Gastrointestinal toxicity of immune checkpoint inhibitors: from mechanisms to management

Treatment options for immune-related adverse events associated with immune checkpoint inhibitors

The immunotherapy revolution with the use of immune checkpoint inhibitors (ICIs) started with the clinical use of the first ICI, ipilimumab, in 2011. Since then, the field of ICI therapy has rapidly expanded - with the FDA approval of 10 different ICI drugs so far and their incorporation into the therapeutic regimens of a range of malignancies. While ICIs have shown high anti-cancer efficacy, they also have characteristic side effects, termed immune-related adverse events (irAEs). These side effects hinder the therapeutic potential of ICIs and, therefore, finding ways to prevent and treat them is of paramount importance. The current protocols to manage irAEs follow an empirical route of steroid administration and, in more severe cases, ICI withdrawal. However, this approach is not optimal in many cases, as there are often steroid-refractory irAEs, and there is a potential for corticosteroid use to promote tumour progression. This review surveys the current alternative approaches to the treatments for irAEs, with the goal of summarizing and highlighting the best attempts to treat irAEs, without compromising anti-tumour immunity and allowing for rechallenge with ICIs after resolution of the irAEs.

New strategies in the diagnosis and treatment of immune-checkpoint inhibitor-mediated colitis

Immune-checkpoint inhibitor-mediated colitis (IMC) is an increasingly recognized adverse event in cancer immunotherapy, particularly associated with immune checkpoint inhibitors (ICIs) such as anti-cytotoxic T-lymphocyte antigen-4 and anti-programmed cell death protein-1 antibodies. As this revolutionary immunotherapy gains prominence in cancer treatment, understanding, diagnosing, and effectively managing IMC becomes paramount. IMC represents a unique challenge due to its immune-mediated nature and potential for severe complications. However, a precise picture of IMC pathophysiology is currently unavailable. Therefore, we aimed to summarize the existing data while acknowledging the need for further research. This comprehensive review explores the mechanisms underlying ICIs, gastrointestinal adverse effects, and, in particular, IMC's incidence, prevalence, and features. Our review also emphasizes the importance of recognizing IMC's distinct clinical and histopathological features to differentiate it from other forms of colitis. Furthermore, this paper highlights the urgent need for evolving diagnostic methods, therapeutic strategies, and a multidisciplinary approach to effectively manage IMC.

An Overview of Advances in Rare Cancer Diagnosis and Treatment

Cancer stands as the leading global cause of mortality, with rare cancer comprising 230 distinct subtypes characterized by infrequent incidence. Despite the inherent challenges in addressing the diagnosis and treatment of rare cancers due to their low occurrence rates, several biomedical breakthroughs have led to significant advancement in both areas. This review provides a comprehensive overview of state-of-the-art diagnostic techniques that encompass new-generation sequencing and multi-omics, coupled with the integration of artificial intelligence and machine learning, that have revolutionized rare cancer diagnosis. In addition, this review highlights the latest innovations in rare cancer therapeutic options, comprising immunotherapy, targeted therapy, transplantation, and drug combination therapy, that have undergone clinical trials and significantly contribute to the tumor remission and overall survival of rare cancer patients. In this review, we summarize recent breakthroughs and insights in the understanding of rare cancer pathophysiology, diagnosis, and therapeutic modalities, as well as the challenges faced in the development of rare cancer diagnosis data interpretation and drug development.

Enterocolitis and other immunotherapy and targeted therapy-related gastrointestinal manifestations: A review for gastroenterologist

New oncologic treatments, particularly immunotherapy (IT), have revolutionized the treatment of advanced-stage malignant tumors. Immune checkpoint inhibitors are the main form of IT and act by increasing T cell activity and the organism's immune response against neoplastic cells. Targeted therapy is another form of IT that acts by inhibiting oncogenes or inflammation signaling and tumor angiogenesis pathways. However, these mechanisms of tumor destruction can interfere with the host's immune self-tolerance or with the mechanisms of epithelial tissue repair and predispose to immune system-mediated adverse events that can affect multiple organs, including the digestive tract. The gastrointestinal manifestations of damage caused by IT can range from low-grade mucositis to ulceration, and in some cases, necrosis and perforation. Any part of the gastrointestinal tract can be affected, but there is greater involvement of the small bowel and colon, with a pattern similar to that seen in inflammatory bowel disease. The most common clinical manifestation is chronic diarrhea. The differential diagnosis includes enteropathogenic infections, especially those caused by opportunistic microorganisms; adverse drug reactions; and other inflammatory and malabsorption disorders. Treatment is guided by damage severity. Mild cases can be treated with antidiarrheals and rehydration in the outpatient setting; moderate cases with hospitalization, systemic steroids, and temporary suspension of IT; and severe cases with immunosuppressants or biologic agents and definitive suspension of IT.

Severe and refractory gastrointestinal toxicity due to immune checkpoint inhibitors: clinical experience in a tertiary referral hospital

INTRODUCTION

immune checkpoint inhibitors (ICI) are increasingly used to treat several types of cancer. These drugs lead to a wide range of toxicities. Immune-related gastrointestinal adverse events are common and potentially severe. In this manuscript, we recount the real clinical experience in a tertiary center.

METHODS

a retrospective and observational study was conducted in adult patients under ICI treatment. Included patients had been referred to the Gastrointestinal Service of Hospital Universitario Vall d'Hebron for evaluation of severe toxicities, from January 2017 to January 2020, for whom the clinical, epidemiological and evolutive data were collected.

RESULTS

a total of 18 patients were included. Fifty-five percent received anti-programmed cell death protein 1 (PD-1)/anti-programmed death-ligand 1 (anti PD-L1), 11 % received anti-cytotoxic T lymphocyte antigen 4 (CTLA-4) and 33 % received both treatments. The toxicities were manifested as enterocolitis, microscopic colitis and gastritis. Upper gastrointestinal endoscopy was performed in seven patients; all were proved to have histological changes on duodenum biopsies. Treatment was stopped in all patients and steroids were initiated. Sixty-six per cent achieved clinical remission with steroids. Five patients received anti-TNF treatment (infliximab). Only one of the five had responded. Two anti-TNF refractory patients received ustekinumab, with an appropriate clinical response. One patient received apheresis granulocyte as concomitant treatment. A patient with a steroid-dependent course started vedolizumab. Three patients had other immune-related adverse events.

CONCLUSION

gastrointestinal immune-related adverse events are acquiring a higher profile in daily practice and gastroenterologists play an even greater role in the management of these patients.

Immunotherapy in hematologic malignancies: achievements, challenges and future prospects

The immune-cell origin of hematologic malignancies provides a unique avenue for the understanding of both the mechanisms of immune responsiveness and immune escape, which has accelerated the progress of immunotherapy. Several categories of immunotherapies have been developed and are being further evaluated in clinical trials for the treatment of blood cancers, including stem cell transplantation, immune checkpoint inhibitors, antigen-targeted antibodies, antibody-drug conjugates, tumor vaccines, and adoptive cell therapies. These immunotherapies have shown the potential to induce long-term remission in refractory or relapsed patients and have led to a paradigm shift in cancer treatment with great clinical success. Different immunotherapeutic approaches have their advantages but also shortcomings that need to be addressed. To provide clinicians with timely information on these revolutionary therapeutic approaches, the comprehensive review provides historical perspectives on the applications and clinical considerations of the immunotherapy. Here, we first outline the recent advances that have been made in the understanding of the various categories of immunotherapies in the treatment of hematologic malignancies. We further discuss the specific mechanisms of action, summarize the clinical trials and outcomes of immunotherapies in hematologic malignancies, as well as the adverse effects and toxicity management and then provide novel insights into challenges and future directions.

Colitis induced by PD-1 inhibitor combined with platinum-containing dual drug chemotherapy in Lewis mice and its mechanism

Aims

To explore the occurrence and possible mechanism of colitis in Lewis mice treated with PD-1 inhibitor combined with platinum-containing dual drug chemotherapy.

Subjects and Methods

A Lewis lung cancer model of C57BL/6 mice was established, randomly divided into the treatment group (group C, PD-1 inhibitor + Carboplatin (CARB) + Pemetrexed (PEM)) and model group (group B, normal saline), and a control group (group A, normal saline) was set up. Observe the changes in tumor-free weight, tumor volume, disease activity index (DAI), colon histopathology, identify serum interleukin (IL)-10, interferon (IFN)-γ, the expression of claudin-1, and occludin mRNA in the colon in each animals.

Results

Compared with group A, the tumor-free weight of mice in B decreased (P < 0.001), the content of IL-10 in serum increased (P < 0.01), the content of IFN-γ in serum decreased (P < 0.01). Compared with group B, the transplanted tumor volume in C was reduced (P < 0.05), DAI scores of D4 (P < 0.001), and D7 (P < 0.001) were increased, colonic histopathology analysis showed that colitis occurred, serum IL-10 content was decreased (P < 0.05), IFN-γ content was increased (P < 0.05), and the mRNA expression of claudin-1 (P < 0.05) and occludin (P < 0.05) was reduced.

Conclusions

This treatment can inhibit the growth of transplanted tumors but will cause colitis in Lewis mice. The impairment of intestinal barrier function following administration cause an imbalance in the expression of pro-inflammatory and anti-inflammatory factors in the colon, thus causing colitis.

Subclinical Celiac Disease Unmasked by Immune Checkpoint Inhibitor Therapy

Immune checkpoint inhibitors (ICI) are antibodies that block immune checkpoint proteins from binding with their partner proteins on cancer cells, subsequently allowing cytotoxic T-cell-associated enhancement of antitumor responses. Although ICIs have become the standard of care for various malignancies, their use is often limited by unique immune-related adverse events, including dermatologic, endocrine, inflammatory, hepatic, and gastrointestinal events. Diarrhea and colitis are common lower gastrointestinal tract immune-related adverse events, however, only a few cases have reported the association between celiac disease (CD) and ICIs. We report here a case of a 75-year-old man with new onset CD after exposure to the cytotoxic T-lymphocyte-associated antigen-4 ICI, ipilimumab. Although ICI-induced CD is relatively rare, it is essential to consider it in a genetically susceptible patient undergoing treatment with ICI. Patients with known high susceptibility to CD, such as a family history of CD, or with the ancestry of high celiac penetrance (eg, Northern Europe, North Africa, etc), dermatitis herpetiformis, or chronic bowel symptoms, we feel should have celiac panel testing before initiating ICI therapy.

Gastrointestinal injury induced by immunomodulators: A review article

An increasing number of immunomodulators, either anti-inflammatory or immunity-enhancing, have brought about a revolutionary effect in the management of a variety of autoimmune disorders and malignancies. However, their ability to cause gastrointestinal (GI) injury and induce GI symptoms has been increasingly and unexpectedly recognized. GI injury associated with immunomodulators may demonstrate various histologic and endoscopic patterns. Optimal diagnosis and treatment require a multidisciplinary approach. This review aims to provide an overview of the literature on its pathogenesis, the clinical, endoscopic, and histologic features, and suggested approaches to manage these newly recognized immunomodulator-induced GI adverse effects (AEs). We also reviewed current biomarkers predictive of GI toxicity and potential risk factors to identify susceptible patients. In addition, these immune-mediated AEs were compared with inflammatory bowel disease, a well-documented form of inflammation-driven GI injury. We hope this review will raise awareness and vigilance among clinicians of these entities to increase early diagnosis and rapid referral to specialist care.

Gut microbiota, an emergent target to shape the efficiency of cancer therapy

It is now well-acknowledged that microbiota has a profound influence on both human health and illness. The gut microbiota has recently come to light as a crucial element that influences cancer through a variety of mechanisms. The connections between the microbiome and cancer therapy are further highlighted by a number of preclinical and clinical evidence, suggesting that these complicated interactions may vary by cancer type, treatment, or even by tumor stage. The paradoxical relationship between gut microbiota and cancer therapies is that in some cancers, the gut microbiota may be necessary to maintain therapeutic efficacy, whereas, in other cancers, gut microbiota depletion significantly increases efficacy. Actually, mounting research has shown that the gut microbiota plays a crucial role in regulating the host immune response and boosting the efficacy of anticancer medications like chemotherapy and immunotherapy. Therefore, gut microbiota modulation, which aims to restore gut microbial balance, is a viable technique for cancer prevention and therapy given the expanding understanding of how the gut microbiome regulates treatment response and contributes to carcinogenesis. This review will provide an outline of the gut microbiota's role in health and disease, along with a summary of the most recent research on how it may influence the effectiveness of various anticancer medicines and affect the growth of cancer. This study will next cover the newly developed microbiota-targeting strategies including prebiotics, probiotics, and fecal microbiota transplantation (FMT) to enhance anticancer therapy effectiveness, given its significance.

COLAR: open-label clinical study of IL-6 blockade with tocilizumab for the treatment of immune checkpoint inhibitor-induced colitis and arthritis

Background

Immune-related adverse events due to immune checkpoint inhibitors (ICIs) are not always effectively treated using glucocorticoids and it may negatively affect the antitumor efficacy of ICIs. Interventional studies of alternatives to glucocorticoids are lacking. We examined whether interleukin-6 blockade by tocilizumab reduced ICI-induced colitis and arthritis.

Patients and methods

Patients with solid cancer experiencing Common Terminology Criteria for Adverse Events (CTCAE v5.0) grade >1 ICI-induced colitis/diarrhea (n=9), arthritis (n=9), or both (n=2) were recruited and treated with tocilizumab (8 mg/kg) every 4 weeks until worsening or unacceptable toxicity. Patients were not allowed to receive systemic glucocorticoids and other immunosuppressive drugs within the 14-day screening period. The primary endpoint was clinical improvement of colitis and arthritis, defined as ≥1 grade CTCAE reduction within 8 weeks. Secondary endpoints were improvements and glucocorticoid-free remission at week 24; safety; radiologic, endoscopic, and histological changes; and changes in plasma concentrations of C reactive protein, cytokines (IL-6, IL-8, and IL-17), and YKL-40.

Results

Nineteen patients were available for efficacy analysis; one patient was excluded due to pancreatic insufficiency-induced diarrhea. Patients received treatment with pembrolizumab (n=10) or nivolumab (n=4) as monotherapy or ipilimumab and nivolumab (n=5) combined. Seven patients had been initially treated with glucocorticoids, and two of them also received infliximab. Ten patients continued ICI therapy during tocilizumab treatment. The primary endpoint was achieved in 15 of 19 (79%) patients. Additional one patient had ≥1 grade reduction at week 10, and another patient had stabilized symptoms. At week 24, ongoing improvement without glucocorticoids (n=12), including complete remission (n=10), was noted. Five patients had grades 3–4 treatment-related adverse events, which were manageable and reversible.

Conclusions

Tocilizumab showed promising clinical efficacy and a manageable safety profile in the treatment of ICI-induced colitis and arthritis. Our findings support the feasibility of randomized trials of immune-related adverse events.

Trial registration number

NCT03601611.

Management of immune checkpoint inhibitor in patients with cancer and pre-existing inflammatory bowel disease: Recommendations from the GETAID

BACKGROUND AND AIMS

There is no consensus on the management of immune checkpoint inhibitor (ICI) for treating cancer in patients with pre-existing inflammatory bowel disease (IBD). The Groupe d'Étude Thérapeutique des Affections Inflammatoires du tube Digestif (GETAID) aimed to provide recommendations on this topic.

METHODS

A dedicated working group performed a comprehensive expert-based review of the literature, generated clinical key question and shaped recommendations that were further voted for approval by the educational and scientific committees of the GETAID. Using consensus methods, treatment modalities were defined by vote.

RESULTS

Majority of patients with IBD in clinical remission can be treated with ICI after cancer diagnosis. The rate of relapse or immune-related diarrhoea or colitis upon ICI treatment is up to 39.8% and is maximal with ICI combination therapy compared to monotherapies. When starting ICI in a patient with IBD, it is recommended to assess disease activity and pursue ongoing maintenance therapy. In case of relapse or immune-related diarrhoea or colitis upon ICI treatment, treatment depends on grading of diarrhoea or colitis and may include corticosteroid therapy, infliximab and/or vedolizumab.

CONCLUSIONS

In the present publication, we provided recommendations, which may assist gastroenterologists, haematologists, and oncologists for a better management of patients with pre-existing IBD before and during cancer treatment with ICI.

Oral beclomethasone dipropionate is an effective treatment for immune checkpoint inhibitor induced colitis

INTRODUCTION

Systemic corticosteroids are the mainstay of treatment for immune checkpoint inhibitor induced (CPI) colitis but are associated with complications including life-threatening infection. The topically acting oral corticosteroid beclomethasone dipropionate (BD) is an effective treatment for mild to moderate flares of ulcerative colitis, and has fewer side effects than systemic corticosteroids. We hypothesized that BD would be an effective treatment for CPI-induced colitis.

METHODS

We performed a retrospective analysis of all patients who started BD for CPI-induced colitis at three UK cancer centers between November 2017 and October 2020. All patients underwent endoscopic assessment and biopsy. The initial regimen of BD was 5 mg once daily for 28 days. Data were collected from electronic patient records. Clinical outcomes were assessed at 28 days after initiation of treatment.

RESULTS

Twenty-two patients (14 male) with a median age of 64 (range 45-84) with CPI-induced colitis were treated with BD. At baseline, the median number of loose stools in a 24-hour period was six (common terminology criteria for adverse events, CTCAE grade diarrhea=2). Thirteen patients (59%) were dependent on systemic corticosteroids prior to starting BD. Baseline sigmoidoscopy showed moderate inflammation (Mayo Endoscopic Score (MES) = 2) in two patients (9%), mild inflammation (MES=1) in nine patients (41%) and normal findings (MES=0) in eleven patients (50%). Twenty patients (91%) had histopathological features of inflammation. All 22 patients (100%) had a clinical response to BD and 21 (95%) achieved clinical remission with a return to baseline stool frequency (CTCAE diarrhea=0). Ten patients (45%) had symptomatic relapse on cessation of BD, half within 7 days of stopping. All patients recaptured response on restarting BD. No adverse events were reported in patients treated with BD.

CONCLUSIONS

Topical BD represents an appealing alternative option to systemic immunosuppressive treatments to treat colonic inflammation. In this study, BD was effective and safe at inducing remission in CPI-induced colitis, which was refractory to systemic corticosteroids. Further randomized studies are needed to confirm these findings and determine the optimum dosing regimen.

Immune Checkpoint Inhibitor Rechallenge After Prior Immune Toxicity

OPINION STATEMENT

Immune checkpoint inhibitors (ICIs) have become an essential part of treatment for many cancer types. These monoclonal antibodies remove a critical negative regulatory signal that allows the immune system to recognize and destroy malignant cells that were previously undetectable. Unfortunately, their use has ushered in a whole new form of drug toxicity whereby the immune system attacks normal tissues in the body, referred to hereafter as immune-related adverse events (irAEs). irAEs are common and can result in treatment discontinuation, hospitalization, and death. When alternative modes of treatment are limited, or considered less efficacious, there may be a desire to resume treatment with ICIs after an irAE. Rechallenge with ICIs carries with it a heightened risk of subsequent toxicity, but with careful consideration and appropriate patient selection, this can be considered a reasonable approach.

Celiac Disease After Administration of Immune Checkpoint Inhibitors: A Case Report

Immune checkpoint inhibitors (ICI) reinvigorate the immune system to recognize and destroy tumor cells. Because of this biological mechanism, patients might develop autoimmune toxicities, notably in the digestive tract (most frequently, hepatitis or colitis). A 70-year-old man with relapsed mesothelioma was treated with nivolumab in 3rd line. He was hospitalized for watery and foul-smelling diarrhea. He underwent gastrointestinal endoscopy, showing duodenitis and villous atrophy and measurement of serum IgA antibodies to tissue transglutaminase (tTG-IgA+), leading to the diagnosis of ICI-induced celiac disease. He was treated with steroids, proton pump inhibitors, and a gluten-free diet. If ICI-induced celiac disease is rare in the literature, increasing reports suggest that celiac disease might represent an underestimated ICI toxicity. This case highlights the necessity of complementary investigation (including tTG-IgA and endoscopic biopsies) in patients with atypical digestive symptoms during immunotherapy.

Improvement of PD-1 Blockade Efficacy and Elimination of Immune-Related Gastrointestinal Adverse Effect by mTOR Inhibitor

During the past decades, immunotherapy, especially the antibody-mediated immune checkpoint blockade (ICB) has shown durable tumor inhibition and changed the paradigm of cancer treatment. However, a growing body of evidence suggests that ICB treatment induces severe immune-related adverse events (irAEs), and the side effect even leads to the discontinuation of lifesaving treatment. Here, we found that ICB treatment induces colitis in melanoma patients and promotes the infiltration of CD8⁺ effector T cells into colitic lesions. Further transcriptomic dissection indicated the PI3K-AKT-mTOR pathway was highly activated in CD8⁺ effector T cells of colitic lesions. Moreover, we developed a mouse melanoma model to recapitulate the gastrointestinal toxicity of anti-PD-1 treatment in clinical settings. Anti-PD-1 treatment significantly contributed to the infiltration of CD8⁺ T cells, and correspondingly induced severe enteritis. Immunohistochemistry experiments showed that the PI3K-AKT-mTOR pathway of T cells was activated by anti-PD-1 treatment. Blockade of the pathway with mTOR inhibitor sirolimus not only inhibits tumor growth but also suppresses the T cell infiltration in colitic lesions. More importantly, combination with sirolimus and anti-PD-1 synergistically inhibits tumor growth via inducing the immunogenic cell death of tumor cells in vivo. In summary, our research demonstrated the principle of mTOR inhibitor and anti-PD-1 combinatorial therapeutic regimen, which provided a novel therapeutic strategy for irAEs in clinics.

Nivolumab-induced exocrine pancreatic insufficiency

Immune checkpoint inhibition is the standard-of-care for many advanced cancers. Side effects of therapy may prevent optimal treatment of the cancer. Management of side effects is dominated by recommendations derived from oncological, not gastroenterological practice. We report a patient who developed pancreatic insufficiency during checkpoint inhibitor therapy with a programmed cell death receptor 1 inhibitor, nivolumab, which if not diagnosed would have prevented ongoing treatment. This is a problem which affects approximately 1 in 100 patients treated with this agent but is rarely recognised. Gastroenterologists need to be aware of the spectrum of gastrointestinal disorders which occur after immunotherapy to treat cancer.

Hepatic immune-mediatedadverseeffects of immune checkpoint inhibitors: analysis of real-life experience

INTRODUCTION AND OBJECTIVES

Immune Checkpoint Inhibitors (ICI) have shifted the paradigm of cancer therapy treatment. Despite their efficacy, ICIs may induce immune-related adverse events (irAE), which can affect various organs, namely the liver. This study intends to perform a comprehensive clinical description of the hepatic irAEs associated with ICI in a Portuguese population of a tertiary hospital centre.

MATERIALS AND METHODS

A retrospective analysis of patients who developed immune-mediated liver injury (IMLI), among a cohort of patients treated with ICIs between March 15^th of 2015 and December 15^th of 2019 in a tertiary hospital. We used both Common Terminology Criteria for Adverse Events (CTCAE) and Drug-Induced Liver Injury Network (DILIN) criteria to define liver injury.

RESULTS

Among 151 patients, eight (5.3%) patients developed liver injury grade ≥3, of which five had hepatic metastasis. As such, only 3 cases were classified as IMLI. All IMLI presented with cholestasis pattern; the median duration from ICI initiation to IMLI was 84 days and/or 4 ICI cycles; one patient registered IMLI one month after nivolumab suspension; all were treated with steroids and one was successfully submitted to ICI re-challenge; a favourable outcome was seen in all patients; the median time to hepatic biochemistries normalization was 150 days. Among 10 patients with previous hepatic conditions, only one developed liver injury grade 2.

CONCLUSIONS

Clinically significant ICI-related hepatotoxicity was uncommon; Immune-mediated liver injury may present a cholestatic pattern predominance. There was a low rate of liver injury of any kind in patients with previous hepatic disease while on ICI.

Immune Checkpoint Inhibitor-Induced Gastrointestinal Toxicity: The Opinion of a Gastroenterologist

Immune checkpoint inhibitors (ICIs) are currently an important component of the standard first-line treatment for many neoplasms. Some guidelines recommend ICIs as adjuvant treatment. With their increased use, the incidence of associated immune-mediated adverse reactions will also increase. A significant proportion of these reactions is represented by immune-mediated diarrhea or colitis, hepatitis, and immune-mediated pancreatic damage. The present review aims to highlight the new trends related to the diagnosis and treatment of these adverse effects depending on their degree, from the perspective of the gastroenterologist. To accomplish this, a literature search was performed, and 30 publications were considered relevant (according to the Population, Intervention, Comparison, Outcomes, and Study [PICOS] criteria). The information about each of the three toxicities in this paper was structured in two categories such as differential diagnosis and treatment. This review aims not only to increase awareness of these side effects in the gastroenterology community but also to promote the development of new treatment guidelines with contributions from gastroenterologists.

Nivolumab dose escalation triggered immune checkpoint inhibitor-induced colitis after 147 weeks of prolonged stable use in a patient with lung cancer: a case report

A 56-year-old man with advanced lung adenocarcinoma presented to the emergency department with a 6-day history of diarrhea. He was treated for lung cancer with nivolumab 3 mg/kg (144 mg/body) every 2 weeks (Q2W), followed by an increase to 240 mg Q2W for 147 weeks, for a total of 69 administrations. His dose was then increased to 480 mg/body every four weeks (Q4W) 12 days before his presentation. Clostridioides difficile toxin, cytomegalovirus antigenemia, and stool bacterial cultures were negative. Colonoscopy revealed diffusely edematous granular mucosa with mucosal redness, exudates, loss of vascular pattern, and aphtha throughout the colon but no ulcers. We diagnosed the patient with immune checkpoint inhibitor-induced colitis. We started prednisolone at a dose of 60 mg/day. His symptoms gradually improved, and he recovered without diarrhea on day ten after hospitalization. After prednisolone tapering, his symptoms did not worsen. Colonoscopy showed significant improvement on day 29, and the diffuse redness disappeared. The patient did not experience subsequent recurrence of diarrhea. He had no progression of lung cancer despite the termination of nivolumab for seven months. Here, we report a case of lung cancer in which nivolumab dose escalation after prolonged stable use triggered immune checkpoint inhibitor-induced colitis.

Risk of selected gastrointestinal toxicities in metastatic renal cell carcinoma patients treated with immuno-TKI combinations: a meta-analysis

OBJECTIVE

Recent years have registered the advent of novel treatment options for metastatic renal cell carcinoma (mRCC), including combination therapies with immune checkpoint inhibitors (ICIs) and tyrosine kinase inhibitors (TKIs). Immuno-TKI combinations have been suggested to improve clinical outcomes but may also result in increased toxicity, including gastrointestinal (GI) adverse events.

METHODS

Herein, we performed a meta-analysis aimed at comparing the risk of certain GI toxicities in mRCC patients treated with immuno-TKI combinations versus sunitinib monotherapy. Overall, four phase III trials (KEYNOTE-426, JAVELIN Renal 101, CheckMate 9ER, CLEAR) involving 3059 mRCC patients were available.

RESULTS

The meta-analysis suggested an increased risk of all-grade diarrhea, grade 3-4 diarrhea and grade 3-4 decreased appetite in patients treated with immuno-TKI combinations. Conversely, an apparently higher risk of all-grade nausea was observed in the sunitinib group.

CONCLUSION

The meta-analysis suggested that immuno-TKI combinations are associated with higher risk of GI toxicities compared with sunitinib. Beyond the efficacy of immuno-TKI combinations in mRCC patients, careful consideration should be given to treatment-related adverse events, including GI toxicities. Early recognition and treatment are critical to maximize recovery.

Alterations in DNA damage response and repair genes as potential biomarkers for immune checkpoint blockade in gastrointestinal cancer

Objective:

Immune checkpoint inhibitors (ICIs) have achieved remarkable results in cancer treatments. However, there is no effective predictive biomarker for gastrointestinal (GI) cancer.

Methods:

We conducted integrative analyses of the genomic and survival data of ICI-treated GI cancer patients from the Memorial Sloan Kettering Cancer Center cohort (MSK-GI, n = 227), the Janjigian cohort (n = 40), and the Peking University Cancer Hospital & Institute cohort (PUCH, n = 80) to determine the possible associations between DNA damage response and repair (DDR) gene mutations and clinical outcomes. Data from The Cancer Genome Atlas database were analyzed to determine the possible correlations between DDR gene mutations and the tumor microenvironment.

Results:

In the MSK cohort, the presence of ≥ 2 DDR gene mutations was correlated with prolonged overall survival (OS). The Janjigian and PUCH cohorts further confirmed that subgroups with ≥ 2 DDR gene mutations displayed a prolonged OS and a higher durable clinical benefit. Furthermore, the DDR gene mutation load could be considered as an independent prognostic factor, and exhibited a potential predictive value for survival in GI cancer patients treated with ICIs. Mechanistically, we showed that the presence of ≥ 2 DDR gene mutations was correlated with higher levels of tumor mutation burden, neoantigen, and T cell infiltration.

Conclusions:

The DDR gene mutation status was correlated with favorable clinical outcomes in GI cancer patients receiving ICIs, which could serve as a potential biomarker to guide patient selection for immunotherapy.

Epigenetic mechanisms of liver tumor resistance to immunotherapy

Hepatocellular carcinoma (HCC) is the most common primary liver tumor, which stands fourth in rank of cancer-related deaths worldwide. The incidence of HCC is constantly increasing in correlation with the epidemic in diabetes and obesity, arguing for an urgent need for new treatments for this lethal cancer refractory to conventional treatments. HCC is the paradigm of inflammation-associated cancer, since more than 80% of HCC emerge consecutively to cirrhosis associated with a vast remodeling of liver microenvironment. In the recent decade, immunomodulatory drugs have been developed and have given impressive results in melanoma and later in several other cancers. In the present review, we will discuss the recent advancements concerning the use of immunotherapies in HCC, in particular those targeting immune checkpoints, used alone or in combination with other anti-cancers agents. We will address why these drugs demonstrate unsatisfactory results in a high proportion of liver cancers and the mechanisms of resistance developed by HCC to evade immune response with a focus on the epigenetic-related mechanisms.

Approach to the adult patient with chronic diarrhea: A literature review

Chronic diarrhea is defined by symptoms lasting longer than 4 weeks. It is a common problem that affects up to 5% of the adult population. Different pathophysiologic mechanisms involve numerous causes, including drug side effects, postoperative anatomic and physiologic alterations, intestinal and colonic wall abnormalities, inflammatory or malabsorption causes, pancreatobiliary diseases, and functional or gut-brain axis disorders associated with dysbiosis or gastrointestinal motility alterations. Due to such a broad differential diagnosis, it is important to categorize chronic diarrhea into five main groups: drug side effect, postoperative, postinfectious, malabsorptive, inflammatory, and functional. The present review is a narrative analysis of the diagnostic approach, emphasizing key aspects of the clinical history, the utility of biomarkers (in breath, stool, urine, and serology) and malabsorption and motility tests, the role of radiologic and endoscopic studies, and the most common histologic findings. A diagnostic algorithm aimed at determining etiology and personalizing therapy is also proposed.

Checkpoint Inhibitor Colitis Shows Drug-Specific Differences in Immune Cell Reaction That Overlap With Inflammatory Bowel Disease and Predict Response to Colitis Therapy

OBJECTIVES

Checkpoint inhibitor (CPI)-associated colitis can limit therapy and has resemblance to inflammatory bowel disease (IBD). Studies exploring mechanistic similarities between these colitides are limited, yet therapeutic targets for either disorder could emerge from shared pathophysiology.

METHODS

The morphology and inflammatory content of colonic biopsy specimens from anti-CTLA-4 and anti-PD-1/PD-L1 antibody-treated patients with CPI colitis were compared with initial biopsy specimens from patients with IBD. Predictors of the need for infliximab were sought in CPI patients.

RESULTS

Biopsy specimens from CPI patients showed significantly lower chronicity scores and similar activity scores compared with patients with IBD. Anti-CTLA-4 and IBD groups showed equivalent CD8, CD4, PD-1, and PD-L1 expression, while FoxP3 scores were lower and CD68 scores were higher in anti-CTLA-4 compared with IBD biopsy specimens. Anti-PD-1/PD-L1 group had lower scores for CD8, CD4, and PD-1 and equivalent scores for FoxP3, PD-L1, and CD68 compared with IBD. Anti-CTLA-4 biopsy specimens had higher scores for CD8, PD-1, PD-L1, and CD68 than anti-PD-1/PD-L1 biopsy specimens. CD8/FoxP3 ratios and CD68 scores were higher among CPI patients requiring infliximab therapy for colitis compared with those responding to steroids.

CONCLUSIONS

The proinflammatory immune phenotype of anti-CTLA-4-associated colitis has significant overlap with IBD. CD8/FoxP3 ratios may predict therapeutic response in CPI-associated colitis.

Association of Antibiotic Exposure With Survival and Toxicity in Patients With Melanoma Receiving Immunotherapy

BACKGROUND

Gut microbial diversity is associated with improved response to immune checkpoint inhibitors (ICI). Based on the known detrimental impact that antibiotics have on microbiome diversity, we hypothesized that antibiotic receipt prior to ICI would be associated with decreased survival.

METHODS

Patients with stage III and IV melanoma treated with ICI between 2008 and 2019 were selected from an institutional database. A window of antibiotic receipt within 3 months prior to the first infusion of ICI was prespecified. The primary outcome was overall survival (OS), and secondary outcomes were melanoma-specific mortality and immune-mediated colitis requiring intravenous steroids. All statistical tests were two-sided.

RESULTS

There were 568 patients in our database of which 114 received antibiotics prior to ICI. Of the patients, 35.9% had stage III disease. On multivariable Cox proportional hazards analysis of patients with stage IV disease, the antibiotic-exposed group had statistically significantly worse OS (hazard ratio [HR] = 1.81, 95% confidence interval [CI] = 1.27 to 2.57; P <.001). The same effect was observed among antibiotic-exposed patients with stage III disease (HR = 2.78, 95% CI = 1.31 to 5.87; P =.007). When limited to only patients who received adjuvant ICI (n = 89), antibiotic-exposed patients also had statistically significantly worse OS (HR = 4.84, 95% CI = 1.09 to 21.50; P =.04). The antibiotic group had a greater incidence of colitis (HR = 2.14, 95% CI = 1.02 to 4.52; P =.046).

CONCLUSION

Patients with stage III and IV melanoma exposed to antibiotics prior to ICI had statistically significantly worse OS than unexposed patients. Antibiotic exposure was associated with greater incidence of moderate to severe immune-mediated colitis. Given the large number of antibiotics prescribed annually, physicians should be judicious with their use in cancer populations likely to receive ICI.

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.

Approach to the adult patient with chronic diarrhea: a literature review

Chronic diarrhea is defined by symptoms lasting longer than 4 weeks. It is a common problem that affects up to 5% of the adult population. Different pathophysiologic mechanisms involve numerous causes, including drug side effects, postoperative anatomic and physiologic alterations, intestinal and colonic wall abnormalities, inflammatory or malabsorption causes, pancreatobiliary diseases, and functional or gut-brain axis disorders associated with dysbiosis or gastrointestinal motility alterations. Due to such a broad differential diagnosis, it is important to categorize chronic diarrhea into five main groups: drug side effect, postoperative, postinfectious, malabsorptive, inflammatory, and functional. The present review is a narrative analysis of the diagnostic approach, emphasizing key aspects of the clinical history, the utility of biomarkers (in breath, stool, urine, and serology) and malabsorption and motility tests, the role of radiologic and endoscopic studies, and the most common histologic findings. A diagnostic algorithm aimed at determining etiology and personalizing therapy is also proposed.

Immunosuppressive Nanoparticles for Management of Immune-Related Adverse Events in Liver

Immune checkpoint blockade (ICB) therapy has been considered as an effective way to boost immune cells to recognize and attack tumors. However, side effects known as immune-related adverse events (irAEs) should be carefully managed. Here, we engineer immunosuppressive nanoparticles by coating PD-L1 overexpressed mesenchymal stem cells (MSCs) plasma membrane on poly lactic-co-glycolic acid nanoparticles (MSC-PD-L1⁺ NPs) for managing and reducing irAEs induced by immune checkpoint inhibitors. The nanoparticles can enrich at liver site after intravenous administration. In the high dose of anti-PD-L1 mAb-induced irAEs clinically relevant mouse model, a low dose of MSC-PD-L1⁺ NPs (2 mg/kg) sufficiently rescues hepatitis by inactivating T cells and macrophages in the liver tissue. More intriguingly, due to the dose threshold for nanoparticles to the tumor site, we unexpectedly find that the injected NPs do not affect the efficiency of ICB therapy to inhibit solid tumor growth. Such a strategy shows potential for managing the various cancer immunotherapy associated irAEs in clinical applications.

Programmed Death Ligand 1-Expressing Classical Dendritic Cells MitigateHelicobacter-Induced Gastritis

BACKGROUND & AIMS

Helicobacter pylori has been reported to modulate local immune responses to colonize persistently in gastric mucosa. Although the induced expression of programmed cell death ligand 1 (PD-L1) has been suggested as an immune modulatory mechanism for persistent infection of H pylori, the main immune cells expressing PD-L1 and their functions in Helicobacter-induced gastritis still remain to be elucidated.

METHODS

The blockades of PD-L1 with antibody or PD-L1-deficient bone marrow transplantation were performed in Helicobacter-infected mice. The main immune cells expressing PD-L1 in Helicobacter-infected stomach were determined by flow cytometry and immunofluorescence staining. Helicobacter felis or H pylori-infected dendritic cell (DC)-deficient mouse models including Flt3-/-, Zbtb46-diphtheria toxin receptor, and BDCA2-diphtheria toxin receptor mice were analyzed for pathologic changes and colonization levels. Finally, the location of PD-L1-expressing DCs and the correlation with H pylori infection were analyzed in human gastric tissues using multiplexed immunohistochemistry.

RESULTS

Genetic or antibody-mediated blockade of PD-L1 aggravated Helicobacter-induced gastritis with mucosal metaplasia. Gastric classical DCs expressed considerably higher levels of PD-L1 than other immune cells and co-localized with T cells in gastritis lesions from Helicobacter-infected mice and human beings. H felis- or H pylori-infected Flt3-/- or classical DC-depleted mice showed aggravated gastritis with severe T-cell and neutrophil accumulation with low bacterial loads compared with that in control mice. Finally, PD-L1-expressing DCs were co-localized with T cells and showed a positive correlation with H pylori infection in human subjects.

CONCLUSIONS

The PD-1/PD-L1 pathway may be responsible for the immune modulatory function of gastric DCs that protects the gastric mucosa from Helicobacter-induced inflammation, but allows persistent Helicobacter colonization.

Systemic adverse effects and toxicities associated with immunotherapy: A review

Immunotherapy is rapidly evolving secondary to the advent of newer immunotherapeutic agents and increasing approval of the current agents by the United States Food and Drug Administration to treat a wide spectrum of cancers. Immunotherapeutic agents have gained immense popularity due to their tumor-specific action. Immunotherapy is slowly transforming into a separate therapeutic entity, and the fifth pillar of management for cancers alongside surgery, radiotherapy, chemotherapy, and targeted therapy. However, like any therapeutic entity it has its own adverse effects. With the increasing use of immuno-therapeutic agents, it is vital for physicians to acquaint themselves with these adverse effects. The aim of this review is to investigate the common systemic adverse effects and toxicities associated with the use of different classes of immunotherapeutic agents. We provide an overview of potential adverse effects and toxicities associated with different classes of immunotherapeutic agents organized by organ systems, as well as an extensive discussion of the current recommendations for treatment and clinical trial data. As we continue to see increasing usage of these agents in clinical practice, it is vital for physicians to familiarize themselves with these effects.

Immune Checkpoint Inhibitor-Induced Upper Gastrointestinal Tract Inflammation Shows Morphologic Similarities to, but Is Immunologically Distinct From, Helicobacter pylori Gastritis and Celiac Disease

CONTEXT.—

Immune checkpoint inhibitor (CPI) therapies are associated with multi-organ immune-related adverse events. Although colonic mucosal changes have been described, inflammatory changes incited by CPIs in the upper gastrointestinal tract have not been well characterized.

OBJECTIVE.—

To investigate morphologic and immunologic changes incited by CPI therapy in the upper gastrointestinal tract.

DESIGN.—

We compared the morphology and immune cell phenotype of gastric and duodenal biopsies from patients treated with anti-cytotoxic T-lymphocyte associated protein 4 (CTLA-4) or anti-programmed death receptor-1/programmed death ligand-1 (PD-1/PD-L1) antibodies with biopsies from patients with Helicobacter pylori gastritis, patients with celiac disease, and normal controls.

RESULTS.—

Gastric biopsies from patients on CPIs showed chronic gastritis mimicking H pylori gastritis. However, CPI gastritis demonstrated greater numbers of CD8+ intraepithelial lymphocytes, less lamina propria inflammation, fewer plasma cells and CD20+ B cells, fewer lymphoid aggregates, and reduced CD4:CD8 ratio in both the lamina propria and the epithelial layer. There were no differences between anti-CTLA-4 and anti-PD-1/PD-L1 gastritis, except for more lymphoid aggregates in anti-PD-1/PD-L1 gastritis. Duodenal biopsies from patients on CPIs revealed chronic duodenitis with villous blunting, mimicking celiac disease. Compared with celiac disease, CPI duodenitis demonstrated higher prevalence of neutrophilic infiltrates and erosions, increased lamina propria CD3 and CD8 T cells, and reduced CD4:CD8 ratio. Upper gastrointestinal biopsies were more inflamed than concomitant colonic biopsies in the majority of patients.

CONCLUSIONS.—

The morphologic and immunophenotypic distinctions between CPI-associated upper gastrointestinal injuries and common infectious and autoimmune diseases may provide useful discriminators when clinicians are confronted with gastric and duodenal inflammatory changes in patients receiving CPI therapy.

The FOCCUS study: a prospective evaluation of the frequency, severity and treatable causes of gastrointestinal symptoms during and after chemotherapy

BACKGROUND

The underlying mechanisms of chemotherapy-induced gastrointestinal (GI) symptoms are poorly researched. This study characterised the nature, frequency, severity and treatable causes for GI symptoms prospectively in patients undergoing chemotherapy for GI malignancy.

METHODS

Patients receiving chemotherapy for a GI malignancy were assessed pre-chemotherapy, then monthly for 1 year using the Gastrointestinal Symptom Rating Scale, a validated patient-reported outcome measure. Patients with new, troublesome GI symptoms were offered investigations to diagnose the cause(s). Their oncologist was alerted when investigations were abnormal.

RESULTS

A total of 241 patients, 60% male, median age 63 years (range 30-88), were enrolled; 122 patients were withdrawn, 93%, because of progressive disease or death. During the study, > 20% patients reported chronic faecal incontinence and > 10% reported moderate or severe problems with taste, dysphagia, belching, heartburn, early satiety, appetite, nausea, abdominal cramps, peri-rectal pain, rectal flatulence, borborygmi, urgency of defecation or tenesmus. Thirty percent reported continuing passage of hard stools and 30% on-going diarrhoea. Moderate or severe fatigue affected 40% participants at its peak and persisted in 15% at 1 year. Toxicity dictated change in chemotherapy for 13-29% patients/month. Common Terminology Criteria for Adverse Events underestimated gastrointestinal morbidity. Pre-chemotherapy screening identified previously undiagnosed pathology: exocrine pancreatic insufficiency (9%), vitamin B12 deficiency (12%) and thyroid dysfunction (20%). Patients often refused investigations to diagnose their chemotherapy-induced symptoms; however, for every three investigations performed, one treatable cause was diagnosed: particularly small intestinal bacterial overgrowth (54%), bile acid malabsorption (43%), previously not described after chemotherapy, and unsuspected urinary tract infection (17%).

CONCLUSIONS

Patients undergoing chemotherapy for GI malignancy commonly have difficult GI symptoms requiring active management which does not occur routinely. The underlying causes for these symptoms are often treatable or curable. Randomised trials are urgently needed to show whether timely investigation and treatment of symptoms improve quality of life and survival.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02121626.

Toxicities from immunotherapy: From clinical trials to real-world clinical practice

In recent years, immunotherapy has become an important pillar of cancer treatment, with high response rates regardless of tumour histology or baseline mutations. However, immune activation associated with check-point inhibitors is not selective and a large variety of immune-related adverse events have been associated with anti-PD1, anti-PD-1/L-1 and anti-CTLA-4 agents. Though diagnosis and treatment of these toxicities have been established according to the recommendations from clinical trials and in line with the autoimmune disorders that they mimic, increasing real-world data is coming up showing that these adverse events may have differential characteristics and management, especially in terms of the use of corticoids, second-line treatments, salvage therapy for life-threatening cases and reintroduction of immunotherapy. Herein we present a comprehensive review of current recommendations and real-world data on the main immune-related adverse events of immunotherapy.

Gastrointestinal Adverse Effects of Immunotherapeutic Agents: A Systematic Review

The utilization of immunotherapy is increasing to the point of becoming the fifth pillar of management alongside surgical intervention, chemotherapy, radiotherapy and targeted therapy. However, gastrointestinal adverse effects and toxicities have been frequently cited with its use. As per literature, the most common adverse effect of immune checkpoint inhibitors is watery and non-bloody diarrhea. Adoptive cell therapy can lead to delayed, on-target but off-tumor adverse effects which are unknown and may be life-threatening. The use of anti-angiogenic monoclonal antibodies can lead to bowel perforations, whereas epidermal growth factor receptor inhibitors and anti-HER2 agents are frequently associated with diarrhea. Minimal adverse effects have been associated with therapeutic cancer vaccines; however, additional studies are needed to determine their efficacy and potential toxicities. To provide an in-depth review of the gastrointestinal side effects of immunotherapeutic agents, we performed a thorough literature search using multiple online search engines such as PubMed, Google Scholar and Ovid MEDLINE, along with a review of the guidelines from the United States Food and Drug Administration (FDA) and the Cancer Research Institute on immunotherapy. In this systematic review, we detail the gastrointestinal adverse effects of immunotherapy and describe their management. With the advent of newer immunotherapeutic agents and the consistent approval of current agents by FDA for a wide spectrum of cancers, it is vital for physicians to familiarize themselves with their adverse effects for prompt diagnosis and early intervention to decrease adverse outcomes.

Clinical relevance of intestinal barrier dysfunction in common gastrointestinal diseases

The intestinal barrier is a complex and well-controlled physiological construct designed to separate luminal contents from the bowel wall. In this review, we focus on the intestinal barrier’s relationship with the host’s immune system interaction and the external environment, specifically the microbiome. The bowel allows the host to obtain nutrients vital to survival while protecting itself from harmful pathogens, luminal antigens, or other pro-inflammatory factors. Control over barrier function and the luminal milieu is maintained at the biochemical, cellular, and immunological level. However, disruption to this highly regulated environment can cause disease. Recent advances to the field have progressed the mechanistic understanding of compromised intestinal barrier function in the context of gastrointestinal pathology. There are numerous examples where bowel barrier dysfunction and the resulting interaction between the microbiome and the immune system has disease-triggering consequences. The purpose of this review is to summarize the clinical relevance of intestinal barrier dysfunction in common gastrointestinal and related diseases. This may help highlight the importance of restoring barrier function as a therapeutic mechanism of action in gastrointestinal pathology.

Medication-specific variations in morphological patterns of injury in immune check-point inhibitor-associated colitis

AIMS

A varied spectrum of histopathological changes has been associated with immune checkpoint inhibitor (ICI) colitis. This study was performed to evaluate the prevalence of different histopathological patterns of injury in patients with ICI colitis and their association with specific immune check-point inhibitors.

METHODS AND RESULTS

Biopsies from patients with clinically and histologically confirmed ICI colitis were reviewed blindly to determine the predominant pattern of injury and to quantitate discrete histological parameters using the Geboes score. Paneth cell metaplasia, intraepithelial lymphocytes, abnormal subepithelial collagen and degree of crypt epithelial apoptosis was also recorded. A total of 86 patients with ICI colitis (ipilimumab, n = 14; ipilimumab + nivolumab, n = 29; nivolumab, n = 20 and pembrolizumab, n = 23) were included. The patterns of injury identified included diffuse active colitis (n = 22), chronic active colitis (n = 22), lymphocytic colitis (LC, n = 16), collagenous colitis (CC, n = 14), graft-versus-host disease-like colitis (n = 7) and mixed colitis (n = 5). Patients on ipilimumab were more likely to have a diffuse active colitis pattern without features of chronicity (P < 0.01) and less likely to have LC (P < 0.05) compared to other ICIs. LC and CC were more common in patients on nivolumab and pembrolizumab relative to other groups (P < 0.05). Chronic active colitis was most frequent in nivolumab patients (P < 0.05), and these patients had received more ICI doses and had been on ICI treatment longer compared to other treatment groups.

CONCLUSIONS

ICI colitis should be considered in the differential diagnosis of all the common inflammatory patterns of colitis and shows medication specific differences in patterns of injury.

Immune-related adverse events of a PD-L1 inhibitor plus chemotherapy versus a PD-L1 inhibitor alone in first-line treatment for advanced non-small cell lung cancer: A meta-analysis of randomized control trials

BACKGROUND

The addition of chemotherapy to a programmed death 1/programmed death ligand 1 (PD-L1) inhibitor is a more effective option as a first-line treatment for advanced non-small cell lung cancer (NSCLC). It might also inhibit an overactive immune response and thereby reduce immune-related adverse events (irAEs). This meta-analysis assessed the rate of irAEs with a PD-(L)1 inhibitor plus chemotherapy (I+C) versus a PD-(L)1 inhibitor alone (I) and evaluated the indirect relative risk (RR) of I+C versus I.

METHODS

The protocol of this study was registered with PROSPERO (CRD42020139923). The pooled rates of irAEs at different grades were calculated by a single-arm meta-analysis weighted by sample size, and RRs were determined by direct meta-analysis and indirect treatment comparison.

RESULTS

Overall, I+C had a lower rate of grade 3 or higher irAEs than I (7.1% vs 10.6%; indirect RR, 0.516; 95% confidence interval [CI], 0.291-0.916), although irAEs of any grade were similar. The rate of pneumonitis with I+C was lower than the rate with I for any grade (5.9% vs 7.1%; indirect RR, 0.217; 95% CI, 0.080-0.588) and for grade 3 or higher. In the endocrine system, I+C was associated with a lower overall ratein comparison with I (16.1% vs 20.1%; indirect RR, 0.260; 95% CI, 0.120-0.564), whereas irAEs of the digestive system were similar with I+C and I. In other systems, I+C decreased the rate of skin reactions, including rash, in comparison with I (10.4% vs 12.9%; indirect RR, 0.474; 95% CI, 0.299-0.751). The rate of grade 3 or higher skin reactions (excluding rash) also decreased with I+C versus I (1.1% vs 2.0%) with an indirect RR of 0.158 (95% CI, 0.032-0.765), whereas other included irAEs were similar.

CONCLUSIONS

In comparison with a PD-(L)1 inhibitor alone, a combination with chemotherapy for the first-line treatment of NSCLC decreased the rates of most irAEs, such as pneumonitis and endocrine and skin reactions, and the overall rate.

LAY SUMMARY

In the first-line treatment of advanced non-small cell lung cancer (NSCLC), the addition of chemotherapy to a programmed death 1/programmed death ligand 1 (PD-(L)1) inhibitor is a more effective option. Adding chemotherapy might reduce immune-related adverse events (irAEs). Thus, this article assesses the rate of irAEs with a PD-(L)1 inhibitor plus chemotherapy (I+C) in comparison with a PD-(L)1 inhibitor alone (I) and evaluates the indirect relative risk (RR) with I+C versus I. The key finding is that in comparison with a PD-(L)1 inhibitor alone, a combination with chemotherapy for the first-line treatment of NSCLC decreases the rates of most irAEs, such as pneumonitis and endocrine and skin reactions, and the overall rate.

Antibiotics, cancer risk and oncologic treatment efficacy: a practical review of the literature

Antibiotics have been extensively used to treat infectious diseases over the past century and have largely contributed to increased life expectancy over time. However, antibiotic use can impose profound and protracted changes to the diversity of the microbial ecosystem, affecting the composition of up to 30% of the bacterial species in the gut microbiome. By modifying human microbiota composition, antibiotics alter the action of several oncologic drugs, potentially leading to decreased efficacy and increased toxicities. Whether antibiotics interfere with cancer therapies or even increase the risk of cancer development has been under investigation, and no randomised trials have been conducted so far. The aim of the current review is to describe the possible effects of antibiotic therapies on different oncologic treatments, especially immunotherapies, and to explore the link between previous antibiotics use and the development of cancer.

Expert Consensus for Treating Cancer Patients During the Pandemic of SARS-CoV-2

The sudden pandemic of SARS-Cov-2 (also known as novel coronavirus disease 2019, COVID-19) poses a severe threat to hundreds of millions of lives in the world. The complete cure of the virus largely relies on the immune system, which becomes particularly a challenge for the cancer subjects, whose immunity is generally compromised. However, in a constant evolving situation, the clinical data on the prevalence of SARS-Cov-2 for cancer patients is still limited. On top of a wide range of medical references and interim guidelines including CDC, NCI, ASCO, ESMO, NCCN, AACR, ESMO, and the National Health Commission of China, etc., we formed into a guideline based on our experience in our specialized cancer hospital in Wuhan, the originally endemic center of the virus. Furthermore, we formulated an expert consensus which was developed by all contributors from different disciplines after fully discussion based on our understanding and analysis of limited information of COVID-19. The consensus highlighted a multidisciplinary team diagnostic model with assessment of the balance between risks and benefits prior to treatment, individualizing satisfaction of patients' medical needs, and acceptability in ethics and patients' socio-economic conditions.

Thymosin α1 protects from CTLA-4 intestinal immunopathology

This study demonstrates that Tα1 protects mice from anti–CTLA-4–induced colitis and sustains its antitumor activity, thus suggesting that Tα1 may be used in combination protocols.

The advent of immune checkpoint inhibitors has represented a major boost in cancer therapy, but safety concerns are increasingly being recognized. Indeed, although beneficial at the tumor site, unlocking a safeguard mechanism of the immune response may trigger autoimmune-like effects at the periphery, thus making the safety of immune checkpoint inhibitors a research priority. Herein, we demonstrate that thymosin α1 (Tα1), an endogenous peptide with immunomodulatory activities, can protect mice from intestinal toxicity in a murine model of immune checkpoint inhibitor–induced colitis. Specifically, Tα1 efficiently prevented immune adverse pathology in the gut by promoting the indoleamine 2,3-dioxygenase (IDO) 1–dependent tolerogenic immune pathway. Notably, Tα1 did not induce IDO1 in the tumor microenvironment, but rather modulated the infiltration of T-cell subsets by inverting the ratio between CD8⁺ and Treg cells, an effect that may depend on Tα1 ability to regulate the differentiation and chemokine expression profile of DCs. Thus, through distinct mechanisms that are contingent upon the context, Tα1 represents a plausible candidate to improve the safety/efficacy profile of immune checkpoint inhibitors.

British Society of Gastroenterology endorsed guidance for the management of immune checkpoint inhibitor-induced enterocolitis

Immune checkpoint inhibitors are a novel class of cancer treatment that have improved outcomes for a subset of cancer patients. They work by antagonising inhibitory immune pathways, thereby augmenting immune-mediated antitumour responses. However, immune activation is not cancer-specific and often results in the activation of immune cells in non-cancer tissues, resulting in off-target immune-mediated injury and organ dysfunction. Diarrhoea and gastrointestinal tract inflammation are common and sometimes serious side-effects of this type of therapy. Prompt recognition of gastrointestinal toxicity and, in many cases, rapid institution of anti-inflammatory or biologic therapy (or both) is required to reverse these complications. Management of organ-specific complications benefits from multidisciplinary input, including engagement with gastroenterologists for optimal management of immune checkpoint inhibitor-induced enterocolitis. In this British Society of Gastroenterology endorsed guidance document, we have developed a consensus framework for the investigation and management of immune checkpoint inhibitor-induced enterocolitis.

Developing in vitro assays to transform gastrointestinal safety assessment: potential for microphysiological systems

Drug-induced gastrointestinal toxicities (DI-GITs) are among the most common adverse events in clinical trials. High prevalence of DI-GIT has persisted among new drugs due in part to the lack of robust experimental tools to allow early detection or to guide optimization of safer molecules. Developing in vitro assays for the leading GI toxicities (nausea, vomiting, diarrhoea, constipation, and abdominal pain) will likely involve recapitulating complex physiological properties that require contributions from diverse cell/tissue types including epithelial, immune, microbiome, nerve, and muscle. While this stipulation may be beyond traditional 2D monocultures of intestinal cell lines, emerging 3D GI microtissues capture interactions between diverse cell and tissue types. These interactions give rise to microphysiologies fundamental to gut biology. For GI microtissues, organoid technology was the breakthrough that introduced intestinal stem cells with the capability of differentiating into each of the epithelial cell types and that self-organize into a multi-cellular tissue proxy with villus- and crypt-like domains. Recently, GI microtissues generated using miniaturized devices with microfluidic flow and cyclic peristaltic strain were shown to induce Caco2 cells to spontaneously differentiate into each of the principle intestinal epithelial cell types. Second generation models comprised of epithelial organoids or microtissues co-cultured with non-epithelial cell types can successfully reproduce cross-'tissue' functional interactions broadening the potential of these models to accurately study drug-induced toxicities. A new paradigm in which in vitro assays become an early part of GI safety assessment could be realized if microphysiological systems (MPS) are developed in alignment with drug-discovery needs. Herein, approaches for assessing GI toxicity of pharmaceuticals are reviewed and gaps are compared with capabilities of emerging GI microtissues (e.g., organoids, organ-on-a-chip, transwell systems) in order to provide perspective on the assay features needed for MPS models to be adopted for DI-GIT assessment.

The role of immunosuppressive agents in the management of severe and refractory immune-related adverse events

The advent of immune checkpoint inhibitors has improved survival in some types of cancer and brought promising prospects to cancer immunotherapy. Despite their clinical benefits, significant off-target toxicities resulting from the immune system activation have been observed, namely immune-related adverse events (irAEs), which pose to clinicians a new challenge of optimal management. With steroids being the mainstay of current management of irAEs, immunosuppressive agents are especially indicated for severe or steroid-refractory cases, based on current immunopathophysiological knowledge and on extrapolations of treatment options for primary autoimmune disorders. This review focuses on the status and recent clinical progress of immunosuppressive agents in the management of severe and steroid-refractory irAEs.

Introduction

Cancer immunotherapy, especially immune checkpoint blockade therapy, represents a hotspot in cancer research. However, the low response rate, adaptive/acquired resistance, and adverse effects still keep most cancer patients from obtaining sustained clinical benefits. To overcome these limitations, it is essential to improve our understanding on the regulation of immune checkpoints under physiological and pathological contexts. Recent researches have gained insights into the molecular control of immune checkpoint receptors and ligands, which extended our knowledge on the immune system and provided alternative strategies for developing checkpoint inhibitors.