Peginterferon-α2b and ribavirin

Coating Matters: Review on Colloidal Stability of Nanoparticles with Biocompatible Coatings in Biological Media, Living Cells and Organisms

Within the last two decades, the field of nanomedicine has not developed as successfully as has widely been hoped for. The main reason for this is the immense complexity of the biological systems, including the physico-chemical properties of the biological fluids as well as the biochemistry and the physiology of living systems. The nanoparticles' physicochemical properties are also highly important. These differ profoundly from those of freshly synthesized particles when applied in biological/living systems as recent research in this field reveals. The physico-chemical properties of nanoparticles are predefined by their structural and functional design (core and coating material) and are highly affected by their interaction with the environment (temperature, pH, salt, proteins, cells). Since the coating material is the first part of the particle to come in contact with the environment, it does not only provide biocompatibility, but also defines the behavior (e.g. colloidal stability) and the fate (degradation, excretion, accumulation) of nanoparticles in the living systems. Hence, the coating matters, particularly for a nanoparticle system for biomedical applications, which has to fulfill its task in the complex environment of biological fluids, cells and organisms. In this review, we evaluate the performance of different coating materials for nanoparticles concerning their ability to provide colloidal stability in biological media and living systems.

PEGylated interferon displays differences in plasma clearance and bioavailability between male and female mice and between female immunocompetent C57Bl/6J and athymic nude mice

Gender and immune status can considerably impact on the pharmacokinetics (PK) of macromolecular and small molecule drugs. However, these effects are often not considered in drug development. We aimed to quantitatively evaluate effects of gender and immune status on the PK of PEGylated interferon in frequently used murine models. Chronically cannulated female athymic nude and female and male immunocompetent C57Bl/6J mice (n = 24 in total) received a single intravenous or subcutaneous (s.c.) dose of PEGylated interferon. Serial blood samples were taken for 48 h. Noncompartmental analysis and population PK modeling with covariate analysis were performed to evaluate the data. The PK of PEGylated interferon followed a three compartment disposition model with two sequential compartments for s.c. absorption. Female nude mice had significantly higher plasma clearance than C57Bl/6J mice (0.503 vs. 0.397 mL/h). Male mice had a slower absorption rate constant (0.138 h(-1)) and extent (46.2%) of s.c. absorption than female mice (0.274 in C57Bl/6J and 0.374 h(-1) in nude, 60.8% in both). Thus, gender and immune status significantly impacted on important PK parameters of PEGylated interferon in murine models commonly utilized in drug development. It is critical to take into account these differences when choosing animal models and conducting translational pharmacology research.

Hepatitis C drug discovery: in vitro and in vivo systems and drugs in the pipeline

The combination therapy of ribavirin and pegylated interferon-alpha for hepatitis C has significant side effects, is often poorly tolerated and is ineffective in many patients, despite causing impressive improvement in the sustained virological response. Discovery and development of more effective and well-tolerated antihepatitis C virus drugs are clearly in great demand. During the past few years, remarkable advances have been made in the establishment of in vitro and in vivo systems. Armed with these systems, a wave of specific antihepatitis C virus compounds have been discovered and are moving into the clinical phase. More effective combination therapies with specific antivirals are predicted to emerge in the near future for the treatment of hepatitis C.

Ischemic colitis with type I interferons used in the treatment of hepatitis C and multiple sclerosis: an evaluation from the food and drug administration adverse event reporting system and review of the literature

OBJECTIVE

To better characterize the association between type I interferons and ischemic colitis (IC) in patients with the hepatitis C virus (HCV) and multiple sclerosis (MS), by analyzing reports submitted to the Food and Drug Administration (FDA) Adverse Event Reporting System (AERS) and the published literature.

DATA SOURCES

A total of 2,562,390 reports of adverse events between January 2003 and June 2011 were downloaded from the FDA AERS. A literature review was performed on PubMed (January 1966-August 2012) using the MeSH terms interferon or interferon alfa or interferon beta and ischemic colitis separated by the Boolean operator "and" between the first 3 terms and the last term. Additional literature was identified by conducting a hand search of the reference list of the published literature identified in the initial search.

STUDY SELECTION AND DATA EXTRACTION

Cases were restricted to those with an indication of HCV or MS, a primary suspect drug of a type I interferon, and a reaction of IC. Full-length reports were requested and organized by type of interferon, age, sex, concomitant drugs, and comorbidities. The Naranjo probability scale was used to define cases as definite, probable, possible, or doubtful drug-induced adverse events.

DATA SYNTHESIS

Type I interferons, including interferon alfa (IFN-α) and interferon beta (IFN-β), are approved for the treatment of HCV and MS. IFN-α has been shown to induce IC, but a relationship between type I interferons and IC has not been clarified in the medical literature. Fifty-six primary suspect reports of type I interferons associated with IC in patients with HCV or MS were identified from the FDA AERS. Seventeen cases were reported with IFN-α and 39 cases were reported with IFN-β. The majority of the cases were in females (80%) and those between the ages of 50 and 65 years (52%). The Naranjo probability scale identified 13 probable and 4 possible cases of IFN-α-induced IC, and 19 probable and 20 possible cases of IFN-β-induced IC. In the literature, 11 cases of IFN-α-induced IC were reported, while there were no reports with IFN-β.

CONCLUSIONS

Our study suggests a possible association between treatment with type I interferons and the development of IC. Further research to determine the mechanism of this association is warranted.

A peptide mimotope of hepatitis C virus E2 protein is immunogenic in mice and block human anti-HCV sera

Conformational B-cell epitopes on the HCV E2 protein recognized by human antibodies were characterized by the use of a peptide mimotope named K1. K1 was identified by two HCV anti-E2 monoclonal antibodies (mAbs) following selection and purification of phage clones containing a 15-mer random peptide insert. Murine antisera to the mimotope K1 recognized the E2 protein. Five of eight human sera from patients who had cleared HCV recognized the K1 mimotope. Binding to E2 in four individuals with the capacity to block E2-CD81 interaction was inhibited by the mimotope K1. The results demonstrate that anti-E2 antibodies in sera from patients who have cleared HCV infection are directed against a conformational B-cell epitope on E2 that can be mimicked with linear synthetic peptides. These findings could have implications for vaccine design by employing linear mimotopes to direct B-cell responses against those specific E2 epitopes that may correlate with immunity.

Phase 1b study of pegylated interferon lambda 1 with or without ribavirin in patients with chronic genotype 1 hepatitis C virus infection

Interferon lambda 1 (IFN-lambda1) is a type III IFN that produces intracellular responses similar to those of IFN-alpha but in fewer cell types because of differences in the receptor distribution pattern, and this could potentially result in an improved safety profile. This was an open-label three-part study of patients with chronic hepatitis C virus (HCV) genotype 1 infection. Part 1 evaluated single-agent pegylated interferon lambda (PEG-IFN-lambda) at 1.5 or 3.0 microg/kg administered every 2 weeks or weekly for 4 weeks in patients who had relapsed after previous IFN-alpha-based treatment. Part 2 evaluated weekly doses of PEG-IFN-lambda ranging from 0.5 to 2.25 microg/kg in combination with ribavirin (RBV) for 4 weeks in treatment-relapse patients. Part 3 evaluated weekly PEG-IFN-lambda at 1.5 microg/kg in combination with RBV for 4 weeks in treatment-naive patients. Fifty-six patients were enrolled: 24 patients in part 1, 25 patients in part 2, and 7 patients in part 3. Antiviral activity was observed at all PEG-IFN-lambda dose levels (from 0.5 to 3.0 microg/kg). Two of seven treatment-naive patients (29%) achieved rapid virological response. Treatment was well tolerated with minimal flu-like symptoms and no significant hematologic changes other than RBV-associated decreases in hemoglobin. The most common adverse events were fatigue (29%), nausea (12%), and myalgia (11%). Six patients experienced increases in aminotransferases that met protocol-defined criteria for dose-limiting toxicity (DLT) or temporarily holding therapy with PEG-IFN-lambda. Most DLT occurred in patients with high PEG-IFN-lambda exposure.

CONCLUSION

Weekly PEG-IFN-lambda with or without daily RBV for 4 weeks is well tolerated with minimal adverse events and hematologic effects and is associated with clear antiviral activity across a broad range of doses in patients with chronic HCV.

Pegylated IFN-alpha2b plus ribavirin for treatment-naive patients coinfected with HCV and HIV

Since 1995, after the generalization of highly active antiretroviral therapy (HAART), HCV coinfection in patients with HIV has become a clinical problem of first magnitude. In fact, currently, HCV coinfection is the primary cause of morbi-mortality of AIDS patients in many hospitals. As a consequence, a significant number of clinical trials have been carried out during the past 8-10 years on HCV/HIV-coinfected patients, and have been coincident that the use of pegylated interferon (PEG-IFN) plus ribavirin should be now the gold standard for treating these patients. Various prospective, randomized studies have reached the conclusion that PEG-IFN-alpha(2b) plus ribavirin achieves HCV cure rates in approximately 50% of all patients, together with important clinical consequences, since hepatic illness progression stops or even reverts. Although adverse events are extremely common with this combined treatment, it is also true that their handling by experts means that only 10-15% of patients must abandon treatment.

Hepatitis-C patients have reduced growth hormone (GH) secretion which improves during long-term therapy with pegylated interferon-alpha

OBJECTIVES

In vitro and in vivo data indicate multiple, but contradictory effects of interferon on pituitary hormone secretion. We therefore investigated prospectively basal and stimulated pituitary hormone secretion in 21 patients with chronic hepatitis C virus (HCV) infection before and during antiviral therapy.

METHODS

Twenty-one patients received pegylated interferon-alpha plus either ribavirin or levovirin. Baseline and stimulated growth hormone (GH), cortisol, luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin (PRL), and thyroid-stimulating hormone (TSH) responses were measured using standard pituitary function tests, before therapy in all and during therapy in 17 out of the 21 patients.

RESULTS

Before therapy 17 patients (81%) had severe GH insufficiency and 9 of these had low insulin-like growth factor-1 (IGF-1) concentrations. Basal and stimulated GH concentrations increased significantly during therapy, reducing the number of patients with severe GH insufficiency to four, but IGF-1 remained low. Basal PRL and TSH concentrations were normal before and during therapy, while thyroid-releasing hormone (TRH)-stimulated concentrations increased significantly during therapy. The adrenocorticotropic hormone (ACTH)/cortisol axis, basal and stimulated gonadotropin, and testosterone concentrations were normal throughout. Neither the HCV RNA level nor transaminases correlated with hormone concentrations before or during therapy.

CONCLUSIONS

GH insufficiency is common in patients with chronic HCV infection. While GH secretion improves during antiviral therapy, IGF-1 remains low, indicating persistent GH resistance of hepatocytes. Whether improvement in GH secretion during treatment is due to a direct drug effect or related to the suppression of viral load could not be differentiated, as most patients demonstrated a positive virologic response.

Human combinatorial libraries yield rare antibodies that broadly neutralize hepatitis C virus

One way to dissect the antibody response to an invading microorganism is to clone the antibody repertoire from immune donors and subsequently characterize the specific antibodies. Recently, methodological advances have allowed investigations of neutralizing antibodies against hepatitis C virus (HCV) in vitro. We have investigated three human mAbs, previously isolated from an individual infected with HCV of genotype 2b, that are known to cross-react in a binding assay to the envelope E2 protein of genotypes 1a and 1b. We now report that two of them have a neutralizing activity with a breadth not previously observed. Indeed, mAbs 1:7 and A8 recognized E2 from all of the six major genotypes, and they neutralized retroviral pseudoparticles [HCV pseudoparticles (HCVpp)] carrying genetically equally diverse HCV envelope glycoproteins. Importantly, these antibodies were also able to neutralize the cell culture infectious HCV clone JFH-1 in vitro, with IC(50) values of 60 ng/ml and 560 ng/ml, respectively. The conformational epitopes of these two broadly reactive antibodies were overlapping yet distinct and involved amino acid residues in the 523-535 region of E2, known to be important for the E2-CD81 interaction. The third antibody clone, representing a dominant population in the initial screen for these antibodies, was less broadly reactive and was unable to neutralize the genotype 2a infectious clone JFH-1. Our results confirm at the clonal level that broadly neutralizing human anti-HCV antibodies can be elicited and that the region amino acids 523-535 of the HCV envelope glycoprotein E2 carries neutralizing epitopes conserved across all genotypes.

Interferon-based treatment of chronic hepatitis C

The treatment of patients with chronic hepatitis C has rapidly evolved in the past 10 years centered on the use of interferon alpha 2 as an antiviral and immunomodulatory agent against hepatitis C virus. Firstly used as a monotherapy associated with a deceiving long-term efficacy, interferon alpha was then combined with ribavirin, a nucleoside analog with large antiviral properties. Combination of both drugs dramatically improved the efficacy of treatment with 50% of patients reaching a sustained viral response, characterized by the final eradication of the virus from the infected individual. Surprisingly, this synergistic effect remains greatly unexplained. The third step consisted in the use of pegylated interferon in order to adapt its pharmacokinetics and to allow a better efficacy with a more tolerable dosing schedule: once weekly subcutaneous injection instead of thrice weekly. Pegylated interferon combined with ribavirin during 24-48 weeks of treatment is the current standard of care with nearly 60% of sustained virologic response, overall. Development of new forms of interferon alpha are on the way with promising preliminary results.