Tenofovir disoproxil fumarate: In chronic hepatitis B
ABSTRACT Tenofovir disoproxil fumarate (tenofovir DF) is an orally administered ester prodrug of tenofovir, a nucleotide reverse transcriptase inhibitor that shows potent in vitro activity against both hepatitis B virus (HBV) and HIV-1. As a component of antiretroviral combination therapy regimens, tenofovir DF is well established in the treatment of adults with HIV-1 infection. Tenofovir DF, administered once daily, is also used in the treatment of adults with chronic hepatitis B (CHB) [the main focus of this profile]. In CHB, the efficacy of tenofovir DF against HBV has been evaluated in two large randomized, phase III clinical studies in hepatitis B e antigen (HBeAg)-negative or HBeAg-positive adults, with compensated liver function. The trials (planned duration 8 years) were double-blind for the first 48 weeks; thereafter, patients received open-label tenofovir DF. Results at 48 and 96 weeks are available. In these studies, at week 48, a significantly greater proportion of recipients of tenofovir DF 300 mg once daily than oral adefovir dipivoxil 10 mg once daily achieved a complete response (primary endpoint). A complete response was defined as a reduction from baseline in plasma HBV DNA level to <400 copies/mL and histological improvement (reduction of 2 or more points in Knodell necroinflammatory score without worsening of fibrosis). The efficacy of tenofovir DF in the treatment of CHB was also demonstrated over a 96-week treatment period in both studies. Tenofovir DF was generally well tolerated by adults with CHB in the two phase III trials.
Article: Telbivudine[Show abstract] [Hide abstract]
ABSTRACT: Telbivudine, the unmodified L-enantiomer of the naturally occurring nucleoside D-thymidine, is a potent synthetic nucleoside analogue. It acts as a hepatitis B virus (HBV) polymerase inhibitor and preferentially inhibits HBV second strand (DNA-dependent) compared with first strand (RNA-dependent) DNA synthesis. More telbivudine than lamivudine recipients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B and similar proportions of telbivudine or lamivudine recipients with HBeAg-negative disease achieved a therapeutic response at 52 weeks in the large 2-year GLOBE trial. In a phase III trial in Chinese patients, greater reductions in serum HBV DNA occurred with telbivudine than lamivudine at 52 weeks. Reductions in serum HBV DNA at 24 weeks were greater with telbivudine than adefovir in the 1-year switching trial. A lower residual viral load at 52 weeks was seen in patients who received telbivudine or who switched from adefovir to telbivudine at 24 weeks than in patients receiving adefovir. In the 1-year lamivudine switching trial in patients with serum HBV DNA levels >3 log10 copies/mL despite having received prior treatment with lamivudine for a mean of [almost equal or equal to]7 months, those randomised to telbivudine therapy achieved greater reductions in serum HBV DNA levels at 24 weeks than patients randomised to continue lamivudine therapy. Telbivudine was generally well tolerated and most adverse events were of mild or moderate severity. The incidence of severe ALT flares with telbivudine was half that seen with lamivudine at both 52 and 104 weeks in the GLOBE trial.Drugs 01/2007; 67(13):1917-29. DOI:10.2165/00003495-200767130-00011
Article: Antiviral therapy: quo vadis?Future medicinal chemistry 07/2010; 2(7):1049-53. DOI:10.4155/fmc.10.22
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ABSTRACT: During the next few decades, vaccination against hepatitis B virus (HBV) will dramatically change the epidemiological profile of this worldwide infection especially when Heath Policies encourage including HBV vaccination program for the newborns. However, it is still estimated that more than 2000millions living people have met HBV. Symptomatic hepatitis with jaundice is less frequent than asymptomatic infection; however, as much as 350millions of individuals remain chronically infected by HBV. In these cases, the need for efficient antiviral therapy remains clear when a viral replication is observed to control the risk of progression and the need for liver transplantation, which represents the only end-stage treatment. Indeed, patients having chronic hepatitis B (CHB) can now be successfully treated using nucleos(t)ide analogs (NA) or pegylated interferon (PEG-IFN). Therefore, beside vaccination, prevention of the progression of the disease to cirrhosis and liver decompensation, leading to end-stage liver disease and/or to hepatocellular carcinoma, by inhibiting viral replication seems to represent the best approach to improve survival. At last but not least, co-morbidities and other viral infections, leading also to chronic liver cirrhosis or liver inflammation such as the specific satellite delta virus (HDV), human immunodeficency virus (HIV) and/or hepatitis C (HCV) virus, are able to accelerate the progression and have to be taken in account. Interestingly, in treated infection, the dogma of the irreversibility of the liver fibrosis, when the cirrhosis is constituted, is tumbling down. In this review, we will focus on the clinical, virological and therapeutic aspects of hepatitis B infection in order to expose the proposals to follow-up and treat HBV-infected patients and the prevention of drug-resistant HBV mutants that frequently arise, leading to treatment failure and progression to liver disease.Pathologie Biologie 08/2010; 58(4):245-53. DOI:10.1016/j.patbio.2010.05.002