Perspective on Emerging Therapies to Achieve Functional Cure of Chronic Hepatitis B.

Purpose of Review: Advancements in our understanding of the hepatitis B viral (HBV) life cycle have paved the way for novel approaches to treat HBV infection. This review summarizes the various strategies being pursued to achieve a functional cure, defined as loss of hepatitis B surface antigen (HBsAg) and absence of viral replication 6 months off-therapy. Recent Findings: Direct acting antiviral, host targeting antiviral, and immunological approaches are in various stages of development as treatment for chronic HBV infection. Summary: Novel treatments are being developed in pursuit of a cure for HBV. Current evidence suggests a single therapeutic agent alone may be insufficient, necessitating the need for combination therapy targeting HBV and the host immune response. Ongoing research focused on identifying the best therapeutic combination holds promise in achieving functional cure for HBV.

Hepatitis B Vaccine: Four Decades on.

Hepatitis B virus is a substantial contributor to cirrhosis and hepatocellular carcinoma (HCC) globally. Vaccination is the most effective method for prevention of hepatitis B and its associated morbidity and mortality, and the only method to prevent infection with hepatitis D virus. The hepatitis B vaccine has been used worldwide for more than four decades; it is available in a single- or triple-antigen form and in combination with vaccines against other infections. Introduction of the vaccine and administration at birth led to sustained decline in mother-to-child transmission, chronic hepatitis B, and HCC, however, global birth dose coverage remains suboptimal. In this review we will discuss different hepatitis B vaccine formulations and schedules, vaccination guidelines, durability of the response, and vaccine escape mutants, as well as the clinical and economic benefits of vaccination.

Tools Needed to Support Same-day Diagnosis and Treatment of Current Hepatitis C Infection.

Current HCV prevention efforts and treatment rates must improve for the United States (U.S.) to achieve WHO global elimination targets by 2030[1]. The current multi-day diagnosis and treatment paradigm for hepatitis C (HCV) infection leads to significant loss in the cascade of care, resulting in far fewer patients receiving treatment with direct acting antiviral agents (DAAs) than those diagnosed with HCV infection [2,3]. To achieve HCV elimination, a paradigm shift in access to HCV treatment is needed from current multi-day testing and treatment algorithms to same day diagnosis and treatment. This shift will require new tools, such as FDA-approved, CLIA-waived point-of-care (POC) antigen or nucleic acid tests (NAT) for HCV and HBV and NAT for HIV that do not require venous blood. Such a shift will also require better utilization of existing resources, expanding access to HCV treatment through availability of onsite treatment, removal of payer barriers to approval, adoption of minimal monitoring approaches during treatment, expanded access to available POC tests, and available specialist referral networks for patients who fail initial therapy, have advanced liver fibrosis, or have co-incident HIV or HBV infection. A same-day diagnosis and treatment paradigm will substantially contribute to HCV elimination by improving treatment rates for those diagnosed with HCV infection and expanding access to treatment in settings where patients have brief encounters with healthcare.

Controlled Human Infection Model for Hepatitis C Virus Vaccine Development: Trial Design Considerations.

The design of a clinical trial for a controlled human infection model (CHIM) to accelerate hepatitis C virus (HCV) vaccine development requires careful consideration. The design of a potential approach to HCV CHIM is outlined, involving initial sentinel cohorts to establish the safety and curability of the viral inoculum followed by larger cohorts to establish the spontaneous clearance rate for each inoculum. The primary endpoint would be HCV clearance by 24 weeks post-inoculation, recognizing that the prevention of chronic infection would be the primary goal of HCV vaccine candidates. Additional considerations are discussed, including the populations to be enrolled, the required monitoring approach, indications for antiviral therapy, and the required sample size for different CHIM approaches. Finally, safety considerations for CHIM participants are discussed.

Human immunodeficiency virus coinfection differentially impacts hepatitis B virus viral markers based on hepatitis Be antigen status in patients with suppressed viremia.

Hepatitis B virus (HBV) RNA and hepatitis B core-related antigen (HBcrAg), reflecting transcriptional activity of covalently closed circular DNA, are gaining traction as important markers to assess viral activity. Whether their expression differs under viral suppression by HIV co-infection status is unknown. Among adults with chronic HBV on antiviral therapy, we sought to determine if the expression of HBV markers (specialized and well-established) differs between HBV-HIV co-infection vs. HBV mono-infection. We compared HBV marker levels among 105 participants in the Hepatitis B Research Network (HBRN) HBV-HIV Ancillary Study and 105 participants in the HBRN mono-infected Cohort Study, matched for HBeAg status and HBV DNA suppression on therapy. Among HBeAg+ participants (N = 58 per group), after adjusting for age, sex, race, ALT and HBV DNA, viral markers were higher (p < .05) in the HBV-HIV versus the HBV-only sample (HBeAg: 1.05 vs. 0.51 log10 IU/mL; HBsAg: 3.85 vs. 3.17 log10 IU/mL; HBV RNA: 5.60 vs. 3.70 log10 U/mL; HBcrAg: 6.59 vs. 5.51 log10 U/mL). Conversely, among HBeAg(-) participants (N = 47 per group), HBsAg (2.00 vs. 3.04 log10 IU/mL) and HBV RNA (1.87 vs. 2.66 log10 U/mL) were lower (p < .05) in HBV-HIV vs. HBV-only; HBcrAg levels were similar (4.14 vs. 3.64 log10 U/mL; p = .27). Among adults with chronic HBV with suppressed viremia on antiviral therapy, viral markers tracked with HIV co-infection status and associations differed inversely by HBeAg status. The greater sensitivity and specificity of HBV RNA compared to HBcrAg allows for better discrimination of transcriptional activity regardless of HBeAg status.

Association of Alanine Aminotransferase Flares to Hepatitis B Surface Decline During Tenofovir Alone or With Pegylated Interferon Alfa.

INTRODUCTION: We aimed to determine whether the intensity of alanine aminotransferase (ALT) flares during antiviral therapy is associated with the level of hepatitis B surface antigen (HBsAg) decline. METHODS: Quantitative HBsAg was determined during tenofovir monotherapy or tenofovir plus peginterferon alfa-2a in 201 participants with hepatitis B e antigen-positive or -negative chronic hepatitis B. A multivariable analysis identified factors associated with a shorter time to reduction in HBsAg. RESULTS: Fifty flares occurred during treatment of which 74% were moderate (ALT >5-10 × upper limit of normal) or severe (ALT >10 × upper limit of normal). These flares were associated with greater HBsAg decline compared with no flares. Significantly faster times to HBsAg decline >1 log 10 IU ( P = 0.04) and to HBsAg level <100 IU/mL ( P = 0.01) were observed with severe flares. DISCUSSIONS: Flare severity is a potentially important factor associated with shorter time to HBsAg reduction. These findings can be useful when evaluating HBsAg response to evolving hepatitis B virus therapies.

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 < LLOQ 24 weeks off-treatment. Clinical trials should initially focus on patients with HBeAg positive or negative CHB, who are treatment-naive or virally suppressed on nucleos(t)ide analogs. Hepatitis flares may occur during curative therapy and should be promptly investigated and outcomes reported. HBsAg loss would be the preferred endpoint for chronic hepatitis D, but HDV RNA < LLOQ 24 weeks off-treatment is a suitable alternate primary endpoint of phase II/III trials assessing finite strategies. For trials assessing maintenance therapy, the primary endpoint should be HDV RNA < LLOQ assessed at on-treatment week 48. An alternate endpoint would be ≥2 log reduction in HDV RNA combined with normalization of alanine aminotransferase level. Suitable candidates for phase II/III trials would be treatment-naiive or experienced patients with quantifiable HDV RNA. Novel biomarkers (hepatitis B core-related antigen [HBcrAg] and HBV RNA) remain exploratory, while nucleos(t)ide analogs and pegylated interferon still have a role in combination with novel agents. Importantly, patient input is encouraged early on in drug development under the FDA/EMA patient-focused drug development programs.

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

Safety and yield of percutaneous liver biopsy in adults and children with chronic hepatitis B: Results from a prospective, multicenter study.

BACKGROUND: Prospective data regarding the safety and yield of liver biopsy in both adults and children with chronic hepatitis B are limited. The aim of this study is to report safety, yield, and complication rates among adults and children with chronic hepatitis B undergoing percutaneous liver biopsy. METHODS: Data on the indication for procedural characteristics and complication rate for liver biopsies performed as part of the Hepatitis B Research Network were prospectively recorded on a study case report form and analyzed in aggregate. RESULTS: Among 2506 adult and pediatric subjects enrolled in the Hepatitis B Research Network between 2011 and 2018, 465 (19%) underwent 491 liver biopsies for clinical or research reasons. Adequate liver tissue was obtained in 98% of the procedures. In total, there were 32 complications reported for 24 biopsies: 23 biopsies with 30 complications in adults and 1 biopsy with 2 complications in children. Pain (n=19) and vasovagal reaction (n=6) were the most common complications. There were 7 serious adverse events, including an arterioportal venous fistula, a pneumothorax, 4 cases of bleeding, and severe pain with no associated condition. There were no deaths. CONCLUSIONS: These data demonstrate that percutaneous liver biopsy is associated with a high yield of tissue (98%) and a rate of serious complications of 1.4% in both children and adults with chronic HBV. These results support the focused use of liver biopsy in the evaluation of novel treatments in development for chronic hepatitis B.

Racial Disparities in Treatment Initiation and Outcomes of Chronic Hepatitis B Virus Infection in North America.

Importance: Disparities in treatment initiation may affect outcomes, but data on racially diverse populations with chronic hepatitis B virus (HBV) infection are limited. Objective: To examine whether HBV treatment initiation and outcomes differ among racial groups. Design, Setting, and Participants: From January 14, 2011, to January 28, 2018, hepatitis B surface antigen-positive adults (age ≥18 years) not receiving anti-HBV therapy were enrolled and followed up at weeks 12, 24, and every 24 weeks thereafter in a multicenter longitudinal cohort study (Hepatitis B Research Network [HBRN] adult cohort study) conducted in North America. The last study visit and data collection were completed January 28, 2019. Data were analyzed from August 27, 2021, to August 25, 2022. All HBRN participants were included unless they had acute HBV, HIV, hepatitis C or D, less than 24-weeks of follow-up after enrollment, initiated treatment at or immediately after enrollment, or had unknown race. Exposures: Participants had clinical and laboratory assessments and could receive anti-HBV treatment after enrollment. Main Outcomes and Measures: Hepatitis B virus treatment initiation and major adverse liver outcomes (hepatic decompensation, hepatocellular carcinoma, liver transplant, and death). Results: Of 1550 participants, 193 (12%) were African American or Black, 1157 (75%) were Asian, 157 (10%) were White, and 43 (3%) were other races; 789 (51%) were women, and the median age was 41.2 (IQR, 32.9-51.6) years. Sociodemographic and virologic parameters differed between groups. During 5727 person-years of follow-up, 504 participants initiated treatment, with incidences of 4.8 per 100 person-years in African American or Black individuals, 9.9 per 100 person-years in Asian individuals, 6.6 per 100 person-years in White individuals, and 7.9 per 100 person-years in those of other races (P < .001). A lower proportion (14%) of African American or Black participants met treatment criteria compared with Asian (22%) and White (27%) individuals (P = .01). The cumulative probabilities of treatment initiation after meeting the criteria were not significantly different among racial groups (African American or Black, 0.45; Asian, 0.38; White, 0.40 at 48 weeks and African American or Black, 0.45; Asian, 0.51; White, 0.51 at 72 weeks; P = .68). The incidence of major adverse liver outcomes was 0.1 per 100 person-years and did not differ by race. Conclusions and Relevance: In this observational study of chronic HBV, African American or Black participants were less likely than individuals of other races to meet treatment criteria, but among those who did, HBV treatment receipt did not differ significantly by race or socioeconomic factors. Not all eligible participants initiated treatment, but adverse liver outcomes were rare. These findings may not be generalizable to patients with chronic HBV receiving care in other settings.

Use of HBV RNA and to predict change in serological status and disease activity in CHB.

BACKGROUND AND AIMS: Predicting changes in disease activity and serological endpoints is necessary for the management of patients with chronic hepatitis B (CHB). We examined whether HBV RNA and hepatitis B core-related antigen (HBcrAg), two specialized virological markers proposed to reflect the activity of covalently closed circular DNA, may improve the ability to predict not sustained inactive carrier phase, spontaneous alanine aminotransferase (ALT) flare, HBeAg loss, and HBsAg loss. APPROACH AND RESULTS: Among eligible participants enrolled in the North American Hepatitis B Research Network Adult Cohort Study, we evaluated demographic, clinical, and virologic characteristics, including HBV RNA and HBcrAg, to predict not sustained inactive carrier phase, ALT flare, HBeAg loss, and HBsAg loss through a series of Cox proportional hazard or logistic regression models, controlling for antiviral therapy use. Among the study population, 54/103 participants experienced not sustained inactive carrier phase, 41/1006 had a spontaneous ALT flare, 83/250 lost HBeAg, and 54/1127 lost HBsAg. HBV RNA or HBcrAg were predictive of all 4 events. However, their addition to models of the readily available host (age, sex, race/ethnicity), clinical (ALT, use of antiviral therapy), and viral factors (HBV DNA), which had acceptable-excellent accuracy (e.g., AUC = 0.72 for ALT flare, 0.92 for HBeAg loss, and 0.91 for HBsAg loss), provided only small improvements in predictive ability. CONCLUSION: Given the high predictive ability of readily available markers, HBcrAg and HBV RNA have a limited role in improving the prediction of key serologic and clinical events in patients with CHB.

Low Rate of Hepatitis B Reactivation Among Patients with Chronic Hepatitis C During Direct Acting Antiviral Therapy.

BACKGROUND AND AIMS: Hepatitis B virus (HBV) reactivation has been reported in patients co-infected with hepatitis C virus (HCV) during direct acting antiviral (DAA) therapy, leading the United States Food and Drug Administration (U.S. FDA) to issue a black box warning on all DAA drug labels recommending monitoring for HBV reactivation. We conducted a comprehensive evaluation to assess the rate of HBV reactivation among patients with chronic hepatitis C (CHC) during DAA therapy. METHODS: Patients with CHC and recovered HBV infection (hepatitis B surface antigen negative (HBsAg)/anti-hepatitis B core positive), treated with DAAs were included if stored sera were available. Samples were tested for HBV DNA, HBsAg, and ALT. HBV reactivation was considered if (1) HBV DNA was undetectable pre-DAA therapy and became detectable post-therapy, or (2) HBV DNA was detectable pre-treatment, but not quantifiable (< 20 IU/mL) and became quantifiable post-treatment. RESULT: 79 patients with median age of 62 years were included. 68% were male and Caucasian. Various DAA regimens were administered for 12-24 weeks. Reactivation occurred in 8/79 (10%) of patients and occurred more frequently in men compared to women: 6 during treatment and 2 after treatment. Neither an ALT flare nor HBsAg seroreversion were observed. Detectable HBV DNA was transient in 5/8 and could not be determined in 3/8 but ALT flares were not observed in follow-up of these patients. CONCLUSION: The risk of HBV reactivation was low in CHC patients with resolved HBV during DAA therapy. Our data support testing for HBV DNA only in selected patients with ALT flares or failure of ALT normalization during DAA treatment.

Immunostaining for hepatitis B viral antigens in liver: Association with clinical, biochemical, and virologic features of disease.

BACKGROUND AND AIM: Staining for hepatitis B viral antigens is often done in liver biopsies from patients with chronic hepatitis B, but its correlates with clinical phenotypes are not well described. METHODS: Biopsies were collected from a large cohort of adults and children with chronic hepatitis B viral infection through the Hepatitis B Research Network. Immunohistochemical staining of sections was done for hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg) and then centrally read by the pathology committee. The degree of liver injury and pattern of staining were then correlated with clinical characteristics, including the clinical phenotype of hepatitis B. RESULTS: Biopsies from 467 subjects were studied, including 46 from children. Immunostaining for HBsAg was positive in 417 (90%) with scattered hepatocyte staining being the most common pattern. HBsAg staining correlated best with serum levels of HBsAg and hepatitis B viral DNA; the absence of HBsAg staining was often a prelude to loss of HBsAg from serum. HBcAg staining was positive in 225 (49%), and, while cytoplasmic staining was more frequent than nuclear staining, both nuclear and cytoplasmic positivity were often seen in the same specimen. Staining for HBcAg correlated with both level of viremia and liver injury. No biopsies from inactive carriers had stainable HBcAg, while 91% of the biopsies from those with hepatitis B e antigen-positive chronic hepatitis B stained positively for HBcAg. CONCLUSION: Immunostaining for hepatitis B viral antigens may yield helpful insights into liver disease pathogenesis but appears to add little to commonly used serological and biochemical blood tests.

Patients With Compensated Hepatitis B Virus-Related Cirrhosis and Low-Level Viremia: Treat or Not to Treat?

ABSTRACT: Patients with hepatitis B virus-related cirrhosis and low-level viremia represent a special group that might benefit from treatment because of their higher risk of complications. Evidence for the benefit of treatment in this population is lacking. The current study, which analyzed data of a historical cohort of 627 patients from a single Korean center with hepatitis B virus-related compensated cirrhosis, reported a 2.4-fold increased hepatocellular carcinoma risk among patients with low-level viremia compared with those with undetectable viremia provides indirect evidence in support of treatment for this population. The study underscores the importance of treating patients before the development of cirrhosis and the need for finite duration curative therapy.

Withdrawal of Long-Term Nucleotide Analog Therapy in Chronic Hepatitis B: Outcomes From the Withdrawal Phase of the HBRN Immune Active Treatment Trial.

INTRODUCTION: Withdrawal of nucleos(t)ide analog therapy is increasingly being evaluated in chronic hepatitis B infection as a strategy to induce hepatitis B surface antigen (HBsAg) loss. The Hepatitis B Research Network Immune-Active Trial evaluated treatment with tenofovir (TDF) for 4 years ± an initial 6 months of peginterferon-α (PegIFN) (NCT01369212) after which treatment was withdrawn. METHODS: Eligible participants (hepatitis B e antigen [HBeAg]-/anti-HBe+, hepatitis B virus [HBV] DNA <10 3 IU/mL, no cirrhosis) who discontinued TDF were followed for at least 1 year with optional follow-up thereafter. Retreatment was based on predefined criteria. RESULTS: Among 201 participants who received 4 years of treatment, 97 participants (45 TDF and 52 TDF + PegIFN arm, 79 Asian) discontinued TDF. HBsAg loss occurred in 5 participants, 2 within 25 weeks and 3 within 89-119 weeks postwithdrawal (cumulative rate 4.3% by 2 years). Alanine aminotransferase (ALT) flares (>5× upper limit of normal) after TDF withdrawal occurred in 36 (37.1%) participants and occurred more frequently and earlier in those HBeAg- compared with HBeAg+ at treatment initiation. ALT flares were associated with older age and higher HBV DNA pretreatment and at the visit before the flare. ALT flares were not significantly associated with HBsAg decline or loss but were associated with immune active disease at 1 year (70.6% vs 11.9%, P < 0.0001) and 2 years (66.7% vs 25.9%, P = 0.03) postwithdrawal. Treatment reinitiation was required in 13 (13.4%) participants, and 13 others remained in a sustained inactive carrier state by the end of the study follow-up. No criteria reliably predicted safe treatment withdrawal. DISCUSSION: Results from this trial do not support TDF withdrawal as a therapeutic strategy. HBsAg loss was infrequent within 2 years of stopping long-term TDF. If withdrawal is considered, HBV DNA should be carefully monitored with reinitiation of therapy if levels rise above 4 log 10 IU/mL to reduce the risk of ALT flares, as they were not associated with subsequent HBsAg decline or loss.

Randomized Trial of Tenofovir With or Without Peginterferon Alfa Followed by Protocolized Treatment Withdrawal in Adults With Chronic Hepatitis B.

INTRODUCTION: Hepatitis B surface antigen (HBsAg) loss is associated with improved long-term outcomes of patients with chronic hepatitis B but is infrequently achieved with current monotherapies. We assessed whether combination strategies that included treatment withdrawal enhanced HBsAg loss. METHODS: A randomized (1:1) trial of tenofovir disoproxil fumarate (TDF) for 192 weeks with or without peginterferon (PegIFN) alfa-2a for the first 24 weeks, followed by withdrawal of TDF at week 192 with 48 weeks of off-treatment follow-up to week 240. The primary end point was HBsAg loss at week 240. RESULTS: Of 201 participants (52% HBeAg positive, 12%/6% genotype A/A2, 7% cirrhosis) randomized to TDF + PegIFN (n = 102) or TDF alone (n = 99), 6 participants had lost HBsAg at the end of the treatment phase (week 192), 5 (5.3%) in the combination group, and 1 (1.0%) in the TDF alone group ( P = 0.09). By week 240, 9 participants had cleared HBsAg, 5.3% in combination, and 4.1% in monotherapy arms ( P = 0.73). HBsAg decline and loss occurred earlier with TDF + PegIFN than TDF, with a ≥1-logIU/mL qHBsAg decline by week 24 in 28% in TDF + PegIFN compared with 6% in TDF ( P = 0.04). HBsAg loss occurred in 7 of 12 (58%) with hepatitis B virus subgenotype A2 (all HBeAg positive) compared with only 2 of 189 (1%) with other hepatitis B virus genotypes and in 8 of 93 (8.6%) HBeAg positive vs 1 of 87 (1.1%) HBeAg negative. DISCUSSION: PegIFN combined TDF followed by protocolized TDF withdrawal led to earlier but not higher percentages of HBsAg clearance. Pretreatment HBeAg positivity and subgenotype A2 were strongly associated with HBsAg clearance.

Current Best Practice in Hepatitis B Management and Understanding Long-term Prospects for Cure.

The hepatitis B virus (HBV) is a major cause of cirrhosis and hepatocellular carcinoma worldwide. Despite an effective vaccine, the prevalence of chronic infection remains high. Current therapy is effective at achieving on-treatment, but not off-treatment, viral suppression. Loss of hepatitis B surface antigen, the best surrogate marker of off-treatment viral suppression, is associated with improved clinical outcomes. Unfortunately, this end point is rarely achieved with current therapy because of their lack of effect on covalently closed circular DNA, the template of viral transcription and genome replication. Major advancements in our understanding of HBV virology along with better understanding of immunopathogenesis have led to the development of a multitude of novel therapeutic approaches with the prospect of achieving functional cure (hepatitis B surface antigen loss) and perhaps complete cure (clearance of covalently closed circular DNA and integrated HBV DNA). This review will cover current best practice for managing chronic HBV infection and emerging novel therapies for HBV infection and their prospect for cure.