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

Prognostic value of angiogenic T cells in hepatitis B-induced liver cirrhosis

This study was performed to investigate the frequency of angiogenic T cells (CD4+ Tang cells) among CD4+ T cells in patients with hepatitis B-induced liver cirrhosis (HBV-LC) and to evaluate the predictive role of these cells in the clinical outcome. In total, 185 patients with HBV-LC were recruited to measure the frequency of CD4+ Tang cells and chemokine levels using flow cytometry. RESULTS: There was 11.4% of death after 3-momth follow-up. The AUC for the ability of the frequency of CD4+ Tang cell to predict death was 0.724 (higher than those for the MELD score, FIB-4 score, and Child-Pugh classification). Cox regression analysis revealed an association between the frequency of CD4+ Tang cells and a 3-month survival chance. CONCLUSIONS: The lower frequency of CD4+ T ang cells was correlated with the severity of HBV-LC and may serve as a prognostic predictor.

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.

Results of Response-Guided Therapy with Pegylated Interferon Alpha 2a in Chronic Hepatitis B and D

Pegylated interferon alpha 2a continues to be used for the treatment of chronic hepatitis D. The reported on-treatment virologic response varies between 17 and 47%, with relapses in more than 50% of these patients. No stopping rules have been defined, and the duration of the treatment is not clearly established, but it should be between 48 and 96 weeks. In total, 76 patients with compensated liver disease treated with peg-interferon according to the Romanian National protocol for the treatment of hepatitis D were retrospectively included. The duration of treatment was up to 96 weeks, with the following stopping rules: less than a 2 log HDV RNA decrease by week 24 and less than a 1 log decrease every 6 months afterwards. Six months after stopping the treatment, it can be restarted for unlimited cycles. The inclusion criteria were aged above 18, HBs Ag-positive, HDV RNA detectable, ALT above ULN and/or liver fibrosis at least F1 at liver biopsy, or Fibrotest and/or Fibroscan higher than 7 KPa and/or inflammation at least A1 at liver biopsy or Fibrotest. We monitored our patients for a total period of 4 years (including those that repeated the cycle). After the first 6 months of treatment, 27 patients (35.5%) had a greater than 2 log HDV RNA decrease, 19 of them achieving undetectable HDV RNA. Seventeen patients (22.3%) had undetectable HDV RNA 24 weeks after stopping 96 weeks of treatment, and none relapsed in the following 2 years. Of these 17 patients, 6 were cirrhotic, and 4 had F3. Undetectable HDV RNA at 24 weeks was the only parameter that predicted a long-term suppression of HDV RNA. In 49 patients, the treatment was stopped after 6 months according to protocol, but it was restarted 6 months later. Five of these patients finished a 48-week course of treatment; none achieved undetectable HDV RNA. During the first course of therapy, 45 patients had at least one moderate adverse reaction to treatment. In one patient, the treatment was stopped due to a serious adverse event (osteomyelitis). Treatment doses had to be reduced in 29 patients. The virologic response at week 24 can select the patients who will benefit from continuing the treatment from those who should be changed to another type of medication when available.

Management of autoimmune hepatitis induced by hepatitis delta virus

Approximately 12-72 million people worldwide are co-infected with hepatitis B virus (HBV) and hepatitis delta virus (HDV). This concurrent infection can lead to several severe outcomes with hepatic disease, such as cirrhosis, fulminant hepatitis, and hepatocellular carcinoma, being the most common. Over the past few decades, a correlation between viral hepatitis and autoimmune diseases has been reported. Furthermore, autoantibodies have been detected in the serum of patients co-infected with HBV/HDV, and autoimmune features have been reported. However, to date, very few cases of clinically significant autoimmune hepatitis (AIH) have been reported in patients with HDV infection, mainly in those who have received treatment with pegylated interferon. Interestingly, there are some patients with HBV infection and AIH in whom HDV infection is unearthed after receiving treatment with immunosuppressants. Consequently, several questions remain unanswered with the challenge to distinguish whether it is autoimmune or "autoimmune-like" hepatitis being the most crucial. Second, it remains uncertain whether autoimmunity is induced by HBV or delta virus. Finally, we investigated whether the cause of AIH lies in the previous treatment of HDV with pegylated interferon. These pressing issues should be elucidated to clarify whether new antiviral treatments for HDV, such as Bulevirtide or immu-nosuppressive drugs, are more appropriate for the management of patients with HDV and AIH.

The cascade of care for patients with chronic hepatitis delta in Southern Stockholm, Sweden for the past 30 years

BACKGROUND AND AIMS

Previous studies have shown suboptimal screening for hepatitis D virus (HDV) among patients with chronic hepatitis B (CHB). This study presents the cascade of care for HDV infection in a major secondary referral centre in Southern Stockholm, Sweden.

METHODS

HBsAg+ve patients attending Karolinska University Hospital (KUH) from 1992 to 2022 were identified. The prevalence of anti-HDV and/or HDV RNA positivity, interferon (IFN) therapy and maintained virological responses (MVR) after HDV treatment were assessed. Also, time to anti-HDV testing was analysed in relation to liver-related outcomes with logistic regression.

RESULTS

Among 4095 HBsAg+ve persons, 3703 (90.4%) underwent an anti-HDV screening; within a median of 1.8 months (range 0.0-57.1) after CHB diagnosis. This screening rate increased over time, to 97.9% in the last decade. Overall, 310 (8.4%) were anti-HDV+ve, of which 202 (65.2%) were HDV RNA+ve. Eighty-five (42%) received IFN, and 9 (10.6%) achieved MVR at the last follow-up. The predictive factors for anti-HDV screening were Asian origin, diagnosis after the year 2012, HIV co-infection (negative factor) and HBV DNA level < 2000 IU/mL in univariable analysis, while HIV co-infection was the only remaining factor in multivariable analysis. Delayed anti-HDV test >5 years was independently associated with worsened liver-related outcomes (adjusted odds ratio = 7.6, 95% CI 1.8-31.6).

CONCLUSION

Higher frequency of HDV screening than previously published data could be seen among CHB patients at KUH in a low-endemic setting. Receiving a delayed screening test seems to be associated with worse outcomes, stressing the need of a strategy for timely HDV diagnosis.

Five-year follow-up of 96 weeks peginterferon plus tenofovir disoproxil fumarate in hepatitis D

BACKGROUND & AIMS

Until recently, pegylated interferon-alfa-2a (PEG-IFNa) therapy was the only treatment option for patients infected with hepatitis D virus (HDV). Treatment with PEG-IFNa with or without tenofovir disoproxil fumarate (TDF) for 96 weeks resulted in HDV RNA suppression in 44% of patients at the end of therapy but did not prevent short-term relapses within 24 weeks. The virological and clinical long-term effects after prolonged PEG-IFNa-based treatment of hepatitis D are unknown.

METHODS

In the HIDIT-II study patients (including 40% with liver cirrhosis) received 180 μg PEG-IFNa weekly plus 300 mg TDF once daily (n = 59) or 180 μg PEG-IFNa weekly plus placebo (n = 61) for 96 weeks. Patients were followed until week 356 (5 years after end of therapy).

RESULTS

Until the end of follow-up, 16 (13%) patients developed liver-related complications (PEG-IFNa + TDF, n = 5 vs PEG-IFNa + placebo, n = 11; p = .179). Achieving HDV suppression at week 96 was associated with decreased long-term risk for the development of hepatocellular carcinoma (p = .04) and hepatic decompensation (p = .009). Including complications irrespective of PEG-IFNa retreatment status, the number of patients developing serious complications was similar with (3/18) and without retreatment with PEG-IFNa (16/102, p > .999) but was associated with a higher chance of HDV-RNA suppression (p = .024, odds ratio 3.9 [1.3-12]).

CONCLUSIONS

Liver-related clinical events were infrequent and occurred less frequently in patients with virological responses to PEG-IFNa treatment. PEG-IFNa treatment should be recommended to HDV-infected patients until alternative therapies become available. Retreatment with PEG-IFNa should be considered for patients with inadequate response to the first course of treatment.

CLINICAL TRIAL REGISTRATION

NCT00932971.

Impact of hepatitis D reflex testing on the future disease burden: A modelling analysis

Chronic hepatitis D (CHD) is a severe form of viral hepatitis that leads to liver cirrhosis and hepatocellular carcinoma. CHD is underdiagnosed, and this study aimed to assess the impact of hepatitis D reflex testing in HBsAg-positive individuals in Spain over the next 8 years. Two scenarios were compared: the current situation (7.6% of HBsAg-positive patients tested for anti-HDV) and reflex testing for all positive samples. A decision tree model was designed to simulate the CHD care cascade. Implementing reflex testing would increase anti-HDV detection to 5498 cases and HDV-RNA to 3225 cases. Additionally, 2128 more patients would receive treatment, with 213 achieving undetectable HDV-RNA levels. The cost per anti-HDV case detected would be €132. In the median time of the analysis, liver complications (decompensated cirrhosis, HCC and liver-related deaths) would be reduced by 35%-38%, implying an estimated cost savings of 36 million euros associated with the management of such complications. By 2030, implementing anti-HDV reflex testing would reduce the clinical and economic burden of CHD by 35%-38%.

Guidance on treatment endpoints and study design for clinical trials aiming to achieve cure in chronic hepatitis B and D: Report from the 2022 AASLD-EASL HBV-HDV Treatment Endpoints Conference

Representatives from academia, industry, regulatory agencies, and patient advocacy groups convened under the American Association for the Study of Liver Diseases (AASLD) and the European Association for the Study of the Liver (EASL) in June 2022 with the primary goal of achieving consensus on chronic HBV and HDV treatment endpoints to guide clinical trials aiming to "cure" HBV and HDV. Conference participants reached an agreement on some key points. The preferred primary endpoint for phase II/III trials evaluating finite treatments for chronic hepatitis B (CHB) is a "functional" cure, defined as sustained HBsAg loss and HBV DNA less than the lower limit of quantitation (LLOQ) 24 weeks off-treatment. An alternate endpoint would be "partial cure" defined as sustained HBsAg level <100 IU/mL and HBV DNA Collapse

Key Words

• HBV
• HDV
• diagnosis

Collapse

MESH Headings Collapse

Grants

• 001 World Health Organization

Collapse

Affiliation(s)

Marc G Ghany Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA.
Maria Buti Liver Unit, Vall d'Hebron University Hospital and CIBEREHD del Instituto Carlos III, Barcelona, Spain
Pietro Lampertico Division of Gastroenterology and Hepatology, Milan, Italy; CRC "A. M. and A. Migliavacca" Center for Liver Disease, Milan, Italy
Hannah M Lee Department of Gastroenterology, Hepatology and Nutrition, Stravitz Sanyal Institute for Liver Disease and Metabolic Health, Virginia Commonwealth University, Richmond, Virginia, USA

Collapse

Comparative effectiveness of seven interventions for chronic hepatitis D: a systematic review and network meta-analysis of randomized controlled trials

OBJECTIVE

To compare the effectiveness of seven major interventions [Bulevirtide (BLV), Interferon (IFN), Nucleoside analogs (NAs), BLV + IFN, BLV + NAs, IFN + NAs, and Placebo] to treat chronic hepatitis D.

METHODS

We followed PRISMA-NMA guidelines, searched databases (Cochrane Library, PubMed, EMBASE, and Web Of Science) for eligible randomized controlled trials (RCTs), and applied STATA17.0 software to execute the meta-analysis.

RESULTS

We included 14 randomized controlled trials (814 patients) comparing seven different interventions. The results of the network meta-analysis showed that: ① Sustained virological response (after 24 weeks of follow-up): Four intervention groups (BLV + IFN, IFN alone, IFN + NAs, and NAs alone) were effective (relative risk (RR) = 13.30, 95% confidence interval (Cl) [1.68,105.32], RR = 12.13, 95% Cl [1.46,101.04], RR = 5.05, 95% Cl [1.68,15.19], RR = 5.03, 95% Cl [1.66,15.20]), with no statistically significant differences between the four groups. The top three in probability rankings were: BLV + NAs, BLV + IFN, and BLV alone (surface under the cumulative ranking curve (SUCRA) = 86.8%, 80.3%, and 48.4%; ② Sustained biochemical response (after 24 weeks of follow-up): BLV + IFN and IFN were superior to BLV (RR = 14.71, 95% Cl [1.14,189.07], RR = 16.67, 95% Cl [1.39,199.52]). The top three were BLV alone, BLV + NAs, and BLV + IFN (SUCRA = 86.9%,81.2%, and 64.3%). ③ Histological response: NAs were superior to BLV (RR = 2.08, 95% Cl [1.10,3.93]), whereas the difference between other treatment regimens was not statistically significant, and the top three in the probability ranking were BLV alone, BLV + NAs, and BLV + IFN (SUCRA = 75.6%, 75.6%, and 61.8%).

CONCLUSIONS

IFN, IFN + BLV, and IFN + NAs were effective in clearing HDV RNA and normalizing alanine aminotransferase levels; however, IFN and IFN + NAs had a high rate of viral relapse at 24 weeks post-treatment follow-up. There was no additional benefit of adding NAs to IFN therapy for chronic hepatitis D; however, the combination of IFN + BLV significantly improved short-term HDV RNA clearance, which showed strong synergistic effects. The seven regimens included in the study did not contribute significantly to liver histological improvement. Therefore, the IFN + BLV combination has the most potential as a treatment option to improve the long-term prognosis or even cure chronic hepatitis D.

TRIAL REGISTRATION

This systematic evaluation and meta-analysis was registered with PROSPERO under the registration number: CRD42022314544.).

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.

Interferon-based treatment of chronic hepatitis D

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

Diagnosis and Management of Hepatitis Delta Virus Infection

Hepatitis D virus (HDV) depends on hepatitis B virus (HBV) to enter and exit hepatocytes and to replicate. Despite this dependency, HDV can cause severe liver disease. HDV accelerates liver fibrosis, increases the risk of hepatocellular carcinoma, and hastens hepatic decompensation compared to chronic HBV monoinfection. The Chronic Liver Disease Foundation (CLDF) formed an expert panel to publish updated guidelines on the testing, diagnosis, and management of hepatitis delta virus. The panel group performed network data review on the transmission, epidemiology, natural history, and disease sequelae of acute and chronic HDV infection. Based on current available evidence, we provide recommendations for screening, testing, diagnosis, and treatment of hepatitis D infection and review upcoming novel agents that may expand treatment options. The CLDF recommends universal HDV screening for all patients who are Hepatitis B surface antigen-positive. Initial screening should be with an assay to detect antibodies generated against HDV (anti-HDV). Patients who are positive for anti-HDV IgG antibodies should then undergo quantitative HDV RNA testing. We also provide an algorithm that describes CLDF recommendations on the screening, diagnosis, testing, and initial management of Hepatitis D infection.

Treatment endpoints for chronic hepatitis D

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

EASL Clinical Practice Guidelines on hepatitis delta virus

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

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.

Chronic hepatitis delta cirrhosis cured by adapting PEG-IFNα-2a + tenofovir disoproxil fumarate treatment duration until HBsAg loss

As the loss of HBsAg during treatment of chronic hepatitis delta (CHD) is mandatory for definitive clearance and durable response, the optimal target of therapy should be complete response (CR), defined as loss of HDV RNA and HBsAg, plus development of anti-HBs. The optimal treatment duration of CHD is not well established. We present 2 cases of patients with CHD cirrhosis who were treated with prolonged Peg-IFNα-2a + tenofovir disoproxil fumarate until HBsAg loss, and who achieved CR after 46 and 55 months of treatment respectively. A personalized approach and prolonged treatment duration determined by HBsAg loss may increase the likelihood of CR in CHD.

A Phase 3, Randomized Trial of Bulevirtide in Chronic Hepatitis D

BACKGROUND

Coinfection with hepatitis D virus (HDV) accelerates the progression of liver disease associated with chronic hepatitis B. Bulevirtide inhibits the entry of HDV into hepatocytes.

METHODS

In this ongoing phase 3 trial, patients with chronic hepatitis D, with or without compensated cirrhosis, were randomly assigned, in a 1:1:1 ratio, to receive bulevirtide subcutaneously at 2 mg per day (2-mg group) or 10 mg per day (10-mg group) for 144 weeks or to receive no treatment for 48 weeks followed by bulevirtide subcutaneously at 10 mg per day for 96 weeks (control group). Patients will complete 96 weeks of additional follow-up after the end of treatment. The primary end point was a combined response at week 48 of an undetectable HDV RNA level, or a level that decreased by at least 2 log10 IU per milliliter from baseline, and normalization of the alanine aminotransferase (ALT) level. The key secondary end point was an undetectable HDV RNA level at week 48, in a comparison between the 2-mg group and the 10-mg group.

RESULTS

A total of 49 patients were assigned to the 2-mg group, 50 to the 10-mg group, and 51 to the control group. A primary end-point response occurred in 45% of patients in the 2-mg group, 48% in the 10-mg group, and 2% in the control group (P<0.001 for the comparison of each dose group with the control group). The HDV RNA level at week 48 was undetectable in 12% of patients in the 2-mg group and in 20% in the 10-mg group (P = 0.41). The ALT level normalized in 12% of patients in the control group, 51% in the 2-mg group (difference from control, 39 percentage points [95% confidence interval {CI}, 20 to 56]), and 56% in the 10-mg group (difference from control, 44 percentage points [95% CI, 26 to 60]). Loss of hepatitis B virus surface antigen (HBsAg) or an HBsAg level that decreased by at least 1 log10 IU per milliliter did not occur in the bulevirtide groups by week 48. Headache, pruritus, fatigue, eosinophilia, injection-site reactions, upper abdominal pain, arthralgia, and asthenia were more common in the 2-mg and 10-mg groups combined than in the control group. No treatment-related serious adverse events occurred. Dose-dependent increases in bile acid levels were noted in the 2-mg and 10-mg groups.

CONCLUSIONS

After 48 weeks of bulevirtide treatment, HDV RNA and ALT levels were reduced in patients with chronic hepatitis D. (Funded by Gilead Sciences; MYR 301 ClinicalTrials.gov number, NCT03852719.).

Emerging drugs for hepatitis D

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Treating hepatitis D with bulevirtide - Real-world experience from 114 patients

Background & Aims

Bulevirtide is a first-in-class entry inhibitor of hepatitis B surface antigen. In July 2020, bulevirtide was conditionally approved for the treatment of hepatitis D, the most severe form of viral hepatitis, which frequently causes end-stage liver disease and hepatocellular carcinoma. Herein, we report the first data from a large multicenter real-world cohort of patients with hepatitis D treated with bulevirtide at a daily dose of 2 mg without additional interferon.

Methods

In a joint effort with 16 hepatological centers, we collected anonymized retrospective data from patients treated with bulevirtide for chronic hepatitis D.

Results

Our analysis is based on data from 114 patients, including 59 (52%) with cirrhosis, receiving a total of 4,289 weeks of bulevirtide treatment. A virologic response defined as an HDV RNA decline of at least 2 log or undetectable HDV RNA was observed in 87/114 (76%) cases with a mean time to virologic response of 23 weeks. In 11 cases, a virologic breakthrough (>1 log-increase in HDV RNA after virologic response) was observed. After 24 weeks of treatment, 19/33 patients (58%) had a virologic response, while three patients (9%) did not achieve a 1 log HDV RNA decline. No patient lost hepatitis B surface antigen. Alanine aminotransferase levels improved even in patients not achieving a virologic response, including five patients who had decompensated cirrhosis at the start of treatment. Treatment was well tolerated and there were no reports of drug-related serious adverse events.

Conclusions

In conclusion, we confirm the safety and efficacy of bulevirtide monotherapy in a large real-world cohort of patients with hepatitis D treated in Germany. Future studies need to explore the long-term benefits and optimal duration of bulevirtide treatment.

Impact and implications

Clinical trials proved the efficacy of bulevirtide for chronic hepatitis D and led to conditional approval by the European Medical Agency. Now it is of great interest to investigate the effects of bulevirtide treatment in a real-world setting. In this work, we included data from 114 patients with chronic hepatitis D who were treated with bulevirtide at 16 German centers. A virologic response was seen in 87/114 cases. After 24 weeks of treatment, only a small proportion of patients did not respond to treatment. At the same time, signs of liver inflammation improved. This observation was independent from changes in hepatitis D viral load. The treatment was generally well tolerated. In the future, it will be of interest to investigate the long-term effects of this new treatment.

Epidemiology, presentation, and therapeutic approaches for hepatitis D infections

INTRODUCTION

Chronic Hepatitis D virus (HDV) infection remains an important global public health problem, with a changing epidemiological landscape over the past decade along with widespread implementation of hepatitis B vaccination and human migration. The landscape of HDV treatments has been changing, with therapies that have been under development for the last decade now in late stage clinical trials. The anticipated availability of these new therapies will hopefully replace the current therapies which are minimally effective.

AREAS COVERED

This narrative review discusses the clinical course, screening and diagnosis, transmission risk factors, epidemiology, current and investigational therapies, and liver transplantation in HDV. Literature review was performed using PubMed and ClinicalTrials.gov and includes relevant articles from 1977 to 2022.

EXPERT OPINION

HDV infection is an important global public health issue with a true prevalence that is still unknown. The distribution of HDV infection has changed globally with the availability of HBV vaccination and patterns of human migration. As HDV infection is associated with accelerated disease courses and poor outcomes, the global community needs to agree upon a uniform HDV screening strategy to understand the truth of global prevalence such that new therapies can target appropriate individuals as they become available in the future.

Prevalence of HDV infection in people living with HIV: Data from a multicenter Italian cohort

Objectives

The development of novel antiviral agents active against Hepatitis Delta Virus (HDV) might change the natural history of chronic infection, reducing the risk for end-stage liver disease. People living with HIV (PWH) are at risk for bloodborne pathogens infection, but limited data on epidemiology of HDV infection is available in this setting. The aim of this study was to investigate HDV prevalence and attitude toward HDV testing and treatment in infectious diseases centers.

Methods

A cross sectional survey was performed among centers participating in the CISAI (Coordinamento Italiano per lo Studio dell'Allergia in Infezione da HIV) Group. The survey addressed anti-HDV prevalence and HDV-RNA detectability rates in PWH as well as perceived obstacles to treatment.

Results

Overall, responses from ten sites were collected. Among participating centers, 316 PWH with HBV chronic infection are currently followed. Of them, 15.2% had positive anti-HDV antibodies, while 13.9% were not tested yet. Overall, 17% of anti-HDV positive PWH tested at least once for HDV-RNA had active HDV infection, and 71% of them had advanced liver disease. Most infectious diseases centers intend to treat locally HDV infection with upcoming anti-HDV drugs, but some concerns exist regarding treatment schedule.

Discussion

HDV testing needs to be implemented in PWH. At present, few patients followed in the CISAI centers seem to be candidate to receive new direct active anti-HDV agents, but repeated HDV-RNA measures could change this proportion.

Bulevirtide in the Treatment of Hepatitis Delta: Drug Discovery, Clinical Development and Place in Therapy

It has been ten years since the identification of NTCP as the cell surface receptor for HBV and HDV entry into hepatocytes. The search for molecules interfering with the binding of NTCP and HBV/HDV led to design bulevirtide (BLV). This large polypeptide mimics a region of the pre-S1 HBsAg and blocks viral entry by inhibitory competition. BLV was initially tested in cell cultures, animal models and more recently in Phase I-III human trials (called 'MYRS'). As monotherapy or in combination with peginterferon, BLV is well tolerated and exhibits potent antiviral activity. Plasma viremia significantly declines and/or becomes undetectable in more than 75% of patients treated for >24 weeks. However, serum HBsAg concentrations remain unchanged. No selection of BLV resistance in HBV/HDV has been reported in vivo to date. BLV is administered subcutaneously once daily at doses between 2 and 10 mg. BLV received conditional approval in Europe in 2020 to treat chronic hepatitis delta. The advent of peginterferon lambda or new specific anti-HDV antivirals (lonafarnib, etc.) will open the door for combination therapies with BLV. Since there is no stable reservoir for HDV-RNA within infected hepatocytes, viral clearance might be achieved using antivirals for a minimum timeframe. This is what happens in hepatitis C combining several antivirals, curing nearly all patients treated for 3 months. Clearance of HDV-RNA genomes may occur despite HBV persistence as cccDNA or chromosome integrated HBV-DNA within hepatocytes. This is supported by cases of HDV elimination using BLV despite persistence of serum HBsAg. Another path for HDV cure will derive from achieving HBsAg clearance, the goal of new promising anti-HBV gene therapies (bepirovirsen, etc.). In summary, the advent of BLV has triggered a renovated interest for antiviral therapy in hepatitis delta. We envision combination therapies that will lead to HDV cure in the near future.

Non-invasive fibrosis markers for assessment of liver fibrosis in chronic hepatitis delta

Assessment of liver fibrosis by non-invasive means is clinically important. Studies in chronic hepatitis delta (CHD) are scarce. We evaluated the performance of eight serum fibrosis markers [fibrosis-4 score (FIB-4), aspartate aminotransferase (AST) to alanine aminotransferase (ALT) ratio (AAR), age-platelet index (API), AST-to platelet-ratio-index (APRI), Goteborg University Cirrhosis Index (GUCI), Lok index, cirrhosis discriminant score (CDS) and Hui score] in CHD and chronic hepatitis B (CHB). Liver stiffness was assessed by transient elastography (TE) in CHD. The ability of fibrosis markers to detect significant fibrosis and cirrhosis were evaluated in 202 CHB and 108 CHD patients using published and new cut-offs through receiver operating characteristics (ROC) analysis. The latter was also applied to obtain cut-offs for TE. APRI, Fib-4, API and Hui score were assessed for significant fibrosis, and APRI, GUCI, Lok index, CDS and AAR for cirrhosis determination. Fibrosis markers displayed weak performance in CHB for significant fibrosis with area under ROC (AUROC) curves between 0.62 and 0.71. They did slightly better for CHD. TE displayed an AUROC of 0.92 and performed better than serum fibrosis markers (p < 0.05 for fibrosis markers). For cirrhosis determination, CDS and Lok Index displayed an AUROC of 088 and 0.89 in CHB and GUCI, Lok index and APRI displayed AUROCs around 0.90 in CHD. TE displayed the best AUROC (0.95). Hence TE is superior to serum fibrosis markers for diagnosing significant liver fibrosis and cirrhosis. GUCI, Lok index and APRI displayed a reasonable performance in CHD, which needs further confirmation.

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

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

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.

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.

Novel Pegylated Interferon for the Treatment of Chronic Viral Hepatitis

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

Management of Delta Hepatitis 45 Years after the Discovery of HDV

In 1977 the viral Delta agent was discovered and subsequently characterized as the hepatitis Delta virus (HDV). HDV infection is associated with HBV infection since the defective HDV needs HBV to infect and replicate in the liver. Even if not a frequent cause of chronic liver disease, HDV infection is responsible for an aggressive progression of hepatitis towards advanced liver disease. At present, no FDA approved treatment exists for this specific form of hepatitis. Interferon alfa has been recommended as off-label therapy by major scientific societies (AASLD, EASL and APASL) and has proved effective in about one quarter of patients. In recent years, new therapeutic approaches have been studied, and EMA has approved a new drug (bulevirtide) for Delta hepatitis. In this review, we encompass the 45-year journey of managing Delta hepatitis and address the most recent developments in treating this severe and aggressive liver disease.

Viral hepatitis: Innovations and expectations

Viral hepatitis is a significant health problem worldwide, associated with morbidity and mortality. Hepatitis B, C, D, and occasionally E viruses (HBV, HCV, HDV, and HEV) can evolve in chronic infections, whereas hepatitis A virus (HAV) frequently produces acute self-limiting hepatitis. In the last years, different studies have been performed to introduce new antiviral therapies. The most important goal in the treatment of viral hepatitis is to avoid chronic liver disease and complications. This review analyzes currently available therapies, in particular for viruses associated with chronic liver disease. The focus is especially on HBV and HCV therapies, investigating new drugs already introduced in clinical practice and clinical trials. We also describe new entry inhibitors, developed for the treatment of chronic HDV and HBV and currently available treatments for HEV. The last drugs introduced have shown important efficacy in HCV, with achievable target HCV elimination by 2030. Concurrently, renewed interest in curative HBV therapies has been registered; current nucleotide/ nucleoside analogs positively impact liver-related complications, ensuring high safety and tolerability. Novel approaches to HBV cure are based on new antivirals, targeting different steps of the HBV life cycle and immune modulators. The improved knowledge of the HDV life cycle has facilitated the development of some direct-acting agents, as bulevirtide, the first drug conditionally approved in Europe for HDV associated compensated liver disease. Further studies are required to identify a new therapeutic approach in hepatitis E, especially in immunosuppressed patients.

Inhibitory Effect of IL-1β on HBV and HDV Replication and HBs Antigen-Dependent Modulation of Its Secretion by Macrophages

Co-infection with the hepatitis B virus and hepatitis delta virus (HDV) leads to the most aggressive form of viral hepatitis. Using in vitro infection models, we confirmed that IL-1β, a crucial innate immune molecule for pathogen control, was very potent against HBV from different genotypes. Additionally, we demonstrated for the first time a strong and rapid antiviral effect induced by very low doses of IL-1β against HDV. In parallel, using co-culture assays, we demonstrated that monocytes exposed to HBV, and in particular to HBsAg, during differentiation into pro-inflammatory macrophages secreted less IL-1β. Altogether, our data emphasize the importance of developing combined antiviral strategies that would, for instance, reduce the secretion of HBsAg and stimulate the immune system to produce endogenous IL-1β efficient against both HBV and HDV.

Prognostic Value of Serum Exosomal AHCY Expression in Hepatitis B-Induced Liver Cirrhosis

Objective: We aimed to investigate serum exosomal adenosylhomocysteinase (AHCY) expression in hepatitis B-induced liver cirrhosis (HBV-LC) patients and to determine the prognostic value of serum exosomal AHCY. Methods: We collected serum samples from 100 patients with chronic hepatitis B (CHB) and from 114 HBV-LC patients to test serum exosomal AHCY expression using ELISA. Results: Compared with the CHB and Grade A and B HBV-LC groups, the level of exosomal AHCY expression was significantly higher in the HBV-LC group [376.62 (291.50-448.02) vs. 248.12 (189.28-324.63), P > 0.001] and the Grade C HBV-LC group [408.70 (365.63-465.76) vs. 279.76 (215.16-336.07), P > 0.001], respectively. Serum exosomal AHCY expression and MELD score had a significant positive correlation (r = 0.844, P < 0.001). Survival curve analysis showed that patients with low exosomal AHCY expression had significantly longer survival than patients with high exosomal AHCY expression (P = 0.0038). The receiver operating characteristics (ROC) curve showed that the area under the curve (AUC) value for the mortality prediction ability of serum exosomal AHCY in HBV-LC patients was 0.921, which was higher than the values for the MELD score (AUC 0.815) and Child-Pugh classification (AUC 0.832), with a sensitivity and specificity of 93.41 and 76.00%, respectively. Conclusions: The serum exosomal AHCY level is a novel potential prognostic biomarker in HBV-LC patients, which may be great significance for the prognosis of HBV-LC patients.

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

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

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.

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.

Human hepatitis D virus-specific T cell epitopes

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

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

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