Hepatitis B reactivation (HBVr) can occur due to a variety of immune-modulating exposures, including multiple drug classes and disease states. Antiviral prophylaxis can be effective in mitigating the risk of HBVr. In select cases, clinical monitoring without antiviral prophylaxis is sufficient for managing the risk of HBVr. This clinical practice guideline update aims to inform frontline health care practitioners by providing evidence-based practice recommendation for the management of HBVr in at-risk individuals.

The Grading of Recommendations Assessment, Development and Evaluation framework was used to assess evidence and make recommendations. The panel conducted a systematic evidence review to identify new studies since publication of the first version of this clinical practice guideline in 2014. The Evidence to Decision framework was used to develop recommendations regarding the role of antiviral prophylaxis and monitoring without antiviral prophylaxis for management of HBVr. Clinical recommendations were based on the balance between desirable and undesirable effects, patient values, costs, and health equity considerations.

The panel agreed on 4 recommendations. Based on evidence and baseline risk assessment, the panel made a strong recommendation in favor of antiviral prophylaxis for individuals at high risk of HBVr. For individuals at moderate risk of HBVr, a conditional recommendation was made in favor of antiviral prophylaxis. For individuals at low risk of HBVr, a conditional recommendation was made in favor of monitoring alone without antiviral prophylaxis. Monitoring should be performed at 1- to 3-month intervals, and must include assessment of hepatitis B viral load in addition to assessment of alanine aminotransferase. For individuals deemed to be at-risk of HBVr, the panel agreed on a strong recommendation in favor of testing for HBV; given universal Centers for Disease Control and Prevention screening guidance for hepatitis B for all adults 18 years and older by testing for HBV surface antigen, hepatitis B surface antibody, and total hepatitis B core antibody, stratifying screening practices by magnitude of HBVr risk is no longer needed.

This document provides updated guidance for the management of HBVr in at-risk individuals. Limitations and gaps in the evidence are highlighted. This guideline is expected to require updating in 5 years from publication.

Currently, hepatitis B virus (HBV) core antibody (anti-HBc antibody) and HBV core-related antigen (HBcrAg) are widely used as serum markers for diagnosis based on the HBV core region. This review focused on anti-HBc antibodies and HBcrAg and aimed to summarize the clinical significance of currently used assay systems and the issues involved. While anti-HBc is very significant for clinical diagnosis, the clinical significance of quantitative assay of anti-HBc antibody has been reevaluated with improvements in diagnostic performance, including its association with clinical stage and prediction of carcinogenesis and reactivation. In addition, concerning the new HBcrAg, a high-sensitivity assay method has recently been established, and its diagnostic significance, including the prediction of reactivation, is being reevaluated. On the other hand, the quantitative level of anti-HBc antibody expressed in different units among assay systems complicates the interpretation of the results. However, it is difficult to standardize assay systems as they vary in advantages, and caution is needed in interpreting the assay results. In conclusion, with the development of highly sensitive HBcrAg and anti-HBc antibody, a rapid and sensitive detection assay system has been developed and used in clinical practice. In the future, it is hoped that a global standard will be created based on the many clinical findings.

Immune-mediated hepatotoxicity (IMH) is not-so-rare complication during treatment with immune checkpoint inhibitors (ICIs). This narrative review aims to report the current knowledge on hepatic immune-related adverse events (irAEs) during immunotherapy from pathogenesis to multidisciplinary management. The majority of cases of IMH are asymptomatic and only a few patients may have clinical conditions. The severity of IMH is usually stratified according to Common Terminology for Clinical Adverse Events (CTCAE) criteria, but these scores may overestimate the clinical severity of IMH compared to the Drug-Induced Liver Injury Network (DILIN) scale. The differential diagnosis of IMH is challenging because the elevated liver enzymes can be due to a number of etiologies such as viral infection, autoimmune and metabolic diseases, liver metastases, biliary diseases, and other drugs. The cornerstones of IMH management are represented by withholding or delaying ICI administration and starting immunosuppressive therapy. A multidisciplinary team, including oncologists, hepatologists, internists, and emergency medicine physicians, is essential for the management of IMH.

Immunotherapy shows promise as a treatment option for various cancers. However, there is growing concern over potential complications from hepatitis B virus (HBV) reactivation after checkpoint blockade immunotherapy. Although most of the previous clinical trials on immune checkpoint inhibitors (ICIs) excluded patients with HBV, a few case reports and retrospective studies of HBV reactivation have been published. The aim of this study is to assess the risk of hepatitis B virus reactivation (HBVr) in patients receiving ICIs for advanced cancer.

English and Chinese language literature published prior to April 30, 2023, was searched in PubMed, EMBASE, Web of Science, Cochrane, SinoMed, CNKI and Wanfang Data for studies reporting HBVr rates in cancer patients treated with ICIs. A pooled risk estimate was calculated for HBVr rates with 95% confidence intervals (CI).

Data from 34 studies including 7126 patients were retrieved and analyzed. The pooled HBVr rate in cancer patients treated with ICIs was 1.3% (I2 = 90.44%, 95% CI: 0.2-2.9%, P < 0.001). Subgroup analysis revealed that patients diagnosed with hepatocellular carcinoma (HCC), HBV carriers, and patients from Asian regions or in developing countries have a higher rate of HBVr.

Our meta-analysis demonstrated a low risk of HBVr in patients treated with ICIs for advanced cancer. ICI treatment may be safely used in patients with existing HBV infection or chronic hepatitis B, accompanied by regular monitoring and appropriate antiviral prophylaxis if necessary.

Hepatitis due to hepatitis B virus (HBV) reactivation can be serious and potentially fatal, but is preventable. HBV reactivation is most commonly reported in patients receiving chemotherapy, especially rituximab-containing therapy for hematological malignancies and those receiving stem cell transplantation. Patients with inactive and even resolved HBV infection still have persistence of HBV genomes in the liver. The expression of these silent genomes is controlled by the immune system. Suppression or ablation of immune cells, most importantly B cells, may lead to reactivation of seemingly resolved HBV infection. Thus, all patients with hematological malignancies receiving anticancer therapy should be screened for active or resolved HBV infection by blood tests for hepatitis B surface antigen (HBsAg) and antibody to hepatitis B core antigen. Patients found to be positive for HBsAg should be given prophylactic antiviral therapy. For patients with resolved HBV infection, there are two approaches. The first is pre-emptive therapy guided by serial HBV DNA monitoring, and treatment with antiviral therapy as soon as HBV DNA becomes detectable. The second approach is prophylactic antiviral therapy, particularly for patients receiving high-risk therapy, especially anti-CD20 monoclonal antibody or hematopoietic stem cell transplantation. Entecavir and tenofovir are the preferred antiviral choices. Many new effective therapies for hematological malignancies have been introduced in the past decade, for example, chimeric antigen receptor (CAR)-T cell therapy, novel monoclonal antibodies, bispecific antibody drug conjugates, and small molecule inhibitors, which may be associated with HBV reactivation. Although there is limited evidence to guide the optimal preventive measures, we recommend antiviral prophylaxis in HBsAg-positive patients receiving novel treatments, including Bruton's tyrosine kinase inhibitors, B-cell lymphoma 2 inhibitors, and CAR-T cell therapy. Further studies are needed to determine the risk of HBV reactivation with these agents and the best prophylactic strategy.