Discontinuation of oral antivirals in chronic hepatitis B: A systematic review

EASL 2017 Clinical Practice Guidelines on the management of hepatitis B virus infection

Hepatitis B virus (HBV) infection remains a global public health problem with changing epidemiology due to several factors including vaccination policies and migration. This Clinical Practice Guideline presents updated recommendations for the optimal management of HBV infection. Chronic HBV infection can be classified into five phases: (I) HBeAg-positive chronic infection, (II) HBeAg-positive chronic hepatitis, (III) HBeAg-negative chronic infection, (IV) HBeAg-negative chronic hepatitis and (V) HBsAg-negative phase. All patients with chronic HBV infection are at increased risk of progression to cirrhosis and hepatocellular carcinoma (HCC), depending on host and viral factors. The main goal of therapy is to improve survival and quality of life by preventing disease progression, and consequently HCC development. The induction of long-term suppression of HBV replication represents the main endpoint of current treatment strategies, while HBsAg loss is an optimal endpoint. The typical indication for treatment requires HBV DNA >2,000IU/ml, elevated ALT and/or at least moderate histological lesions, while all cirrhotic patients with detectable HBV DNA should be treated. Additional indications include the prevention of mother to child transmission in pregnant women with high viremia and prevention of HBV reactivation in patients requiring immunosuppression or chemotherapy. The long-term administration of a potent nucleos(t)ide analogue with high barrier to resistance, i.e., entecavir, tenofovir disoproxil or tenofovir alafenamide, represents the treatment of choice. Pegylated interferon-alfa treatment can also be considered in mild to moderate chronic hepatitis B patients. Combination therapies are not generally recommended. All patients should be monitored for risk of disease progression and HCC. Treated patients should be monitored for therapy response and adherence. HCC remains the major concern for treated chronic hepatitis B patients. Several subgroups of patients with HBV infection require specific focus. Future treatment strategies to achieve 'cure' of disease and new biomarkers are discussed.

What is new on HBsAg and other diagnostic markers in HBV infection?

Challenges in the management of chronic hepatitis B virus (HBV) infection involve the prediction of the natural course to identify patients who require antiviral therapy and the prediction of functional cure as ultimate goal of antiviral therapy. HBV DNA as marker for viral replication is important but not sufficient for an adequate management of patients with chronic HBV infection. Data on the quantification of additional HBV marker such as hepatitis B surface antigen (HBsAg), hepatitis B core-related antigen (HBcrAg) and hepatitis B virus RNA (HBV RNA) have accumulated in recent years. Here we review the current evidence how to use these markers and discuss open issues that require additional research.

Incidence and predictors of HBV relapse after cessation of nucleoside analogues in HBeAg-negative patients with HBsAg ≤ 200 IU/mL

The predictors of hepatitis B virus (HBV) relapse and HBsAg loss after cessation of nucleos(t)ide analogues (NA) in HBeAg-negative patients with end-of-treatment HBsAg ≤ 200 IU/mL remains unclear. The study recruited 119 chronic hepatitis B (CHB) patients who achieved end-of-treatment HBsAg ≤ 200 IU/mL, were treated with lamivudine (n = 34) and entecavir (n = 85). The 5-year rates of post-treatment virological relapse, clinical relapse, and HBsAg loss at 60 months were 39.4%, 27.6%, and 45.9%, respectively. Cox regression analysis revealed that HBV DNA at entry and end-of-treatment HBsAg levels were independent predictors of virolgical and clinical relapse. HBV genotype C and end-of-treatment HBsAg were independent factors of HBsAg loss. Patients with a combination of end-of-treatment HBsAg < 50 IU/mL and HBV DNA < 2 × 10⁵ IU/mL at entry experienced the lowest virological and clinical relapse rates (5% and 0% at 60 months, respectively). In contract, patients with a combination of end-of-treatment HBsAg ≥ 50 IU/mL and HBV DNA ≥ 2 × 10⁵ IU/mL at entry experienced high virological and clinical relapse (80.7% and 71.5% at 60 months, respectively). No patients experienced hepatic decompensation when clinical relapse occurred after timely retreatment. A combination of HBV DNA levels at entry and end-of-treatment HBsAg levels was useful for predicting the post-treatment HBV relapse in HBeAg-negative patients with HBsAg ≤ 200 IU/mL.

Chronic hepatitis B: Immunological profile and current therapeutic vaccines in clinical trials

More than 250million people worldwide are chronically infected with hepatitis B virus (CHB), and over half a million die each year due to CHB-associated liver complications such as cirrhosis and hepatocellular carcinoma. The translation of immunological knowledge about CHB into therapeutic strategies aiming to a sustainable hepatitis B virus (HBV) clearance has been challenging. In recent years, however, the understanding on the immune effectors required to overcome chronicity has notably increased thanks to preclinical and clinical research. Therapeutic vaccination may prove to be useful for treating CHB patients when coupled with current antiviral agents and other immunomodulatory strategies. This review summarizes current data and future perspectives on therapeutic vaccination. Other treatment alternatives that could be combined with vaccines for a complete cure from hepatitis B virus infection are also discussed.

Discontinuation of lamivudine treatment in HBeAg-negative chronic hepatitis B: a pilot study with long-term follow-up

BACKGROUND

Finite treatment of hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (CHB) with nucleoside/nucleotide analogues (NAs) is important in resource-limited countries. Outcome of treatment discontinuation in patients on long-term lamivudine (LVD) was assessed in a single centre observational pilot study in the current study.

METHODS

Non-cirrhotic patients on LVD for at least 5 years with undetectable HBV DNA on at least two consecutive assessments were offered to stop treatment. Biochemical, serological and virological measures were determined at 3-6 month intervals after treatment discontinuation. Serum quantitative hepatitis B surface antigen (HBsAg) was determined at treatment discontinuation and 5-6 years thereafter. NA treatment was re-instituted in patients with confirmed viral rebound defined as HBV DNA >20,000 IU/ml. Relapser patients were no longer followed but were re-assessed 6 years after treatment cessation.

RESULTS

LVD was discontinued in 23 patients. 8 patients relapsed within 1 year and NA treatment was restarted; 15 patients (65%) were non-relapsers. Thirteen of them were followed for at least 5 years. Two patients had undetectable HBV DNA throughout the follow-up period. In the rest, HBV DNA fluctuated at low levels. Two patients cleared HBsAg 24 and 36 months after stopping treatment. Quantitative HBsAg levels 5-7 years after treatment discontinuation were lower in non-relapser compared to relapser patients (1.21 IU/ml ±0.98 versus 2.71 ±0.76; P=0.002). Of 8 relapser patients 1 patient had HBsAg levels less than 100 IU/ml compared to 11 out of 13 non-relapser patients (P=0.0022).

CONCLUSIONS

These data suggest that cessation of NA treatment is a viable option after a reasonable treatment duration in patients with HBeAg-negative CHB and that HBsAg clearance may become an achievable target in these patients.

Hepatitis B virus long-term impact of antiviral therapy nucleot(s)ide analogues (NUCs)

The goal of antiviral therapy is to improve the quality of life and survival of patients with chronic hepatitis B (CHB) by halting the progression to cirrhosis, end-stage liver disease or hepatocellular carcinoma (HCC), thus preventing anticipated liver-related death. Oral administration of potent and less resistance-prone nucleot(s)ide analogues (NUCs), such as entecavir (ETV) and tenofovir disoproxil fumarate (TDF) has become the most popular treatment strategy worldwide because of their excellent efficacy and safety profile as well as easy management confirmed in both registration trials and in clinical practice studies. Long-term administration of ETV or TDF suppresses HBV replication in >95% of patients, resulting in biochemical remission, histological improvement including the regression of cirrhosis and prevention or reversal of clinical decompensation but not the development of HCC, particularly in patients with cirrhosis. Moreover, NUCs can be administered to all patients including those with severe liver disease, the elderly and in those who do not respond, are unwilling to take or have contraindications to interferon. The need for long-term, perhaps indefinite, treatment is the main limitation of NUCs therapy with the associated costs, unknown long-term safety and the low rates of hepatitis B surface antigen (HBsAg) seroclearance, which is still the best stopping rule for NUCs-treated patients with cirrhosis.

When can we stop nucleoside analogues in patients with chronic hepatitis B?

Treatment with nucleoside analogue (NAs) is now the most common treatment for chronic hepatitis B (CHB) and is recommended by all guidelines. Stopping NAs is a controversial issue in these patients, unless the clinical endpoints of HBeAg seroconversion or HBsAg seroclearance are achieved. While HBeAg seroconversion can occur in a significant number of patients, HBsAg seroclearance rates are low. HBsAg seroclearance is increasingly accepted as the ideal end of treatment, representing a functional cure. Treatment withdrawal leads to relapse in 50% of patients who achieve HBeAg seroconversion and complete at least 12 months of consolidation therapy. In HBeAg negative CHB, the Asian Pacific Association for the Study of the Liver (APASL) stopping rules show that although clinical relapse occurs in approximately 43% and virological relapse occurs in 70%, very few patients experience flare or decompensation. NAs treatment for >2 years was associated with a lower rate of relapse. Recently, stopping NA therapy was shown to be associated with HBsAg in 20%-39% of HBeAg negative patients and more frequently in those with low quantitative HBsAg (qHBsAg). However, the most optimal level is unclear. Quantitative HBsAg is becoming a useful tool to predict a sustained response or relapse before stopping therapy. In conclusion, stopping NA therapy is generally safe and can be an option in specific situations such as HBeAg seroconversion. However, it is associated with disease relapse. Thus, patient selection based on qHBsAg may help identify patients who are more likely to achieve HBsAg seroclearance or a sustained response.

Treatment of chronic hepatitis B infection-2017

Since the registration of the first effective nucleoside analogue against the hepatitis B virus almost two decades ago, major progress has been made in the management of chronic hepatitis B infection. However, hepatitis B-related morbidity and mortality remain a major global health threat. This is partly due to the escalating costs and the decrease in compliance related to the need for prolonged therapy for most patients who cannot be "cured". New biomarkers such as quantitative hepatitis B surface antigen might help to determine if hepatitis B e antigen negative patients can be taken off nucleos(t)ide analogues. On the other hand, novel compounds that target the viral life cycle or modulate host immune response are in the pipeline. In the next few years, one should expect breakthrough advancement to be made leading to a "cure" for patients with chronic hepatitis B infection by inducing hepatitis surface antigen loss with or without the development of the hepatitis B surface antibody. In addition, attention and necessary actions should also be taken in patients with hepatitis B infection who are being treated with immunosuppressive therapy and direct anti-viral (DAAs) agents for hepatitis C infection to prevent hepatitis from hepatitis B reactivation.

Clinical Relapse After Cessation of Tenofovir Therapy in Hepatitis B e Antigen-Negative Patients

BACKGROUND & AIMS

Of the hepatitis B e antigen-negative chronic hepatitis B patients with more than 1 year of sustained hepatitis B virus (HBV) suppression during therapy, the 1-year clinical relapse rate after cessation of entecavir therapy was 45%, of which 25.6% occurred within 6 months. The events after cessation of another preferred drug tenofovir were investigated.

METHODS

A retrospective-prospective study was conducted in 85 hepatitis B e antigen-negative chronic hepatitis B patients with sustained HBV suppression who had stopped tenofovir therapy and were monitored every 1 to 3 months for a median duration of 39 weeks (range, 4-133 wk).

RESULTS

Clinical relapse occurred in 38 patients, 57.9% and 86.8% within 3 and 6 months, respectively, with an estimated 1-year cumulative incidence of 52%. The optimal duration of therapy and consolidation therapy were calculated to be 3 and 2 years, respectively. Of the relapsers, 81.6% and 57.9% showed an alanine aminotransferase level greater than 5 and 10 times the upper limit of normal, respectively, 23.7% showed a bilirubin level of 2 mg/dL or greater, and 2 developed hepatic decompensation. Relapsers had significantly higher pretherapy baseline hepatitis B surface antigen level, more prior anti-HBV therapy experience, later alanine aminotransferase level normalization, and a shorter duration of treatment and consolidation therapy. Cox regression analyses showed that treatment for more than 3 years combined with consolidation therapy for more than 2 years was an independent significant manageable factor of clinical relapse (adjusted hazard ratio, 0.387; P = .008). With this combination, the clinical relapse rate was reduced to 30%.

CONCLUSIONS

Clinical relapses occurred mostly within 6 months, with high alanine aminotransferase and serum bilirubin levels. Closer monitoring, monthly in the first 3 to 6 months, with timely re-treatment is mandatory for a safe cessation of tenofovir therapy.

The HBV Drugs Work: Now What?

Chemotherapeutic agents for Hepatitis B virus (HBV) suppression work, but only when administered to the patient. They do not appear to promote durable, long-term immunological control. After 3 years of effective anti-HBV therapy, a small percentage of patients maintained good control, manifest by controlled serum liver enzymes, low-level HBV-DNA, and controlled HBsAg concentrations. However, this did not occur in the majority of patients. We need a better understanding of the defects in HBV immunity and how to induce effective reconstitution that will maintain viral suppression, albeit either through innate or adaptive immunity.

Treatment for hepatitis B in patients with drug resistance

Persistent hepatitis B virus (HBV) infections affect about 240 million patients worldwide that are at risk of developing liver cirrhosis or hepatocellular carcinoma. HBV is a small, partially double stranded DNA virus with four overlapping genes and a unique life cycle, which involves the generation of an RNA template for replication via reverse transcription. Mutations occur frequently during chronic infection, and particular selection pressures select distinct mutants. Nucleoside and nucleotide analogues like lamivudine (LMV), entecavir (ETV), telbivudine (LdT), adefovir dipivoxil (ADV) and tenofovir (TDF) are used to achieve long-term suppression of viral replication. Importantly, these drugs have different barriers to resistance, explaining the higher incidence of treatment failure in the past due to drug resistant viral strains for the older compounds LMV, LdT and ADV. On a molecular level, drug resistant mutations usually affect the reverse transcriptase domain of the HBV polymerase protein. Secondary compensatory mutations restore the replication fitness of the mutant virus. From a clinical point of view, patients undergoing antiviral therapy require regular testing for HBV DNA (every 3-6 months). In case of insufficient viral suppression or viral breakthrough (>1 log increase in HBV DNA above nadir), strict adherence to therapy needs to be ensured. If drug resistance is suspected or even molecularly confirmed, rescue therapy strategies exist, usually switching to a noncross-resistant antiviral drug. LMV, LdT and ETV resistant HBV can be treated with TDF monotherapy, ADV resistance with ETV or TDF, and insufficient responses to TDF may require ETV either as mono- or combination therapy. Complex treatment histories with many antivirals may sometimes necessitate the combination of highly effective antivirals like ETV and TDF. Novel treatment targets such as core (capsid) inhibitors, siRNA targeting protein translation, entry inhibitors or immune modulators aim at improving the efficacy of antivirals in order to (functionally) cure hepatitis B.

Review of Laboratory Tests used in Monitoring Hepatitis B Response to Pegylated Interferon and Nucleos(t)ide Analog Therapy

There are only two currently approved classes of hepatitis B virus (HBV) antiviral agents, pegylated interferon (Peg-IFN), and nucleos(t)ide analogs (NAs) for chronic HBV infection. Although Peg-IFN is used for a finite 48-week duration and offers a greater chance of sustained off-treatment virological response, it is poorly tolerated and can only be offered to selected patients. The NAs are well tolerated but require prolonged therapy due to risk of relapse with treatment cessation. There is evolving data that novel virological assays (e.g., quantitative hepatitis B surface antigen, quantitative hepatitis B core antigen, quantitative antibody to core protein) in combination with hepatitis B genotype and more sensitive HBV DNA polymerase chain reaction (PCR) assays may be useful to predict response to IFN as well as off-treatment NA durability. Utilization of these clinical laboratory tests may be important given the development of novel anti-HBV therapies, hoping to achieve a cure for chronic hepatitis B infection.