Pathological characterization of nivolumab-related liver injury in a patient with glioblastoma

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.

Tumor-infiltrating CD8+ sub-populations in primary and recurrent glioblastoma: An in-silico study

Background

Glioblastoma multiforme (GBM) remains an incurable primary brain tumor. CD8+ tumor-infiltrating lymphocytes (TILs) can target malignant cells; however, their anti-tumoral immune responses mostly do not lead to GBM rejection in GBM patients. We profiled the sub-populations of tumor-infiltrating CD8+ T-cells, i.e., naïve, cytotoxic, and exhausted cells, in primary and recurrent GBM tissues and provided a blueprint for future precision-based GBM immunotherapy.

Method

We re-analyzed the raw data of single-cell RNA sequencing on the cells residing in the GBM microenvironment and leveraged tumor bulk RNA analyses to study the significance of CD8+ TILs sub-populations in primary and recurrent GBM. We investigated cell-cell interaction between exhausted CD8+ TILs and other immune cells residing in the primary and recurrent GBM microenvironments and profiled the expression changes following CD8+ TILs' transition from primary GBM to recurrent GBM.

Results

Exhausted CD8+ TILs are the majority of CD8+ TILs sub-populations in primary and recurrent GBM, and cytotoxic CD8+ TILs display decreased expression of inhibitory immune checkpoint (IC) molecules in the primary and recurrent GBM. In the primary and recurrent GBM microenvironment, exhausted CD8+ TILs interact most with tumor-infiltrating dendritic cells.

Conclusion

This study demonstrates the profiles of CD8+ TILs sub-populations in primary and recurrent GBM and provides a proof-of-concept for future precision-based GBM immunotherapy.

Liver Pathology Related to Onco-Therapeutic Agents

Oncotherapeutic agents can cause a wide range of liver injuries from elevated liver functions tests to fulminant liver failure. In this review, we emphasize a newer generation of drugs including immune checkpoint inhibitors, protein kinase inhibitors, monoclonal antibodies, and hormonal therapy. A few conventional chemotherapy agents are also discussed.

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.

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.

A Systematic Review on PD-1 Blockade and PD-1 Gene-Editing of CAR-T Cells for Glioma Therapy: From Deciphering to Personalized Medicine

Background

Programmed cell death protein 1 (PD-1) can attenuate chimeric antigen receptor-T (CAR-T) cell-mediated anti-tumoral immune responses. In this regard, co-administration of anti-PD-1 with CAR-T cells and PD-1 gene-editing of CAR-T cells have been suggested to disrupt this inhibitory axis. Herein, we aim to investigate the advantages and disadvantages of these two approaches and propose a novel strategy to ameliorate the prognosis of glioma patients.

Methods

Scopus, Embase, and Web of Science were systematically searched to obtain relevant peer-reviewed studies published before March 7, 2021. Then, the current study was conducted based on the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statements. The random-effect model was applied to evaluate the effect size of administrated agents on the survival of animal models bearing gliomas using RevMan version 5.4. The Cochran Q test and I2 were performed to assess the possible between-study heterogeneity. Egger's and Begg and Mazumdar's tests were performed to objectively assess potential asymmetry and publication bias using CMA version 2.

Results

Anti-PD-1 can substantially increase the survival of animal models on second-generation CAR-T cells. Also, PD-1 knockdown can remarkably prolong the survival of animal models on third-generation CAR-T cells. Regardless of the CAR-T generations, PD-1 gene-edited CAR-T cells can considerably enhance the survival of animal-bearing gliomas compared to the conventional CAR-T cells.

Conclusions

The single-cell sequencing of tumoral cells and cells residing in the tumor microenvironment can provide valuable insights into the patient-derived neoantigens and the expression profile of inhibitory immune checkpoint molecules in tumor bulk. Thus, single-cell sequencing-guided fourth-generation CAR-T cells can cover patient-derived neoantigens expressed in various subpopulations of tumoral cells and inhibit related inhibitory immune checkpoint molecules. The proposed approach can improve anti-tumoral immune responses, decrease the risk of immune-related adverse events, reduce the risk of glioma relapse, and address the vast inter-and intra-heterogeneity of gliomas.

Encouraging probiotics for the prevention and treatment of immune-related adverse events in novel immunotherapies against malignant glioma

Among the malignant tumors in the central nervous system (CNS), glioma is the most challenging tumor to the public society, which accounts for the majority of intracranial malignant tumors with impaired brain function. In general, conventional therapies are still unable to provide an effective cure. However, novel immunotherapies have changed the treatment scene giving patients a greater potential to attain long term survival, improved quality of life. Having shown favorable results in solid tumors, those therapies are now at a cancer research hotspot, which could even shrink the growth of glioma cells without causing severe complications. However, it is important to recognize that the therapy may be occasionally associated with noteworthy adverse action called immune-related adverse events (IRAEs) which have emerged as a potential limitation of the therapy. Multiple classes of mediators have been developed to enhance the ability of immune system to target malignant tumors including glioma but may also be associated with the IRAEs. In addition, it is probable that it would take long time after the therapy to exhibit severe immune-related disorders. Gut microbiota could play an integral role in optimal immune development and/or appropriate function for the cancer therapy, which is a vital component of the multidirectional communication between immune system, brain, and gut, also known as gut-brain-immune axis. Here, we show the potential effects of the gut-brain-immune axis based on an "engram theory" for the innovative treatment of IRAEs.

A Systematic Review of the Tumor-Infiltrating CD8+ T-Cells/PD-L1 Axis in High-Grade Glial Tumors: Toward Personalized Immuno-Oncology

Based on preclinical findings, programmed death-ligand 1 (PD-L1) can substantially attenuate CD8⁺ T-cell-mediated anti-tumoral immune responses. However, clinical studies have reported controversial results regarding the significance of the tumor-infiltrating CD8⁺ T-cells/PD-L1 axis on the clinical picture and the response rate of patients with high-grade glial tumors to anti-cancer therapies. Herein, we conducted a systematic review according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statements to clarify the clinical significance of the tumor-infiltrating CD8⁺ T-cells/PD-L1 axis and elucidate the impact of this axis on the response rate of affected patients to anti-cancer therapies. Indeed, a better understanding of the impact of this axis on the response rate of affected patients to anti-cancer therapies can provide valuable insights to address the futile response rate of immune checkpoint inhibitors in patients with high-grade glial tumors. For this purpose, we systematically searched Scopus, Web of Science, Embase, and PubMed to obtain peer-reviewed studies published before 1 January 2021. We have observed that PD-L1 overexpression can be associated with the inferior prognosis of glioblastoma patients who have not been exposed to chemo-radiotherapy. Besides, exposure to anti-cancer therapies, e.g., chemo-radiotherapy, can up-regulate inhibitory immune checkpoint molecules in tumor-infiltrating CD8⁺ T-cells. Therefore, unlike unexposed patients, increased tumor-infiltrating CD8⁺ T-cells in anti-cancer therapy-exposed tumoral tissues can be associated with the inferior prognosis of affected patients. Because various inhibitory immune checkpoints can regulate anti-tumoral immune responses, the single-cell sequencing of the cells residing in the tumor microenvironment can provide valuable insights into the expression patterns of inhibitory immune checkpoints in the tumor micromovement. Thus, administrating immune checkpoint inhibitors based on the data from the single-cell sequencing of these cells can increase patients’ response rates, decrease the risk of immune-related adverse events development, prevent immune-resistance development, and reduce the risk of tumor recurrence.

Efficacy of artificial liver support system in severe immune-associated hepatitis caused by camrelizumab: A case report and review of the literature

BACKGROUND

Immune checkpoint inhibitors (ICIs) can lead to immune-related hepatitis (IRH) and severe liver damage, which is life-threatening in the absence of specific treatment.

CASE SUMMARY

A 75-year-old man was admitted to our hospital complaining of loss of appetite, yellow urine, and abnormal liver function for the past 2 wk. Three months prior to admission, he was treated with two rounds of capecitabine in combination with camrelizumab for lymph node metastasis of esophageal cancer. Although liver function was normal before treatment, abnormal liver function appeared at week 5. Capecitabine and camrelizumab were discontinued. Ursodeoxycholic acid and methylprednisolone 40 mg daily were administered. Liver function continued to deteriorate. Prothrombin time and international normalized ratio were 19 s and 1.8, respectively. The patient was diagnosed with acute liver failure. A pathological analysis of liver biopsy indicated a strongly positive immunohistochemical staining of T8⁺ cells, thereby suggesting that drug-induced liver injury was related to IRH caused by camrelizumab. Subsequently, we performed sequential dual-molecule plasma adsorption system (DPMAS) treatment with plasma exchange (PE). After two rounds of treatment, the patient's appetite significantly improved, the yellow color of urine reduced, and liver function improved (total bilirubin level decreased) after five rounds of treatment. Liver function normalized 4 wk after discharge.

CONCLUSION

The use of sequential DPMAS with PE can reduce liver injury and systemic toxic reactions by clearing inflammatory mediators and harmful substances from blood, and regulate immune cell activity, which may be effective in the treatment of severe ICI-induced IRH.

A case report on severe nivolumab-induced adverse events similar to primary sclerosing cholangitis refractory to immunosuppressive therapy

INTRODUCTION

Immune checkpoint inhibitors (ICIs), particularly anti-PD-1 antibody, have dramatically changed cancer treatment; however, fatal immune-related adverse events (irAEs) can develop. Here, we describe a severe case of sclerosing cholangitis-like irAE. We report the use of 3 immunosuppressive agents that resulted in the death of the patient due to treatment inefficacy. According to a postmarketing study of nivolumab, the frequency of ICI-related sclerosing cholangitis is 0.27% and that of ICI-related cholangitis is 0.20%. There have been 4 case reports of sclerosing cholangitis-like irAE, with imaging findings, including typical intrahepatic bile duct beaded constriction in primary sclerosing cholangitis. Treatment starts with prednisolone and is combined with an immunosuppressant in refractory cases. There are no reports of severe cases that ultimately led to death.

PATIENTS CONCERNS

The patient is a 64-year-old male with Stage IV squamous cell lung carcinoma; he was hospitalized with abdominal pain and elevation of aspartate transaminase and alanine transaminase, approximately 4 months after ICI administration was suspended. This occurred because the patient treated with nivolumab as the second-line chemotherapy and developed type 1 diabetes mellitus after 11 courses.

DIAGNOSIS

A grade 3 increase in bilirubin was observed and he was diagnosed with sclerosing cholangitis, based on magnetic resonance cholangiopancreatography imaging and pathological findings of the liver and bile duct.

INTERVENTIONS

Prednisolone, mycophenolate mofetil, and tacrolimus combination therapy was administered.

OUTCOMES

The treatment was difficult and failed. He died from liver failure 8 months after diagnosis. In this case, hepatitis and cholangitis, mainly alanine transaminase-dominant liver disorder, developed in the early stages of irAEs. Although he showed some improvement after prednisolone administration, bilirubin levels began rising again, and sclerosing cholangitis did not improve even with the use of 3 immunosuppressive agents recommended by the ESMO Clinical Practice Guidelines for immune-related hepatotoxicity management. Although the antitumor effect showed a complete response, liver failure led to death.

CONCLUSION

This is the first case report on the ineffectiveness of triple immunosuppressant combination therapy recommended by the guidelines for immune-related hepatotoxicity. It is necessary to develop more appropriate treatment for severe sclerosing cholangitis-like irAE based on the robust evidence.

Upregulating Aggregation-Induced-Emission Nanoparticles with Blood-Tumor-Barrier Permeability for Precise Photothermal Eradication of Brain Tumors and Induction of Local Immune Responses

Compared to other tumors, glioblastoma (GBM) is extremely difficult to treat. Recently, photothermal therapy (PTT) has demonstrated advanced therapeutic efficacy; however, because of the relatively low tissue-penetration efficiency of laser light, its application in deep-seated tumors remains challenging. Herein, bradykinin (BK) aggregation-induced-emission nanoparticles (BK@AIE NPs) are synthesized; these offer selective penetration through the blood-tumor barrier (BTB) and strong absorbance in the near-infrared region (NIR). The BK ligand can prompt BTB adenosine receptor activation, which enhances transportation and accumulation inside tumors, as confirmed by T1 -weighted magnetic resonance and fluorescence imaging. The BK@AIE NPs exhibit high photothermal conversion efficiency under 980 nm NIR laser irradiation, facilitating the treatment of deep-seated tumors. Tumor progression can be effectively inhibited to extend the survival span of mice after spatiotemporal PTT. NIR irradiation can eradicate tumor tissues and release tumor-associated antigens. It is observed that the PTT treatment of GBM-bearing mice activates natural killer cells, CD3+ T cells, CD8+ T cells, and M1 macrophages in the GBM area, increasing the therapeutic efficacy. This study demonstrates that NIR-assisted BK@AIE NPs represent a promising strategy for the improved systematic elimination of GBMs and the activation of local brain immune privilege.

Fatal immune-related hepatitis with intrahepatic cholestasis and pneumonia associated with camrelizumab: A case report and literature review

Camrelizumab (SHR-1210), a human monoclonal antibody against programmed death receptor 1 (PD-1), blocks the binding of PD-1 to PD-L1, consequently inhibiting immune system evasion by tumor cells. A 65-year-old man underwent radical esophagectomy 5 months ago following the diagnosis of esophageal cancer by gastroscopy. Approximately 40 days later, capecitabine was administered at a dosage of 1.5 g Po bid for 14 days, and anti-PD-1 (camrelizumab 200 mg) was administered twice. Around 20 days later, abnormal liver function was detected. He received a diagnosis of drug-induced liver injury. Chest computed tomography scanning revealed interstitial inflammatory lesions in both lower lungs. Liver biopsy revealed immune injury with ductopenia. Therefore, the diagnosis was revised as immune-related pneumonia and hepatitis associated with camrelizumab. The treatment regimen of methylprednisolone was adjusted to 40 mg/day and gradually increased to 80 mg/day. Mycophenolate mofetil was administered at a dose of 2 g/day. Consequently, chest tightness and shortness of breath resolved, and pulmonary inflammation improved. However, jaundice did not improve and continued to exacerbate. The last measured prothrombin time was 41 s, prothrombin activity was 19%, and the international normalized ratio was 4.03. The cause of death was diagnosed as liver failure, cardiopulmonary failure, and septic shock.

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.

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.

Histologic patterns of liver injury induced by anti-PD-1 therapy

BACKGROUND

Nivolumab and pembrolizumab-two monoclonal antibodies that block human programmed cell death-1 (PD-1)-have been successfully used to treat patients with multiple advanced malignancies. The histologic patterns of hepatic toxicity induced by anti-PD-1 treatment have not been well studied and the aim of this study was to explore them.

METHODS

Eight patients with advanced malignancies who were treated with either nivolumab or pembrolizumab were identified from five institutions. These patients had no history of underlying liver disease and a viral hepatitis panel was negative in all patients.

RESULTS

Seven of eight patients exhibited mild to moderate gastrointestinal symptoms such as abdominal pain, fatigue, nausea, vomiting, and jaundice after anti-PD-1 treatment. Significant elevations in liver-chemistry tests were detected in all patients. Six cases (6/8) demonstrated an acute lobular hepatitis pattern of histologic injury. The remaining two cases showed different histologic patterns of injury: steatohepatitis with mild cholestasis (1/8) and pure acute cholestatic injury (1/8). No case showed typical features of autoimmune hepatitis. The liver function recovered in all eight cases after cessation of anti-PD-1 agents and with immunosuppressive therapy.

CONCLUSIONS

Our study suggests that screening patients for abnormal liver-function tests prior to anti-PD-1 therapy as well as periodic monitoring of liver-function tests are necessary to prevent severe liver injury. Rather than causing classical autoimmune hepatitis, PD-1 inhibitors appear to produce an immune-mediated nonspecific acute hepatitis. Drug cessation, without steroid therapy, may therefore be sufficient in some patients.

Impact of the gut microbiota on immune checkpoint inhibitor-associated toxicities

Immune checkpoint inhibitors (ICIs) have transformed the treatment of patients with advanced cancers. However, the majority of patients do not respond or develop early progressive disease. A substantial number also develop immune-mediated toxicities that may lead to early treatment discontinuation. Gastrointestinal toxicities in the form of diarrhea and colitis are common and may resemble that observed in patients with inflammatory bowel disease (IBD). Alterations in the gut microbiota are thought to play an important role in mediating the intestinal inflammation that is associated with immune-mediated colitis. In this review, the authors' objective is to provide an overview of the gastrointestinal and hepatic toxicities that can be seen with ICIs and discuss the interactions between gut microbiota and the immune response. The authors also highlight the potential role for fecal microbial transfer (FMT) as an approach to improve therapeutic efficacy and decrease toxicity.

Adverse Effects of Immune Checkpoint Inhibitors (Programmed Death-1 Inhibitors and Cytotoxic T-Lymphocyte-Associated Protein-4 Inhibitors): Results of a Retrospective Study

In recent years the use of immunomodulating therapy to treat various cancers has been on the rise. Three checkpoint inhibitors have been approved by the Food and Drug Administration (ipilimumab, pembrolizumab and nivolumab). The use of these drugs comes with serious adverse events related to excessive immune activation, collectively known as immune-related adverse events (irAEs). We conducted a system-based review of 139 case reports/case series that have described these adverse events between January 2016 and April 2018, found in the PubMed database. There was a broad spectrum of presentations, doses and checkpoint inhibitors used. The most common check point inhibitor observed in our literature review was nivolumab. The most common adverse effects encountered were colitis (14/139), hepatitis (11/139), adrenocorticotropic hormone insufficiency (12/139), hypothyroidism (7/139), type 1 diabetes (22/139), acute kidney injury (16/139) and myocarditis (10/139). The treatment most commonly consisted of cessation of the immune checkpoint inhibitor, initiation of steroids and supportive therapy. This approach provided a complete resolution in a majority of cases; however, there were many that developed long-term adverse events with deaths reported in a few cases. The endocrine system was the mostly commonly affected with the development of type 1 diabetes mellitus or diabetic ketoacidosis being the most frequently reported adverse events. While immunomodulating therapy is a significant advance in the management of various malignancies, it is capable of serious adverse effects. Because the majority of the cases developed pancreatic dysfunction within five cycles of therapy, in addition to the evaluation of other systems, pancreatic function should be closely monitored to minimize adverse impact on patients.

Management of immune-related adverse events resulting from immune checkpoint blockade

Immune checkpoint inhibitors (ICI) are now a standard of care in the treatment of many cancers leading to durable responses in patients with metastatic disease. These agents are generally well tolerated but may lead to the occurrence of immune-related adverse events (irAEs). As any organ may be affected, clinicians should be aware of the broad range of clinical manifestations and symptoms and keep in mind that toxicities may occur late, at any point along a patient's treatment course. Although the most common irAEs are rarely severe, some of them may be associated with great morbidity and even become life-threatening. The rate of occurrence, type and severity of irAEs may vary with the type of ICI; thus, grade 3 and 4 irAEs are reported in more than 55% of patients treated with the combination of ipilimumab 3 mg/kg and nivolumab 1 mg/kg. Area covered: This review presents the management of irAEs resulting from checkpoint blockade, with a focus on rare irAEs. Expert commentary: With the development of immuno-oncology and the expanding role of ICI, physicians have learnt to diagnose and treat most of the irAEs that can occur. This review provides an overview of current guidelines, previously published studies and our multidisciplinary team based practices.

The Prognostic and Therapeutic Value of PD-L1 in Glioma

Glioma is the most common type of primary brain tumors. After standard treatment regimen (surgical section, radiotherapy and chemotherapy), the average survival time remains merely around 14 months for glioblastoma (grade IV glioma). Recent immune therapy targeting to the immune inhibitory checkpoint axis, i.e., programmed cell death protein 1 (PD-1) and its ligand PD-L1 (i.e., CD274 or B7-H1), has achieved breakthrough in many cancers but still not in glioma. PD-L1 is considered a major prognostic biomarker for immune therapy in many cancers, with anti-PD-1 or anti-PD-L1 antibodies being used. However, the expression and subcellular distribution of PD-L1 in glioma cells exhibits great variance in different studies, severely impairing PD-L1's value as therapeutic and prognostic biomarker in glioma. The role of PD-L1 in modulating immune therapy is complicated. In addition, endogenous PD-L1 plays tumorigenic roles in glioma development. In this review, we summarize PD-L1 mRNA expression and protein levels detected by using different methods and antibodies in human glioma tissues in all literatures, and we evaluate the prognostic value of PD-L1 in glioma. We also summarize the relationships between PD-L1 and immune cell infiltration in glioma. The mechanisms regulating PD-L1 expression and the oncogenic roles of endogenous PD-L1 are discussed. Further, the therapeutic results of using anti-PD-1/PD-L1 antibodies or PD-L1 knockdown are summarized and evaluated. In summary, current results support that PD-L1 is not only a prognostic biomarker of immune therapy, but also a potential therapeutic target for glioma.

Liver damage related to immune checkpoint inhibitors

Recently, immune checkpoint inhibitors are becoming one of the key agents of systemic treatment of cancer. The anti-cancer mechanism of this type of agent is totally different from that of conventional therapies; blockade of regulatory receptors and ligand of immune checkpoint molecules arose anti-tumor immunity with durable response. However, owing to its unique action to host immune system, immune checkpoint inhibitors sometimes induce immune-related adverse events (irAEs) which has not been observed for conventional chemotherapies. It has been reported that irAEs are manageable by discontinuation of immune checkpoint inhibitors and corticosteroid. However, severe irAEs might lead to the unsuccessful management of cancer treatment. It is conceivable that irAEs during the treatment of immune checkpoint blockade might mimic the autoimmune disease of the specific organ, such as autoimmune hepatitis (AIH). However, detail of the pathogenesis of irAEs has not been well estimated. In this review, we specially focused on this important issue and discussed the liver toxicity of this type of agent in the context of comparison of clinical and pathological findings of liver damage related to irAEs and AIH.

[Hepatic and digestive adverse events of immune checkpoint inhibitors (anti-CTLA-4 and, anti-PD-1/PD-L1): A clinico-pathological review]

Immune checkpoint inhibitors (anti-CTLA-4 and anti-PD-1/PD-L1) have recently revolutionized anti-cancer therapy and are nowadays used in different metastatic cancers. These treatments may induce immune-related adverse events which frequently involve the digestive tract and, to a less extent the liver. The tissular injuries, which are still poorly characterized from a morphological and physiopathological point of view, may lead on one side to the interruption of a life-saving treatment and on the other side to the development of severe complications, if not death. Therefore, it is crucial to diagnose as early as possible and treat these digestive and hepatic adverse effects in an optimal way. This article aims to describe the clinical and pathological presentations of digestive and hepatic adverse events induced by these immunotherapies.

Characterization of liver injury induced by cancer immunotherapy using immune checkpoint inhibitors

BACKGROUND & AIMS

Immunotherapy for metastatic cancer can be complicated by the onset of hepatic immune-related adverse events (IRAEs). This study compared hepatic IRAEs associated with anti-programmed cell death protein 1 (PD-1)/PD ligand 1 (PD-L1) and anti-cytotoxic T lymphocyte antigen 4 (CTLA-4) monoclonal antibodies (mAbs).

METHODS

Among 536 patients treated with anti-PD-1/PD-L1 or CTLA-4 immunotherapies, 19 (3.5%) were referred to the liver unit for grade ≥3 hepatitis. Of these patients, nine had received anti-PD-1/PD-L1 and seven had received anti-CTLA-4 mAbs, in monotherapy or in combination with anti-PD-1. Liver investigations were undertaken in these 16 patients, including viral assays, autoimmune tests and liver biopsy, histological review, and immunostaining of liver specimens.

RESULTS

In the 16 patients included in this study, median age was 63 (range 33-84) years, and nine (56%) were female. Time between therapy initiation and hepatitis was five (range, 1-49) weeks and median number of immunotherapy injections was two (range, 1-36). No patients developed hepatic failure. Histology related to anti-CTLA-4 mAbs demonstrated granulomatous hepatitis including fibrin ring granulomas and central vein endotheliitis. Histology related to anti-PD-1/PD-L1 mAbs was characterised by lobular hepatitis. The management of hepatic IRAEs was tailored according to the severity of both the biology and histology of liver injury: six patients improved spontaneously; seven received oral corticosteroids at 0.5-1 mg/kg/day; two were maintained on 0.2 mg/kg/day corticosteroids; and one patient required pulses and 2.5 mg/kg/day of corticosteroids, and the addition of a second immunosuppressive drug. In three patients, immunotherapy was reintroduced without recurrence of liver dysfunction.

CONCLUSIONS

Acute hepatitis resulting from immunotherapy for metastatic cancer is rare (3.5%) and, in most cases, not severe. Histological assessment can distinguish between anti-PD-1/PD-L1 and anti-CTLA-4 mAb toxicity. The severity of liver injury is helpful for tailoring patient management, which does not require systematic corticosteroid administration.

LAY SUMMARY

Immunotherapy for metastatic cancer can be complicated by immune-related adverse events in the liver. In patients receiving immunotherapy for metastatic cancer who develop immune-mediated hepatitis, liver biopsy is helpful for the diagnosis and evaluation of the severity of liver injury. This study demonstrates the need for patient-oriented management, which could eventually avoid unnecessary systemic corticosteroid treatment.

Hepatotoxicity of immune checkpoint inhibitors: a histology study of seven cases in comparison with autoimmune hepatitis and idiosyncratic drug-induced liver injury

The adverse effects of immune checkpoint inhibitors in various organs may be attributed to immune-mediated processes triggered by disrupted self-tolerance; however, it remains unclear whether they are similar or dissimilar to classic organ-specific autoimmune diseases. The present study aimed to compare clinicopathologic features between checkpoint inhibitor-induced liver injury and acutely presenting autoimmune hepatitis or idiosyncratic drug-induced liver injury. Seven patients treated with nivolumab (n = 5) or ipilimumab (n = 2) presented with liver dysfunction a median of 41 days (range 21-120) after the initiation of immunotherapy. All patients had elevated liver enzymes, whereas hyper-bilirubinemia was less common. None of the patients had antinuclear antibodies or IgG elevations. Stopping the immunotherapy and additional immunosuppression with corticosteroids normalized or decreased liver enzymes in all patients treated. Histologically, all biopsies showed predominantly lobular hepatitis with milder portal inflammation. Centrilobular confluent necrosis and plasmacytosis were observed in a single case, and were markedly less common and milder than those in autoimmune hepatitis (p = 0.017 and p < 0.001, respectively). Bile duct injury, micro-abscesses, and extramedullary hematopoiesis were also found in one case each. Immunostaining revealed the presence of large numbers of CD3+ and CD8+ lymphocytes, whereas CD20+ B cells and CD4+ T cells were fewer in checkpoint inhibitor-induced liver injury than in autoimmune hepatitis or drug-induced liver injury. In conclusion, liver injury caused by cancer immunotherapy shares some features with injury of autoimmune hepatitis; however, there are obvious differences between the two conditions. Checkpoint inhibitor-induced liver injury may represent an immune-mediated, less zone-selective hepatocyte necrosis not requiring the strong activation of helper T cells and immunoglobulin production.

Immune checkpoint inhibitor-induced gastrointestinal and hepatic injury: pathologists' perspective

Immune checkpoint inhibitors (CPIs) are a relatively new class of 'miracle' dugs that have revolutionised the treatment and prognosis of some advanced-stage malignancies, and have increased the survival rates significantly. This class of drugs includes cytotoxic T lymphocyte antigen-4 inhibitors such as ipilimumab; programmed cell death protein-1 inhibitors such as nivolumab, pembrolizumab and avelumab; and programmed cell death protein ligand-1 inhibitors such as atezolizumab. These drugs stimulate the immune system by blocking the coinhibitory receptors on the T cells and lead to antitumoural response. However, a flip side of these novel drugs is immune-related adverse events (irAEs), secondary to immune-mediated process due to disrupted self-tolerance. The irAEs in the gastrointestinal (GI) tract/liver may result in diarrhoea, colitis or hepatitis. An accurate diagnosis of CPI-induced colitis and/or hepatitis is essential for optimal patient management. As we anticipate greater use of these drugs in the future given the significant clinical response, pathologists need to be aware of the spectrum of histological findings that may be encountered in GI and/or liver biopsies received from these patients, as well as differentiate them from its histopathological mimics. This present review discusses the clinical features, detailed histopathological features, management and the differential diagnosis of the luminal GI and hepatic irAEs that may be encountered secondary to CPI therapy.

Late-onset nivolumab-mediated pneumonitis in a patient with melanoma and multiple immune-related adverse events

Immune-related adverse effects (AEs) of PD-1 inhibitors can affect almost every organ, but the skin, intestine, lung, eye, and liver are the most commonly affected organs. Here, we present the case of a 62-year-old female patient with stage IIIc melanoma treated with nivolumab in an adjuvant setting who sequentially developed hyperthyroidism, hypothyroidism, acute hepatitis, and pneumonitis. Six months before the emergence of pneumonitis, the patient had discontinued treatment with nivolumab because of acute hepatitis. Information on pneumonitis after nivolumab discontinuation in the literature is scarce, whereas most of the cases emerge during the first 2.5 months of treatment. Patients with multiple immune-related AEs comprise a group of special interest as the identification of factors affecting the susceptibility of patients to immune-related AEs of PD-1 inhibitors may lead to a more rational use of these drugs. Human leukocyte antigen haplotype and Fcγ receptor polymorphisms are possible targets of the relevant research.

Clinical features, predictive correlates, and pathophysiology of immune-related adverse events in immune checkpoint inhibitor treatments in cancer: a short review

Identification and characterization of T-cell regulatory mechanisms, or checkpoints, have led to a wave of drug development aimed at inhibiting these targets to "remove the brakes" of the immune system. This class of anticancer therapeutics, termed immune checkpoint inhibitors (ICIs), has harnessed the potential of the body's own immune system to recognize cancerous cells and selectively eliminate them, in some cases with alarming success. This new breakthrough, however, has not been without its drawbacks. Immune-related adverse events (irAEs) are adverse events encountered during treatment with ICIs that are thought to be mediated through the patient's immune system which can manifest with a variety of symptoms which often resemble autoimmunity. These events range widely in presentation and severity and are reported frequently. Here, we will discuss a large selection of case reports in order to inform the clinician, laboratorian, and researcher of the scope of organ systems affected, the severity of the conditions being encountered, and the responses of these events to treatment, as well as explore the use of ICIs in the setting of preexisting autoimmunity. We will also consider the ability to detect autoantibodies before and during irAEs as well as the correlations that irAEs have with clinical outcomes. Finally, we will conclude by exploring the possibility that two distinct pathways may be contributing to the phenomenon of irAEs within this class of drugs, and the role that this might play in future research and clinical practice.