Ipilimumab associated hepatitis: imaging and clinicopathologic findings

Gastrointestinal and Hepatic Complications of Immune Checkpoint Inhibitors

PURPOSE OF REVIEW

Gastrointestinal complications are very common in patients undergoing cancer treatment. Some of these complications can be life threatening and require prompt and appropriate diagnosis and treatment. The purpose of this review is to address luminal gastrointestinal and hepatic complications associated with a new class of anticancer drugs, immune checkpoint inhibitors (CPIs), and focuses on the identification, evaluation, and management of the complications associated with this class of drugs.

RECENT FINDINGS

It is now recognized that immune checkpoint inhibitors are frequently associated with luminal GI side effects such as diarrhea and enterocolitis and hepatic complications such as hepatitis. While colitis associated with CPIs, to some extent, mimics that found in idiopathic inflammatory bowel disease, the complex interplay of genes, the environment, the immune system, and the microbiome make it difficult to fully differentiate these conditions clinically. CPI-induced hepatitis is most often associated with a pattern of hepatocellular injury with panlobular hepatitis. A variety of biomarkers have been proposed to predict an adverse response to CPIs and are under investigation. It has been proposed that alterations in the microbiome may impact the risk of developing colitis, and these studies are reviewed. In contrast to idiopathic chronic inflammatory bowel disease, CPI-induced colitis is often reversible if rapidly treated in accordance with the immune-mediated adverse reaction management guidelines. Treatment algorithms have been suggested but are, to some extent, empiric and based on algorithms for the treatment of idiopathic inflammatory bowel disorders. CPIs may be associated with significant GI complications which impact their successful use in the treatment of neoplastic diseases. Much of what we currently know about the mechanisms and treatment of these complications is empiric and extrapolated from experience with idiopathic inflammatory bowel disease and other immune disorders. Current research focuses on understanding genetic predisposition and the role of the microbiome and identifying predictive risk markers for developing complications.

Managing Adverse Events With Immune Checkpoint Agents

Immune checkpoint inhibitors (anti-cytotoxic T-lymphocyte antigen 4 and anti programmed cell death 1/programmed cell death 1 ligand antibodies) have shown impressive clinical activity in multiple cancer types. Despite achieving great clinical success, challenges and limitations of these drugs as monotherapy or various combinational strategies include the development of a unique set of immune-related adverse events (irAEs) that can be severe and even fatal. Therefore, identification of patients at risk, prevention, consistent communication between patients and medical team, rapid recognition, and treatment of irAEs are critical in optimizing treatment outcomes. This review focuses on the description of more common irAEs and provides a suggested approach for management of specific irAEs.

Immune-Checkpoint Inhibitors in the Era of Precision Medicine: What Radiologists Should Know

Over the past five years immune-checkpoint inhibitors have dramatically changed the therapeutic landscape of advanced solid and hematologic malignancies. The currently approved immune-checkpoint inhibitors include antibodies to cytotoxic T-lymphocyte antigen-4, programmed cell death (PD-1), and programmed cell death ligand (PD-L1 and PD-L2). Response to immune-checkpoint inhibitors is evaluated on imaging using the immune-related response criteria. Activation of immune system results in a unique toxicity profile termed immune-related adverse events. This article will review the molecular mechanism, clinical applications, imaging of immune-related response patterns and adverse events associated with immune-checkpoint inhibitors.

Adverse Events in Cancer Immunotherapy

Cancer immunotherapy has resulted in durable responses in patients with metastatic disease, unseen with traditional chemotherapy. Several therapies have been approved by the Food and Drug Administration for the treatment of various cancers, including: immune checkpoint inhibitors, cytokines - interleukin 2 (IL-2) and interferon alpha (IFN), and the cancer vaccine sipuleucel-T. These therapies upregulate the immune system to enhance antitumor responses. As a consequence, they can cause inflammatory and immune-related adverse events that can affect one or more organs, can be serious, and on occasion lifethreatening. The management of these adverse events is complex, and requires a multidisciplinary approach involving not only oncologists, but also other internal medicine specialists, to ensure prompt diagnosis and optimal management of these complications.

Incidence and risk of hepatic toxicities with PD-1 inhibitors in cancer patients: a meta-analysis

PURPOSE

Anti-programmed cell death receptor-1 (PD-1) antibodies have demonstrated antitumor activity in many cancer entities. Hepatic adverse events (AEs) are one of its major side effects, but the overall risks have not been systematically evaluated. Thus, we conducted this meta-analysis to investigate the overall incidence and risk of developing hepatic AEs in cancer patients treated with PD-1 inhibitors.

METHODS

PubMed, Embase, and oncology conference proceedings were searched for relevant studies. Eligible studies were randomized controlled trials of cancer patients treated with PD-1 inhibitors with adequate data on hepatic AEs.

RESULTS

A total of nine randomized controlled trials with a variety of solid tumors were eligible for the meta-analysis. The use of PD-1 inhibitors significantly increased the risk of developing all-grade hepatic AEs but not for high-grade hepatic AEs in comparison with chemotherapy or everolimus control. Additionally, the risk of all-grade and high-grade hepatic AEs with a nivolumab/ipilimumab combination was substantially higher than ipilimumab. No significant differences in the risk of all-grade and high-grade hepatic AEs were found between PD-1 inhibitors monotherapy and ipilimumab.

CONCLUSION

While the use of PD-1 inhibitors is associated with an increased risk of developing hepatic AEs in cancer patients, this is primarily for lower grade events.

Overview and management of toxicities of immune checkpoint-blocking drugs

Immunotherapy is considered to be the most important breakthrough in cancer management in the past few years. This success was based on the scientific understanding of immune mechanisms due to improvement in preclinical science and the introduction of new methods of investigation. Immune checkpoint inhibitors (ICIs) are among the most promising drugs in the field of immune-oncology; they represent monoclonal antibodies that modulate the effects of immune checkpoints, such as cytotoxic T lymphocyte Antigen 4 (CTLA-4) and Programmed Cell Death protein 1 (PD-1), which are co-inhibitory signals responsible for immune suppression. Despite clinical benefits, ICIs are immune activating agents that are associated with a number of important side effects (immune-related adverse events-irAEs), attributed to organ-specific inflammation. Herein, we review the toxicities of ICIs, highlighting the importance of early identification and management.

Immune-Related Adverse Events From Immune Checkpoint Inhibitors

Immunotherapy for cancer treatment has come of age, specifically with the use of immune checkpoint antibodies directed against molecules such as CTLA-4, PD-1, and PD-L1. Single-agent and combinatorial approaches utilizing these agents and other immunotherapies that may enhance antitumor effects are under investigation. With increasing clinical use of these agents, an appreciation for their toxicities comes to the fore. Adverse events that occur as a result of the immunologic effects of these therapies are termed "immune-related adverse events" (irAEs), and range in both frequency and severity in reported single-agent and combination studies. Improvements in our understanding of how and why irAEs develop and how to effectively manage them are needed. Herein we provide a state-of-the-art synopsis of the incidence, clinical features, mechanisms, and management of selected irAEs with immune checkpoint inhibitors currently in use.

Cutaneous, gastrointestinal, hepatic, endocrine, and renal side-effects of anti-PD-1 therapy

BACKGROUND

Anti-programmed cell death receptor-1 (PD-1) antibodies represent an effective treatment option for metastatic melanoma as well as for other cancer entities. They act via blockade of the PD-1 receptor, an inhibitor of the T-cell effector mechanisms that limit immune responses against tumours. As reported for ipilimumab, the anti-PD-1 antibodies pembrolizumab and nivolumab can induce immune-related adverse events (irAEs). These side-effects affect skin, gastrointestinal tract, liver, endocrine system and other organ systems. Since life-threatening and fatal irAEs have been reported, adequate diagnosis and management are essential.

METHODS AND FINDINGS

In total, 496 patients with metastatic melanoma from 15 skin cancer centers were treated with pembrolizumab or nivolumab; 242 side-effects were described in 138 patients. In 116 of the 138 patients, side-effects affected the skin, gastrointestinal tract, liver, endocrine, and renal system. Rare side-effects included diabetes mellitus, lichen planus, and pancreas insufficiency due to pancreatitis.

CONCLUSION

Anti-PD1 antibodies can induce a plethora of irAEs. The knowledge of them will allow prompt diagnosis and improve the management resulting in decreased morbidity.

Managing immune checkpoint-blocking antibody side effects

Immune checkpoint-blocking antibodies that enhance the immune system's ability to fight cancer are becoming important components of treatment for patients with a variety of malignancies. Cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) was the first immune checkpoint to be clinically targeted, and ipilimumab, an inhibitor of CTLA-4, was approved by the U.S. Food and Drug Administration (FDA) for patients with advanced melanoma. The programmed cell death-1 (PD-1) receptor and one of its ligands, PD-L1, more recently have shown great promise as therapeutic targets in a variety of malignancies. Nivolumab and pembrolizumab recently have been FDA- approved for patients with melanoma and additional approvals within this therapeutic class are expected. The use of anti-CTLA-4 and anti-PD-1/PD-L1 antibodies is associated with side effects known as immune-related adverse events (irAEs). Immune-related adverse events affect the dermatologic, gastrointestinal, hepatic, endocrine, and other organ systems. Temporary immunosuppression with corticosteroids, tumor necrosis factor-alpha antagonists, mycophenolate mofetil, or other agents can be effective treatment. This article describes the side-effect profile of the checkpoint-blocking antibodies that target CTLA-4 and PD-1/PD-L1 and provides suggestions on how to manage specific irAEs.

Mechanisms of adaptation and progression in idiosyncratic drug induced liver injury, clinical implications

In the past decade our understanding of idiosyncratic drug induced liver injury (IDILI) and the contribution of genetic susceptibility and the adaptive immune system to the pathogenesis of this disease process has grown tremendously. One of the characteristics of IDILI is that it occurs rarely and only in a subset of individuals with a presumed susceptibility to the drug. Despite a clear association between single nucleotide polymorphisms in human leukocyte antigen (HLA) genes and certain drugs that cause IDILI, not all individuals with susceptible HLA genotypes develop clinically significant liver injury when exposed to drugs. The adaptation hypothesis has been put forth as an explanation for why only a small percentage of susceptible individuals develop overt IDILI and severe injury, while the majority with susceptible genotypes develop only mild abnormalities that resolve spontaneously upon continuation of the drug. This spontaneous resolution is referred to as clinical adaptation. Failure to adapt or defective adaptation leads to clinically significant liver injury. In this review we explore the immuno-tolerant microenvironment of the liver and the mechanisms of clinical adaptation in IDILI with a focus on the role of immune-tolerance and cellular adaptive responses.

Cancer immunotherapy: imaging assessment of novel treatment response patterns and immune-related adverse events

Cancer immunotherapy is changing the imaging evaluation of cancer treatment response and treatment-related toxic effects. New emerging patterns of treatment response and treatment-related toxic effects after treatment with immunomodulating agents have been observed. Treatment response after immunomodulatory therapy can be associated with significantly delayed decrease in tumor size, and new or enlarging tumors observed soon after completion of treatment may not reflect disease progression. In addition, activation of the immune system to fight cancer may lead to unwanted autoimmune-mediated toxic effects that could be mistaken for metastatic disease or misdiagnosed as a non-treatment-related process and delay appropriate clinical management. Radiologists must recognize the novel treatment response patterns and the wide range of autoimmune toxic effects, which should not be mistaken for treatment failure or metastatic disease progression.

Immune-related adverse events with immune checkpoint blockade: a comprehensive review

Cancer immunotherapy is coming of age; it has prompted a paradigm shift in oncology, in which therapeutic agents are used to target immune cells rather than cancer cells. The first generation of new immunotherapies corresponds to antagonistic antibodies that block specific immune checkpoint molecules cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), programmed cell death protein (PD-1) and its ligand PD-L1. Targeting these checkpoints in patients living with cancer had led to long-lasting tumour responses. By unbalancing the immune system, these new immunotherapies also generate dysimmune toxicities, called immune-related adverse events (IRAEs) that mainly involve the gut, skin, endocrine glands, liver, and lung but can potentially affect any tissue. In view of their undisputed clinical efficacy, anti-CTLA-4 and anti-PD-1 antibodies are entering in the routine oncological practice, and the number of patients exposed to these drugs will increase dramatically in the near future. Although steroids can be used to treat these IRAEs, the associated immunosuppression may compromise the antitumour response. Oncologists must be ready to detect and manage these new types of adverse events. This review focuses on the mechanisms of IRAE generation, putative relationship between dysimmune toxicity and antitumour efficacy, as a basis for management guidelines.

Toxicities of the anti-PD-1 and anti-PD-L1 immune checkpoint antibodies

Immune checkpoint antibodies that augment the programmed cell death protein 1 (PD-1)/PD-L1 pathway have demonstrated antitumor activity across multiple malignancies, and gained recent regulatory approval as single-agent therapy for the treatment of metastatic malignant melanoma and nonsmall-cell lung cancer. Knowledge of toxicities associated with PD-1/PD-L1 blockade, as well as effective management algorithms for these toxicities, is pivotal in order to optimize clinical efficacy and safety. In this article, we review selected published and presented clinical studies investigating single-agent anti-PD-1/PD-L1 therapy and trials of combination approaches with other standard anticancer therapies, in multiple tumor types. We summarize the key adverse events reported in these studies and their management algorithms.

Immune-mediated adverse events of anticytotoxic T lymphocyte-associated antigen 4 antibody therapy in metastatic melanoma

Ipilimumab, an antibody that blocks cytotoxic T lymphocyte-associated antigen 4 (CTLA-4; CD152), was approved by the Food and Drug Administration in 2011 for the treatment of unresectable stage III or IV malignant melanoma. Although the addition of this particular immunotherapy has broadened treatment options, immune-related adverse events (irAEs) are associated with ipilimumab therapy, including dermatologic effects, colitis and diarrhea, endocrine effects, hepatotoxicity, ocular effects, renal effects, neurologic effects, and others. In this article, a critical evaluation of the underlying mechanisms of irAEs associated with anti-CTLA-4 therapy is presented. Additionally, potentially beneficial effects of combinational therapies to alleviate ipilimumab-induced irAEs in malignant melanoma are discussed. Future research is warranted to elucidate the efficacy of such combination therapies and specific biomarkers that would help to predict a clinical response to ipilimumab in patients with malignant melanoma.

Ipilimumab-associated Hepatitis: Clinicopathologic Characterization in a Series of 11 Cases

Ipilimumab is a monoclonal antibody that inhibits the CTLA4 receptor on cytotoxic T lymphocytes, resulting in immune-mediated tumor cell death. Ipilimumab is most often used in the treatment of metastatic melanoma, and rarely liver toxicity necessitating cessation of treatment occurs. The aim of this study was to characterize the histologic features and clinical course of ipilimumab-associated hepatitis. Eleven patients with clinical suspicion of ipilimumab-induced hepatitis, due to the development of abnormal liver function tests (LFTs) while receiving treatment, and who underwent liver biopsy, were identified over a 6-year period. Ten patients were male and 1 female (median age 58 y), and all received 1 to 4 doses of ipilimumab. None had known preexisting liver disease. Two patients were obese, and another had a history of alcohol abuse. Viral and autoimmune serologies were negative in all patients except 1 who had a mildly elevated ANA titer. Nine biopsies showed active hepatitis with 2 distinct histologic patterns: panlobular hepatitis in 6 cases and zone 3 hepatitis in 3. The inflammatory infiltrate was similar in composition in both patterns, composed predominantly of CD8+ T lymphocytes, admixed histiocytes, scattered plasma cells, and eosinophils. Prominent histiocytic sinusoidal infiltrates were present in 7 cases and frequently formed loose histiocytic aggregates. Central vein endothelialitis was present in 8 cases. Patients in this group tended to have markedly elevated ALT, AST, and total bilirubin. Two cases did not fit into the above 2 histologic groups: 1 showed portal inflammation with cholangitis, and the other showed morphologic features indistinguishable from nonalcoholic steatohepatitis. Discontinuation of ipilimumab and administration of immunosuppressives resulted in resolution or marked improvement of LFTs in all patients within 3 months of presentation. Ipilimumab may potentially unmask previously subclinical liver disease, for example, fatty liver disease, and the diagnosis of ipilimumab-induced liver injury may only be recognized with certainty after cessation of the drug leads to normalization of LFTs. Overall, ipilimumab-associated hepatitis most often presents with a panlobular active hepatitis that resembles autoimmune hepatitis. Prominent sinusoidal histiocytic infiltrates and central vein damage with endothelialitis may be helpful histologic clues to the diagnosis of ipilimumab-associated hepatitis.

Risk of elevated transaminases in cancer patients treated with immune checkpoint inhibitors: a meta-analysis

BACKGROUND

This meta-analysis has been conducted to determine the risk of elevated transaminases associated with immune checkpoint inhibitors use in patients with cancer.

METHODS

Studies eligible for our analysis included randomized Phase II and III trials of patients with cancer on ipilimumab, nivolumab, pembrolizumab, tremelimumab and pidilizumab, which describe events of elevated transaminases [alanine aminotransferase (ALT) and aspartate aminotransferase (AST)].

RESULTS

Initial database search revealed 210 relevant citations. After excluding noneligible studies, 10 trials were considered eligible for the quantitative synthesis. The RR of all-grade elevated ALT and AST was 2.36 (95% CI 1.20-4.66; p = 0.01) and 1.53 (95% CI 0.73-3.22; p = 0.26), respectively, whereas for high-grade elevated ALT and AST, it was 11.27 (95% CI 5.38-23.63; p < 0.0001) and 4.9 (95% CI 2.97-8.09; p < 0.0001), respectively.

CONCLUSIONS

Our study has shown that the use of immune checkpoint inhibitors has a causal relationship to an increased risk of high-grade elevated ALT and AST. Clinicians using these agents should be attentive of this risk.

Ipilimumab-induced hepatitis on 18F-FDG PET/CT in a patient with malignant melanoma

A 78-year-old man with metastatic malignant melanoma underwent a restaging 18F-FDG PET/CT after initiation of ipilimumab therapy, a Food and Drug Administration-approved human monoclonal antibody targeting CTLA-4. PET/CT demonstrated intense FDG uptake fusing to poorly circumscribed hypodensities throughout the liver. Patient was experiencing high-grade fever, chills, and generalized fatigue at the time of imaging, as well as mildly elevated liver function tests. Patient was subsequently treated with corticosteroids for suspected ipilimumab-induced hepatitis, and the patient rapidly improved clinically. Follow-up PET/CT 2 months later revealed complete resolution of abnormal FDG uptake in the liver, confirming the diagnosis of ipilimumab-induced hepatitis.

Radiographic Profiling of Immune-Related Adverse Events in Advanced Melanoma Patients Treated with Ipilimumab

Ipilimumab is a promising novel immunotherapy agent and is associated with a variety of immune-related adverse events (irAE). The purpose of this study was to investigate the manifestations of irAEs on body imaging in patients with advanced melanoma treated with ipilimumab. One-hundred forty-seven patients with advanced melanoma (59 women, 88 men; median age, 64.5 years) treated with ipilimumab were studied. All patients had the baseline and at least one follow-up chest/abdomen/pelvis CT or PET/CT during therapy, which were reviewed by a consensus of two radiologists blinded to the clinical data. Findings indicative of individual types of irAEs were assessed, including thyroiditis, sarcoid-like lymphadenopathy, pneumonitis, hepatitis, pancreatitis, and colitis. Among the 147 patients, 46 (31%) had radiologically identified irAEs. The time interval from the initiation of therapy to the development of irAEs was less than 3 months in 76% (35 of 46) of the patients (range, 0.2-9.1 months). Clinical characteristics did not differ between patients with and without irAEs (P > 0.18). Among the individual types of irAEs, colitis was most common (n = 28; 19%), followed by sarcoid-like lymphadenopathy (n = 8; 5%) and pneumonitis (n = 8; 5%). Hepatitis (n = 3), thyroiditis (n = 2), and pancreatitis (n = 1) were less common. The resolution of irAEs was noted in 32 of 36 patients (89%) with further follow-up scans, with a median time of 2.3 months after the detection of irAE. In conclusion, irAEs were noted on body imaging in 31% of patients with melanoma treated with ipilimumab. Colitis was the most common, followed by sarcoid-like lymphadenopathy and pneumonitis. The results call for an increased awareness of irAEs, given the expanding role of cancer immunotherapy.

Ipilimumab-induced toxicities and the gastroenterologist

Ipilimumab has been shown to improve overall survival in patients with advanced melanoma. Ipilimumab acts through immune-modulation, and is recognized to cause potentially severe immune-related adverse events (irAEs) including dermatitis, colitis, thyroiditis, hypophysitis, and hepatitis. The acceptance of ipilimumab as a treatment for metastatic melanoma means patients will continue to be treated with this agent and gastroenterologists will be increasingly called upon to assist in managing severe autoimmune-related hepatitis and colitis. To date, the recommendations for managing irAEs secondary to ipilimumab have been steroids at a moderate dose of prednisolone (1 mg/kg) as well as immunosuppressive agents such as mycophenolate mofetil (MMF) for steroid-refractory hepatitis and infliximab in the management of corticosteroid-refractory colitis. However, the dosing and the duration of immunosuppressive therapy have not been systematically studied in the setting of treating ipilimumab-induced irAEs. Therefore, additional immune-modifying agents and/or a change in dosing may be required to manage severe irAEs unresponsive to existing treatment recommendations. We describe a treatment paradigm illustrated by a series of five patients who experienced irAEs. In three cases of metastatic melanoma, ipilimumab-induced hepatitis was successfully treated with high-dose parenteral pulsed methylprednisolone. In two other melanoma patients with ipilimumab-induced colitis, one patient had satisfactory resolution of his colitis with high-dose corticosteroid therapy alone and the other patient required infliximab infusion. We have reviewed the current literature and management algorithms for ipilimumab-induced irAEs. Treatment options and the rationale for their use are discussed, including the use of pulsed high-dose steroids, MMF, azathioprine and calcineurin inhibitors.

Cancer immunotherapy and immune-related response assessment: The role of radiologists in the new arena of cancer treatment

The recent advances in the clinical application of anti-cancer immunotherapeutic agents have opened a new arena for the treatment of advanced cancers. Cancer immunotherapy is associated with a variety of important radiographic features in the assessments of tumor response and immune-related adverse events, which calls for radiologists' awareness and in-depth knowledge on the topic. This article will provide the state-of-the art review and perspectives of cancer immunotherapy, including its molecular mechanisms, the strategies for immune-related response assessment on imaging and their pitfalls, and the emerging knowledge of radiologic manifestations of immune-related adverse events. The cutting edge clinical and radiologic investigations are presented to provide future directions.

Drug-induced liver injury: what was new in 2013?

INTRODUCTION

The year 2013 continued to highlight numerous aspects of drug-induced liver injury (DILI), with new information communicated via > 1500 publications. New reports of DILI were described and FDA warnings and alerts were issued for a number of products, emphasizing the risks related to hepatotoxicity.

AREAS COVERED

We provide a summary of the year's published reports of new causes of DILI, along with reviews and reports of established hepatotoxins, new and expanded DILI registries and the continuing emphasis placed on genetic and other risk factors. Several new analyses of data generated from the US DILI Network are included.

EXPERT OPINION

The clinical usefulness of pharmacogenetic testing remains to be determined; the number of patients who must be tested is large and the overall risk of DILI is quite small. The role that dose and hepatic metabolism play in causing idiosyncratic DILI was reviewed; daily doses > 50 - 100 mg of medications with high lipophilicity appear to be most predictive of severe DILI, but not in all cases. Restricting access to paracetamol in certain parts of the UK continues to demonstrate a successful reduction in the number of acute liver failure cases and patients listed for liver transplant.

Ipilimumab in the treatment of metastatic melanoma: management of adverse events

Recently, "ipilimumab," an anti-cytotoxic T-lymphocyte antigen-4 (CTLA-4) monoclonal antibody, has been demonstrated to improve overall survival in metastatic melanoma. "CTLA-4" is an immune-checkpoint molecule that downregulates pathways of T-cell activation. Ipilimumab, by targeting CTLA-4, is able to remove the CTLA-4 inhibitory signal, allowing the immune system to react to cancer cells. Due to its immune-based mechanism of action, ipilimumab causes the inhibition of CTLA-4-mediated immunomodulatory effects, the enhancement of antitumor specific immune response mediated by the weakening of self-tolerance mechanisms while exacerbating the development of autoimmune diseases and immune-related adverse events, including dermatitis, hepatitis, enterocolitis, hypophysitis, and uveitis.