Lamivudine does not increase the efficacy of interferon in the treatment of mutant type chronic viral heaptitis B

Combination therapy of interferon and nucleotide/nucleoside analogues for chronic hepatitis B

Chronic hepatitis B is one of the leading causes of cirrhosis and hepatocellular carcinoma globally. At present, seven drugs, including two interferons and five oral nucleos(t)ide analogues (NAs), have been approved for the treatment of chronic hepatitis B. Interferon works by immunomodulation, but is successful in less than a third of treated patients and is a relatively weak antiviral. NAs directly suppress the hepatitis B virus but have limited durability. Based on current data, combination of NA and interferon results in greater viral suppression but does not translate to off-treatment sustained response. Concomitant or sequential treatment also does not make a difference. Combining telbivudine and interferon also runs the risk of severe peripheral neuropathy. On the other hand, interferon switch or additional therapy in patients well controlled with NAs appears to improve the durability of off-treatment response. This article reviews current data on interferon and NA combination and discusses potential future developments.

Levels of hepatitis B virus replicative intermediate in serum samples of chronic hepatitis B patients

Hepatitis B virus (HBV) cccDNA levels is an absolute marker of HBV replication in the liver of HBV infected patients. This study aimed to quantify the HBV cccDNA levels in sera and liver tissue samples of treatment naïve patients with chronic hepatitis B. Eighty one chronic hepatitis B (CHB) treatment naïve patients were enrolled from January 2009 to June 2011. Total HBV DNA and HBV cccDNA levels were quantified using sensitive real time PCR assay. The mean age of recruited patients was 34 ± 11.5 years. Fifty four (66.7%) patients were HBeAg negative. Liver tissue samples were available from 2 HBeAg positive and 21 HBeAg negative CHB patients. The amount of total intrahepatic HBV DNA ranged from 0.09 to 1508.92 copies/cell. The median intrahepatic HBV cccDNA was 0.31 and 0.20 copies/cell in HBeAg positive and HBeAg negative cases, respectively. Serum HBV cccDNA was detectable in 85.2 % HBeAg positive and 48.1% HBeAg negative CHB patients. Median serum HBV cccDNA was 46,000 and 26,350 copies/mL in HBeAg positive and HBeAg negative subjects, respectively. There was a significant positive correlation between the levels of intrahepatic total HBV DNA and intrahepatic HBV cccDNA (r = 0.533, p = 0.009). A positive correlation was also seen between serum HBV cccDNA levels and serum HBV DNA levels (r = 0.871, p < 0.001). It was concluded that serum HBV cccDNA could be detectable in higher proportion of HBeAg positive patients compared to HBeAg negative patients. Moreover, the median level of serum HBV cccDNA was significantly higher in HBeAg positive patients in contrast to HBeAg negative subjects.

Interferon/long-term lamivudine combination therapy in anti-HBe positive chronic hepatitis B patients

BACKGROUND

Monotherapy with a single antiviral agent is insufficient in controlling hepatitis B virus infection in the majority of patients with anti-HBe positive chronic hepatitis B. Interferon/long-term lamivudine combination therapy was evaluated to determine if this strategy would improve treatment efficacy and reduce the emergence of lamivudine resistance.

METHODS

In total, 36 consecutive anti-HBe positive patients were treated with interferon (3 MU subcutaneously three times weekly) and lamivudine (100 mg orally once a day) for 12 months. After completion of the combined treatment, all patients continued to receive lamivudine monotherapy indefinitely.

RESULTS

Overall, 35 patients (97%) showed virological response at 12 months. Four patients (11%) cleared HBsAg and developed anti-HBs. During the follow-up time, after the discontinuation of interferon, of 30 +/- 12 months (range: 7-57 months), 13 patients (36%) exhibited breakthrough infection. The cumulative rates of breakthrough infection at the end of 1, 2, 3 and 4 years of treatment were 0%, 14%, 32%, and 59%, respectively.

CONCLUSIONS

Combination therapy appears to be effective and may also delay the selection of lamivudine-resistant variants. However, controlled trials are definitely warranted to clarify the potential benefits of combination antiviral treatment over monotherapy.

Oligonucleotide chip for detection of Lamivudine-resistant hepatitis B virus

Hepatitis B virus (HBV) is one of the major causes of liver disease worldwide. It is important to conduct antiviral therapy against chronic hepatitis B to minimize the amount of liver damage. Lamivudine has been known to be an effective antiviral agent for the treatment of HBV infection. However, the emergence of viral mutants resistant to lamivudine is the main concern during the treatment of HBV-infected patients. Therefore, the detection of lamivudine-resistant mutants is of clinical importance. We have developed an oligonucleotide chip for the detection of lamivudine-resistant HBV which is rapid and accurate. The oligonucleotide chip consists of quality control probes, negative control probes, and specific oligonucleotide probes for the detection of lamivudine-resistant HBV. The specific probes consist of five probes for the detection of wild-type rtL180, rtM204, and rtV207 sequences and seven probes for the detection of HBV mutations. We tested 123 serum samples from patients with chronic HBV infection who had received lamivudine therapy. Eighty samples contained mutants with YMDD mutations. Among these, 17 contained rtM204V (YVDD), 24 contained rtM204I3 (YIDD3), 3 contained rtM204I2 (YIDD2), and 36 contained mixed types. We compared the results obtained with our oligonucleotide chip with those obtained by PCR-restriction fragment length polymorphism (RFLP) analysis and sequencing. The rate of concordance between the assay with the oligonucleotide chip and PCR-RFLP analysis for detection of the YMDD motif was 96.7%. The rate of concordance between the results obtained with the oligonucleotide chip for the detection of rtL180 and rtV207 and the results obtained by sequencing was 100%. Thus, the oligonucleotide chip is a reliable and useful tool for the detection of antiviral-resistant HBV.

Short-term corticosteroids then lamivudine and plasma exchanges to treat hepatitis B virus-related polyarteritis nodosa

OBJECTIVE

To assess the efficacy and safety of lamivudine, an antiviral agent that strongly inhibits hepatitis B virus (HBV) DNA replication, combined with plasma exchanges after short-term corticosteroids for HBV-related polyartertitis nodosa (PAN).

METHODS

Ten patients (8 men, 2 women, mean +/- SD age 50.4 +/- 14.4 years) with previously untreated HBV-related PAN were included in a multicenter, prospective, observational trial. Oral prednisone (1 mg/kg/day) was given for 1 week, then tapered and withdrawn within 1 week. Then, lamivudine (100 mg/day or less in the case of renal insufficiency) was started for a maximum of 6 months. Plasma exchanges were performed simultaneously and scheduled as follows: 3/week for 3 weeks, 2/week for 2 weeks, then 1/week until hepatitis B e antigen (HBeAg) to anti-HBe antibody (HBeAb) seroconversion was obtained or until 2-3 months of clinical recovery was sustained. The primary trial endpoint was clinical recovery from HBV-PAN at 6 months. The secondary endpoint was loss of detectable serum HBeAg and HBV DNA, and HBeAg to HBeAb seroconversion at 9 months.

RESULTS

One death, attributed to catheter-related septicemia, was recorded. At 6 months, all 9 survivors had achieved clinical recovery and by 9 months, 6 of 9 (66%) had seroconverted.

CONCLUSION

The strategy of short-term steroids followed by lamivudine and plasma exchanges effectively led to recovery from HBV-PAN. Because of its oral administration and good safety profile, lamivudine should henceforth be considered the antiviral agent of choice to treat HBV-related PAN.

Rapid and high throughput detection of HBV YMDD mutants with fluorescence polarization

AIM: To develop a simple and rapid detection of HBV gene variants and prediction of lamivudine-resistance in patients.

METHODS: Initially, plasmids harboring the wild-type or mutant HBV DNA fragments were used in a model system. The technique was then applied to clinical samples for an analysis of YMDD mutations. The sera were extracted from chronic hepatitis patients who had received lamivudine treatment for more than one year. P region gene of HBV was amplified by polymerase chain reaction. The excess primers and dNTPs in PCR products were removed by cleaning-up reagents. Template-directed dye-terminator incorporation reaction was performed and R110 or TAMRA labeled acyclo-terminator was added on the 3’ end of TDI-primer specifically. Fluorescence polarization value was measured with Victor 2 multilabel counter and the genotypes of HBV were analyzed.

RESULTS: The YMDD genotypes in recombined positive plasmid and 56 serum samples of HBV infected patients were analyzed by using our TDI-FP method and the specificity and sensitivity were confirmed by DNA sequencing. Five of 56 serum samples showed YVDD phenotype (9%), including 1 YMDD and YVDD mixed infection. Four of 56 showed YIDD phenotype (7.1%).

CONCLUSION: This is a simple, rapid, low cost and high throughput assay to detect HBV polymerase gene variants and suitable for large-scale screening and prediction of the lamivudine-resistance in clinical samples.

Construction of replication-deficient recombinant adenoviral vector carrying HBV S and C region gene by homologous recombination in bacteria and its expression in vitro

AIM

To construct recombinant adenoviral vector carrying HBV S and C region gene by homologous recombination in bacteria and to detect its expression in vitro.

METHODS

HBV pre-S2/S genes and pre-C/C genes were amplified by PCR and were cloned to adenoviral shuttle plasmid pAdTrack-CMV, respectively. Then the resultant pAd Track-CMV-HBs or pAdTrack-CMV-HBe was cotransfected into BJ5183 bacteria with the plasmid pAdeasy-1. The adenoviral plasmid carrying HBV S and C gene (pAd-HBs and pAd-HBe) was generated with homologous recombination in bacteria and the adenoviruses were produced in 293 cells. Both 293 and Vero cells were infected with adenoviruses and the expression of HBsAg and HBeAg was detected by RT-PCR and ELISA in vitro.

RESULTS

The titer of Ad-HBs and Ad-HBe adenoviruses was up to 5×10¹² pfu/L after proliferation in 293 cells. HBsAg and HBeAg were expressed efficiently in 293 and Vero cells after infection.

CONCLUSION

The recombinant adenoviruses expressing HBsAg or HBeAg were constructed successfully and can be used further in gene therapy of HBV.