Hepatitis B reactivation and immune check point inhibitors

Immune Checkpoint Inhibitors in Hepatocellular Carcinoma and Their Hepatic-Related Side Effects: A Review

Primary liver cancer is one of the leading causes of cancer mortality worldwide, with hepatocellular carcinoma (HCC) being the most prevalent type of liver cancer. The prognosis of patients with advanced, unresectable HCC has historically been poor. However, with the emergence of immunotherapy, specifically immune checkpoint inhibitors (ICIs), there is reason for optimism. Nevertheless, ICIs do not come without risk, especially when administered in patients with HCC, given their potential underlying poor hepatic reserve. Given their novelty in the management of HCC, there are few studies to date specifically investigating ICI-related side effects on the liver in patients with underlying HCC. This review will serve as a guide for clinicians on ICIs' role in the management of HCC and their potential side effect profile. There will be a discussion on ICI-related hepatotoxicity, the potential for hepatitis B and C reactivation with ICI use, the potential for the development of autoimmune hepatitis with ICI use, and the risk of gastrointestinal bleeding with ICI use. As ICIs become more commonplace as a treatment option in patients with advanced HCC, it is imperative that clinicians not only understand the mechanism of action of such agents but also understand and are able to identify hepatic-related side effects.

Updates on the immunopathology and genomics of severe cutaneous adverse drug reactions

Severe cutaneous adverse reactions (SCARs) such as Stevens-Johnson syndrome, toxic epidermal necrolysis (SJS/TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS)/drug-induced hypersensitivity syndrome (DIHS) cause significant morbidity and mortality and impede new drug development. HLA class I associations with SJS/TEN and drug reaction with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome have aided preventive efforts and provided insights into immunopathogenesis. In SJS/TEN, HLA class I-restricted oligoclonal CD8+ T-cell responses occur at the tissue level. However, specific HLA risk allele(s) and antigens driving this response have not been identified for most drugs. HLA risk alleles also have incomplete positive and negative predictive values, making truly comprehensive screening currently challenging. Although, there have been key paradigm shifts in knowledge regarding drug hypersensitivity, there are still many open and unanswered questions about SCAR immunopathogenesis, as well as genetic and environmental risk. In addition to understanding the cellular and molecular basis of SCAR at the single-cell level, identification of the MHC-restricted drug-reactive self- or viral peptides driving the hypersensitivity reaction will also be critical to advancing premarketing strategies to predict risk at an individual and drug level. This will also enable identification of biologic markers for earlier diagnosis and accurate prognosis, as well as drug causality and targeted therapeutics.

Identification of antibodies cross-reactive with woodchuck immune cells and activation of virus-specific and global cytotoxic T cell responses by anti-PD-1 and anti-PD-L1 in experimental chronic hepatitis B and persistent occult hepadnaviral infection

Woodchuck (Marmota monax) infected with woodchuck hepatitis virus (WHV) is the most pathogenically compatible naturally occurring model of human hepatitis B virus (HBV) infection, chronic hepatitis B, and HBV-induced hepatocellular carcinoma. This system plays a crucial role in discovery and preclinical evaluation of anti-HBV therapies. Its utilization remains tempered by the relatively narrow range of validated immunologic and molecular tools. We evaluated commercial antibodies against immune cell phenotypic markers and T cell molecules for cross-reactivity with woodchuck antigenic equivalents. The confirmed antibodies against programed cell death protein-1 (PD-1) and its ligand (PD-L1) were examined for ex vivo ability to activate WHV-specific, global and bystander cytotoxic T cells (CTLs) in chronic hepatitis and asymptomatic infection persisting after self-resolved acute hepatitis. Examination of 65 antibodies led to identification or confirmation of 23 recognizing woodchuck T, regulatory T, B and natural killer cells, T cell-associated PD-1, PD-L1, CTLA-4 and TIM-3 molecules, CD25 and CD69 markers of T cell activation, and interferon gamma (IFNγ). Antibodies against woodchuck PD-1 and PD-L1 triggered in vitro highly individualized WHV-specific and global activation of CTLs in both chronic hepatitis and persistent occult infection. WHV-specific CTLs were more robustly augmented by anti-PD-1 than by anti-PD-L1 in chronic hepatitis, while global IFNγ-positive CTL response was significantly suppressed in chronic hepatitis compared to persistent occult infection. Anti-PD-1 and anti-PD-L1 also occasionally activated CTLs to specificities other than those tested suggesting their potency to trigger side effects. This was particularly apparent when T cells from chronic hepatitis were treated with anti-PD-L1. The current findings indicate that inhibition of the PD-1/PD-L1 pathway could reactivate virus-specific and global T cell responses in both chronic hepatitis and asymptomatic persistent infection. They suggest a mechanism of potential reactivation of clinically silent infection during anti-PD-1/PD-L1 treatment and indicate that this therapy may also subdue occult HBV infection.

Infections Simulating Immune Checkpoint Inhibitor Toxicities: Uncommon and Deceptive

Use of immune checkpoint inhibitors (ICIs), a revolutionary treatment in modern oncology, is frequently complicated by immune-related adverse events (irAEs), which can be confused with infections, and vice versa, thus complicating management decisions. In this study, we review the published cases of infections as simulators of irAEs in cancer patients.

Hepatitis B virus reactivation in patients undergoing immune checkpoint inhibition: systematic review with meta-analysis

PURPOSE

Immune checkpoint inhibitors (ICIs) have been explored as first-line treatment in various types of previously untreatable malignancies, while limited evidence is available on the management of hepatitis B virus (HBV) in patients undergoing immunotherapy. We systematically reviewed data concerning challenges of hepatic adverse events including HBV reactivation and hepatitis in patients with chronic HBV infection undergoing immunotherapy.

METHODS

A systematic search was conducted in Medline, web of science, Embase and Cochrane library up to May 31, 2022. Studies reporting the safety profile of ICIs in patients with HBV infection were eligible. Meta-analyses were conducted to generate odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

A total of 13 studies including 2561 patients were included for meta-analysis. The overall incidence rates of HBV reactivation in patients with chronic HBV infection and past HBV infection were 1.0% (95% CI 0-3%) and 0% (95% CI 0-0%), respectively. Among patients with chronic HBV infection, the incidence rates of HBV reactivation were 1.0% (95% CI 0-2%) and 10.0% (95% CI 4-18%) for patients with and without antiviral prophylaxis, respectively. Patients with chronic HBV infection were at a higher risk of HBV reactivation compared with those with past HBV infection [OR = 8.69, 95% CI (2.16-34.99)]. Antiviral prophylaxis significantly reduced the risk of HBV reactivation [OR = 0.12, 95% CI (0.02-0.67)] and HBV-associated hepatitis [OR = 0.05, 95% CI (0.01-0.28)] in patients with chronic HBV infection.

CONCLUSIONS

Prophylactic antiviral therapy should be administered to patients with chronic HBV infection undergoing anticancer immunotherapy. Patients with past HBV infection are at lower risk of HBV reactivation compared with those with chronic HBV infection, they could be initiated with antiviral prophylaxis or monitored with the intent of on-demand antiviral therapy.

Hepatotoxicity Induced by Biological Agents: Clinical Features and Current Controversies

Novel biological agents including cytokines and recombinant fusion proteins are increasingly prescribed for cancer, rheumatologic, autoimmune, and inflammatory diseases, and are currently being evaluated in hepatocellular carcinoma (HCC). They are classified by their mechanism of action and include tumor necrosis factor-alpha (TNF-α) antagonists, T cell mediated antitumor inhibitors, interleukin receptor antagonists, and immune checkpoint inhibitors (ICIs). Some ICIs cause frequent hepatotoxicity with a variable clinical, biochemical, and serological presentation, especially in patients receiving another immunomodulatory agent. Half of the cases of liver damage induced by biological agents spontaneously regress after drug withdrawal, but the others require steroid therapy. Unfortunately, there are no widely accepted recommendation for the use of corticosteroids in these patients, even though international cancer societies have their own guidelines. Differentiating drug-induced autoimmune hepatitis (DIAIH) from classic AIH is challenging for pathologists, but liver biopsy is valuable, particularly in cases with unclear clinical presentation. Interesting, novel histological patterns have been described in liver damage induced by these agents (i.e., endothelitis, ring granuloma and secundary sclerosing cholangitis associated with lymphocytic infiltration of cytotoxic CD8+T cells). Here, we describe the clinical and biochemical characteristics of patients with hepatotoxicity induced by TNF-α antagonists and ICIs. Controversial issues involved in the administration of corticosteroid therapy, and hepatitis B virus (HBV) reactivation induced by immunosuppressive therapy are also discussed.

Risk of Hepatitis B Virus Reactivation in Patients Treated With Immunotherapy for Anti-cancer Treatment

BACKGROUND & AIMS

Hepatitis B virus (HBV) reactivation is a well-known complication in patients with chronic hepatitis B treated with cytotoxic chemotherapy. However, the risk of HBV reactivation through use of immune checkpoint inhibitors (ICIs) is not well understood. Therefore, we aimed to evaluate the risk of HBV reactivation and hepatic adverse events in patients with cancer receiving ICIs according to cancer type and virologic serology.

METHODS

This historical cohort study included 3465 patients with cancer treated with ICIs between January 2015 and September 2020. The primary outcome was the occurrence of HBV reactivation, and the secondary outcome was presence of hepatic adverse events during ICI treatment.

RESULTS

The mean patient age was 62.2 years, and 68.8% of patients were men. Of the 3465 eligible patients, 511 (14.7%) showed hepatitis B surface antigen (HBsAg) positivity. The incidence rates of HBV reactivation of the total patients, HBsAg-positive patients, and HBsAg-negative patients were 0.14% (5/3465), 1.0% (5/511), and 0.0% (0/2954), respectively. Among HBsAg-positive patients, HBV reactivation occurred at a rate of 0.5% (2/409) and 2.9% (3/102) in patients with and without hepatocellular carcinoma, respectively. The HBV reactivation rates were 0.4% (2/464) and 6.4% (3/47) in patients with and without antiviral prophylaxis, respectively. Grade 3-4 hepatitis occurred in 23 (4.5%) HBsAg-positive, and 218 (7.4%) HBsAg-negative patients. No HBV-related fatality occurred. Only 2 patients (0.4%) experienced HBsAg seroclearance after ICI treatment among HBsAg-positive patients.

CONCLUSIONS

In general, HBV reactivation was rarely observed in patients with antiviral prophylaxis while undergoing ICI treatment. However, HBV reactivation may occur in HBsAg-positive patients without antiviral prophylaxis or noncompliant with antiviral prophylaxis.

Immunopathogenesis of Acute Flare of Chronic Hepatitis B: With Emphasis on the Role of Cytokines and Chemokines

Acute flares (AFs) of chronic hepatitis B usually occur during the immune-active stage (both immune clearance phase and immune reactivation phase), as the host immune system tries to control the virus. Successful host immune control over viral replication is usually presented as hepatitis B surface antigen seroclearance; however, 20–30% individuals with chronic hepatitis B may encounter repeated AFs with accumulative liver injuries, finally leading to the development of cirrhosis and hepatocellular carcinoma. AF can also develop in other clinical situations such as organ transplantation, cancer chemotherapy, and under treatment for chronic hepatitis B or treatment for chronic hepatitis C in patients with co-infected hepatitis B/hepatitis C. Understanding the natural history and immunopathogenesis of AF would help develop effective strategies to eradicate the virus and improve the clinical outcomes of patients with chronic hepatitis B. In this review article, the immunopathogenesis of AF, and the involvement of innate and adaptive immune responses on the development of hepatitis B flare will be briefly reviewed, with the emphasis on the role of cytokines and chemokines.

Novel strategies for the early diagnosis of hepatitis B virus reactivation

Hepatitis B virus (HBV) reactivation under systemic chemotherapy or immunosuppressive therapy is a serious complication among HBV-resolved patients. Some medications, such as more than 2 weeks of corticosteroid therapy, can influence HBV reactivation; therefore, screening tests that measure hepatitis B surface antigen (HBsAg), hepatitis B core antibody, and hepatitis B surface antibody before therapy are required. Additionally, because HBV reactivation has been reported in patients positive for HBsAg treated with immune checkpoint inhibitors (ICIs), the prophylactic administration of nucleos(t)ide analogues prior to administering ICIs is recommended for HBsAg-positive patients. Under these circumstances, highly sensitive novel biomarkers are expected to be used for the early diagnosis of HBV reactivation. A fully automated high-sensitivity HBsAg assay (detection limit: 5 mIU/ml) by Lumipulse HBsAg-HQ, with 10-fold higher sensitivity than that of conventional assays, is currently used. Furthermore, ultra-sensitive HBsAg assays using a semi-automated immune complex transfer chemiluminescence enzyme immunoassay (ICT-CLEIA; detection limit: 0.5 mIU/ml) have been developed. Recently, a fully automated, novel high-sensitivity hepatitis B core-related antigen assay (iTACT-HBcrAg; cut-off value: 2.1 Log U/mL) has been developed and reported. The utility of ICT-CLEIA and iTACT-HBcrAg for the diagnosis of HBV reactivation appears comparable to the use of HBV DNA. In this review, we provide the latest information related to medications that influence HBV reactivation and recently developed novel biomarkers that predict and monitor HBV reactivation.

Liver Inflammation and Hepatobiliary Cancers

Immune regulation has an important role in cancer development, particularly in organs with continuous exposure to environmental pathogens, such as the liver and gastrointestinal tract. Chronic liver inflammation can lead to the development of hepatobiliary cancers, namely hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (iCCA), or combined HCC (cHCC)-CCA. In this review, we discuss the link between oxidative stress and the hepatic immune compartments, as well as how these factors trigger hepatocyte damage, proliferation, and eventually cancer initiation and its sustainment. We further give an overview of new anticancer therapies based on immunomodulation.