Fibrin Ring Granulomas in Checkpoint Inhibitor-induced Hepatitis. Am J Surg Pathol. 2017;41:134-137. [PMID: 27792061 DOI: 10.1097/pas.0000000000000759]

Granulomatous liver diseases

A granuloma is a discrete collection of activated macrophages and other inflammatory cells. Hepatic granulomas can be a manifestation of localized liver disease or be a part of a systemic process, usually infectious or autoimmune. A liver biopsy is required for the detection and evaluation of granulomatous liver diseases. The prevalence of granulomas on liver biopsy varies from 1% to 15%. They may be an incidental finding in an asymptomatic individual, or they may represent granulomatous hepatitis with potential to progress to liver failure, or in chronic disease, to cirrhosis. This review focuses on pathogenesis, histological features of granulomatous liver diseases, and most common etiologies, knowledge that is essential for timely diagnosis and intervention.

Delayed immune-related hepatitis after 24 months of pembrolizumab treatment: a case report and literature review

Immune checkpoint inhibitors targeting the programmed cell death protein 1 (PD-1) pathway have revolutionized cancer immunotherapy by enhancing the immune system's ability to combat cancer cells. However, this innovative approach comes with a distinctive set of challenges, as these therapies can lead to immune-related adverse events (irAEs) due to their mechanism of action. The most common irAEs involve the skin, gastrointestinal tract, liver, endocrine system, and lungs. These events can range from mild skin rashes to severe colitis, pneumonitis, or even autoimmune organ damage. These adverse effects usually appear with an average of 5-15 weeks from the start of treatment depending on the affected organ. This article presents a case report of a delayed related-mediated hepatitis, after 24 months of treatment with pembrolizumab and almost 3 months after its termination, and a review of the scientific literature on cases of delayed immune-related hepatitis caused by anti-PD1. This case highlights the importance of monitoring patients treated with immune checkpoint inhibitors after cessation as a growing number of patients stop treatment due to achieving durable responses.

Morphology of immune-mediated hepatitis: A comparison between immune checkpoint inhibitor therapy and combined immune checkpoint inhibitor/anti-angiogenic therapy

BACKGROUND

The combination of immune checkpoint inhibitors (ICIs) with anti-angiogenic drugs has shown promising anticancer effects. However, ICIs can trigger immune-mediated hepatitis (IMH). We aimed to clarify whether the combined use of anti-angiogenic drugs and ICIs would increase the severity of IMH.

METHODS

One hundred IMH patients (ICI monotherapy vs. ICI plus anti-angiogenic therapy 30 vs. 70) were retrospectively enrolled. Clinicopathological parameters were compared between the two groups.

RESULTS

IMH mainly showed variable degrees of panlobular hepatitis (84 %), while some cases presented mixed cholangio-hepatitic (14 %) or cholangitic (2 %) pattern. The incidence of moderate-severe injury was not significantly different between the two groups (combination vs. monotherapy 38.6 % vs. 20.0 %, p = 0.109). Specifically, the rates of marked lobular injury and portal inflammation were higher in the combination group than in the monotherapy cohort (p < 0.005), while the frequencies of interface hepatitis, bile duct injury, histiocytosis aggregates, and endothelialitis were comparable between the two groups (p > 0.05). Compared to mild IMH cases, severe IMH cases showed higher immunostaining expression levels of PD-L1 (60.7 % vs. 19.4 %, p < 0.0001). Treatments and outcomes of IMH were not significantly different between the two groups (p > 0.05).

CONCLUSIONS

Compared to ICI monotherapy, the administration of anti-angiogenic drugs in combination with ICIs was not associated with increased hepatotoxicity.

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.

Gastrointestinal and Hepatobiliary Immune-related Adverse Events: A Histopathologic Review

Immune checkpoint inhibitors have been increasingly used to treat various malignant neoplasms. Despite their superior efficacy in treating certain ones, their global immune-activation effect leads to systemic side effects, referred to as immune-related adverse events. Immune-related adverse events affect a variety of organs, including the skin, gastrointestinal, hepatobiliary, and endocrine organs. Gastrointestinal tract immune-related adverse events present with a wide range of symptoms with variable severity, which may lead to treatment interruption and administration of immunosuppression therapy in many cases. Histopathologic changes are diverse, overlapping with many other conditions. Therefore, recognizing these changes is crucial in diagnosing immune-related adverse events. This review discusses the pathologic manifestations of gastrointestinal immune-related adverse events and discusses the primary differential diagnoses.

Immune-checkpoint inhibitor-associated grade 3 hepatotoxicity managed with enteric-coated budesonide monotherapy: A case report

RATIONALE

The introduction of immune-checkpoint inhibitors (ICPI) in recent years has changed the natural course of many neoplasms. However, patients receiving these medications may present immune-mediated adverse events; management includes temporary or permanent cessation of treatment and corticosteroids, occasionally combined with other immunomodulators. Such immunosuppression, however, also has numerous adverse events and even if it is effective in controlling toxicity, it delays immunotherapy reinitiation, as current evidence requires dose tapering to ≤10 mg prednisolone equivalent before rechallenge. Enteric-coated budesonide is a corticosteroid formulation acting primarily to the intestine and liver, as a result of its extensive first-pass hepatic metabolism.

PATIENT CONCERNS

A 76-year-old woman treated with ipilimumab for metastatic melanoma presented with abdominal pain, vomiting, and diarrhea for at least the previous 4 days. Laboratory tests, among others, revealed elevated aminotransferases and C-reactive protein. During hospitalization, the patient also developed fever.

DIAGNOSIS

The patient, after excluding alternative causes of aminotransferase elevation, was diagnosed with grade 3 ipilimumab-associated hepatotoxicity.

INTERVENTIONS

Budesonide monotherapy was administered; initial daily dose was 12 mg.

OUTCOMES

Fever subsided after the first dose of budesonide. Aminotransferases returned to normal-near normal approximately 1 month after the first dose of budesonide. After this point, daily dose was reduced by 3 mg every 2 weeks, with no clinical or biochemical relapse.

CONCLUSIONS

This case of ICPI hepatitis is, to our knowledge, the first in the literature managed with budesonide monotherapy. Therefore, budesonide may be a potentially attractive option for the management of ICPI-associated liver injury in cases where corticosteroid treatment is necessary due to its safety profile and the potential advantage of faster immunotherapy rechallenge in selected patients without requiring dose tapering, in contrast to systemically acting corticosteroids. Clinical trials should be conducted in the future in order to validate or refute these findings.

Gastrointestinal and Hepatobiliary Immune-related Adverse Events: A Histopathologic Review

Immune checkpoint inhibitors have been increasingly used to treat various malignant neoplasms. Despite their superior efficacy in treating certain ones, their global immune-activation effect leads to systemic side effects, referred to as immune-related adverse events. Immune-related adverse events affect a variety of organs, including the skin, gastrointestinal, hepatobiliary, and endocrine organs. Gastrointestinal tract immune-related adverse events present with a wide range of symptoms with variable severity, which may lead to treatment interruption and administration of immunosuppression therapy in many cases. Histopathologic changes are diverse, overlapping with many other conditions. Therefore, recognizing these changes is crucial in diagnosing immune-related adverse events. This review discusses the pathologic manifestations of gastrointestinal immune-related adverse events and discusses the primary differential diagnoses.

The Role of Myeloid Cells in Hepatotoxicity Related to Cancer Immunotherapy

Drug-related hepatotoxicity is an emerging clinical challenge with the widening use of immunotherapeutic agents in the field of oncology. This is an important complication to consider as more immune oncological targets are being identified to show promising results in clinical trials. The application of these therapeutics may be complicated by the development of immune-related adverse events (irAEs), a serious limitation often requiring high-dose immunosuppression and discontinuation of cancer therapy. Hepatoxicity presents one of the most frequently encountered irAEs and a better understanding of the underlying mechanism is crucial for the development of alternative therapeutic interventions. As a novel drug side effect, the immunopathogenesis of the condition is not completely understood. In the liver, myeloid cells play a central role in the maintenance of homeostasis and promotion of inflammation. Recent research has identified myeloid cells to be associated with hepatic adverse events of various immune modulatory monoclonal antibodies. In this review article, we provide an overview of the role of myeloid cells in the immune pathogenesis during hepatoxicity related to cancer immunotherapies and highlight potential treatment options.

Immune Checkpoint Inhibitors Induced Hepatotoxicity; Gastroenterologists' Perspectives

BACKGROUND: Immune checkpoint inhibitors (ICIs) have promising clinical activity and are essential medications for patients with several malignancies. However, by deranging the immune system, these novel agents could lead to immune-related adverse events (IRAEs). Hepatotoxicity with checkpoint inhibitors usually results in acute hepatitis or drug-induced liver injury. METHODS: This review article discusses the recent clinical evidence available regarding checkpoint inhibitor-induced hepatitis and reviews an approach to their diagnosis and management. CONCLUSION: ICIs have improved patients' outcomes with different forms of malignancy; however, ICIs-related liver damage is a clinically significant entity in these patients. All patients should be monitored carefully for IRAEs while undergoing treatment with ICIs.

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.

Steatosis, Steatohepatitis and Cancer Immunotherapy: An Intricate Story

Immune checkpoint inhibitors represent one of the most significant recent advances in clinical oncology, since they dramatically improved the prognosis of deadly cancers such as melanomas and lung cancer. Treatment with these drugs may be complicated by the occurrence of clinically-relevant adverse drug reactions, most of which are immune-mediated, such as pneumonitis, colitis, endocrinopathies, nephritis, Stevens Johnson syndrome and toxic epidermal necrolysis. Drug-induced steatosis and steatohepatitis are not included among the typical forms of cancer immunotherapy-induced liver toxicity, which, instead, usually occurs as a panlobular hepatitis with prominent lymphocytic infiltrates. Nonetheless, non-alcoholic fatty liver disease is a risk factor for immunotherapy-induced hepatitis, and steatosis and steatohepatitis are frequently observed in this condition. In the present review we discuss how these pathology findings could be explained in the context of current models suggesting immune-mediated pathogenesis for steatohepatitis. We also review evidence suggesting that in patients with hepatocellular carcinoma, the presence of steatosis or steatohepatitis could predict a poor therapeutic response to these agents. How these findings could fit with immune-mediated mechanisms of these liver diseases will also be discussed.

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.

Pathologic Manifestations of Gastrointestinal and Hepatobiliary Injury in Immune Checkpoint Inhibitor Therapy

CONTEXT.—

Immune checkpoint inhibitors (CPIs), including cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors and the programmed death receptor-1 (PD-1)/programmed death ligand-1 (PD-L1) inhibitors, are being increasingly used for treating many advanced malignancies. However, CPI therapy is also associated with gastrointestinal and hepatobiliary adverse effects.

OBJECTIVES.—

To review the adverse effects of CPI therapy on the gastrointestinal tract and hepatobiliary system. To describe histopathologic patterns and discuss differential diagnostic considerations in the diagnosis of CPI injuries.

DATA SOURCES.—

Published peer-reviewed literature in the English language and personal experience in the diagnosis of CPI injuries.

CONCLUSIONS.—

The pathologic manifestations of CPI therapy-induced gastrointestinal and hepatobiliary injury are broad. The patterns of esophageal CPI injury include lymphocytic inflammation and ulcerative esophagitis, while those of gastric injury include chronic active gastritis, lymphocytic gastritis, focal enhancing gastritis, and periglandular inflammation. The duodenal injury may present as duodenitis with villous blunting and granulomas. We also noticed active colitis, microscopic colitis, chronic active colitis, increased apoptosis, ischemic colitis, and nonspecific inflammatory reactive changes in colonic injuries. The reported histologic features of hepatobiliary injuries are panlobular hepatitis, centrilobular necrosis, portal inflammation with bile duct injury, steatosis, nodular regenerative hyperplasia, and secondary sclerosing cholangitis. In summary, we discuss the pathologic features and differential diagnosis of CPI therapy-induced gastrointestinal and hepatobiliary injury. Recognition of CPI injury is important to determine the proper management that often includes cessation of CPI therapy, and administration of steroids or other immunosuppressive agents, based on severity of injury.

Histopathology of Gastrointestinal Immune-related Adverse Events: A Practical Review for the Practicing Pathologist

Immune checkpoint inhibitors target checkpoint proteins with the goal of reinvigorating the host immune system and thus restoring antitumor response. With the dramatic increase in the use of checkpoint inhibitors for cancer treatment, surgical pathologists have assumed a major role in predicting the therapeutic efficacy (score based on programmed cell death ligand 1 immunohistochemistry and mismatch repair protein loss) as well as diagnosing the complications associated with these medications. Immune-related adverse events (irAEs) manifest as histologic changes seen in both the upper and lower gastrointestinal tract, and when viewed in isolation, may be morphologically indistinguishable from a wide range of diseases including infections, celiac disease, and inflammatory bowel disease, among others. Evaluation of biopsies from both the upper and lower gastrointestinal tract can aid in the distinction of gastrointestinal irAEs from their mimics. In the liver, the histologic changes of hepatic irAEs overlap with de novo diseases associated with hepatitic and cholangitic patterns of injury. The diagnosis of irAEs requires communication and collaboration from the pathologist, oncologist, and gastroenterologist. This review provides a background framework and illustrates the histologic features and differential diagnosis of gastrointestinal and hepatic irAEs.

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.

Extending the conversation over the immune-related hepatotoxicity: author response to Dr. Gauci et al

Immune-related hepatotoxicity (IRH) remains the subject of many immune-oncology debates due to its challenging diagnosis and management. Although it is currently defined by the restrictive Common Terminology Criteria for Adverse Events (CTCAE), the term of IRH covers a wide range of liver pathologies, including hepatitic, cholangitic, mixed, steatotic and nonspecific patterns of injury. Even when liver biopsy is performed, the recognized histopathological findings cannot predict the response to steroids or the need for secondary immunosuppression, and usually do not significantly modify the suggested empirical treatment of IRH. Beyond the CTCAE grading, a more comprehensive assessment of IRH severity, including laboratory biomarkers and clinical features, should be developed and a more patient-oriented management should be established by additional randomized evidence, incorporating hepatology and immune-oncology experience.

Immuno-oncology: a narrative review of gastrointestinal and hepatic toxicities

Vaccines, cytokines, and adoptive cellular therapies (ACT) represent immuno-therapeutic modalities with great development potential, and they are currently approved for the treatment of a limited number of advanced malignancies. The most up-to-date knowledge on the regulation of the anti-cancer immune response has recently led to the development and approval of inhibitors of immune checkpoints, which have produced unprecedented clinical activity in several hard to treat solid malignancies. However, severe adverse events (AEs) represent a limitation to the use of these drugs. Currently approved checkpoint inhibitors block cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), programmed cell death protein (PD-1) and its ligand (PD-L1), resulted in increased survival of patients with several solid and hematologic malignancies. The most common treatment AEs associated with these drugs are fatigue, rash, and auto-immune/inflammatory reactions. Many of the immune-related AEs are reversible and the strategies for their management include supportive care either with or without treatment withdrawal; nevertheless, in severe cases, hospitalization and treatment with immune suppressants, and/or immunomodulators may be required. Steroid therapy is a critical component of the treatment algorithm; nevertheless, the associated immunosuppression may compromise the antitumor response. This article provides a comprehensive and narrative review of luminal gastrointestinal and hepatic complications, including recommendations for their investigation and management.

AGA Clinical Practice Update on Diagnosis and Management of Immune Checkpoint Inhibitor Colitis and Hepatitis: Expert Review

BACKGROUND & AIMS

Immune checkpoint inhibitors (ICIs) have transformed the treatment landscape for oncology, leading to durable remissions in a subset of patients, but also a broad range of potentially life-threatening inflammatory toxicities, many of which involve the gastrointestinal (GI) tract and liver. The purpose of this expert review was to update gastroenterologists on the gastrointestinal and hepatic toxicities of ICIs and provide best practice advice on their diagnosis and management.

METHODS

The evidence reviewed in this work combines the expert clinical opinion of the authors with a comprehensive search of several English-language databases and a manual review of relevant publications.

Liver biopsy findings in patients on immune checkpoint inhibitors

Immune checkpoint inhibitors (ICI) can induce a durable response against a wide range of malignancies but cause immune related adverse events. The purpose of this study was to evaluate whether the pattern of inflammation in a liver biopsy in patients on ICIs is likely to be related to ICIs or other causes, and whether the pattern correlates with LFT abnormalities, imaging findings, and responsiveness to steroids. Cancer patients on ICIs who underwent liver biopsy were identified. Clinical data were obtained from electronic records. Liver biopsies were recorded as hepatitic, cholangitic, mixed, steatotic, or as mild nonspecific changes. In total, 28 liver biopsies had a predominantly hepatitic pattern of inflammation, including 11 biopsies with granulomas and 10 with endothelialitis. Eight biopsies had a mixed hepatocytic and cholangitic pattern of injury, including 6 with granulomas and 4 with endothelialitis. Sixteen patients had a predominantly cholangitic pattern, with portal-based inflammation. Three patients had a pattern resembling fatty liver, and five had mild nonspecific changes. The three most common histologic patterns correlated with the pattern of LFT abnormalities. The majority of patients with a cholangitic pattern had competing causes for elevated LFTs, including disease progression or concomitant chemotherapy. The cholangitic pattern was more likely to have bile duct dilatation or narrowing on liver imaging. The pattern of inflammation, degree of lobular injury, or presence of granulomas or endothelialitis did not predict response to steroids or the need for secondary immunosuppression. In this retrospective study, the pattern of inflammation did not predict the need for steroids, the length of time that steroids is required, or the need for secondary immunosuppression. A cholangitic pattern was seen when the pattern of LFTs was cholestatic, and was associated with imaging abnormalities of the bile duct, but a similar pattern was seen in bile duct obstruction and other drug reactions.

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.

Outcomes after resumption of immune checkpoint inhibitor therapy after high-grade immune-mediated hepatitis

BACKGROUND

In the current study, the authors assessed the risks and outcomes of immune checkpoint inhibitor (ICI) rechallenge in patients with resolved grade 3 to 4 ICI hepatitis because current guidelines recommend permanent ICI discontinuation in these patients.

METHODS

The authors performed a retrospective cohort study from 2010 through 2019 of patients with melanoma who were treated with ≥1 ICIs and who recovered from grade 3 to 4 ICI hepatitis. The primary outcome was hepatitis recurrence and the secondary outcome was the development of any immune-related adverse event (irAE) requiring the discontinuation of ICI rechallenge. Best overall response and time to all-cause death were compared between the patients who did and those who did not undergo ICI rechallenge. Grading was performed using the National Cancer Institute Common Terminology Criteria for Adverse Events (version 5.0).

RESULTS

Of the 102 patients with melanoma who developed high-grade ICI hepatitis, 31 underwent ICI rechallenge. Although 15 of 31 patients (48%) developed an irAE of any grade, only 6 patients (19%) required ICI discontinuation due to irAE severity (4 of 29 patients [14%] rechallenged with anti-PD-1 or anti-PD-L1 and 2 of 2 patients [100%] rechallenged with ipilimumab). Recurrent hepatitis accounted for 4 of these 6 cases. Rechallenged patients who did not require ICI discontinuation were found to be significantly less likely to receive ipilimumab rather than anti-PD-1 or anti-PD-L1 monotherapy (0% vs 33%; relative risk (RR), 0.1 [95% CI, 0.1-0.3; P = .032]) and significantly less likely to be rechallenged with their original ICI (8% vs 50%; RR, 0.2 [95% CI, 0.1-0.7; P = .038]). There was no difference noted with regard to best overall response or time to death between rechallenged and non-rechallenged patients.

CONCLUSIONS

ICI therapy can be resumed in patients with melanoma who have recovered from grade 3 to 4 ICI hepatitis with a modest risk of serious irAEs. It remains unclear whether ICI retreatment improves clinical outcomes.

Multinational Association of Supportive Care in Cancer (MASCC) 2020 clinical practice recommendations for the management of severe gastrointestinal and hepatic toxicities from checkpoint inhibitors

Immune-related adverse events (IrAEs) affecting the gastrointestinal (GI) tract and liver are among the most frequent and most severe inflammatory toxicities from contemporary immunotherapy. Inflammation of the colon and or small intestines (entero)colitis is the single most common GI IrAE and is an important cause of delay of discontinuation of immunotherapy. The severity of these GI IrAEs can range from manageable with symptomatic treatment alone to life-threatening complications, including perforation and liver failure. The frequency and severity of GI IrAEs is dependent on the specific immunotherapy given, with cytotoxic T lymphocyte antigen (CTLA)-4 blockade more likely to induce severe GI IrAEs than blockade of either programmed cell death protein 1 (PD-1) or PD-1 ligand (PD-L1), and combination therapy showing the highest rate of GI IrAEs, particularly in the liver. To date, we have minimal prospective data on the appropriate diagnosis and management of GI IrAEs, and recommendations are based largely on retrospective data and expert opinion. Although clinical diagnoses of GI IrAEs are common, biopsy is the gold standard for diagnosis of both immunotherapy-induced enterocolitis and hepatitis and can play an important role in excluding competing, though less common, diagnoses and ensuring optimal management. GI IrAEs typically respond to high-dose corticosteroids, though a significant fraction of patients requires secondary immune suppression. For colitis, both TNF-α blockade with infliximab and integrin inhibition with vedolizumab have proved highly effective in corticosteroid-refractory cases. Detailed guidelines have been published for the management of low-grade GI IrAEs. In the setting of more severe toxicities, involvement of a GI specialist is generally recommended. The purpose of this review is to survey the available literature and provide management recommendations focused on the GI specialist.

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.

Hepatobiliary Adverse Events

Immune checkpoint inhibitors (ICIs) are increasingly used for multiple cancer types. Hepatotoxicity is a reported adverse event of ICI treatment. It can present as asymptomatic elevation of aspartate transaminase and alanine transaminase or symptomatic hepatitis with fever, malaise, and even death in rare cases. The diagnosis of ICI-induced hepatitis is made after exclusion of other etiologies based on medical history, laboratory evaluation, and imaging and histological findings. Treatment of ICI-induced hepatitis consists of ICI discontinuation and immunosuppression in severe cases. Pancreatic injury as asymptomatic lipase elevation or acute pancreatitis-like disease with abdominal pain and evidence on imaging has been documented as a toxicity of ICI therapy. Appropriate treatment of pancreatitis still needs further investigation. Few cases, reports, and series documented cholecystitis and cholangitis as possible adverse events related to ICI therapy as well.

PD-L1 expressing granulomatous reaction as an on-target mechanism of steroid-refractory immune hepatotoxicity

Immune-related hepatitis is an important toxicity from immune-checkpoint inhibitor therapy, affecting up to 20% of patients on dual cytotoxic T-lymphocyte antigen 4/programmed cell death 1 (CTLA-4/PD-1) inhibitors. The mechanisms underlying this type of drug-induced liver injury are poorly understood. We report the case of a patient with immune-checkpoint inhibitor-related hepatitis where the presence of a diffuse granulomatous, PD-L1-positive infiltrate on liver biopsy correlated with poor response to corticosteroids. Our findings suggest a potential role for activation of the PD-1 pathway within the histiocitic infiltrate as a mechanism of toxicity. Further studies should address the role of macrophages in this patient group characterized by steroid-refractoriness.

Gastrointestinal and Hepatic Complications of Immunotherapy: Current Management and Future Perspectives

PURPOSE OF REVIEW

Checkpoint inhibitor (CPI) immunotherapy has transformed the treatment of multiple cancers over the past decade, leading to durable remissions, but also to severe inflammatory toxicities. These toxicities, termed immune-related adverse events (irAEs), can affect any organ system in the body, but commonly induce inflammation in barrier organs. Gastrointestinal (GI) and hepatic irAEs are among the most frequent and most severe from contemporary immunotherapies, with inflammation in the colon and or small intestines (entero)colitis as the single most common GI irAE. The aim of this review is to describe the evidence supporting our current understanding of CPI enterocolitis and hepatitis, as well as the management of these entities.

RECENT FINDINGS

Although most patients who develop enterocolitis recover without long-term GI sequelae, enterocolitis is still an important reason for treatment discontinuation, which, in patients with metastatic cancer, can be a life-threatening outcome. At present, we have almost no prospective, randomized data regarding the management of CPI enterocolitis, and current management algorithms are based on expert opinion and small retrospective studies with a high likelihood of bias. Retrospective studies have defined colonic ulceration as a predictor of colitis responsiveness to corticosteroids, and have defined microscopic colitis as a subtype of CPI enterocolitis with a distinct treatment response. Corticosteroids appear to be effective for 60-70% of patients with CPI enterocolitis, with about a third of patients requiring escalation to a biologic agent such as infliximab or vedolizumab. Yet proper sequencing of these treatments to minimize risk and maximize treatment benefit has not been established, and we do not know how treatment of colitis influences cancer outcomes. CPI enterocolitis and hepatitis are important causes of treatment interruption and discontinue, and significant morbidity in patients undergoing immunotherapy. As guidelines for diagnosis and management rely heavily on expert opinion, we have an urgent need for randomized and prospective trials that use both colitis and cancer outcomes to determine optimal management strategies.

Clinical Characteristics and Adverse Impact of Hepatotoxicity due to Immune Checkpoint Inhibitors

INTRODUCTION

We conducted this study to characterize the incidence, clinical features, treatment, and outcomes of immune checkpoint inhibitor (ICI) hepatotoxicity.

METHODS

Patients who received ICIs (with either single-agent or combination regimens) from January 1, 2010, to March 31, 2018, were identified. Hepatotoxicity was defined as alanine aminotransferase (ALT) >5 times the upper limit of normal (ULN), in the absence of an alternate cause, and categorized as grade 3 (ALT 5-20× ULN) or grade 4 (ALT >20× ULN), according to Common Terminology Criteria for Adverse Events 4.03.

RESULTS

Among 5,762 patients, 100 (2%) developed hepatotoxicity, occurring in a higher proportion of recipients of combination therapy (9.2%) compared with monotherapy (up to 1.7%, P < 0.001). ICIs were discontinued permanently in 69 and temporarily in 31 patients. Sixty-seven patients received steroids, 10 of whom (14%) had recurrent hepatotoxicity after the steroid taper. Thirty-one patients resumed ICIs after ALT improvement, 8 of whom (26%) developed recurrent hepatotoxicity. Characteristics of liver injury, response to steroids, and outcomes were similar between 38 individuals with and 62 without possible pre-existing liver disease. The severity and outcome of hepatotoxicity due to combination therapy were not significantly different from monotherapy. There were 36 deaths. Two had liver failure at the time of death, both with progression of liver metastases and grade 3 hepatotoxicity.

DISCUSSION

Clinically significant ICI-related hepatotoxicity was uncommon but led to permanent ICI discontinuation in the majority. ICIs were restarted in a sizable proportion of patients, most of whom did not experience recurrent hepatotoxicity.

Liver Histology: Diagnostic and Prognostic Features

When patients with suspected drug-induced liver injury (DILI) undergo liver biopsy, the pathologist can provide a wealth of information on the morphologic changes. The most common histologic patterns of DILI include mimics of acute and chronic hepatitis as well as acute cholestasis, chronic cholestasis, and a mixed pattern that combines hepatitis with cholestasis. The pattern may suggest etiologies of injury or correlate with reported patterns of injury for specific agents. Biopsy may exonerate or indict particular drugs as causal agents of injury and provide specific information on severity of injury and specific types of changes related to various outcomes.

Immune-related adverse reactions in the hepatobiliary system: second-generation check-point inhibitors highlight diverse histological changes

AIMS

Immune check-point inhibitors are known to cause immune-mediated adverse liver injury, but our knowledge is mainly based on cases treated with ipilimumab or nivolumab.

METHODS AND RESULTS

Clinicopathological features of 10 patients with hepatobiliary adverse reactions caused by second-generation drugs, pembrolizumab (n = 6) and atezolizumab (n = 4), were reviewed. Liver dysfunction developed during a median period of 3.5 weeks after administration of the check-point inhibitor (3 days-1 year). Antinuclear antibodies were detected in two patients at a low titre (1/80), and serum IgG concentrations were also only mildly elevated in two patients. Liver biopsies showed panlobular hepatitis (n = 5), cholangiopathic changes (n = 2), granulomatous injury (n = 2) and bland cholestasis (n = 1). Two cases of cholangiopathy (both pembrolizumab-treated) showed diffuse sclerosing cholangitis on imaging, and one also presented lymphocytic cholangitis resembling primary biliary cholangitis on biopsy. In two atezolizumab-treated cases, Küpffer cells were hyperplastic and aggregated, forming microgranulomas. Confluent necrosis and eosinophilic or plasma cell infiltration were rare. On immunostaining, the ratio of CD8⁺ /CD4⁺ cells was 12.2 ± 5.1, which was significantly higher than that in autoimmune hepatitis (2.7 ± 1.1; P < 0.001) or idiosyncratic drug-induced liver injury (5.0 ± 1.1; P = 0.014). All patients responded to steroid therapy, but it was less effective in patients with sclerosing cholangitis.

CONCLUSIONS

Pembrolizumab and atezolizumab manifested not only lobular hepatitis but also sclerosing cholangitis, lymphocytic duct injury and granulomatous hepatitis, probably representing various impaired cellular functions in CD8⁺ lymphocytes and macrophages due to blockage of PD-1-PD-L1 interaction.

Adverse effects of immune-checkpoint inhibitors: epidemiology, management and surveillance

Immune-checkpoint inhibitors (ICIs), including anti-cytotoxic T lymphocyte antigen 4 (CTLA-4), anti-programmed cell death 1 (PD-1) and anti-programmed cell death 1 ligand 1 (PD-L1) antibodies, are arguably the most important development in cancer therapy over the past decade. The indications for these agents continue to expand across malignancies and disease settings, thus reshaping many of the previous standard-of-care approaches and bringing new hope to patients. One of the costs of these advances is the emergence of a new spectrum of immune-related adverse events (irAEs), which are often distinctly different from the classical chemotherapy-related toxicities. Owing to the growing use of ICIs in oncology, clinicians will increasingly be confronted with common but also rare irAEs; hence, awareness needs to be raised regarding the clinical presentation, diagnosis and management of these toxicities. In this Review, we provide an overview of the various types of irAEs that have emerged to date. We discuss the epidemiology of these events and their kinetics, risk factors, subtypes and pathophysiology, as well as new insights regarding screening and surveillance strategies. We also highlight the most important aspects of the management of irAEs.

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.

Something old, something new: liver injury associated with total parenteral nutrition therapy and immune checkpoint inhibitors

Drug-induced liver injury (DILI) is a challenging and constantly changing field. The pathologist plays a key role in interpreting liver biopsies by classifying the pattern of injury, grading the severity of injury, and evaluating for other possible causes. Reports of iatrogenic liver injury are reviewed here with a focus on total parenteral nutrition (ie, intestinal failure-associated liver disease [IFALD]) and immune checkpoint inhibitors (ICIs). The hallmark features of IFALD are cholestasis and steatosis. Cholestasis is more common in infants, whereas steatosis and steatohepatitis are more commonly seen in older children and adults. Infants tend to have a faster progression to fibrosis and cirrhosis. Perivenular fibrosis and ductopenia may also be seen in IFALD. Although fish oil-based lipid emulsions can reverse cholestasis, recent studies have shown persistent or progressive fibrosis. ICI-induced liver injury usually presents as an acute hepatitis with features similar to those seen in idiopathic autoimmune hepatitis and drug-induced autoimmune hepatitis. However, it lacks a prominent plasma cell infiltrate and serological markers of autoimmune hepatitis. Other features such as fibrin ring granulomas and cholangitis have also been reported in association with ICIs. Treatment for ICI-induced liver injury includes corticosteroids and other immunosuppressants.

Immunotherapy-related hepatitis: real-world experience from a tertiary centre

OBJECTIVE

Immune checkpoint inhibitors like anti-programmed cell death protein 1 (PD-1) drugs Nivolumab and Pembrolizumab and anti-cytotoxic T-lymphocyte associated (CTLA-4) drug Ipilimumab have become standard of care in many metastatic cancers. Immunotherapy-related hepatitis and cholangitis present a diagnostic and management challenge, being rare and incompletely characterised. We aim to report the incidence, features and treatments used for this in a real-world setting and to identify useful biomarkers, which can be used to predict effective use of steroids.

DESIGN

Retrospective review of 453 patients started on immunotherapy over 7 years.

SETTING

Tertiary hepatology and oncology centre.

PATIENTS

21 patients identified with immunotherapy-related hepatotoxicity.

RESULTS

Hepatitis was most common in those receiving dual therapy (incidence 20%), with 75% of Grade 4 hepatitis cases occurring with ipilimumab-containing regimens. Corticosteroid monotherapy is first line treatment, but doses above 60 mg OD prednisolone do not demonstrate any additional benefit in time to hepatitis resolution. The alanine transaminase (ALT) reduction in steroid-responsive hepatitis is typically rapid (with a halving of ALT within 11 days). The commencement of additional immunosuppression (typically mycophenolate) appears safe and prompts a more rapid fall in ALT than corticosteroid use alone. Infliximab was safely used twice as hepatitis treatment. We also describe one patient with rare immunotherapy-induced biliary disease.

CONCLUSIONS

Vigilance is required for detection of immunotherapy-associated liver disease as, other than dual immunotherapy, we can identify no predictive factors for its development. Our data suggest that corticosteroid response is not dependent on the higher dosing regimens. Early escalation of immunosuppression may be of benefit in the absence of a rapid response to corticosteroids.

Checkpoint inhibitor-induced liver injury: A novel form of liver disease emerging in the era of cancer immunotherapy

Liver injury triggered by immune checkpoint inhibitors has been increasingly seen in clinical practice, and the incidence is likely to rise further in the next several years because of expanded indications for cancer immunotherapy. Tissue damage driven by disrupted immune tolerance against self-antigens is called an immune-related adverse event (irAE). irAEs in the liver histologically presents panlobular hepatitis (∼70%), isolated central zonal necrosis (∼20%), primarily granulomatous hepatitis (∼5%), and other minor forms of tissue injury (∼5%). Infiltrating cells are mainly lymphocytes and occasional eosinophils. Unlike classic autoimmune hepatitis (AIH), plasma cell infiltration is not conspicuous. Immunostaining reveals a large number of CD8+ T lymphocytes and a markedly smaller number of CD4+ cells or CD20+ B lymphocytes. The unique CD3+/CD20+ and CD4+/CD8+ ratios shifted in favor of CD8+ cytotoxic T lymphocytes are helpful to discriminate irAEs from other conditions (e.g., AIH, idiosyncratic drug-induced liver injury). Another hepatobiliary manifestation of irAEs is sclerosing cholangitis clinically characterized by elevations of biliary enzymes, diffuse duct wall thickening, and duct dilatation. Lymphocytic infiltration can be observed by endoscopic biopsies from the thick extrahepatic bile ducts, and liver needle biopsies may also show severe lymphocytic cholangitis resembling primary biliary cholangitis. An important differential diagnosis of irAEs is previously asymptomatic or subclinical liver disease unmasked by cancer immunotherapy, which is often challenging and requires close clinicopathological correlations.

Immune inhibitory proteins and their pathogenic and therapeutic implications in autoimmunity and autoimmune hepatitis

Key inhibitory proteins can blunt immune responses to self-antigens, and deficiencies in this repertoire may promote autoimmunity. The goals of this review are to describe the key immune inhibitory proteins, indicate their possible impact on the development of autoimmune disease, especially autoimmune hepatitis, and encourage studies to clarify their pathogenic role and candidacy as therapeutic targets. English abstracts were identified in PubMed by multiple search terms. Full length articles were selected for review, and secondary and tertiary bibliographies were developed. Cytotoxic T lymphocyte antigen-4 impairs ligation of CD28 to B7 ligands on antigen presenting cells and inhibits the adaptive immune response by increasing anti-inflammatory cytokines, generating regulatory T cells, and reducing T cell activation and proliferation. Programed cell death antigen-1 inhibits T cell selection, activation, and proliferation by binding with two ligands at different phases and locations of the immune response. A soluble alternatively spliced variant of this protein can dampen the inhibitory signal. Autoimmune hepatitis has been associated with polymorphisms of the cytotoxic T lymphocyte antigen-4 gene, reduced hepatic expression of a ligand of programed cell death antigen-1, an interfering soluble variant of this key inhibitory protein, and antibodies against it. Findings have been associated with laboratory indices of liver injury and suboptimal treatment response. Abatacept, belatacept, CD28 blockade, and induction of T cell exhaustion are management considerations that require scrutiny. In conclusion, deficiencies in key immune inhibitory proteins may promote the occurrence of autoimmune diseases, such as autoimmune hepatitis, and emerging interventions may overcome these deficiencies. Investigations should define the nature, impact and management of these inhibitory disturbances in autoimmune hepatitis.

[The pathology of adverse events with immune checkpoint inhibitors]

BACKGROUND

Immunotherapy has gained importance with the development of new effective cancer treatments. Immune checkpoint inhibitors (ICI) are monoclonal antibodies that promote T‑cell mediated tumor immune rejection. Checkpoint blockade also carries the risk of inducing autoimmune reactions ("immune related adverse events", irAEs). The diagnosis and classification of irAEs constitute a new and important field in pathology.

AIM

Practice-oriented review of the diagnosis and classification of irAEs.

MATERIALS AND METHODS

Structured, selective literature review based on PubMed und UpToDate ® online.

RESULTS

The most common irAEs affect the skin, the gastrointestinal tract, the liver, and the respiratory system. The correct diagnosis and classification of irAEs by an interdisciplinary care team is essential for appropriate therapy and the prevention of long-term sequelae. Other important irAEs affect the endocrine organs, the heart, the joints, the kidneys and the nervous system. Because of their rarity and/or limited options for bioptic diagnosis, only limited data on the morphology and pathophysiology of these irAEs are currently available. Autopsies carried out after ICI therapy constitute an important element of quality control and allow better documentation of the incidence and pathogenesis of irAEs.

DISCUSSION

Pathology plays a central role in the diagnosis and treatment of irAEs. Future studies may contribute to a better mechanistic understanding of irAEs for individualized knowledge-based risk assessment.

Hepatotoxicity induced by immune checkpoint inhibitors: a comprehensive review including current and alternative management strategies

INTRODUCTION

Immune checkpoint inhibitors (ICIs) block cytotoxic T lymphocyte antigen 4 (CTLA-4) and programmed cell death protein 1 (PD-1)/PD ligand 1 (PD-L1) receptors that control antitumor activities of lymphocytes. While highly efficacious, these drugs have been associated with several immune-related adverse events (irAEs) due to the disruption of self-tolerance. Immune-mediated hepatitis (IMH) usually presents as mild elevations of liver enzymes though it can rarely be associated with life-threatening hepatic injury. Areas covered: A comprehensive review was performed to define the clinicopathologic forms of liver injury associated with ICIs, comparing the various ICI classes as well as comparing this form of IMH with idiopathic autoimmune hepatitis and drug-induced autoimmune hepatitis. Liver biopsy has proven very useful in selected patients. A specific form of fibrin ring granulomatous hepatitis appears to be associated with IMH. The current societal treatment algorithms and emerging data were reviewed to determine when to utilize corticosteroids. Expert opinion: Monitoring for severe ICI-IMH is recommended although acute liver failure remains rare. Most patients with grade 3-4 hepatotoxicity respond to corticosteroids, but a subset of patients with mild hepatitis on liver biopsy resolve without steroids and need to be carefully selected in concert with the consultation of a hepatologist.

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

INTRODUCTION

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.

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.

Cystic neutrophilic granulomatous mastitis with corynebacterium and staphylococcus mimicking breast carcinoma

Cystic neutrophilic granulomatous mastitis (CNGM) is an increasingly recognized entity in the differential diagnosis of granulomatous inflammation involving the breast. We present the first case report of CNGM mimicking carcinoma of the breast with two mixed bacterial species as the causative pathogens (Corynebacterium and Staphylococcus spp.).

Granulomas in the Liver, with a Focus on Infectious Causes

Hepatic granulomas are encountered in approximately 2% to 10% of liver biopsies. There are many potential infectious and noninfectious causes; granulomas can be generally classified by their morphology, which may be helpful in refining the differential diagnosis. This article provides a review of hepatic granulomas with an emphasis on infectious causes.

Diagnosis and Management of Hepatitis in Patients on Checkpoint Blockade

Many human tumors are recognized by the adaptive immune system, but these spontaneous antitumor responses are typically inadequate to mediate regression. Blockade of immune regulatory "checkpoint" receptors such as cytotoxic T-lymphocyte-associated antigen 4 and programmed cell death 1 can unleash antitumor immunity, resulting in tumor responses that can be durable. Alongside the enormous promise of immunotherapy for cancer, the immune dysregulation of checkpoint blockade has led to a plethora of new autoimmune adverse events. Hepatic toxicity occurs in 1%-17% of patients on immune checkpoint inhibitors, with the precise incidence dependent on both the drug used and the underlying malignancy. Hepatitis is most commonly a low-grade toxicity, but grade 3 and 4 hepatotoxicity does occur. Here we will answer frequently asked questions regarding immune-related hepatitis to assist in the recognition and management of this important condition.

KEY POINTS

Immune related hepatitis is a potentially serious complication of checkpoint blockade.The differential for elevated liver function tests in patients on checkpoint blockade is broad.Diagnostic testing such as viral serologies, liver ultrasound, cross sectional imaging, and liver biopsy may help in the diagnosis of immune related hepatitis in select patients.Patients with underlying cirrhosis are an at risk population for whom current grading criteria may underestimate the severity of liver inflammation.Severe immune related hepatitis is best managed by a multi-disciplinary team that includes a hepatologist.Most patients with immune related hepatitis respond to corticosteroids, but a substantial fraction require treatment with a secondary immunosuppressive agent.

[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.

Sarcoid-Like Granulomatosis Induced by Nivolumab Treatment in a Lung Cancer Patient

Nivolumab, an anti-PD-1 antibody, inhibits binding between PD-1 and PD-1 ligand and activates antigen-specific T cells that have become unresponsive to cancer cells. Although it is recommended as a second-line therapy in gene mutation-negative non-small-cell lung cancer, interstitial pneumonia is a well-known side effect of the drug; however, granulomatous lesions have rarely been reported. We describe the case of an 81-year-old male with cT1aN2M1b stage IV pleomorphic carcinoma of the left upper lobe of the lung. After primary treatment with carboplatin and paclitaxel, recurrence was observed in the left supraclavicular lymph node and left adrenal gland. We initiated the administration of nivolumab as a secondary treatment. Reduction was observed in the swelling of the left supraclavicular lymph node and left adrenal gland, but the tumor shadow in the right upper lobe appeared to increase. Bronchoscopy was performed, and the biopsy result showed granulomas; the findings resembled a sarcoid-like granulomatous reaction. The shadows eventually disappeared with nivolumab discontinuation; thus, we concluded that the sarcoid-like granulomatous reaction had resulted from nivolumab administration. Based on our observations, we suggest that when invasive shadows are observed after nivolumab administration, it is necessary to differentiate between disease progression and interstitial pneumonia. Moreover, the decision to reinitiate nivolumab treatment requires careful judgment in future instances of cancer recurrence.

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.