Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019158 (hepatitis)
 30,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We recently found that phosphatidyl-2',3'-dideoxycytidine (phosphatidyl-ddC) had substantial anti-hepatitis B virus (HBV) activity in vitro compared to 2',3'-dideoxycytidine (ddC) (Hostetler et al. (1994) Antiviral Res. 24, 59-67). Upon administration of liposomal phosphatidyl-ddC to mice, a 40-fold higher drug area under curve was observed in the liver. To evaluate the possibility of using liver-targeted anti-HBV nucleosides to treat woodchuck hepatitis virus, we wanted to find the most potent and selective lipid conjugates. It has been shown that 2',3'-dideoxy-3'-thiacytidine as a racemic mixture of the cis-isomer (cis-(+/-)-BCH-189) has much greater activity against HBV viruses than ddC in vitro. Recently, it was shown that the (-)-beta-L-enantiomer (3TC) is more active and less toxic than the (+)-beta-D-form ((+)-BCH-189). To determine whether phospholipid conjugates of 3TC retain antiviral activity in 2.2.15 cells as demonstrated previously with ddC, we synthesized the 1,2-dipalmitoyl-sn-glycerol-3-phosphate conjugates of (+/-)-BCH-189 and 3TC and assessed their anti-HBV and anti-HIV activities, in vitro. Phosphatidyl-3TC and phosphatidyl-BCH-189 had antiviral activity comparable to the respective free drugs in 2.2.15 cells which chronically produce HBV. In HIV-1-infected human peripheral blood mononuclear cells and HT4-6C cells, phosphatidyl-3TC and phosphatidyl-(+/-)-BCH-189 exhibited significantly lower activity than the corresponding free nucleosides. In view of the documented ability of phosphatidyl-ddC to target drug to the liver, it seems reasonable to expect that phosphatidyl-3TC or phosphatidyl-(+/-)-BCH-189 could be employed to provide greatly enhanced hepatic antiviral activity in HBV infection in vivo.
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PMID:Phosphatidyl-2',3'-dideoxy-3'-thiacytidine: synthesis and antiviral activity in hepatitis B-and HIV-1-infected cells. 858 65

The woodchuck (Marmota monax) has proven to be a suitable animal model for studying hepatitis B virus (HBV) infection owing to similarities in the course of infection between woodchuck hepatitis virus (WHV) in woodchucks and HBV in humans. (-)-beta-L-2',3'-Dideoxy-3'-thiacytidine (3TC; lamivudine) is a nucleoside analog which has demonstrated antiviral activity against HBV as well as human immunodeficiency virus (HIV). The purpose of the present investigation was to characterize the pharmacokinetics of 3TC following intravenous and oral administration of 20 mg of 3TC per kg of body weight to woodchucks. Following intravenous administration, the concentrations of 3TC in plasma declined, with a terminal half-life of 2.84 +/- 0.85 h (mean +/- standard deviation). The systemic clearance and steady-state volume of distribution of 3TC were 0.22 +/- 0.078 liters/h/kg and 0.75 +/- 0.13 liters/kg, respectively. The renal clearance of the nucleoside analog was 0.063 +/- 0.016 liters/h/kg. The oral bioavailability of 3TC ranged from 18 to 54%. Allometric relationships between pharmacokinetic parameters and body weight developed by Hussey et al. (E.K. Hussey, K.H. Donn, M.J. Daniel, S.T. Hall, A.J. Harker, and G.L. Evans, J. Clin. Pharmacol. 34:975-977, 1994) were augmented by including data from woodchucks, monkeys (S.M. Blaney, M.J. Daniel, A.J. Harker, K. Godwin, and F.M. Balis, Antimicrob. Agents Chemother. 39:2779-2782, 1995), and additional data from rats (P. Rajagopalan, L. Moore, C.K. Chu, R.F. Schinazi, and F.D. Boudinot, submitted for publication). Interspecies scaling of the pharmacokinetic parameters of 3TC demonstrated a good correlation between clearance (0.74 . W0.76 [where W is body weight]; r = 0.93; P < 0.025), apparent volume of distribution (1.62 . W0.81; r = 0.98; P < 0.005), and steady-state volume of distribution (1.09 . W0.94; r = 0.99; P < 0.05) and species body weight. The allometric relationships for clearance and volume of distribution at steady state predicted the observed pharmacokinetic parameters in humans quite well; however, the apparent volume of distribution was underestimated in humans. Thus, the pharmacokinetic data obtained with the woodchuck HBV animal model should be useful for designing clinical trials.
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PMID:Pharmacokinetics of (-)-2'-3'-dideoxy-3'-thiacytidine in woodchucks. 885 86

The short-term effects of stavudine (d4T) plus lamivudine (3TC) were evaluated among 48 human immunodeficiency virus-infected patients for whom zidovudine therapy had failed or who could not tolerate zidovudine. Patients were followed for 8 weeks after initiation of open-label d4T plus 3TC. Four patients discontinued therapy, because of neutropenia (1), hepatitis (1), or neuropathy (2). Reduction in virus load was -0.86 (+0.3 to -3.4) log10 copies/mL and CD4 cell increase was 30 (-100 to +290) cells/mm3. Virologic response was associated with a higher CD4 cell count, no prior exposure to d4T and 3TC, and no previous AIDS-defining illness. Virus load reduction for patients naive to 3TC and d4T was -1.47 (-0.14 to -3.37) log10 copies/mL. Short-term use of d4T plus 3TC is safe, well-tolerated, and associated with virologic and substantial immunologic benefits. Further evaluation of d4T and 3TC in combination is warranted.
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PMID:Stavudine plus lamivudine in advanced human immunodeficiency virus disease: a short-term pilot study. 935 13

The template for synthesis of hepadnaviral RNAs is a covalently closed circular (ccc) DNA located in the nucleus of the infected hepatocyte. Hepatocytes are normally long-lived and nondividing, and antiviral therapies in chronically infected individuals face the problem of eliminating not only the replicative forms of viral DNA found in the cytoplasm but also the cccDNA from the nucleus. Because cccDNA does not replicate semiconservatively, it is not an obvious target for antiviral therapy. However, elimination of cccDNA might be facilitated if its half-life were short in comparison to the generation time of hepatocytes and if new cccDNA formation were effectively blocked. We have therefore measured cccDNA levels in woodchuck hepatocyte cultures following in vitro infection with woodchuck hepatitis virus and treatment with inhibitors of viral DNA synthesis. The viral reverse transcriptase inhibitors lamivudine (3TC) [(-)-beta-L-2',3'-dideoxy-3'-thiacytidine), FTC (5-fluoro-2',3'-dideoxy-3'-thiacytidine) and ddC (2',3'-dideoxycytidine) were added to the cultures beginning at 4 days postinfection. Treatment for up to 36 days with 3TC reduced the amount of cccDNA in the cultures not more than twofold compared to that of an untreated control. Treatment with ddC for 36 days and with FTC for 12 days resulted in effects similar to that of treatment with 3TC. Moreover, the declines in cccDNA appeared to reflect the loss of hepatocytes from the cultures rather than of cccDNA from hepatocytes. These results emphasize the important role of the longevity of the infected hepatocytes in the persistence of an infection.
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PMID:Lack of effect of antiviral therapy in nondividing hepatocyte cultures on the closed circular DNA of woodchuck hepatitis virus. 937 99

Four agents are in clinical development for the treatment of chronic hepatitis B infection. These nucleoside analogs are incorporated into the growing DNA chain and terminate replication. Lamivudine, a cytadine analog that inhibits the synthesis of negative strand DNA from pre-genomic RNA, predictably inhibits replication and improves liver enzymes and histology in infected individuals. Following cessation of treatment, relapse is common, and genetic causes of viral resistance have been described. Other drugs for HBV infection include famciclovir, a guanosine analog that has also shown to suppress replication in immunocompetent as well as in immunocompromised patients; lobucavir, a guanosine analog; and adevfovir, an adenine nucleotide analog. The future of drug therapy against HBV likely includes combination agents with one or more nucleoside/nucleotide analogs and immune stimulants, such as interferon, or therapeutic vaccines. Recent advances in the treatment of HCV have been less impressive. An effective vaccine is greatly needed yet development in the near future is unlikely. Recommendations for therapy of chronic HCV have been proposed following the National Institutes of Health Consensus Conference. Interferon alpha is advised in patients with elevated serum alanine aminotransferases and liver histology demonstrating active hepatitis, regardless of level of pretreatment viremia or infecting genotype. Therapy should be continued for three months, at which time response should be assessed. If a biochemical and/or virological response has been achieved, treatment should be continued for a year. Trials are underway to evaluate interferon in combination with ribavirin. Recent identification of the crystalline structure of the HCV NS3 protease promises development of effective inhibitors of this critical viral enzyme.
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PMID:Hepatitis B and C viruses: molecular identification and targeted antiviral therapies. 954 65

Lamivudine is a nucleoside analogue with efficacy in the suppression of hepatitis B viral (HBV) replication. In a previously reported study, lamivudine was administered to patients with chronic, actively replicating HBV infection who subsequently underwent liver transplantation. Patients became serum HBV DNA-negative in response to lamivudine before transplantation, which was continued in the post-transplant period. Two of four patients surviving the immediate postoperative period developed allograft reinfection 240 and 409 days post-transplant. The strain of the reinfecting virus was analyzed, and a mutation in the YMDD region of the viral polymerase conferring resistance to lamivudine was discovered. The long term follow-up of these two patients is reported. The first patient developed ascites 16.5 months after allograft reinfection. A transjugular liver biopsy performed 18 months after the emergence of the lamivudine-resistant strain revealed cirrhosis and lobular hepatitis without rejection. The gradient between hepatic vein wedged and free pressures was 13 mmHg, consistent with portal hypertension. The second patient, 16 months after allograft reinfection with the lamivudine-resistant strain, is without clinical evidence of portal hypertension, although liver enzymes remain elevated. Both patients were given a trial of famciclovir, which did not significantly suppress HBV viremia. In conclusion, lamivudine-resistant HBV strains with the YMDD mutation may have an aggressive clinical course with rapid progression to cirrhosis. Famciclovir did not appear to be an effective rescue agent in these two patients.
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PMID:Postliver transplant allograft reinfection with a lamivudine-resistant strain of hepatitis B virus: long-term follow-up. 955 7

A 45-year-old HBsAg carrier (HBeAb positive with normal liver function tests) underwent renal transplantation for mesangioproliferative glomerulonephritis. Sixteen months later he developed jaundice. Investigations showed he remained HBeAb positive, but HBV-DNA levels were 99 pg/ml, indicating active replication of a HBV pre-core mutant. He was commenced on lamivudine therapy with a subsequent rapid fall in HBV-DNA levels to 2.8 pg/ml, but liver function tests continued to deteriorate and he developed hepatorenal failure. Liver biopsy showed fibrosing cholestatic hepatitis. He underwent liver transplantation, which was complicated by lactic acidosis. Lamivudine was withdrawn and HBV prophylaxis with HB immunoglobulin was commenced. Unfortunately he died 38 days post-transplant of surgical complications with no evidence of HBV recurrence. We discuss the use of nucleoside analogues in fibrosing cholestatic hepatitis and review the literature.
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PMID:Nucleoside analogue therapy in fibrosing cholestatic hepatitis--a case report in an HBsAg positive renal transplant recipient. 958 65

Hepatitis B viruses establish a chronic, productive, and noncytopathic infection of hepatocytes. Viral products are produced by transcription from multiple copies (5-50) of covalently closed circular (ccc) viral DNA. This cccDNA does not replicate, but can be replaced by DNA precursors that are synthesized in the cytoplasm. The present study was carried out to determine if long-term treatment with an inhibitor of viral DNA synthesis would lead to loss of virus products, including cccDNA, from the liver of woodchucks chronically infected with woodchuck hepatitis virus. Viral DNA synthesis was inhibited with the nucleoside analog, lamivudine (2'-deoxy-3'-thiacytidine). Lamivudine treatment produced a slow but progressive decline in viral titers in serum, to about 0.3% or less of the initial level. However, even after maintenance of drug therapy for 3-12 months, > 95% of the hepatocytes in most animals were still infected. Significant declines in the percentage of infected hepatocytes and of intrahepatic cccDNA levels were observed in only three woodchucks, two in the group receiving lamivudine and one in the placebo control group. Moreover, virus titers eventually rose in woodchucks receiving lamivudine, suggesting that drug-resistant viruses began to spread through the liver starting at least as early as 9-12 months of treatment. Three types of mutation that may be associated with drug resistance were found at this time, in a region upstream of the YMDD motif in the active site of the viral reverse transcriptase. The YMDD motif itself remained unchanged. Not unexpectedly, the lamivudine therapy did not have a impact on development of liver cancer.
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PMID:Lamivudine therapy of WHV-infected woodchucks. 961 64

Fibrosing cholestatic hepatitis is a histological variant of hepatitis B virus infection with a high rate of mortality. We describe a patient who acquired acute hepatitis B virus infection 8 months after renal transplantation. Clinical features of rapidly progressive liver failure, indicated by prolonged prothrombin time (57 seconds) and increased bilirubin (40.4 mg/dL) and ammonia (129 mumol/L) concentrations, were accompanied by an extremely high serum HBV DNA level (2.153 x 10(6) pg/mL). Liver biopsy specimen showed fibrosing cholestatic hepatitis with widespread balloon degeneration of hepatocytes, focal hepatocyte loss, bile stasis, periportal fibrosis, mild lymphocytic infiltration, and strongly positive immunohistochemical staining for hepatitis B surface antigen (HBsAg) and hepatitis B core antigen. Lamivudine therapy suppressed HBV DNA to < 10 pg/mL within 4 weeks, which was followed by gradual recovery of liver function from a state of hepatic precoma. Twenty-four months after the onset of hepatitis, the patient had normal prothrombin time and bilirubin, transaminase, and albumin levels. She remained HBsAg positive and hepatitis B e antigen negative. Renal allograft function was stable, with a creatinine level of 1.52 mg/dL. HBV DNA remained suppressed after 22 months of lamivudine therapy. Our experience shows that fibrosing cholestatic hepatitis and liver failure caused by HBV infection can be successfully treated with lamivudine.
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PMID:Treatment of fibrosing cholestatic hepatitis with lamivudine. 964 74

The risk of severe hepatic damage in patients with chronic hepatitis B virus (HBV) infection is well known; more effective treatments for this infection are needed. Lamivudine is being studied in immunocompetent and immunosuppressed HBV infected patients. We report a patient suffering from chronic replicative HBV infection after allogeneic BMT, who responded to lamivudine therapy. A 24-year-old woman with CML received an allogeneic BMT from her HLA-identical sister in June 1992. Before transplant, her HBV status demonstrated viral contact without active infection (HBsAb+, HBcAb+ IgG, HBeAb+). Four months after BMT mild chronic liver GVHD appeared, requiring immunosuppressive treatment. Antibodies to HBV completely disappeared post-transplant. Acute icteric hepatitis occurred 2 years later, with HBsAg+, high level of HBV-DNA, HBeAg+ and HBcAb IgM+. Lamivudine 100 mg/day rapidly reduced transaminase levels and effected HBV-DNA disappearance within 2 months. The treatment was well tolerated; no hematological side-effects occurred. This preliminary observation warrants further investigation of lamivudine treatment in bone marrow transplanted patients with active HBV infection.
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PMID:Lamivudine treatment for chronic replicative hepatitis B virus infection after allogeneic bone marrow transplantation. 967 62


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