Novel fluoronucleoside analog NCC inhibits lamivudine-resistant hepatitis B virus in a hepatocyte model

ABSTRACT Antiviral drug resistance is the most important factor contributing to treatment failure using nucleos(t)ide analogs such as lamivudine for chronic infection with hepatitis B virus (HBV). Development of a system supporting efficient replication of clinically resistant HBV strains is imperative, and new antiviral drugs are needed urgently to prevent selection of drug-resistant HBV mutants. A novel fluorinated cytidine analog, NCC (N-cyclopropyl-4′-azido-2′-deoxy-2′-fluoro-β-d-cytidine), was recently shown to strongly inhibit human HBV in vitro and in vivo. This study was designed to evaluate the antiviral activity of NCC against lamivudine-resistant HBV. We generated a stable cell line encoding the major pattern of lamivudine-resistant mutations rtL180M/M204V and designated it "HepG2.RL1". Immuno-transmission electron microscopic examination and enzyme-linked immunosorbent assay were used to detect secretion of HBV-specific particles and antigens. Quantification of extracellular DNA and intracellular DNA of HepG2.RL1 cells by quantitative real-time polymerase chain reaction revealed >625-fold and >5556-fold increases in the 50% inhibitory concentration of lamivudine, respectively, compared with that for the wild-type virus. The results showed that NCC inhibited DNA replication and HBeAg production in wild-type or lamivudine-resistant HBV in a dose-dependent manner. In conclusion, screening for antiviral compounds active against lamivudine-resistant HBV can be carried out with relative ease using hepG2.RL1 cells. NCC is a potential antiviral agent against wild-type HBV and clinical lamivudine-resistant HBV and deserves evaluation for the treatment of HBV infection.

Tenofovir disoproxil fumarate monotherapy for nucleos(t)ide analogue-naive and nucleos(t)ide analogue-experienced chronic hepatitis B patients

BACKGROUND/AIMS: This study investigated the antiviral effects of tenofovir disoproxil fumarate (TDF) monotherapy in nucleos(t)ide analogue (NA)-naive and NA-experienced chronic hepatitis B (CHB) patients. METHODS: CHB patients treated with TDF monotherapy (300 mg/day) for > or =12 weeks between December 2012 and July 2014 at a single center were retrospectively enrolled. Clinical, biochemical, and virological parameters were assessed every 12 weeks. RESULTS: In total, 136 patients (median age 49 years, 96 males, 94 HBeAg positive, and 51 with liver cirrhosis) were included. Sixty-two patients were nucleos(t)ide (NA)-naive, and 74 patients had prior NA therapy (NA-exp group), and 31 patients in the NA-exp group had lamivudine (LAM)-resistance (LAM-R group). The baseline serum hepatitis B virus (HBV) DNA level was 4.9+/-2.3 log IU/mL (mean+/-SD), and was higher in the NA-naive group than in the NA-exp and LAM-R groups (5.9+/-2.0 log IU/mL vs 3.9+/-2.0 log IU/mL vs 4.2+/-1.7 log IU/mL, P<0.01). The complete virological response (CVR) rate at week 48 in the NA-naive group (71.4%) did not differ significantly from those in the NA-exp (71.3%) and LAM-R (66.1%) groups. In multivariate analysis, baseline serum HBV DNA was the only predictive factor for a CVR at week 48 (hazard ratio, 0.809; 95% confidence interval, 0.729-0.898), while the CVR rate did not differ with the NA experience. CONCLUSIONS: TDF monotherapy was effective for CHB treatment irrespective of prior NA treatment or LAM resistance. Baseline serum HBV DNA was the independent predictive factor for a CVR.

Rescue therapy with adefovir in decompensated liver cirrhosis patients with lamivudine-resistant hepatitis B virus

BACKGROUND/AIMS: Adefovir dipivoxil (ADV) is a nucleotide analogue that is effective against lamivudine-resistant hepatitis B virus (HBV). The aim of this study was to determine the long-term clinical outcomes after ADV rescue therapy in decompensated patients infected with lamivudine-resistant HBV. METHODS: In total, 128 patients with a decompensated state and lamivudine-resistant HBV were treated with ADV at a dosage of 10 mg/day for a median of 33 months in this multicenter cohort study. RESULTS: Following ADV treatment, 86 (72.3%) of 119 patients experienced a decrease in Child-Pugh score of at least 2 points, and the overall end-stage liver disease score decreased from 16+/-5 to 14+/-10 (mean +/- SD, P or =2 points; P=0.001) and high mortality following ADV rescue therapy (P=0.012). CONCLUSIONS: Three years of ADV treatment was effective and safe in decompensated patients with lamivudine-resistant HBV.

A study on relationship between variation of P gene region and genotyping of Lamivudine-resistant hepatitis B virus / 预防医学

Objective To analyze hepatitis B virus( HBV)genotype and the correlation between variation of P gene region and genotyping of Lamivudine-resistant HBV,in order to provide molecular virology basis for anti-virus individualized treatment to different HBV genotypes. Methods Serum markers and HBV DNA of 187 Lamivudine -resistant chronic HBV patients were detected by ELISA and fluorescent quantitative polymerase chain reaction. Moreover,DNA Star and viral genotyping tool were used. Results Of the 187 cases infected with HBV genotype B and C,51 cases were B gene (27. 27%),134 cases were C gene(71. 66%),and 2 cases were mixed infections(1. 07%). HBeAg levels were significantly different between genotype B and C(P<0. 05). P gene mutation results showed that genotype B dominated by YMDD mutation alone and genotype C dominated by YMDD and rtL180M mutation. Conclusion The main HBV genotype of this study is genotype C,and different genotypes may determine the variation patterns of P region which associated with resistance.

Clinical Outcomes after Discontinuation of Lamivudine in Chronic Hepatitis B Patients with Lamivudine Resistant HBV Mutant / 대한간학회지

BACKGROUND/AIMS: The therapeutic strategies of applying adefovir for treating lamivudine resistant HBV mutants are controversial. Thus, we observed the clinical outcomes after discontinuation of lamivudine to establish the timing to initiate adefovir therapy. METHODS: Fifty chronic hepatitis B (CHB) patients with lamivudine resistant HBV mutants who had received lamivudine for more than 12 months were included in the study. We investigated the clinical outcomes at 6 months after the end of treatment (EOT). We compared the serial clinical outcomes among respective groups based on serum ALT at the EOT and the clinical characteristics of patients with or without acute exacerbation (AE) and the HBeAg loss. We also investigated the predictive parameters of AE and HBeAg loss. RESULTS: Fifteen patients (30%) had experienced AE at 6 months after the EOT. Four patients received antiviral agents because of their hepatic decompensation. Patients with AE had higher serum ALT values and lower HBV DNA titers at EOT compared with those patients without AE. Serum ALT at the EOT was the predictive parameter of AE. Eight patients (21.6%) had newly developed HBeAg loss at 6 months after EOT. The total bilirubin at EOT was the predictive parameter of HBeAg loss. CONCLUSIONS: CHB patients with lamivudine resistant HBV mutants had favorable clinical outcomes at 6 months after EOT. Therefore, we can consider observing the clinical courses after discontinuation of lamivudine and it is not always required to overlap the adefovir for treating lamivudine resistant HBV mutants except for the treatment of patients with a high risk of developing decompensation.

Virus Genotype and Lamivudine Resistant Mutation in Chronic B-Viral Hepatitis and Correlation with Pathologic Findings / 대한진단검사의학회지

BACKGROUND: Despite significant progress in vaccine and therapeutic regimen, hepatitis B virus (HBV) infection remains one of the major diseases. Long-term use of lamivudine can induce the emergence of drug resistance. TRUGENE(TM) HBV Genotyping (Visible Genetics Inc., Ga, USA) is an assay that reports the viral genotype and mutations likely to confer resistance to antiviral therapy. In this study, we analyzed HBV genotype and mutations and correlated them with the histologic grade and stage of the liver disease to provide the useful information about the therapy of chronic liver disease. METHODS: HBV DNA was isolated from 86 patients with HBV-associated chronic liver diseases and analyzed by TRUGENE(TM) HBV Genotyping. Histologic grade and stage were correlated with RESULTS: HBV genotypes of 86 patients were all C (100%). Mutations associated with lamivudine resistance were detected in 10 patients (11.6%) and M204I (YIDD) mutant was the most common. Unknown mutation such as L180F was also detected. Statistical analysis showed that the number of coding changes at HBsAg region was significantly correlated with the lobular activity (P=0.01). CONCLUSIONS: All patients were genotype C and lamivudine resistant mutations were detected in 11.6%. L180F mutation, not known previously, was detected in one case. Number of coding changes at HBsAg region was significantly correlated with the lobular activity. It was considered that follow-up studies about the clinical significance of coding changes in HBsAg are needed, and that a further study such as in vitro transfection is necessary to confirm the possibility of a novel mutation of L180F.

Lamivudine-Resistance in Patients with Chronic Hepatitis B and/or Cirrhosis and Detection of Mutations in YMDD Motif of Hepatitis B Virus Genome / 대한간학회지

BACKGROUND/AIMS: Lamivudine is an antiviral nucleoside analogue effective for the treatment of hepatitis B virus (HBV) infection via the inhibition of DNA polymerase activity. The mutations, however, in YMDD motif, such as YVDD and YIDD, have been found to interfere with the therapeutic efficacy of lamivudine. This study was performed to identify the role of such mutant-type HBV among Korean hepatitis B patients with chronic hepatitis or cirrhosis receiving lamivudine treatment. METHODS: Serum samples were collected from four groups of patients; patients with breakthrough (group I, n = 8); patients who showed no response after the treatment (group II, n = 6); patients who showed good response (group III, n = 6); patients with chronic hepatitis B without any treatment (group IV, n = 4). Mutations were detected by PCR-cloning and automated sequencing. RESULTS: Mutations in YMDD were found in only 4 (50%) in group I and were negative in group II. No mutations could be identified in the serum samples collected before treatment and from groups III and IV. YVDD mutation was found to be associated with two additional mutations, 'L-to-M' in 528th amino acid and 'L-to-V' in 577th amino acid. CONCLUSIONS: Lamivudine resistance appeared in three different patterns: (1) breakthrough related to the mutations in YMDD motif; (2) breakthrough not related to the YMDD mutations; and (3) primary non-responder not related to the YMDD mutations.