Anti-PD-1-induced high-grade hepatitis associated with corticosteroid-resistant T cells: a case report

New advances in the study of PD-1/PD-L1 inhibitors-induced liver injury

The application of immune checkpoint inhibitors (ICIs) has made extraordinary achievements in tumor treatment. Among them, programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitors can improve the prognosis of advanced tumors, and have been widely used in clinical practice to treat many types of cancers. However, excessive immune response can also induce immune-related adverse events (irAEs) involving many organs. Of these, immune-related liver injury is the relatively common and carries the highest morbidity, which has attracted the attention of hepatologists all over the world. The incidence of this type of liver injury depends specifically on factors such as the type of drug being combined, viral infection, type of cancer and liver transplantation. Although there is no unanimity on the mechanism of PD-1/PD-L1 inhibitor-induced liver injury, in this review, we also summarize the current evidence that provides insights into the pathogenesis of PD-1/PD-L1 inhibitor-induced liver injury, including the fact that PD-1/PD-L1 inhibitors cause reactivation of CTLs, aberrant presentation of autoantigens, hepatic immune tolerance environment is disrupted, and cytokine secretion, among other effects. Patients usually develop liver injury after the use of PD-1/PD-L1 inhibitors, and clinical symptoms mainly include weakness, muscle pain, nausea and vomiting, and jaundice. Histologically, the main manifestation is lobular hepatitis with lobular inflammatory infiltration. Since the specific biomarkers for PD-1/PD-L1 inhibitor-associated liver injury have not been identified yet, alpha-fetoprotein, IL-6, and IL-33 have the potential to be biomarkers for predicting this type of liver injury in the future, but this requires further research. We also describe the examination and treatment of this type of liver injury, which usually includes eliminating related influencing factors, regularly monitoring liver function, temporarily retaining or permanently stopping ICIs treatment according to the severity of toxicity, and using corticosteroids. This review may provide useful information for the future clinical practice of PD-1/PD-L1 inhibitors.

Corticosteroid-resistant immune-related adverse events: a systematic review

Immune checkpoint inhibitor (ICI) treatment has become an important therapeutic option for various cancer types. Although the treatment is effective, ICI can overstimulate the patient's immune system, leading to potentially severe immune-related adverse events (irAEs), including hepatitis, colitis, pneumonitis and myocarditis. The initial mainstay of treatments includes the administration of corticosteroids. There is little evidence how to treat steroid-resistant (sr) irAEs. It is mainly based on small case series or single case reports. This systematic review summarizes available evidence about sr-irAEs. We conducted a systematic literature search in PubMed. Additionally, we included European Society for Medical Oncology, Society for Immunotherapy of Cancer, National Comprehensive Cancer Network and American Society of Clinical Oncology Guidelines for irAEs in our assessment. The study population of all selected publications had to include patients with cancer who developed hepatitis, colitis, pneumonitis or myocarditis during or after an immunotherapy treatment and for whom corticosteroid therapy was not sufficient. Our literature search was not restricted to any specific cancer diagnosis. Case reports were also included. There is limited data regarding life-threatening sr-irAEs of colon/liver/lung/heart and the majority of publications are single case reports. Most publications investigated sr colitis (n=26), followed by hepatitis (n=21), pneumonitis (n=17) and myocarditis (n=15). There is most data for mycophenolate mofetil (MMF) to treat sr hepatitis and for infliximab, followed by vedolizumab, to treat sr colitis. Regarding sr pneumonitis there is most data for MMF and intravenous immunoglobulins (IVIG) while data regarding infliximab are conflicting. In sr myocarditis, most evidence is available for the use of abatacept or anti-thymocyte globulin (ATG) (both with or without MMF) or ruxolitinib with abatacept. This review highlights the need for prompt recognition and treatment of sr hepatitis, colitis, pneumonitis and myocarditis. Guideline recommendations for sr situations are not defined precisely. Based on our search, we recommend-as first line treatment-(1) MMF for sr hepatitis, (2) infliximab for sr colitis, followed by vedolizumab, (3) MMF and IVIG for sr pneumonitis and (4) abatacept or ATG (both with or without MMF) or ruxolitinib with abatacept for sr myocarditis. These additional immunosuppressive agents should be initiated promptly if there is no sufficient response to corticosteroids within 3 days.

Checkpoint inhibitor hepatotoxicity: pathogenesis and management

Immunotherapy, including immune checkpoint inhibitor (ICI) therapy, has been a paradigm shift in cancer therapeutics, producing durable cancer responses across a range of primary malignancies. ICI drugs increase immune activity against tumor cells, but may also reduce immune tolerance to self-antigens, resulting in immune-mediated tissue damage. ICI-associated hepatotoxicity usually manifests as hepatocellular enzyme elevation and may occur in 2%-25% of ICI-treated patients. Although ICI-associated hepatotoxicity is clinically and pathologically distinct from idiopathic autoimmune hepatitis, our understanding of its pathogenesis continues to evolve. Pending greater understanding of the pathophysiology, mainstay of management remains through treatment with high-dose corticosteroids. This approach works for many patients, but up to 30% of patients with high-grade hepatotoxicity may not respond to corticosteroids alone. Furthermore, atypical cholestatic presentations are increasingly recognized, and rare cases of fulminant hepatitis due to ICI hepatotoxicity have been reported. Optimal management for these challenging patients remains uncertain. Herein, we review the current understanding of pathogenesis of ICI-associated toxicities, with a focus on hepatotoxicity. Based on the existing literature, we propose evolving management approaches to incorporate strategies to limit excess corticosteroid exposure, and address rare but important presentations of cholestatic hepatitis and fulminant liver failure. Finally, as ICI hepatotoxicity frequently occurs in the context of treatment for advanced malignancy, we review the impact of hepatotoxicity and its treatment on cancer outcomes, and the overall safety of re-challenge with ICI, for patients who may have limited treatment options.

Effectiveness of tacrolimus in a case of immune checkpoint inhibitor-induced hepatotoxicity that was refractory to steroids and mycophenolate mofetil

Immune checkpoint inhibitors (ICIs) sometimes induce immune-mediated hepatotoxicity (IMH), and corticosteroids and mycophenolate mofetil (MMF) are recommended for the treatment of IMH. However, there is no consensus on the treatment of IMH refractory to these drugs. Here, we report a case of refractory IMH that was successfully treated with tacrolimus. A 69-year-old man presented with liver injury after receiving durvalumab, an ICI, for lung cancer. He was diagnosed with IMH and received corticosteroids including methylprednisolone pulses and MMF, but his liver damage did not improve. Liver histology showed infiltration of inflammatory cells, mainly CD8 + T cells, in the portal area. Tacrolimus was added to corticosteroid and MMF to suppress mainly T cells. After the tacrolimus administration, the liver damage promptly improved. Since IMH is thought to be caused by activated CD8 + T-cell infiltration, T-cell suppression may be an effective treatment. This case suggests that tacrolimus may be an effective option for IMH refractory to corticosteroids or MMF if CD8 + T-cell infiltration is confirmed in the liver tissue.

Immune-mediated hepatitis induced by immune checkpoint inhibitors: Current updates and future perspectives

In recent years, cancer immunotherapy has made remarkable achievements. Immune checkpoint inhibitors (ICIs) have been used successfully in several types of cancer in the past decade. However, expanded indication and increased use of Immune checkpoint inhibitors have resulted in increased reports of toxicity called immune-related adverse events (irAEs). Due to the unique immunological characteristics of the liver, a hepatic immune-related adverse events has also been reported, which is usually termed Immune-mediated hepatitis (IMH). So far, it is generally considered that the mechanism of IMH induced by Immune checkpoint inhibitors is mainly the overactivation of T cells. It has been reported that the incidence of IMH ranges from 1% to 15%. Because of the lack of specific markers, a diagnosis of exclusion of IMH is critical. Although most IMH is mild and recoverable, several death cases have been reported, which has been increasingly concerned. This review summarizes the current understanding of the pathophysiology, epidemiology, diagnosis, management and prognosis of IMH caused by Immune checkpoint inhibitors. It also discusses the controversial issues in IMH, such as the role of liver biopsy, grading criteria, risk factors, rational treatment strategies with steroids, and the timing of Immune checkpoint inhibitors rechallenging, which may provide helpful information for IMH in future clinical practice.

The Current status of steroid-refractory immune-checkpoint-inhibitor-related hepatotoxicity

ICI-related hepatotoxicity (IRH) is becoming more and more common as immune checkpoint inhibitors (ICIs) have begun to be increasingly approved and used in combination with other anti-tumor drugs worldwide. Steroids are the first choice for the treatment of IRH, but the subsequent optimal treatment algorithm remains unclear if the disease progresses to steroid-refractory IRH. Therefore, in this paper we reviewed all the pertinent literature on steroid-refractory IRH to the greatest extent possible in an attempt to provide information on which to base an update of the treatment algorithm for steroid-refractory IRH.

Incidence rate and treatment strategy of immune checkpoint inhibitor mediated hepatotoxicity: A systematic review

Background

A hepatic adverse event (HAE) is defined as a liver injury that occurs following immune checkpoint inhibitor (ICI) administration in oncology Patients. Immune-mediated hepatotoxicity (IMH) is a type of HAE directly caused by ICI and is associated with immune system hyperactivation. HAE incidence varies across different clinical studies. This study aimed to explore the risk factors of HAE and establish a personalized IMH treatment strategy.

Methods

Randomized controlled trials (RCTs) on ICIs and case reports related to IMH were collected and summarized separately. Meta-analysis was performed using Review Manager (version 5.0), whereas correlation analysis and linear regression were performed using SPSS (version 24.0) to evaluate any correlations between the two variables.

Results

Overall, 36 RCTs containing 18,515 patients and 39 case reports met our inclusion criteria. The ICI administration increased the HAE risk (risk ratio [RR] ​= ​1.40) as well as severe HAE (RR ​= ​2.55). The overall HAE incidence and severe incidence were about 15.3% and 4.3%, respectively. Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors have a higher incidence of HAE than programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) inhibitors. Finally, we found a positive correlation between the onset time of IMH and the recovery time of liver injury.

Conclusions

ICI administration increased the incidence risk of HAE, especially in patients treated with CTLA-4 inhibitors. Regarding IMH treatment, the glucocorticoid dosage must be individually reduced according to the severity and onset time of HAE.

Immunotherapy-induced Hepatotoxicity: A Review

Immune checkpoint inhibitors (ICIs) suppress the function of immune checkpoints, which are involved in downregulating immune responses. These lead to an increased activation of the function of T cells, increased release of cytokines, and decreased activity of regulatory T cells. This allows for a more significant and less regulated immune response and subsequent enhanced cytotoxic activity against cancer cells. A number of cancers are now being treated with these agents and this increased use has resulted in more reports of toxicity. While almost every organ can be affected, the skin, gastrointestinal tract, liver, and endocrine glands are most commonly involved. It is necessary that gastroenterologists and hepatologists familiarize themselves with diagnostic steps and management plan in patients with these undesirable outcomes. When assessing for possible ICIs induced hepatotoxicity, it is of utmost importance to use a formal scoring system such as the Roussel Uclaf causality assessment method (RUCAM) to assess for risk factors, alternative causes, and response to cessation and re-exposure of a given drug. While this review is based on studies with and without RUCAM, the conclusions were carefully established mainly from studies that used RUCAM. The aim of this review is to provide information on the epidemiology, risk factors, clinical presentation, diagnostic tools, and management plan based on the most recent studies of immunotherapy-induced hepatotoxicity.

Immune-Mediated Hepatitis During Immune Checkpoint Inhibitor cancer Immunotherapy: Lessons From Autoimmune Hepatitis and Liver Immunology

Immune checkpoint inhibitors (ICI) are being increasingly used to successfully treat several types of cancer. However, due to their mode of action, these treatments are associated with several immune-related adverse events (irAEs), including immune-mediated autoimmune-like hepatitis in 5 to 10% of cases. The specific immune mechanism responsible for the development of immune-mediated liver injury caused by immune checkpoint inhibitors (ILICI) is currently unknown. This review summarizes the current knowledge on hepatic irAEs during cancer immunotherapy. It also addresses the clinical management of ILICI and how it is becoming an increasingly important clinical issue. Clinical, histological, and laboratory features of autoimmune hepatitis (AIH) and ILICI are compared, and their shared and distinctive traits are discussed in an effort to better understand the development of hepatic irAEs. Finally, based on the current knowledge of liver immunology and AIH pathogenesis, we propose a series of events that could trigger the observed liver injury in ICI-treated patients. This model could be useful in the design of future studies aiming to identify the specific immune mechanism(s) at play in ILICI and improve immune checkpoint inhibitor cancer immunotherapy.

Mycophenolate mofetil for immune checkpoint inhibitor‐related hepatotoxicity relapsing during dose reduction of corticosteroid: A report of two cases and literature review

Background

Immune checkpoint inhibitors (ICIs) sometimes cause immune‐related liver injury, which can lead to cessation of treatment, hospitalization, and even mortality. Although high‐dose corticosteroids are usually effective in treatment of ICI‐related liver injury, one fifth of affected patients require additional immunosuppressive therapy. It remains uncertain how best to treat ICI‐related liver injury that relapses under corticosteroid therapy after temporary remission.

Case

Here we report two cases of ICI‐related liver injury successfully treated with mycophenolate mofetil (MMF). In the first case, a 74‐year‐old man with stage IIIA lung cancer underwent curative chemoradiotherapy. After the second infusion of durvalumab, grade 3 ICI‐related liver injury (mixed pattern) developed. In the second case, a 46‐year‐old man with stage IVB lung cancer received pembrolizumab‐containing chemotherapy. After the first cycle, grade 2 ICI‐related hepatitis developed. In the both cases, liver injury improved with high‐dose prednisolone but relapsed during tapering of the drug. After liver biopsy was performed to confirm the diagnosis of ICI‐related liver injury, MMF (2000 mg/day) was added. MMF was effective for both patients and permitted discontinuation or reduction of prednisolone.

Conclusion

MMF appears to be an appropriate treatment option for ICI‐related liver injury that respond to high‐dose corticosteroids but relapse during steroid tapering.

Downregulated cytotoxic CD8+ T-cell identifies with the NKG2A-soluble HLA-E axis as a predictive biomarker and potential therapeutic target in keloids

Keloids are an abnormal fibroproliferative wound-healing disease with a poorly understood pathogenesis, making it difficult to predict and prevent this disease in clinical settings. Identifying disease-specific signatures at the molecular and cellular levels in both the blood circulation and primary lesions is urgently needed to develop novel biomarkers for risk assessment and therapeutic targets for recurrence-free treatment. There is mounting evidence of immune cell dysregulation in keloid scarring. In this study, we aimed to profile keloid scar tissues and blood cells and found that downregulation of cytotoxic CD8+ T cells is a keloid signature in the peripheral blood and keloid lesions. Single-cell RNA sequencing revealed that the NKG2A/CD94 complex was specifically upregulated, which might contribute to the significant reduction in CTLs within the scar tissue boundary. In addition, the NKG2A/CD94 complex was associated with high serum levels of soluble human leukocyte antigen-E (sHLA-E). We subsequently measured sHLA-E in our hospital-based study cohort, consisting of 104 keloid patients, 512 healthy donors, and 100 patients with an interfering disease. The sensitivity and specificity of sHLA-E were 83.69% (87/104) and 92.16% (564/612), respectively, and hypertrophic scars and other unrelated diseases exhibited minimal interference with the test results. Furthermore, intralesional therapy with triamcinolone combined with 5-fluorouracil drastically decreased the sHLA-E levels in keloid patients with better prognostic outcomes, while an incomplete reduction in the sHLA-E levels in patient serum was associated with higher recurrence. sHLA-E may effectively serve as a diagnostic marker for assessing the risk of keloid formation and a prognostic marker for the clinical outcomes of intralesional treatment.

Anti-nuclear antibody and a granuloma could be biomarkers for iCIs-related hepatitis by anti-PD-1 treatment

It has been reported that various kinds of immune checkpoint inhibitors (iCIs) could induce immune-related liver damage. We should focus on the programmed cell death-receptor-1 (PD-1) antibody and non-small cell lung cancer (NSCLC) to analyze the characteristics of hepatitis related to iCIs and find factors that could be useful biomarkers for the diagnosis. A single-center retrospective study of 252 NSCLC patients who received PD-1 antibody (nivolumab or pembrolizumab). Some of the biochemical markers and immunological markers were analyzed during PD-1-antibody treatment with or without ALT elevation. Histopathological features were reviewed by a single expert of hepatic pathology focusing on the following features: fibrosis, portal inflammation, lobular inflammation, lobular necrosis. The formation of macro- and micro-granulomas was also evaluated. The frequency of liver damage induced by nivolumab including grade 1 to 4 (ALT) was 41.9% (78/186 patients). The positive rate of anti-nuclear antibody in the nivolumab group with iCIs-related hepatitis was significantly higher than that in the nivolumab group without iCIs-related hepatitis (p = 0.00112). Granulomatous changes were significantly increased in patients with iCIs-related hepatitis compared with DILI and AIH patients (p < 0.05). The ratios of inflammatory cells CD4/CD8, and CD138/CD3 in ICIs-related hepatitis were significantly lower than those in AIH or DILI patients (p < 0.05). We demonstrated that the pre-existing ANA and characteristic liver histology including CD8⁺ cells dominancy and granulomatous hepatitis could be biomarkers for the diagnosis of iCIs-related hepatitis in the NSCLC with anti-PD-1 therapy.

Hepatobiliary and Pancreatic Adverse Events

The expanded approval of immune checkpoint inhibitors (ICIs) for the treatment of multiple cancer types has offered patients more opportunities in treatment selection and survival.Hepatotoxicity is a well-recognized immune-related adverse event (irAE) associated with treatment with ICI. It is considered a type of drug-induced liver injury (DILI). Depending on the specific ICI and whether the patient receives single- or dual-drug therapy, the incidence of hepatotoxicity in general could be as high as 30%. As more patients receive treatment with ICI, more cases of hepatotoxicity are expected to occur. Clinicians must exercise close pharmacovigilance to recognize liver-related irAEs early.ICI-mediated hepatobiliary toxicity (or "IMH") generally presents as asymptomatic elevations of alanine transaminase and aspartate transaminase, with or without alkaline phosphatase elevation. Some patients may present with jaundice, fever, or malaise. Rarely, it may cause liver failure and death. The diagnosis of IMH is made after careful exclusion of other causes of acute hepatitis based on medical history, laboratory evaluation, imaging, and liver histological findings. In clinically significant cases of IMH, the management involves discontinuation of ICI followed by close monitoring and the initiation of immunosuppression. Current society guidelines, which are not based on robust evidence, specify treatment recommendations depending on the grade of liver injury, according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. However, our clinical experience suggests possible alternatives, including lower corticosteroid dosing with adjunct therapies. Whereas current guidelines endorse permanent cessation of future ICI treatment in patients diagnosed with grades 3-4 IMH, published clinical experience suggests potential for flexibility when assessing for candidacy of resuming ICI.Because histologic bile duct injury has been observed in cases ascribed to IMH, ICI-mediated cholangiopathic disease probably exists on a spectrum within IMH. Even extrahepatic bile duct involvement has been observed. This phenotype warrants special considerations in treatment and surveillance.ICI-related cholecystitis has been rarely reported in the literature. Management follows current standards of care for typical cases of cholecystitis. No relationship with ICI-mediated cholangiopathic disease has been observed.Assessing for and managing ICI-associated pancreatic injury remain challenging to the clinician. Many cases of asymptomatic serum lipase elevation are detected on routine labs without clinical signs or symptoms of typical acute pancreatitis. However, symptomatic patients should be initially managed like traditional cases of acute pancreatitis requiring hospitalization for evaluation and inpatient management.

Drug-Induced Liver Injury: Highlights and Controversies in the Recent Literature

Drug-induced liver injury (DILI) remains an important, yet challenging diagnosis for physicians. Each year, additional drugs are implicated in DILI and this year was no different, with more than 1400 articles published on the subject. This review examines some of the most significant highlights and controversies in DILI-related research over the past year and their implications for clinical practice. Several new drugs were approved by the US Food and Drug Administration including a number of drugs implicated in causing DILI, particularly among the chemotherapeutic classes. The COVID-19 pandemic was also a major focus of attention in 2020 and we discuss some of the notable aspects of COVID-19-related liver injury and its implications for diagnosing DILI. Updates in diagnostic and causality assessments related to DILI such as the Roussel Uclaf Causality Assessment Method are included, mindful that there is still no single biomarker or diagnostic tool to unequivocally diagnose DILI. Glutamate dehydrogenase received renewed attention as being more specific than alanine aminotransferase. There were a few new reports of previously unrecognized hepatotoxins, including immune modulators and novel gene therapy drugs that we highlight. Updates and new developments of previously described hepatotoxins, such as immune checkpoint inhibitors and anti-tuberculosis drugs are reviewed. Finally, novel technologies such as organoid culture systems to better predict DILI preclinically may be coming of age and determinants of hepatocyte loss, such as calculating P_ALT are poised to improve our current means of estimating DILI severity and the risk of acute liver failure.

When steroids are not enough in immune-related hepatitis: current clinical challenges discussed on the basis of a case report

Unleashing adaptive immunity via immune checkpoint inhibitors (ICPIs) in many cancer types led to durable antitumor responses and prolonged survivals and also added some new immune-related adverse events (irAEs) to the ‘old-fashioned’ safety profile of chemotherapy. Among bowel and endocrine irAEs, immune-mediated hepatotoxicity/hepatitis is a less common and far less well-studied toxicity, which, however, could develop into a serious complication, especially when it becomes persistent or refractory to steroids. Its incidence, onset and severity vary widely, depending on the type of underlying treated cancer, the class, the dosage and the duration of immunotherapy as well as the way of its administration (as a single agent or in combination with other ICPI or chemotherapy). In this study, we present a patient with metastatic melanoma who developed severe steroid-resistant ir-hepatitis after treatment with ipilimumab and required triple concurrent immunosuppression with prednisolone, mycofenolate mofetil and tacrolimus in order for his liver toxicity to be resolved. Intrigued by this case, we focused further on melanoma, as the disease-paradigm of immunotherapy in cancer, reviewed the reported incidence of hepatotoxicity among phase III ICPIs-containing trials on melanoma and discussed the main clinical considerations regarding the diagnosis and the management of persistent/steroid-refractory ir-hepatitis. As more clinical experience is gradually gained on this challenging topic, better answers are provided to questions about the appropriate diagnostic workup, the necessity of liver biopsy, the available immunosuppressive options beyond corticosteroids (their combinations and/or their sequence) as well as the correct decision on withdrawing or resuming immunotherapy. Nonetheless, a thorough multidisciplinary discussion is still required to individualize the overall approach in each case after failure of steroids.

Morphology of tumor and nontumor tissue in liver resection specimens for hepatocellular carcinoma following nivolumab therapy

Nivolumab is an immune checkpoint inhibitor (ICI) approved for treatment of many cancers, including hepatocellular carcinoma (HCC). Liver injury is a known complication in patients treated with nivolumab for nonliver tumors. To date, the morphologic changes to tumor and nontumor liver have not been well-characterized in HCC patients. We identified 20 patients who underwent partial hepatectomy or liver transplantation after receiving nivolumab for HCC. Demographics, laboratory values, and imaging results were obtained from medical records. All available slides from resection specimens were evaluated for tumor necrosis, tumor-infiltrating lymphocytes (TILs), and features of liver injury. Patients in the study included 16 males and 4 females with median age of 56 years. The underlying liver disease was HBV in 10, HCV in 6, and unknown/other in 4. Twelve patients were treated with nivolumab in the neoadjuvant setting, whereas eight were treated with nivolumab, usually along with other therapies, before undergoing liver transplantation. On review of resection specimens, three patients (all from the neoadjuvant group) demonstrated marked treatment response attributable to nivolumab. TILs were present in 17/20 cases. One case that showed treatment response in the neoadjuvant group demonstrated non-necrotizing granulomas and prominent bile duct intraepithelial lymphocytes (IELs) in the nontumor liver. One case from the transplant group showed bile duct damage and prominent ductular reaction after long-term nivolumab therapy (32 doses). Our findings indicate that nivolumab is effective in a subset of patients, including in the neoadjuvant setting. Granulomas and bile duct IELs are rare findings in cases treated with nivolumab but, when seen, may indicate potential response to therapy. Bile duct damage and ductular reaction may be manifestations of long-term nivolumab therapy. Future prospective and longitudinal studies with pretreatment tumor biopsies may help identify patients apt to respond to ICI therapy and further characterize patterns of ICI-related liver injury.

Checkpoint Inhibitors and Hepatotoxicity

Uncontrolled immune response to a pathogen or any protein can lead to tissue damage and autoimmune diseases, that represent aberrant immune responses of the individual to its own cells and/or proteins. The immune checkpoint system is the regulatory mechanism that controls immune responses. Tumor cells escape the immune surveillance mechanism, avoiding immune detection and elimination by activating these checkpoints and suppressing the anti-tumor response, thus allowing formation of tumors. Antigenic modulation facilitates masking and contributes to the escape of tumor cells. In addition, there are growing cell promoters, like transforming growth factor β (TGF-β), contributing to escape mechanisms. Targeting the immunological escape of malignant cells is the basis of immune oncology. Checkpoint inhibitors, cytokines and their antibodies may enhance the immune system’s response to tumors. Currently, immunomodulatory agents have been designed, evaluated in clinical trials and have been approved by both European and United States Drug Agencies. The present review is a reflection of the increasingly important role of the checkpoint inhibitors. Our aim is to review the side effects with the emphasis on hepatic adverse reactions of these novel biological drug interventions.

The Multiple Potential Biomarkers for Predicting Immunotherapy Response-Finding the Needle in the Haystack

Immune checkpoint inhibitors (ICIs) are being increasingly utilised in a variety of advanced malignancies. Despite promising outcomes in certain patients, the majority will not derive benefit and are at risk of potentially serious immune-related adverse events (irAEs). The development of predictive biomarkers is therefore critical to personalise treatments and improve outcomes. A number of biomarkers have shown promising results, including from tumour (programmed cell death ligand 1 (PD-L1), tumour mutational burden (TMB), stimulator of interferon genes (STING) and apoptosis-associated speck-like protein containing a CARD (ASC)), from blood (peripheral blood mononuclear cells (PBMCs), circulating tumour DNA (ctDNA), exosomes, cytokines and metal chelators) and finally the microbiome.

Single-Cell Immune Profiling in Coronary Artery Disease: The Role of State-of-the-Art Immunophenotyping With Mass Cytometry in the Diagnosis of Atherosclerosis

Coronary artery disease remains the leading cause of death globally and is a major burden to every health system in the world. There have been significant improvements in risk modification, treatments, and mortality; however, our ability to detect asymptomatic disease for early intervention remains limited. Recent discoveries regarding the inflammatory nature of atherosclerosis have prompted investigation into new methods of diagnosis and treatment of coronary artery disease. This article reviews some of the highlights of the important developments in cardioimmunology and summarizes the clinical evidence linking the immune system and atherosclerosis. It provides an overview of the major serological biomarkers that have been associated with atherosclerosis, noting the limitations of these markers attributable to low specificity, and then contrasts these serological markers with the circulating immune cell subtypes that have been found to be altered in coronary artery disease. This review then outlines the technique of mass cytometry and its ability to provide high-dimensional single-cell data and explores how this high-resolution quantification of specific immune cell subpopulations may assist in the diagnosis of early atherosclerosis in combination with other complimentary techniques such as single-cell RNA sequencing. We propose that this improved specificity has the potential to transform the detection of coronary artery disease in its early phases, facilitating targeted preventative approaches in the precision medicine era.

Prognostic role of gamma-glutamyl transferase in metastatic melanoma patients treated with immune checkpoint inhibitors

BACKGROUND

Hepatic immune-related adverse events (irAE) including elevated liver function tests (transaminases) occur in 1.4-22.3% of melanoma patients receiving immune checkpoint inhibitors (ICPI) and constitute a potentially serious toxicity that is challenging to treat. In contrast to the liver transaminases alanine aminotransferase (ALT) and aspartate aminotransferase (AST), only little is known about the frequency and impact of gamma-glutamyl transferase (GGT) elevations.

METHODS

GGT determined prior to and during therapy of metastatic melanoma patients treated with ICPI were retrospectively assessed in two independent cohorts (PD-1: n = 218, Ipi + Nivo: n = 148). Overall survival (OS) and best objective response were analyzed according to baseline and immune-related GGT (irGGT) elevations during treatment.

RESULTS

In multivariate analysis, OS was reduced in patients with elevated baseline GGT (PD-1 group: hazard ratio [HR] 1.76, p = .0073; Ipi + Nivo group: HR 1.77, p = .032). Immune-related GGT elevation was recorded in 17% (PD-1 group) and 38.5% (Ipi + Nivo group). Of these patients, the majority (81 and 68%, respectively) had normal ALT and AST and showed no clinical signs of hepatotoxicity. Patients who experienced irGGT elevation had superior response (PD-1 group: odds ratio [OR] 3.57, p = .00072; Ipi + Nivo group: OR 1.74, p = .12) and OS (PD-1 group: HR 0.37, p = .0016; Ipi + Nivo group: HR 0.33, p = .00050).

CONCLUSIONS

The frequency of hepatic irAE is currently underestimated. The addition of the sensitive enzyme GGT to the laboratory panel before and during therapy with ICPI allows to detect two to three times more patients developing hepatic or hepatobiliary toxicity than known so far. Immune-related GGT elevations correlate with response and favorable survival. Precis for use in the Table of Contents The frequency of hepatotoxicity under immune checkpoint blockade is currently underestimated. We suggest the addition of gamma-glutamyl transferase to the laboratory panel in checkpoint inhibitor patients for the detection of hepatobiliary toxicity.

Ex vivo enrichment of PRAME antigen-specific T cells for adoptive immunotherapy using CD137 activation marker selection

Objective

Adoptive immunotherapy with ex vivo expanded tumor‐specific T cells has potential as anticancer therapy. Preferentially expressed antigen in melanoma (PRAME) is an attractive target overexpressed in several cancers including melanoma and acute myeloid leukaemia (AML), with low expression in normal tissue outside the gonads. We developed a GMP‐compliant manufacturing method for PRAME‐specific T cells from healthy donors for adoptive immunotherapy.

Methods

Mononuclear cells were pulsed with PRAME 15‐mer overlapping peptide mix. After 16 h, activated cells expressing CD137 were isolated with immunomagnetic beads and cocultured with irradiated CD137^neg fraction in medium supplemented with interleukin (IL)‐2, IL‐7 and IL‐15. Cultured T cells were restimulated with antigen‐pulsed autologous cells after 10 days. Cellular phenotype and cytokine response following antigen re‐exposure were assessed with flow cytometry, enzyme‐linked immunospot (ELISPOT) and supernatant cytokine detection. Detailed phenotypic and functional analysis with mass cytometry and T‐cell receptor (TCR) beta clonality studies were performed on selected cultures.

Results

PRAME‐stimulated cultures (n = 10) had mean expansion of 2500‐fold at day 18. Mean CD3⁺ percentage was 96% with CD4:CD8 ratio of 4:1. Re‐exposure to PRAME peptide mixture showed enrichment of CD4 cells expressing interferon (IFN)‐γ (mean: 12.2%) and TNF‐α (mean: 19.7%). Central and effector memory cells were 23% and 72%, respectively, with 24% T cells expressing PD1. Mass cytometry showed predominance of Th1 phenotype (CXCR3⁺/CCR4^neg/CCR6^neg/Tbet⁺, mean: 73%) and cytokine production including IL‐2, IL‐4, IL‐8, IL‐13 and GM‐CSF (2%, 6%, 8%, 4% and 11%, respectively).

Conclusion

PRAME‐specific T cells for adoptive immunotherapy were enriched from healthy donor mononuclear cells. The products were oligoclonal, exhibited Th1 phenotype and produced multiple cytokines.

Management of Immune Checkpoint Inhibitor Toxicities

Immune checkpoint inhibitors (ICIs) have radically changed the clinical outcome of several cancers with durable responses. CTLA-4 (cytotoxic T lymphocyte antigen-4), PD-1 (programmed cell death protein 1) or PDL-1 (programmed cell death ligand protein 1) represent ICIs that can be used as monotherapy or in combination with other agents. The toxicity p\rofiles of ICIs differ from the side effects of cytotoxic agents and come with new toxicities like immune-related adverse events. Typically, these toxicities occur in all organs. However, the main organs affected are the skin, digestive, hepatic, lungs, rheumatologic, and endocrine. Most of the immune toxicity that occurs is low grade but some more severe toxicities can occur that require a rapid diagnosis and appropriate treatment. The recognition of symptoms by physicians and patient is necessary to resolve them rapidly and adapt treatment to allow the toxicity to resolve.

Balancing Cancer Immunotherapy Efficacy and Toxicity

Anti-programmed cell death-1 receptor/programmed cell death-1 receptor ligand-directed therapies are transforming cancer care, with durable antitumor responses observed in multiple cancer types. Toxicities arising from therapy are autoimmune in nature and may affect essentially any organ system. The immunologic basis of such toxities is complex, with contributions from T-cell activation and autoantibody generation. Although less recognized, hypersensitivity reactions are also possible. Although most toxicities resolve with systemic corticosteroids, some require second-line immunosuppression. Furthermore, the safety of drug rechallenge is not well characterized, with variable rates of toxicity flares arising with re-exposure. Herein, we review toxicities of immune checkpoint inhibitor therapies, particularly focusing on issues that allergists/immunologists may clinically encounter, including interstitial nephritis, skin toxicity, and risks associated with immunotherapy rechallenge.

Immune Related Adverse Events: Classification and Management Approaches in Advanced Kidney Cancer

Recent therapeutic advancements have incorporated immune checkpoint inhibitors (ICIs) into the management of metastatic renal cell carcinoma. Pivotal phase III trials have resulted in Food and Drug Administration approval for anti-programmed death 1/programmed death ligand 1 ICIs, either in combination with anti-cytotoxic T-lymphocyte antigen 4 ICIs or with vascular endothelial growth factor-directed targeted therapies, as standard-of-care frontline regimens. Immune checkpoint inhibitors offer improved clinical outcomes when compared to previous treatment options. However, these agents also present unique toxicity profiles collectively referred to as immune-related adverse events. Common immune-related adverse events include colitis, hepatitis, dermatitis, and thyroiditis. Rare toxicities, such as myocarditis and pneumonitis, have the potential for causing severe harm. Herein, we provide a case-based discussion of how to identify, grade, and manage irAEs in metastatic renal cell carcinoma.

Side effects and management in immunotherapy based on immune checkpoint inhibitors

Immune checkpoint inhibitors, which exert their antitumor effects by targeting suppressive immune molecules, are a class of monoclonal antibody drugs based on certain immune checkpoints. Cancer immunotherapies lead to unique toxicity profiles distinct from the toxicities of other cancer therapies, depending on their mechanism of action. Immune-related adverse events can involve any organ or system. These effects are frequently low grade and reversible, affecting the skin, gastrointestinal tract, liver, endocrine system, and lung most commonly. However, some adverse effects can be severe and life-threatening. Therefore, the effective management of immune-related adverse events and reducing the occurrence of grade 3-4 treatment-related adverse events are critical in optimizing treatment outcomes. In this review, we summarize the clinical guidelines and the latest studies, and focus on the common toxic effects and management of the adverse events related to anti-cytotoxic T lymphocyte-associated antigen-4 or programmed death-1/programmed death-ligand-1 monoclonal antibody drugs, in order to provide better management of immune-related adverse events.

Liver toxicity as a limiting factor to the increasing use of immune checkpoint inhibitors

Immune checkpoint inhibitors (ICIs) improve clinical outcomes in patients suffering from different types of cancer. Liver toxicity is one of the immune-related adverse events associated with immunotherapy; although not common, its management is challenging as it is extremely heterogeneous in terms of presentation and severity. Differences in the development and evolution of ICI-related toxicity in healthy or cirrhotic livers have not yet been elucidated. Assessing causality is key to diagnosing ICI-induced liver toxicity; liver biopsies can assist not only in the differential diagnosis but also in assessing the severity of histological liver damage. The current classification of severity overestimates the grade of liver injury and needs to be revised to reflect the views of hepatologists. Spontaneous improvements in ICI-related liver toxicity have been reported, so corticosteroid therapy should probably be individualised not systematic. The reintroduction of ICIs in a patient with previous immune-mediated hepatitis may be possible, but the risk/benefit ratio should be considered, as the risk factors for hepatitis recurrence are currently unclear. The management of these patients, requiring a balance between efficacy, toxicity and specific treatments, necessitates multidisciplinary collaboration. The incidence of immune-related liver toxicity will continue to rise based on the increasing use of ICIs for most cancers, mandating improved understanding and management of this complication.

Hepatotoxicity From Immune Checkpoint Inhibitors: A Systematic Review and Management Recommendation

Immune checkpoint inhibitors (ICIs) are monoclonal antibodies targeting immune checkpoint molecules. ICIs are an immunotherapy for the treatment of many advanced malignancies. The advent of ICIs has been a major breakthrough in the field of oncology, a fact recognized by the 2018 Nobel Prize in Physiology or Medicine being awarded for the discovery. The Food and Drug Administration approved the first ICI, ipilimumab, in 2011 for the treatment of metastatic melanoma. Seven ICIs are now used in clinical practice, including nivolumab and pembrolizumab for treatment of advanced hepatocellular carcinoma. ICIs are increasingly used across the spectrum of hepatobiliary neoplasia. The utility of ICI therapy has been limited by immune-related adverse reactions (irAEs) affecting multiple organ systems. Hepatotoxicity is an important irAE, occurring in up to 16% of patients receiving ICIs. Optimizing outcomes in patients receiving ICI therapy requires awareness of and familiarity with diagnosing and management of ICI-induced immune-mediated hepatotoxicity (IMH), including approaches to treatment and ICI dose management. The aim of this review article is to (1) provide a comprehensive, evidence-based review of IMH; (2) perform a systematic review of the management of IMH; and (3) present algorithms for the diagnosis and management of IMH.

Anti-programmed cell death-1 and anti-programmed cell death ligand-1 immune-related liver diseases: from clinical pivotal studies to real-life experience

INTRODUCTION

Monoclonal antibodies directed against programmed cell death-1 (anti-PD-1) and its ligand (anti-PD-L1) showed a significant efficacy among different immunogenic metastatic tumors such as melanoma, non-small cell lung cancer (NSCLC), renal cell carcinoma (RCC). Between immune-related adverse events (irAEs) dependent on immune checkpoint inhibitors (ICPIs), immune-related liver diseases are uncommon and a definitive diagnosis is not always feasible.

AREAS COVERED

We revised data from phase II/III clinical trials and real-world retrospective analyses on liver-related adverse events induced by anti-PD-1 (nivolumab/pembrolizumab) and anti-PD-L1 (atezolizumab) in advanced cancer populations (melanoma, NSCLC and RCC). Furthermore, we described clinical-pathological patterns of immune-related liver diseases in real-life.

EXPERT OPINION

Use of anti-PD-1 and anti-PD-L1 led to a paradigm shift in the management of patients with melanoma, NSCLC and RCC. IrAEs can occur potentially in any tissue, leading to discontinuation of ICPIs, at least in a small proportion of these patients, and to a negative impact on their prognosis. Hepatobiliary immune-related adverse events are underestimated due to inappropriate monitoring. Development of novel diagnostic and therapeutic strategies for cancer patients receiving ICPIs as well as the identification of predictive biomarkers of liver injury could allow a better patients' selection and improve clinical outcomes of immune-related liver diseases.

New therapeutic perspectives to manage refractory immune checkpoint-related toxicities

Immune checkpoint inhibitors are reshaping the prognosis of many cancer and are progressively becoming the standard of care in the treatment of many tumour types. Immunotherapy is bringing new hope to patients, but also a whole new spectrum of toxicities for healthcare practitioners to manage. Oncologists and specialists involved in the pluridisciplinary management of patients with cancer are increasingly confronted with the therapeutic challenge of treating patients with severe and refractory immune-related adverse events. In this Personal View, we summarise the therapeutic strategies that have been used to manage such toxicities resulting from immune checkpoint inhibitor treatment. On the basis of current knowledge about their pathogenesis, we discuss the use of new biological and non-biological immunosuppressive drugs to treat severe and steroid refractory immune-related adverse events. Depending on the immune infiltrate type that is predominant, we propose a treatment algorithm for personalised management that goes beyond typical corticosteroid use. We propose a so-called shut-off strategy that aims at inhibiting key inflammatory components involved in the pathophysiological processes of immune-related adverse events, and limits potential adverse effects of drug immunosuppression on tumour response. This approach develops on current guidelines and challenges the step-by-step increase approach to drug immunosuppression.

Diagnosis, monitoring, and management of adverse events from immune checkpoint inhibitor therapy

Immune checkpoint inhibitor therapy (icit) is now a standard of care for a variety of cancers in both the metastatic and adjuvant settings. As a result, an understanding of the timing, epidemiology, monitoring, diagnosis, and management of immune-related adverse events (iraes) associated with icit is imperative. This article reviews specific iraes by organ system, consolidating recommendations from multiple guidelines and incorporating data from case reports to highlight additional evolving therapeutic options for patients. Managing iraes requires early recognition, early intervention, and education of the patients and the multidisciplinary health care team alike. Given the durable responses observed with icit, and the irreversible nature of some of the iraes, further research into management of the sequelae of icit is required.

Clinical diagnosis and treatment of immune checkpoint inhibitor-associated adverse events in the digestive system

Immunotherapy for malignant tumors is a hot spot in current research and the treatment of cancer. The activation of programmed cell death receptor-1 (PD-1) and cytotoxic T lymphocyte-associated antigen 4 (CTLA)-4 relevant signaling pathway can inhibit the activation of T lymphocytes. Tumor cells can achieve immune escape by activating this signaling pathway. By inhibiting this signaling pathway, immune-checkpoint inhibitors (ICIs) activate T lymphocytes to clear the tumor cells. Therefore, the adverse effects of ICIs are mainly immune-related adverse events (irAEs). The digestive system, including the gastrointestinal tract and liver which are vital organs of digestion and absorption, metabolism and detoxification, as well as important immune-related organs, is the most commonly affected system of irAEs. This review explains the incidence, clinical features, diagnosis and treatment of liver and gastrointestinal adverse events in ICIs.

Immunotoxicity from checkpoint inhibitor therapy: clinical features and underlying mechanisms

Immune checkpoint inhibition with monoclonal antibodies is becoming increasingly commonplace in cancer medicine, having contributed to a widening of therapeutic options across oncological indications. Disruption of immune tolerance is the key mechanism of action of checkpoint inhibitors and although immune-related adverse events are a typical class effect of these compounds, the relationship between toxicity and response is not fully understood. Awareness and vigilance are paramount in recognizing potentially life-threatening toxicities and managing them in a timely manner. In this review article, we provide an overview of the clinical features, pathological findings and management principles of common immune-related toxicities, attempting to provide mechanistic insight into an increasingly common complication of cancer therapy.

[Supportive therapy and management of side effects in dermato-oncology]

In the context of supportive therapy, possible complaints which may be caused by the cancer itself, by the antitumoral therapy or by psychosocial concerns are considered. Due to the introduction of new anticancer drugs in dermato-oncology, clinicians are confronted with a novel spectrum of adverse events. There are a number of inflammatory, immune-mediated side effects caused by immunotherapies, which can affect virtually any organ. Targeted therapies also have specific side effects. Basically, the management of adverse events depends on their severity. Besides treatment breaks and dosage modifications, immunotherapy-related adverse events are treated with systemic immunosuppressants. Supportive symptomatic therapy is offered. The additional consideration of psychosocial problems can improve quality of life of cancer patients.

Pembrolizumab for anaplastic thyroid cancer: a case study

Blockade of the PD-1/PD-L1 pathway with targeted monoclonal antibodies has demonstrated encouraging anti-tumour activity in multiple cancer types. We present the case of a patient with BRAF-negative stage IVC anaplastic thyroid cancer (ATC) treated with the anti-PD-1 monoclonal antibody, pembrolizumab, following radiographic progression on chemoradiation. Blood samples were collected prior to and at four time points during treatment with pembrolizumab. Mass cytometry was used to determine expression of relevant biomarkers by peripheral blood mononuclear cells. Faecal samples were collected at baseline and 4 weeks following treatment initiation; taxonomic profiling using 16S ribosomal RNA (rRNA) gene sequencing was performed. Following treatment, a marked expansion in CD20⁺ B cell, CD16⁺ CD56^lo NK cell and CD45RO⁺ CCR7⁺ central memory CD4⁺ T-cell populations was observed in the peripheral blood. Proportions of cells expressing the co-receptors TIGIT, OX40 and CD86 also increased during treatment. A high abundance of bacteria of the order Bacteroidales, specifically from the Bacteroidaceae and Rikenellaceae families, was identified in the faecal microbiota. Moreover, the patient's microbiome was enriched in Clostridiales order members Ruminococcaceae, Veillonellaceae and Lachnospiraceae. Alpha diversity of the gut microbiome was significantly higher following initiation of checkpoint therapy as assessed by the Shannon and Simpson index. Our results suggest that treatment with pembrolizumab promotes expansion of T-, B- and NK cell populations in the peripheral blood at the time of tumour regression and have the potential to be implemented as predictive biomarkers in the context of checkpoint blockade therapy. Larger studies to confirm these findings are warranted.

Immune checkpoint inhibitors and cardiovascular toxicity

Immune checkpoint inhibitors are a new class of anticancer therapies that amplify T-cell-mediated immune responses against cancer cells. Immune checkpoint inhibitors have shown important benefits in phase 3 trials, and several agents have been approved for specific malignancies. Although adverse events from immune checkpoint inhibitors are a common occurrence, cardiotoxic effects are uncommon, but are often serious complications with a relatively high mortality. Most cardiotoxic effects appear to be inflammatory in nature. Clinical assessment of a combination of biomarkers, electrocardiography, cardiac imaging, and endomyocardial biopsy can be used to confirm a possible diagnosis. In this Review, we discuss the epidemiology of immune checkpoint inhibitor-mediated cardiotoxic effects, as well as their clinical presentation, subtypes, risk factors, pathophysiology, and clinical management, including the introduction of a new surveillance strategy.

Checkpoint Inhibitors

BACKGROUND

Treatment with checkpoint inhibitors such as anti-programmed death-1 (anti-PD-1), anti-PD-ligand 1 (anti-PD-L1), and anti-cytotoxic T-lymphocyte antigen-4 (anti-CTLA-4) antibodies can prolong the survival of cancer patients, but it also induces autoimmune side effects in 86-96% of patients by activating the immune system. In 17-59% of patients, these are severe or even life-threatening.

METHODS

This review is based on pertinent articles retrieved by a search in PubMed and on an evaluation of a side-effect registry.

RESULTS

Checkpoint-inhibitor-induced autoimmune side effects manifest themselves in all organ systems, most commonly as skin lesions (46-62%), autoimmune colitis (22-48%), autoimmune hepatitis (7-33%), and endocrinopathies (thyroiditis, hypophysitis, adrenalitis, diabetes mellitus; 12-34%). Rarer side effects include pneumonitis (3-8%), nephritis (1-7%), cardiac side effects including cardiomyositis (5%), and neurological side effects (1-5%). Severe (sometimes lethal) side effects arise in 17-21%, 20-28%, and 59% of patients undergoing anti-PD-1 and anti- CTLA-4 antibody treatment and the approved combination therapy, respectively. With proper monitoring, however, these side effects can be recognized early and, usually, treated with success. Endocrine side effects generally require long-term hormone substitution. Patients who have stopped taking checkpoint inhibitors because of side effects do not show a poorer response of their melanoma or shorter survival in comparison to patients who continue to take checkpoint inhibitors.

CONCLUSION

The complex management of checkpoint-inhibitor-induced side effects should be coordinated in experienced centers. The creation of an interdisciplinary "tox team" with designated experts for organ-specific side effects has proven useful. Prospective registry studies based on structured documentation of side effects in routine clinical practice are currently lacking and urgently needed.

The immune checkpoint CD96 defines a distinct lymphocyte phenotype and is highly expressed on tumor-infiltrating T cells

CD96 has recently been shown to be a potent immune checkpoint molecule in mice, but a similar role in humans is not known. In this study, we provide a detailed map of CD96 expression across human lymphocyte lineages, the kinetics of CD96 regulation on T-cell activation and co-expression with other conventional and emerging immune checkpoint molecules. We show that CD96 is predominantly expressed by T cells and has a unique lymphocyte expression profile. CD96^high T cells exhibited distinct effector functions on activation. Of note, CD96 expression was highly correlated with T-cell markers in primary and metastatic human tumors and was elevated on antigen-experienced T cells and tumor-infiltrating lymphocytes. Collectively, these data demonstrate that CD96 may be a promising immune checkpoint to enhance T-cell function against human cancer and infectious disease.

Immune Checkpoint Inhibitor-Associated Colitis and Hepatitis

Immune checkpoint inhibitors (ICPIs) are monoclonal antibodies that target downregulators of the anti-cancer immune response: cytotoxic T-lymphocyte antigen-4, programmed cell death protein-1, and its ligand PD-L1. ICPIs are now approved for the treatment of a wide array of malignancies, with rates of durable responses in the metastatic setting far exceeding what would be expected from conventional chemotherapy. ICPIs have also been associated with rare but serious immune-related adverse events due to over-activation of the immune system that can affect any organ, including the gastrointestinal tract and liver. As the use of ICPIs in oncology continues to increase, ICPI-associated colitis and hepatitis will be encountered frequently by gastroenterologists and hepatologists. This review will focus on the diagnosis and management of ICPI-associated colitis and hepatitis. We will also compare these ICPI-related toxicities with sporadic inflammatory bowel disease and autoimmune liver disease.

Combination with SGT-53 overcomes tumor resistance to a checkpoint inhibitor

The tumor suppressor p53 responds to genotoxic and oncogenic stresses by inducing cell cycle arrest and apoptosis. Recent studies suggest that p53 also participates in the regulation of cellular immune responses. Here, we have investigated the potential of p53 gene therapy to augment immune checkpoint inhibition by combining an anti-programmed cell death protein 1 (PD1) antibody with SGT-53, our investigational nanomedicine carrying a plasmid encoding human wild-type p53. In three syngeneic mouse tumor models examined including a breast cancer, a non-small cell lung carcinoma, and a glioblastoma, SGT-53 sensitized otherwise refractory tumors to anti-PD1 antibody. The involvement of p53 in enhancing anti-PD1 immunotherapy appears to be multifaceted, since SGT-53 treatment increased tumor immunogenicity, enhanced both innate and adaptive immune responses, and reduced tumor-induced immunosuppression in a 4T1 breast tumor model. In addition, SGT-53 alleviates a fatal xenogeneic hypersensitivity associated with the anti-PD1 antibody in this model. Our data suggest that restoring p53 function by SGT-53 is able to boost anti-tumor immunity to augment anti-PD1 therapy by sensitizing tumors otherwise insensitive to anti-PD1 immunotherapy while reducing immune-related adverse events.