HBsAg seroclearance in Chinese patients receiving lamivudine therapy for chronic hepatitis B virus infection

Incidences and Determinants of Functional Cure during Entecavir or Tenofovir Disoproxil Fumarate for Chronic Hepatitis B

BACKGROUND

Long-term incidences and baseline determinants of functional cure (HBsAg seroclearance) during entecavir (ETV) or tenofovir disoproxil fumarate (TDF) treatment are incompletely understood.

METHODS

This is an international multicenter cohort study of treatment-naïve chronic hepatitis B (CHB) patients who initiated on ETV or TDF without baseline malignancy. Patients were observed for HBsAg seroclearance until death or loss to follow-up. We calculated the incidences and explored the baseline determinants of HBsAg seroclearance using competing risk regression.

RESULTS

The analysis included 4,769 patients (median age, 50 years; 69.05% male), with a median follow-up of 5.16 years (26,614.47 person-years). HBsAg clearance occurred in 58 patients, yielding a 10-year cumulative incidence of 2.11% (95% CI, 1.54 -- 2.88%) and an annual rate of 0.22% (95% CI, 0.17--0.28%). Baseline predictors included low-level viremia with HBV DNA <2,000 IU/mL (adjusted sub-distribution HR [aSHR], 3.14; 95% CI, 1.80--5.49), elevated serum alanine aminotransferase (ALT) >200 U/L (aSHR, 3.68; 95% CI, 2.07--6.53), serum bilirubin (aSHR, 1.11 per mg/dL; 95% CI, 1.06--1.17), and fatty liver (aSHR, 1.84; 95% CI, 1.03--3.29).

CONCLUSION

HBsAg seroclearance rarely occurs in CHB patients treated with ETV or TDF and is associated with low-level viremia, ALT flare, bilirubin level, and fatty liver.

Systematic review of risk factors of hepatocellular carcinoma after hepatitis B surface antigen seroclearance

There is no consensus about factors that increase risk of hepatocellular carcinoma (HCC) among patients with chronic hepatitis B who have achieved seroclearance of hepatitis B surface antigen (HBsAg). To assess the available evidence about risk factors for HCC after HBsAg seroclearance, Scopus, EMBASE, PubMed and Cochrane Library databases were systematically searched for relevant studies published through 15 September 2017. A total of 28 studies involving more than 105 411 patients with chronic hepatitis B were included. HBsAg seroclearance occurred spontaneously in 7656, while it occurred after interferon or nucleos(t)ide analogue therapy in 1248. The rate of HBsAg seroclearance was 6.77%. Incidence of HCC was significantly lower among patients who experienced HBsAg seroclearance than among those who remained HBsAg-positive (1.86% vs 6.56%, P < .001). Risk factors of HCC occurrence included cirrhosis (incidence with vs without: 9.51% vs 1.66%), male gender (2.34% vs 0.64%) and age ≥ 50 year at HBsAg seroclearance (2.34% vs 0.63%) (all P < .001). The available evidence suggests that HCC can develop at a low rate after HBsAg seroclearance, so periodic surveillance is recommended, especially for male patients, patients with cirrhosis and patients who experience HBsAg seroclearance when at least 50 years old.

Development of a digital droplet PCR assay to measure HBV DNA in patients receiving long-term TDF treatment

The COBAS TaqMan assay has a lower limit of quantification (LLOQ) of 169 HBV copies/mL and a lower limit of detection (LLOD) of 58 copies/mL. HBV DNA below the TaqMan LLOQ is classified as target not detected (TND) (<58 copies/mL) or target detected (TD) (between 58 and 169 copies/mL). Here we have developed a more sensitive digital droplet PCR (ddPCR) assay to evaluate the impact of long-term tenofovir disoproxil fumarate (TDF) treatment in patients that did or did not achieve HBsAg seroconversion. A ddPCR assay was developed to detect HBV DNA to 8 copies/mL. HBV DNA levels in plasma from patients with or without HBsAg seroconversion were assessed by ddPCR. For patients who did not achieve HBsAg seroconversion, the majority of TD samples (33/58, 57%) were HBV DNA positive by ddPCR while (10/37, 27%) of TND samples were positive. In contrast, for patients who achieved HBsAg seroconversion, HBV DNA was rarely detected by ddPCR after HBsAg seroconversion (1/28, 3.6%). ddPCR is a sensitive method to evaluate low-level viral replication in plasma samples. Frequent detection of HBV DNA by ddPCR among patients who did not achieve HBsAg seroconversion suggests new agents may be needed to suppress low levels of replicating HBV.

Clinical characteristics and potential aetiologies of non-B non-C hepatocellular carcinoma in hepatitis B virus endemic area

BACKGROUND & AIMS

We investigated potential aetiologies, clinical characteristics and prognosis of non-B non-C (NBNC) hepatocellular carcinoma (HCC) patients in hepatitis B virus (HBV) endemic area, according to potential causes such as previous HBV exposure, chronic alcohol intake and metabolic syndrome.

PATIENTS AND METHODS

Among 4690 HCC patients treated at Asan Medical Center between 2007 and 2009, 523 were newly diagnosed with NBNC HCC, and their medical records and survival data were analyzed retrospectively.

RESULTS

Among 321 NBNC HCC patients whose hepatitis B core antibody (anti-HBc) test results were available, 81.0%, 37.1% and 15.5% had anti-HBc positivity, chronic alcohol intake and metabolic syndrome respectively. One-hundred and fifty-two patients (47.4%) had previous exposure to HBV without chronic alcohol intake or metabolic syndrome. Hepatitis B surface antibody (anti-HBs) was positive in 48.0% of the 523 NBNC HCC patients, which was much lower than that in general Korean population, and 52.3% of anti-HBc-positive NBNC HCC patients were negative for anti-HBs. Anti-HBc-negative alcoholic patients presented with more advanced cirrhosis with Child-Pugh class B/C liver function than anti-HBc-positive patients (P = 0.002). In multivariate analysis, baseline liver function, alpha-foetoprotein levels and tumour stage were significant prognostic factors and aetiology did not affect patient survival.

CONCLUSIONS

Prior HBV infection could be a potential aetiology in over 40% of NBNC HCC patients in HBV endemic area. Positivity for anti-HBc and negativity for anti-HBs may be a serologic surrogate marker for occult HBV infection in these area. The prognosis of NBNC HCC was determined by tumour stage and underlying liver function.

Seroclearance of Hbsag in Chronic Hepatitis B Virus Patients on Lamivudine Therapy: A 10 Year Experience

Introduction:

The aim of this study was to determine hepatitis B surface antigen (HBsAg) seroclearance rate among patients treated with lamivudine at a specialized tertiary care referral hospital in Tehran, Iran.

Methods:

All patients on lamivudine (biovudin®) therapy at a dose of 100 mg/day, who showed seroclearnace between March 2001 and September 2011 were recruited. The main evaluation parameters were duration of HBsAg seroclearance and duration of HBsAg seroconversion. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were evaluated using standard methods. HBsAg seroclearance was defined as two consecutive negative serums HBsAg at least 6 months apart, whereas HBsAg seroconversion was defined as the disappearance of serum HBsAg and the presence of anti-HBs for >6 months.

Results:

A total of 203 chronic HBV patients treated with lamivudine at a dose of 100 mg/day were included in the study. HBsAg seroclearance and seroconversion were observed in 11 patients after the initiation of the lamivudine therapy. Overall, in lamivudine responder patients, the mean time to HBsAg seroclearance was 26.90±10.93 months (range: 12-48 months). Furthermore, the responders showed seroconversion after a mean time of 26.90±11.08 months from the initiation of lamivudine therapy. When comparing the characteristics of those who have responded to lamivudine and those who have not responded, baseline HBV-DNA levels was significantly lower in responder than non responder patients (p<0.001). Meantime, there was no difference in age, sex, baseline ALT, AST and liver biopsy score between lamivudine responder and lamivudine non-responder patients.

Conclusion:

Despite introduction of tenofovir and entecavir as first line treatment for chronic HBV infection, lamivudine remains to be a low cost, safe and effective drug for HBsAg seroclearnace.

Sequence variations of full-length hepatitis B virus genomes in Chinese patients with HBsAg-negative hepatitis B infection

BACKGROUND

The underlying mechanism of HBsAg-negative hepatitis B virus (HBV) infection is notoriously difficult to elucidate because of the extremely low DNA levels which define the condition. We used a highly efficient amplification method to overcome this obstacle and achieved our aim which was to identify specific mutations or sequence variations associated with this entity.

METHODS

A total of 185 sera and 60 liver biopsies from HBsAg-negative, HBV DNA-positive subjects or known chronic hepatitis B (CHB) subjects with HBsAg seroclearance were amplified by rolling circle amplification followed by full-length HBV genome sequencing. Eleven HBsAg-positive CHB subjects were included as controls. The effects of pivotal mutations identified on regulatory regions on promoter activities were analyzed.

RESULTS

22 and 11 full-length HBV genomes were amplified from HBsAg-negative and control subjects respectively. HBV genotype C was the dominant strain. A higher mutation frequency was observed in HBsAg-negative subjects than controls, irrespective of genotype. The nucleotide diversity over the entire HBV genome was significantly higher in HBsAg-negative subjects compared with controls (p = 0.008) and compared with 49 reference sequences from CHB patients (p = 0.025). In addition, HBsAg-negative subjects had significantly higher amino acid substitutions in the four viral genes than controls (all p<0.001). Many mutations were uniquely found in HBsAg-negative subjects, including deletions in promoter regions (13.6%), abolishment of pre-S2/S start codon (18.2%), disruption of pre-S2/S mRNA splicing site (4.5%), nucleotide duplications (9.1%), and missense mutations in "α" determinant region, contributing to defects in HBsAg production.

CONCLUSIONS

These data suggest an accumulation of multiple mutations constraining viral transcriptional activities contribute to HBsAg-negativity in HBV infection.

Nucleoside/nucleotide analogues in the treatment of chronic hepatitis B

The current available agents for the treatment of chronic hepatitis B (CHB) include immunomodulatory agents, such as interferon-α and pegylated interferon-α, and oral nucleoside/nucleotide analogues (NAs), including lamivudine, adefovir, telbivudine, entecavir and tenofovir. The NAs work mainly by inhibiting hepatitis B virus (HBV) DNA polymerase activity and thus suppress HBV replication. Oral NAs have become the mainstay of CHB treatment, mainly due to their profound viral suppressive effects and also due in part to the ease of single daily dosing and lack of significant side effects. One major drawback of NA therapy is the development of drug resistance mutations with long-term treatment. Lamivudine, the first oral NA approved for CHB patients, is associated with high rates of drug resistance, with resultant virological relapse and biochemical flare. Fortunately, newer and more potent NAs, such as entecavir and tenofovir, have very low resistance rates, with potent and durable viral suppression. This review is aimed at the current developments in NAs for CHB treatment, detailing the mechanisms of antiviral activity of the different agents, the efficacy of viral suppression, the achievement of treatment endpoints, the development of drug resistance and the optimal strategies for using these drugs.

Emergence of hepatitis B virus S gene mutants in patients experiencing hepatitis B surface antigen seroconversion after peginterferon therapy

With anti-hepatitis B virus (anti-HBV) therapy using peginterferon, the seroconversion of hepatitis B surface antigen (HBsAg), which is considered a cure of the disease, can be achieved in a small percentage of patients. Eight of 245 consecutive patients (3.27%) with chronic hepatitis B who received peginterferon therapy at our center achieved HBsAg seroclearance. Surprisingly, two of the eight patients remained viremic according to standard HBV DNA assays. The coding regions of the HBV pre-S/S gene, which were derived from serial serum samples, were analyzed. Site-directed mutagenesis experimentation was performed to verify the phenotypic alterations in Huh-7 cells. In patient 1, an sT125A mutant developed during the HBsAg-negative stage and constituted 11.2% of the viral population. The HBV DNA level was 2.73 × 10(4) IU/mL at the time of detection. This mutant was not detectable in the HBsAg-positive stages. A phenotypic study of Huh-7 cells showed a significant reduction of antigenicity. In patient 2, an sW74* truncation mutation was found during the HBsAg-negative stage and constituted 83.1% of the viral population. The HBV DNA level was 4.12 × 10(4) IU/mL at the time of detection. A phenotypic study of Huh-7 cells showed a complete loss of antigenicity. Patient 2 subsequently experienced an episode of hepatitis relapse 7 months after the end of treatment and was negative for HBsAg throughout the hepatitis flare.

CONCLUSION

During antiviral therapy with peginterferon, the achievement of HBsAg seroconversion does not necessarily indicate viral eradication. The emergence of S gene mutants is another possibility, and a relapse with HBsAg-negative hepatitis can occur.

Pathogenesis of occult chronic hepatitis B virus infection

Occult hepatitis B infection (OBI) is characterized by hepatitis B virus (HBV) DNA in serum in the absence of hepatitis B surface antigen (HBsAg) presenting HBsAg-negative and anti-HBc positive serological patterns. Occult HBV status is associated in some cases with mutant viruses undetectable by HBsAg assays; but more frequently it is due to a strong suppression of viral replication and gene expression. OBI is an entity with world-wide diffusion. The failure to detect HBsAg, despite the persistence of the viral DNA, is due in most cases to the strong suppression of viral replication and gene expression that characterizes this “occult” HBV infection; although the mechanisms responsible for suppression of HBV are not well understood. The majority of OBI cases are secondary to overt HBV infection and represent a residual low viremia level suppressed by a strong immune response together with histological derangements which occurred during acute or chronic HBV infection. Much evidence suggests that it can favour the progression of liver fibrosis and the development of hepatocellular carcinoma.

Incidence and determinants of spontaneous hepatitis B surface antigen seroclearance: a community-based follow-up study

BACKGROUND & AIMS

Seroclearance of hepatitis B surface antigen (HBsAg) is one of the most important clinical outcomes for chronic hepatitis B treatment trials. Few studies have explored the incidence and determinants of spontaneous seroclearance using a long-term follow-up study. This study aimed to examine the natural history and predictors of HBsAg seroclearance.

METHODS

A total of 3087 individuals with chronic hepatitis B virus infection were enrolled between 1991 and 1992 in this community-based study. Serum samples collected at baseline and follow-up examinations were tested for HBsAg, hepatitis B e antigen (HBeAg), serum hepatitis B virus (HBV)-DNA levels, and anti-hepatitis C virus serostatus. Cox proportional hazards models were used to estimate HBsAg seroclearance rate ratios associated with various determinants.

RESULTS

HBsAg seroclearance occurred in 562 participants during 24,829 person-years of follow-up evaluation, giving a 2.26% annual seroclearance rate. HBV-DNA levels at baseline and follow-up evaluation were the most significant predictor of seroclearance. Higher HBV viral loads conferred lower HBsAg seroclearance rates (P<.001). A spontaneous decrease in follow-up HBV-DNA level (>or=3 log) was associated significantly with seroclearance, showing an adjusted odds ratio of 4.17 (95% confidence interval, 2.55-6.82). Among those with seroclearance, 95.8% had undetectable HBV-DNA levels before seroclearance. Cumulative incidence of HBsAg seroclearance at 60 and 100 months after serum HBV-DNA level decreased to undetectable was 25.8% and 51.3%, respectively.

CONCLUSIONS

This study reveals determinants of HBsAg seroclearance, and suggests that a low viral load is an important factor affecting the natural seroclearance of HBsAg, indicating significant clinical implications for the treatment of chronic HBV.

Current treatments for patients with HBeAg-positive chronic hepatitis B virus infection: a comparison focusing on HBeAg seroconversion

HBeAg seroconversion, in association with undetectable levels of hepatitis B virus DNA as determined by polymerase chain reaction, is an important goal in the treatment of patients with HBeAg-positive chronic hepatitis B (CHB). Achievement of sustained HBeAg seroconversion at an early age (<40 years) is associated with a reduced incidence of hepatic complications, increased rates of HBsAg loss and seroconversion and improved survival rates, whether the seroconversion is spontaneous or treatment induced. Patients with HBeAg-positive CHB who achieve sustained HBeAg seroconversion and complete 6-12 months of consolidation therapy are eligible for stopping therapy. In randomized clinical studies involving patients with HBeAg-positive CHB, treatment with pegylated interferon (PegIFN)-alpha is associated with higher and more durable HBeAg seroconversion rates than are lamivudine and adefovir. More recently, newer generation oral nucleos(t)ide analogs (NAs) have become available. These include entecavir, telbivudine and tenofovir, and they demonstrate superior antiviral potency and efficacy. This review examines the importance of HBeAg seroconversion as an end point for therapy in the treatment of patients with HBeAg-positive CHB, and examines the rates and durability of HBeAg seroconversion with PegIFN and oral NA therapy. The mechanisms for enhanced HBeAg seroconversion rates with new-generation NAs are also discussed.

Clearance of serum HBsAg and anti-HBs seroconversion following antiviral therapy for chronic hepatitis B

In this study, we have analyzed the evolution of serum HBsAg levels in 16 patients with chronic hepatitis B who showed an HBsAg seroconversion following antiviral therapy. The data showed that the clearance of serum HBsAg is slower than that of serum HBV DNA, which may reflect a slow kinetics of clearance of infected hepatocytes. Interestingly, HBsAg was detectable for a longer time using the Architect assay than with the Bio-Rad assay. As viremia suppression is achieved in most patients under therapy with the new generation of nucleoside analogs, these data suggest that the quantitative monitoring of serum HBsAg may represent a novel tool for the assessment of antiviral therapy efficacy.

Identification of a hepatitis B virus S gene mutant in lamivudine-treated patients experiencing HBsAg seroclearance

BACKGROUND & AIMS

Seroclearance of hepatitis B virus (HBV) surface antigen (HBsAg) is a rare event in chronic hepatitis B patients receiving lamivudine therapy. It is generally believed to be a benevolent sign, implicating clearance of viremia. The aim of this study is to examine the authenticity of this dogma.

METHODS

In a 5-year period, 11 patients treated with lamivudine experienced seroclearance of HBsAg. The clinical data were examined. The HBV S gene sequences derived from the patient's serum samples before and after seroclearance of HBsAg were analyzed.

RESULTS

Serum HBV-DNA could be detected by nested polymerase chain reaction (PCR) in all 11 patients, by 1-step PCR in 8, and by Cobas Amplicor HBV-DNA test (>200 copies/mL) in 5. A mutation hot spot, P120A in the S gene, was identified in 6 of the 11 patients. Site-directed mutagenesis experiments indicated that the Ausria-II RIA test failed to detect this mutant. Decreased sensitivity of detection was also observed when other monoclonal antibodies were applied.

CONCLUSIONS

Seroclearance of HBsAg during lamivudine therapy may not indicate viral clearance. Specifically, it may be caused by a point mutation in the S gene, which results in detection failure. In such patients, further verification and follow-up using a sensitive HBV-DNA test are advised.

Recommendations and potential future options in the treatment of hepatitis B

The natural history of chronic hepatitis B should be clearly defined before appropriate recommendations for treatment can be advocated. In patients who acquire the disease in early life, the complications of chronic hepatitis B continue to occur as a result of prolonged insidious damage to the liver, even in the low viraemic phase. Treatment that ends with hepatitis B e antigen seroconversion with hepatitis B virus DNA levels just below 10(5) copies/ml may not be sufficient. Patients with mild elevation of alanine aminotransferase levels are already at considerable risk of developing complications. Treatment strategy should aim at maximal and prolonged viral suppression to the lowest possible hepatitis B virus DNA levels. Nucleotide/nucleoside analogues will become the mainstay of treatment. Future treatment strategic plans should target maximising antiviral potency and minimising the chance of drug resistance.

Diagnosis and management of clinical and subclinical cobalamin deficiency: advances and controversies

Major recent developments in cobalamin deficiency include issues such as the nature of food-cobalamin malabsorption, sensitivities and specificities of diagnostic tests, and emerging data on oral therapy. These have been heavily influenced by studies of subclinical deficiency, which has a much slower progression (which may be nonlinear), arises from different causes, and poses different, more public health-oriented management considerations than the less frequent but much more medically important entity of clinically expressed deficiency. Distinguishing carefully between the two deficiency states is helpful because clinical lessons and strategies derived from one may not apply equally to the other, as illustrated by controversial decisions about clinical issues such as the serum cobalamin level diagnostic of deficiency. Reassessment of diagnostic and management approaches, including improving our ability to diagnose cobalamin malabsorption, is required.

Fatal liver failure with the emergence of hepatitis B surface antigen variants with multiple stop mutations after discontinuation of lamivudine therapy

Treatment of chronic hepatitis B virus (HBV) infection with lamivudine is effective and well-tolerated. However, discontinuation of the treatment is associated frequently with acute exacerbation of liver diseases. A patient suffering from acute liver failure after discontinuation of lamivudine treatment is described. The patient was treated with lamivudine for 4 months and ceased the treatment without consulting. After receiving lamivudine, the patient developed anti-HBs and became negative for hepatitis B surface antigens (HBsAg). However, HBV DNA reappeared to a level of 6.47 x 10(5) copies/ml. The patient died due to acute liver failure. Sequencing of HBV isolates revealed that mutations including G145R and stop codons occurred within the HBsAg coding region. In conclusion, HBV replication resumed after the uncontrolled cessation of lamivudine treatment in this patient and may have triggered the process leading to liver failure. Anti-HBs antibody appeared and may be the selective force for the emergence of HBV mutants.

Therapy of hepatitis B -- viral suppression or eradication?

The practicing clinician is currently faced with a number of treatment options for chronic hepatitis B. Beginning in 1998 with the licensing of lamivudine and subsequently adefovir, the treatment paradigm shifted from 4 to 6 months of conventional alfa interferon to a year of nucleoside analog therapy. However, prolonged treatment with nucleoside analogs is often needed to optimize virological response. Recently, a 48-week regimen of pegylated interferon for hepatitis B e antigen (HBeAg)-positive and HBeAg-negative chronic hepatitis B has been shown to be effective, and long-term nucleoside analog therapy has been demonstrated to maintain viral suppression. These findings have added to the complexity of decision-making and have raised questions about whether a finite course of pegylated interferon or nucleoside analog therapy, with possible long-term maintenance, is better as first-line therapy. Each of these fundamentally different approaches has advantages and limitations, and both have a place in the therapeutic armamentarium against chronic hepatitis B. Long-term therapy with nucleoside analogs, however, raises a number of practical concerns that have not been fully addressed as of yet. I will present evidence in support of the recommendation that antiviral therapy should ideally be directed toward achieving the highest rate of viral clearance with the shortest interval of treatment.

One-year entecavir or lamivudine therapy results in reduction of hepatitis B virus intrahepatic covalently closed circular DNA levels

Entecavir and lamivudine are potent nucleoside analogues that can suppress hepatitis B virus (HBV) replication. However, the effects of these two antiviral agents on intrahepatic total HBV DNA and covalently closed circular DNA (cccDNA) are not known. In this study, we aimed to assess the effect of 48 weeks of entecavir/lamivudine therapy on intrahepatic total HBV DNA and cccDNA levels. Forty chronic hepatitis B patients, participating in two Phase III entecavir trials at our centre, were randomized to receive 48 weeks of either 0.5 mg once daily of entecavir (n = 21) or 100 mg once daily of lamivudine (n = 19). Their serological, virological and biochemical responses, as well as intrahepatic HBV DNA levels were monitored. There was no significant difference between entecavir and lamivudine therapy in terms of post-treatment serological, virological and biochemical responses. Both nucleoside analogues reduced serum viral load, intrahepatic total HBV DNA, and cccDNA by about 4.8 logs, 2 logs, and 1 log respectively. An increase in the proportion of intrahepatic HBV DNA in the form of cccDNA was seen after 48 weeks of therapy. In conclusion, both entecavir and lamivudine can successfully reduce intrahepatic HBV DNA and cccDNA. CccDNA becomes the dominant form of HBV DNA during viral suppression and is possibly responsible for viral rebound after short-term antiviral therapy.