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Lamivudine/Adefovir Treatment Increases the Rate of Spontaneous Mutation of Hepatitis B Virus in Patients.

ABSTRACT: The high levels of genetic diversity shown by hepatitis B virus (HBV) are commonly attributed to the low fidelity of its polymerase. However, the rate of spontaneous mutation of human HBV in vivo is currently unknown. Here, based on the evolutionary principle that the population frequency of lethal mutations equals the rate at which they are produced, we have estimated the mutation rate of HBV in vivo by scoring premature stop codons in 621 publicly available, full-length, molecular clone sequences derived from patients. This yielded an estimate of 8.7 × 10-5 spontaneous mutations per nucleotide per cell infection in untreated patients, which should be taken as an upper limit estimate because PCR errors and/or lack of effective lethality may inflate observed mutation frequencies. We found that, in patients undergoing lamivudine/adefovir treatment, the HBV mutation rate was elevated by more than sixfold, revealing a mutagenic effect of this treatment. Genome-wide analysis of single-nucleotide polymorphisms indicated that lamivudine/adefovir treatment increases the fraction of A/T-to-G/C base substitutions, consistent with recent work showing similar effects of lamivudine in cellular DNA. Based on these data, the rate at which HBV produces new genetic variants in treated patients is similar to or even higher than in RNA viruses.

SUBMITTER: Pereira-Gomez M

PROVIDER: S-EPMC5029863 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Lamivudine/Adefovir Treatment Increases the Rate of Spontaneous Mutation of Hepatitis B Virus in Patients.

Pereira-Gómez Marianoel M Bou Juan-Vicente JV Andreu Iván I Sanjuán Rafael R

PloS one 20160920 9

The high levels of genetic diversity shown by hepatitis B virus (HBV) are commonly attributed to the low fidelity of its polymerase. However, the rate of spontaneous mutation of human HBV in vivo is currently unknown. Here, based on the evolutionary principle that the population frequency of lethal mutations equals the rate at which they are produced, we have estimated the mutation rate of HBV in vivo by scoring premature stop codons in 621 publicly available, full-length, molecular clone sequen ...[more]

PMID: 27649318

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Project description:AimTo identify hepatitis B virus polymerase gene mutations during antiviral therapy using lamivudine-adefovir sequential monotherapy followed by lamivudine-adefovir combination therapy.MethodsThe patient cohort included four adult chronic hepatitis B patients who had undergone sequential monotherapy, first with lamivudine (LMV) and then, after developing viral breakthrough, with adefovir (ADV) therapy. All of the patients had non-response or viral breakthrough after LMV-ADV sequential monotherapy, which resulted in the switching of their antiviral regimen to LMV-ADV combination therapy. Eleven serum samples from the four patients who showed non-response to rescue LMV-ADV combination therapy were collected sequentially at a time before the antiviral treatment and then during the LMV monotherapy, ADV monotherapy, and LMV-ADV combination therapy. For the genotypic analysis, the whole 1310-bp polymerase gene region was amplified, cloned and sequenced.ResultsAll patients had been previously treated with 100 mg of LMV once daily for a 15- to 26-mo period. The emergence of resistance mutations to LMV, such as rtM204V/I and/or rtL180M, were found in all patients. Their antiviral regimens were switched to ADV monotherapy as the second line treatment. All patients had viral breakthrough or non-response after the LMV-ADV sequential monotherapy. ADV-resistant mutations were detected after 13 to 19 mo of LMV-ADV sequential monotherapy. The rtA181V/T mutations were predominantly identified during the ADV treatment in the LMV-resistant patients. Twenty-seven of 38 clones were combined with an amino acid change at rt181; three clones had mutations in rt236 and one clone had a combined mutation. The rtA181V/T mutations were not suppressed by the LMV-ADV combination therapy. Thirty-nine of 64 clones showed an rtA181V/T mutation and six clones showed combined mutations in rt181 and rt236. Mutations in rt204 re-emerged during the combination treatment. The rt181 and rt204 mutations did not co-exist in one clone.ConclusionAdd-on lamivudine therapy with adefovir for adefovir resistance may not suppress the pre-existing adefovir-resistant mutation that develops during lamivudine-adefovir sequential monotherapy.

Project description:PURPOSE: This study aimed to clarify the long-term efficacy of the lamivudine treatment in Japanese patients with chronic hepatitis B either with or without lamivudine resistance or with or without adefovir add-on treatment. METHODS: We followed 110 patients who received lamivudine for more than 12 months, including 67 hepatitis B e antigen (HBeAg)-positive and 43 HBeAg-negative patients. RESULTS: The median follow-up after the onset of lamivudine was 48 (range = 12-86) months. In all the patients with or without lamivudine resistance, the level of alanine aminotransferase (ALT) normalization decreased from 70.0% at 1 year to 36.4% at 5 years and the loss of serum HBV DNA level decreased from 72.7% at 1 year to 31.8% at 5 years. Sixty patients (54.6%) developed a lamivudine-resistant mutation, and this occurrence was more frequently observed in those who were HBeAg-positive (P < 0.01), those with a low level of ALT (P < 0.05), and those with a high level of serum HBV DNA (P < 0.01). Thirty-six of 60 patients received adefovir in addition to lamivudine to treat breakthrough hepatitis. A Cox proportional hazards model analysis revealed the level of baseline HBV DNA to be the best predictive factor for the virus recrudescence (risk ratio = 0.466, 95% confidence interval [CI]: 0.246-0.842, P = 0.011) and the breakthrough hepatitis (risk ratio = 0.444, 95% CI: 0.218-0.879, P = 0.019). We carefully monitored the efficacy of this treatment both in patients who received adefovir and in those who did not since the beginning of the lamivudine treatment. The normalization level of ALT was 61.4% at 5 years and the loss of serum HBV DNA was 61.4% at 5 years since lamivudine was started. A histologic improvement was observed in patients with ALT levels less than two times the upper limit of normal at the time of a second liver biopsy. CONCLUSIONS: Although the efficacy of lamivudine is limited because of breakthrough hepatitis, adefovir was used as a salvage treatment of patients with lamivudine-resistant chronic hepatitis B. In addition, lamivudine was used for the treatment of Japanese patients with chronic hepatitis B with or without lamivudine resistance, and was found to be useful regarding the long-term virologic and biochemical responses.

Project description:BackgroundThe efficacy of switching to tenofovir disoproxil fumarate (TDF) monotherapy from lamivudine (LAM) plus adefovir dipivoxil (ADV) combination therapy (stable switching) in patients with LAM-resistant chronic hepatitis B (CHB) and undetectable hepatitis B virus (HBV) DNA is not clear.MethodsIn this non-inferiority trial, patients with LAM-resistant CHB and undetectable serum HBV DNA (<20 IU/mL) for >6 months after initiating LAM+ADV combination therapy were randomized (1:2) either to continue the combination therapy (LAM+ADV group, n = 58) or switched to TDF monotherapy (TDF group, n = 111). They were followed-up with serum biochemistry tests and HBV DNA measurement at 12-week intervals for 96 weeks. The primary endpoint of this study was the proportion of patients with viral reactivation at week 96.ResultsPatients with CHB enrolled in this study (n = 169) included 74 patients with compensated liver cirrhosis. In total, 9 patients (4 in the LAM+ADV group and 5 in the TDF group) dropped-out from the study. After a mean follow-up period of 96 weeks, the proportion of HBV reactivation observed was 6.8% (4/58) in the LAM+ADV group and 4.5% (5/111) in the TDF group by using intention-to-treat analysis (difference, -2.3%; 95% CI, -9.84-5.24%). None of the subjects in either group experienced viral reactivation based on per protocol analysis. No serious adverse reactions were observed. In the subgroup analysis for estimated glomerular filtration rate (eGFR) before and after treatment, decreased eGFR was observed only in the TDF group with cirrhosis (85.22 vs. 79.83 mL/min/1.73 m2, p = 0.000).ConclusionsStable switching to TDF monotherapy yielded non-inferior results at 96 weeks compared to the results obtained with LAM+ADV combination therapy in patients with LAM-resistant CHB and undetectable HBV DNA. However, TDF monotherapy in patients with cirrhosis requires close attention with respect to renal function.Trial registrationClinicalTrials.gov NCT01732367.

Dataset Information

Lamivudine/Adefovir Treatment Increases the Rate of Spontaneous Mutation of Hepatitis B Virus in Patients.

Publications

Lamivudine/Adefovir Treatment Increases the Rate of Spontaneous Mutation of Hepatitis B Virus in Patients.

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