Cancer Immunotherapy with Anti-CTLA-4 Monoclonal Antibodies Induces an Inflammatory Bowel Disease

Dietary Considerations for Inflammatory Bowel Disease Are Useful for Treatment of Checkpoint Inhibitor-Induced Colitis

Checkpoint molecules are cell surface receptors on immune cells that mitigate excessive immune responses, but they have increased expression levels in cancer to facilitate immune escape. Checkpoint blockade therapies (e.g., anti-PD-1, anti-CTLA-4, and anti-LAG-3 therapy, among others) have been developed for multiple cancers. Colitis associated with checkpoint blockade therapy has pathophysiological similarities to inflammatory bowel disease (IBD), such as Crohn's disease and ulcerative colitis. Current therapeutic guidelines for checkpoint blockade-induced colitis include corticosteroids and, if the patient is refractory to steroids, immunomodulating antibodies, such as anti-TNF and anti-integrin agents. Interestingly, immunomodulatory molecules, such as TNFα, are upregulated in both IBD and checkpoint-mediated colitis. The inflammatory colitis toxicity symptoms from checkpoint blockade are similar to clinical symptoms experienced by patients with IBD. The pathophysiologic, dietary, and genetic factors associated with IBD will be reviewed. We will then explain how the principles developed for the treatment of IBD can be applied to patients experiencing inflammatory bowel toxicity secondary to checkpoint blockade.

Targeting cancer-related inflammation with non-steroidal anti-inflammatory drugs: Perspectives in pharmacogenomics

Inflammatory processes are essential for innate immunity and contribute to carcinogenesis in various malignancies, such as colorectal cancer, esophageal cancer and lung cancer. Pharmacotherapies targeting inflammation have the potential to reduce the risk of carcinogenesis and improve therapeutic efficacy of existing anti-cancer treatment. Non-steroidal anti-inflammatory drugs (NSAIDs), comprising a variety of structurally different chemicals that can inhibit cyclooxygenase (COX) enzymes and other COX-independent pathways, are originally used to treat inflammatory diseases, but their preventive and therapeutic potential for cancers have also attracted researchers' attention. Pharmacogenomic variability, including distinct genetic characteristics among different patients, can significantly affect pharmacokinetics and effectiveness of NSAIDs, which might determine the preventive or therapeutic success for cancer patients. Hence, a more comprehensive understanding in pharmacogenomic characteristics of NSAIDs and cancer-related inflammation would provide new insights into this appealing strategy. In this review, the up-to-date advances in clinical and experimental researches targeting cancer-related inflammation with NSAIDs are presented, and the potential of pharmacogenomics are discussed as well.

Immunotherapy for Cancer: Common Gastrointestinal, Liver, and Pancreatic Side Effects and Their Management

Cancer cells can block the activation of T lymphocytes by deploying inhibitory signals to cell surface receptors that downregulate the immune response. Immune checkpoint inhibitors (ICI) are monoclonal antibodies that regulate the immune response by acting on these receptors. The use of ICI has been successful for cancer types that do not respond well to conventional chemotherapy, showing clinical benefit in various advanced and metastatic cancers and supporting the promise of cancer immunotherapy. However, in some cases, these treatments are associated with immune-related adverse events, many of which affect the digestive system. The treatment of immune-related adverse events depends on the affected organ and the severity of symptoms. Here, we review the commonly used US FDA-approved ICI and briefly outline their mechanism of action. We also describe the resulting collateral effects on the gastrointestinal tract, liver, and pancreas and discuss their management and prognosis.

A case of refractory immune checkpoint inhibitor-induced colitis with Clostridioides difficile infection

The clinical symptoms of an immune checkpoint inhibitor (ICI)‐induced colitis are similar to those of ulcerative colitis. ICI‐induced colitis, like ulcerative colitis, may be complicated by other colitis, such as Clostridioides difficile infection (CDI). A 72‐year‐old man was admitted because of watery and bloody stools 10 times a day after three courses of nivolumab (antibodies against programmed death 1) and ipilimumab (cytotoxic T‐lymphocyte‐associated antigen‐4) for stage IV renal cell carcinoma. Colonoscopy revealed erythema and multiple erosions in the colon. Histopathological examination of colonic mucosa revealed diffuse inflammatory cell infiltration and apoptosis. The initial cytomegalovirus antigen test and C. difficile detection assay results were negative. Based on these findings, we diagnosed the patient with ICI‐induced colitis and discontinued ICI therapy. The symptoms did not improve despite the administration of Prednisolone and infliximab. A repeat colonoscopy revealed a new appearance of pseudomembranes from the sigmoid colon to the rectum one month after the start of these treatments. At this point, the patient tested positive for C. difficile. With treatment with vancomycin for CDI, the abdominal symptoms gradually decreased. Nivolumab alone was cautiously restarted. However, no colitis recurrence and further tumor reduction were observed. Here, we report our experience of a case of refractory ICI‐induced colitis complicated by CDI. ICI‐induced colitis may be complicated by CDI and should be carefully treated with repeated CDI testing if refractory to treatment. We believe that our observation will provide helpful information for determining an appropriate treatment strategy for ICI‐induced colitis.

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.

Immunotherapy-induced Colitis: A Comprehensive Review of Epidemiology, Clinical Presentation, Diagnostic Workup, and Management Plan

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of a variety of malignancies including advanced melanoma, non-small cell lung cancer, renal cell carcinoma, head and neck cancers among others. Since their introduction, there has been significant improvement in survival and prognosis in patients with advanced malignancies. Unfortunately, improved outcomes have come at a price of significant immune-related adverse events, with those of the gastrointestinal tract being the most common. Gastrointestinal immune-related adverse events frequently present as diarrhea and colitis, the severity of which can range from mild diarrhea to fulminant colitis with intestinal perforation. Currently, management of ICI-induced colitis is primarily guided by retrospective studies and expert opinion. A significant number of ICI-induced colitis responds to high-dose corticosteroids; however, some patients require further therapy with biologics. There is limited information on the factors which may predispose patients to ICI-induced colitis. Future research elucidating these risk factors along with development of a scoring system could allow for risk-stratification of patients before initiation of ICI therapy. Such a system may help clinicians and patients keep a high index of suspicion regarding ICI-induced colitis and could hopefully reduce the incidence of severe cases. Similarly, future studies should investigate protective factors against ICI-induced colitis, which could potentially allow more patients to safely benefit from ICI therapy.

Late-onset toxicities of monoclonal antibodies in cancer patients

Cancer therapy duration is variable and may take years, adding a new challenge of maintaining the best life quality for cancer survivors. In cancer patients, late-onset toxicities have been reported with monoclonal antibodies and may involve several body organs or systems. They are defined as an autoimmune illnesses that can happen months to years after treatment discontinuation. Late-onset toxicities have become a focus of clinical care and related research. After cancer therapy is completed, the patient should receive longitudinal follow-up to detect these late effects as early as possible. The current review summarizes the recently reported late-onset toxicities of four classes of monoclonal antibodies (anti-CD52, anti-CTLA-4, anti-PD-1 and anti-CD20) with guidance for the diagnostic tools, appropriate management and treatment.

Risk factors and predictors of immune-related adverse events: implications for patients with non-small cell lung cancer

INTRODUCTION

Immune checkpoint inhibitors (ICI) are now utilized as a standard of care treatment for multiple cancers, including in both the metastatic setting as well as in earlier stages of disease. The identification of unique immune-related adverse events (irAE) that occur during ICI treatment has led to intense research to identify potential risk factors and biomarkers that may assist in clinical decision making. Although initial studies in ICI were primarily in advanced stage disease, the use of ICI in earlier stages of disease as adjuvant therapies requires a better understanding of patient risk stratification to mitigate or prevent serious irAE.

AREAS COVERED

In this review, we set out to describe the current state of research regarding potential risk factors for irAE in patients with non-small cell lung cancer, as well as explore the barriers to understanding irAE. We review data from irAE that occur in large phase 3 trials and prospective studies focusing on irAE, as well as the many retrospective studies that currently form the bulk of our understanding of irAE.

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

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

Leveraging structural and 2D-QSAR to investigate the role of functional group substitutions, conserved surface residues and desolvation in triggering the small molecule-induced dimerization of hPD-L1

Small molecules are rising as a new generation of immune checkpoints’ inhibitors, with compounds targeting the human Programmed death-ligand 1 (hPD-L1) protein are pioneering this area of research. Promising examples include the recently disclosed compounds from Bristol-Myers-Squibb (BMS). These molecules bind specifically to hPD-L1 through a unique mode of action. They induce dimerization between two hPD-L1 monomers through the hPD-1 binding interface in each monomer, thereby inhibiting the PD-1/PD-L1 axis. While the recently reported crystal structures of such small molecules bound to hPD-L1 reveal valuable insights regarding their molecular interactions, there is still limited information about the dynamics driving this unusual complex formation. The current study provides an in-depth computational structural analysis to study the interactions of five small molecule compounds in complex with hPD-L1. By employing a combination of molecular dynamic simulations, binding energy calculations and computational solvent mapping techniques, our analyses quantified the dynamic roles of different hydrophilic and lipophilic residues at the surface of hPD-L1 in mediating these interactions. Furthermore, ligand-based analyses, including Free-Wilson 2D-QSAR was conducted to quantify the impact of R-group substitutions at different sites of the phenoxy-methyl biphenyl core. Our results emphasize the importance of a terminal phenyl ring that must be present in any hPD-L1 small molecule inhibitor. This phenyl moiety overlaps with a very unfavorable hydration site, which can explain the ability of such small molecules to trigger hPD-L1 dimerization.

Predictive Biomarkers of Severe Immune-Related Adverse Events With Immune Checkpoint Inhibitors: Prevention, Underlying Causes, Intensity, and Consequences

Immune checkpoint inhibitors (ICIs) have dramatically transformed oncology by prolonging overall survival and yielding better patient tolerance compared to other chemotherapeutic agents. However, numerous questions remain unanswered about the toxicity profile of ICIs, its relationship with the treatment response, and causes underlying the excellent treatment response in some patients, while recalcitrance in others. Research groups have continued to seek biomarkers that may permit the identification of treatment responders and predict toxicity to facilitate cessation of immunotherapy before the development of severe toxicity. However, some studies have found associations between serious adverse events and longer survivorship. The research question entailed determining whether a biomarker is needed to predict severe immune-related adverse events prior to their development or whether providing early treatment for toxicity would inhibit the immune system from attaining a long-lasting anti-tumor effect. Therefore, this review conducted an in-depth analysis into the molecular basis of these observations.

Emerging Management Approach for the Adverse Events of Immunotherapy of Cancer

Immunotherapy, which stimulates the body’s immune system, has received a considerable amount of press in recent years because of its powerful benefits. Cancer immunotherapy has shown long-term results in patients with advanced disease that are not seen with traditional chemotherapy. Immune checkpoint inhibitors, cytokines like interleukin 2 (IL-2) and interferon-alpha (IFN), and the cancer vaccine sipuleucel-T have all been licensed and approved by the FDA for the treatment of various cancers. These immunotherapy treatments boost anticancer responses by stimulating the immune system. As a result, they have the potential to cause serious, even fatal, inflammatory and immune-related side effects in one or more organs. Immune checkpoint inhibitors (ICPIs) and chimeric antigen receptor (CAR) T-cell therapy are two immunotherapy treatments that are increasingly being used to treat cancer. Following their widespread usage in the clinic, a wave of immune-related adverse events (irAEs) impacting virtually every system has raised concerns about their unpredictability and randomness. Despite the fact that the majority of adverse effects are minimal and should be addressed with prudence, the risk of life-threatening complications exists. Although most adverse events are small and should be treated with caution, the risk of life-threatening toxicities should not be underestimated, especially given the subtle and unusual indications that make early detection even more difficult. Treatment for these issues is difficult and necessitates a multidisciplinary approach involving not only oncologists but also other internal medicine doctors to guarantee quick diagnosis and treatment. This study’s purpose is to give a fundamental overview of immunotherapy and cancer-related side effect management strategies.

Noninvasive Prediction of Outcomes in Autoimmune Hepatitis-Related Cirrhosis

The value of noninvasive tools in the diagnosis of autoimmune hepatitis (AIH)-related cirrhosis and the prediction of clinical outcomes is largely unknown. We sought to evaluate (1) the utility of liver stiffness measurement (LSM) in the diagnosis of cirrhosis and (2) the performance of the Sixth Baveno Consensus on Portal Hypertension (Baveno VI), expanded Baveno VI, and the ANTICIPATE models in predicting the absence of varices needing treatment (VNT). A multicenter cohort of 132 patients with AIH-related cirrhosis was retrospectively analyzed. LSM and endoscopies performed at the time of cirrhosis diagnosis were recorded. Most of the patients were female (66%), with a median age of 54 years. Only 33%-49% of patients had a LSM above the cutoff points described for the diagnosis of AIH-related cirrhosis (12.5, 14, and 16 kPa). Patients with portal hypertension (PHT) had significantly higher LSM than those without PHT (15.7 vs. 11.7 kPa; P = 0.001), but 39%-52% of patients with PHT still had LSM below these limits. The time since AIH diagnosis negatively correlated with LSM, with longer time being significantly associated with a lower proportion of patients with LSM above these cutoffs. VNT was present in 12 endoscopies. The use of the Baveno VI, expanded Baveno VI criteria, and the ANTICIPATE model would have saved 46%-63% of endoscopies, but the latter underpredicted the risk of VNT. Conclusions: LSM cutoff points do not have a good discriminative capacity for the diagnosis of AIH-related cirrhosis, especially long-term after treatment initiation. Noninvasive tools are helpful to triage patients for endoscopy.

Chronic Use of Proton Pump Inhibitors Is Associated With an Increased Risk of Immune Checkpoint Inhibitor Colitis in Renal Cell Carcinoma

INTRODUCTION

Immune checkpoint inhibitors (ICIs) have become a standard of care in metastatic renal cell carcinoma (mRCC) but are associated with immune-related adverse events (irAEs) including colitis. Growing evidence suggests proton pump inhibitors (PPIs) increase the risk of inflammatory bowel disease (IBD). Given the pathophysiological overlap between IBD and ICI colitis, we sought to evaluate the relationship between PPI use and ICI colitis in mRCC patients.

PATIENTS AND METHODS

We performed a retrospective study of adult patients who received ICI therapy for mRCC between 2015 and 2018 at University of Texas Southwestern Medical Center affiliated hospitals. Clinical characteristics, oncological outcomes, ICI colitis details, and PPI use details were collected by manual chart review. The diagnosis of ICI colitis was made via biopsy when available, or by clinical criteria (symptoms and response to immunosuppressive therapy) when biopsy specimens were unavailable or inconclusive. Univariable and multivariable logistic regression analyses were conducted to assess the potential contribution of PPIs to ICI colitis.

RESULTS

A total of 176 patients received ICI therapy for mRCC, of which 16 (9.1%) were diagnosed with ICI colitis. Patients with ICI colitis presented with elevated stool lactoferritin and calprotectin and a wide range of endoscopic and histologic findings. There were no significant differences between patients with and without ICI colitis in age, gender, medical comorbidities, RCC history, and overall survival. However, exposure to ipilimumab and PPI use were more frequently observed in patients with ICI colitis than those without. In univariable and multivariable logistic regression analyses, exposure to ipilimumab and chronic use of PPIs > 8 weeks were significantly associated with ICI colitis.

CONCLUSION

In addition to ipilimumab use, chronic use of PPIs may be associated with ICI colitis in patients with mRCC.

Gut inflammation induced by drugs: Can pathology help to differentiate from inflammatory bowel disease?

Drug‐induced mucosal injury (DIMI) in the gastrointestinal tract is important to recognise, partly because cessation of the culprit agent alone may result in resolution of symptoms. An ever‐growing list of medications, including newer immunotherapeutic agents and targeted therapies, can cause gastrointestinal inflammation of varying severity. However, the diagnosis of DIMI is challenging, as a single drug can induce a variety of histopathological patterns of injury including acute colitis, chronic colitis, microscopic colitis, apoptotic colopathy, and ischaemic‐type colitis. An additional consideration is the potential clinical, endoscopic and histological overlap of DIMI with gastrointestinal mucosal injury secondary to other entities such as inflammatory bowel disease (IBD). We discuss DIMI of the gastrointestinal tract with an emphasis on histological patterns that mimic IBD, histological features which may distinguish the two entities, and the diagnostic role and limitations of the pathologist.

Role of Abdominal and Pelvic CT Scans in Diagnosis of Patients with Immunotherapy-Induced Colitis

Introduction:

Colitis is one of the most common immune-related adverse events in patients receiving immune checkpoint inhibitors. Although radiographic changes on computed tomography (CT), such as mild diffuse bowel thickening, mesenteric fat stranding, and mucosal enhancement, have been reported, the utility of CT in diagnosis of patients with suspected immune-related colitis is not well documented. The aim of this retrospective study was to determine the value of CT scans in diagnosis of immunotherapy-induced colitis.

Methods:

CT scans of the abdomen and pelvis of 34 patients receiving immunotherapy who had a clinical diagnosis of immunotherapy-induced colitis and 19 patients receiving immunotherapy without clinical symptoms of colitis (controls) were evaluated. Segments of the colon (rectum, sigmoid, descending, transverse, ascending, and cecum) were assessed independently by two abdominal imaging specialists, blinded to the clinical diagnosis. Each segment was assessed for radiographic signs such as mucosal enhancement, wall thickening, distension, and periserosal fat stranding. The presence of any of the signs was considered radiographic evidence of colitis.

Results:

CT findings suggestive of colitis was seen in 20 of 34 patients with symptoms of colitis and in 5 of 19 patients without symptoms of colitis. The sensitivity, specificity, positive predictive value, and negative predictive value for colitis on CT were 58.8%, 73.7%, 80%, and 50%, respectively.

Conclusions:

We found that CT had a low sensitivity, specificity, and negative predictive value for the diagnosis of immunotherapy-induced colitis. We therefore conclude that CT has a limited role in the diagnosis of patients with suspected uncomplicated immune-related colitis.

Intestinal Haemorrhage and Colitis Induced by Treatment With Osimertinib for Non-Small-Cell Lung Carcinoma: A Case Report

Background: Osimertinib is recommended either as the first-line therapy for sensitizing EGFR-mutations (FLAURA trial) or at progression to first-/second-generation EGFR inhibitors in the presence of resistance mutation T790M (AURA 3 study). It can effectively improve the prognosis of patients with NSCLC with manageable adverse reactions. Among adverse events, intestinal haemorrhage is rare and requires extensive study on its potential lethality.

Case presentation: A 59-year-old female, diagnosed with relapsed stage IV (cT4N2M1c) NSCLC with T790M mutation of the EGFR gene, received osimertinib treatment. Eight months after osimertinib treatment, she complained of lower abdominal pain and haematochezia without haemorrhoids. Potential causes of intestinal haemorrhage other than osimertinib toxicity were ruled out. Colonoscopy examination showed severe colitis with grade 3 CTCAE. Osimertinib was discontinued, and prednisone 0.5 mg/kg was administered. Follow-up endoscopy showed no pathological findings. A novel third-generation EGFR-TKI, aumolertinib, was administrated. Five months after aumolertinib initiation, CT evaluation showed stable disease (SD), and this patient was free of colitis recurrence.

Conclusion: To our knowledge, this is the first case report of severe colitis as an adverse event associated with osimertinib. Although osimertinib is the standard treatment for NSCLC in patients with T790M mutation and has fewer side effects, colitis may occur after months of treatment. Aumolertinib, a novel third-generation EGFR-TKI, might be an effective alternative for the treatment of patients with NSCLC experiencing colitis from osimertinib.

The cure from within? a review of the microbiome and diet in melanoma

Therapy for cutaneous melanoma, the deadliest of the skin cancers, is inextricably linked to the immune system. Once thought impossible, cures for metastatic melanoma with immune checkpoint inhibitors have been developed within the last decade and now occur regularly in the clinic. Unfortunately, half of tumors do not respond to checkpoint inhibitors and efforts to further exploit the immune system are needed. Tantalizing associations with immune health and gut microbiome composition suggest we can improve the success rate of immunotherapy. The gut contains over half of the immune cells in our bodies and increasingly, evidence is linking the immune system within our gut to melanoma development and treatment. In this review, we discuss the importance the skin and gut microbiome may play in the development of melanoma. We examine the differences in the microbial populations which inhabit the gut of those who develop melanoma and subsequently respond to immunotherapeutics. We discuss the role of dietary intake on the development and treatment of melanoma. And finally, we review the landscape of published and registered clinical trials therapeutically targeting the microbiome in melanoma through dietary supplements, fecal microbiota transplant, and microbial supplementation.

Holistic Approach to Immune Checkpoint Inhibitor-Related Adverse Events

Immune checkpoint inhibitors (ICIs) block inhibitory molecules, such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), or its ligand, programmed cell death protein ligand 1 (PD-L1) and enhance antitumor T-cell activity. ICIs provide clinical benefits in a percentage of patients with advanced cancers, but they are usually associated with a remarkable spectrum of immune-related adverse events (irAEs) (e.g., rash, colitis, hepatitis, pneumonitis, endocrine, cardiac and musculoskeletal dysfunctions). Particularly patients on combination therapy (e.g., anti-CTLA-4 plus anti-PD-1/PD-L1) experience some form of irAEs. Different mechanisms have been postulated to explain these adverse events. Host factors such as genotype, gut microbiome and pre-existing autoimmune disorders may affect the risk of adverse events. Fatal ICI-related irAEs are due to myocarditis, colitis or pneumonitis. irAEs usually occur within the first months after ICI initiation but can develop as early as after the first dose to years after ICI initiation. Most irAEs resolve pharmacologically, but some appear to be persistent. Glucocorticoids represent the mainstay of management of irAEs, but other immunosuppressive drugs can be used to mitigate refractory irAEs. In the absence of specific trials, several guidelines, based on data from retrospective studies and expert consensus, have been published to guide the management of ICI-related irAEs.

Immune-Related Adverse Events (irAEs) in Cancer, with Inputs from a Nursing Expert: A Review

Immune checkpoint inhibitors (ICPis) belong to a group of immunotherapeutic agents that act on different immune cells and tumor cells and reactivate the suppressed immune system of the host. The emergence of immunotherapy has resulted in the successful management of many malignancies. High success rates with certain advanced cancers have attributed wide importance and relevance to the use of immunotherapy. Although ICPis have gained huge popularity, their use often leads to side effects that can affect almost any system; immune-related adverse events (irAEs). These adverse events occur due to unrestrained T cell activity that unsettles the immune homeostasis of the host. Although close monitoring for toxicities controls the events on most of the occasions, the inability to diagnose them early may prove fatal on some occasions due to their subtle and nonspecific symptoms. This review summarizes in brief the usual irAEs and their management, besides a very important nursing perspective, from a nursing expert about an overall insight into the routine irAEs.

Pharmacological Interventions for the Prevention and Treatment of Immune Checkpoint Inhibitor-Associated Enterocolitis: A Systematic Review

BACKGROUND

Patients treated with immune checkpoint inhibitors (ICIs) may develop ICI-associated enterocolitis, for which there is no approved treatment.

AIMS

We aimed to systematically review the efficacy and safety of medical interventions for the prevention and treatment of ICI-associated enterocolitis.

METHODS

MEDLINE, EMBASE, and the Cochrane Library were searched to identify randomized controlled trials (RCTs), cohort and case-control studies, and case series/reports, evaluating interventions (including corticosteroids, biologics, aminosalicylates, immunosuppressants, and fecal transplantation) for ICI-associated enterocolitis. Clinical, endoscopic, and histologic efficacy endpoints were evaluated. The Grading of Recommendations, Assessment, Development, and Evaluation criteria were used to assess overall quality of evidence.

RESULTS

A total of 160 studies (n = 1514) were included (one RCT, 3 retrospective cohort studies, 156 case reports/case series). Very low quality evidence from one RCT suggests budesonide is not effective for prevention of ICI-associated enterocolitis in ipilimumab-treated patients (relative risk 0.93 [95% confidence interval 0.56, 1.56]). Very low quality evidence suggests that corticosteroids, infliximab, and vedolizumab may be effective for treatment of ICI-associated enterocolitis by inducing clinical response and remission. No validated indices for measuring disease activity were used. Biologic treatment was used in 42% (641/1528) of patients, as reported in 97 studies. ICIs were discontinued in 65% (457/702) of patients, as reported in 63 studies.

CONCLUSIONS

Current treatment recommendations for ICI-associated enterocolitis are based on very low quality evidence, primarily from case reports and case series. Large-scale prospective cohort studies and RCTs are needed to develop prophylactic and therapeutic treatments to minimize interruption or discontinuation of oncological therapies.

Endoscopic and histopathologic features of Anti‐PD‐1‐related collagenous colitis

Objectives

Cancer patients treated with immune checkpoint inhibitors occasionally show persistent diarrhea accompanied by endoscopic features of ulcerative colitis. The endoscopic mucosal inflammation may appear mild in some patients compared to the clinical severity, which can make choosing a treatment challenging. In this study, we evaluated the factors that support the continuation of chemotherapy by assessing the endoscopic and histopathological characteristics of patients who experienced diarrhea after immune checkpoint inhibitor administration.

Methods

This study included eight patients who were diagnosed with collagenous colitis based on pathological assessments. We retrospectively investigated these patients’ backgrounds, laboratory data, and computed tomography images that were extracted from their medical records. We also summarized their endoscopic and pathologic findings.

Results

All eight patients were being treated with anti‐programmed cell death‐1/programmed cell death‐ligand 1 therapeutic agents and had a recent history of oral proton pump inhibitor therapy. The anti‐programmed cell death‐1‐related collagenous colitis in these cases was characterized by endoscopically mild mucosal inflammation, high fecal calprotectin levels, and a lower frequency of intestinal wall thickening on computed tomography. Histological assessments showed CD8⁺ lymphocytes predominantly infiltrating the lamina propria and crypts of the colonic mucosa. Suspending the proton pump inhibitor therapy relieved the patients’ symptoms and allowed the continuation of the anti‐programmed cell death‐1/programmed cell death‐ligand 1 therapy.

Conclusions

Anti‐programmed cell death‐1‐related collagenous colitis is reversible; appropriate diagnosis of adverse events is crucial for the continuation of immune checkpoint inhibitor therapy.

Radiation‑induced enterocolitis after combination therapy with palliative radiotherapy and immune checkpoint inhibitors in patients with metastatic lung cancer

The impact of immune checkpoint inhibitors (ICIs) on radiation-induced enterocolitis (RIE) after palliative radiotherapy (PRT) to the bowel has remained to be fully investigated. The aim of the present study was to investigate whether ICIs affect RIE after PRT. For this purpose, 32 lesions (vertebral bone, 13; pelvic bone, 12; adrenal gland, 3; lymph node, 3; liver, 1) in 28 patients with metastatic lung cancer who were treated with both PRT involving the bowel (8-48 Gy; typically 30 Gy in 10 fractions or 20 Gy in 5 fractions) and ICIs between December 2015 and June 2021 were retrospectively reviewed. A total of 12 lesions were treated with ICIs only prior to PRT, 16 received ICIs only after PRT and the remaining 4 received ICIs both prior to and after PRT. The 1-year overall survival rate was 53%. The median PRT dose was 30 Gy (range, 8-48 Gy) in 10 fractions (range, 1-24 fractions). The median interval between PRT and the closest administration of ICIs was 20.5 days (range, 1-212 days). Combination therapy with PRT and ICIs was well tolerated by the majority of patients. However, grade 2 or higher RIE occurred in 6.3% of the patients. In these patients, ICIs were administered within 7 days after completing PRT with 3.6 Gy or a higher-fraction dose (evaluated at the isocenter). There were significant differences in the incidence of RIE between administration of ICIs <7 days after PRT completion and ≥7 days (P=0.05), between <3.6 Gy per fraction and ≥3.6 Gy (P=0.04), and between maximum dose to 2 cc (D2cc) of large bowel <3.3 Gy and D2cc of large bowel ≥3.3 Gy (P=0.02). There was no clear association between the incidence of RIE and any other factors. These results suggest that the administration of ICIs soon after PRT completion and a comparatively high fraction dose may potentially increase the risk of grade 2 or higher RIE.

Recommendations for standardizing biopsy acquisition and histological assessment of immune checkpoint inhibitor-associated colitis

Immune checkpoint inhibitor-associated colitis (ICIC) affects approximately 15% of cancer patients treated with immunotherapy. Although histological evaluation is potentially valuable for both the diagnosis of ICIC and evaluation of disease activity, use in clinical practice is heterogeneous. We aimed to develop expert recommendations to standardize histological assessment of disease activity in patients with ICIC. Using the modified Research and Development/University of California Los Angeles (RAND/UCLA) appropriateness methodology, an international panel of 11 pathologists rated the appropriateness of 99 statements on a 9-point Likert scale during two rounds of anonymous voting. Results were discussed between rounds using moderated videoconferences. There are currently no disease-specific instruments for assessing histological features of ICIC. The panel considered that colonoscopy with at least three biopsies per segment from a total of at least five segments, including both endoscopically normal and inflamed areas, was appropriate for tissue acquisition. They agreed that biopsies should be oriented such that the long axis of the colonic crypts is visualized and should be stained with hematoxylin and eosin. Histological items that the panel voted were appropriate to evaluate in ICIC included the degree of structural/architectural change, chronic inflammatory infiltrate, lamina propria and intraepithelial neutrophils, crypt abscesses and destruction, erosions/ulcerations, apoptosis, surface intraepithelial lymphocytosis, and subepithelial collagen thickness. The appropriateness of routine immunohistochemistry was uncertain. These expert recommendations will help standardize assessment of histological activity in patients with ICIC. The panel also identified the development and validation of an ICIC-specific histological index as a research priority.

Clinical Course and Impact of Immune Checkpoint Inhibitor Colitis Resembling Microscopic Colitis

Background

Microscopic colitis (MC) is suspected to result from increased immune activity in gut mucosa. Immune checkpoint inhibitors (ICIs) treat cancer by activating the immune system, and further investigation is needed regarding their role in the development of MC.

Methods

A retrospective case series investigated cases of endoscopically and histologically confirmed MC developing after administration of ICIs. Clinical notes and medication administration records were reviewed for demographics, symptom duration, and treatment response.

Results

Nineteen cases of de novo MC were identified, with 95% of cases requiring steroid treatment, 53% presenting with hospitalization, and colitis-related mortality in 1 individual. Symptom onset occurred a median of 160 days after initiation of ICI therapy and 53 days after their most recent dose of therapy. Patients had a median of 125 days of symptoms, and ICI therapy was held in 70% of individuals due for treatment.

Conclusions

MC can develop after ICI administration, and presents with severe symptoms, often requiring hospitalization and steroid treatment. In certain individuals this can require a prolonged treatment course of steroid therapy or immunomodulators. Individuals developing diarrhea after ICI therapy warrant thorough workup including endoscopy and rapid treatment initiation given the disease severity observed in this series.

ECCO Topical Review on Clinicopathological Spectrum and Differential Diagnosis of Inflammatory Bowel Disease

INTRODUCTION

Many diseases can imitate inflammatory bowel disease [IBD] clinically and pathologically. This review outlines the differential diagnosis of IBD and discusses morphological pointers and ancillary techniques that assist with the distinction between IBD and its mimics.

METHODS

European Crohn's and Colitis Organisation [ECCO] Topical Reviews are the result of an expert consensus. For this review, ECCO announced an open call to its members and formed three working groups [WGs] to study clinical aspects, pathological considerations, and the value of ancillary techniques. All WGs performed a systematic literature search.

RESULTS

Each WG produced a draft text and drew up provisional Current Practice Position [CPP] statements that highlighted the most important conclusions. Discussions and a preliminary voting round took place, with subsequent revision of CPP statements and text and a further meeting to agree on final statements.

CONCLUSIONS

Clinicians and pathologists encounter a wide variety of mimics of IBD, including infection, drug-induced disease, vascular disorders, diverticular disease, diversion proctocolitis, radiation damage, and immune disorders. Reliable distinction requires a multidisciplinary approach.

Vedolizumab Attenuates Immune-Checkpoint-Therapy-Induced Infliximab-Refractory Colitis

Immune checkpoint inhibitors (ICIs), such as nivolumab and ipilimumab, have drastically changed treatments of advanced melanoma. However, ICI-related enterocolitis is often the most common adverse event, and represents the main reason for ICI discontinuation and mortalities. Here, we report the case of a metastatic melanoma treated with vedolizumab for ICI-induced colitis. A 67-year-old man treated with ipilimumab and nivolumab developed ICI-induced colitis and grade 3 diarrhea refractory to methylprednisolone and infliximab. After his third dose of vedolizumab, oral prednisolone ceased, and the colitis had completely resolved with no recurrence. This case report supports vedolizumab use in treating severe colitis which failed to resolve with first- and second-line immunosuppressive therapy.

Checkpoint Inhibitors and the Gut

Checkpoint inhibitors have revolutionized treatments in modern oncology, including many conditions previously relegated to palliative therapies only. However, emerging recognition of checkpoint inhibitor-related adverse events has complicated the status of checkpoint inhibitor-related therapies. This review article discusses gastrointestinal adverse events as a result of checkpoint inhibitor therapy, as well as limitations of current guidelines, thus providing recommendations for guideline revision and future study direction.

Histological Features of Celiac-Disease-like Conditions Related to Immune Checkpoint Inhibitors Therapy: A Signal to Keep in Mind for Pathologists

Immune checkpoint inhibitors (ICIs) targeting cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), programmed cell death protein (PD-1), and its ligand PDL-1, are finding increasing application in the treatment of malignant neoplasms. The widespread clinical use of these drugs, however, resulted in the discovery of side effects. The occurrence of celiac disease (CD) after ICIs therapy has been reported in the literature, but its incidence remains unknown and the role of ICIs in its onset is not yet clear. In this review, we examine the published data on this topic in order to better understand and define this entity from a histological point of view. We performed an electronic literature search to identify original reports in which CD or pathological CD-like conditions were documented histologically in patients treated with ICIs. We identified ten papers. A total of twenty-five patients were included in these publications, eleven of them receiving a serologic and histological diagnosis of CD, and four a histological diagnosis of CD-like conditions, in which pathogenesis appears to be multifactorial. ICIs can cause a CD-like enteropathy and biopsies with clinical integration are crucial to diagnose this condition. CD rarely has been observed during treatment with ICIs and its morphological aspects are similar to ICIs-CD enteropathy. Moreover, the onset of ICIs-CD may have a distinct immune mechanism compared to classical CD. Thus, the pathologists must make a histological diagnosis of CD with caution and only in adequate clinical and serological context.

A Review of Potential Role of Capsule Endoscopy in the Work-Up for Chemotherapy-Induced Diarrhea

Chemotherapy-induced diarrhea (CID) is a common, severe side effect of chemotherapy, immunotherapy, and targeted therapy. Because patients are more prone to continuing chemotherapy if they do not suffer from CID, appropriate diagnosis and monitoring of this disease are essential. However, suitable monitoring methods are yet to be developed. To date, several studies have shown that small-bowel capsule endoscopy (SBCE) is useful in visualizing the entire small intestinal mucosa and detecting small intestinal abnormalities, including bleeding, malignant tumors, and mucosal injury, associated with the use of nonsteroidal anti-inflammatory drugs and low-dose aspirin. Currently, limited studies have evaluated the small intestinal mucosa using SBCE in patients receiving fluoropyrimidine-based chemotherapy or immune checkpoint inhibitors. These studies have reported that small intestinal mucosal injury is common in patients with severe fluoropyrimidine-induced diarrhea. SBCE might be a useful screening method for the early detection of enterocolitis induced by immune checkpoint inhibitors. SBCE may be a powerful tool for the diagnosis and monitoring of CID, and understanding its indication, contraindication, and capsule-retention risk for each patient is important for clinicians.

Immunotherapy-Mediated Luminal Gastrointestinal Toxicities

The advent of immune checkpoint blockade and its application in the management of advanced malignancies has revolutionized cancer therapies, outcomes, and survival. As beneficial as these class of drugs have been proven to be, their use is not devoid of complications, viz., immune-related adverse events (irAEs). The gastrointestinal (GI) tract is the second most frequently affected organ system, and toxicities may vary in severity from mild disease to aggressive life-threatening clinical presentations. Timely diagnosis that incorporates clinical, biochemical, imaging, endoscopic, and histologic evaluation is imperative for efficacious management of this disease process to ensure good outcomes. Management varies depending on severity and can comprise supportive care in milder disease patterns as well as vigorous immunosuppression in aggressive cases.

Update on Immune Checkpoint Inhibitor Enterocolitis

PURPOSE OF REVIEW

Immune checkpoint inhibitor (ICI) therapy revolutionized the treatment of multiple solid and hematologic malignancies. Yet, with it came profound inflammatory toxicities that mimic autoimmune diseases, termed immune-related adverse events (irAEs). Prominent among these is gastrointestinal inflammation, including a spectrum of gastritis, enteritis, and colitis. Here we synthesize an approach to immune checkpoint related enterocolitis (irEC) - including diagnostics and therapeutics - underpinned by new insights into the mechanism behind these phenomena.

RECENT FINDINGS

This review presents updated insights on how to approach irEC, including novel approaches to selective immunosuppressive therapy, the role of fecal microbiota transplant, and the underlying cellular mechanisms of irEC. This review provides an update on irEC diagnosis and therapy, with considerations of new therapies and special patient populations. The field of gastrointestinal irAEs requires additional investigation, which will ultimately provide the tools required for patients to continue to receive life-saving ICI therapy.

Differential diagnosis and management of immune checkpoint inhibitor-induced colitis: A comprehensive review

Immune checkpoint inhibitors (ICIs) are a new class of cancer pharmacotherapy consisting of antibodies that block inhibitory immune regulators such as cytotoxic T lymphocyte antigen 4, programmed cell death 1 and programmed death-ligand 1. Checkpoint blockade by ICIs reactivates a tumor-specific T cell response. Immune-related adverse events can occur in various organs including skin, liver, and gastrointestinal tract. Mild to severe colitis is the most common side effect with some experiencing rapid progression to more serious complications including bowel perforation and even death. Prompt diagnosis and management of ICI-induced colitis is crucial for optimal outcome. Unfortunately, its clinical, endoscopic and histopathologic presentations are non-specific and overlap with those of colitis caused by other etiologies, such as infection, medication, graft-versus-host disease and inflammatory bowel disease. Thus, a definitive diagnosis can only be rendered after these other possible etiologies are excluded. Sometimes an extensive clinical, laboratory and radiologic workup is required, making it challenging to arrive at a prompt diagnosis. Most patients experience full resolution of symptoms with corticosteroids and/or infliximab. For ICI-induced colitis that is treatment-refractory, small scale studies offer alternative strategies, such as vedolizumab and fecal microbiota transplantation. In this review, we focus on the clinical features, differential diagnosis, and management of ICI-induced colitis with special attention to emerging treatment options for treatment-refractory ICI-induced colitis.

Therapeutic agents affecting the immune system and drug-induced inflammatory bowel disease (IBD): A review on etiological and pathogenetic aspects

In recent years, therapeutic agents affecting the immune system have been largely implemented in the treatment of various hematological, rheumatological and dermatological disorders. Their clinical use has offered important benefits for affected patients and has also ameliorated clinical outcome and prognosis in many cases. Nonetheless, as any treatment, the use of these drugs may be associated with side effects. One of the target organs in such cases is the gastrointestinal tract. In particular, the exacerbation or the onset of inflammatory bowel disease (IBD) in treated patients is not infrequent, although the mechanism of action of these agents may be different. In this review we will focus on the use of therapeutic agents affecting the immune system and the development or exacerbation of IBD, with a mention on the possible underlying pathogenetic mechanisms.

Immune Checkpoint Inhibitor-Associated Colitis: From Mechanism to Management

Immune checkpoint inhibitors (ICIs), as one of the innovative types of immunotherapies, including programmed cell death-1 (PD-1), programmed cell death-ligand 1 (PD-L1), and cytotoxic T lymphocyte antigen 4 (CTLA-4) inhibitors, have obtained unprecedented benefit in multiple malignancies. However, the immune response activation in the body organs could arise immune-related adverse events (irAEs). Checkpoint inhibitor colitis (CIC) is the most widely reported irAEs. However, some obscure problems, such as the mechanism concerning gut microbiota, the confusing differential diagnosis with inflammatory bowel disease (IBD), the optimal steroid schedule, the reintroduction of ICIs, and the controversial prognosis features, influence the deep understanding and precise diagnosis and management of CIC. Herein, we based on these problems and comprehensively summarized the relevant studies of CIC in patients with NSCLC, further discussing the future research direction of this specific pattern of irAEs.

Gastrointestinal Adverse Events Induced by Immune-Checkpoint Inhibitors

BACKGROUND

As immune-checkpoint inhibitors (ICI) are becoming standard therapies for malignant tumors, increasing attention has been paid to their associated immune-related adverse events (irAEs). The gastrointestinal tract is the major site of irAEs, and it has recently become evident that the large bowel is the most frequently affected region. The aim of this narrative review was to clarify the endoscopic and histopathologic findings of and treatments for ICI-induced colitis.

SUMMARY

Endoscopic findings of ICI-induced colitis include a reddish, edematous mucosa with increased mucous exudate, loss of normal vascularity, and a granular mucosa with or without mucosal breaks. Histopathologic findings of ICI-induced colitis are expansion of the lamina propria, intraepithelial infiltration of neutrophils, crypt architectural distortion, neutrophilic crypt abscess, and prominent apoptosis. The clinical, endoscopic, and histopathologic severity of ICI-induced colitis is diverse, but colonoscopy together with biopsy is necessary for diagnosis. While a certain proportion of patients with ICI-induced colitis have an intractable clinical course, management guidelines are based on retrospective analyses. Prospective studies are needed to assess the efficacy of various medications, including immunosuppressive regimens. Key Messages: Colonoscopy with biopsy is the gold standard for the diagnosis of ICI-induced colitis. Endoscopists should be aware of the clinical features and pathophysiology of ICI-induced colitis for prompt diagnosis and treatment planning.

Management of Immune-Related Adverse Events in Patients Treated With Immune Checkpoint Inhibitor Therapy: ASCO Guideline Update

PURPOSE

To increase awareness, outline strategies, and offer guidance on the recommended management of immune-related adverse events (irAEs) in patients treated with immune checkpoint inhibitor (ICPi) therapy.

METHODS

A multidisciplinary panel of medical oncology, dermatology, gastroenterology, rheumatology, pulmonology, endocrinology, neurology, hematology, emergency medicine, nursing, trialists, and advocacy experts was convened to update the guideline. Guideline development involved a systematic literature review and an informal consensus process. The systematic review focused on evidence published from 2017 through 2021.

RESULTS

A total of 175 studies met the eligibility criteria of the systematic review and were pertinent to the development of the recommendations. Because of the paucity of high-quality evidence, recommendations are based on expert consensus.

RECOMMENDATIONS

Recommendations for specific organ system-based toxicity diagnosis and management are presented. While management varies according to the organ system affected, in general, ICPi therapy should be continued with close monitoring for grade 1 toxicities, except for some neurologic, hematologic, and cardiac toxicities. ICPi therapy may be suspended for most grade 2 toxicities, with consideration of resuming when symptoms revert ≤ grade 1. Corticosteroids may be administered. Grade 3 toxicities generally warrant suspension of ICPis and the initiation of high-dose corticosteroids. Corticosteroids should be tapered over the course of at least 4-6 weeks. Some refractory cases may require other immunosuppressive therapy. In general, permanent discontinuation of ICPis is recommended with grade 4 toxicities, except for endocrinopathies that have been controlled by hormone replacement. Additional information is available at www.asco.org/supportive-care-guidelines.

Mechanisms of Immune Checkpoint Inhibitor-Mediated Colitis

Immune checkpoint inhibitors (ICIs) have provided tremendous clinical benefit in several cancer types. However, systemic activation of the immune system also leads to several immune-related adverse events. Of these, ICI-mediated colitis (IMC) occurs frequently and is the one with the highest absolute fatality. To improve current treatment strategies, it is important to understand the cellular mechanisms that induce this form of colitis. In this review, we discuss important pathways that are altered in IMC in mouse models and in human colon biopsy samples. This reveals a complex interplay between several types of immune cells and the gut microbiome. In addition to a mechanistic understanding, patients at risk should be identifiable before ICI therapy. Here we propose to focus on T-cell subsets that interact with bacteria after inducing epithelial damage. Especially, intestinal resident immune cells are of interest. This may lead to a better understanding of IMC and provides opportunities for prevention and management.

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.

Drug-Induced Colitis

Drug-induced colitis encompasses a wide spectrum of colon disorders that can manifest microscopically or macroscopically. Patients present with new-onset colitis or exacerbations of inflammatory bowel diseases; in some cases, colitis resolves with discontinuation of medication. Mucosal injury can be focal or extensive, involving the entire colonic mucosa, and sometimes involves other parts of the gastrointestinal tract. It has been a challenge to determine the proportion of new-onset colitis caused by medication and there are few data on the overall prevalence. We review the drugs that have been linked with development of drug-induced colitis and strategies for physicians who believe their patients have this disorder-usually discontinuation of the drug believed to cause colitis and treatment with steroids or immune-modulating therapies. Physicians must be aware of medications that can cause colitis.

The gut microbiome and efficacy of cancer immunotherapy

Cancer treatment has been deeply changed by immunotherapy, achieving unprecedented improvement in overall and progression-free survival in several advanced and metastatic cancers. Currently, immune checkpoint inhibitor (ICI) antibodies against cytotoxic T-lymphocyte antigen (CTLA-4) and programmed death/ligand 1 (PD-1/PD-L1) are being tested and approved for different tumors, ranging from melanoma to lung carcinoma. However, only a subgroup of patients can reach treatment benefits and long-term responses, and reliable biomarkers that can accurately predict clinical responses to immunotherapy are still unidentified. In the last decade, accumulating evidence seems to suggest the gut microbiota as one of the modulators that can alter the efficacy and toxicity of immunotherapy drugs (as well as chemotherapeutics), mainly acting through the local and systemic immune system. Herein, we reviewed the highly dynamic and complex microbiome-immune system interface, its bidirectional relationship with cancer immunotherapies, and explored the future possibilities and risks in manipulating the gut microbiome.

Immune checkpoint inhibitor-mediated colitis in gastrointestinal malignancies and inflammatory bowel disease

Immune checkpoint inhibitors (ICI) have markedly changed the landscape of cancer therapy. By re-invigorating the immune system against tumors, ICI provide novel therapeutic options for a broad variety of malignancies, including many gastrointestinal (GI) cancers. However, these therapies can also induce autoimmune-like side effects in healthy tissue across the body. One of the most common of these side effects is ICI-mediated colitis and diarrhea (IMC). Here, we review the incidence and risk of IMC in ICI therapy, with a focus on what is known regarding IMC in patients with GI malignancies. We also discuss data available on the use of ICI and risk of IMC in patients with pre-existing inflammatory bowel disease, as these patients may have increased risk of IMC due to their underlying intestinal pathology.

Structural Characterization of a Macrocyclic Peptide Modulator of the PD-1/PD-L1 Immune Checkpoint Axis

The clinical success of PD-1/PD-L1 immune checkpoint targeting antibodies in cancer is followed by efforts to develop small molecule inhibitors with better penetration into solid tumors and more favorable pharmacokinetics. Here we report the crystal structure of a macrocyclic peptide inhibitor (peptide 104) in complex with PD-L1. Our structure shows no indication of an unusual bifurcated binding mode demonstrated earlier for another peptide of the same family (peptide 101). The binding mode relies on extensive hydrophobic interactions at the center of the binding surface and an electrostatic patch at the side. An interesting sulfur/π interaction supports the macrocycle-receptor binding. Overall, our results allow a better understanding of forces guiding macrocycle affinity for PD-L1, providing a rationale for future structure-based inhibitor design and rational optimization.

Diagnosis and Management of Immune Checkpoint Inhibitor Colitis

Increased use of immune checkpoint inhibitors (ICIs) has created a rise in immune-related adverse events (irAEs), which may affect any system in the body. Gastrointestinal (GI) irAEs such as immune-mediated colitis are common, occurring in 35% to 50% of patients receiving ICIs. GI irAEs usually develop 6 to 8 weeks after ICI initiation and can involve any part of the GI system. Patients with immune-mediated colitis are categorized into 1 of 5 grades based on the National Cancer Institute's Common Terminology Criteria for Adverse Events, which also guide treatment decisions. An infectious cause for the diarrhea should be excluded in all patients. Patients with grade 1 symptoms are managed conservatively. Patients with grade 2 or higher symptoms should undergo a colonoscopy and are treated with systemic corticosteroids and, depending on their response, biologic therapy. The aim of this article is to review the diagnosis and management of patients with immune-mediated colitis, which should be identified early and addressed promptly to avoid detrimental outcomes.

Inhibitors of immune checkpoints-PD-1, PD-L1, CTLA-4-new opportunities for cancer patients and a new challenge for internists and general practitioners

The treatment of cancer patients with immune checkpoint inhibitors (ICI) (anti-CTLA-4, anti-PD-1, anti-PD-L1, combined therapy anti-PD-1/PD-L1 with anti-CTLA-4) has without doubt been a significant breakthrough in the field of oncology in recent years and constitutes a major step forward as a novel type of immunotherapy in the treatment of cancer. ICIs have contributed to a significant improvement in the outcome of treatment and prognosis of patients with different types of malignancy. With the expansion of the use of ICIs, it is expected that caregivers will face new challenges, namely, they will have to manage the adverse side effects associated with the use of these drugs. New treatment options pose new challenges not only for oncologists but also for specialists in other clinical fields, including general practitioners (GPs). They also endorse the need for taking a holistic approach to the patient, which is a principle widely recognized in oncology and especially relevant in the case of the expanding use of ICIs, which may give rise to a wide variety of organ complications resulting from treatment. Knowledge and awareness of the spectrum of immune-related adverse events (irAEs) will allow doctors to qualify patients for treatment more appropriately, prevent complications, correctly recognize, and ultimately treat them. Additionally, patients with more non-specific symptoms would be expected, in the first instance, to consult their general practitioners, as complications may appear even after the termination of treatment and do not always proceed in line with disease progression. Dealing with any iatrogenic complications, will not only be the remit of oncologists but because of the likelihood that specific organs may be affected, is likely to extend also to specialists in various fields of internal medicine. These specialists, e.g., endocrinologists, dermatologists, pulmonologists, and gastroenterologists, are likely to receive referrals for patients suffering from specific types of adverse events or will be asked to provide care in cases requiring hospitalization of patients with complications in their field of expertise. In view of these considerations, we believe that there is an urgent need for multidisciplinary teamwork in the treatment of cancer patients undergoing immunotherapy and suffering the consequent adverse reactions to treatment.

Fecal calprotectin as a predictor of gastrointestinal immune-related adverse events (CF-19): A prospective study

Background: Colitis is a frequent immune-related toxicity, without any biomarker that may predict its onset. It is endoscopically similar to intestinal inflammatory diseases, where fecal calprotectin (FC) is used as a biomarker to early-detect a relapse. We found contradictory evidence about FC and immunotherapy and no prospective study was already published.   Methods: We present an analytical, observational and prospective study of one year’s duration. We analyzed FC basal, and then prior to each cycle until the sixth, ending with quarterly follow-up. For evaluating the predictive value of FC we estimated the area under the ROC curve for basal absolute values and for each cycle, and calculated its relative percentage change with respect to basal. We also planned to estimate sensitivity, specificity and predictive values indexes for different cut-off points. Because of lack of recruitment we did a preliminary analysis at the end of the initially estimated period before suggesting its prolongation.   Results: 24 patients (19 male) were included in the study. This included n=15 diagnosed with lung cancer, head and neck, renal, bladder and colorectal cancer (n=2, each), and melanoma (n=1). They were treated with Anti PD-1/PDL-1 mono therapy (n=18), combo with chemo (n=2), or combo with anti-CTLA4 (n=2). Three patients had G1 colitis and two, >=G2, all treated with anti-PD1 and before 6th cycle, as described on literature. ROC curve presents AUC 0,559 (CI95%:0,32-0,798) and RR for colitis taking FC value is 1,001 for each 10 units (p=0,493).   Conclusion: Even though we must take into account the limitations of the study we cannot conclude that FC could be used as a predictor for detecting immune-mediated colitis.

Sargramostim and immune checkpoint inhibitors: combinatorial therapeutic studies in metastatic melanoma

The use of immune checkpoint inhibitors in patients with metastatic melanoma generates clinical benefit, including improved survival. Yet disease resistance and immune-related adverse events persist as unmet needs. Sargramostim, a yeast-derived recombinant human GM-CSF, has shown clinical activity against diverse solid tumors, including metastatic melanoma. Here we review the use of sargramostim for treatment of advanced melanoma. Potential sargramostim applications in melanoma draw on the unique ability of GM-CSF to link innate and adaptive immune responses. We review preclinical and translational data describing the mechanism of action of sargramostim and synergy with immune checkpoint inhibitors to enhance efficacy and reduce treatment-related toxicity.