Late HDV RNA relapse after peginterferon alpha-based therapy of chronic hepatitis delta

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.

Effect of variants in LGP2 on MDA5-mediated activation of interferon response and suppression of hepatitis D virus replication

BACKGROUND & AIMS

Retinoic acid inducible gene I (RIG-I)-like receptors (RLRs), including RIG-I, melanoma differentiation-associated protein 5 (MDA5), and laboratory of genetics and physiology 2 (LGP2), sense viral RNA to induce the antiviral interferon (IFN) response. LGP2, unable to activate the IFN response itself, modulates RIG-I and MDA5 signalling. HDV, a small RNA virus causing the most severe form of viral hepatitis, is sensed by MDA5. The mechanism underlying IFN induction and its effect on HDV replication is unclear. Here, we aimed to unveil the role of LGP2 and clinically relevant variants thereof in these processes.

METHODS

RLRs were depleted in HDV susceptible HepaRG^NTCP cells and primary human hepatocytes. Cells were reconstituted to express different LGP2 versions. HDV and IFN markers were quantified in a time-resolved manner. Interaction studies among LGP2, MDA5, and RNA were performed by pull-down assays.

RESULTS

LGP2 is essential for the MDA5-mediated IFN response induced upon HDV infection. This induction requires both RNA binding and ATPase activities of LGP2. The IFN response only moderately reduced HDV replication in resting cells but profoundly suppressed cell division-mediated HDV spread. An LGP2 variant (Q425R), predominating in Africans who develop less severe chronic hepatitis D, mediated detectably higher basal and faster HDV-induced IFN response as well as stronger HDV suppression. Mechanistically, LGP2 RNA binding was a prerequisite for the formation of stable MDA5-RNA complexes. MDA5 binding to RNA was enhanced by the Q425R LGP2 variant.

CONCLUSIONS

LGP2 is essential to mount an antiviral IFN response induced by HDV and stabilises MDA5-RNA interaction required for downstream signalling. The natural Q425R LGP2 is a gain-of-function variant and might contribute to an attenuated course of hepatitis D.

IMPACT AND IMPLICATIONS

HDV is the causative pathogen of chronic hepatitis D, a severe form of viral hepatitis that can lead to cirrhosis and hepatocellular carcinoma. Upon infection, the human immune system senses HDV and mounts an antiviral interferon (IFN) response. Here, we demonstrate that the immune sensor LGP2 cooperates with MDA5 to mount an IFN response that represses HDV replication. We mapped LGP2 determinants required for IFN system activation and characterised several natural genetic variants of LGP2. One of them reported to predominate in sub-Saharan Africans can accelerate HDV-induced IFN responses, arguing that genetic determinants, possibly including LGP2, might contribute to slower disease progression in this population. Our results will hopefully prompt further studies on genetic variations in LGP2 and other components of the innate immune sensing system, including assessments of their possible impact on the course of viral infection.

Beyond bulevirtide: Alternative therapeutic options for the management of hepatitis delta virus

Hepatitis delta virus (HDV) is a small RNA virus which needs Hepatitis B Surface Antigen for its envelope, for entry into hepatocytes and secretion. HDV chronic infection affects around 12 million people worldwide. HDV infection is believed to be the most severe form of viral hepatitis, with a high risk of developing cirrhosis and hepatocellular carcinoma. Pegylated interferons has been used and recommended by guidelines, although not approved, with low efficacy and poor tolerability. Bulevirtide (entry inhibitor) has been recently conditionally approved by the European Medicines Agency. These treatments have many advantages, but they have also limitations since there are non-responders to these previous therapies. There is an urgent need to develop new drugs. In this article, we review antiviral treatments under development for HDV chronic infection (except bulevirtide reviewed in a specific article), including those in the HBV cure programme, outlining their respective mechanisms-of-action.

Bulevirtide with or without pegIFNα for patients with compensated chronic hepatitis delta: From clinical trials to real-world studies

Chronic hepatitis D (CHD) is the most severe form of viral hepatitis, characterised by the greatest increase in risk of cirrhosis, hepatic decompensation and hepatocellular carcinoma. Pegylated-interferon-α (pegIFNα), the only off-label therapeutic option, has been available for the last 30 years but is associated with suboptimal response rates and poor tolerability. Among the new treatment strategies under clinical evaluation, the entry inhibitor bulevirtide (BLV) is the only one that has received conditional approval from the European Medicines Agency (EMA); approval was granted in July 2020 for the treatment of adult patients with compensated CHD at a dose of 2 mg daily. Phase II studies and the week 24 interim analysis of a phase III study demonstrated the efficacy and safety of this treatment as a monotherapy or combined with pegIFNα. This favourable profile has been confirmed by recent real-world studies performed in Europe. As a long-term monotherapy, BLV has been successfully used to treat patients with advanced compensated cirrhosis. These encouraging yet preliminary findings must be viewed with caution as many critical issues related to this new antiviral strategy are still poorly understood, as summarised in this review. While waiting for new anti-HBV and anti-HDV drugs to become available for combination studies, BLV treatment is currently the only available anti-HDV therapeutic option that might improve the long-term prognosis of difficult-to-manage patients with CHD.

Chronic Viral Hepatitis in Elite Athletes: Approaches to Risk Assessment, Prevention and Management

Elite athletes who participate in contact sports are at risk of bleeding injuries, leading to transmission of blood-borne viruses including hepatitis type B, C and D (HBV, HCV and HDV) capable of causing chronic liver disease, liver failure and liver cancer. In view of the significant advances in the viral hepatitis field over the past decade, more structured approaches should be in place to screen for and manage viral hepatitis in elite athletes. HBV status should be assessed in all elite athletes, and those infected should receive nucleos(t)ide analogues for viral suppression, while uninfected individuals should receive HBV vaccination. The all-oral direct acting antivirals for HCV are highly effective and safe, thus the remaining challenge with hepatitis C is case identification and linkage to care. HDV is only found in HBV-infected individuals, which is characterized by rapid disease progression and higher rates of cirrhosis and liver cancer in infected subjects. Pegylated interferon was the mainstay of treatment for HDV infection until bulevirtide, a viral entry inhibitor, was recently approved by the European Union (EMA) and FDA in America, while multiple novel therapies are already in clinical trials as part of the HBV cure program. Overall, awareness of chronic viral hepatitis in athletes should be improved. Prevention remains the cornerstone of the management of viral hepatitis in sport coupled with rigorous disease assessment in infected individuals, and antiviral therapy where indicated.

Hepatitis D virus-induced interferon response and administered interferons control cell division-mediated virus spread

BACKGROUND & AIMS

Besides HBV-dependent de novo infection, cell division-mediated spread contributes to HDV persistence and dampens the effect of antivirals that abrogate de novo infection. Nonetheless, the combination of these antivirals with interferons (IFNs) showed strong synergism in recent clinical trials, implying a complementary mode-of-action of IFNs. Therefore, we investigated the effect of IFN response on cell division-mediated HDV spread.

METHODS

Cells infected with HDV were passaged to undergo cell division. The effect of the IFN response was evaluated by blocking HDV-induced IFN activation, by applying different IFN treatment regimens, and by adjusting HDV infection doses.

RESULTS

Cell division-mediated HDV spread was highly efficient following infection of HuH7^NTCP cells (defective in IFN production), but profoundly restricted in infected IFN-competent HepaRG^NTCP cells. Treatment with IFN-α/-λ1 inhibited HDV spread in dividing HuH7^NTCP cells, but exhibited a marginal effect on HDV replication in resting cells. Blocking the HDV-induced IFN response with the JAK1/2 inhibitor ruxolitinib or knocking down MDA5 augmented HDV spread in dividing HepaRG^NTCP cells. The virus-induced IFN response also destabilized HDV RNA in dividing cells. Moreover, the effect of exogenous IFNs on cell division-mediated HDV spread was more pronounced at low multiplicities of infection with weak virus-induced IFN responses.

CONCLUSIONS

Both HDV-induced IFN response and exogenous IFN treatment suppress cell division-mediated HDV spread, presumably through acceleration of HDV RNA decay. Our findings demonstrate a novel mode-of-action of IFN, explain the more pronounced effect of IFN therapy in patients with lower HDV serum RNA levels, and provide insights for the development of combination therapies.

LAY SUMMARY

Chronic hepatitis D is a major health problem. The causative pathogen hepatitis D virus (HDV) can propagate through viral particle-mediated infection and the division of infected cells. Although viral particle-dependent infection can be blocked by recently developed drugs, therapies addressing the cell division route have not been reported. Taking advantage of relevant cell culture models, we demonstrate that the widely used immune modulator interferon can efficiently suppress HDV spread through cell division. This work unveils a new function of interferon and sheds light on potentially curative combination therapies.

Hepatitis D virus (HDV): investigational therapeutic agents in clinical trials

INTRODUCTION

Chronic Hepatitis D virus (HDV) infection is a global disease leading to rapidly progressive liver disease with increased liver-related mortality and hepatocellular carcinoma. Therapies are minimally effective; however, an increased understanding of the HDV lifecycle has provided new potential drug targets. Thus, there is a growing number of investigational therapeutics under exploration for HDV with the potential for successful viral eradication.

AREAS COVERED

This review discusses the clinical impact of HDV infection and offers an in-depth look at the HDV life cycle. The authors examine current and new drug targets and the investigational therapies in clinical trials. The search strategy was based on PubMed database and clinicaltrials.gov which highlight the most up-to-date aspects of investigational therapies for chronic HDV infection.

Novel prime-boost immune-based therapy inhibiting both hepatitis B and D virus infections

OBJECTIVE

Chronic HBV/HDV infections are a major cause of liver cancer. Current treatments can only rarely eliminate HBV and HDV. Our previously developed preS1-HDAg immunotherapy could induce neutralising antibodies to HBV in vivo and raise HBV/HDV-specific T-cells. Here, we further investigate if a heterologous prime-boost strategy can circumvent T-cell tolerance and preclude HDV superinfection in vivo.

DESIGN

A DNA prime-protein boost strategy was evaluated for immunogenicity in mice and rabbits. Its ability to circumvent T-cell tolerance was assessed in immunocompetent hepatitis B surface antigen (HBsAg)-transgenic mice. Neutralisation of HBV and HDV was evaluated both in vitro and in immunodeficient human-liver chimeric mice upon adoptive transfer.

RESULTS

The prime-boost strategy elicits robust HBV/HDV-specific T-cells and preS1-antibodies that can effectively prevent HBV and HDV (co-)infection in vitro and in vivo. In a mouse model representing the chronic HBsAg carrier state, active immunisation primes high levels of preS1-antibodies and HDAg-specific T-cells. Moreover, transfer of vaccine-induced antibodies completely protects HBV-infected human-liver chimeric mice from HDV superinfection.

CONCLUSION

The herein described preS1-HDAg immunotherapy is shown to be immunogenic and vaccine-induced antibodies are highly effective at preventing HBV and HDV (super)infection both in vitro and in vivo. Our vaccine can complement current and future therapies for the control of chronic HBV and HDV infection.

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.

Novel Pegylated Interferon for the Treatment of Chronic Viral Hepatitis

Ropeginterferon alfa-2b is a novel mono-pegylated and extra-long-acting interferon, being developed for the treatment of myeloproliferative neoplasm (MPN) and chronic viral hepatitis. It has a favorable pharmacokinetic profile and less frequent dosing schedule, i.e., once every two to four weeks, compared to conventional pegylated interferon products, which have multiple isomers and are administered weekly. It was approved for the long-term treatment of polycythemia vera, an MPN, and has been included in the NCCN clinical practice guidelines for this indication. Ropeginterferon alfa-2b has demonstrated efficacy and showed a favorable safety profile for the treatment of chronic viral hepatitis in several clinical studies. In this article, we review its pharmacokinetics and available clinical data and suggest that ropeginterferon alfa-2b administered once every two weeks can serve as a new treatment option for patients with chronic viral hepatitis, including chronic hepatitis B, C, and D.

Australian consensus recommendations for the management of hepatitis B

INTRODUCTION

The prevalence of hepatitis B virus (HBV) infection in Australia is nearly 1%. In certain well defined groups the prevalence is far greater, yet an estimated 27% of people living with HBV infection remain undiagnosed. Appropriate screening improves detection, increases opportunity for treatment, and ultimately reduces the significant morbidity and mortality associated with the development of liver fibrosis and hepatocellular carcinoma (HCC).

MAIN RECOMMENDATIONS

This statement highlights important aspects of HBV infection management in Australia. There have been recent changes in nomenclature and understanding of natural history, as well as a newly defined upper limit of normal for liver tests that determine phase classification and threshold for antiviral treatment. As the main burden of hepatitis B in Australia is within migrant and Indigenous communities, early identification and management of people living with hepatitis B is essential to prevent adverse outcomes including liver cancer and cirrhosis.

CHANGE IN MANAGEMENT AS A RESULT OF THIS GUIDELINE

These recommendations aim to raise awareness of the current management of hepatitis B in Australia. Critically, the timely identification of individuals living with hepatitis B, and where appropriate, commencement of antiviral therapy, can prevent the development of cirrhosis, HCC and mother-to-child transmission as well as hepatitis B reactivation in immunocompromised individuals. Recognising patient and viral factors that predispose to the development of cirrhosis and HCC will enable clinicians to risk-stratify and appropriately implement surveillance strategies to prevent these complications of hepatitis B.

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.

Review article: emerging insights into the immunopathology, clinical and therapeutic aspects of hepatitis delta virus

BACKGROUND

Hepatitis delta virus (HDV), which causes the most severe form of viral hepatitis, is an obligated hepatitis B (HBV) satellite virus that can either infect naïve subjects simultaneously with HBV (co-infection), or chronically infect HBV carriers (super-infection). An estimated 12 million people are infected by HDV worldwide.

AIMS

To summarise the most relevant aspects of the molecular biology of HDV, and to discuss the latest understanding of the induced pathology, interactions with the immune system, as well as both approved and investigational treatment options.

METHODS

References for this review were identified through searches of PubMed with the terms "HDV" "viral hepatitis" "co-infection" and "super-infection," published between 1980 and October 2021 RESULTS: The limited access to the HDV-infected liver has hampered the investigation of the intrahepatic compartment and our understanding of the mechanisms of HDV pathogenesis. In the absence of standardised and sensitive diagnostic tools, HDV is often underdiagnosed and owing to its strong dependence on host cellular factors, the development of direct antiviral agents has been challenging. New therapeutic agents targeting different steps of the viral cycle have recently been investigated, among which bulevirtide (which was conditionally approved by EMA in July 2020) and lonafarnib; both drugs having received orphan drug designation from both the EMA and FDA.

CONCLUSIONS

The HBV cure programme potentially offers a unique opportunity to enhance HDV treatment strategies. In addition, a more comprehensive analysis of the intrahepatic compartment is mandated to better understand any liver-confined interaction of HDV with the host immune system.

Viral Hepatitis - The Road Traveled and the Journey Remaining

Hepatitis is defined as inflammation of the liver and is commonly due to infection with The hepatotropic viruses - hepatitis A, B, C, D and E. Hepatitis carries one of the highest disease burdens globally and has caused significant morbidity and mortality among different patient populations. Clinical presentation varies from asymptomatic or acute flu-like illness to acute liver failure or chronic liver disease, characterized by jaundice, hepatomegaly and ascites among many other signs. Eventually, this can lead to fibrosis (cirrhosis) of the liver parenchyma and carries a risk of development into hepatocellular carcinoma. Hepatitis B and C are most notorious for causing liver cirrhosis; in 2019, an estimated 296 million people worldwide had chronic hepatitis B infection and 58 million are currently estimated to have chronic hepatitis C, with 1.5 million new infections of both hepatitis B and C, occurring annually. With the help of latest serological biomarkers and viral nucleic acid amplification tests, it has become rather simple to efficiently screen, diagnose and monitor patients with hepatitis, and to commence with appropriate antiviral treatment. More importantly, the development of vaccinations against some of these viruses has greatly helped to curb the infection rates. Whilst there has been exceptional progress over the years in the management of viral hepatitis, many hurdles still remain which must be addressed in order to proceed towards a hepatitis-free world. This review will shed light on the origin and discovery of the hepatitis viruses, the global epidemiology and clinical symptoms, diagnostic modalities, currently available treatment options, the importance of prevention, and the journey needed to move forward towards the eradication of its global disease burden.

HBcrAg Levels Are Associated With Virological Response to Treatment With Interferon in Patients With Hepatitis Delta

Standard treatment of hepatitis delta virus (HDV) infection remains pegylated-interferon alfa (peg-IFNα) in most centers, which is not only associated with rather low efficacy but several adverse events. Hepatitis B core-related antigen (HBcrAg) is linked to intrahepatic covalently closed circular DNA levels and has previously been suggested as response predictor in IFN-based treatment of hepatitis B virus (HBV) mono-infection. This study aimed to investigate the value of HBcrAg in the management of patients with HBV/HDV co-infection undergoing peg-IFNα treatment. The Hep-Net-International-Delta-Hepatitis-Intervention Trial-2 study included 120 patients co-infected with HBV/HDV. Patients were treated for 96 weeks with peg-IFNα and either tenofovir or placebo. Ninety-nine patients with HDV-RNA results 24 weeks after end of treatment (FU24) were included in this analysis, of whom 32 patients (32.3%) had undetectable HDV RNA at FU24. HBcrAg was measured at baseline, week 12, 24, 48, 96, and FU24. HBcrAg levels showed no significant correlation with HDV RNA but were significantly linked to treatment outcome. HBcrAg levels < 4.5 log IU/mL at baseline, week 24, and week 48 had high negative predictive value (NPV) for achieving undetectable HDV RNA at FU24 (81.8%, 87.1% and 95.0%, respectively). Similarly, HBcrAg levels at week 96 were significantly higher in patients with viral relapse until FU24 (3.0 vs. 3.63 log IU/mL; P = 0.0089). Baseline, week 24, and week 48 HBcrAg levels were also associated with the likelihood of achieving HBsAg level < 100 IU/mL at FU24 (HBcrAg < 3.0 log IU/mL: NPV 91.7%, 90.4% and 92.3%, respectively). Test statistics improved when combining HBcrAg with additional viral and clinical parameters. Conclusion: HBcrAg is linked to treatment response to peg-IFNα in patients with HBV/HDV co-infection and could be a promising marker to determine treatment futility.

Combination of Novel Therapies for HDV

Treatment options for HDV have been limited to interferon alfa-based therapies with its poor efficacy to side effects ratio. Several novel therapies have now advanced into the clinic. As they each have a different mechanism of action, there is the potential for combination therapy. Here we review how studying the HDV life cycle has led to the development of these novel therapies, the key developments leading to, and the details of, the first combination study of novel anti-HDV therapies, and suggest what additional combinations of novel therapies can be anticipated as we enter this exciting new area of HDV treatments.

Adaptive Immune Responses, Immune Escape and Immune-Mediated Pathogenesis during HDV Infection

The hepatitis delta virus (HDV) is the smallest known human virus, yet it causes great harm to patients co-infected with hepatitis B virus (HBV). As a satellite virus of HBV, HDV requires the surface antigen of HBV (HBsAg) for sufficient viral packaging and spread. The special circumstance of co-infection, albeit only one partner depends on the other, raises many virological, immunological, and pathophysiological questions. In the last years, breakthroughs were made in understanding the adaptive immune response, in particular, virus-specific CD4+ and CD8+ T cells, in self-limited versus persistent HBV/HDV co-infection. Indeed, the mechanisms of CD8+ T cell failure in persistent HBV/HDV co-infection include viral escape and T cell exhaustion, and mimic those in other persistent human viral infections, such as hepatitis C virus (HCV), human immunodeficiency virus (HIV), and HBV mono-infection. However, compared to these larger viruses, the small HDV has perfectly adapted to evade recognition by CD8+ T cells restricted by common human leukocyte antigen (HLA) class I alleles. Furthermore, accelerated progression towards liver cirrhosis in persistent HBV/HDV co-infection was attributed to an increased immune-mediated pathology, either caused by innate pathways initiated by the interferon (IFN) system or triggered by misguided and dysfunctional T cells. These new insights into HDV-specific adaptive immunity will be discussed in this review and put into context with known well-described aspects in HBV, HCV, and HIV infections.

A Rapid Point-of-Care Test for the Serodiagnosis of Hepatitis Delta Virus Infection

Hepatitis Delta virus (HDV) is a satellite of the Hepatitis B virus (HBV) and causes severe liver disease. The estimated prevalence of 15-20 million infected people worldwide may be underestimated as international diagnostic guidelines are not routinely followed. Possible reasons for this include the limited awareness among healthcare providers, the requirement for costly equipment and specialized training, and a lack of access to reliable tests in regions with poor medical infrastructure. In this study, we developed an HDV rapid test for the detection of antibodies against the hepatitis delta antigen (anti-HDV) in serum and plasma. The test is based on a novel recombinant large hepatitis delta antigen that can detect anti-HDV in a concentration-dependent manner with pan-genotypic activity across all known HDV genotypes. We evaluated the performance of this test on a cohort of 474 patient samples and found that it has a sensitivity of 94.6% (314/332) and a specificity of 100% (142/142) when compared to a diagnostic gold-standard ELISA. It also works robustly for a broad range of anti-HDV titers. We anticipate this novel HDV rapid test to be an important tool for epidemiological studies and clinical diagnostics, especially in regions that currently lack access to reliable HDV testing.

New Treatments for Chronic Hepatitis B Virus/Hepatitis D Virus Infection

Chronic hepatitis D virus (HDV) infection is the most severe form of viral hepatitis with high rates of end-stage liver disease and hepatocellular carcinoma. Therefore, effective antiviral treatment strategies are needed desperately. Until recently, antiviral treatment was limited to pegylated interferon-alpha. With the conditional approval of the entry inhibitor bulevirtide by the European Medicines Agency, new treatment options are now available. In addition, multiple other antiviral compounds are currently tested in clinical phase II and III trials and represent promising agents for the treatment of chronic HDV infection.

Clinical establishment of a laboratory developed quantitative HDV PCR assay on the cobas6800 high-throughput system

Background & Aims

Currently available HDV PCR assays are characterized by considerable run-to-run and inter-laboratory variability. Hence, we established a quantitative reverse transcription real-time PCR (RT-qPCR) assay on the open channel of a fully automated PCR platform (cobas6800, Roche) offering improved consistency and reliability.

Methods

A primer/probe-set targeting a highly conserved region upstream of the HDV antigen was adapted for use on the cobas6800. The lower limit of detection (LLOD) was determined using a dilution panel of the HDV WHO standard (n = 21/dilution). Linearity and inclusivity were tested by preparing 10-fold dilution series of cell culture-derived virus (genotype [GT]1-8; n = 5/dilution). Patient samples containing a variety of bloodborne viral pathogens were tested to confirm exclusivity (n = 60).

Results

The LLOD of the HDV utility-channel (HDV_UTC) assay was determined as 3.86 IU/ml (95% CI 2.95-5.05 IU/ml) with a linear range from 10-10ˆ8 IU/ml (GT1). Linear relationships were observed for all HDV GTs with slopes ranging from -3.481 to -4.134 cycles/log and R² from 0.918 to 0.994. Inter-run and intra-run variability were 0.3 and 0.6 Ct (3xLLOD), respectively. No false-positive results were observed. To evaluate clinical performance, 110 serum samples of anti-HDV-Ab+ patients were analyzed using the HDV_UTC and CE-IVD RoboGene assays. 58/110 and 49/110 samples were concordant positive or negative, respectively (overall agreement 97.3%). Quantitative comparison demonstrated a strong correlation (R² 0.8733; 95% CI 0.8914-0.9609; p value <0.0001).

Conclusion

The use of highly automated, sample-to-result solutions for molecular diagnostics holds many inherent benefits over manual workflows, including improved reliability, reproducibility and dynamic scaling of testing capacity. The assay we established showed excellent analytical and clinical performance, with inclusivity for all HDV GTs and a limit of quantification of 10 IU/ml, making it a sensitive new tool for HDV screening and viral load monitoring.

Lay summary

The hepatitis delta virus (HDV) causes a severe form of inflammation in the liver. We developed a tool for molecular diagnostics, a polymerase chain reaction HDV assay that showed great performance. It can be used to improve diagnosis of HDV, as well as for monitoring treatment responses. The assay allows for quantification of the virus in the tested samples and is performed on a fully automated platform (cobas6800), which provides various benefits including less hands-on time and excellent comparability of test results.

Can Interferon therapy change natural course of Hepatitis Delta infection, A clinical and pathological study

Introduction: Chronic delta hepatitis (CDH) has a worser outcome than other viral hepatitis. High dose, long-term Interferon-α (IFNα) is the approved treatment and may ameliorate course. We evaluated long-term histological outcomes of CDH patients treated with IFNα. Method: Histologically proved non-cirrhotic CDH patients treated with high dose IFNα for at least 1 year were grouped as cirrhotic and non-cirrhotic at the end of treatment. Non-cirrhotic patients had also post-treatment liver biopsies. Patients were grouped as histologically responsive and non-responsive regarding fibrosis status. Histological, virological and biochemical courses were analyzed. Results: 48 patients were treated with IFNα (conventional and/or pegylated) for median 24 months with a post-treatment follow-up of 5 years. During the follow-up, cirrhosis developed in 24 patients, 5 of whom were decompensated. There was no difference between pre- and post-treatment fibrosis scores of 24 non-cirrhotic patients at the end of follow-up. Among patients; 13% (n:6) had decreased, 21%(n:10) had steady and 16% (n:8) had increased fibrosis scores. Persistent viral response (PVR) was achieved in 16 patients (33%). 20% of entire group was histologically responsive (decreasing or steady fibrosis scores with improved necro-inflammatory score) while near 80% had histological progression/cirrhosis. PVR was significantly associated with histological response. Conclusions: Long-term natural course of patients who were treated with high dose IFNα for at least one year was evaluated clinically and histologically. Despite the association of PVR with histological response, IFNα treatment didn't change the natural course of CDH, clinical and histological progression continued in two-thirds of the cases despite treatment.

Asociación Mexicana de Hepatología A.C. Clinical guideline on hepatitis B

Hepatitis B virus (HBV) infection continues to be a worldwide public health problem. In Mexico, at least three million adults are estimated to have acquired hepatitis B (total hepatitis B core antibody [anti-HBc]-positive), and of those, 300,000 active carriers (hepatitis B surface antigen [HBsAg]-positive) could require treatment. Because HBV is preventable through vaccination, its universal application should be emphasized. HBV infection is a major risk factor for developing hepatocellular carcinoma. Semi-annual liver ultrasound and serum alpha-fetoprotein testing favor early detection of that cancer and should be carried out in all patients with chronic HBV infection, regardless of the presence of advanced fibrosis or cirrhosis. Currently, nucleoside/nucleotide analogues that have a high barrier to resistance are the first-line therapies.

Hepatitis D virus in 2021: virology, immunology and new treatment approaches for a difficult-to-treat disease

Approximately 5% of individuals infected with hepatitis B virus (HBV) are coinfected with hepatitis D virus (HDV). Chronic HBV/HDV coinfection is associated with an unfavourable outcome, with many patients developing liver cirrhosis, liver failure and eventually hepatocellular carcinoma within 5-10 years. The identification of the HBV/HDV receptor and the development of novel in vitro and animal infection models allowed a more detailed study of the HDV life cycle in recent years, facilitating the development of specific antiviral drugs. The characterisation of HDV-specific CD4+ and CD8+T cell epitopes in untreated and treated patients also permitted a more precise understanding of HDV immunobiology and possibly paves the way for immunotherapeutic strategies to support upcoming specific therapies targeting viral or host factors. Pegylated interferon-α has been used for treating HDV patients for the last 30 years with only limited sustained responses. Here we describe novel treatment options with regard to their mode of action and their clinical effectiveness. Of those, the entry-inhibitor bulevirtide (formerly known as myrcludex B) received conditional marketing authorisation in the European Union (EU) in 2020 (Hepcludex). One additional drug, the prenylation inhibitor lonafarnib, is currently under investigation in phase III clinical trials. Other treatment strategies aim at targeting hepatitis B surface antigen, including the nucleic acid polymer REP2139Ca. These recent advances in HDV virology, immunology and treatment are important steps to make HDV a less difficult-to-treat virus and will be discussed.

Asociación Mexicana de Hepatología A.C. Clinical guideline on hepatitis B

Hepatitis B virus (HBV) infection continues to be a worldwide public health problem. In Mexico, at least three million adults are estimated to have acquired hepatitis B (total hepatitis B core antibody [anti-HBc]-positive), and of those, 300,000 active carriers (hepatitis B surface antigen [HBsAg]-positive) could require treatment. Because HBV is preventable through vaccination, its universal application should be emphasized. HBV infection is a major risk factor for developing hepatocellular carcinoma. Semi-annual liver ultrasound and serum alpha-fetoprotein testing favor early detection of that cancer and should be carried out in all patients with chronic HBV infection, regardless of the presence of advanced fibrosis or cirrhosis. Currently, nucleoside/nucleotide analogues that have a high barrier to resistance are the first-line therapies.

Ropeginterferon alfa-2b in patients with genotype 1 chronic hepatitis C: Pharmacokinetics, safety, and preliminary efficacy

BACKGROUND AND AIM

Ropeginterferon alfa-2b (P1101) is a novel long-acting mono-PEGylated recombinant proline interferon (IFN) conjugated to a 40 kDa branched polyethylene glycol (PEG) chain at its N-terminus, allowing every-two-week injection. It received European Medicines Agency and Taiwan marketing authorization for the treatment of polycythemia vera in 2019 and 2020, respectively. This phase 2 study aimed to evaluate the pharmacokinetics, safety, and preliminary efficacy of ropeginterferon alfa-2b as compared with PEG-IFN-α2a in patients with chronic hepatitis C virus genotype 1 infection.

METHODS

One hundred six treatment naive patients were enrolled in this phase 2 study and randomized to four treatment groups: subcutaneous weekly PEG-IFN-α2a 180 μg (group 1), weekly ropeginterferon alfa-2b 180 μg (group 2), weekly ropeginterferon alfa-2b 270 μg (group 3), or biweekly ropeginterferon alfa-2b 450 μg (group 4) plus ribavirin for 48 weeks.

RESULTS

After multiple weekly administration, serum exposure (AUC0-τ) in ropeginterferon alfa-2b 180 μg was approximately 41% greater and the accumulation ratio of 2-fold greater than PEG-IFN-α2a 180 μg. The incidences of flu-like symptoms were 66.7% (18/27), 53.3% (16/30), 55.0% (11/20), and 48.3% (14/29), anxiety were 14.8% (4/27), 6.7% (2/30), 0%, and 0%, and depression were 25.9% (7/27), 13.3% (4/30), 0%, and 3.4% (1/29), for groups 1-4, respectively. Two grade 2 of 3 depression were noted in PEG-IFN-α2a arm, but none in ropeginterferon arms. The SVR24 rates were 77.8% (21/27), 66.7% (20/30), 80% (16/20), and 69% (20/29), respectively.

CONCLUSIONS

Ropeginterferon alfa-2b showed longer effective half-life and superior safety profile than PEG-IFN-α2a. Biweekly injection of ropeginterferon alfa-2b will be studied in larger viral hepatitis patient population.

One-quarter of chronic hepatitis D patients reach HDV-RNA decline or undetectability during the natural course of the disease

BACKGROUND

Spontaneous HDV-RNA fluctuations, assessed by nonstandardised in-house assays, have been reported during the course of chronic hepatitis delta (CHD).

AIMS

To evaluate changes in serum HDV-RNA concentrations in untreated CHD patients and correlate these changes with other HBV markers.

METHODS

A total of 323 consecutive serum samples from 56 CHD patients (detectable HDV-RNA) followed for >3 years were retested for HDV-RNA levels by a sensitive technique using the first WHO international HDV-RNA standard. Quantitative HBsAg, HBV-DNA, and HBV-RNA were also determined.

RESULTS

Most participants were male, middle-aged, white European, and HBeAg-negative (82%). Almost half had liver cirrhosis and 64% were receiving nucleos(t)ide analogues. At inclusion, median-HDV-RNA was 5.3 (4.2-6.5) log10 IU/mL, HBsAg 4.0 (3.5-4.3) log10 IU/mL, and HBV-DNA 1.6 (1.0-2.6) log10 IU/mL; ALT values were normal in 13 (23%). During a mean follow-up of 5.6 (3-16) years, 14 (25%) showed ≥2log10 HDV-RNA decline, including 11 (20%) who spontaneously achieved undetectable HDV-RNA. Four patients (7%) lost HBsAg, with undetectable HDV-RNA. The remaining 42 (75%) had persistently detectable HDV-RNA. During follow-up, patients with a ≥2log10 HDV-RNA decline showed a greater HBsAg drop (-0.7 ± 1.1 vs -0.09 ± 0.9 log IU/mL; P = 0.039) than those with a <2 log10 HDV-RNA decline. Overall, ALT and HBV-DNA levels decreased over time. There were no differences in clinical outcomes between groups.

CONCLUSIONS

One-quarter of untreated CHD patients showed a ≥2log10 decline in HDV-RNA and 20% reached HDV-RNA undetectability during a mean follow-up of 5.6 years. The decline was associated with ALT decrease. These findings have implications for designing new therapies for CHD.

Durable virological response and functional cure of chronic hepatitis D after long-term peginterferon therapy

BACKGROUND

Hepatitis delta virus (HDV) infection is the most aggressive form of chronic viral hepatitis. Response rates to therapy with 1- to 2-year courses of pegylated interferon alpha (peginterferon) treatment are suboptimal.

AIMS

To evaluate the long-term outcomes of patients with chronic hepatitis D after an extended course of peginterferon.

METHODS

Patients were followed after completion of trial NCT00023322 and classified based on virological response defined as loss of detectable serum HDV RNA at last follow-up. During extended follow-up, survival and liver-related events were recorded.

RESULTS

All 12 patients who received more than 6 months of peginterferon in the original study were included in this analysis. The cohort was mostly white (83%) and male (92%) and ranged in age from 18 to 58 years (mean = 42.6). Most patients had advanced but compensated liver disease at baseline, a median HBV DNA level of 536 IU per mL and median HDV RNA level of 6.86 log10 genome equivalents per mL. The treatment duration averaged 6.1 years (range 0.8-14.3) with a total follow-up of 8.8 years (range 1.7-17.6). At last follow-up, seven (58%) patients had durable undetectable HDV RNA in serum, and four (33%) cleared HBsAg. Overall, one of seven (14%) responders died or had a liver-related event vs four of five (80%) non-responders.

CONCLUSIONS

With further follow-up, an extended course of peginterferon therapy was found to result in sustained clearance of HDV RNA and favourable clinical outcomes in more than half of patients and loss of HBsAg in a third.

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.

Blocking Entry of Hepatitis B and D Viruses to Hepatocytes as a Novel Immunotherapy for Treating Chronic Infections

Background

Chronic hepatitis B and D virus (HBV/HDV) infections can cause cancer. Current HBV therapy using nucleoside analogues (NAs) is life-long and reduces but does not eliminate the risk of cancer. A hallmark of chronic hepatitis B is a dysfunctional HBV-specific T-cell response. We therefore designed an immunotherapy driven by naive healthy T cells specific for the HDV antigen (HDAg) to bypass the need for HBV-specific T cells in order to prime PreS1-specific T cells and PreS1 antibodies blocking HBV entry.

Methods

Ten combinations of PreS1 and/or HDAg sequences were evaluated for induction of PreS1 antibodies and HBV- and HDV-specific T cells in vitro and in vivo. Neutralization of HBV by PreS1-specific murine and rabbit antibodies was evaluated in cell culture, and rabbit anti-PreS1 were tested for neutralization of HBV in mice repopulated with human hepatocytes.

Results

The best vaccine candidate induced T cells to PreS1 and HDAg, and PreS1 antibodies blocking HBV entry in vitro. Importantly, adoptive transfer of PreS1 antibodies prevented, or modulated, HBV infection after a subsequent challenge in humanized mice.

Conclusions

We here describe a novel immunotherapy for chronic HBV/HDV that targets viral entry to complement NAs and coming therapies inhibiting viral maturation.

The changing context of hepatitis D

The global epidemiology of hepatitis D is changing with the widespread implementation of vaccination against hepatitis B. In high-income countries that achieved optimal control of HBV, the epidemiology of hepatitis D is dual, consisting of an ageing cohort of domestic patients with advanced liver fibrosis who represent the end stage of the natural history of HDV, and of a younger generation of immigrants from endemic countries who account for the majority of new infections. As observed in Europe in the 1980s, the distinctive clinical characteristic of chronic hepatitis D in endemic countries is the accelerated progression to cirrhosis and hepatocellular carcinoma. Despite some recent progress, the therapeutic management of HDV remains unsatisfactory, as most patients are not cured of HDV with currently available medicines. This review article describes the current epidemiology and clinical features of chronic hepatitis D, based on the literature published in the last 10 years.

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.

Human hepatitis D virus-specific T cell epitopes

HDV is a small, defective RNA virus that requires the HBsAg of HBV for its assembly, release, and transmission. Chronic HBV/HDV infection often has a severe clinical outcome and is difficult to treat. The important role of a robust virus-specific T cell response for natural viral control has been established for many other chronic viral infections, but the exact role of the T cell response in the control and progression of chronic HDV infection is far less clear. Several recent studies have characterised HDV-specific CD4+ and CD8+ T cell responses on a peptide level. This review comprehensively summarises all HDV-specific T cell epitopes described to date and describes our current knowledge of the role of T cells in HDV infection. While we now have better tools to study the adaptive anti-HDV-specific T cell response, further efforts are needed to define the HLA restriction of additional HDV-specific T cell epitopes, establish additional HDV-specific MHC tetramers, understand the degree of cross HDV genotype reactivity of individual epitopes and understand the correlation of the HBV- and HDV-specific T cell response, as well as the breadth and specificity of the intrahepatic HDV-specific T cell response.

New insights into HDV persistence: The role of interferon response and implications for upcoming novel therapies

Chronic hepatitis D (CHD), a global health problem, manifests as the most severe form of viral hepatitis. The causative agent, HDV, is the smallest known human virus; it replicates its circular single-stranded RNA genome in the nucleus of hepatocytes. HDV requires HBV-encoded envelope proteins for dissemination and de novo cell entry. However, HDV can also spread through cell division. Following entry into hepatocytes, replicative intermediates of HDV RNA are sensed by the pattern recognition receptor MDA5 (melanoma differentiation antigen 5) resulting in interferon (IFN)-β/λ induction. This IFN response strongly suppresses cell division-mediated spread of HDV genomes, however, it only marginally affects HDV RNA replication in already infected, resting hepatocytes. Monotherapy with IFN-α/λ shows efficacy but rarely results in HDV clearance. Recent molecular insights into key determinants of HDV persistence and the accelerated development of specifically acting antivirals that interfere with the replication cycle have revealed promising new therapeutic perspectives. In this review, we briefly summarise our knowledge on replication/persistence of HDV, the newly discovered HDV-like agents, and the interplay of HDV with the IFN response and its consequences for persistence. Finally, we discuss the possible role of IFNs in combination with upcoming therapies aimed at HDV cure.

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.

A transient early HBV-DNA increase during PEG-IFNα therapy of hepatitis D indicates loss of infected cells and is associated with HDV-RNA and HBsAg reduction

HBV-DNA levels are low or even undetectable in the majority HDV-infected patients. The impact of PEG-IFNα on HBV-DNA kinetics in HDV-infected patients has not been studied in detail. We analysed data of a prospective treatment trial where 120 HDV-RNA-positive patients were randomized to receive PEG-IFNα-2a plus tenofovir-disoproxil-fumarate (PEG-IFNα/TDF, n = 59) or placebo (PEG-IFNα/PBO; n = 61) for 96 weeks. At week 96, HBV-DNA was still quantifiable in 71% of PEG-IFNα/PBO-treated patients but also in 76% of PEG-IFNα/TDF-treated patients, despite low HBV-DNA baseline values. Surprisingly, a transient HBV-DNA increase between weeks 12 and 36 was observed in 12 in PEG-IFNα/TDF-treated and 12 PEG-IFNα/PBO-treated patients. This increase was positively associated with HBsAg loss [(P = 0.049, odds ratio (OR) 5.1] and HDV-RNA suppression (P = 0.007, OR 4.1) at week 96. Biochemical markers of cell death (M30 and ALT) were higher during the HBV-DNA peak but no distinct systemic immune pattern could be observed by screening 91 soluble inflammatory markers. In conclusion, an early increase in HBV-DNA during PEG-IFNα-2a therapy occurred in more than 20% of patients, even in TDF-treated patients. This transient HBV-DNA rise may indicate PEG-IFNα-induced cell death and lead to long-term HDV-RNA suppression and HBsAg loss.

Persistent Control of Hepatitis B Virus and Hepatitis Delta Virus Infection Following REP 2139-Ca and Pegylated Interferon Therapy in Chronic Hepatitis B Virus/Hepatitis Delta Virus Coinfection

The nucleic acid polymer REP 2139 inhibits assembly/secretion of hepatitis B virus (HBV) subviral particles. Previously, REP 2139-Ca and pegylated interferon (pegIFN) in HBV/hepatitis delta virus (HDV) coinfection achieved high rates of HDV RNA and hepatitis B surface antigen (HBsAg) loss/seroconversion in the REP 301 study (NCT02233075). The REP 301-LTF study (NCT02876419) examined safety and efficacy during 3.5 years of follow-up. In the current study, participants completing therapy in the REP 301 study were followed for 3.5 years. Primary outcomes were safety and tolerability, and secondary outcomes were HDV functional cure (HDV RNA target not detected [TND], normal alanine aminotransferase [ALT]), HBV virologic control (HBV DNA ≤2,000 IU/mL, normal ALT), HBV functional cure (HBV DNA TND; HBsAg <0.05 IU/mL, normal ALT), and HBsAg seroconversion. Supplemental analysis included high-sensitivity HBsAg (Abbott ARCHITECT HBsAg NEXT), HBV pregenomic RNA (pgRNA), HBsAg/hepatitis B surface antibody (anti-HBs) immune complexes (HBsAg ICs), and hepatitis B core-related antigen (HBcrAg). Asymptomatic grade 1-2 ALT elevations occurred in 2 participants accompanying viral rebound; no other safety or tolerability issues were observed. During therapy and follow-up, HBsAg reductions to <0.05 IU/mL were also <0.005 IU/mL. HBsAg ICs declined in 7 of 11 participants during REP 2139-Ca monotherapy and in 10 of 11 participants during follow-up. HDV functional cure persisted in 7 of 11 participants; HBV virologic control persisted in 3 and functional cure (with HBsAg seroconversion) persisted in 4 of these participants. Functional cure of HBV was accompanied by HBV pgRNA TND and HBcrAg <lower limit of quantitation. Conclusion: REP 2139-Ca + pegIFN is not associated with long-term safety or tolerability issues. The establishment of HDV functional cure and HBV virologic control/functional cure and HBsAg seroconversion are durable over 3.5 years and may reflect removal of integrated HBV DNA from the liver. Further investigation is warranted in larger studies.

Effectiveness of pegylated interferon monotherapy in the treatment of chronic hepatitis D virus infection: A meta-analysis

Chronic HDV infection often is associated with aggressive form of liver disease, compared to chronic HBV mono-infection. However, chronic HDV treatment is challenging because currently there is no approved regimen for affected patients. While standard interferon with/without nucleos(t)ide analogues were reported to be inferior to pegylated interferon (peginterferon) as HDV treatment according to few randomized clinical trials. This meta-analysis will summarize the results of studies on the effectiveness of peginterferon as HDV treatment regimen. An electronic search was performed using PubMed, Cochrane Library, Research Gate, and Medline databases. Studies involving patients who received peginterferon therapy for at least 48 weeks and followed up for 24 weeks post-therapy were included. All analyses were conducted using Review Manager 5.3 designed for Cochrane Reviews. The primary efficacy endpoint was virological response (VR) or HDV-RNA negativity at the end of the follow-up period, whereas secondary efficacy endpoints were biochemical response (BR) or ALT normalization and HBsAg clearance with seroconversion to anti-HBs at the end of follow-up period. Data were abstracted from 13 relevant studies with a total of 475 patients who were treated with peginterferon alpha-2a or -2b. At the end of 24-week post-treatment the pooled VR was achieved in 29% of patients with 95% CI [24%; 34%], BR was reached in 33% of patients [95% CI 27%; 40%] and HBsAg clearance with seroconversion to anti-HBs was achieved in 1% of patients with 95% CI [-0.02; 0.05]. In conclusion, this study showed that peginterferon has limited effectiveness in HDV treatment, since only one-third of chronic HDV patients achieved viral clearance and normalized ALT levels. Morever, HBsAg clearance with seroconversion to anti-HBs has been rarely observed among chronic HDV patients.

Ten-year follow-up of a randomized controlled clinical trial in chronic hepatitis delta

Hepatitis delta virus (HDV) infection causes the most severe form of viral hepatitis. PEG-interferon alpha-2a (PEG-IFNα-2a) is the only effective treatment but its long-term clinical impact is unclear. The aim of this study was to investigate the long-term outcome after 48 weeks of pegylated interferon alpha-2a therapy. We performed a retrospective follow-up study of the Hep-Net-International-Delta-Hepatitis-Intervention-Study 1 (HIDIT-I trial). Patients had received 48 weeks of treatment with either PEG-IFNα-2a plus adefovir dipivoxil (ADV) (Group I), PEG-IFNα-2a alone (Group II) or adefovir dipivoxil alone (Group III). Liver-related complications were defined as liver-related death, liver transplantation, liver cancer and hepatic decompensation defined as development of Child-Pugh scores B or C or an increase in Model for End-stage Liver Disease (MELD) scores of five or more points in relation to baseline values. Patients were considered for further analysis when they were retreated with PEG-IFNα-2a. Follow-up data (at least 1 visit beyond post-treatment week 24) were available for 60 patients [Group I, (n = 19), Group II (n = 20), Group III (n = 21)]. Mean time of follow-up was 8.9 (1.6 - 13.4) years. 19 patients were retreated with IFN-based therapy: 42% (n = 8) in PEG-IFNα-2a arms and 58% (n = 11) in the adefovir only arm. Clinical complications on long-term follow-up occurred in 17 patients and were associated with nonresponse to therapy and baseline cirrhosis. The annual event-free survival rate in patients with cirrhosis vs noncirrhotic patients at year 5 and 10 was 70% vs 91% and 35% vs 76%. Long-term follow-up of a large randomized clinical trial suggests that off-treatment HDV RNA response to PEG-IFNα-2a treatment leads to improved clinical long-term outcome.

Long-Term Study of Hepatitis Delta Virus Infection at Secondary Care Centers: The Impact of Viremia on Liver-Related Outcomes

BACKGROUND AND AIMS

Hepatitis delta virus (HDV) infection is associated with fast progression to liver cirrhosis and liver complications. Previous studies have, however, been mainly from tertiary care centers, with risk for referral bias toward patients with worse outcomes. Furthermore, the impact of HDV viremia per se on liver-related outcomes is not really known outside the human immunodeficiency virus co-infection setting. We have therefore evaluated the long-term impact of HDV viremia on liver-related outcomes in a nationwide cohort of patients with hepatitis B and D co-infection, cared for at secondary care centers in Sweden.

APPROACH AND RESULTS

In total, 337 patients with anti-HDV positivity, including 233 patients with HDV RNA viremia and 91 without HDV viremia at baseline, were retrospectively studied, with a mean follow-up of 6.5 years (range, 0.5-33.1). The long-term risks for liver-related events (i.e., hepatocellular carcinoma [HCC], hepatic decompensation, or liver-related death/transplantation) were assessed, using Cox regression analysis. The risk for liver-related events and HCC was 3.8-fold and 2.6-fold higher, respectively, in patients with HDV viremia compared with those without viremia, although the latter was not statistically significant. Among patients with HDV viremia with no baseline cirrhosis, the cumulative risk of being free of liver cirrhosis or liver-related events was 81.9% and 64.0% after 5 and 10 years of follow-up, respectively. This corresponds to an incidence rate of 0.04 cases per person-year.

CONCLUSIONS

HDV RNA viremia is associated with a 3.8-fold higher risk for liver-related outcomes. The prognosis was rather poor for patients with HDV viremia without cirrhosis at baseline, but it was nevertheless more benign than previous estimates from tertiary centers. Our findings may be of importance when making decisions about treatment and evaluating potential outcomes of upcoming antivirals against HDV.