0.004, respectively). This was even more so in HCV-1/4 patients treated with PegIFNα2b where the SVR rates were twice as many in S0-S2 vs. S≥3 (44% vs. 22%, p=0.02), while in A the SVR rates were similar between the two fibrosis subgroups (S0-S2: 47% vs. S≥3: 48%, p=0.8). By logistic regression analysis genotype 1/4 and lack of rapid virological response were independent predictors of treatment failure in both treatment groups, while S≥3 fibrosis was associated to PegIFNα2b treatment failure, only (OR 2.83, 95% CI 1.4-5.68, p=0.004).

CONCLUSIONS

Liver fibrosis was an independent moderator of treatment outcome in patients receiving PegIFNα2b, not in those receiving PegIFNα2a.

Interferon-alpha administration enhances CD8+ T cell activation in HIV infection

Background

Type I interferons play important roles in innate immune defense. In HIV infection, type I interferons may delay disease progression by inhibiting viral replication while at the same time accelerating disease progression by contributing to chronic immune activation.

Methods

To investigate the effects of type I interferons in HIV-infection, we obtained cryopreserved peripheral blood mononuclear cell samples from 10 subjects who participated in AIDS Clinical Trials Group Study 5192, a trial investigating the activity of systemic administration of IFNα for twelve weeks to patients with untreated HIV infection. Using flow cytometry, we examined changes in cell cycle status and expression of activation antigens by circulating T cells and their maturation subsets before, during and after IFNα treatment.

Results

The proportion of CD38+HLA-DR+CD8+ T cells increased from a mean of 11.7% at baseline to 24.1% after twelve weeks of interferon treatment (p = 0.006). These frequencies dropped to an average of 20.1% six weeks after the end of treatment. In contrast to CD8+ T cells, the frequencies of activated CD4+ T cells did not change with administration of type I interferon (mean percentage of CD38+DR+ cells = 2.62% at baseline and 2.17% after 12 weeks of interferon therapy). As plasma HIV levels fell with interferon therapy, this was correlated with a “paradoxical” increase in CD8+ T cell activation (p<0.001).

Conclusion

Administration of type I interferon increased expression of the activation markers CD38 and HLA DR on CD8+ T cells but not on CD4+ T cells of HIV+ persons. These observations suggest that type I interferons may contribute to the high levels of CD8+ T cell activation that occur during HIV infection.

Antiviral drugs for viruses other than human immunodeficiency virus

Most viral diseases, with the exception of those caused by human immunodeficiency virus, are self-limited illnesses that do not require specific antiviral therapy. The currently available antiviral drugs target 3 main groups of viruses: herpes, hepatitis, and influenza viruses. With the exception of the antisense molecule fomivirsen, all antiherpes drugs inhibit viral replication by serving as competitive substrates for viral DNA polymerase. Drugs for the treatment of influenza inhibit the ion channel M(2) protein or the enzyme neuraminidase. Combination therapy with Interferon-α and ribavirin remains the backbone treatment for chronic hepatitis C; the addition of serine protease inhibitors improves the treatment outcome of patients infected with hepatitis C virus genotype 1. Chronic hepatitis B can be treated with interferon or a combination of nucleos(t)ide analogues. Notably, almost all the nucleos(t) ide analogues for the treatment of chronic hepatitis B possess anti-human immunodeficiency virus properties, and they inhibit replication of hepatitis B virus by serving as competitive substrates for its DNA polymerase. Some antiviral drugs possess multiple potential clinical applications, such as ribavirin for the treatment of chronic hepatitis C and respiratory syncytial virus and cidofovir for the treatment of cytomegalovirus and other DNA viruses. Drug resistance is an emerging threat to the clinical utility of antiviral drugs. The major mechanisms for drug resistance are mutations in the viral DNA polymerase gene or in genes that encode for the viral kinases required for the activation of certain drugs such as acyclovir and ganciclovir. Widespread antiviral resistance has limited the clinical utility of M(2) inhibitors for the prevention and treatment of influenza infections. This article provides an overview of clinically available antiviral drugs for the primary care physician, with a special focus on pharmacology, clinical uses, and adverse effects.

Preparation of CHO cell-derived rhIFN-ω-Fc with improved pharmacokinetics

Interferon-omega (IFN-ω) may be a useful, promising and alternative antiviral agent, in addition to IFN-α-2a and IFN-α-2b. To improve the pharmacokinetics of IFN-ω for clinical use, the recombinant human IFN-ω-Fc fusion protein (rhIFN-ω-Fc) was expressed in a Chinese hamster ovary cell line (CHO-S), due to the longer serum half-life of rhIFN-ω-Fc compared to the native IFN-ω protein, and purified by affinity chromatography. Physicochemical characterization of the purified fusion protein was performed by SDS-PAGE electrophoresis, dot blot analysis and N-terminal amino acid sequence analysis. The results show that rhIFN-ω-Fc was highly expressed at the predicted size and with the N-terminal amino acid sequence. The antiviral activity was determined by the ability of IFNs to inhibit the cytopathic effects (CPEs) of vesicular stomatitis virus (VSV) on the human amnion WISH cells. The rhIFN-ω-Fc expressed in CHO-S cells has a specific activity of 1.6×10(7) IU/mg compared to rhIFN-ω expressed in yeast, which has a specific activity of 7×10(7) IU/mg. Equimolar concentrations of rhFN-ω and rhIFN-ω-Fc were administered to rabbits for pharmacokinetics comparison. The terminal half-life of rhIFN-ω-Fc was 35 times higher than that of rhIFN-ω. Thus, rhIFN-ω-Fc can be used as a prospective antiviral candidate especially for the treatment of chronic viral disease, such as hepatitis C virus (HCV) infection.

Intermolecular interactions in a 44 kDa interferon-receptor complex detected by asymmetric reverse-protonation and two-dimensional NOESY

Type I interferons (IFNs) make up a family of homologous helical cytokines initiating strong antiviral and antiproliferative activity. All type I IFNs bind to a common cell surface receptor consisting of two subunits, IFNAR1 and IFNAR2, associating upon binding of interferon. We studied intermolecular interactions between IFNAR2-EC and IFNalpha2 using asymmetric reverse-protonation of the different complex components and two-dimensional homonuclear NOESY. This new approach revealed with an excellent signal-to-noise ratio 24 new intermolecular NOEs between the two molecules despite the low concentration of the complex (0.25 mM) and its high molecular mass (44 kDa). Sequential and side chain assignment of IFNAR2-EC and IFNalpha2 in their binary complex helped assign the intermolecular NOEs to the corresponding protons. A docking model of the IFNAR2-EC-IFNalpha2 complex was calculated on the basis of the intermolecular interactions found in this study as well as four double mutant cycle constraints, previously observed NOEs between a single pair of residues and the NMR mapping of the binding sites on IFNAR2-EC and IFNalpha2. Our docking model doubles the buried surface area of the previous model and significantly increases the number of intermolecular hydrogen bonds, salt bridges, and van der Waals interactions. Furthermore, our model reveals the participation of several new regions in the binding site such as the N-terminus and A helix of IFNalpha2 and the C domain of IFNAR2-EC. As a result of these additions, the orientation of IFNAR2-EC relative to IFNalpha2 has changed by 30 degrees in comparison with a previously calculated model that was based on NMR mapping of the binding sites and double mutant cycle constraints. In addition, the new model strongly supports the recently proposed allosteric changes in IFNalpha2 upon binding of IFNAR1-EC to the binary IFNalpha2-IFNAR2-EC complex.

Pegylated IFN-α2a combined to imatinib mesylate 600mg daily can induce complete cytogenetic and molecular responses in a subset of chronic phase CML patients refractory to IFN alone or to imatinib 600mg daily alone

This phase I/II study was designed to demonstrate the tolerance and the efficacy of a combination of pegylated interferon-α 2a to Imatinib mesylate (IM) 600mg daily in cytogenetically IM-resistant but in CHR chronic phase CML patients. The combination was generally well tolerated in the 15 evaluable patients. A significant reduction of the Ph1(+) BM metaphases was observed in these poor prognosis patients, with 2 long-term CCyR including 2 MMR. After a median follow-up of 43 months, 93% of patients are alive. The addition of PegIFNα2a to IM600 is feasible, and able to overcome resistance within this context.

Safety, tolerability, and mechanisms of antiretroviral activity of pegylated interferon Alfa-2a in HIV-1-monoinfected participants: a phase II clinical trial

BACKGROUND

To our knowledge, the antiviral activity of pegylated interferon alfa-2a has not been studied in participants with untreated human immunodeficiency virus type 1 (HIV-1) infection but without chronic hepatitis C virus (HCV) infection.

METHODS

Untreated HIV-1-infected volunteers without HCV infection received 180 microg of pegylated interferon alfa-2a weekly for 12 weeks. Changes in plasma HIV-1 RNA load, CD4(+) T cell counts, pharmacokinetics, pharmacodynamic measurements of 2',5'-oligoadenylate synthetase (OAS) activity, and induction levels of interferon-inducible genes (IFIGs) were measured. Nonparametric statistical analysis was performed.

RESULTS

Eleven participants completed 12 weeks of therapy. The median plasma viral load decrease and change in CD4(+) T cell counts at week 12 were 0.61 log(10) copies/mL (90% confidence interval [CI], 0.20-1.18 log(10) copies/mL) and -44 cells/microL (90% CI, -95 to 85 cells/microL), respectively. There was no correlation between plasma viral load decreases and concurrent pegylated interferon plasma concentrations. However, participants with larger increases in OAS level exhibited greater decreases in plasma viral load at weeks 1 and 2 (r = -0.75 [90% CI, -0.93 to -0.28] and r = -0.61 [90% CI, -0.87 to -0.09], respectively; estimated Spearman rank correlation). Participants with higher baseline IFIG levels had smaller week 12 decreases in plasma viral load (0.66 log(10) copies/mL [90% CI, 0.06-0.91 log(10) copies/mL]), whereas those with larger IFIG induction levels exhibited larger decreases in plasma viral load (-0.74 log(10) copies/mL [90% CI, -0.93 to -0.21 log(10) copies/mL]).

CONCLUSION

Pegylated interferon alfa-2a was well tolerated and exhibited statistically significant anti-HIV-1 activity in HIV-1-monoinfected patients. The anti-HIV-1 effect correlated with OAS protein levels (weeks 1 and 2) and IFIG induction levels (week 12) but not with pegylated interferon concentrations.

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.

Randomized study of peginterferon-alpha2a plus ribavirin vs peginterferon-alpha2b plus ribavirin in chronic hepatitis C

BACKGROUND & AIMS

Ribavirin (RBV) combined with either pegylated interferon (PegIFN) alpha2a or PegIFNalpha2b is the standard of care for chronic hepatitis C virus (HCV) infection. Due to the lack of head-to-head studies, the 2 PegIFNs have not been directly compared. The endpoints of our study were safety and antiviral efficacy of the 2 regimens.

METHODS

Treatment-naïve patients with chronic hepatitis C were randomly (1:1) assigned after stratification for HCV genotype to receive either 1.5 mcg/Kg/week PegIFNalpha2b plus RBV 800-1200 mg/day or 180 mcg/week PegIFNalpha2a plus RBV 800-1200 mg/day for 24 or 48 weeks according to HCV genotype. The study was powered to detect a difference of at least 10% in safety and efficacy of the 2 regimens.

RESULTS

The 212 patients on PegIFNalpha2a and the 219 patients on PegIFNalpha2b had similar baseline characteristics, including cirrhosis (20% vs 18%, respectively). By intention to treat, the 2 groups showed similar rates of treatment-related serious adverse events (1% vs 1%, respectively) and drop out rates for adverse effects (7% vs 6%, respectively). Overall, sustained virologic response (SVR) rate was higher in PegIFNalpha2a than in PegIFNalpha2b patients (66% vs 54%, respectively, P = .02), being 48% vs 32% in the 222 HCV-1 and -4 patients (P = .04), and 96% vs 82%, respectively, in the 143 HCV-2 patients (P = .01). PegIFNalpha2a independently predicted SVR in the logistic regression analysis (odds ratio, 1.88; 95% confidence interval: 1.20-2.96).

CONCLUSIONS

Although the 2 regimens showed a similar safety profile, the PegIFNalpha2a-based treatment yielded significantly more SVR than PegIFNalpha2b.

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.

Impact of obesity, steatosis and insulin resistance on progression and response to therapy of hepatitis C

Clinical progression of chronic hepatitis C depends on several cofactors, which also have a negative affect on the rate of response to interferon-alpha-based therapy. Given the current worldwide prevalence of the metabolic syndrome, the impact of obesity and insulin resistance, and of their histopathological correlate, hepatic steatosis, on the natural history and management of chronic hepatitis C is undoubtedly very important. We will review some of the current knowledge on the clinical consequences of overweight/obesity, steatosis and insulin resistance on chronic hepatitis C, and discuss how this issue may be dealt with in clinical practice.

Multimeric peptide-based PEG nanocarriers with programmable elimination properties

In the current study, the design, synthetic feasibility and biochemical characterization of biodegradable peptidic PEG-based nanocarriers are described. The components were selected to influence the body elimination pathway upon nanocarrier biodegradation. Two prototypical nanocarriers were prepared using non-PEGylated and PEGylated peptidic cores [CH(3)CO-(Lys-betaAla-betaAla)(X)-Cys-CONH(2) (X=2, 4)]. A homodimeric nanocarrier with 4 copies of fluorescein-PEG5kDa was synthesized by linking two PEGylated peptidic cores (X=2) using a disulfide bond. A dual labeled heterodimeric nanocarrier with 2 copies of fluorescein-PEG5kDa and 4 copies of Texas Red was also synthesized. Optimum conditions for linking imaging agents, PEG, or a peptidic core to a peptidic core were determined. Significantly higher yields (69% versus 30%) of the PEGylated peptidic core were obtained by using 2 copies of beta-alanine as a spacer along with increasing DMSO concentrations, which resulted in reduced steric hindrance. Stoichiometric addition of the components was also demonstrated and found to be important for reducing polydispersity. Nanocarrier biodegradation was evaluated in simulated intracellular and extracellular/blood environments using 3 mm and 10 microm glutathione in buffer, respectively. The nanocarrier was 9-fold more stable in the extracellular environment. The results suggest selective intracellular degradation of the nanocarrier into components with known body elimination pathways.

Clinical significance of 4 patients with chronic hepatitis B achieving HBsAg clearance by treated with pegylated interferon alpha-2a for less than 1 year: a short report

We report 4 chinese patients with hepatitis B e antigen-positive chronic hepatitis B achieving clearance of HBsAg by using pegylated interferon alpha-2a for less than 1 year, to provide one clinical clue for the treatment of chronic hepatitis B.

Phase II, randomized, multicenter, comparative study of peginterferon–α–2a (40 kD) (Pegasys®)versusinterferon α-2a (Roferon®-A) in patients with treatment-naïve, chronic-phase chronic myelogenous leukemia

The efficacy and safety of peginterferon-alpha-2a (40 kD) (PEG-IFNalpha-2a), 450 microg once weekly, versus IFNalpha-2a, 9 MIU once daily, for 12 months, was evaluated in a Phase II study in IFN-naïve patients with chronic-phase, Philadelphia-chromosome-positive CML. At the end of the treatment, complete hematological response was observed in 66.2% (47/71) and 45.2% (33/73) of the PEG-IFNalpha-2a group and IFNalpha-2a groups, respectively (p = 0.009), and major cytogenetic response occurred in 35.2% and 17.8%, respectively (p = 0.016). PEG-IFNalpha-2a was at least as effective as IFNalpha-2a overall, including progression-free survival at the end of treatment, and overall survival after 30 months of follow-up. Adverse events necessitated fewer withdrawals but more dose adjustments in the PEG-IFNalpha-2a group compared with the IFNalpha-2a group (11%versus 23%, and 84.5%versus 65.8%, respectively). In conclusion, PEG-IFNalpha-2a (40 kD), 450 microg once weekly, compared with IFNalpha-2a, 9 MIU once daily, resulted in higher rates of hematologic and cytogenetic response and greater overall survival.

Current status and challenges of cytokine pharmacology

The major concern of pharmacology about cytokines has originated from plentiful data showing association between gross changes in their production and pathophysiological processes. Despite the enigmatic role of cytokines in diseases, a number of them have become a subject of cytokine and anti-cytokine immunotherapies. Production of cytokines can be influenced by many endogenous and exogenous stimuli including drugs. Cells of the immune system, such as macrophages and lymphocytes, are richly endowed with receptors for the mediators of physiological functions, such as biogenic amines, adenosine, prostanoids, steroids, etc. Drugs, agonists or antagonists of these receptors can directly or indirectly up- and down-regulate secretion of cytokines and expression of cytokine receptors. Vice versa, cytokines interfere with drug pharmacokinetics and pharmacodynamics through the interactions with cytochrome P450 and multiple drug resistance proteins. The aim of the review is to encourage more intensive studies in these fields of cytokine pharmacology. It also outlines major areas of searching promising candidates for immunotherapeutic interventions.

Pegylated alpha-interferon-2a plus ribavirin compared with pegylated alpha-interferon-2b plus ribavirin for initial treatment of chronic hepatitis C virus: prospective, non-randomized study

BACKGROUND AND AIM

We assessed whether the two regimens of pegylated alpha-interferon-2b (PEG-IFN-alpha2b) plus ribavirin and pegylated alpha-interferon-2a (PEG-IFN-alpha2a) plus ribavirin showed differences in terms of sustained virological response, withdrawal due to side-effects and dose adjustment requirements in the treatment of naive chronic hepatitis C virus (HCV) patients.

METHODS

A prospective non-randomized, open-label comparison was made of naive HCV-infected patients undergoing standard 24- or 48-week treatment with two PEG-IFN combined with weight-based dosing regimen of ribavirin (PEG-IFN-alpha2a/ribavirin, n = 91; PEG-IFN-alpha2b/ribavirin, n = 92).

RESULTS

Sustained virological response was similar in PEG-IFN-alpha2a and PEG-IFN-alpha2b (65.9% vs 62%, P = 0.64), without differences according to genotype. In 117 patients with HCV genotype 1, the corresponding rates were 50.8% versus 46.6% (P = 0.713). Rapid virological response at 4 weeks, early virological response at 12 weeks and transient virological response were also similar. In the multivariate analysis, HCV genotype (odds ratio [OR] = 0.076, 95% confidence interval [CI] 0.029-0.198, P = 0.000) and presence of steatosis in the liver biopsy (OR = 2.799, 95% CI 1.362-5.755, P = 0.005) were significantly associated with response to antiviral therapy. The rate of withdrawals due to treatment-related adverse events was 13.2% in the group of PEG-IFN-alpha2a and 10.9% in the group of PEG-IFN-alpha2b. Dose modification of PEG-IFN was necessary in eight patients given PEG-IFN-alpha2a and in seven given PEG-IFN-alpha2b.

CONCLUSION

The two PEG-IFN plus ribavirin have comparable anti-HCV activity as shown by similar percentages of patients with sustained virological response.

Sustained response to peginterferon alfa-2a (40 kD) with or without lamivudine in Asian patients with HBeAg-positive and HBeAg-negative chronic hepatitis B

PURPOSE

The 2 reported trials investigated the effectiveness of treatment with peginterferon alfa-2a in Asian patients with chronic hepatitis B (CHB).

METHODS

Patients with HBeAg-positive (n = 708) or HBeAg-negative (n = 332) CHB were enrolled in 2 randomized, double blind, placebo-controlled studies. Patients received peginterferon alfa-2a 180 mug once weekly, peginterferon plus lamivudine 100 mg per day, or lamivudine alone for 48 weeks. Patients were followed up at 6 and 12 months posttreatment.

RESULTS

Peginterferon alfa-2a provided significantly higher rates of HBeAg seroconversion (31%) in HBeAg-positive patients than did lamivudine (19%, P = 0.005) 6 months posttreatment, irrespective of genotype. Of these, 83% achieving seroconversion during treatment or early posttreatment sustained their response at 12 months posttreatment. In patients who seroconverted, 69% maintained HBV DNA suppression at <10,000 copies/ml and alanine aminotrasferase (ALT) normalization. In HBeAg-negative patients, peginterferon produced a significantly higher combined response of HBV DNA at <20,000 copies/ml and ALT normalization (45%) than lamivudine (31%, P = 0.032), irrespective of genotype. Almost 80% of these patients sustained their response at 12 months posttreatment.

CONCLUSIONS

In conclusion, a finite course of peginterferon alfa-2a provides significant and sustained treatment benefit in Asian CHB patients, who have traditionally been regarded as difficult to treat.

Combination therapy with PEG-IFN-alpha and 5-FU inhibits HepG2 tumour cell growth in nude mice by apoptosis of p53

When the tumour suppressor p53 is activated by DNA damage, it stimulates the transcription of its target genes, which then induce cell cycle arrest or apoptosis. Here, we examined the role p53 plays in the antitumour effect of combination treatment with pegylated interferon (PEG-IFN)-alpha and 5-fluorouracil (5-FU), which has been shown to effectively treat advanced hepatocellular carcinoma (HCC). Nude mice were injected subcutaneously with cultured HepG2 cells, in which p53 is functional. They were treated a week later with PEG-IFN and/or 5-FU for 7 weeks, after which we measured and examined their tumours. Combination groups showed significantly lower tumour volumes and higher tumour cell apoptosis than the other groups. Combination treatment and PEG-IFN monotherapy also significantly elevated the p53 protein and mRNA levels in the tumour but only combination treatment increased the degree of p53 phosphorylation at serine46 and induced p53-regulated apoptosis-inducing protein 1 (p53AIP1) expression. The antitumour effects of combination treatment is due in part to the elevation by PEG-IFN of p53 protein and mRNA expression and in part to the DNA damage that is generated by 5-FU, which induces p53 serine46 phosphorylation, which in turn upregulates p53AIP1 expression.

Etiologic treatment of hepatitis C virus-associated mixed cryoglobulinemia

The treatment of mixed cryoglobulinemia (MC) includes several drugs--steroids, cyclosporins, colchicine, plasmapheresis--but given the documented association between MC and hepatitis C virus (HCV), the treatment of choice seems to be antiviral therapy. Several authors have reported the efficacy of interferon (IFN) alpha in the inhibition of HCV replication and reduction of cryoglobulin levels. The therapy with IFN as monotherapy in MC shows a complete response rate in only 10 -12% of cases. Complete response to therapy using a combination of IFN plus ribavirin varies in different studies from 18% to 64% of cases. There are only two studies on the treatment of MC with peginterferon plus ribavirin. Both studies, given the high number of complete responders, reinforce the idea that peginterferon plus ribavirin is, at present, the best available treatment for cryoglobulinemic syndrome. The results obtained with peginterferon combined therapy are superior to standard interferon plus ribavirin in treatment-naive patients. In fact, a sustained virological response was observed in 44% of patients; the same results were obtained for clinical (purpura and arthralgia disappearance) and biochemical (aminotransaminases normalization) responses. New drug combinations, like peginterferons plus anti-CD20 antibodies, should be considered for treatment of MC in the future.

A randomized, controlled trial of postoperative adjuvant interferon therapy after resection of hepatocellular carcinoma

OBJECTIVE

We conducted a randomized controlled trial of adjuvant interferon therapy in patients with predominantly hepatitis B-related hepatocellular carcinoma (HCC) to investigate whether the prognosis after hepatic resection could be improved.

SUMMARY BACKGROUND DATA

Recurrence is common after hepatic resection for HCC. Interferon possesses antiviral, immunomodulatory, antiproliferative, and antiangiogenic effects and may be an effective form of adjuvant therapy.

PATIENTS AND METHODS

Since February 1999, patients with no residual disease after hepatic resection for HCC were randomly assigned with stratification by pTNM stage to receive no treatment (control group), interferon alpha-2b 10 MIU/m (IFN-I group) or 30 MIU/m (IFN-II group) thrice weekly for 16 weeks. Enrollment to the IFN-II group was terminated from January 2000 because adverse effects resulted in treatment discontinuation in the first 6 patients. By June 2002, 40 patients each had been enrolled into the control group and IFN-I group. The baseline clinical, laboratory, and tumor characteristics of both groups were comparable.

RESULTS

The 1- and 5-year survival rates were 85% and 61%, respectively, for the control group and 97% and 79%, respectively, for the IFN-I group (P = 0.137). After adjusting for the confounding prognostic factors in a Cox model, the relative risk of death for interferon treatment was 0.42 (95% CI, 0.17-1.05; P = 0.063). Exploratory subset analysis showed that adjuvant interferon had no survival benefit for pTNM stage I/II tumor (5-year survival 90% in both groups; P = 0.917) but prevented early recurrence and improved the 5-year survival of patients with stage III/IVA tumor from 24% to 68% (P = 0.038).

CONCLUSION

In a group of patients with predominantly hepatitis B-related HCC, adjuvant interferon therapy showed a trend for survival benefit, primarily in those with pTNM stage III/IVA tumors. Further larger randomized trials stratified for stage are needed.

New and emerging treatment of chronic hepatitis B

Conventional treatment of chronic hepatitis B with interferon alfa-2b, lamivudine, and adefovir is limited by low rates of sustained hepatitis B virus DNA suppression and hepatitis B e antigen (HBeAg) seroconversion, increasing rates of drug resistance to the oral agents, and poor tolerability of interferon. Recently several promising new antiviral agents have emerged that possess potent antiviral effects, less toxicity, and have little or no risk of drug resistance. Two new agents, entecavir and peginterferon alfa-2a, have received recent approval by regulatory authorities in the United States and several other countries for the treatment of adults with chronic hepatitis B. In large phase III clinical trials, these agents have demonstrated superior efficacy over lamivudine in both HBeAg-positive and HBeAg-negative patients. Drug resistance occurs at a low rate in lamivudine-refractory patients treated with entecavir or is, to date, nonexistent in nucleoside-naïve patients treated with entecavir and all patients receiving peginterferon. In addition, several novel agents in clinical development, such as emtricitabine, clevudine, telbivudine, valtorcitabine, and tenofovir, have shown promising clinical profiles in patients with chronic hepatitis B. This review summarizes the recent clinical studies of these new agents and discusses the implications of these data for the management of chronic hepatitis B.

Preparation and characterization of a potent, long-lasting recombinant human serum albumin-interferon-alpha2b fusion protein expressed in Pichia pastoris

A long-lasting recombinant human serum albumin-interferon-alpha2b fusion protein (rHSA/IFNalpha2b) was prepared and its structure and biological activities were studied. rHSA/IFNalpha2b was expressed in methylotrophic yeast Pichia pastoris with HSA's natural signal peptide and purified by dye affinity chromatography, hydrophobic interaction chromatography, ion exchange chromatography and Sephadex G25. Purity of the prepared rHSA/IFNalpha2b was greater than 97% analyzed by non-reduced SDS-PAGE and RP-HPLC. Structure and biological activities of the prepared rHSA/IFNalpha2b were characterized by physical, chemical and biological methods. Its pI was 5.3 and showed a single band on IEF gel. Molecular weight determined by MALDI-TOF was 86004.3+/-29.2. Amino-terminal and carboxyl-terminal amino acid sequences were identical to predicted sequence. Its specific activity in vitro was 6.3+/-0.8x10(5) IU/mg fusion protein, retaining about 1.4% of that of unmodified rIFNalpha on a molar basis. After administered in monkeys, significant increases of 2',5'-oligoadenylate synthetase activity relative to IFN-alpha were maintained for 14 days in serum and the rHSA/IFNalpha2b showed more potent biological activity than IFN-alpha on a molar basis. Therefore, markedly improved in vivo biological activity of rHSA/IFNalpha2b could exhibit more potent antiviral activity than IFNalpha2b in future clinical trials.

PEG-IFN-α-2b therapy in BCR-ABL–negative myeloproliferative disorders

BACKGROUND

Interferon-alpha (IFN-alpha) has shown significant activity in the treatment of BCR-ABL-negative myeloproliferative disorders (MPDs), particularly essential thrombocythemia (ET) and polycythemia vera (PV). PEG-IFN-alpha-2b is a pegylated IFN-alpha-2b with a significant advantage over nonpegylated form in that it is administered once a week.

METHODS

Thirty-eight patients with BCR-ABL-negative MPDs were treated with PEG-IFN-alpha-2b, given subcutaneously weekly, at the starting dose of 3 microg/kg/wk for the first 14 patients and then 2 microg/kg/wk for the next 24 patients, with intent to treat patients as long as they benefited from the therapy.

RESULTS

Median age was 54 years. Patient diagnoses were: 13 (34%) ET; 11 (29%) primary myelofibrosis (PMF); 5 (13%) BCR-ABL-negative chronic myeloid leukemia (CML); 4 (10.5%) hypereosinophilic syndrome (HES); 4 (10.5%) PV; and 1 (3%) unclassified myeloproliferative disease (uMPD). Recorded grade 3-4 toxicities were related to fatigue, myelosuppression, and musculoskeletal pain. Ten (26%) patients stopped treatment because of toxicity. Thirteen (34%) patients achieved a complete remission, and 4 (11%) achieved a partial response. Only 1 patient with PMF responded. Median time to response was 5 months. Median duration of response was 20 months. Three patients had a sustained response for >24 months.

CONCLUSIONS

PEG-IFN-alpha-2b, with proper dose modifications, is effective in controlling disease in a significant proportion of BCR-ABL-negative MPD patients, particularly ET and PV. However, toxicities encountered with PEG-IFN-alpha-2b therapy are similar to those obtained with conventional IFN-alpha, thus limiting the duration of therapy.

Chronic Hepatitis B and C--current treatment and future therapeutic prospects

In chronic hepatitis B treatment with pegylated interferon can now be considered as therapy of choice in both HBeAg positive and HBeAg negative patients and seems to be more effective than lamivudine monotherapy. Alternatively, treatment with lamivudine is able to suppress HBV DNA and to induce HBeAg conversation in up to 30 % of the patients. In HBeAg negative chronic hepatitis B lamivudine has a similar efficiency in suppressing HBV DNA as in HBeAg positive patients. The frequently developing lamivudine resistant HBV variants can now be successfully be treated with adevofir dipivoxil in both forms of chronic hepatitis B. These nucleosides analogues are generally better tolerated than interferon and can also be given in patients with HBV related liver cirrhosis. Our therapeutic armamentarium will be expanded in the near future by other nucleoside analogues such as entecavir, emtricitapine, telbivudine or clevudine. The treatment of choice in chronic hepatitis C currently is pegylated interferon plus ribavirin. This regimen is able to induce a sustained virologic response in 50 % of treatment naïve cases. The limited effectiveness of this therapeutic approach makes additional drugs highly warranted and inhibitors of the NS3-4a protease region or the NS5B polymerase region of the viral genome are under development. In addition, HCV replication inhibitors based on RNA interference (siRNA) or agonists of toll like receptors (TLR), which are part of the inborn immune system recognizing the presence of invading microorganisms, are currently explored as agents active in inhibiting HCV replication. Although none of these drugs are currently licensed for HCV treatment they are promising antiviral candidates for the future.

Determination of the human type I interferon receptor binding site on human interferon-alpha2 by cross saturation and an NMR-based model of the complex

Type I interferons (IFNs) are a family of homologous helical cytokines that exhibit pleiotropic effects on a wide variety of cell types, including antiviral activity and antibacterial, antiprozoal, immunomodulatory, and cell growth regulatory functions. Consequently, IFNs are the human proteins most widely used in the treatment of several kinds of cancer, hepatitis C, and multiple sclerosis. All type I IFNs bind to a cell surface receptor consisting of two subunits, IFNAR1 and IFNAR2, associating upon binding of interferon. The structure of the extracellular domain of IFNAR2 (R2-EC) was solved recently. Here we study the complex and the binding interface of IFNalpha2 with R2-EC using multidimensional NMR techniques. NMR shows that IFNalpha2 does not undergo significant structural changes upon binding to its receptor, suggesting a lock-and-key mechanism for binding. Cross saturation experiments were used to determine the receptor binding site upon IFNalpha2. The NMR data and previously published mutagenesis data were used to derive a docking model of the complex with an RMSD of 1 Angstrom, and its well-defined orientation between IFNalpha2 and R2-EC and the structural quality greatly improve upon previously suggested models. The relative ligand-receptor orientation is believed to be important for interferon signaling and possibly one of the parameters that distinguish the different IFN I subtypes. This structural information provides important insight into interferon signaling processes and may allow improvement in the development of therapeutically used IFNs and IFN-like molecules.

An overview of psychiatric issues in liver disease for the consultation-liaison psychiatrist

Liver disease is a common cause of morbidity and mortality in the United States and elsewhere. Arising from infectious, hereditary, or toxin-induced sources, the detection of liver disease often requires a high index of suspicion. Clinical presentations are highly variable and are often accompanied by neuropsychiatric symptoms. This fact, along with an increased incidence of liver disease among patients with primary psychiatric disorders and the presence of varied drug use, complicates the tasks of providing care to patients with liver disease. To assist the consultation-liaison psychiatrist, the authors present the first of a two-part series focused on psychiatric issues in liver disease.

Impact of obesity on treatment of chronic hepatitis C

Obesity and the metabolic syndrome have hepatic manifestations, including steatosis and progression of fibrosis. In individuals with chronic hepatitis C, obesity is associated with inflammation, insulin resistance, steatosis, progression of fibrosis, and nonresponse to treatment with interferon or peginterferon alpha and ribavirin. Patients with both hepatitis C and obesity-related nonalcoholic fatty liver disease are at greater risk for more advanced liver disease. We review the mechanisms by which obesity may be associated with decreased efficacy of interferon-based therapies in individuals with chronic hepatitis C and the therapeutic strategies that may increase the effectiveness of these therapies in obese individuals.

Peginterferon-alpha 2a for the treatment of hepatitis B infection

Chronic hepatitis B is one of the world's most common serious diseases with > 300 million patients worldwide. Currently recommended treatments include conventional interferon (IFN), lamivudine and adefovir. Recently, peginterferon-alpha2a (PEG-IFN-alpha2a, Pegasys; Hoffmann-La Roche & Co.) has been approved for use in patients with chronic hepatitis B in the US, the EU, Switzerland, Turkey and in several countries in the Asia-Pacific region. Several trials have been carried out using PEG-IFN-alpha2a (40 kDa) compared with conventional IFN, lamivudine monotherapy and a combination of PEG-IFN-alpha2a and lamivudine in patients with hepatitis Be antigen- (HBeAg) positive chronic hepatitis B, and patients with HBeAg-negative chronic hepatitis B. PEG-IFN-alpha2a was shown to be superior to conventional IFN in HBeAg-positive disease and to lamivudine in both HBeAg-positive and HBeAg-negative chronic hepatitis B. Although there was greater suppression of virus while on therapy, the combination of lamivudine and PEG-IFN-alpha2a did not enhance sustained response at the end of the 24-week follow-up period, compared with PEG-IFN monotherapy. In addition, approximately 3% of patients underwent hepatitis B surface antigen (HBsAg) seroconversion - the ultimate marker of therapeutic response, which is rarely seen following treatment with antiviral agents. The side effect profile was reasonable. PEG-IFN-alpha2a could become the treatment of choice in many patients with both HBeAg-positive and HBeAg-negative disease and, in those who fail to respond, consideration could then be given to the use of antiviral agents.