UMLS:C0019163 - FACTA Search

Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019163 (hepatitis B)
38,309 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Type-I Interferons exert antiviral and antiproliferative activities through the binding to a common cell surface receptor comprising two subunits, IFNAR1 and IFNAR2. Human recombinant Interferon-alpha(2a) (IFNalpha(2a)) is a potent drug (Roferon-A) used to treat various cancers and viral diseases including Hepatitis B/C infections. To significantly improve the pharmacological properties of the drug, a pegylated form of IFNalpha(2a) was developed (PEGASYS). This 40 kDa PEG-conjugated IFNalpha(2a) ((40)PEG-IFNalpha(2a)) is obtained by the covalent binding of one 40 kDa branched PEG-polymer to a lysine side-chain of IFNalpha(2a). Here, we report the detailed structural, kinetic, and thermodynamic analysis of the binding to the extracellular domain of the receptor IFNAR2 of (40)PEG-IFNalpha(2a) and its isolated positional isomers modified at K31, K134, K131, K121, K164, and K70, respectively, in comparison with unmodified IFNalpha(2a). Our binding studies, using the surface plasmon resonance technique, show that the pegylation does not abolish the binding to the receptor, but significantly reduces the affinity mainly due to a change of the association rate. The results are supported by modeling and simulation of the binding, using Self-Avoiding-Walk calculations for the polymer conformations. A correlation between the structural parameters and the kinetic and thermodynamic parameters of the binding of the positional isomers could be established. For the Isomer-K31 and -K164, the PEG-polymer attachment point is located in proximity to the binding interface, and the isomers display affinity in the range 150-520 nM in an enthalpy-driven binding process. In contrast for the Isomer-K134, -K131, -K121, and -K70, the PEG-polymer is attached remotely from the binding interface, and the isomers exhibit a higher affinity (32-76 nM) in an entropy-driven binding process. This study constitutes an essential collection of knowledge on which the interaction of (40)PEG-IFNalpha(2a) and its positional isomers with its cellular receptors can be better understood.
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PMID:Structural, kinetic, and thermodynamic analysis of the binding of the 40 kDa PEG-interferon-alpha2a and its individual positional isomers to the extracellular domain of the receptor IFNAR2. 1589 17

We studied viral dynamic parameters in 44 chronic hepatitis B/hepatitis B e antigen (HBeAg)(-) patients treated with pegylated interferon alfa-2b (PEG-IFN) 100 or 200 microg weekly or lamivudine 100 mg daily or the combination of PEG-IFN 100 or 200 microg with lamivudine. Patients receiving PEG-IFN monotherapy exhibited viral load oscillations between weekly injections, which were resolved by the addition of lamivudine. The median pharmacological delay was estimated at 4.1, 5.8, and 1.8 hours in PEG-IFN monotherapy, PEG-IFN 100/200 microg + lamivudine, and lamivudine monotherapy, respectively (P = .44). The median half-life of free virus was 12.7 hours (range, 2.4-69.2 hours). The mean antiviral effectiveness of PEG-IFN 100/200 microg monotherapy was lower than that of lamivudine (82.6% vs. 96.4%; P = .005). The mean effectiveness of PEG-IFN 100 microg + lamivudine and PEG-IFN 200 microg + lamivudine was 92.8% and 94.4%, respectively. The half-life of infected cells ranged from 2.7 to 75 days. The median half-life of infected cells in patients receiving the combination regimens of PEG-IFN and lamivudine was similar to that of lamivudine patients (5.0 days vs. 6.0 days, P = .77). In conclusion, the addition of pegylated interferon alfa-2b in lamivudine treatment was found to neither enhance the potency of blocking HBV production nor the decay rates of infected cells. Supplementary material for this article can be found on the HEPATOLOGY website (http://www.interscience.wiley.com/jpages/0270-9139/suppmat/index.html).
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PMID:A viral kinetic study using pegylated interferon alfa-2b and/or lamivudine in patients with chronic hepatitis B/HBeAg negative. 1596 84

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.
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PMID:Peginterferon-alpha 2a for the treatment of hepatitis B infection. 1601 86

A novel cationic liposome modified with soybean sterylglucoside (SG) and polyethylene glycol-distearoylphosphatidylethanolamine (PEG-DSPE) as a carrier of antisense oligodeoxynucleotide (ODN) for hepatitis B virus (HBV) therapy was constructed. Characteristics of the cationic liposomes modified with SG and PEG (SG/PEG-CL) and their complexes with 15-mer phosphorothioate ODN (SG/PEG-CL-ODN complex) were investigated by incorporation efficiency, morphology, electrophoresis, zeta potentials, and size analysis. Antisense activity of the liposomes and ODN complexes was determined as hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) in HepG2 2.2.15 cells by ELISA. Their tissue and intrahepatic distribution were evaluated following intravenous injection in mice. The complexes gained high incorporation efficiency and intact vesicular structure with mean size at approximately 200 nm. The SG/PEG-CL-ODN complexes enhanced the inhibition of both HBsAg and HBeAg expression in the cultured HepG2 2.2.15 cells relative to free ODN. The uptake of SG/PEG-CL and nonmodified cationic liposomes (CL) was primarily by liver, spleen, and lung. Furthermore, the concentration of SG/PEG-CL was significant higher than that of CL in hepatocytes at 0.5 hr postinjection. The biodistribution of SG/DSPE-CL-ODN complex compare with free ODN showed that liposomes enhanced the accumulation of ODN in the liver and spleen, while decreasing its blood concentration. SG/PEG-CL-mediated ODN transfer to the liver is an effective gene delivery method for cell-specific targeting, which has a potential for gene therapy of HBV infections. SG and PEG-modified cationic liposomes have proven to be an alternative carrier for hepatocyte-selective drug targeting.
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PMID:Characteristics and biodistribution of soybean sterylglucoside and polyethylene glycol-modified cationic liposomes and their complexes with antisense oligodeoxynucleotide. 1625 50

Cirrhosis is the result of chronic inflammation and of the progressive increase of fibrosis. In France, hepatitis C infection is the second cause of cirrhosis after alcohol abuse. The other causes of cirrhosis are: hepatitis B infection, genetic haemochromatosis, autoimmune hepatitis, primary biliary cirrhosis, drug-induced cirrhosis, secondary biliary cirrhosis, Wilson's disease and al-antitrypsin deficiency. Etiological treatment is based upon: abstinence in case of alcoholic cirrhosis, the combination of pegylated interferon alpha (PEG IFN) with ribavirin in case of C viral cirrhosis, the PEG IFN and the nucleoside analogs in case of B viral cause; corticosteroids and immunosuppressive drugs in case of autoimmune cirrhosis; venesections in case of genetic haemochromatosis and stopping the drug in case of drug-induced cirrhosis. The complications of cirrhosis such as ascites, oesophageal varices, bleeding, hepatic encephalopathy and hepatocellular carcinoma mainly explain the high rate of morbidity and mortality. Liver transplantation is the established therapy for decompensated liver disease of any etiology significantly changed the outcome of patients with advanced cirrhosis.
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PMID:[Liver cirrhosis in adults: etiology and specific treatments]. 1625 95

About 10% of the Chinese population are chronic carriers of hepatitis B virus (HBV). Thus, the development of a highly efficient process for the preparation of a vaccine based on a recombinant hepatitis B surface antigen (HBsAg) is very important to the Chinese national immunization program. To this end, the ion exchange chromatography recovery of CHO-HBsAg from a recombinant Chinese hamster ovary cell line was shown to increase from about 55 to 80% by the addition of 1% poly(ethylene glycol) (PEG 10,000) to the mobile phase. Furthermore, based on analysis by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), the intact glycoprotein form of CHO-HBsAg was completely preserved by the addition of PEG. In the absence of PEG the glycoprotein form of CHO-HBsAg was also spread out into the high salt elution fraction. High-performance size-exclusion chromatography with on-line multiangle-laser-light scattering (HPSEC-MALLS) analysis was performed to monitor the status of the CHO-HBsAg aggregate structure assembly, particle size and molecular weight distribution after each purification step, and the results showed further that the presence of PEG facilitated the separation and recovery of intact glycoprotein form of CHO-HBsAg and promoted their assembly to proper virus-like particles, which are both important features and prerequisites of their immunogenicity.
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PMID:Ion-exchange chromatography of hepatitis B virus surface antigen from a recombinant Chinese hamster ovary cell line. 1627 91

The dissociation of virus-like particles of Hepatitis B surface antigen (HBsAg) during the adsorption-desorption on the solid-phase of chromatography is a main challenge for its purification. Herein, poly (ethylene glycol) (PEG) was applied as an additive during the purification of HBsAg from recombinant Chinese hamster ovary (CHO) cell culture to improve the HBsAg recovery and protect its structural assembly. The presence of 1% of PEG10000 in the mobile phase of ion-exchange chromatography (IEC) of DEAE-Sepharose FF column could increase the recovery of HBsAg from about 55% to 80%, with a similar purification (-fold) (about 12) compared with the absence of PEG. Importantly, glycosylated protein forms of HBsAg were reserved well by PEG-accompanied chromatography. Furthermore, size exclusion chromatography-multiangle laser light scattering (SEC-MALLS) analysis was performed on line to monitor the aggregates, particle size and molecular weight distribution of HBsAg. The results demonstrated that the HBsAg particle size and assembly are more homogenous after adding PEG in the mobile phase of IEC than no PEG added in the mobile phase.
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PMID:[Polyethylene glycol-accompanied ion-exchange chromatography to purify recombinant hepatitis B virus surface antigen]. 1646 51

Five agents are currently approved for the treatment of chronic hepatitis B: standard interferon-alpha (IFN-alpha), pegylated interferon-alpha 2a (PEG-IFN-alpha 2a), lamivudine, adefovir and entecavir. Each agent has inherent limitations. IFN and PEG-IFN-alpha 2a are effective in a minority of patients and have frequent side effects that limit their tolerability. The efficacy of lamivudine is limited by the emergence of drug-resistant hepatitis B virus (HBV) mutants, restricting its utility as a long-term therapy. Adefovir is well tolerated and associated with a low incidence of resistance but its antiviral effect is not optimal. Entecavir, which has been recently registered, has a more potent anti-viral effect but its long term efficacy and resistance profile is still not known. These antivirals induce a sustained response after withdrawal of therapy in only a minority of patients and therefore the treatment needs to be indefinitely administered in the majority of patients. After a brief summary of the natural history of chronic hepatitis B in order to understand the indications and the objectives of therapy, this review focuses on treatment of HBeAg-negative chronic hepatitis B with IFN and PEG-IFN-alpha 2a.
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PMID:Medical therapy of patients affected by HBeAg-negative chronic hepatitis B. 1655 4

Hepatitis delta virus (HDV) can cause severe acute and chronic liver disease in patients infected by hepatitis B virus. Interferon alpha at high doses, although poorly efficient, is the only treatment reported to provide some benefit in chronic hepatitis delta. Pegylated interferon alpha (PEG-IFN) has not yet been evaluated. Treatment is usually monitored by the qualitative detection of HDV-RNA in serum. In this study, safety and efficacy of PEG-IFN were assessed in chronic hepatitis delta, and serum HDV-RNA kinetics were determined using quantitative RT-PCR. Fourteen patients with chronic hepatitis delta received subcutaneous PEG-IFN alpha-2b during 12 months (1.5 microg/kg per week). Serum HDV-RNA was quantified at initiation and during the course of therapy, and during the posttreatment follow-up period, which ranged from 6 to 42 months (median 16 months). PEG-IFN alpha-2b was well tolerated, inducing no serious adverse effect. Sustained biochemical response was obtained in 8 patients (57%). At the end of treatment, 8 patients (57%) had achieved virological response (undetectable HDV-RNA). Sustained virological response throughout the posttreatment follow-up period was observed in 6 patients (43%). HDV-RNA kinetics were predictive of the response: after 3 months of PEG-IFN, HDV-RNA levels were significantly lower in the responders than in the nonresponders group (P=.018). After 6 months of therapy, a negative HDV-RNA was predictive of sustained response (P=.021). In conclusion, this preliminary study indicates that PEG-IFN alpha-2b is safe and efficient for treatment of chronic hepatitis delta. The follow-up of HDV-RNA levels during therapy, which allows the differentiation of various profiles of virological responses, improves treatment monitoring.
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PMID:Efficacy of peginterferon alpha-2b in chronic hepatitis delta: relevance of quantitative RT-PCR for follow-up. 1694 4

In the last years there was a continuous improvement in the therapy of hepatitis B virus infection. Meanwhile different therapeutic options are available. Therefore the indication for the different treatment options can be chosen dependent on clinical, biochemical, virological and histological parameters. Therapy with interferon alpha or PEG-interferon alpha should be started if positive prognostic parameters and lack of contraindications are present in a patient. Especially therapy with PEG-interferon alpha in recent studies showed good response rates. As an alternative nucleosides/nucleotides like lamivudine, adefovir or entecavir are available. During lamivudine therapy there is an increased risk for the selection of resistant strains, while the selection of resistant strains is less frequent during the medication of adefovir or entecavir. However at present the end of treatment for all nucleosides/nucleotides--especially in HBeAg negative patients--is not clearly defined. In patients with liver cirrhosis (Child B and C) only nucleos(t)ides should be used. In the future combination therapy for the treatment of chronic HBV infection seems very attractive. However at present combination therapy is not approved yet and therefore these options should only be used in clinical studies. Especially, as it seems possible that synergistic, but also antagonistic effects may exist between different drugs.
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PMID:[Therapy of hepatitis B virus infection]. 1698 82

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