Outcome of chronic delta hepatitis in Italy: a long-term cohort study

Long-term outcome of hepatitis delta in different regions world-wide: Results of the Hepatitis Delta International Network

BACKGROUND AND AIMS

Chronic hepatitis delta represents a major global health burden. Clinical features of hepatitis D virus (HDV) infection vary largely between different regions worldwide. Treatment approaches are dependent on the approval status of distinct drugs and financial resources.

METHODS

The Hepatitis Delta International Network (HDIN) registry involves researchers from all continents (Wranke, Liver International 2018). We here report long-term follow-up data of 648 hepatitis D patients recruited by 14 centres in 11 countries. Liver-related clinical endpoints were defined as hepatic decompensation (ascites, encephalopathy and variceal bleeding), liver transplantation, hepatocellular carcinoma or liver-related death.

RESULTS

Patient data were available from all continents but Africa: 22% from Eastern Mediterranean, 32% from Eastern Europe and Central Asia, 13% from Central and Southern Europe, 14% from South Asia (mainly Pakistan) and 19% from South America (mainly Brazil). The mean follow-up was 6.4 (.6-28) years. During follow-up, 195 patients (32%) developed a liver-related clinical event after 3.5 (±3.3) years. Liver cirrhosis at baseline and a detectable HDV RNA test during follow-up were associated with a worse clinical outcome in multivariate regression analysis while patients receiving interferon alfa-based therapies developed clinical endpoints less frequently. Patients from South Asia developed endpoints earlier and had the highest mortality.

CONCLUSIONS

The HDIN registry confirms the severity of hepatitis D and provides further evidence for HDV viraemia as a main risk factor for disease progression. Hepatitis D seems to take a particularly severe course in patients born in Pakistan. There is an urgent need to extend access to antiviral therapies and to provide appropriate education about HDV infection.

Estimating the prevalence of hepatitis delta virus infection among adults in the United States: A meta-analysis

BACKGROUND AND AIMS

Suboptimal awareness and low rates of hepatitis delta virus (HDV) testing contribute to underdiagnosis and gaps in accurate estimates of U.S. HDV prevalence. We aim to provide an updated assessment of HDV prevalence in the U.S. using a comprehensive literature review and meta-analysis approach.

METHODS

A comprehensive literature review of articles reporting HBsAg seroprevalence and anti-HDV prevalence was conducted to calculate country-specific rates and pooled prevalence of CHB and HDV using meta-analyses. Country-specific CHB and HDV rate estimates were combined with number of foreign-born (FB) persons in the U.S. in 2022 from U.S. Census Bureau to estimate total numbers of FB with CHB and HDV, respectively. These estimates were further combined with updated estimates of U.S.-born persons with CHB and HDV to yield the total number of persons with CHB and HDV.

RESULTS

In 2022, we estimated 1.971 million (M) (95% CI 1.547-2.508) persons with CHB; 1.547 M (95% CI 1.264-1.831) were FB and 0.424 M (95% CI: 0.282-0.678) were U.S.-born. The weighted average HDV prevalence among FB persons in the U.S. was 4.20% (64 938 [95% CI 33055-97 392] persons), among whom 45% emigrated from Asia, 25% from Africa, and 14% from Europe. When combined with updated estimates of U.S.-born persons with HDV, we estimate 75 005 (95% CI: 42187-108 393) persons with HDV in the U.S.

CONCLUSIONS

Including both FB and U.S.-born persons, we estimated that 1.971 M and 75 005 persons were living with CHB and HDV, respectively, in the U.S. in 2022.

An updated assessment of hepatitis delta prevalence among adults in Canada: A meta-analysis

Foreign-born (FB) persons represent a large proportion of adults with chronic hepatitis B (CHB) in Canada due to higher prevalence rates in countries of birth for FB persons. Suboptimal awareness and low rates of hepatitis delta virus (HDV) testing contribute to underdiagnosis and gaps in accurate estimates of Canada HDV prevalence. We aim to provide an assessment of CHB and HDV prevalence in Canada using a comprehensive literature review and meta-analysis. A comprehensive literature review of articles reporting HBsAg seroprevalence and anti-HDV prevalence was conducted to calculate country-specific rates and pooled prevalence of CHB and HDV using meta-analyses. Country-specific CHB and HDV rate estimates were combined with number of FB persons in Canada in 2021 from Statistics Canada to estimate total numbers of FB with CHB and HDV, respectively. These estimates were combined with estimates of Canada-born persons with CHB and HDV to yield the total number of persons with CHB and HDV. In 2021, we estimated 0.550 million (M) (95% CI 0.488-0.615) persons with CHB; 0.344 M (95% CI 0.288-0.401) were FB and 0.206 M (95% CI: 0.200-0.214) were Canada-born. The weighted average HDV prevalence among FB persons in Canada was 5.19% (17,848 [95% CI 9611-26,052] persons), among whom 50% emigrated from Asia and 31% from Africa. When combined with estimates of Canada-born persons with HDV, we estimate 35,059 (95% CI: 18,744-52,083) persons with HDV in Canada. In conclusion, we estimate 0.550 M and 35,059 persons living with CHB and HDV, respectively, in Canada in 2021.

Association of hepatitis delta virus with liver morbidity and mortality: A systematic literature review and meta-analysis

BACKGROUND AND AIMS

Studies have suggested that patients with chronic hepatitis B, either co- or superinfected, have more aggressive liver disease progression than those with the HDV. This systematic literature review and meta-analysis examined whether HDV RNA status is associated with increased risk of advanced liver disease events in patients who are HBsAg and HDV antibody positive.

APPROACH AND RESULTS

A total of 12 publications were included. Relative rates of progression to advanced liver disease event for HDV RNA+/detectable versus HDV RNA-/undetectable were extracted for analysis. Reported OR and HRs with 95% CI were pooled using the Hartung-Knapp-Sidik-Jonkman method for random-effects models. The presence of HDV RNA+ was associated with an increased risk of any advanced liver disease event [random effect (95% CI): risk ratio: 1.48 (0.93, 2.33); HR: 2.62 (1.55, 4.44)]. When compared to the patients with HDV RNA- status, HDV RNA+ was associated with a significantly higher risk of progressing to compensated cirrhosis [risk ratio: 1.74 (1.24, 2.45)] decompensated cirrhosis [HR: 3.82 (1.60, 9.10)], HCC [HR: 2.97 (1.87, 4.70)], liver transplantation [HR: 7.07 (1.61, 30.99)], and liver-related mortality [HR: 3.78 (2.18, 6.56)].

CONCLUSIONS

The patients with HDV RNA+ status have a significantly greater risk of liver disease progression than the patients who are HDV RNA-. These findings highlight the need for improved HDV screening and linkage to treatment to reduce the risk of liver-related morbidity and mortality.

Hepatitis Delta Virus and Hepatocellular Carcinoma

The hepatitis D virus (HDV) is a compact, enveloped, circular RNA virus that relies on hepatitis B virus (HBV) envelope proteins to initiate a primary infection in hepatocytes, assemble, and secrete new virions. Globally, HDV infection affects an estimated 12 million to 72 million people, carrying a significantly elevated risk of developing cirrhosis, liver failure, and hepatocellular carcinoma (HCC) compared to an HBV mono-infection. Furthermore, HDV-associated HCC often manifests at a younger age and exhibits more aggressive characteristics. The intricate mechanisms driving the synergistic carcinogenicity of the HDV and HBV are not fully elucidated but are believed to involve chronic inflammation, immune dysregulation, and the direct oncogenic effects of the HDV. Indeed, recent data highlight that the molecular profile of HCC associated with HDV is unique and distinct from that of HBV-induced HCC. However, the question of whether the HDV is an oncogenic virus remains unanswered. In this review, we comprehensively examined several crucial aspects of the HDV, encompassing its epidemiology, molecular biology, immunology, and the associated risks of liver disease progression and HCC development.

The Role of Hepatitis Viruses as Drivers of Hepatocancerogenesis

Recently, metabolic associated steatotic liver disease (MASLD) became the leading cause of chronic liver disease worldwide and one of the most frequent causes of hepatocellular carcinoma (HCC). Nonetheless, in this epidemiological trend, viral hepatitis remains the major driver in hepatic carcinogenesis. Globally, hepatitis B virus (HBV) is the leading cause of hepatocellular carcinoma, with an overall attributable risk of approximately 40%, followed by hepatitis C virus (HCV), which accounts for 28-30% of cases, with significant geographic variations between the Eastern and Western world. Considering all the etiologies, HCC risk increases proportionally with the progression of liver disease, but the risk is consistently higher in patients with viral triggers. This evidence indicates that both direct (due to the oncogenic properties of the viruses) and indirect (through the mechanisms of chronic inflammation that lead to cirrhosis) mechanisms are involved, alongside the presence of co-factors contributing to liver damage (smoking, alcohol, and metabolic factors) that synergistically enhance the oncogenic process. The aim of this review is to analyze the oncogenic role of hepatitis viruses in the liver, evaluating epidemiological changes and direct and indirect viral mechanisms that lead to liver cancer.

Understanding the Natural History of Chronic Hepatitis D: Proposal of a Model for Cost-Effectiveness Studies

BACKGROUND

As new therapeutic options become available, better understanding the potential impact of emerging therapies on clinical outcomes of hepatits D virus (HDV) is critical.

OBJECTIVE

The aim of this study was to develop a natural history model for patients with hepatitis D virus.

METHODS

We developed a model (decision tree followed by a Markov cohort model) in adults with chronic HDV infection to assess the natural history and impact of novel treatments on disease progression versus best supportive care (BSC). The model time horizon was over a lifetime (up to 100 years of age); state transitions and health states were defined by responder status. Patients in fibrosis stages 0 through 4 received treatment; decompensated patients were not treated. Response was defined as the combined response endpoint of achievement of HDV-RNA undetectability/≥2-log10 decline and alanine aminotransferase normalization; response rates of 50% and 75% were explored. Health events associated with advanced liver disease were modeled as the number of events per 10,000 patients. Scenario analyses of early treatment, alternate treatment response, and no fibrosis regression for treatment responders were also explored.

RESULTS

The model was able to reflect disease progression similarly to published natural history studies for patients with HBV/HDV infection. In a hypothetical cohort of patients reflecting a population enrolled in a recent clinical trial, fewer advanced liver disease events were observed with a novel HDV treatment versus BSC. Fewer liver-related deaths were observed under 50% and 75% response (900 and 1,358 fewer deaths, respectively, per 10,000 patients). Scenario analyses showed consistently fewer advanced liver disease events with HDV treatment compared with BSC, with greater reductions observed with earlier treatment.

CONCLUSION

This HDV disease progression model replicated findings from natural history studies. Furthermore, it found that a hypothetical HDV treatment results in better clinical outcomes for patients versus BSC, with greater benefit observed when starting treatment early. This validated natural history model for HBV/HDV infection can serve as a foundation for future clinical and economic analyses of novel HDV treatments that can support healthcare stakeholders in the management of patients with chronic HDV.

Adjusted estimate of the prevalence of hepatitis delta virus in 25 countries and territories

BACKGROUND & AIMS

Hepatitis delta virus (HDV) is a satellite RNA virus that requires the hepatitis B virus (HBV) for assembly and propagation. Individuals infected with HDV progress to advanced liver disease faster than HBV-monoinfected individuals. Recent studies have estimated the global prevalence of anti-HDV antibodies among the HBV-infected population to be 5-15%. This study aimed to better understand HDV prevalence at the population level in 25 countries/territories.

METHODS

We conducted a literature review to determine the prevalence of anti-HDV and HDV RNA in hepatitis B surface antigen (HBsAg)-positive individuals in 25 countries/territories. Virtual meetings were held with experts from each setting to discuss the findings and collect unpublished data. Data were weighted for patient segments and regional heterogeneity to estimate the prevalence in the HBV-infected population. The findings were then combined with The Polaris Observatory HBV data to estimate the anti-HDV and HDV RNA prevalence in each country/territory at the population level.

RESULTS

After adjusting for geographical distribution, disease stage and special populations, the anti-HDV prevalence among the HBsAg+ population changed from the literature estimate in 19 countries. The highest anti-HDV prevalence was 60.1% in Mongolia. Once adjusted for the size of the HBsAg+ population and HDV RNA positivity rate, China had the highest absolute number of HDV RNA+ cases.

CONCLUSIONS

We found substantially lower HDV prevalence than previously reported, as prior meta-analyses primarily focused on studies conducted in groups/regions that have a higher probability of HBV infection: tertiary care centers, specific risk groups or geographical regions. There is large uncertainty in HDV prevalence estimates. The implementation of reflex testing would improve estimates, while also allowing earlier linkage to care for HDV RNA+ individuals. The logistical and economic burden of reflex testing on the health system would be limited, as only HBsAg+ cases would be screened.

IMPACT AND IMPLICATIONS

There is a great deal of uncertainty surrounding the prevalence of hepatitis delta virus among people living with hepatitis B virus at the population level. In this study, we aimed to better understand the burden in 25 countries and territories, to refine techniques that can be used in future analyses. We found a lower prevalence in the majority of places studied than had been previously reported. These data can help inform policy makers on the need to screen people living with hepatitis B virus to find those coinfected with hepatitis delta virus and at high risk of progression, while also highlighting the pitfalls that other researchers have often fallen into.

Hepatitis D: A Review

Importance

Hepatitis D virus (HDV) infection occurs in association with hepatitis B virus (HBV) infection and affects approximately 12 million to 72 million people worldwide. HDV causes more rapid progression to cirrhosis and higher rates of hepatocellular carcinoma than HBV alone or hepatitis C virus.

Observations

HDV requires HBV to enter hepatocytes and to assemble and secrete new virions. Acute HDV-HBV coinfection is followed by clearance of both viruses in approximately 95% of people, whereas HDV superinfection in an HBV-infected person results in chronic HDV-HBV infection in more than 90% of infected patients. Chronic hepatitis D causes more rapidly progressive liver disease than HBV alone. Approximately 30% to 70% of patients with chronic hepatitis D have cirrhosis at diagnosis and more than 50% die of liver disease within 10 years of diagnosis. However, recent studies suggested that progression is variable and that more than 50% of people may have an indolent course. Only approximately 20% to 50% of people infected by hepatitis D have been diagnosed due to lack of awareness and limited access to reliable diagnostic tests for the HDV antibody and HDV RNA. The HBV vaccine prevents HDV infection by preventing HBV infection, but no vaccines are available to protect those with established HBV infection against HDV. Interferon alfa inhibits HDV replication and reduces the incidence of liver-related events such as liver decompensation, hepatocellular carcinoma, liver transplant, or mortality from 8.5% per year to 3.3% per year. Adverse effects from interferon alfa such as fatigue, depression, and bone marrow suppression are common. HBV nucleos(t)ide analogues, such as entecavir or tenofovir, are ineffective against HDV. Phase 3 randomized clinical trials of bulevirtide, which blocks entry of HDV into hepatocytes, and lonafarnib, which interferes with HDV assembly, showed that compared with placebo or observation, these therapies attained virological and biochemical response in up to 56% of patients after 96 weeks of bulevirtide monotherapy and 19% after 48 weeks of lonafarnib, ritonavir, and pegylated interferon alfa treatment.

Conclusions and Relevance

HDV infection affects approximately 12 million to 72 million people worldwide and is associated with more rapid progression to cirrhosis and liver failure and higher rates of hepatocellular carcinoma than infection with HBV alone. Bulevirtide was recently approved for HDV in Europe, whereas pegylated interferon alfa is the only treatment available in most countries.

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

BACKGROUND AND AIMS

Hepatitis 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.

METHOD

We 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.

RESULTS

Clinical 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%).

CONCLUSION

Our 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.

Non-Invasive Prediction Scores for Hepatitis B Virus- and Hepatitis D Virus-Infected Patients-A Cohort from the North-Eastern Part of Romania

Approximately 62-72 million people are infected worldwide with HDV. Patients with chronic hepatitis D (CHD) have a higher risk of developing cirrhosis or hepatocellular carcinoma (HCC) and an increased mortality rate compared to those with chronic hepatitis B (CHB). The stage of liver fibrosis or the risk of developing HCC can also be estimated by non-invasive scores, which are cost effective, easier to apply, and reproducible. In this study, we aimed to evaluate the predictive value of four non-invasive scores (FIB-4, APRI, AST/ALT ratio, and aMAP) in assessing severe fibrosis/cirrhosis and the presence of HCC in patients with HBV/HDV superinfection, as compared with HBV mono-infection. Our 8-year retrospective analysis revealed that HDV-infected patients had a 2-3 times higher risk of developing cirrhosis and HCC than HBV-mono-infected subjects. High AST and ALT baseline levels qualified as independent predictors for cirrhosis development in both groups. The following fibrosis scores, FIB-4, APRI score, and AAR, were significantly increased when cirrhosis was present at baseline and showed a good prediction for developing cirrhosis in the CHD group. The aMAP score, a risk predictor for HCC, showed significantly higher values in patients with HCC in both groups. Nonetheless, non-invasive scores should always be considered for monitoring patients with CHB and CHD, but only when associated with other diagnosis methods.

Hepatitis delta: Epidemiology to recent advances in therapeutic agents

Hepatitis D virus (HDV) was first described in 1977 and is dependent on the presence of hepatitis B surface antigen (HBsAg) for its entry into cells and on the human host for replication. Due to the envelopment with the hepatitis B virus (HBV) envelope, early phases of HDV entry resemble HBV infection. Unlike HBV, HDV activates innate immune responses. The global prevalence of HDV is estimated to be about 5% of HBsAg positive individuals. However, recent studies have described a wide range of prevalence between 12 to 72 million individuals. Infection can occur as super-infection or co-infection. The diagnosis of active HDV infection involves screening with anti HDV antibodies followed by quantitative PCR testing for HDV RNA in those who are HBsAg positive. The diagnostic studies have evolved over the years improving the validity and reliability of the tests performed. HDV infection is considered the most severe form of viral hepatitis and the HDV genotype may influence the disease course. There are eight major HDV genotypes with prevalence varying by geographic region. HDV treatment has been challenging as HDV strongly depends on the host cell for replication and provides few, if any viral targets. Better understanding of HDV virology has led to the development of several therapeutic agents currently being studied in different phase II and III clinical trials. There is increasing promise of effective therapies that will ameliorate the course of this devastating disease.

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.

EASL Clinical Practice Guidelines on hepatitis delta virus

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

Hepatitis Delta Infection: A Clinical Review

First discovered over 40 years ago, the hepatitis delta virus (HDV) is a unique RNA virus, requiring hepatitis B virus (HBV) antigens for its assembly, replication, and transmission. HBV and HDV can be acquired at the same time (coinfection) or HDV infection can occur in persons with chronic HBV (superinfection). Screening guidelines for HDV are inconsistent. While some guidelines recommend universal screening for all people with HBV, others recommend risk-based screening. Estimates of the global HDV prevalence range from 4.5 to 14.6% among persons with HBV; thus, there may be up to 72 million individuals with HDV worldwide. HDV is the most severe form of viral hepatitis. Compared to HBV monoinfection, HDV coinfection increases the risk of cirrhosis, hepatocellular carcinoma, hepatic decompensation, mortality, and necessity for liver transplant. Despite the severity of HDV, there are few treatment options. Pegylated interferon (off-label use) has long been the only available treatment, although bulevirtide is conditionally approved in some European countries. There are many potential treatments in development, but as yet, there are few effective and safe therapies for HDV infection. In conclusion, given the severity of HDV disease and the paucity of treatments, there is a great unmet need for HDV therapies.

Hepatocellular carcinoma: The virus or the liver?

Hepatocellular carcinoma (HCC) represents a major public health problem being one of the most common causes of cancer-related deaths worldwide. Hepatitis B (HBV) and C viruses have been classified as oncoviruses and are responsible for the majority of HCC cases, while the role of hepatitis D virus (HDV) in liver carcinogenesis has not been elucidated. HDV/HBV coinfection is related to more severe liver damage than HBV mono-infection and recent studies suggest that HDV/HBV patients are at increased risk of developing HCC compared to HBV mono-infected patients. HBV is known to promote hepatocarcinogenesis via DNA integration into host DNA, disruption of molecular pathways by regulatory HBV x (HBx) protein and excessive oxidative stress. Recently, several molecular mechanisms have been proposed to clarify the pathogenesis of HDV-related HCC including activation of signalling pathways by specific HDV antigens, epigenetic dysregulation and altered gene expression. Alongside, ongoing chronic inflammation and impaired immune responses have also been suggested to facilitate carcinogenesis. Finally, cellular senescence seems to play an important role in chronic viral infection and inflammation leading to hepatocarcinogenesis. In this review, we summarize the current literature on the impact of HDV in HCC development and discuss the potential interplay between HBV, HDV and neighbouring liver tissue in liver carcinogenesis.

Natural history of untreated HDV patients: Always a progressive disease?

A severe course has been described in early studies on chronic hepatitis D (CHD), with faster pace towards liver cirrhosis with subsequent high liver-related morbidity and mortality in the majority of patients. Earlier studies have included risk groups as people using intravenous drugs (PWID) or those with multiple co-morbidities. During the last decade, the epidemiological landscape of CHD has changed with domestic cases decreasing while increasing cases of CHD consisting of younger persons immigrating from endemic regions to low-endemic regions. Recently, further insights into the spectrum of the disease with an indolent disease course in a substantial proportion of persons with CHD have been gained. At diagnosis, ≥30%-50% had already established liver cirrhosis. Older age, liver cirrhosis, co-infection with HIV and lack of interferon (IFN) therapy are the main predictors of worse clinical outcome. The newly introduced and upcoming antivirals against CHD are highly anticipated, considering the historically low virological response rates to antiviral therapy. Further knowledge is needed to fully comprehend the natural course and the spectrum of this severe form of viral hepatitis. This is also to be able to evaluate the long-term effects of the new antivirals on disease progression.

Bile acid increase during bulevirtide treatment of hepatitis D is not associated with a decline in HDV RNA

Bulevirtide (BLV) is an entry inhibitor blocking entry of HBsAg into hepatocytes by interfering with the bile acid transporter Na+-taurocholate co-transporting polypeptide. We here investigated if bile acid levels before or during BLV treatment would correlate with HDV RNA declines. We studied 20 patients with compensated HDV infection receiving a daily dose of 2 mg bulevirtide subcutaneously qd for at least 24 weeks. ALT levels improved in all patients including 13/20 patients showing normal ALT values at treatment Week 24. An HDV RNA drop of at least 50% was evident in 20/20 patients at Week 24 including 10 patients showing a ≥ 2 log HDV RNA decline. Elevated bile acid levels were detected already before treatment in 10 patients and further increased during BLV administration with different kinetics. Baseline bile acids were associated with higher transient elastography values (p = .0029) and evidence of portal hypertension (p = .0004). Bile acid levels before treatment were associated with HDV RNA declines throughout therapy, but not at Week 24 (rho = -0.577; p = .0078; rho = -0.635, p = .0026; rho = -0.577, p = .0077; rho = -0.519, p = .0191; rho = -0.564, p = .0119 and rho = -0.393, p = .087 at treatment Weeks 2, 8, 12, 16, 20 and 24, respectively). However, bile acid increases during treatment were not associated with HDV RNA or ALT declines at any of the time points. BLV-induced increases in bile salts do not correlate with HDV RNA declines suggesting that the inhibitory effects of BLV on NTCP differ between blocking bile acid transport and hindering HBsAg entry. If baseline bile salt levels could be useful to predict virological response remains to be confirmed.

Non-organ-specific autoantibodies with unspecific patterns are a frequent para-infectious feature of chronic hepatitis D

Infections with hepatotropic viruses are associated with various immune phenomena. Hepatitis D virus (HDV) causes the most severe form of viral hepatitis. However, few recent data are available on non-disease-specific and non-organ-specific antibody (NOSA) titers and immunoglobulin G (IgG) levels in chronic hepatitis D (CHD) patients. Here, we examined the NOSA titers and IgG levels of 40 patients with CHD and different disease courses and compared them to 70 patients with chronic hepatitis B (CHB) infection. 43% of CHD patients had previously undergone treatment with pegylated interferon-α (IFN-α). The antibody display of 46 untreated patients diagnosed with autoimmune hepatitis (AIH) was used as a reference. The frequency of elevated NOSA titers (CHD 69% vs. CHB 43%, p < 0.01), and the median IgG levels (CHD 16.9 g/L vs. CHB 12.7 g/L, p < 0.01) were significantly higher in CHD patients than in patients with CHB, and highest in patients with AIH (96%, 19.5 g/L). Also, the antinuclear antibody pattern was homogeneous in many patients with AIH and unspecific in patients with viral hepatitis. Additionally, f-actin autoantibodies were only detectable in patients with AIH (39% of SMA). In CHD patients, IgG levels correlated with higher HDV viral loads, transaminases, and liver stiffness values. IgG levels and NOSA were similar in CHD patients irrespective of a previous IFN-α treatment. In summary, autoantibodies with an unspecific pattern are frequently detected in CHD patients with unclear clinical relevance.

Current Therapy of Chronic Viral Hepatitis B, C and D

The majority of chronic viral hepatitis cases are induced via infection with the hepatitis B virus (HBV), hepatitis C virus (HCV), or hepatitis D virus (HDV). These patients are at increased risk for progressive liver disease leading to cirrhosis as well as hepatocellular carcinoma (HCC). HBV infection is well controlled by the currently available nucleosides as well as nucleotides, and the development of cirrhosis can be prevented. Additionally, it has been shown that HBV-induced liver fibrosis can regress during successful antiviral treatment; however, a "functional cure", i.e., loss of HBsAg, is a rare event when these drugs are used. Therefore, novel therapeutic strategies are aiming at the selective suppression of HBsAg levels in combination with immunostimulation. The development of directly acting antivirals (DAAs) has revolutionized HCV therapy, as almost all patients can be cured via this treatment. Additionally, DAA therapy has few, if any, side effects, and is generally well tolerated by patients. HDV remains the most challenging type of chronic viral hepatitis. Although novel therapeutic options have recently been approved, response rates are still less favorable compared to HBV and HCV. This review discusses current and future options for the treatment of chronic HBV, HCV, and HDV infection.

HDV RNA Levels and Progression of Hepatitis Delta Infection: A 14 Year Follow Up Experience in Italy

BACKGROUND

Identification of outcome predictors is one of the unmet needs in chronic HDV infection. Until recently, no reliable quantitative assays for HDV RNA were available.

AIMS

To evaluate the impact of baseline viremia on natural history of HDV infection in a cohort of patients whose serum samples were stored at their first visit 15 years ago.

METHODS

Quantitative HBsAg, HBeAg, HBeAb, HBV DNA, HDV RNA, genotypes, and liver disease severity were assessed at baseline. Patients who were no longer on active follow-up were recalled and re-evaluated in August 2022.

RESULTS

The majority of patients were male (64.9%); the median age was 50.1 years; and all patients were Italian, with only three born in Romania. All were HBeAg negative with HBV genotype D infection. Patients were subdivided three groups: 23 were in active follow-up (Group 1), 21 were recalled due to no longer being in follow-up (Group 2), and 11 died (Group 3). Liver cirrhosis was diagnosed in 28 subjects at the first visit; 39.3% of diagnosed patients were in Group 3, 32.1% were in Group 1 and 28.6% were in Group 2 (p = 0.001). Baseline HBV DNA IU/mL Log10 were 1.6 (1.0-5.9) in Group 1, 1.3 (1.0-4.5) in Group 2, and 4.1 (1.5-4.5) in Group 3; median baseline HDV RNA Log10 levels were 4.1 (0.7-6.7) in Group 1, 3.2 (0.7-6.2) in Group 2, and 5.2 (0.7-6.7) in Group 3, resulting significantly higher rates among patients in Group 3 compared to the other groups (p = 0.038). Eighteen patients in Group 2, as compared to 7 in Group 1, had undetectable HDV RNA at the follow-up evaluation (p = 0.001).

CONCLUSIONS

HDV chronic infection is a heterogeneous disease. It may not only progress but also improve over time in patients, who eventually become HDV RNA-undetectable. HDV RNA levels may help identify the subgroup of patients with less progressive liver disease.

Hepatitis delta coinfection in persons with HIV: misdiagnosis and disease burden in Italy

Hepatitis Delta virus (HDV) causes severe liver disease. Due to similarities in transmission routes, persons living with HIV (PLWH) are at risk of HDV infection. This analysis investigates the prevalence and the long-term clinical outcome of people with HDV in a large cohort of PLWH. We retrieved HBsAg ± anti-HDV positive PLWH enrolled from 1997 to 2015 in the multicentre, prospective ICONA study. The primary endpoint was a composite clinical outcome (CCO = having experienced ≥1 of the following: Fib4 score >3.25; diagnosis of cirrhosis; decompensation; hepatocellular carcinoma or liver-related death). Kaplan-Meier curves and unweighted and weighted Cox regression models were used for data analysis. Less than half of HBsAg positive patients had been tested for anti-HDV in clinical practice. After testing stored sera, among 617 HBV/HIV cases, 115 (19%) were anti-HDV positive; 405 (65%) HBV monoinfected; 99 (16%) undeterminate. The prevalence declined over the observation period. HDV patients were more often males, intravenous drug users, HCV coinfected. After a median of 26 months, 55/115 (48%) developed CCO among HDV+; 98/403 (24%) among HBV monoinfected; 18/99 (18%) in HDV unknown (p < 0.001). After controlling for geographical region, alcohol consumption, CD4 count, anti-HCV status and IFN-based therapies, the association with HDV retained statistical significance [HR = 1.67 (1.15, 2.95; p = 0.025)]. HDV infection among PLWH is underdiagnosed, although HDV entails an high risk of liver disease progression. Because effective drugs to treat HDV are now available, it is even more crucial to identify PLWH at an early stage of liver disease.

Hepatitis delta virus: Disease assessment and stratification

Hepatitis D virus (HDV) causes one of the most severe forms of hepatitis in people with chronic hepatitis B (CHB) infection. Timely and accurate assessment of hepatitis delta virus (HDV) and disease stratification is mandatory for thorough pre-therapeutic evaluation for prioritizing treatment and outcome prediction. Viral biomarkers associated with HDV and hepatitis B virus (HBV) are crucial to aid in diagnosis, and monitoring of serum viral nucleic acids for both viruses is recommended. Liver biopsy remains the gold standard for staging of liver fibrosis and grading of histological activity and should remain central for diagnostic purposes, but is also of importance for research to enhance our understanding of HDV. The emergence of novel non-invasive tests for the assessment of liver fibrosis in HDV patients coupled with the well-recognized potential complications of liver biopsy has resulted in reduced utility of liver biopsy in clinical practice. Preliminary data suggest that these emerging non-invasive modalities appear to be reliable, and their use is supported, similar to other viral hepatitis. Nevertheless, further validation is required before their widespread adoption into clinical practice.

Low Performance of Hepatitis Delta Virus Testing Among 2 National Cohorts of Chronic Hepatitis B Patients in the United States

INTRODUCTION

The purpose of this study was to evaluate hepatitis delta virus (HDV) testing patterns among US adults with chronic hepatitis B (CHB).

METHODS

HDV testing was evaluated among CHB patients using Quest Diagnostics (2016-2020) and Veterans Affairs (2010-2020) data.

RESULTS

Among 157,333 CHB patients (Quest), 6.7% received HDV testing, among which 2.2% were positive. HDV testing was higher in male patients, younger individuals, and patients with advanced liver disease. Among 12,002 CHB patients (Veterans Affairs), 19.7% received HDV testing, among which 3.1% were positive. HDV testing was higher in younger individuals and Asians.

DISCUSSION

Low HDV testing was observed among 2 large US cohorts of adults with CHB.

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.

Clinical and virological features of chronic hepatitis B in the French National Surveillance Program, 2008-2012

Background & Aims

Among people living with HBV, only a subset of individuals with chronic hepatitis is in need of treatment, and this proportion varies according to the population, region, and setting. No estimates of the proportion of people who are infected with HBV and meet the treatment eligibility criteria in France are available.

Methods

552 treatment-naïve individuals with chronic HBV infection referred for the first time to a hepatology reference centre between 2008 and 2012 were prospectively included. Demographic, clinical, and laboratory data were analysed.

Results

In total, 61.1% of patients were males, with a median age of 37.5 years. Moreover, 64% were born in an intermediate- or high-HBV endemicity country, and 90% were HBeAg-negative. At referral, median HBV DNA and HBsAg levels were 3.3 and 3.6 log IU/ml, respectively; 37.8% of patients had alanine aminotransferase >40 U/L, and 29.0% had moderate or severe fibrosis (≥F2), including 9.4% with cirrhosis. The most prevalent genotypes were D (34.7%), E (27.4%), and A (25.7%). Coinfections were rare: 2.4% were HIV-positive, 4.0% were HCV-positive, and 6.0% were HDV-positive. According to the 2017 EASL Clinical Practice Guidelines, using a single time point analysis, 2.7% of patients were classified as HBeAg-positive chronic infection, 6.1% as HBeAg-positive chronic hepatitis B, 26.5% as HBeAg-negative chronic hepatitis B, and 61.1% as HBeAg-negative chronic infection, whereas 3.6% patients could not be classified. The performance of HBsAg level quantification to identify individuals with HBeAg-negative chronic hepatitis B was poor. A total of 29.1% met the criteria for initiation of antiviral treatment, whereas 66.5% remained under routine clinical surveillance. Most eligible patients initiated recommended first-line therapies, including tenofovir (45.3%), entecavir (36.8%), or pegylated interferon alpha (11.6%).

Conclusions

Of all cases, 9.4% had cirrhosis at presentation and 29.1% met the 2017 EASL Clinical Practice Guidelines treatment criteria. HBsAg levels failed to accurately identify individuals with HBeAg-negative chronic infection.

Lay summary

Among French adults chronically infected with HBV referred for the first time to hepatology reference centres, about one-third had a significant liver disease. Approximately one-third of individuals met criteria for initiation of antiviral treatment based on entecavir or tenofovir or, occasionally, pegylated interferon alpha.

•

In French adults with chronic hepatitis B infection, the most prevalent genotypes were D, E, and A.

•

Patients were predominantly HBeAg-negative (90.0%).

•

The seroprevalence of delta hepatitis was 6%.

•

HBsAg quantification is not useful in identifying patients with HBeAg-negative chronic hepatitis B.

•

A total of 29.1% of patients were eligible for antiviral treatment.

A Review of HDV Infection

Hepatitis D is the most severe viral hepatitis. Hepatitis D virus (HDV) has a very small RNA genome with unique biological properties. It requires for infection the presence of hepatitis B virus (HBV) and is transmitted parenterally, mainly by superinfection of HBsAg carriers who then develop chronic hepatitis D. HDV has been brought under control in high-income countries by the implementation of HBV vaccination, and the clinical pattern has changed to a chronic hepatitis D seen in ageing patients with advanced fibrotic disease; the disease remains a major health concern in developing countries of Africa and Asia. Every HBsAg-positive subject should be tested for HDV serum markers by reflex testing, independently of clinical status. Vaccination against HBV provides the best prophylaxis against hepatitis D. The only therapy available so far has been the poorly performing Interferon alfa; however, several new and promising therapeutic approaches are under study.

Advancements in the prevention of hepatitis B recurrence by nucleos(t)ide analogue monotherapies after liver transplantation

Previous studies have shown that the recurrence rate of HBV (hepatitis B virus) after liver transplantation (LT) can be as high as 80% without any preventive measures. Therefore, prevention of HBV recurrence after LT is always an essential part of clinical work worldwide. The NAs that have been approved for HBV treatment include lamivudine, adefovir dipivoxil, entecavir (ETV), and telbivudine, tenofovir disoproxil fumarate (TDF), and tenofovir alafenamide (TAF). They are often combined with HBIG to prevent HBV recurrence after LT clinically. However, NAs with a higher genetic barrier, such as ETV, TDF, and TAF, can improve liver function by strongly inhibiting HBV replication and reducing the risks of HBV resistance. Recently, some NAs with a higher genetic barrier, such as ETV, TDF, and TAF, have been adopted as monotherapy for preventing the recurrence of hepatitis B after LT in multiple organ transplant centres and have achieved effective outcomes. This article aims to review the advances for NAs monotherapy in prophylaxis for HBV recurrence after LT.

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.

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.

The hepatitis D virus in Italy. A vanishing infection, not yet a vanished disease

Introduction

Hepatitis D Virus (HDV) infection is vanishing in Italy. It is therefore believed that hepatitis D is no longer a medical problem in the domestic population of the country but remains of concern only in migrants from HDV-endemic areas.

Objectives

To report the clinical features and the medical impact of the residual domestic HDV infections in Italy.

Methods

From 2010 to 2019, one hundred ninety-three first-time patients with chronic HDV liver disease attended gastroenterology units in Torino and San Giovanni Rotondo (Apulia); 121 were native Italians and 72 were immigrants born abroad. For this study, we considered the 121 native Italians in order to determine their clinical features and the impact of HDV disease in liver transplant programs.

Results

At the last observation the median age of the 121 native Italians was 58 years. At the end of the follow-up, the median liver stiffness was 12.0 kPa (95% CI 11.2-17.4), 86 patients (71.1%) had a diagnosis of cirrhosis; 80 patients (66.1%) remained HDV viremic. The ratio of HDV to total HBsAg transplants varied from 38.5% (139/361) in 2000-2009 to 50.2% (130/259) in 2010-2019, indicating a disproportionate role of hepatitis D in liver transplants compared to the minor prevalence of HDV infections in the current scenario of HBsAg-positive liver disorders in Italy.

Conclusion

Though HDV is vanishing in Italy, a legacy of ageing native-Italian patients with advanced HDV liver disease still represents an important medical issue and maintains an impact on liver transplantation.

Risk of hepatocellular carcinoma in hepatitis B and D virus co-infected patients: A systematic review and meta-analysis of longitudinal studies

Hepatitis D virus (HDV) infection causes a severe chronic viral hepatitis with accelerated development of liver cirrhosis and decompensation, but whether it further increases the risk of hepatocellular carcinoma (HCC) is unclear. We performed a comprehensive systematic review of the published literature and meta-analysis to assess the risk of HCC in HDV and hepatitis B virus (HBV) co-infected, compared to HBV mono-infected patients. The study was conducted per a priori defined protocol, including only longitudinal studies, thus excluding cross-sectional studies. Random-effects models were used to determine aggregate effect sizes (ES) with 95% confidence intervals (CI). Meta-regression was used to examine the associations among study level characteristics. Twelve cohort studies comprising a total of 6099 HBV/HDV co-infected and 57,620 chronic HBV mono-infected patients were analysed. The overall pooled ES showed that HBV/HDV co-infected patients were at 2-fold increased risk of HCC compared to HBV mono-infected patients (ES = 2.12, 95% CI 1.14-3.95, I²  = 72%, N = 12). A six-fold significant increased risk of HCC was noted among HIV/HBV/HDV triple-infected, compared to HIV/HBV co-infected patients. The magnitude of ES did not differ significantly after adjustment for study design and quality, publication year and follow-up duration in univariable meta-regression analysis. This systematic review and meta-analysis shows that infection with HDV is associated with a 2-fold higher risk of HCC development compared to HBV mono-infection. HCC surveillance strategies taking this increased risk into account, and new treatment options against HDV, are warranted.

Poor clinical and virological outcome of nucleos(t)ide analogue monotherapy in HBV/HDV co-infected patients

Co-infection of Hepatitis B (HBV) and Delta viruses (HDV) represent the most severe form of viral hepatitis. While treatment with pegylated Interferon alpha (PEG-IFNα) is well established, therapy with nucleoside or nucleotide analogues (NA) has been a matter of debate. We aimed to investigate the role of NA treatment in a well-defined single centre cohort.In a retrospective approach, we observed 53 HDV RNA positive and/or anti-HDV-positive patients recruited at a German referral centre between 2000 and 2019. Patients were followed for at least 3 months (mean time of follow up: 4.6 years; range: 0.2-14.1 years). Patients who had liver transplantation or hepatocellular carcinoma at the time of presentation were excluded. 43% (n = 23) were treated with NA, 43% (n = 23) received IFNα-based therapies and 13% (n = 7) were untreated.Liver cirrhosis was already present in 53% (28/53) of patients at first presentation. During follow-up, liver-related endpoints developed in 44% of all patients (n = 23). NA-treatment was associated with a significantly worse clinical outcome (P = .01; odds ratio [OR] = 4.92; CI = 1.51-16.01) compared to both, untreated (P = .38; OR = 0.46; CI = 0.80-2.61) and IFNα-based-treated patients (P = .04; OR = 0.29; CI = 0.89-0.94) in univariate logistic regression analysis. HBsAg levels declined by more than 50% during NA-based therapy in only 7 cases (7/23; mean time: 3.6 years; range: 0.8-8.5 years) and during IFNα-based therapy in 14 cases (14/23; mean time: 2.8 years, range 0.7-8.5 years). HDV RNA became undetectable during follow up in 30% of patients receiving NA alone (7/23; mean time: 5.0 years; range: 0.6-13.5 years), in 35% of patients receiving IFNα-based therapy (8/23; mean time: 2.9 years, range: 0.3-7.6 years).The effect of NA in patients with HBV/HDV co-infection is limited. Treatment with NA was associated with a higher likelihood of clinical disease progression. Interferon alpha therapy was beneficial in reducing liver complications and improves long-term outcome.

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.

Investigating the prevalence and clinical effects of hepatitis delta viral infection in Taiwan

PURPOSE

To clarify and investigate the prevalence and clinical impact of hepatitis D virus (HDV) infection in Taiwan's communities.

METHODS

HDV infection in patients with chronic hepatitis B viral (HBV) infection was examined using an anti-HDV antibody in Yonghe Cardinal Tien Hospital (YCTH), a district hospital in Taiwan. Clinical characteristics of anti-HDV-positive and anti-HDV-negative patients were collected and compared. These characteristics were also compared with the data collected from a medical center. Continuous variables and confounding factor adjustments were compared using the analysis of covariance method, whereas categorical variables were compared using the logistic regression method.

RESULTS

A total of 346 patients with chronic HBV infection were assessed from 2018 to 2019. Among them, 4 (1.15%) were positive for anti-HDV. The clinical, virological, and biochemical characteristics were similar between anti-HDV-positive and anti-HDV-negative groups. None of the four patients was positive for serum HDV RNA. Another 18 anti-HDV-positive patients were identified from National Taiwan University Hospital (NTUH). The clinical, virological, and biochemical characteristics of anti-HDV-positive patients from YCTH and NTUH were also similar.

CONCLUSION

The prevalence of HDV and the serum HDV RNA-positive rate were low in district hospitals in Taiwan. Coexisting HDV infection did not influence the clinical manifestation of patients with chronic HBV infection in Taiwan. However, because the number of HDV RNA cases was very small, our findings may not be conclusive. Besides, since the sensitivity of current anti-HDV kit is not 100%, more sensitive methods are needed to achieve reliable prevalence data.

Hepatitis D Virus and Hepatocellular Carcinoma

Hepatitis D virus (HDV) is a small, defective RNA virus that depends on hepatitis B virus (HBV) for virion assembly and transmission. It replicates within the nucleus of hepatocytes and interacts with several cellular proteins. Chronic hepatitis D is a severe and progressive disease, leading to cirrhosis in up to 80% of cases. A high proportion of patients die of liver decompensation or hepatocellular carcinoma (HCC), but the lack of large prospective studies has made it difficult to precisely define the rate of these long-term complications. In particular, the question of whether HDV is an oncogenic virus has been a matter of debate. Studies conducted over the past decade provided evidence that HDV is associated with a significantly higher risk of developing HCC compared to HBV monoinfection. However, the mechanisms whereby HDV promotes liver cancer remain elusive. Recent data have demonstrated that the molecular profile of HCC-HDV is unique and distinct from that of HBV-HCC, with an enrichment of upregulated genes involved in cell-cycle/DNA replication, and DNA damage and repair, which point to genome instability as an important mechanism of HDV hepatocarcinogenesis. These data suggest that HBV and HDV promote carcinogenesis by distinct molecular mechanisms despite the obligatory dependence of HDV on HBV.

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.

HDV Pathogenesis: Unravelling Ariadne's Thread

Hepatitis Delta virus (HDV) lies in between satellite viruses and viroids, as its unique molecular characteristics and life cycle cannot categorize it according to the standard taxonomy norms for viruses. Being a satellite virus of hepatitis B virus (HBV), HDV requires HBV envelope glycoproteins for its infection cycle and its transmission. HDV pathogenesis varies and depends on the mode of HDV and HBV infection; a simultaneous HDV and HBV infection will lead to an acute hepatitis that will resolve spontaneously in the majority of patients, whereas an HDV super-infection of a chronic HBV carrier will mainly result in the establishment of a chronic HDV infection that may progress towards cirrhosis, liver decompensation, and hepatocellular carcinoma (HCC). With this review, we aim to unravel Ariadne’s thread into the labyrinth of acute and chronic HDV infection pathogenesis and will provide insights into the complexity of this exciting topic by detailing the different players and mechanisms that shape the clinical outcome.

Genomics of Viral Hepatitis-Associated Liver Tumors

Virus-related liver carcinogenesis is one of the main contributors of cancer-related death worldwide mainly due to the impact of chronic hepatitis B and C infections. Three mechanisms have been proposed to explain the oncogenic properties of hepatitis B virus (HBV) infection: induction of chronic inflammation and cirrhosis, expression of HBV oncogenic proteins, and insertional mutagenesis into the genome of infected hepatocytes. Hepatitis B insertional mutagenesis modifies the function of cancer driver genes and could promote chromosomal instability. In contrast, hepatitis C virus promotes hepatocellular carcinoma (HCC) occurrence mainly through cirrhosis development whereas the direct oncogenic role of the virus in human remains debated. Finally, adeno associated virus type 2 (AAV2), a defective DNA virus, has been associated with occurrence of HCC harboring insertional mutagenesis of the virus. Since these tumors developed in a non-cirrhotic context and in the absence of a known etiological factor, AAV2 appears to be the direct cause of tumor development in these patients via a mechanism of insertional mutagenesis altering similar oncogenes and tumor suppressor genes targeted by HBV. A better understanding of virus-related oncogenesis will be helpful to develop new preventive strategies and therapies directed against specific alterations observed in virus-related HCC.

[Clinical course and outcomes of chronic viral hepatitis D in patients from Republic of Tuva as endemic region]

INTRODUCTION

Hepatitis D (delta, 5) is caused by an RNA virus (hepatitis D virus, HDV) from genus Deltavirus, and is the most severe and difficult to treat disease among both viral hepatitis and infectious diseases in general. The development of HDV infection in the host organism is possible only in the presence of hepatitis B virus (HBV). Coinfection with HBV and HDV is associated with a more rapid progression of chronic viral hepatitis (CVH) to liver cirrhosis (LC) and an unfavorable outcome in comparison with HBV monoinfection. Data on the influence of clinical, biochemical and virological factors on the infectious process in patients with hepatitis D are limited due to the insufficient amount of research on this theme.The study aimed to determine demographic, clinical, biochemical, and virological factors influencing the course and progression of CVH D in patients followed during 10 years, residing in the territory of the Tuva Republic, one of the endemic regions of the Russian Federation.

MATERIAL AND METHODS

Changes in clinical and laboratory parameters were analyzed in dynamics in 121 HDV infected patients with a different course of the disease, who were under observation from 2009 to 2019. Three groups of patients were identified: group 1 - 61 patients with disease progression of chronic hepatitis to LC (Child-Pugh class B-C), group 2 - 49 patients with non-progressive chronic hepatitis, and group 3 - 11 patients with slowly progressive LC (class A). Demographic data, the presence of detectable HBV DNA, indicators of the functional state of the liver: alanine aminotransferase (ALT/GPT), aspartate aminotransferase (AST/GOT), alkaline phosphatase (ALP), gamma-glutamyltransferase (GGT), and total bilirubin content were analyzed. The severity of hepatic encephalopathy was assessed by the duration of the numbers connection test (NCT).

RESULTS

All patients belonged to the same ethnic group (Tuvinians), were infected with HDV genotype 1 and were positive for HDV RNA throughout the entire follow-up period. There were no significant differences in sex ratio and mean age at the time of inclusion in the study between the groups. In group 1, the average number of years from inclusion in the study to the formation of LC was 3.65 ± 2.3 years, years to the lethal outcome: 4.5 ± 3 years. Significantly higher levels of AST/GOT, ALP, GGT, total bilirubin (TB) and NCT grade were found in group 1 compared to group 2. ALT/GPT levels did not differ significantly in these groups. When comparing groups with disease progression and slowly progressive LC (groups 1 and 3), no significant differences were found in any of the clinical and biochemical parameters. ALT/GPT, GGT, TB and NCT values were significantly higher in patients with slowly progressive LC (group 3) compared to group 2. No differences in AST/GOT and ALP levels were found between these groups. Detectable HBV DNA was significantly more frequent in patients with progressive disease and with chronic viral hepatitis than in patients with slowly progressive LC. There were no significant differences in the frequency of HBV DNA detection in patients from groups 1 and 2.

CONCLUSION

The results obtained on a relatively homogeneous cohort demonstrated that age and gender are not the factors influencing the progression of chronic viral hepatitis D to cirrhosis. The lack of detectable HBV DNA is associated with the slow progression of LC. The revealed differences in clinical and biochemical parameters reflect the degree of functional liver damage in chronic viral hepatitis D and HDV-associated cirrhosis.

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.

Origin, HDV genotype and persistent viremia determine outcome and treatment response in patients with chronic hepatitis delta

BACKGROUND & AIMS

HDV infection causes severe chronic liver disease in individuals infected with HBV. However, the factors associated with poor prognosis are largely unknown. Thus, we aimed to identify prognostic factors in patients with HDV infection.

METHODS

The French National Reference Centre for HDV performed a nationwide retrospective study on 1,112 HDV-infected patients, collecting epidemiological, clinical, virological and histological data from the initial referral to the last recorded follow-up.

RESULTS

The median age of our cohort was 36.5 (29.9-43.2) years and 68.6% of our cohort were male. Most patients whose birthplace was known were immigrants from sub-Saharan Africa (52.5%), southern and eastern Europe (21.3%), northern Africa and the Middle East (6.2%), Asia (5.9%) and South America (0.3%). Only 150 patients (13.8%) were French native. HDV load was positive in 659 of 748 tested patients (88.1%). HDV-1 was predominant (75.9%), followed by sub-Saharan genotypes: HDV-5 (17.6%), HDV-7 (2.9%), HDV-6 (1.8%) and HDV-8 (1.6%). At referral, 312 patients (28.2%) had cirrhosis, half having experienced at least 1 episode of hepatic decompensation. Cirrhosis was significantly less frequent in African than in European patients regardless of HDV genotype. At the end of follow-up (median 3.0 [0.8-7.2] years), 48.8% of the patients had developed cirrhosis, 24.2% had ≥1 episode(s) of decompensation and 9.2% had hepatocellular carcinoma. European HDV-1 and African HDV-5 patients were more at risk of developing cirrhosis. Persistent replicative HDV infection was associated with decompensation, hepatocellular carcinoma and death. African patients displayed better response to interferon therapy than non-African patients (46.4% vs. 29.1%, p <0.001). HDV viral load at baseline was significantly lower in responders than in non-responders.

CONCLUSION

Place of birth, HDV genotype and persistent viremia constitute the main determinants of liver involvement and response to treatment in chronic HDV-infected patients.

LAY SUMMARY

Chronic liver infection by hepatitis delta virus (HDV) is the most severe form of chronic viral hepatitis. Despite the fact that at least 15-20 million people are chronically infected by HDV worldwide, factors determining the severity of liver involvement are largely unknown. By investigating a large cohort of 1,112 HDV-infected patients followed-up in France, but coming from different areas of the world, we were able to determine that HDV genotype, place of birth (reflecting both viral and host-related factors) and persistent viremia constitute the main determinants of liver involvement and response to treatment.

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.

Chronic hepatitis D and hepatocellular carcinoma: A systematic review and meta-analysis of observational studies

BACKGROUND & AIMS

Chronic hepatitis D (CHD) is the most severe form of chronic viral hepatitis but its role in the development of hepatocellular carcinoma (HCC) remains debated. We conducted a systematic review and meta-analysis of epidemiological studies to examine whether CHD is associated with an increased risk of HCC.

METHODS

We searched PubMed, Embase and Web of Science, as well as study references and conference proceedings. We considered cohort and case-control studies allowing the calculation of effect estimates for the association between CHD (exposure) and HCC (outcome) in comparison to chronic hepatitis B. Data extraction and quality evaluation (using the Newcastle-Ottawa scale) were performed independently by 2 authors. Data were pooled using random-effects models.

RESULTS

Ninety-three studies (68 case-control studies including 22,862 patients and 25 cohort studies including 75,427 patients) were included. Twelve studies accounted for confounders, in either study design or analysis (10 of which were cohorts), and 11 cohorts were prospective. The overall analysis showed a significantly increased risk of HCC in patients with CHD, despite substantial study heterogeneity (pooled odds ratio 1.28; 95% CI 1.05-1.57; I² = 67.0%). The association was particularly strong in the absence of heterogeneity for prospective cohort studies (pooled odds ratio 2.77; 95% CI 1.79-4.28; I² = 0%), and studies with HIV-infected patients (pooled odds ratio 7.13; 95% CI 2.83-17.92; I² = 0%).

CONCLUSIONS

We found a significantly higher risk of HCC in patients with CHD. Although further studies are needed to definitively exclude a potential bias due to antiviral treatments, our findings highlight the rationale for improved screening of hepatitis D virus infection in patients with chronic hepatitis B, and the urgent need for novel and effective antiviral therapies.

LAY SUMMARY

Hepatitis D virus (HDV) is a defective pathogen requiring hepatitis B virus (HBV) to complete its life cycle. Chronic hepatitis D is the most severe form of chronic viral hepatitis, increasing the risk of cirrhosis, liver decompensation and death compared to HBV monoinfection. However, the association between HDV infection and increased risk of hepatocellular carcinoma is debated. We conducted a systematic review and found that patients with HDV infection had a significantly higher risk of developing hepatocellular carcinoma than those with HBV monoinfection.

Hepatitis delta genotype 5 is associated with favourable disease outcome and better response to treatment compared to genotype 1

BACKGROUND & AIMS

Coinfection with HDV causes rapid progression to liver cirrhosis and hepatic decompensation in patients with chronic hepatitis B. Factors that are associated with disease progression are poorly understood. In this study we aim to identify risk factors associated with disease progression and better characterise clinical differences and treatment response between HDV genotype 1 and 5.

METHODS

In this retrospective study, all patients under our care between 2005 and 2016 with HBV/HDV coinfection (HBsAg+, anti-HDV antibodies positive) were analysed. Patients were excluded if follow-up was less than 6 months, if they had HCV and/or HIV coinfection or an acute HDV infection. Demographic data, stage of liver disease, development of liver complications and treatment response were recorded.

RESULTS

One-hundred seven patients (mean age 36.0 years, 57% male) were followed for a median period of 4.4 years (range 0.6-28.1 years); 64% were of African origin and 17% were of European origin, with 28% of patients being cirrhotic at first visit; 43% patients had actively replicating HDV virus (anti-HDV-IgG+, anti-HDV-IgM+ or HDV RNA+) and 57% of patients were HDV exposed (anti-HDV-IgG+, HDV RNA-). Patients with actively replicating HDV more often developed liver complications than HDV-exposed patients (p = 0.002), but no differences in baseline characteristics were observed. Patients with HDV genotype 5 less often developed cirrhosis or hepatic decompensation compared to patients with HDV genotype 1. Twenty-four patients were treated with peg-IFN and post-treatment response was significantly better in patients infected with genotype 5 (10% GT1 vs. 64% GT5, p = 0.013).

CONCLUSION

Patients infected with HDV genotype 5 appear to have a better prognosis with fewer episodes of hepatic decompensation and better response to peg-IFN treatment than patients infected with HDV genotype 1.

LAY SUMMARY

Hepatitis delta is a virus that affects the liver. The virus is known to have different subtypes, called genotypes. With this research we discovered that hepatitis delta virus genotype 1 behaves differently than genotype 5 and causes faster development of liver disease. This is important for education of our patients and to determine how often we need to check our patients.

Hepatitis Delta: Prevalence, Natural History, and Treatment Options

Half a century after its discovery, hepatitis delta remains a pertinent global health issue with a major clinical impact in endemic regions and an underestimated prevalence worldwide. Hepatitis delta virus infection follows a challenging clinical course and is responsible for significant liver-related morbidity. Although the only currently available treatment (pegylated interferon) does not provide consistent results, emerging therapeutic options are promising. This article explores the epidemiology, natural history, as well as current and potential therapeutic options for hepatitis delta virus infection.

Peginterferon alfa-2a plus tenofovir disoproxil fumarate for hepatitis D (HIDIT-II): a randomised, placebo controlled, phase 2 trial

BACKGROUND

Hepatitis D is the most severe form of chronic viral hepatitis. Treatment guidelines recommend 1 year of peginterferon alfa, which is effective in 25-30% of patients only. Whether prolonged therapy with peginterferon alfa-2a for 96 weeks and combination therapy with tenofovir disoproxil fumarate (TDF) would increase hepatitis D virus (HDV) RNA suppression is unknown. We aimed to explore whether prolonged treatment of HDV with 96 weeks of peginterferon would increase HDV RNA response rates and reduces post-treatment relapses.

METHODS

We did two parallel, investigator-initiated, multicentre, double-blind randomised, controlled trials at 14 study sites in Germany, Greece, Romania, and Turkey. Patients with chronic HDV infection and compensated liver disease who were aged 18 years or older were eligible for inclusion. All patients were HBsAg positive for at least 7 months, anti-HDV positive for at least 3 months, and HDV-RNA positive at the local laboratory at the screening visit. Patients were ineligible if alanine aminotransferase levels were higher than ten times above the upper limit of normal and if platelet counts were lower than 90 000 per μL, or if they had received interferon therapy or treatment with a nucleoside and nucleotide analogue within the preceding 6 months. Patients were randomly assigned by blinded stratified block randomisation (1:1) to receive 180 μg of peginterferon alfa-2a weekly plus either TDF (300 mg once daily) or placebo for 96 weeks. The primary endpoint was the percentage of patients with undetectable HDV RNA at the end of treatment assessed by intention to treat. The trials are registered as NCT00932971 and NCT01088659.

FINDINGS

Between June 24, 2009, and Feb 28, 2011, we randomly assigned 59 HDV RNA-positive patients to receive peginterferon alfa-2a plus TDF and 61 to receive peginterferon alfa-2a plus placebo, including 48 (40%) patients with cirrhosis to the two treatment groups (23 in the peginterferon alfa-2a plus TDF group and 25 in the peginterferon alfa-2a plus placebo group). The primary endpoint was achieved in 28 (48%) of 59 patients in the peginterferon alfa-2a plus TDF group and in 20 (33%) of 61 patients in the peginterferon alfa-2a plus placebo group (odds ratio 1·84, 95% CI 0·86-3·91, p=0·12). We recorded 944 adverse events (459 in the peginterferon alfa-2a plus TDF group and 485 in the peginterferon alfa-2a plus placebo group). The most common adverse events were haematological, behavioural (eg, fatigue), musculoskeletal, influenza-like syndromes, and psychiatric complaints.

INTERPRETATION

Addition of TDF resulted in no significant improvement in HDV RNA response rates at the end of treatment. These findings highlight that alternative treatment options are needed for hepatitis D.

FUNDING

The HepNet Study-House (a project of the German Liver Foundation founded by the German Liver Foundation, the German Ministry for Education and Research, and the German Center for Infectious Disease Research), Hoffmann-La Roche, and Gilead Sciences.