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Early Viral Kinetics (early + viral_kinetics)

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Medical Sciences100%

Selected Abstracts

Comparison of adefovir and tenofovir in the treatment of lamivudine-resistant hepatitis B virus infection,

HEPATOLOGY, Issue 6 2004
Florian van Bömmel
Adefovir dipivoxil was recently approved for the treatment of wild-type and lamivudine-resistant hepatitis B virus (HBV) infection. Tenofovir disoproxil fumarate, a congender of adefovir that is used in the treatment of HIV infected patients, has recently been shown to also be effective in patients with lamivudine-resistant HBV infection. We therefore compared the two substances in a study of 53 patients defined by high HBV DNA (>6 log10 copies/mL) levels and genotypic evidence of lamivudine resistance. Thirty-five patients received tenofovir for 72 to 130 weeks, and 18 received adefovir for 60 to 80 weeks. Changes in HBV DNA levels were followed for the complete period of 48 weeks. Early viral kinetics were compared on matched subgroups of 5 patients each. Individually, all tenofovir-treated patients showed a strong and early suppression of HBV DNA within a few weeks whether they were coinfected with HIV or were without comorbidity. In contrast, considerable individual variations in HBV DNA decline were observed in the adefovir group. Thus at week 48, only 44% of these patients had HBV DNA levels below 105 copies/mL in contrast to 100% of the tenofovir-treated patients (P = .001). No severe side effects were noticed in either group. No evidence of phenotypic viral resistance could be demonstrated in the tenofovir-treated patients in the long term (up to 130 weeks). In conclusion, tenofovir may become an effective alternative for the treatment of patients with lamivudine-resistant HBV infection. (HEPATOLOGY 2004;40:1421,1425.) [source]

Comparison of the Bayer VERSANT HCV RNA 3.0 and the Roche COBAS Amplicor HCV Monitor, Version 2.0, assays in HCV genotype 4 infection

JOURNAL OF VIRAL HEPATITIS, Issue 11 2007
W. Jessner
summary Prediction of treatment response is clinically important in chronic hepatitis C virus (HCV) genotype 4 infection. Early viral kinetics is useful in this respect for genotype 1 but interpretation is dependent on assay linearity and reproducibility. The VERSANT HCV RNA 3.0 (bDNA-3.0) and the COBAS Amplicor HCV Monitor 2.0 (HCM-2.0) have been widely used quantitative assays. We wanted to comparatively evaluate the two tests in a large genotype 4 sample. Genotyping was performed by NS5b sequencing. Viral load was tested in parallel in 32 patients at least six times on antiviral therapy with interferon , (IFN,). Totally, 198 samples within a quantitative range from undetectable to about 7 × 106 IU/mL (bDNA-3.0) were obtained and compared. Twenty-two samples with viral load above 500 000 IU/mL tested by HCM-2.0 were 1:100 diluted and retested. Quantitative values were fitted to a third order polynomial (M = 0.118303 + 1.07503 × V+ 0.0112128 × V2 , 0.0055504 × V3; M,HCM-2.0, V,bDNA-3.0, both log IU/mL) showing progressive nonlinearity of HCM-2.0 above 100 000 IU/mL but better clinical sensitivity with respect to bDNA-3.0. Dilution lead to a gain of at least a factor of 2.7 and thus, overestimation compared with bDNA-3.0. Deviation from linearity and overestimation upon dilution by HCM-2.0 are similar with HCV genotype 4, compared with other HCV genotypes. Differences in test performance were not detected for subtypes but for individual patients possibly related to specific quasispecies patterns. The interpretation of viral kinetic data becomes difficult due to overestimation upon dilution of baseline values by HCM-2.0. [source]

Individualized treatment strategy according to early viral kinetics in hepatitis C virus type 1,infected patients,,

HEPATOLOGY, Issue 2 2009
Thomas Berg
Individualized treatment on the basis of early viral kinetics has been discussed to optimize antiviral therapy in chronic hepatitis C virus (HCV) infection. Individually tailored reduction in treatment duration in HCV type 1,infected patients represents one possible strategy. Four hundred thirty-three patients were randomly assigned to receive either 1.5 ,g/kg peginterferon alfa-2b weekly plus 800-1,400 mg ribavirin daily for 48 weeks (n = 225, group A) or an individually tailored treatment duration (18-48 weeks; n = 208, group B). In the latter group, treatment duration was calculated using the time required to induce HCV RNA negativity (branched DNA [bDNA] assay; sensitivity limit, 615 IU/mL) multiplied by the factor 6. All bDNA negative samples were retested with the more sensitive transcription-mediated amplification (TMA) assay (sensitivity limit, 5.3 IU/mL). Sustained virologic response (SVR) rates were significantly lower in group B (34.6% versus 48.0% [P = 0.005]) due to higher relapse rates (32.7% versus 14.2% [P< 0.0005]). Important predictors of response were the levels of baseline viremia as well as the time to TMA negativity on treatment. Taking the simultaneous presence of low baseline viral load (<800,000 IU/mL) and a negative TMA test within the first 4 weeks as predictors for treatment response, SVR rates were comparable between both treatment schedules with an SVR probability of >80% obtained in patients treated for only 18 or 24 weeks. Conclusion: The individualized treatment strategy according to time to bDNA negativity failed to provide comparable efficacy compared with the standard of care. The inferiority of the individualized protocol may be explained by the use of a less sensitive HCV RNA assay, and also by underestimation of the importance of baseline viremia. (HEPATOLOGY 2009.) [source]