Peginterferon for the treatment of chronic hepatitis B in the era of nucleos(t)ide analogues

A real-world retrospective single-centre study of the cost-effectiveness and long-term outcomes of pegylated interferon for chronic hepatitis B

Background

Pegylated interferon (Peg-IFN) is recommended as first-line therapy for chronic hepatitis B (CHB) but has significant side effects and is rarely used compared to oral nucleos(t)ide analogues (NA). There are limited recent clinical efficacy or economic analysis data comparing approved CHB therapy in North America.

Methods

This retrospective study examined clinical outcomes, off-treatment durability, and cost-effectiveness of Peg-IFN versus NA for CHB. Demographic (age, sex, ethnicity), clinical data (i.e., liver tests, hepatitis B virus DNA, serology, transient elastography) and documented side effects were collected by retrospective chart review of patients followed in the University of Calgary Liver Unit who received Peg-IFN therapy from January 2007 to December 2020. The cost-effectiveness of Peg-IFN versus NA therapy was modelled over a 10-year time horizon.

Results

Sixty-eight CHB patients were treated with Peg-IFN (median age 45.65, 74% male, 84% Asian); 50/68 (74%) completed 48 weeks of treatment with a median follow-up of 6.54 years (interquartile range 5.07). At the last known follow-up, 23/68 (34%) have not required NA treatment and one had HBsAg loss; 27 have been started on NA. Predictors of obtaining a sustained virological response included being hepatitis B e antigen-negative at treatment end and a quantitative hepatitis B surface antigen <1000 IU/mL. Economic modelling showed that finite Peg-IFN was not cost-effective versus NA at a 10-year time horizon.

Conclusions

PEG-IFN remains a potential treatment for CHB although there is a significant intolerance/failure rate. Using PEG-IFN based on patient preference is reasonable and optimal patient selection may improve treatment cost-effectiveness.

Can G-quadruplex become a promising target in HBV therapy?

The chronic infection with hepatitis B virus (HBV) is an important health problem that affects millions of people worldwide. Current therapies for HBV always suffer from a poor response rate, common side effects, and the need for lifelong treatment. Novel therapeutic targets are expected. Interestingly, non-canonical structures of nucleic acids play crucial roles in the regulation of gene expression. Especially the formation of G-quadruplexes (G4s) in G-rich strands has been demonstrated to affect many bioprocesses including replication, transcription, and translation, showing great potential as targets in anticancer and antiviral therapies. In this review, we summarize recent antiviral studies about G4s and discuss the potential roles of G4 structures in antiviral therapy for HBV.

A Prospective Five-Year Follow-up After peg-Interferon Plus Nucleotide Analogue Treatment or no Treatment in HBeAg Negative Chronic Hepatitis B Patients

BACKGROUND

Currently available treatment options for chronic hepatitis B (CHB) are not recommended for HBeAg-negative patients with a low viral load. These patients may however benefit from treatment by achieving a functional cure, defined by HBsAg-loss and undetectable HBV DNA. This study evaluated the long-term effect of combination treatment with peg-interferon-alpha-2a (peg-IFN) and adefovir or tenofovir compared to no treatment in these patients.

METHODS

HBeAg-negative CHB patients with HBV-DNA levels < 20,000 IU/mL (n = 151) were previously randomised 1:1:1 for peg-IFN 180 μg/week plus either adefovir 10 mg/day or tenofovir 245 mg/day, or no treatment and treated for 48 weeks in an open-label study. In this prospective long-term follow-up study, patients were monitored yearly up to five years after end of treatment (week 308). The primary outcome was sustained HBsAg-loss and secondary outcome the dynamics of HBsAg and HBV-DNA levels over time.

RESULTS

Of the 131 followed patients, the HBsAg-status was known for 118 patients after five-year follow-up. HBsAg-loss occurred similarly (P = 0.703) in all arms: 8/43 (18.6%) peg-IFN + adefovir, 4/34 (11.7%) peg-IFN + tenofovir, and 6/41 (14.6%) among the untreated patients. The time to HBsAg-loss did not differ between groups (P = 0.641). Low baseline HBsAg levels and genotype A were independently associated with HBsAg-loss irrespective of allocation. HBsAg and HBV-DNA levels declined similarly during follow-up in all patient groups.

CONCLUSIONS

This prospective randomised controlled study showed that HBsAg-loss overtime was not influenced by treatment with a combination of nucleotide analogue and Peg-IFN. Low baseline HBsAg levels can predict HBsAg-loss irrespective of treatment allocation.

Hepatitis B core related antigen in relation to intrahepatic and circulating viral markers, before and after combination therapy

INTRODUCTION AND OBJECTIVES

Covalently closed circular (ccc)DNA acts as a viral reservoir in the liver of patients with a chronic hepatitis B (CHB) infection and can only be quantified in liver biopsies. Hepatitis B core-related antigen (HBcrAg) levels in plasma/serum have been proposed to reflect intrahepatic cccDNA-levels and may therefore monitor treatment efficacy. This study aimed to validate the relationship between HBcrAg and other intrahepatic and circulating viral markers in CHB patients with high viral load, before and after combination treatment.

MATERIALS AND METHODS

Plasma/serum levels of HBcrAg, HBsAg, HBV-DNA, and HBV pregenomic RNA (HBV-pgRNA), and intrahepatic cccDNA and HBV-DNA levels and fibrosis scores were measured in 89 CHB patients with HBV-DNA levels of >100,000 copies/mL (17,182 IU/mL). Measurements were done before and after a 48-week treatment with pegylated interferon alfa-2a and adefovir in a prospective study (ISRCTN77073364).

RESULTS

Baseline HBcrAg-values correlated strongly with intrahepatic cccDNA (ρ 0.77, p < 0.001), intrahepatic HBV-DNA (ρ 0.73, p < 0.001) and plasma/serum HBV-DNA (ρ 0.80, p < 0.001), HBV-pgRNA (ρ 0.80, p < 0.001), and to lesser extend HBsAg (ρ 0.56, p < 0.001). Baseline HBcrAg-levels could not predict functional cure (FC) but HBcrAg-levels declined more strongly in patients who developed FC or HBeAg-loss. Furthermore, most correlations persisted at the end of treatment and follow-up.

CONCLUSIONS

HBcrAg reflects cccDNA transcription activity more accurately than HBsAg and may replace HBV-DNA as a marker during future treatment regimens, especially when cccDNA transcription is targeted or nucleot(s)ide analogues are included in the treatment regime.

High Dose of Pegylated Interferon for the Treatment of Chronic Hepatitis B in Children Infected With Genotype C

Chronic hepatitis B virus (HBV) genotype C infection is unlikely to show a good response to interferon (IFN). However, it is unknown whether a high dose of pegylated IFN (PEG-IFN) treatment would be effective for hepatitis B e antigen (HBeAg)-positive children with chronic HBV genotype C infection.

Methods

HBeAg-positive children and adolescents with chronic HBV genotype C infection were eligible for this study. To increase the dose of PEG-IFN, all patients received PEG-IFN-α-2a (180 μg) without dose adjustment on the basis of body surface area for 48 weeks and were followed up for 24 weeks after the completion of treatment.

Results

Thirteen patients (median age, 9 years) were enrolled prospectively for this study. One patient dropped out, and the remaining 12 patients were evaluated. Of the 12 patients, 11 received PEG-IFN of 180 μg/1.73 m² or more (median, 287 μg/1.73 m²). Eight (67%) experienced HBeAg seroconversion, and 1 (8%) achieved hepatitis B surface antigen (HBsAg) loss at the end of follow-up. There was a significant difference in the decrease of hepatitis B surface antigen levels from the baseline to week 24 of treatment between the responders and the nonresponders. Serum cytokines and chemokines were measured in 10 patients. The levels of C-X-C motif chemokine ligand 9, 10, 11, and 13 in the responders tended to be higher than those in the nonresponders during the first 24 weeks of treatment.

Conclusions

A high dose of PEG-IFN treatment was effective and safe. A decrease in the hepatitis B surface antigen level from baseline to week 24 of treatment might be a predictor of HBeAg seroconversion.

Targeting Host Innate and Adaptive Immunity to Achieve the Functional Cure of Chronic Hepatitis B

Despite the availability of an effective preventive vaccine for hepatitis B virus (HBV) for over 38 years, chronic HBV (CHB) infection remains a global health burden with around 257 million patients. The ideal treatment goal for CHB infection would be to achieve complete cure; however, current therapies such as peg-interferon and nucleos(t)ide analogs are unable to achieve the functional cure, the newly set target for HBV chronic infection. Considering the fact functional cure has been accepted as an endpoint in the treatment of chronic hepatitis B by scientific committee, the development of alternative therapeutic strategies is urgently needed to functionally cure CHB infection. A promising target for future therapeutic strategies is immune modulation to restore dysfunctional HBV-specific immunity. In this review, we provide an overview of the progress in alternative therapeutic strategies, including immune-based therapeutic approaches that enhance host innate and adaptive immunity to achieve and increase the functional cure from CHB infection.

Guidance for design and endpoints of clinical trials in chronic hepatitis B - Report from the 2019 EASL-AASLD HBV Treatment Endpoints Conference‡

Representatives from academia, industry, regulatory agencies, and patient groups convened in March 2019 with the primary goal of developing agreement on chronic HBV treatment endpoints to guide clinical trials aiming to 'cure' HBV. Agreement among the conference participants was reached on some key points. 'Functional' but not sterilising cure is achievable and should be defined as sustained HBsAg loss in addition to undetectable HBV DNA 6 months post-treatment. The primary endpoint of phase III trials should be functional cure; HBsAg loss in ≥30% of patients was suggested as an acceptable rate of response in these trials. Sustained virologic suppression (undetectable serum HBV DNA) without HBsAg loss 6 months after discontinuation of treatment would be an intermediate goal. Demonstrated validity for the prediction of sustained HBsAg loss was considered the most appropriate criterion for the approval of new HBV assays to determine efficacy endpoints. Clinical trials aimed at HBV functional cure should initially focus on patients with HBeAg-positive or negative chronic hepatitis, who are treatment-naïve or virally suppressed on nucleos(t)ide analogues. A hepatitis flare associated with an increase in bilirubin or international normalised ratio should prompt temporary or permanent cessation of an investigational treatment. New treatments must be as safe as existing nucleos(t)ide analogues. The primary endpoint for phase III trials for HDV coinfection should be undetectable serum HDV RNA 6 months after stopping treatment. On treatment HDV RNA suppression associated with normalisation of alanine aminotransferase is considered an intermediate goal. In conclusion, regarding HBV 'functional cure', the primary goal is sustained HBsAg loss with undetectable HBV DNA after completion of treatment and the intermediate goal is sustained undetectable HBV DNA without HBsAg loss after stopping treatment.

Guidance for design and endpoints of clinical trials in chronic hepatitis B - Report from the 2019 EASL-AASLD HBV Treatment Endpoints Conference

Representatives from academia, industry, regulatory agencies, and patient groups convened in March 2019 with the primary goal of developing agreement on chronic hepatitis B virus (HBV) treatment endpoints to guide clinical trials aiming to 'cure' HBV. Agreement among the conference participants was reached on some key points. 'Functional' but not sterilizing cure is achievable and should be defined as sustained HBsAg loss in addition to undetectable HBV DNA 6 months post-treatment. The primary endpoint of phase 3 trials should be functional cure; HBsAg loss in ≥30% of patients was suggested as an acceptable rate of response in these trials. Sustained virologic suppression (undetectable serum HBV DNA) without HBsAg loss, 6 months after discontinuation of treatment would be an intermediate goal. Demonstrated validity in predicting sustained HBsAg loss was considered the most appropriate criterion for the approval of new HBV assays to determine efficacy endpoints. Clinical trials aimed at HBV functional cure should initially focus on patients with HBeAg-positive and HBeAg-negative chronic hepatitis, treatment-naïve or virally suppressed on nucleos(t)ide analogues. A hepatitis flare associated with increase in bilirubin or INR should prompt temporary or permanent cessation of investigational treatment. New treatments must be as safe as existing nucleos(t)ide analogues. The primary endpoint for phase 3 trials for hepatitis D virus (HDV) co-infection should be undetectable serum HDV RNA 6 months after stopping treatment. On treatment HDV RNA suppression associated with normalization of ALT is considered an intermediate goal. CONCLUSION: For HBV 'functional cure', sustained HBsAg loss with undetectable HBV DNA after completion of treatment is the primary goal and sustained undetectable HBV DNA without HBsAg loss after stopping treatment an intermediate goal.

Pharmacokinetics and pharmacodynamics of pegylated interferon for the treatment of hepatitis B

Introduction: Interferon (IFN) had both antiviral and immunomodulatory effects, and was one of the approved treatments for hepatitis B virus (HBV). Herein, we reviewed the pharmacokinetics and pharmacodynamics of pegylated IFN-α (PegIFN-α) for the treatment of HBV. Areas covered: The steady-state serum levels of PegIFN-α were reached within 5 to 8 weeks, and the week 48 mean trough concentrations were approximately 2-fold higher than week 1. There was also no difference of the pharmacokinetics in male or female, healthy volunteers or patients with hepatitis B or C infection. PegIFN-α did not affect the metabolism of the cytochrome P450 (CYP) isozymes, except inhibition of CYP1A2. There was also no pharmacokinetic interaction between PegIFN-α and HBV nucleot(s)ide analogues (NUCs). Forty-eight weeks of PegIFN-α achieved 32% of HBeAg seroconversion, 32-43% of HBV DNA suppression, 41-59% of ALT normalization, and 3% of HBsAg seroconversion rate with a post-treatment durable response up to 80% in the initial responders. Expert opinion: On-treatment HBsAg titer guided the treatment of HBV with PegIFN-α. The recommendation of PegIFN-α and NUC combination or switch remained controversial. New immunotherapeutic agents are now in development. Although, PegIFN-α should continue to play a role in the treatment of HBV.

Serum miRNAs Predicting Sustained HBs Antigen Reduction 48 Weeks after Pegylated Interferon Therapy in HBe Antigen-Negative Patients

The therapeutic goal for hepatitis B virus (HBV) infection is HBs antigen (HBsAg) seroclearance, which is achieved through 48-week pegylated interferon (Peg-IFN) therapy. This study aimed to identify predictive biomarkers for sustained HBsAg reduction by analyzing serum microRNAs. Twenty-two consecutive chronic HBV infection patients negative for HBe antigen (HBeAg) with HBV-DNA levels <5 log copies/mL, alanine aminotransferase (ALT) <100 U/L, and compensated liver functions, were enrolled. The patients were subcutaneously injected with Peg-IFNα-2a weekly for 48 weeks (treatment period), followed by the 48-week observation period. HBsAg 1-log drop relative to baseline levels recorded at the end of the observation period was considered effective. Sera were obtained at weeks 0 and 24 during the treatment period analyzed for microRNAs. The microRNA (miRNA) antiviral activity was evaluated in vitro using Huh7/sodium taurocholate cotransporting polypeptide (NTCP) cells. As a result, six patients achieved the HBsAg 1-log drop after the observation periods. Comparison of serum microRNA levels demonstrated that high miR-6126 levels at week 24 predicted HBsAg 1-log drop. Furthermore, miR-6126 reduced HBsAg in culture medium supernatants and intracellular HBV-DNA quantities in Huh7/NTCP cells. In conclusion, high serum miR-6126 levels during Peg-IFN therapy predicted the HBsAg 1-log drop 48 weeks after the completion of therapy. In vitro assays revealed that miR-6126 was able to suppress HBsAg production and HBV replication.

Mechanism of Hepatitis B Virus Persistence in Hepatocytes and Its Carcinogenic Potential

Liver disease associated with persistent infection with hepatitis B virus (HBV) continues to be a major health problem of global impact. Despite the existence of an effective vaccine, at least 240 million people are chronically infected worldwide, and are at risk of developing liver cirrhosis and hepatocellular carcinoma. Although chronic HBV infection is considered the main risk factor for liver cancer development, the molecular mechanisms determining persistence of infection and long-term pathogenesis are not fully elucidated but appear to be multifactorial. Current therapeutic regimens based on the use of polymerase inhibitors can efficiently suppress viral replication but are unable to eradicate the infection. This is due both to the persistence of the HBV genome, which forms a stable minichromosome, the covalently closed circular DNA (cccDNA), in the nucleus of infected hepatocytes, as well as to the inability of the immune system to efficiently counteract chronic HBV infection. In this regard, the unique replication strategies adopted by HBV and viral protein production also appear to contribute to infection persistence by limiting the effectiveness of innate responses. The availability of improved experimental systems and molecular techniques have started to provide new information about the complex network of interactions that HBV establishes within the hepatocyte and that may contribute to disease progression and tumor development. Thus, this review will mostly focus on events involving the hepatocyte: the only target cell where HBV infection and replication take place.

Sustained immune control in HBeAg-positive patients who switched from entecavir therapy to pegylated interferon-α2a: 1 year follow-up of the OSST study

BACKGROUND

In the OSST study, hepatitis B e antigen (HBeAg)-positive chronic hepatitis B patients who switched from long-term entecavir (ETV) therapy to pegylated interferon-α2a (PEG-IFN-α2a; 40 kDa) achieved higher rates of HBeAg seroconversion and hepatitis B surface antigen (HBsAg) loss than those who continued ETV. Herein we report the sustainability of serological responses during 1 year of untreated follow-up in patients who switched from ETV to PEG-IFN-α2a therapy.

METHODS

A total of 62 patients who completed 48 weeks of PEG-IFN-α2a therapy were followed-up for 48 weeks off treatment. Primary end points were HBeAg seroconversion and maintenance of HBeAg seroconversion at 48 weeks post-treatment. Secondary end points included HBsAg loss, HBV DNA <1,000 copies/ml and alanine aminotransferase normalization (<1× upper limit of normal).

RESULTS

The HBeAg seroconversion rate increased from 17.7% (11/62) at the end of treatment to 38.7% (24/62) 1 year post-treatment. Sustained HBeAg seroconversion was achieved by 63.6% (7/11) patients with end-of-treatment responses, while late HBeAg seroconversion was achieved by 33.3% (17/51) of patients who did not have end-of-treatment responses. Sustained HBsAg loss was documented in 6 of 7 patients, and sustained HBV DNA suppression was achieved in 60% (27/45) of patients with an end-of-treatment response.

CONCLUSIONS

In patients who do not achieve HBeAg seroconversion during long-term ETV therapy, switching to finite treatment with PEG-IFN-α2a produces HBeAg seroconversion in a substantial proportion of patients at end of treatment and during 1 year of follow-up. Moreover, HBeAg seroconversion and HBsAg loss are sustained in most patients during 1 year of untreated follow-up.

Advances in therapeutics for chronic hepatitis B

Chronic hepatitis B infection remains a major disease burden globally, and leads to high risk of hepatocellular carcinoma development. Current therapies of nucleot(s)ide analogues and interferon alpha treatment remain limited in their efficacy. Several key findings in the hepatitis B virus (HBV) life cycle have led to the development of novel antiviral drugs to inhibit viral replication and persistence. In addition, recent studies on HBV-specific innate and adaptive immune responses have advanced development of immunotherapy to restore immune mediated virus control in chronic hepatitis B patients. In this review, we discuss potential new therapeutic strategies targeting HBV or the host immune system that might lead to a sustained cure for chronic hepatitis B.

Targeting the Achilles heel of the hepatitis B virus: a review of current treatments against covalently closed circular DNA

Chronic infection with hepatitis B virus (HBV) often leads to the development of liver cancer and cirrhosis, creating immense sociological, clinical and economic burdens worldwide. Although current anti-HBV medications manage to control the disease progression and help restore normal liver functions, they often fail to eliminate the virus completely. A major reason for this failure is the presence of a stable viral genome in the hepatocyte nucleus: the covalently closed circular DNA (cccDNA). Targeting HBV cccDNA is a promising approach that could lead to a complete cure. Here, we review various research approaches that are directed toward eliminating HBV cccDNA. This is a brief, yet comprehensive, summary of current state-of-the-art developments in this emerging area of interest.

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.

Hepatitis B virus surface antigen seroconversion in HIV-infected individual after pegylated interferon-alpha treatment: a case report

Hepatitis B virus (HBV) infects from 6 to 14% of HIV-infected individuals. Concurrent HIV/HBV infection occurs due to the overlapping routes of transmission, particularly sexual and parenteral. HIV-infected patients that have acute hepatitis B have six times greater risk of developing chronic hepatitis B, with higher viral replication, rapid progression to end-stage liver disease and shorter survival. The coinfection is also associated with poor response to hepatitis B treatment with interferon-alpha and increased liver toxicity to the antiretroviral therapy. Herein, we describe the case of a 35-year-old man who engages in sex with men and presented with newly diagnosed HIV-1, serological markers for acute hepatitis B and progression to chronic hepatitis B infection (HBsAg+ > 6 months, high alanine aminotransferase levels and moderate hepatitis as indicated by liver biopsy). Lacking indication of antiretroviral treatment (CD4 768 cells/mm³), he was treated with pegylated-interferon alpha2b (1.5 mg/kg/week) by subcutaneous injection for 48 weeks. Twelve weeks after treatment, the patient presented HBeAg seroconversion to anti-HBe. At the end of 48 weeks, he presented HBsAg seroconversion to anti-HBs. One year after treatment, the patient maintained sustained virological response (undetectable HBV-DNA). The initiation of antiretroviral therapy with nucleosides and nucleotides is recommended earlier for coinfected individuals. However, this report emphasizes that pegylated interferon remains an important therapeutic strategy to be considered for selected patients, in whom the initiation of HAART may be delayed.

Expression of hepatitis B virus 1.3-fold genome plasmid in an SV40 T-antigen-immortalized mouse hepatic cell line

AIM: To investigate the expression of the hepatitis B virus (HBV) 1.3-fold genome plasmid (pHBV1.3) in an immortalized mouse hepatic cell line induced by SV40 T-antigen (SV40T) expression.

METHODS: Mouse hepatic cells were isolated from mouse liver tissue fragments from 3-5 d old Kunming mice by the direct collagenase digestion method and cultured in vitro. The pRSV-T plasmid was transfected into mouse hepatic cells to establish an SV40LT-immortalized mouse hepatic cell line. The SV40LT-immortalized mouse hepatic cells were identified and transfected with the pHBV1.3 plasmid. The levels of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) in the supernatant were determined by an electrochemiluminescence immunoassay at 24, 48, 72 and 96 h after transfection. The expressions of HBsAg and hepatitis B c antigen (HBcAg) in the cells were investigated by indirect immunofluorescence analysis. The presence of HBV DNA replication intermediates in the transfected cells and viral particles in the supernatant of the transfected cell cultures was monitored using the Southern hybridization assay and transmission electronic microscopy, respectively.

RESULTS: The pRSV-T plasmid was used to immortalize mouse hepatocytes and an SV40LT-immortalized mouse hepatic cell line was successfully established. SV40LT-immortalized mouse hepatic cells have the same morphology and growth characteristics as primary mouse hepatic cells can be subcultured and produce albumin and cytokeratin-18 in vitro. Immortalized mouse hepatic cells did not show the characteristics of tumor cells, as alpha-fetoprotein levels were comparable (0.58 ± 0.37 vs 0.61 ± 0.31, P = 0.37). SV40LT-immortalized mouse hepatic cells were then transfected with the pHBV1.3 plasmid, and it was found that the HBV genome replicated in SV40LT-immortalized mouse hepatic cells. The levels of HBsAg and HBeAg continuously increased in the supernatant after the transfection of pHBV1.3, and began to decrease 72 h after transfection. The expressions of HBsAg and HBcAg were observed in the pHBV1.3-transfected cells. HBV DNA replication intermediates were also observed at 72 h after transfection, including relaxed circular DNA, double-stranded DNA and single-stranded DNA. Furthermore, a few 42 nm Dane particles, as well as many 22 nm subviral particles with a spherical or filamentous shape, were detected in the supernatant.

CONCLUSION: SV40T expression can immortalize mouse hepatic cells, and the pHBV1.3-transfected SV40T-immortalized mouse hepatic cell line can be a new in vitro cell model.

The anti-HBV effect mediated by a novel recombinant eukaryotic expression vector for IFN-α

BACKGROUND

Chronic hepatitis B is a primary cause of liver-related death. Interferon alpha (IFN-α) is able to inhibit the replication of hepadnavirus, and the sustained and stable expression of IFN-α at appropriate level may be beneficial to HBV clearance. With the development of molecular cloning technology, gene therapy plays a more and more important role in clinical practice. In light of the findings, an attempt to investigate the anti-HBV effects mediated by a eukaryotic expression plasmid (pSecTagB-IFN-α) in vitro was carried out.

METHODS

HBV positive cell line HepG2.2.15 and its parental cell HepG2 were transfected with pSecTagB-IFN-α or empty plasmid by using Lipofectamine™ 2000 reagent. The expression levels of IFN-α were determined by reverse transcriptase polymerase chain reaction (RT-PCR) and ELISA methods. The effects of pSecTagB-IFN-α on HBV mRNA, DNA and antigens were analyzed by real-time fluorescence quantitative PCR (qRT-PCR) and ELISA assays. RT-PCR, qRT-PCR and western blot were employed to investigate the influence of pSecTagB-IFN-α on IFN-α-induced signal pathway. Furthermore, through qRT-PCR and ELISA assays, the suppressive effects of endogenously expressed IFN-α and the combination with lamivudine on HBV were also examined.

RESULTS

pSecTagB-IFN-α could express efficiently in hepatoma cells, and then inhibited HBV replication, characterized by the decrease of HBV S gene (HBs) and HBV C gene (HBc) mRNA, the reduction of HBV DNA load, and the low contents of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg). Mechanism research showed that the activation of Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signal pathway, the up-regulation of IFN-α-induced antiviral effectors and double-stranded (ds) RNA sensing receptors by delivering pSecTagB-IFN-α, could be responsible for these phenomena. Furthermore, pSecTagB-IFN-α vector revealed effectively anti-HBV effect than exogenously added IFN-α. Moreover, lamivudine combined with endogenously expressed IFN-α exhibited stronger anti-HBV effect than with exogenous IFN-α.

CONCLUSION

Our results showed that endogenously expressed IFN-α can effectively and persistently inhibit HBV replication in HBV infected cells. These observations opened a promising way to design new antiviral genetic engineering drugs based on IFN-α.

Do we need to determine viral genotype in treating chronic hepatitis B?

Many studies have attested that not only does HBV genotype influence the outcome of the disease but it also influences the outcome of therapy with interferons and pegylated interferons, with genotype A doing better than genotype D in Caucasians and genotype B better than genotype C in Asians. However, the guidelines from three regional bodies - AASLD, APASL and EASL - all stop short of recommending genotyping as part of the management of chronic hepatitis B. The recommendations, however, from several national organizations as well as from individual reviewers suggest that genotyping is essential to detect patients in whom the use of pegylated interferon will give a high likelihood of response with a finite course of therapy and avoid the disadvantages of nucleoside analogues with their viral resistance. It is concluded that determination of HBV genotype should form part of the management in treating chronic hepatitis B.

[Viral hepatitis B und C]

Chronic hepatitis B (HBV) and C virus (HCV) infection can lead to liver cirrhosis, hepatocellular carcinoma and death. Treatment of these worldwide prevalent infectious diseases is subject to intensive research efforts with development of new antiviral substances and optimization of treatment strategies using molecular markers. The goal of HBV and HCV treatment is control and elimination of viral replication, respectively, thereby preventing hepatitis-associated complications. While interferon alpha is used less frequently to treat hepatitis B today, it is still (in the pegylated or albumin-fused form) an essential component of hepatitis C therapy. The growing number of targeted therapies such as new nucleus(t)ide analogs, HCV protease and RNA polymerase inhibitors and other new compounds has added complexity to the treatment of viral hepatitis. This update summarizes the current standard of care as well as new developments in chronic hepatitis B and C therapy.