Form Of Chronic Viral Hepatitis Research Articles

Characterizing Hepatitis Delta in Spain and the gaps in its management

Background and aimsChronic hepatitis D (CHD) is a severe form of chronic viral hepatitis. The estimated hepatitis delta prevalence in Spain is around 5% of patients with hepatitis B. Reimbursement of new antiviral therapies (Bulevirtide, BLV) was delayed in our country until February 2024. We aimed to characterize the clinical profile of patients with HDV/HBV infection in Spain and current barriers in their management at the time of BLV approval. MethodMulticenter registry including patients with positive anti-HDV serology actively monitored in 30 Spanish centers. Epidemiological, clinical and virological variables were recorded at the start of follow-up and at the last visit. ResultsWe identified 329 anti-HDV patients, 41% were female with median age 51 years. The most common geographical origin was Spain (53%) and East Europe (24%). Patients from Spain were older and had HCV and HIV coinfection probably associated to past drug injection (p<0.01). HDV-RNA was positive in 138 of 221 assessed (62%). Liver cirrhosis was present at diagnosis in 33% and it was more frequent among viremic patients (58% vs 25%, p<0.01). After a median follow-up of 6 (3–12) years, 44 (16%) resolved infection (18 spontaneously and 26 after Peg-INF). An additional 10% of patients developed cirrhosis (n=137) during follow-up (45% had portal hypertension and 14% liver decompensation). Liver disease progression was associated to persisting viremia. ConclusionOne-third of the patients with CHD already have cirrhosis at diagnosis. Persistence of positive viremia is associated to rapid liver disease progression. Importantly, barriers to locally determine/quantify HDV-RNA were present.

Deciphering the Role of Post-Translational Modifications and Cellular Location of Hepatitis Delta Virus (HDV) Antigens in HDV-Mediated Liver Damage in Mice.

Hepatitis D virus (HDV) infection represents the most severe form of chronic viral hepatitis. We have shown that the delivery of HDV replication-competent genomes to the hepatocytes using adeno-associated virus (AAV-HDV) as gene delivery vehicles offers a unique platform to investigate the molecular aspects of HDV and associated liver damage. For the purpose of this study, we generated HDV genomes modified by site-directed mutagenesis aimed to (i) prevent some post-translational modifications of HDV antigens (HDAgs) such as large-HDAg (L-HDAg) isoprenylation or short-HDAg (S-HDAg) phosphorylation; (ii) alter the localization of HDAgs within the subcellular compartments; and (iii) inhibit the right conformation of the delta ribozyme. First, the different HDV mutants were tested in vitro using plasmid-transfected Huh-7 cells and then in vivo in C57BL/6 mice using AAV vectors. We found that Ser177 phosphorylation and ribozymal activity are essential for HDV replication and HDAg expression. Mutations of the isoprenylation domain prevented the formation of infectious particles and increased cellular toxicity and liver damage. Furthermore, altering HDAg intracellular localization notably decreased viral replication, though liver damage remained unchanged versus normal HDAg distribution. In addition, a mutation in the nuclear export signal impaired the formation of infectious viral particles. These findings contribute valuable insights into the intricate mechanisms of HDV biology and have implications for therapeutic considerations.

Results of HDV RNA detection in male seminal fluid and female cervical swab samples using RT-PCR

Mongolia has an extremely high prevalence of hepatitis D virus (HDV), which leads to increased morbidity and mortality from hepatocellular carcinoma (HCC). HDV is the most severe form of chronic viral hepatitis (CVH). A recent study estimated that the prevalence of anti-HDV was 67.5% among hepatitis B surface antigen-positive cases in Mongolia. HDV infection is particularly prevalent in sexually active young people. The virus may be transmitted through sexual intercourse, and it is crucial to confirm this by detecting HDV RNA in semen and cervical swabs of patients with chronic hepatitis delta. This pilot study was conducted with 16 participants, including eight males and eight females. Viral RNA was isolated from the blood, male seminal fluid, and female cervical swab samples of all participants in the study. HDV RNA was quantified using RT-PCR in samples from blood, seminal fluid, and cervical swabs. This study found that the detection rate of HDV RNA differed between male and female samples, with 62.5% of seminal fluid samples in the male cohort being positive compared with 87.5% in the female cohort. The data shows a statistically significant difference between genders for the presence of HDVRNA in seminal fluid and cervical swabs (OR 0.238, 95% CI= 0.02-3.01). A significant correlation was found between blood HDV RNA quantity and HDV RNA presence status in seminal fluid and cervical swab samples, indicating a potential risk of sexual HDV transmission. The R2 values for semen and cervical swab samples were 0.1095 and 0.9755, respectively.

JAK1 promotes HDV replication and is a potential target for antiviral therapy

Chronic co-infection with HBV and HDV leads to the most aggressive form of chronic viral hepatitis. To date, no treatment induces efficient viral clearance, and a better characterization of virus-host interactions is required to develop new therapeutic strategies. Using loss-of-function strategies, we validated the unexpected proviral activity of Janus kinase 1 (JAK1) - a key player in innate immunity - in the HDV life cycle and determined its mechanism of action on HDV through various functional analyses including co-immunoprecipitation assays. We confirmed the key role of JAK1 kinase activity in HDV infection. Moreover, our results suggest that JAK1 inhibition is associated with a modulation of ERK1/2 activation and S-HDAg phosphorylation, which is crucial for viral replication. Finally, we showed that FDA-approved JAK1-specific inhibitors are efficient antivirals in relevant invitro models including primary human hepatocytes. Taken together, we uncovered JAK1 as a key host factor for HDV replication and a potential target for new antiviral treatment. Chronic hepatitis D is the most aggressive form of chronic viral hepatitis. As no curative treatment is currently available, new therapeutic strategies based on host-targeting agents are urgently needed. Here, using loss-of-function strategies, we uncover an unexpected interaction between JAK1, a major player in the innate antiviral response, and HDV infection. We demonstrated that JAK1 kinase activity is crucial for both the phosphorylation of the delta antigen and the replication of the virus. By demonstrating the antiviral potential of several FDA-approved JAK1 inhibitors, our results could pave the way for the development of innovative therapeutic strategies to tackle this global health threat.

Hepatitis D Virus and HBsAg Dynamics in the era of new Antiviral Treatments.

Hepatitis D virus (HDV) infection is the most severe form of chronic viral hepatitis, with no FDA-approved therapy. Progress in the development of effective HDV treatments is accelerating. This review highlights how mathematical modeling is improving understanding of HDV-HBsAg-host dynamics during antiviral therapy and generating insights into the efficacy and modes of action (MOA) of new antiviral agents. Clinical trials with pegylated-interferon-λ, bulevertide,nucleic acid polymers, and/or lonafarnibagainst various steps of theHDV-life cycle have revealed new viral-kinetic patterns that were not observed under standard treatment with pegylated-interferon-α. Modeling indicated that the half-lives of circulating HDV and HBsAg are ~ 1.7 d and ~ 1.3 d, respectively, estimated the relative response of HDV and HBsAg during different antiviral therapies, and provided insights into the efficacy and MOA of drugs in development for treating HDV, which can inform response-guided therapy to individualize treatment duration. Mathematical modeling of HDV and HBsAg kinetics provides a window into the HDV virus lifecycle, HDV-HBsAg-host dynamics during antiviral therapy, and the MOA of new drugs for HDV.

Clinical long-term outcome of hepatitis D compared to hepatitis B monoinfection

Background and aimsHepatitis D virus (HDV) infection causes the most severe form of chronic viral hepatitis. However, it is still unclear to what extent the underlying cirrhosis may contribute to disease progression. The aim of this study was to compare the long-term outcome of HDV infection with HBV monoinfection in a single-center cohort of both non-cirrhotic and cirrhotic patients.MethodWe retrospectively studied 175 patients with chronic hepatitis D (CHD) who were followed for at least 6 months (median of 6.3 (0.6–23.6) years). In addition, we selected 175 patients with HBV monoinfection (CHB) who were matched for gender, age, region of origin, HBeAg status, and bilirubin. Liver-related clinical end points were defined as hepatic decompensation (ascites, encephalopathy, variceal bleeding), liver transplantation, HCC, or liver-related death.ResultsClinical complications developed earlier (4.6 vs. 6.2 years) and more frequently (35.4% vs. 12.6%, p < 0.01) in CHD patients. In a multivariate Cox regression, HDV infection was independently associated with the development of end points (p < 0.01; HR: 3.0; 95% CI 1.4–6.4). However, in cirrhotic patients there were no significant differences between HBV and HDV in the development of end points. Besides, CHB patients with cirrhosis developed more frequently HCC (35.5%) than CHD patients with cirrhosis (18.5%).ConclusionOur results confirmed that HDV leads to a faster progression to cirrhosis compared to HBV. However, once cirrhosis is present, not HDV but the underlying cirrhosis is the dominate intrinsic risk factor for the development of liver-related end points and for the progression to HCC.

A-304 A RT-PCR Assay for Detection and Quantification of Hepatitis D Virus (HDV)

Abstract Background Hepatitis D virus (HDV), also called Delta Hepatitis, is associated with the presence of the Hepatitis B virus (HBV) and is responsible for the infection and inflammation of liver cells. It is estimated that 15–20 million people worldwide are affected by HDV. In Brazil, Hepatitis D has high prevalence rates in the Amazon Basin. HDV is an enveloped virus with a 36 nm average diameter. The HDV virion involves a negative-sense, single-stranded circular RNA molecule associated with an inner-core delta antigen surrounded by envelope glycoproteins. HDV-infected individuals may not show signs or symptoms of the disease. When present, the most common are: tiredness, dizziness, nausea and/or vomiting, fever, abdominal pain, and yellow skin/eyes. Chronic Hepatitis D is considered the most severe form of chronic viral hepatitis, with more rapid progression to cirrhosis and an increased risk for decompensation, hepatocellular carcinoma (HCC), and death. Molecularly, determining the concentration of virus circulating in the blood of HDV patients is extremely important for diagnosis. The Quantitative Polymerase Chain Reaction (qPCR) is a molecular technique capable of detecting the viral genome with high sensitivity and specificity, ensuring the safety of the result. Therefore, this study aims to describe the analytical validation of a one-step RT-qPCR assay for HDV detection. Methods Assay performance was evaluated using commercial quantified positive control to HDV (1000, 100, 10, 1, and 0.5 IU/µL), and the parameters of analysis included: standardization assays, efficiency, and detection limit. For specificity evaluation, positive samples for Epstein-Barr Virus (EBV), Herpes Simplex Virus (HSV), Cytomegalovirus (CMV), Hepatitis B Virus (HBV), and Hepatitis C Virus (HCV) were used. RNA isolation was performed with the MagNA Pure 24 Total NA Isolation Kit at the automated platform MagNA Pure 24 System (Roche Diagnostics, Basel, Switzerland), according to the manufacturer's instructions. Altona RealStar HDV RT-PCR Kit 1.0 (Altona Diagnostics, Hamburg, Germany) was used to directly amplify RNA samples on the qPCR instrument, according to the manufacturer's instructions. Results The standardization assays indicated good qPCR amplification curves and high fluorescence levels between the controls evaluated. The assay demonstrated an average efficiency of 95%, with a coefficient of determination (r2) of 0.99. The detection limit of the test was 1 IU/µL for the HDV target (95% confidence interval). No cross-reactions with closely related viruses were observed (15 HDV-negative human plasma samples), indicating 100% specificity. The experiments performed to evaluate the precision demonstrated optimal repeatability and reproducibility. Conclusion The HDV diagnostic is required to ensure sensitive, specific and accurate identification of the viral agent and thus prompt surveillance actions such as epidemiological monitoring and control measures of infection. The RT-qPCR assay described here provides a reliable, highly specific, and sensitive method for the detection and quantification of HDV. Nevertheless, the assay needs to be evaluated in conjunction with a clinical and epidemiological context.

HDV RNA assays: Performance characteristics, clinical utility, and challenges.

Coinfection with HBV and HDV results in hepatitis D, the most severe form of chronic viral hepatitis, frequently leading to liver decompensation and HCC. Pegylated interferon alpha, the only treatment option for chronic hepatitis D for many years, has limited efficacy. New treatments are in advanced clinical development, with one recent approval. Diagnosis and antiviral treatment response monitoring are based on detection and quantification of HDV RNA. However, the development of reliable HDV RNA assays is challenged by viral heterogeneity (at least 8 different genotypes and several subgenotypes), intrahost viral diversity, rapid viral evolution, and distinct secondary structure features of HDV RNA. Different RNA extraction methodologies, primer/probe design for nucleic acid tests, lack of automation, and overall dearth of standardization across testing laboratories contribute to substantial variability in performance characteristics of research-based and commercial HDV RNA assays. A World Health Organization (WHO) standard for HDV RNA, available for about 10 years, has been used by many laboratories to determine the limit of detection of their assays and facilitates comparisons of RNA levels across study centers. Here we review challenges for robust pan genotype HDV RNA quantification, discuss particular clinical needs and the importance of reliable HDV RNA quantification in the context of drug development and patient monitoring. We summarize distinct technical features and performance characteristics of available HDV RNA assays. Finally, we provide considerations for the use of HDV RNA assays in the context of drug development and patient monitoring.

Bulevirtide-based treatment strategies for chronic hepatitis delta: A review.

Chronic hepatitis Delta (CHD) is a rare and severe form of chronic viral hepatitis. Until recently, the only therapeutic approach has been the off-label use of a 48 weeks course of PegInterferon alpha (PegIFNα), that was characterized by suboptimal efficacy and burdened by significant side effects that limited treatment applicability in patients with advanced liver disease. In July 2020, European Medicines Agency (EMA) conditionally approved the entry inhibitor Bulevirtde (BLV) at the dose of 2mg/day for the treatment of adult patients with compensated CHD. Efficacy and safety of BLV in CHD have been evaluated in clinical trials either as monotherapy or in combination with PegIFNα. These results were confirmed by real-life studies, which also evaluated long-term BLV monotherapy in patients with advanced compensated cirrhosis. Notwithstanding these promising results there are still several issues to be addressed, such as the optimal duration of the treatment, the rates of off-therapy responses, as well as the long-term clinical benefits. This review summarizes updated and current literature data about clinical trials and real-life studies with BLV monotherapy and/or in combination with PegIFNα.

Diagnosis of HDV: From virology to non-invasive markers of fibrosis.

Hepatitis D viral infection in humans is a disease that requires the establishment of hepatitis B, relying on hepatitis B surface Ag and host cellular machinery to replicate and propagate the infection. Since its discovery in 1977, substantial progress has been made to better understand the hepatitis D viral life cycle, pathogenesis and modes of transmission along with expanding on clinical knowledge related to prevention, diagnosis, monitoring and treatment. The availability of serologic diagnostic assays for hepatitis D infection has evolved over time with current widespread availability, improved detection and standardized reporting. With human migration, the epidemiology of hepatitis D infection has changed over time. Thus, the ability to use diagnostic assays remains essential to monitor the global impact of hepatitis D infection. Separately, while liver biopsy remains the gold standard for the staging of this rapidly progressive and severe form of chronic viral hepatitis, there is an unmet need for clinical monitoring of chronic hepatitis D infection for management of progressive disease. Thus, exploration of the utility of non-invasive fibrosis markers in hepatitis D is ongoing. In this review, we discuss the virology, the evolution of diagnostics and the development of non-invasive markers for the detection and monitoring of fibrosis in patients with hepatitis D infection.

Hepatitis D virus interferes with hepatitis B virus RNA production via interferon-dependent and -independent mechanisms

Chronic coinfection with HBV and HDV leads to the most aggressive form of chronic viral hepatitis. Herein, we aimed to elucidate the molecular mechanisms underlying the widely reported observation that HDV interferes with HBV in most coinfected patients. Patient liver tissues, primary human hepatocytes, HepaRG cells and human liver chimeric mice were used to analyze the effect of HDV on HBV using virological and RNA-sequencing analyses, as well as RNA synthesis, stability and association assays. Transcriptomic analyses in cell culture and mouse models of coinfection enabled us to define an HDV-induced signature, mainly composed of interferon (IFN)-stimulated genes (ISGs). We also provide evidence that ISGs are upregulated in chronically HDV/HBV-coinfected patients but not in cells that only express HDV antigen (HDAg). Inhibition of the hepatocyte IFN response partially rescued the levels of HBV parameters. We observed less HBV RNA synthesis upon HDV infection or HDV protein expression. Additionally, HDV infection or expression of HDAg alone specifically accelerated the decay of HBV RNA, and HDAg was associated with HBV RNAs. On the contrary, HDAg expression did not affect other viruses such as HCV or SARS-CoV-2. Our data indicate that HDV interferes with HBV through both IFN-dependent and IFN-independent mechanisms. Specifically, we uncover a new viral interference mechanism in which proteins of a satellite virus affect the RNA production of its helper virus. Exploiting these findings could pave the way to the development of new therapeutic strategies against HBV. Although the molecular mechanisms remained unexplored, it has long been known that despite its dependency, HDV decreases HBV viremia in patients. Herein, using invitro and invivo models, we showed that HDV interferes with HBV through both IFN-dependent and IFN-independent mechanisms affecting HBV RNA metabolism, and we defined the HDV-induced modulation signature. The mechanisms we uncovered could pave the way for the development of new therapeutic strategies against HBV by mimicking and/or increasing the effect of HDAg on HBV RNA. Additionally, the HDV-induced modulation signature could potentially be correlated with responsiveness to IFN-α treatment, thereby helping to guide management of HBV/HDV-coinfected patients.

Recent Advances in Protective Vaccines against Hepatitis Viruses: A Narrative Review.

Vaccination has been confirmed to be the safest and, sometimes, the only tool of defense against threats from infectious diseases. The successful history of vaccination is evident in the control of serious viral infections, such as smallpox and polio. Viruses that infect human livers are known as hepatitis viruses and are classified into five major types from A to E, alphabetically. Although infection with hepatitis A virus (HAV) is known to be self-resolving after rest and symptomatic treatment, there were 7134 deaths from HAV worldwide in 2016. In 2019, hepatitis B virus (HBV) and hepatitis C virus (HCV) resulted in an estimated 820,000 and 290,000 deaths, respectively. Hepatitis delta virus (HDV) is a satellite virus that depends on HBV for producing its infectious particles in order to spread. The combination of HDV and HBV infection is considered the most severe form of chronic viral hepatitis. Hepatitis E virus (HEV) is another orally transmitted virus, common in low- and middle-income countries. In 2015, it caused 44,000 deaths worldwide. Safe and effective vaccines are already available to prevent hepatitis A and B. Here, we review the recent advances in protective vaccines against the five major hepatitis viruses.

Identification of selective hepatitis delta virus ribozyme inhibitors by high-throughput screening of small molecule libraries

Chronic hepatitis delta is the most severe form of chronic viral hepatitis and is associated with faster progression towards cirrhosis, liver decompensation, and hepatocellular carcinoma. Hepatitis delta virus (HDV)'s tight dependency on hepatitis B virus and the host cell machinery for its life cycle limits the development of direct-acting antivirals. Thus, we aimed to identify compounds that could block HDV replication by targeting its antigenomic ribozyme. We generated stable Huh7 human hepatoma cells expressing a reporter gene (Gaussia luciferase) either downstream (Gluc-2xRz) or upstream (2xRz-Gluc) of two HDV antigenomic ribozyme sequences. We performed high-throughput screening of three small molecule libraries. The secreted luciferase was measured as a readout of ribozyme inhibition upon addition of the molecules. Each plate was considered valid when the Z factor was >0.4. Specificity and toxicity evaluations were performed for the hits with a Z-score >5 and half-maximal inhibitory concentration was calculated by performing a dose-response experiment. A dose-dependent induction of luciferase expression was detected in Gluc-2xRz-transfected cells incubated with the antisense morpholino, suggesting that the catalytic activity of the ribozyme cloned downstream of the reporter gene was efficiently inhibited. Among the 6,644 compounds screened, we identified four compounds that showed a specific inhibitory effect on the HDV antigenomic ribozyme in Gluc-2xRz cells, i.e. three histone deacetylase inhibitors and the purine analogue 8-azaguanine. The latter also significantly decreased HDV replication (by 40%) in differentiated HepaRG cells six days post infection. Using a novel cell culture model, we identified four small molecules active against the antigenomic HDV ribozyme. These results may provide insights into the structural requirements of molecules designed for the potent and specific inhibition of HDV replication. Chronic hepatitis delta is the most severe form of chronic viral hepatitis and is associated with faster progression towards cirrhosis, liver decompensation, and the development of hepatocellular carcinoma. Despite the current development of several new compounds, there is still a need for efficient antiviral treatments specifically targeting hepatitis delta virus (HDV). This work describes a novel cell culture model that allows for the high-throughput screening of compounds able to inhibit HDV ribozymes. We identified four small molecules active against the antigenomic HDV ribozyme (the ribozyme involved in the early step of HDV replication), with the strongest activity shown by 8-azaguanine, a purine analogue. Our data may provide insights into the structural requirements of molecules designed to inhibit HDV.

A stable hepatitis D virus-producing cell line for host target and drug discovery

Chronic hepatitis D is the most aggressive form of chronic viral hepatitis. It is caused by super-infection of hepatitis B virus (HBV)-infected hepatocytes with hepatitis D virus (HDV). While the recent conditional approval of bulevirtide for HDV treatment offers a new therapeutic modality in Europe, there is an unmet medical need to further improve therapy. A more detailed characterization of virus-host interactions is needed for the identification of novel therapeutic targets. Addressing this need, we engineered a new stably-transformed cell line, named HuH7-2C8D, producing high titer recombinant HDV and allowing the study of viral particles morphogenesis and infectivity. Using this culture system, where viral propagation by re-infection is limited, we observed an increased accumulation of edited version of the viral genomes within secreted HDV viral particles over time that is accompanied with a decrease in viral particle infectivity. We confirmed the interaction of HDV proteins with a previously described host factor in HuH7-2C8D cells and additionally showed that these cells are suitable for co-culture assays with other cell types such as macrophages. Finally, the use of HuH7-2C8D cells allowed to confirm the dual antiviral activity of farnesyl transferase inhibitors, including the clinical candidate lonafarnib, against HDV. In conclusion, we have established an easy-to-handle cell culture model to investigate HDV replication, morphogenesis, and host interactions. HuH7-2C8D cells are also suitable for high-throughput antiviral screening assays for the development of new therapeutic strategies.

Immunology of hepatitis D virus infection: General concepts and present evidence.

Infection with the hepatitis D virus induces the most severe form of chronic viral hepatitis, affecting over 12 million people worldwide. Chronic HDV infection leads to rapid development of liver cirrhosis and hepatocellular carcinoma in ~70% of patients within 15 years of infection. Recent evidence suggests that an interplay of different components of the immune system are contributing to viral control and may even be implicated in liver disease pathogenesis. This review will describe general concepts of antiviral immune response and elicit the present evidence concerning the interplay of the hepatitis D virus with the immune system.

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.

Bulevirtide for patients with compensated chronic hepatitis delta: A review.

Chronic hepatitis delta (CHD) affects approximately 10-20million people worldwide and represents the most severe form of chronic viral hepatitis, as it is characterized by high rates of progression to cirrhosis and its complications (end-stage liver disease, hepatocellular carcinoma). In the last 30 years, the only treatment option for CHD has been represented by the off-label administration of Interferon (or Pegylated Interferon)-alpha: antiviral treatment, however, resulted in suboptimal (20-30%) virological response and was burdened by several side effects, de facto contraindicating Interferon (IFN) administration in patients with more advanced liver disease. Recently, Bulevirtide (BLV), a first-in-class HBV-HDV entry inhibitor blocking Na+ -taurocholate co-transporting polypeptide (NTCP), has provided very promising efficacy data in Phase II and Phase III (interim analysis) trials as well as in preliminary real-life reports. In July 2020, BLV has granted conditional approval by EMA for treatment of compensated CHD, at the dose of 2mg/day by self-administered subcutaneous injections. In Phase II and Phase III trials, BLV was evaluated at different doses (2 vs. 10 mg/day) for 24 or 48 weeks, either in monotherapy or in combination with PegIFN. Administration of BLV monotherapy for 24 or 48 weeks resulted in 50%-83% virological response (HDV RNA ≥ 2 Log decline) rates and 45%-78% ALT normalization. Combination therapy with PegIFN provided synergistic effects. These results were replicated in real-life studies and confirmed also in patients with advanced cirrhosis and clinically significant portal hypertension. BLV treatment was optimally tolerated, resulting only in an asymptomatic increase of bile acids.

Loss of hepatitis D virus infectivity upon farnesyl transferase inhibitor treatment associates with increasing RNA editing rates revealed by a new RT-ddPCR method

Chronic hepatitis D is the most severe form of chronic viral hepatitis and to date, efficient therapeutic approaches against hepatitis D virus (HDV) are limited. Among the antiviral molecules currently tested in clinical trials, the farnesyl transferase inhibitor (FTI) Lonafarnib inhibits the prenylation of the large delta antigen (L-HDAg), blocking virus assembly. Given the importance of L-HDAg in the virus life cycle, we hypothesized that Lonafarnib treatment may have side effects on virus replication. Here, we setup an innovative method for the quantification of HDV RNA allowing the independent quantification of edited and non-edited versions of the HDV genome upon infection. We demonstrated that FTI treatment of HBV/HDV co-infected dHepaRG or primary human hepatocytes leads to an accumulation of intracellular HDV RNAs and a marked increase in the levels of edited RNAs non only within the infected cells but also in the viral particles that are produced. Interestingly, these viral particles were less infectious, probably due to an enrichment in edited genomes that are packaged, leading to unproductive infection given the absence of S-HDAg synthesis after viral entry. Taken together, we setup an innovative quantification method allowing the investigation of RNA editing during HDV infection in a simple, fast, clinically-relevant assay and demonstrated for the first time the dual antiviral activity of FTI on HDV infection.

New actors come into play against hepatitis delta.

Currently chronic hepatitis delta (CHD) represents the most severe form of chronic viral hepatitis. The risk of developing cirrhosis, hepatocellular carcinoma (HCC) and decompensated liver disease is 2-3 times greater in hepatitis delta virus (HDV) infection than in hepatitis B virus (HBV). For instance, in a study carried out in Italy including 299 CHD patients followed for 28 years, 82 (27%) developed cirrhosis, and among these, 46 (56%) developed HCC. The real number of subjects infected by HDV worldwide remains unknown due to the lack of information in many areas, though it has been suggested that the rate of HBsAg carriers co-infected by HDV may be situated between 4.5 and 18%.

A Mathematical Model for Early HBV and -HDV Kinetics during Anti-HDV Treatment

Hepatitis delta virus (HDV) is an infectious subviral agent that can only propagate in people infected with hepatitis B virus (HBV). HDV/HBV infection is considered to be the most severe form of chronic viral hepatitis. In this contribution, a mathematical model for the interplay between HDV and HBV under anti-HDV treatment is presented. Previous models were not designed to account for the observation that HBV rises when HDV declines with HDV-specific therapy. In the simple model presented here, HDV and HBV kinetics are coupled, giving rise to an improved viral kinetic model that simulates the early interplay of HDV and HBV during anti-HDV therapy.