Association Between Level of Hepatitis D Virus RNA at Week 24 of Pegylated Interferon Therapy and Outcome

Quantification of serum HDV RNA by Robogene 2.0 in HDV patients is significantly influenced by the extraction methods

BACKGROUND AND AIM

Management of chronic hepatitis delta (CHD) requires reliable tests for HDV RNA quantification. The aim of the study was to compare two extraction methods for the quantification of HDV RNA in untreated and bulevirtide (BLV)-treated CHD patients.

METHODS

Frozen sera from untreated and BLV-treated CHD patients were tested in a single-centre study for HDV RNA levels (Robogene 2.0, Roboscreen GmbH, Leipzig, Germany; LOD 6 IU/mL) with two extraction methods: manual (INSTANT Virus RNA/DNA kit; Roboscreen GmbH, Leipzig, Germany) versus automated (EZ1 DSP Virus Kit; Qiagen, Hilden, Germany). BLV-treated patients were sampled at baseline and during therapy.

RESULTS

Two hundred sixty-four sera collected from 157 CHD (139 untreated, 18 BLV-treated) patients were analysed: age 51 (28-78), 59% males, 90% of European origin, 60% cirrhotics, ALT 85 (17-889) U/L, HBsAg 3.8 (1.7-4.6) Log IU/mL, 81% HBV DNA undetectable, 98% HDV genotype 1. Median HDV RNA was 4.53 (.70-8.10) versus 3.77 (.70-6.93) Log IU/mL by manual versus automated extraction (p < .0001). Manual extraction reported similar HDV RNA levels in 31 (20%) patients, higher in 119 (76%) [+.5 and +1 log10 in 60; > +1 log10 in 59] and lower in 7 (4%). Among 18 BLV-treated patients, rates of HDV RNA < LOD significantly differed between the two assays at Weeks 16 and 24 (0% vs. 22%, p = .02; 11% vs. 44%, p = .03), but not at later timepoints. By contrast, virological response rates were similar.

CONCLUSIONS

Quantification of HDV RNA by Robogene 2.0 is influenced by the extraction method, the manual extraction being 1 Log more sensitive.

Interferon-based treatment of chronic hepatitis D

Treatment of hepatitis D virus (HDV) infection has been based on the administration of interferon-alfa for more than three decades. First studies to treat HDV-infected patients with type 1 interferons were already performed in the 1980s. Several smaller trials and case series were reported thereafter. During the mid 2000s the use of pegylated interferons for hepatitis D was established. Since then, additional trials were performed in different countries exploring strategies to personalize treatment including extended treatment durations. The overall findings were that about one-quarter to one-third of patients benefit from interferon treatment with persistent suppression of HDV replication. However, only few patients achieve also functional cure of hepatitis B with HBsAg loss. Importantly, several studies indicate that successful interferon treatment is associated with improved clinical long-term outcomes. Still, only a proportion of patients with hepatitis D can be treated with interferons. Even though alternative treatments are currently developed, it is likely that pegylated interferon-alfa will still have an important role in the management of hepatitis D - either alone or in combination. Therefore, better biomarkers are needed to select patients with a high likelihood to benefit from interferon-based treatments. In this review we are discussing basic principles of mode of action of interferon alpha against HDV, summarize previous data on interferon treatment of hepatitis D and give an outlook on potential combinations with novel drugs currently in development.

Treatment endpoints for chronic hepatitis D

Management of chronic hepatitis D (CHD) has entered a new era. In this new era, the virus entry inhibitor bulevirtide has received conditional approval as a treatment for compensated CHD. Three phase 3 studies with two new compounds are ongoing for the treatment of CHD. In this context, surrogate markers of treatment efficacy have been well defined for chronic hepatitis B (CHB) (7) and chronic hepatitis C (8) but not for CHD. The aim of this review is to give a perspective on treatment endpoints in CHD. For this, we took guidance from CHB studies and tried to make suggestions which differed according to finite versus prolonged treatment durations and also took into account the different characteristics of the new compounds.

EASL Clinical Practice Guidelines on hepatitis delta virus

Hepatitis D virus (HDV) is a defective virus that requires the hepatitis B virus to complete its life cycle and cause liver damage in humans. HDV is responsible for rare acute and chronic liver diseases and is considered the most aggressive hepatitis virus. Acute infection can cause acute liver failure, while persistent infection typically causes a severe form of chronic hepatitis which is associated with rapid and frequent progression to cirrhosis and its end-stage complications, hepatic decompensation and hepatocellular carcinoma. Major diagnostic and therapeutic innovations prompted the EASL Governing Board to commission specific Clinical Practice Guidelines on the identification, virologic and clinical characterisation, prognostic assessment, and appropriate clinical and therapeutic management of HDV-infected individuals.

Emerging drugs for hepatitis D

INTRODUCTION

Chronic hepatitis delta (CHD) is the most severe form of chronic viral hepatitis. Until recently, its treatment consisted of pegylated interferon alfa (pegIFN) use.

AREAS COVERED

Current and new drugs for treating CHD. Virus entry inhibitor bulevirtide has received conditional approval by the European Medicines Agency. Prenylation inhibitor lonafarnib and pegIFN lambda are in phase 3 and nucleic acid polymers in phase 2 of drug development.

EXPERT OPINION

Bulevirtide appears to be safe. Its antiviral efficacy increases with treatment duration. Combining bulevirtide with pegIFN has the highest antiviral efficacy short-term. The prenylation inhibitor lonafarnib prevents hepatitis D virus assembly. It is associated with dose dependent gastrointestinal toxicity and is better used with ritonavir which increases liver lonafarnib concentrations. Lonafarnib also possesses immune modulatory properties which explains some post-treatment beneficial flare cases. Combining lonafarnib/ritonavir with pegIFN has superior antiviral efficacy. Nucleic acid polymers are amphipathic oligonucleotides whose effect appears to be a consequence of phosphorothioate modification of internucleotide linkages. These compounds led to HBsAg clearance in a sizeable proportion of patients. PegIFN lambda is associated with less IFN typical side effects. In a phase 2 study it led to 6 months off treatment viral response in one third of patients.

Hepatitis D virus: Improving virological knowledge to develop new treatments

Hepatitis delta virus (HDV), a satellite of hepatitis B virus (HBV), possesses the smallest viral genome known to infect animals. HDV needs HBV surface protein for secretion and entry into target liver cells. However, HBV is dispensable for HDV genome amplification, as it relies almost exclusively on cellular host factors for replication. HBV/HDV co-infections affect over 12 million people worldwide and constitute the most severe form of viral hepatitis. Co-infected individuals are at higher risk of developing liver cirrhosis and hepatocellular carcinoma compared to HBV mono-infected patients. Bulevirtide, an entry inhibitor, was conditionally approved in July 2020 in the European Union for adult patients with chronic hepatitis delta (CHD) and compensated liver disease. There are several drugs in development, including lonafarnib and interferon lambda, with different modes of action. In this review, we detail our current fundamental knowledge of HDV lifecycle and review antiviral treatments under development against this virus, outlining their respective mechanisms-of-action. Finally, we describe the antiviral effect these compounds are showing in ongoing clinical trials, discussing their promise and potential pitfalls for managing HDV infected patients.

Non-invasive diagnosis and follow-up of chronic infection with hepatitis B virus

Diagnosis of chronic hepatitis B virus (HBV) infection, initial staging of infection and monitoring of treated and untreated patients are mainly based on clinical, biological and imaging criteria allowing a complete non-invasive management for the majority of patients. Along to the conventional virological tools, rapid diagnostic tests and blotting paper tests for HBV DNA are validated alternatives. After diagnosis, the initial work-up should include HIV, HCV and HDV serologies, HBeAg status, and HBsAg and HBV DNA quantification. Assessment of severity (inflammation and fibrosis) is based on ALT serum levels and non-invasive evaluation of liver fibrosis by elastography or blood tests, which must be interpreted cautiously using specific cut-offs and taking into account ALT levels. Taken together, these parameters allow disease classification and treatment decision. Decision of hepatocellular carcinoma screening by ultra-sound every six months may be difficult in non-cirrhotic patients and the use of risk-scores such as PAGE-B is encouraged. Chronic HBV infection often has a dynamic and often unpredictable profile and regular monitoring is mandatory. In untreated patients, regular (3-12 months) follow-up should include ALT and HBV DNA serum levels. Periodical HBsAg quantification and non-invasive evaluation of liver fibrosis may refine disease outcome and prognosis. In treated patients, checking efficacy is mainly based on HBV DNA negativity. In patients with advanced fibrosis, evolution of liver stiffness can be useful for portal hypertension evaluation, but its improvement should not be considered to stop hepatocellular carcinoma screening. Finally, new parameters (HBV RNA, HBcrAg) are promising but their use is still restricted for research.

Clinical trials in hepatitis D virus: Measuring success

Chronic hepatitis D infection results in the most severe form of chronic viral hepatitis but currently lacks effective treatment options. Therapy with pegylated interferon alpha is recommended for finite treatment duration by major liver societies. Still, it is plagued by low rates of sustained virologic response (SVR) and frequent relapses even if SVR is achieved. Recently, a wave of investigational therapies has come under evaluation, including bulevirtide, lonafarnib, pegylated interferon lambda, and REP-2139 creating excitement with this viral infection. However, there has been significant variability in the endpoints used to evaluate these therapeutics. One of the recently introduced endpoints is characterized by a decline in HDV RNA by 2 logs, with or without achieving an undetectable serum hepatitis D virus (HDV) RNA, as a marker of virologic response. Furthermore, this measure has been combined with alanine aminotransferase normalization, also known as a biochemical response, to formulate the primary endpoint of several late-stage studies. Per recent guidance by the US Food and Drug Administration, these should be surrogate endpoints that will ultimately portend long-term clinical benefits. These clinical benefits may include reducing the risk of progression to cirrhosis, hepatic decompensation, hepatocellular carcinoma, liver transplantation, and mortality. However, the optimal way to measure success in HDV clinical trials remains unknown and will continue to evolve.

Future anti-HDV treatment strategies, including those aimed at HBV functional cure

HDV is a defective virus that uses the HBV surface antigen to enter hepatocytes. It is associated with an accelerated course of liver fibrosis progression and an increased risk of hepatocellular carcinoma. Negative HDV RNA 24 weeks after the end of therapy has been proposed as an endpoint but late relapses make this endpoint suboptimal, hence HBsAg loss appears to be more appropriate. Current HBV antiviral agents have poor activity against HDV hence the search for improved therapy. Drugs only active against HDV, such as lonafarnib, have shown efficacy in combination with nucleoside analogues and peginterferon, but do not lead to HBsAg loss. HBsAg loss sustained 24 weeks after the end of therapy with negative HBV DNA is termed functional cure. Agents that are being investigated for functional cure include those that inhibit replication such as entry inhibitors, polymerase inhibitors and capsid assembly modulators but seldom lead to functional cure. Agents that reduce HBV antigen load such as RNA interference and inhibitors of HBsAg secretion are promising. Immunomodulators on their own seldom achieve functional cure, hence these agents in combination to assess the optimal combination are being investigated. Consequently, agents leading to functional cure of HBV are ideal for both HBV and HDV.

Response-guided long-term treatment of chronic hepatitis D patients with bulevirtide-results of a "real world" study

BACKGROUND AND AIM

Bulevirtide (BLV) blocks the uptake of the hepatitis D virus (HDV) into hepatocytes via the sodium/bile acid cotransporter NTCP. BLV was conditionally approved by the EMA but real-life data on BLV efficacy are limited.

METHODS

Patients were treated with BLV monotherapy. Patients who did not achieve further decreases in HDV-RNA after 24 weeks were offered PEG-IFN as an add-on therapy in a response-guided manner.

RESULTS

Twenty-three patients (m: 10, f: 13; mean age: 47.9 years, cirrhosis: 16; median ALT: 71 IU/ml; median HDV-RNA: 2.1 × 10⁵ copies/ml) started BLV monotherapy (2 mg/day: 22; 10 mg/day: 1). Twenty-two completed ≥24 weeks of treatment (24-137 weeks): Ten (45%) were classified as BLV responders at week 24. BLV was stopped in two patients with >6 months HDV-RNA undetectability, but both became HDV-RNA positive again. One patient was transplanted at week 25. One patient terminated treatment because of side effects at week 60. Ten patients are still on BLV monotherapy. Adding PEG-IFN in eight patients induced an HDV-RNA decrease in all (1.29 ± 0.19 [SD] log within 12 weeks). HDV-RNA decreased by >2log or became undetectable in 45%(10/22), 55%(11/20), 65% (13/20) and 69% (9/13); and ALT levels normalised in 64% (14/22), 85% (17/20), 90% (18/20) and in 92% (12/13) patients at weeks 24, 36, 48 and 60, respectively. Portal pressure decreased in 40% (2/5) of patients undergoing repeated measurement under BLV therapy.

CONCLUSION

Long-term BLV monotherapy is safe and effectively decreases HDV-RNA and ALT-even in patients with cirrhosis. The optimal duration of BLV treatment alone or in combination with PEG-IFN remains to be established. An algorithm for a response-guided BLV treatment approach is proposed.

Chronic hepatitis D-What is changing?

Hepatitis D virus (HDV) infection is a chronic viral disease of the liver that is still largely considered to be incurable due to lack of effective treatment options. Without treatment, the risk for the development of advanced liver disease, cirrhosis and hepatocellular carcinoma is significantly high. Currently, new therapeutic options are emerging out of ongoing phase 3 clinical trials, promising a new hope of cure for this devastating liver infection. Recently, bulevirtide, a first in its class HDV entry inhibitor, has received conditional authorization of use from the European Medicines Agency (EMA) and was also submitted for approval in the United States. Other novel therapeutic options in clincal trials include interferon lambda, the prenylation inhibitor lonafarnib and nucleic acidic polymers (NAPs). This review describes all recent advances and ongoing changes to the field of HDV therpaeutics.

Hepatitis delta virus: From infection to new therapeutic strategies

The hepatitis delta virus (HDV) is a small RNA virus that encodes a single protein and which requires the hepatitis B virus (HBV)-encoded hepatitis B surface antigen (HBsAg) for its assembly and transmission. HBV/HDV co-infections exist worldwide and show a higher prevalence among selected groups of HBV-infected populations, specifically intravenous drug users, practitioners of high-risk sexual behaviours, and patients with cirrhosis and hepatocellular carcinoma. The chronic form of HDV-related hepatitis is usually severe and rapidly progressive. Patterns of the viral infection itself, including the status of co-infection or super-infection, virus genotypes (both for HBV and HDV), and persistence of the virus’ replication, influence the outcome of the accompanying and manifested liver disease. Unfortunately, disease severity is burdened by the lack of an effective cure for either virus type. For decades, the main treatment option has been interferon, administered as mono-therapy or in combination with nucleos(t)ide analogues. While its efficacy has been reported for different doses, durations and courses, only a minority of patients achieve a sustained response, which is the foundation of eventual improvement in related liver fibrosis. The need for an efficient therapeutic alternative remains. Research efforts towards this end have led to new treatment options that target specific steps in the HDV life cycle; the most promising among these are myrcludex B, which inhibits virus entry into hepatocytes, lonafarnib, which inhibits farnesylation of the viral-encoded L-HDAg large hepatitis D antigen, and REP-2139, which interferes with HBsAg release and assembly.

Experimental Drugs for the Treatment of Hepatitis D

Chronic hepatitis D virus infection is the most severe form of viral hepatitis. Antiviral treatment is urgently needed to prevent patients from developing end stage liver disease or hepatocellular carcinoma. Treatment options were limited to off-label use of pegylated interferon alfa until conditional approval of bulevirtide by the EMA (European Medicines Agency) in July 2020. However, several other antiviral compounds are currently investigated and represent promising agents for the treatment of chronic HDV infection.

HBV/HDV Co-Infection: Epidemiological and Clinical Changes, Recent Knowledge and Future Challenges

Several investigations have been published on Hepatitis Delta Virus (HDV) infection in recent years, from which we have drawn the salient data to provide readers with useful information to improve their knowledge on the subject. HDV genotypes 5–8 have been recently imported to Western countries from central Africa, whose clinical relevance deserves further investigation. Ongoing HDV replication has been identified as an independent predictor of progression to cirrhosis and HCC for patients with HDV chronic hepatitis (HDV-CH). Long-term treatments of HDV-CH with standard or pegylated interferon alfa (peg-IFN-α) have all been unsatisfactory, leading to a sustained virological response (SVR) only in 20–30% of patients treated, faced with a poor tolerability and frequent serious adverse reactions; the addition of HBV nucleo(s)tide analogues to peg-IFN- α did not improve the rate of SVR. The improved knowledge of the HDV life cycle has allowed the development of direct acting agents towards key-points of the HDV life cycle, namely bulevirtide, lonafarnib and nucleic acid polymers. Preliminary data have shown that these drugs are more effective than interferon-based therapies, but adverse reactions are also common, which however seem toned down in combination therapy with other antivirals.

Consensus document of the Spanish Association for Study of the Liver on the treatment of hepatitis B virus infection (2020)

Hepatitis B virus (HBV) infection remains a global public health problem. HBV vaccination is the most effective tool to reduce the incidence of HBV disease. Despite there has not been new clinical developments for the treatment of chronic hepatitis B in the last few years, changing epidemiology and current insights on natural history, diagnostic tools and therapy indications make necessary an update of the former version of the consensus document of the Spanish Association for Study of the Liver on the treatment of hepatitis B infection published in 2012. The current document updates the management of chronic hepatitis B. The treatment of choice is the long-term administration of a nucleos(t)ide analogue with high barrier to resistance (entecavir, tenofovir or tenofovir alafenamide). Pegylated interferon may be an option in patients with non-advanced liver disease, but its applicability is limited due to the low efficacy and poor tolerability. All patients must be monitored for the risk of progression to advanced liver disease and development of hepatocellular carcinoma.

Viral Hepatitis Other than A, B, and C: Evaluation and Management

Viral hepatitis can cause a wide spectrum of clinical presentations from a benign form with minimal or no symptoms to acute liver failure or death. Hepatitis D coinfection and superinfection have distinct clinical courses, with the latter more likely leading to chronic infection. Management of chronic hepatitis D virus is individualized because of the paucity of treatment options and significant side effect profile of currently available treatments. Sporadic cases of hepatitis E caused by contaminated meats are becoming increasingly prevalent in immunocompromised hosts. Human herpesviruses are an important cause of disease also in immunocompromised individuals.

An update on the management of chronic hepatitis D

Hepatitis D virus (HDV) infection is associated with severe liver-related morbidity and mortality. The prevalence of HDV is rising especially among people who abuse drugs and immigrants from endemic areas. Reliable diagnostic assays with enhanced sensitivity and specificity are essential for screening at-risk populations. Until recently, interferon has been the only treatment for hepatitis D. Its efficacy is, however, limited and it is associated with significant side effects. A number of novel antiviral agents that target various stages of the HDV life cycle show promising results. They are currently in different phases of clinical development. This review focuses on the changing epidemiology, novel therapeutic agents, and updated management of chronic hepatitis delta.

Treatment of chronic hepatitis due to hepatitis B and hepatitis delta virus coinfection

An estimated 20-40 million individuals worldwide are infected with hepatitis delta virus (HDV), mostly with rapidly evolving liver disease. Therapy of chronic HDV infection remains an unmet need. To date, only interferon (IFN)-based therapy is recommended for HDV infection and response rates are unsatisfactory; in addition, many patients are intolerant to or ineligible for IFN treatment. In recent years, innovative approaches have been in development, including the following: targeting virus entry into hepatocytes; inhibition of the host enzyme farnesyltransferase by prenylation inhibitors, leading to inhibition of complete virion formation and release; blockade of hepatitis B surface antigen (HBsAg) secretion, inhibiting virus release; and IFN-lambda, which causes fewer adverse effects than IFN-alfa. Clinical trials are ongoing with encouraging preliminary results.

Chronic hepatitis delta: A state-of-the-art review and new therapies

Chronic delta hepatitis is the most severe form of viral hepatitis affecting nearly 65 million people worldwide. Individuals with this devastating illness are at higher risk for developing cirrhosis and hepatocellular carcinoma. Delta virus is a defective RNA virus that requires hepatitis B surface antigen for propagation in humans. Infection can occur in the form of a co-infection with hepatitis B, which can be self-limiting, vs superinfection in a patient with established hepatitis B infection, which often leads to chronicity in majority of cases. Current noninvasive tools to assess for advanced liver disease have limited utility in delta hepatitis. Guidelines recommend treatment with pegylated interferon, but this is limited to patients with compensated disease and is efficacious in about 30% of those treated. Due to limited treatment options, novel agents are being investigated and include entry, assembly and export inhibitors of viral particles in addition to stimulators of the host immune response. Future clinical trials should take into consideration the interaction of hepatitis B and hepatitis D as suppression of one virus can lead to the activation of the other. Also, surrogate markers of treatment efficacy have been proposed.

HBV/HDV Coinfection: A Challenge for Therapeutics

Chronic hepatitis D (CHD) results from an infection with the hepatitis B virus and hepatitis D virus (HDV). CHD is the most severe form of human viral hepatitis. Current treatment options consist of interferon alfa, which is effective only in a minority of patients. Study of HDV molecular virology has resulted in new approaches entering clinical trials, with phase-3 studies the most advanced. These include the entry inhibitor bulevirtide, the nucleic acid polymer REP 2139-Ca, the farnesyltransferase inhibitor lonafarnib, and pegylated interferon lambda. This article summarizes the available data on these emerging therapeutics.

Interferon Treatment Duration in Patients With Chronic Delta Hepatitis and its Effect on the Natural Course of the Disease

Background

Interferon is the only treatment option in chronic delta hepatitis (CDH). A CDH database (333 patients, 161 with interferon treatment history) was analyzed for effects of treatment duration on virologic response and clinical outcomes.

Methods

Ninety-nine CDH patients who received at least 6 months of interferon were selected. Maintained virologic response (MVR) was defined as hepatitis D virus RNA negative for 2 years after treatment discontinuation. Cumulative median interferon treatment duration was 24 months (range 6-126 months), with a median of 2 courses (range 1-8). Post-treatment median follow-up was 55 months (24-225 months).

Results

Thirty-five patients achieved MVR. Cumulative probability of MVR increased with treatment duration and reached 50% at 5 years. Patients with MVR were less likely to die from liver disease or develop complications compared to patients without MVR (P = .032, P = .006, respectively). Cirrhosis at baseline and no response to therapy (odds ratio 16.1 and 5.23, respectively) predicted an adverse endpoint. Hepatitis B surface antigen clearance occurred in 37% of patients with MVR.

Conclusion

Viral response to interferon increases with treatment duration and favorably affects the natural course of disease. Interferon treatment duration has to be individualized with careful post-treatment assessment.

Hepatitis D infection: from initial discovery to current investigational therapies

Hepatitis D is the most severe form of viral hepatitis associated with a more rapid progression to cirrhosis and an increased risk of hepatocellular carcinoma and mortality compared with hepatitis B mono-infection. Although once thought of as a disappearing disease, hepatitis D is now becoming recognized as a serious worldwide issue due to improvement in diagnostic testing and immigration from endemic countries. Despite these concerns, there is currently only one accepted medical therapy (pegylated-interferon-α) for the treatment of hepatitis D with less than desirable efficacy and significant side effects. Due to these reasons, many patients never undergo treatment. However, increasing knowledge about the virus and its life cycle has led to the clinical development of multiple promising new therapies that hope to alter the natural history of this disease and improve patient outcome. In this article, we will review the literature from discovery to the current investigational therapies.

New treatment options for delta virus: Is a cure in sight?

Current treatment of chronic hepatitis D viral infection with interferons is poorly tolerated and effective only in a minority of patients. Despite delta virus causing the most severe form of chronic viral hepatitis, no other treatments are available. After many years of inactivity, there is now hope for new treatment approaches for delta virus and some are likely to enter clinical practice in the near future. Four new treatment approaches are currently being evaluated in phase 2 studies. These involve the hepatocyte entry inhibitor myrcludex B, the farnesyl transferase inhibitor lonafarnib, the nucleic acid inhibitor REP 2139 Ca and pegylated interferon lambda. Results obtained so far are promising, and phase 3 studies are expected shortly. This review summarizes the available data on the efficacy and safety of these new drugs.

Treating chronic hepatitis delta: The need for surrogate markers of treatment efficacy

Chronic hepatitis delta represents the most severe form of chronic viral hepatitis. The current treatment of hepatitis delta virus (HDV) infection consists of the use of interferons and is largely unsatisfactory. Several new compounds are currently in development for the treatment of HDV infection. However, surrogate markers that can be used to develop clinical endpoints in HDV infection are not well defined. In the current manuscript, we aimed to evaluate the existing data on treatment of HDV infection and to suggest treatment goals (possible "trial endpoints") that could be used across different clinical trials.

Pathogenesis of and New Therapies for Hepatitis D

Hepatitis delta virus (HDV) infection of humans was first reported in 1977, and now it is now estimated that 15-20 million people are infected worldwide. Infection with HDV can be an acute or chronic process that occurs only in patients with an hepatitis B virus infection. Chronic HDV infection commonly results in the most rapidly progressive form of viral hepatitis; it is the chronic viral infection that is most likely to lead to cirrhosis, and it is associated with an increased risk of hepatocellular carcinoma. HDV infection is the only chronic human hepatitis virus infection without a therapy approved by the US Food and Drug Administration. Peginterferon alfa is the only recommended therapy, but it produces unsatisfactory results. We review therapeutic agents in development, designed to disrupt the HDV life cycle, that might benefit patients with this devastating disease.

Viral dominance patterns in chronic hepatitis delta determine early response to interferon alpha therapy

Chronic hepatitis D is caused by coinfection of hepatitis B and hepatitis D virus. While HDV is the dominant virus over HBV in the majority of cases, mechanisms and consequences of viral dominance are largely unknown. We aimed to investigate associations between viral dominance patterns and patients' characteristics and inflammatory features; 109 HDV-infected patients treated with PEG-IFNa-2α within the international multicentre, prospective HIDIT-2 trial were studied. Patients were classified as D- or B-dominant if the viral load of one virus exceeded that of the other virus by more than 1log₁₀ . Otherwise, no viral dominance (ND) was described. We used Luminex-based multiplex technology to study 50 soluble immune mediators (SIM) in pretreatment samples of 105 HDV RNA-positive patients. Dominance of HDV was evident in the majority (75%) of cases. While only 7% displayed B-dominance, 17% showed nondominance. D-dominance was associated with downregulation of 4 interleukins (IL-2ra, IL-13, IL-16 and IL-18) and 5 chemokines/cytokines (CTACK (CCL27), MCP-1 (CCL2), M-CSF, TRAIL and ICAM-1) while no analyte was increased. In addition, D-dominance could be linked to a delayed HDV RNA response to pegylated interferon as patients with B-dominance or nondominance showed higher early HDV RNA responses (61% at week 12) than D-dominant patients (11%; P < .001). In conclusion, this study revealed unexpected effects of viral dominance on clinical and immunological features in chronic hepatitis delta patients. Individualizing PEG-IFNa-2α treatment duration should consider viral dominance. Overall, our findings suggest an activated but exhausted IFN system in D-dominant patients.

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.

Hepatitis D, B and C virus (HDV/HBV/HCV) coinfection as a diagnostic problem and therapeutic challenge

Coinfection with hepatitis D virus (HDV) in chronic hepatitis B is associated with more rapid progression to liver cirrhosis. We present two cases of infection with hepatitis D, B and C viruses. Both male patients were primarily diagnosed as infected with hepatitis B virus (HBV) and hepatitis C virus (HCV), HBsAg-positive and anti-HCV-positive. The first patient was treated with interferon, lamivudine and pegylated interferon. A full virological and biochemical response was achieved. The second patient was treated with interferon and ribavirin, lamivudine and twice with pegylated interferon. In the ultrasound elastography progression of liver fibrosis to F4 was described. HDV infection should be considered in patients with HBV minireplication, high activity of aminotransferases and progression of liver disease despite a good virological response to anti-HBV treatment. Efficacy of interferon in HDV infection is severely limited.

Antiviral therapy of hepatitis delta virus infection - progress and challenges towards cure

Hepatitis B-/D-virus co-infection causes the most severe form of viral hepatitis, frequently leading to liver cirrhosis, hepatic decompensation and consecutive liver-related mortality. Treatment options for hepatitis delta are limited. The only recommended therapy is pegylated interferon alpha which leads to virological responses in about 25-30% of patients. However, interferon therapy is associated with frequent side-effects and late HDV RNA relapses have been described during long-term follow even in patients who were HDV RNA negative 24 weeks after the end of therapy. Thus, alternative treatment options are urgently needed. Clinical studies have been performed exploring prenylation inhibitors, viral entry inhibitors and nucleic acid polymers to block particle release. We here summarize the progress and challenges towards cure of HDV infection.

Treatment of chronic hepatitis D with the entry inhibitor myrcludex B: First results of a phase Ib/IIa study

BACKGROUND & AIMS

The therapeutic option for patients with chronic hepatitis delta virus infection (CHD) is limited to interferon alpha with rare curative outcome. Myrcludex B is a first-in-class entry inhibitor inactivating the hepatitis B virus (HBV) and hepatitis D virus (HDV) receptor sodium taurocholate co-transporting polypeptide. We report the interim results of a pilot trial on chronically infected HDV patients treated with myrcludex B, or pegylated interferon alpha (PegIFNα-2a) or their combination.

METHODS

Twenty-four patients with CHD infection were equally randomized (1:1:1) to receive myrcludex B, or PegIFNα-2a or their combination. Patients were evaluated for virological and biochemical response and tolerability of the study drugs at weeks 12 and 24.

RESULTS

Myrcludex B was well tolerated and no serious adverse event occurred. Although hepatitis B surface antigen levels remained unchanged, HDV RNA significantly declined at week 24 in all cohorts. HDV RNA became negative in two patients each in the Myrcludex B and PegIFNα-2a cohorts, and in five patients of the Myrcludex B+PegIFNα-2a cohort. ALT decreased significantly in the Myrcludex B cohort (six of eight patients), and HBV DNA was significantly reduced at week 24 in the Myrcludex B+PegIFNα-2a cohort. Virus kinetic modeling suggested a strong synergistic effect of myrcludex B and PegIFNα-2a on both HDV and HBV.

CONCLUSIONS

Myrcludex B showed a strong effect on HDV RNA serum levels and induced ALT normalization under monotherapy. Synergistic antiviral effects on HDV RNA and HBV DNA in the Myr-IFN cohort indicated a benefit of the combination of entry inhibition with PegIFNα-2a to treat CHD patients.

LAY SUMMARY

Myrcludex B is a new drug to treat hepatitis B and D infection. After 24weeks of treatment with myrcludex B and/or pegylated interferon α-2a, HDV R NA, a relevant marker for hepatitis D infection, decreased in all patients with chronic hepatitis B and D. Two of eight patients which received either myrcludex B or pegylated interferon α-2a, became negative for HDV RNA, and five of seven patients who received both drugs at the same time became negative. The drug was well tolerated.

HBsAg kinetics in chronic hepatitis D during interferon therapy: on-treatment prediction of response

BACKGROUND

Therapy of chronic hepatitis D with Interferon is successful when testing for HDV-RNA turns negative. This end-point is disputed.

AIM

To assess the role of serum hepatitis B surface antigen (HBsAg) in the clearance of HDV-RNA in pegylated interferon (Peg-IFN)-treated chronic hepatitis D (CHD).

METHODS

Sixty-two patients with CHD, treated with Peg-IFN, were considered. The patients belonged to three groups: 14 patients cleared the HBsAg and HDV-RNA (responders, R), 12 cleared the HDV-RNA remaining positive for HBsAg (partial responders, PR) and 36 cleared neither the HBsAg nor the HDV-RNA (nonresponders, NR).

RESULTS

In responders, at baseline the median value (mv) of HBsAg and HDV-RNA was 1187 and 188 663 IU/mL. By month 6 of therapy, HBsAg declined to less than 1000 IU/mL and HDV-RNA was undetectable in 12 patients. In NR, the pre-therapy median value of HBsAg and HDV viremia was 6577 and 676 319 IU/mL. There was no significant reduction of antigen at month 6; after a decline, HDV-RNA rebounded to baseline levels. In PR, the median value of baseline HBsAg was 7031 IU/mL; it declined at month 6 in the majority. HDV-RNA progressively declined from an initial median value of 171 405 IU/mL. HBsAg <1000 IU/mL at month 6 discriminated responders and PR from NR (P < 0.001). By ROC curve, the threshold of 0.105 log reduction of HBsAg associated with 1.610 log reduction of HDV-RNA from baseline to month 6 predicted the clearance of this marker.

CONCLUSIONS

A reduction of serum HBsAg is mandatory for the definitive clearance of the HDV-RNA. Quantitative HBsAg may predict the long-term response to Peg-IFN therapy and provide a guide to prolong or stop treatment.

New antiviral targets for innovative treatment concepts for hepatitis B virus and hepatitis delta virus

Current therapies of chronic hepatitis B (CHB) remain limited to pegylated-interferon-alpha (PegIFN-α) or any of the five approved nucleos(t)ide analogues (NUC) treatments. While viral suppression can be achieved in the majority of patients with the high-barrier-to-resistance new-generation of NUC, i.e. entecavir and tenofovir, HBsAg loss is achieved by PegIFN-α and/or NUC in only 10% of patients, after a 5-year follow-up. Attempts to improve the response by administering two different NUC or a combination of NUC and PegIFN-α have not provided a dramatic increase in the rate of functional cure. Because of this and the need of long-term NUC administration, there is a renewed interest regarding the understanding of various steps of the HBV replication cycle, as well as specific virus-host cell interactions, in order to define new targets and develop new antiviral drugs. This includes a direct inhibition of viral replication with entry inhibitors, drugs targeting cccDNA, siRNA targeting viral transcripts, capsid assembly modulators, and approaches targeting the secretion of viral envelope proteins. Restoration of immune responses is a complementary approach. The restoration of innate immunity against HBV can be achieved, with TLR agonists or specific antiviral cytokine delivery. Restoration of adaptive immunity may be achieved with inhibitors of negative checkpoint regulators, therapeutic vaccines, or autologous transfer of engineered HBV-specific T cells. Novel targets and compounds will readily be evaluated using both relevant and novel in vitro and in vivo models of HBV infection. The addition of one or several new drugs to current therapies should offer the prospect of a markedly improved response to treatments and an increased rate of functional cure. This should lead to a reduced risk of antiviral drug resistance, and to a decreased incidence of cirrhosis and hepatocellular carcinoma (HCC).

Treatment of hepatitis delta virus genotype 3 infection with peg-interferon and entecavir

OBJECTIVES

Hepatitis delta virus (HDV) is recognized as the most pathogenic and infectious among the hepatotropic viruses. Studies on the treatment of HDV have predominantly included European patients and carriers of genotype 1 (HDV-1) in their clinical protocols. For the Amazon region, data show that infected individuals have mainly Native American ancestry and that >90% of HDV carriers have the genotype 3 (HDV-3). Thus combined therapy clinical protocols do not adequately address the treatment of these patients.

METHODS

A prospective, non-randomized study was conducted in which 22 patients received 180μg of pegylated interferon alpha 2a (PEG-IFN) plus entecavir at a dose of 0.5mg for 48 weeks, with a subsequent 24-week follow-up. Throughout treatment, the patients were monitored for biochemical responses and the kinetics of hepatitis B virus (HBV) and HDV viral loads.

RESULTS

Of the 22 patients treated, 15 presented normal alanine aminotransferase values at the end of treatment (p=0.002). At week 24 of treatment, 86.4% of the patients did not present detectable HDV-RNA; at week 48, the rate of negative patients increased to >95% and remained the same after 6 months. With regard to HBV, only two patients (9%) still presented detectable HBV genetic material at the end of treatment, suggesting the effectiveness of combined therapy in combating the two viruses.

CONCLUSIONS

These findings support the use of this effective therapeutic protocol for HDV-3 in patients of non-European ethnicity and suggest a possible 'easy to treat' variant when compared to HDV-1.