An open-label study of tenofovir in HIV-1 and Hepatitis B virus co-infected individuals.
ABSTRACT Tenofovir is a novel nucleotide analogue recommended for use in HIV-1 infected treatment-experienced patients. Recent data suggest an effect on Hepatitis B virus (HBV) replication. We therefore investigated the use of tenofovir in HIV-1 and HBV co-infected individuals.
Twenty HIV-1/HBV co-infected patients with a median of 108 weeks lamivudine experience (range, 0-270 weeks) received tenofovir 245 mg daily in addition to or as part of their combination antiretroviral therapy. Their immunologic parameters and HIV-1 RNA and HBV DNA viral loads were followed over a period of 52 weeks. In addition, their HBV DNA polymerase was sequenced at baseline to measure the frequency of YMDD mutations that are associated with lamivudine resistance.
A significant decrease in HBV DNA viral load (4 x log ) and alanine aminotransferase levels was observed. There were no significant overall differences between the lamivudine-experienced (n = 15) and -naive (n = 5) individuals and tenofovir was well tolerated. Five patients (25%) underwent HBe antigen seroconversion during the study period. Out of the 15 lamivudine-experienced individuals, 10 had YMDD mutations and one had YIDD mutations in HBV DNA.
These results indicate that 52 weeks of tenofovir in addition to antiretroviral therapy is active against HBV, and it appears to overcome lamivudine resistance.
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ABSTRACT: Primarily resulting as a spin-off of the search for effective anti-HSV or anti-HIV agents, several compounds have been identified as effective and promising candidate anti-HBV drugs, i.e. famciclovir (penciclovir), BMS-200475, lamivudine (3TC), (-)FTC, L(-)Fd4C, L-FMAU, DAPD (DXG), bis(POM)-PMEA and bis(POC)-PMPA. They all inhibit HBV replication in Hep G2 2.2.15 at concentrations that are well below the cytotoxicity threshold. All these nucleoside analogues require three phosphorylation steps to be active, in their triphosphate form, as inhibitors of the HBV DNA polymerase, except for PMEA (adefovir) and PMPA (tenofovir), which need only two phosphorylation steps, to PMEApp and PMPApp, respectively, to interact as chain terminators with the HBV DNA polymerase reaction. Several of these compounds (for example, famciclovir, lamivudine and adefovir) have proven to be efficacious in the duck and/or woodchuck hepatitis models, and, accordingly, famciclovir, lamivudine and adefovir have also proven to be effective (i.e. in reducing HBV DNA levels) in patients with chronic HBV infection. Yet, famciclovir and lamivudine may lead to the emergence of resistance mutations (i.e. L528M and M552V/I) in the HBV DNA polymerase upon long-term treatment. These penciclovir- and lamivudine-resistant HBV mutants still retain susceptibility to adefovir, which, in turn, has so far not been found to engender resistance mutations in HBV. As has become obvious from the experience with the treatment of HIV infections, future HBV chemotherapy may reside in combination drug therapy so as to achieve the highest possible virus reduction, thereby minimizing the likelihood of drug resistance development.International Journal of Antimicrobial Agents 08/1999; 12(2):81-95. · 4.42 Impact Factor
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ABSTRACT: Better treatments for chronic hepatitis B are needed. Lamivudine, the (-)enantiomer of 3'-thiacytidine, is a potent inhibitor of hepatitis B virus (HBV). In a double-blind trial, we randomly assigned 32 patients with chronic hepatitis B (including 17 who had no response to earlier treatment with interferon) to receive 25, 100, or 300 mg of oral lamivudine daily for 12 weeks. The patients were then followed for 24 additional weeks. All the patients had hepatitis B antigen in serum. Levels of HBV DNA became undetectable (< or = 1.5 pg per milliliter) in 70 percent of the patients who received the 25-mg dose of lamivudine and 100 percent of those treated with the 100-mg or 300-mg dose. In most patients, HBV DNA reappeared after therapy was completed; however, six patients (19 percent), including five who had not responded to interferon, had sustained suppression of HBV DNA accompanied by normalization of alanine aminotransferase levels. Hepatitis B e antigen disappeared in four of these six patients (12 percent), three of whom had had no response to interferon. Levels of HBV DNA fell in all patients, including those who had had high levels at base line or normal alanine aminotransferase levels at base line, but sustained responses were more likely in patients with initially low HBV DNA levels and high alanine aminotransferase levels. During and after therapy, alanine aminotransferase levels at least doubled in five patients (50 percent) given the 25-mg dose and eight patients (36 percent) given the 100-mg or 300-mg dose. Minor adverse events occurred that were not related to the dose, as did transient, asymptomatic elevations of amylase, lipase, and creatine kinase levels. In a preliminary trial, 12 weeks of lamivudine therapy was well tolerated, and daily doses of 100 mg and 300 mg reduced HBV DNA to undetectable levels.New England Journal of Medicine 12/1995; 333(25):1657-61. · 51.66 Impact Factor
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ABSTRACT: The amino acid substitution from methionine to valine or isoleucine at the YMDD (tyrosine, methionine, aspartate, aspartate) motif of the HBV polymerase gene is the main mutation responsible for resistance to lamivudine treatment. Detection of emerging HBV variants by direct sequencing of the HBV genome is excessively time-consuming for studying large numbers of clinical samples. The aim of the study was to analyse the emergence of lamivudine-resistant HBV genotypes by means of restriction fragment length polymorphism (RFLP) of the PCR product generated from a fragment of domain C of the polymerase gene, in clinical samples from patients receiving treatment. The results with this method were compared with those obtained with a direct sequencing technique. In total, 139 serum samples were studied from 37 patients with chronic hepatitis B, obtained at pre-treatment and at 9, 12, 18 and 24 months of treatment. Variants were detected by cleavage of the products of the three PCRs with the following enzymes: FokI (identifies the normal variant, YMDD, and the mutant variant YVDD), SspI (identifies the mutant variant, YIDD) and Alw44I (identifies the variant, YVDD). The digested fragments were separated by electrophoresis in 3% agarose gel. Of the 139 serum samples analysed, the wild-type YMDD sequence was detected in 106 (76%), the YVDD variant in 20 (15%) and the YIDD variant in 13 (9%) cases. The non-mutated variant, YMDD, was detected in all the pre-treatment samples. After 9 months of treatment the mutant variant was detected in four of 37 serum samples analysed (11%) (two YVDD and two YIDD). At 12 months, 12 of the 37 serum samples (32%) showed mutations in the YMDD sequence (seven YVDD and five YIDD). Among the 16 serum samples obtained at 18 months, nine had the YMDD variant (56%) (seven YVDD and two YIDD). At 24 months, variants in the YMDD sequence were detected in eight of the 12 patients treated (66%) (four YVDD and four YIDD). HBV genotypes were confirmed by direct sequencing, with consistent results. In 45% of cases, the emergence of HBV variants was not associated with ALT breakthrough. The PCR-RFLP assay used in this study, in perfect concordance with direct sequencing, is an accurate method for genotyping lamivudine-resistant HBV variants. Since it is a rapid low-cost technique, PCR- RFLP is suitable for large-scale screening of these polymorphisms in clinical samples.Journal of Virological Methods 01/2000; 83(1-2):181-7. · 1.90 Impact Factor