Cytomegalovirus reactivation in patients with refractory checkpoint inhibitor-induced colitis

Influence of high-fiber diet on ipilimumab-induced gastrointestinal toxicity in metastatic melanoma

BACKGROUND

The anti-cytotoxic T-lymphocyte-associated protein (CTLA)-4 antibody ipilimumab (ipi) and the anti-programmed death (PD)-1 antibody nivolumab (nivo) are routinely used to treat metastatic melanoma. One of the most frequent severe immune-related adverse events (irAEs) induced by ipi is diarrhea as a symptom of ir-colitis. Here, the composition of the gut microbiome was shown to correlate with the risk of developing colitis. Stimulated by a patient case and the knowledge that nutrition influences the gut microbiome, we performed a retrospective analysis to evaluate dietary habits and the frequency of colitis in patients with ipi ± nivo therapy.

METHODS

Patients with metastasized stage III or IV melanoma who were treated with ipi ± nivo and who were willing to take part in a nutritional survey and interview at least three months after the first ipi dose were included into the study. Dietary habits were investigated using the food frequency questionnaire (FFQ) and personal interviews. The calculated daily intake of calories, carbohydrates, fats, proteins, sugars, and dietary fiber was correlated with the development of ir-colitis.

RESULTS

20 patients were included into this study, and all but one received ipi-nivo combination therapy. The median age was 59.5 years, and 60 % were male. 4 of 20 patients (20 %) developed ir-colitis grade 3 after two cycles in the median and were managed with at least high-dose corticosteroids. The FFQ and interview were conducted in a median of six months after treatment initiation. In general, the interviewed patients followed a typical western-pattern diet based on carbohydrates as the main, followed by fat as the second most important energy substrate. Comparing patients with and without colitis our investigation revealed that the achieved amount of recommended dietary fiber intake per total energy intake (TEI) was negatively associated with diarrhea and colitis (p = 0.061). No significant differences concerning daily intake of calories, carbohydrates, fats, proteins, and sugar were found. In addition, no significant differences were found among patients in terms of their age, gender, tobacco use, supplement intake, therapy regime, or body mass index (BMI).

CONCLUSIONS

This pilot study gives first hints that nutritional habits might influence treatment tolerability to ipi ± nivo therapy. A high-fiber diet might protect against ir-colitis and diarrhea in ipi-treated patients. This observation should be validated by a prospective randomized interventional trial. However, if it is possible to prevent ir-colitis by a high-fiber diet that would be of great impact on routine patient treatment.

Faricimab-Associated Intraocular Inflammation With Features of Herpes Simplex Virus

OBJECTIVE

Faricimab-associated intraocular inflammation (IOI) is an emerging concern. We aimed to investigate clinical features, management, and outcomes of severe IOI following faricimab therapy, with particular attention to cases displaying features consistent with herpes simplex virus (HSV) involvement.

DESIGN

Single-center retrospective interventional case series.

SUBJECTS

Five patients (5 eyes) who developed severe IOI following intravitreal faricimab injection for neovascular age-related macular degeneration (nAMD, n = 4) or diabetic macular edema (DME, n = 1) between June 2023 and October 2024. The nAMD patients had received a mean of 17.75 ± 9.18 prior anti-VEGF injections (range 6-26 injections). The DME patient had previously received 7 aflibercept injections and 2 dexamethasone implants. Prior to faricimab, 3 patients were being treated with aflibercept and 2 with ranibizumab biosimilar.

METHODS

Medical records were reviewed for clinical features, treatment approaches, and outcomes. Cases were identified through systematic review of follow-up appointments and urgent care presentations. When clinically indicated, additional investigations including optical coherence tomography and fluorescein angiography were performed.

MAIN OUTCOME MEASURES

Best-corrected visual acuity (BCVA), intraocular pressure (IOP), anterior chamber (AC) inflammation, presence of keratic precipitates (KPs), vitreous cells, signs of viral reactivation, and treatment response.

RESULTS

The median number of faricimab injections before inflammation was 5 (range 3-13). Mean interval between injection and symptom onset was 16.8 days (range 1-35). All patients presented with AC inflammation and elevated IOP (mean 32.8 ± 4.15 mmHg, range 28-38 mmHg). All patients demonstrated features consistent with HSV keratouveitis, including dendritic ulcers, reduced corneal sensation, and granulomatous KPs. Treatment included topical or systemic steroids in all cases, with 4 patients (80%) receiving concurrent antiviral therapy. Median time to inflammation resolution was 15.5 days. Four patients (80%) did not recover baseline vision.

CONCLUSIONS

This case series identifies a previously unreported association between faricimab-associated IOI and features of viral reactivation. The temporal relationship including onset patterns suggestive of delayed hypersensitivity, alongside consistent HSV features and favourable antiviral response, suggests a possible mechanism linked to VEGF-A and Ang-2 mediated alterations in ocular immune surveillance. While further investigation is needed to establish causality, clinicians should consider viral mechanisms when evaluating and treating these cases.

Immune-mediated colitis after immune checkpoint inhibitor therapy

Immune checkpoint inhibitors (ICIs) have led to improved outcome in patients with various types of cancer. Due to inhibition of physiological anti-inflammatory mechanisms, patients treated with ICIs may develop autoimmune inflammation of the colon, associated with morbidity, decreased quality of life (QoL), and mortality. In this review, we summarize clinical and pathophysiological aspects of immune-mediated colitis (ImC), highlighting novel treatment options. In the colon, ICIs trigger resident and circulating T cell activation and infiltration of myeloid cells. In addition, the gut microbiota critically contribute to intestinal immune dysregulation and loss of barrier function, thereby propagating local and systemic inflammation. Currently available therapies for ImC include corticosteroids, antitumor necrosis factor-α (TNF-α)- and anti-integrin α4β7 antibodies. Given that systemic immunosuppression might impair antitumor immune responses, novel therapeutic approaches are urgently needed.

Early identification and multidisciplinary management of immune checkpoint inhibitors associated colitis can improve patient outcomes

Currently, the use of immune checkpoint inhibitors (ICIs) has shown notable clinical efficacy in treating various malignant tumors, significantly improving patient prognosis. However, while ICIs enhance the body's anti-tumor effects, they can also trigger immune-related adverse events (irAEs), with ICI-associated colitis being one of the more prevalent forms. This condition can disrupt treatment, necessitate drug discontinuation, and adversely affect therapeutic outcomes. In severe cases, irAEs may even become life-threatening. A recent case report by Hong et al highlights the importance of vigilance for ICI-associated colitis in patients experiencing symptoms such as diarrhea and abdominal pain, which can arise both during and even after completion of ICI treatment. Early identification, multidisciplinary management, and continuous monitoring of patients are essential steps to further improve outcomes.

What should intensivists know about immune checkpoint inhibitors and their side effects?

The pharmacological group of immune checkpoint-inhibitors (ICI) has revolutionized the field of oncology in the last ten years. The improvements in the survival of certain cancers thanks to these treatments comes at the cost of an increased morbidity and mortality due to certain immune related adverse events (irAE). This review will concentrate on the irAE that more frequently require intensive care unit (ICU) admission. The infectious burden of patients treated with ICI is also explored, shining light not only on the infections caused by the immunosuppression needed to manage the different irAE, but also on the specific infections arising from a unique immune dysregulation only seen in ICI treated patients.

Systematic review of immune checkpoint inhibitor-related gastrointestinal, hepatobiliary, and pancreatic adverse events

Gastrointestinal immune-related adverse events (GI irAEs) are common manifestations of immune checkpoint inhibitor (ICI) toxicity. We present a comprehensive systematic review of the incidence, management, and clinical course of irAEs across the entire GI system, including the luminal GI tract, liver, and pancreas. MEDLINE, Embase, Web of Science Core Collection, and Cochrane Library were used to conduct this review. All studies pertaining to GI irAEs were included. Both abstracts and full manuscripts were eligible if they included human subjects and were written in the English language. Articles not available in English, animal studies, or research not specific to GI toxicity of immunotherapy were excluded. We excluded certain article types depending on whether stronger evidence was available in the literature for a specific toxicity, for example, if prospective studies were available on a topic, retrospective studies and case reports were excluded. We extracted a final 166 articles for our review and followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for data reporting. Risk of bias tools were not used to evaluate the extracted studies given the narrative nature of this manuscript, but each study was critically appraised by the manuscript writer. We detail the incidence, presentation, evaluation, management, and outcomes of the various GI toxicities that may arise with ICI therapy. Specifically, we discuss the characteristics of upper GI toxicity (esophagitis and gastroenteritis), lower GI toxicity (colitis), hepatobiliary inflammation, pancreatitis, and rarer forms of GI toxicity. We hope this review serves as a useful and accessible clinical tool that helps physicians familiarize themselves with the nuances of gastrointestinal/hepatic/pancreatic ICI toxicity diagnosis and management.

Focus on Immune Checkpoint Inhibitors-related Intestinal Inflammation: From Pathogenesis to Therapeutical Approach

Recently, antitumor immunotherapies have witnessed a breakthrough with the emergence of immune checkpoint inhibitors (ICIs) including programmed cell death-1 (PD-1), programmed cell death-ligand 1 (PD-L1), and cytotoxic T lymphocyte antigen 4 (CTLA-4) inhibitors. Unfortunately, the use of ICIs has also led to the advent of a novel class of adverse events that differ from those of classic chemotherapeutics and are more reminiscent of autoimmune diseases, the immune-related adverse events (IRAEs). Herein, we performed an insight of the main IRAEs associated with ICIs, focusing on gastroenterological IRAEs and specifically on checkpoint inhibitor colitis, which represents the most widely reported IRAE to date. We comprehensively dissected the current evidence regarding pathogenesis, diagnosis, and management of ICIs-induced colitis, touching upon also on innovative therapies.

Two Cases of Cytomegalovirus Colitis During the Treatment of Immune Checkpoint Inhibitor-Associated Colitis

Herein, we outlined two case reports of patients who developed cytomegalovirus colitis following the initiation of corticosteroid therapy for colitis as a result of immune-related adverse events (irAEs). For both patients, endoscopic findings were similar to those observed for patients with irAE colitis but were devoid of the characteristic features associated with cytomegalovirus colitis, including punched-out ulcers. Given the therapeutic disparities between these two conditions, it is imperative to distinguish between these conditions in clinical practice. When addressing exacerbations or refractory manifestations of irAE-associated colitis, clinicians should remain vigilant with regard to the potential for cytomegalovirus infection, even in the absence of punched-out ulcers in the colorectum.

Management of liver and gastrointestinal toxicity induced by immune checkpoint inhibitors: Position statement of the AEEH-AEG-SEPD-SEOM-GETECCU

The development of the immune checkpoint inhibitors (ICI) is one of the most remarkable achievements in cancer therapy in recent years. However, their exponential use has led to an increase in immune-related adverse events (irAEs). Gastrointestinal and liver events encompass hepatitis, colitis and upper digestive tract symptoms accounting for the most common irAEs, with incidence rates varying from 2% to 40%, the latter in patients undergoing combined ICIs therapy. Based on the current scientific evidence derived from both randomized clinical trials and real-world studies, this statement document provides recommendations on the diagnosis, treatment and prognosis of the gastrointestinal and hepatic ICI-induced adverse events.

Management of liver and gastrointestinal toxicity induced by immune checkpoint inhibitors: Position statement of the AEEH-AEG-SEPD-SEOM-GETECCU

The development of the immune checkpoint inhibitors (ICI) is one of the most remarkable achievements in cancer therapy in recent years. However, their exponential use has led to an increase in immune-related adverse events (irAEs). Gastrointestinal and liver events encompass hepatitis, colitis and upper digestive tract symptoms accounting for the most common irAEs, with incidence rates varying from 2 % to 40 %, the latter in patients undergoing combined ICIs therapy. Based on the current scientific evidence derived from both randomized clinical trials and real-world studies, this statement document provides recommendations on the diagnosis, treatment and prognosis of the gastrointestinal and hepatic ICI-induced adverse events.

Treatment and outcomes of immune checkpoint inhibitors-associated colitis/diarrhea: A systematic review and meta-analysis

BACKGROUND

Immune checkpoint inhibitors (ICIs) have improved the outcomes of cancer patients. However, ICIs often lead to colitis/diarrhea. This study aimed to assess the treatment of ICIs-associated colitis/diarrhea and outcomes.

METHODS

PubMed, EMBASE, and Cochrane Library databases were searched for eligible studies which investigated the treatment and outcomes of colitis/diarrhea developing in patients who received ICIs. The pooled incidences of any-grade colitis/diarrhea, low-grade colitis, high-grade colitis, low-grade diarrhea, and high-grade diarrhea as well as the pooled rates of response to treatment, mortality, and ICIs permanent discontinuation and restarts in patients with ICIs-associated colitis/diarrhea were estimated using a random-effects model.

RESULTS

Among the 11,492 papers initially identified, 27 studies were included. The pooled incidences of any-grade colitis/diarrhea, low-grade colitis, high-grade colitis, low-grade diarrhea, and high-grade diarrhea were 17%, 3%, 17%, 13%, and 15%, respectively. The pooled rates of overall response, response to corticosteroid therapy, and response to biological agents were 88%, 50%, and 96%, respectively. The pooled short-term mortality in patients with ICIs-associated colitis/diarrhea was 2%. The pooled incidences of ICIs permanent discontinuation and restarts were 43% and 33%, respectively.

CONCLUSION

ICIs-associated colitis/diarrhea is common, but rarely lethal. Half of them are responsive to corticosteroid therapy. There is a fairly high rate of response to biological agents in steroid-refractory colitis/diarrhea patients.

Case Report: Toripalimab: a novel immune checkpoint inhibitor in advanced nasopharyngeal carcinoma and severe immune-related colitis

Toripalimab, a specific immune checkpoint inhibitor targeting the programmed death 1 (PD-1) receptor, represents a novel immunotherapeutic approach for advanced nasopharyngeal carcinoma, showing promising curative potential. However, it is not without drawbacks, as some patients experience immune-related adverse events (irAEs) associated with this treatment, and there remains a limited body of related research. Here, we present a case of advanced nasopharyngeal carcinoma in a patient who developed colitis as an irAE attributed to Toripalimab. Subsequent to Toripalimab treatment, the patient achieved complete remission. Notably, the development of colitis was accompanied by inflammatory manifestations evident in colonoscopy and pathology results. Further investigation revealed cytomegalovirus (CMV) infection, detected through immunohistochemistry in 11 colon biopsies. Subsequent treatment with ganciclovir and steroids resulted in symptom relief, and colonoscopy indicated mucosal healing. Our case highlights the association between irColitis induced by Toripalimab and CMV infection. Toripalimab demonstrates remarkable efficacy in treating advanced nasopharyngeal carcinoma, albeit with a notable risk of irAEs, particularly in the form of colitis. The link between symptoms and endoscopic pathology findings in irColitis is noteworthy. Standardized biopsy procedures can effectively confirm the diagnosis of CMV infection. Our findings may provide valuable guidance for managing acute CMV infection and irAEs associated with Toripalimab in the treatment of nasopharyngeal carcinoma in the future.

[Cytomegalovirus reactivation in patients with immune-mediated gastritis]

INTRODUCTION

Reactivation of cytomegalovirus can complicate the evolution of patients with gastritis induced by immune checkpoint inhibitors.

METHODS

The experience in our center is described and a review of the literature is performed.

RESULTS

A case of severe gastritis induced by treatment with a programmed cell death receptor-1 (anti-PD1) inhibitor, associated with reactivation of cytomegalovirus (CMV) is described. In the systematic review, we identified 5 cases of immune-related gastritis associated with CMV reactivation. Ganciclovir treatment contributed to clinical improvement in most patients.

CONCLUSION

The early identification of a CMV infection in patients with severe or refractory immune-related gastritis will allow the initiation of targeted treatment, and may avoid increasing immunosuppressive therapy.

Characteristics and usefulness of transabdominal ultrasonography in immune-mediated colitis

BACKGROUND/AIMS

The usefulness of ultrasonography (US) in diseases of the gastrointestinal tract has been reported recently. This prospective study aimed to determine the features of US findings in immune-mediated colitis (IMC), an adverse event induced by immune checkpoint inhibitor, and examine the correlation between US findings, colonoscopy (CS) findings, and severity of colitis.

METHODS

We studied patients examined using CS and US upon suspicion of IMC in Hokkaido University Hospital between April 2018 and February 2021. Endoscopic findings of IMC were assessed using the Ulcerative Colitis Endoscopic Index of Severity (UCEIS). The severity of US findings in IMC was evaluated using US grade, which is the ultrasonographic grading scale in ulcerative colitis. Bowel wall thickness and the intensity of the color Doppler signal were also analyzed. Severity of colitis was evaluated using Common Terminology Criteria for Adverse Events (CTCAE) grade version 5.

RESULTS

Fourteen patients with IMC were enrolled. The US findings were bowel wall thickening, loss of stratification, ulceration and increased blood flow signal. The US grade was moderately correlated with the UCEIS (r=0.687, p=0.009) and CTCAE grade (r=0.628, p=0.035). Bowel wall thickness and UCEIS (r=0.628, p=0.020), as well as color Doppler signal grade and CTCAE grade (r=0.724, p=0.008), were significantly correlated.

CONCLUSIONS

US findings in IMC were mainly similar to those of ulcerative colitis, but there were some findings that were characteristic only of IMC. Significant correlation was found between US findings, CS findings, and severity of colitis. Hence, US could be useful for the evaluation of IMC.

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.

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.

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.

Infections due to dysregulated immunity: an emerging complication of cancer immunotherapy

Immune checkpoint inhibitors (ICIs) have revolutionised cancer treatment. However, immune-related adverse events (irAEs) are a common side effect which can mimic infection. Additionally, treatment of irAEs with corticosteroids and other immunosuppressant agents can lead to opportunistic infection, which we have classed as immunotherapy infections due to immunosuppression. However, emerging reports demonstrate that some infections can be precipitated by ICIs in the absence of immunosuppressive treatment, in contrast to the majority of reported cases. These infections are characterised by a dysregulated inflammatory immune response, and so we propose they are described as immunotherapy infections due to dysregulated immunity. This review summarises the rapidly emerging evidence of these phenomena and proposes a new framework for considering infection in the context of cancer immunotherapy.

Immune Checkpoint Inhibitor-associated Diarrhea and Colitis: A Systematic Review and Meta-analysis of Observational Studies

BACKGROUND

Immune checkpoint inhibitors (ICIs) have transformed the management of advanced malignancies but are associated with diarrhea and colitis. The objective of our systematic review and meta-analysis was to determine the incidence and outcomes of ICI-associated diarrhea and colitis. Bibliographic databases were searched through August 13, 2019, for observational studies of ICI therapy reporting the incidence and/or treatment of diarrhea or colitis. The primary outcome was ICI-associated diarrhea and colitis. Meta-analyses were performed with random-effects models. Twenty-five studies (N=12,661) were included. All studies had a high risk of bias in at least 1 domain. The overall incidence of diarrhea/colitis was 12.8% [95% confidence interval (CI), 8.8-18.2, I2=96.5]. The incidence was lower in patients treated with anti-programmed cell death 1/programmed death-ligand 1 (4.1%, 95% CI, 2.6-6.5) than in those treated with anti-cytotoxic T-cell lymphocyte-associated antigen 4 (20.1%, 95% CI, 15.9-25.1). The remission of diarrhea and/or colitis was higher in patients treated with corticosteroids plus biologics (88.4%, 95% CI, 79.4-93.8) than in those treated with corticosteroids alone (58.3%, 95% CI, 49.3-66.7, Q=18.7, P<0.001). ICI were permanently discontinued in 48.1% of patients (95% CI, 17.8-79.1). ICI were restarted after temporary interruption in 48.6% of patients (95% CI, 18.2-79.4) of whom 17.0% (95% CI, 6.4-30.0) experienced recurrence. Real-world incidence of ICI-associated diarrhea/colitis exceeds 10%. These events lead to permanent ICI discontinuation in just over 50% of patients, while <20% have recurrence of symptoms if ICI are resumed. Further studies are needed to identify patients who would benefit from early treatment with biologics as well as appropriate patients to resume ICI therapy.

Viral Molecular Mimicry Influences the Antitumor Immune Response in Murine and Human Melanoma

Molecular mimicry is one of the leading mechanisms by which infectious agents can induce autoimmunity. Whether a similar mechanism triggers an antitumor immune response is unexplored, and the role of antiviral T cells infiltrating the tumor has remained anecdotal. To address these questions, we first developed a bioinformatic tool to identify tumor peptides with high similarity to viral epitopes. Using peptides identified by this tool, we demonstrated that, in mice, preexisting immunity toward specific viral epitopes enhanced the efficacy of cancer immunotherapy via molecular mimicry in different settings. To understand whether this mechanism could partly explain immunotherapy responsiveness in humans, we analyzed a cohort of patients with melanoma undergoing anti-PD1 treatment who had a high IgG titer for cytomegalovirus (CMV). In this cohort of patients, we showed that high levels of CMV-specific antibodies were associated with prolonged progression-free survival and found that, in some cases, peripheral blood mononuclear cells (PBMC) could cross-react with both melanoma and CMV homologous peptides. Finally, T-cell receptor sequencing revealed expansion of the same CD8⁺ T-cell clones when PBMCs were expanded with tumor or homologous viral peptides. In conclusion, we have demonstrated that preexisting immunity and molecular mimicry could influence the response to immunotherapies. In addition, we have developed a free online tool that can identify tumor antigens and neoantigens highly similar to pathogen antigens to exploit molecular mimicry and cross-reactive T cells in cancer vaccine development.

Herpesvirus Infections Potentiated by Biologics

Herpesviruses such as herpes simplex virus (HSV) type 1 and 2, varicella-zoster virus (VZV), and cytomegalovirus (CMV) maintain lifelong latency in the host after primary infection and can reactivate periodically either as asymptomatic viral shedding or as clinical disease. Immunosuppression, including biologic therapy, may increase frequency and severity of herpesvirus reactivation and infection. Licensed biologics are reviewed regarding their risks of potentiating HSV, VZV, and CMV reactivation and infection. Approaches to prophylaxis against HSV, VZV, and CMV infection or reactivation are discussed.

Predicting and Preventing Immune Checkpoint Inhibitor Toxicity: Targeting Cytokines

Cancer immunotherapies can successfully activate immune responses towards certain tumors. However, this can also result in the development of treatment-induced immune-related adverse events (irAEs) in multiple tissues. Growing evidence suggests that cytokine production in response to these therapeutics potentiates the development of irAEs and may have predictive value as biomarkers for irAE occurrence. In addition, therapeutic agents that inhibit cytokine activity can limit the severity of irAEs, and their use is being tested in the clinical setting. This review provides an in-depth analysis of strategies to uncouple the cytokine response, that precipitates irAEs following cancer immunotherapies, from the benefit gained in promoting antitumor immunity.

Efficacy and safety of Infliximab for steroid-resistant immune-related adverse events: A retrospective study

The present study investigated outcomes of infliximab (IFX) treatment among 8 Japanese patients with various types of cancer (4 with malignant melanoma, 3 with lung cancer and 1 with renal cancer) who developed severe steroid-resistant immune-related adverse events (irAEs) in association with immune checkpoint inhibitors (ICIs) to determine its efficacy and safety. Information, including patient background, treatment progress, examination data and imaging data, was collected retrospectively from electronic medical records. Adverse reactions were evaluated using the Common Terminology Criteria for Adverse Events version 4.0. Specific ICIs used were anti-PD-1, anti-PD-L1 and anti-CTLA-4 antibody preparations in 7, 2 and 5 patients, respectively. Specific irAEs included grade 3 diarrhea/colitis in 7 patients and disseminated intravascular coagulation and myocarditis attributed to autoimmune activation in 1 patient. The median duration between systemic steroid and IFX treatments was 9 (range, 2-39) days. A total of 3 patients responded to IFX, 1 of whom responded after one dose and 2 responded after two doses. Respective diseases improved to grade 0 after a median of 18 (range, 9-32) days. No AEs were attributable to IFX. Additionally, anti-cytomegalovirus (CMV) and antibacterial agents were administered in parallel given the presence of CMV and Clostridium difficile (CD) infections in all patients, except in 1 exhibiting a marked IFX response after one dose. The combination of highly immunosuppressive IFX and high-dose systemic steroid administration over a long period presumably predisposed the patients to opportunistic enteric infections. Accordingly, early initiation of IFX treatment in conjunction with systemic steroid therapy should be considered for severe diarrhea/colitis and other irAEs. However, the possibility for CMV and CD infections should be recognized, and for these the treatment strategy may need to be modified at an early stage.

Virus-specific memory T cell responses unmasked by immune checkpoint blockade cause hepatitis

Treatment of advanced melanoma with combined PD-1/CTLA-4 blockade commonly causes serious immune-mediated complications. Here, we identify a subset of patients predisposed to immune checkpoint blockade-related hepatitis who are distinguished by chronic expansion of effector memory CD4⁺ T cells (T_EM cells). Pre-therapy CD4⁺ T_EM cell expansion occurs primarily during autumn or winter in patients with metastatic disease and high cytomegalovirus (CMV)-specific serum antibody titres. These clinical features implicate metastasis-dependent, compartmentalised CMV reactivation as the cause of CD4⁺ T_EM expansion. Pre-therapy CD4⁺ T_EM expansion predicts hepatitis in CMV-seropositive patients, opening possibilities for avoidance or prevention. 3 of 4 patients with pre-treatment CD4⁺ T_EM expansion who received αPD-1 monotherapy instead of αPD-1/αCTLA-4 therapy remained hepatitis-free. 4 of 4 patients with baseline CD4⁺ T_EM expansion given prophylactic valganciclovir and αPD-1/αCTLA-4 therapy remained hepatitis-free. Our findings exemplify how pathogen exposure can shape clinical reactions after cancer therapy and how this insight leads to therapeutic innovations.

Clinical types of checkpoint inhibitor-related pneumonitis in lung cancer patients: a multicenter experience

Background

Checkpoint inhibitor-related pneumonitis (CIP) is not well classified according to clinical factors. We propose different clinical sub-types of CIP based on clinical factors and investigated the corresponding clinical features, treatments, and outcomes.

Methods

We conducted a multicenter retrospective study of patients with lung cancer (including non-small cell lung cancer and small cell lung cancer) who developed CIP. The clinical characteristics, radiologic features, treatments, and outcomes of CIP were analyzed.

Results

A total of 55 patients developed CIP and were classified into 3 groups as follows: 21 in the pure type (PT) group, 14 in the induced type (IT) group, and 20 in the mixed type (MT) group. The incidence of severe (grade 3–5) pneumonitis was significantly higher in the IT group than in the PT and MT groups (71.4% vs. 14.3% vs. 50.0%, P=0.002). Antiviral therapy was significantly more frequent in the IT group than in the PT and MT groups. Antibiotic therapy was administered in 23.8%, 71.4%, and 80.0% of patients with the PT, IT, and MT, respectively. The improvement time in the PT group was longer than that in the IT and MT groups (0.9 vs. 0.5 vs. 0.3 months, P=0.028). Patients with the PT had a better tumor response to immune checkpoint inhibitors (ICIs) than those with the other 2 types [overall response rate (ORR), 78% vs. 31% vs. 44%, P=0.027].

Conclusions

The clinical classification of CIP may favor strategies for treatments and predict the tumor response to ICIs.

Imaging Spectrum of Infections in the Setting of Immunotherapy and Molecular Targeted Therapy

Advances in genomics and immunology are revolutionizing our understanding and treatment of cancer with improved treatment outcomes and patient quality of life. With the increasing use of immunotherapy and molecular targeted therapy, a variety of unusual and/or opportunistic infections are also observed. A variety of factors including use of immunosuppression for immune-mediated adverse effects play an important role for increasing the likelihood of these infections and form the basis of this case-based review. Imaging features of infections arising in patients undergoing immunotherapy regimens have not been previously highlighted. Prompt recognition of the spectrum of mycobacterial, bacterial, invasive fungal and viral pathogens can potentially lead to reduction in the high morbidity and mortality in this patient population.

Systematic review with meta-analysis: effectiveness of anti-inflammatory therapy in immune checkpoint inhibitor-induced enterocolitis

BACKGROUND

Immune checkpoint inhibitors have revolutionised cancer treatment, but at the cost of off-target immune-mediated organ damage. This includes checkpoint inhibitor-induced enterocolitis which frequently requires hospitalisation and may be life-threatening. Empiric treatment typically includes corticosteroids and infliximab, although no large-scale studies have confirmed their effectiveness.

AIM

To investigate the effectiveness of anti-inflammatory therapy in checkpoint inhibitor-induced enterocolitis METHODS: We performed a systematic review and meta-analysis of studies reporting clinical outcomes of checkpoint inhibitor-induced enterocolitis in adult cancer patients treated with anti-inflammatory agents. We searched Medline, EMBASE, and the Cochrane library through April and extracted the proportion of patients responding to anti-inflammatory therapy. Variation in effect size was studied using a random-effects meta-regression analysis, with checkpoint inhibitor agent and tumour type as the variables.

RESULTS

Data were pooled from 1210 treated patients across 39 studies. Corticosteroids were effective in 59% (95% CI 54- 65) of patients, with response significantly more favourable in patients treated with anti-PD-1/L1 monotherapy, compared with anti-CTLA-4 containing regimens (78%, 95% CI 69-85 vs 56 %, 95% CI 49-63, P = 0.003), and more favourable in lung cancer patients compared with melanoma patients (88%, 95% CI 62-97 vs 55%, 95% CI 47-63, P = 0.04). Infliximab was effective in 81% (95% CI 73-87) of patients, and vedolizumab in 85% (95% CI 60-96).

CONCLUSION

Corticosteroids, infliximab and vedolizumab, are effective in the treatment of checkpoint inhibitor-induced enterocolitis. Checkpoint inhibitor regimen and cancer type were significant moderators in response to corticosteroid therapy.

Severe cytomegalovirus gastritis after pembrolizumab in a patient with melanoma

Immunotherapy has emerged as a standard of cancer treatment, with an increasing number of indications. Recently, opportunistic infections have been reported in several cases in which immunotherapy has led to an increased susceptibility to infection. The present case is the first report of cytomegalovirus (cmv) gastritis occurring in a patient with melanoma during immunotherapy without immune-related adverse events (iraes) and without the use of immunosuppressant agents. A 43-year-old woman presented with stage iii malignant melanoma. She underwent wide excision of skin, with lymph node dissection, and she started immunotherapy with a 3-week cycle of pembrolizumab. The patient demonstrated stable disease response, and no iraes were observed during her initial treatment courses. However, after the 9th treatment cycle, she began to experience epigastric pain that worsened significantly, requiring a visit to the emergency centre. Imaging by computed tomography (ct) and integrated positron-emission tomography/ct revealed severe diffuse gastroduodenitis with acute pancreatitis. Esophagogastroduodenoscopy showed diffuse oozing, hemorrhagic, edematous, and exfoliative mucosa involving the entire gastric wall, defined as acute hemorrhagic gastritis. Biopsies of the gastric wall revealed cmv infection. Those findings were consistent with a diagnosis of cmv gastritis, and the patient received antiviral therapy with ganciclovir. After treatment, she recovered enough to resume immunotherapy. This case report presents a rare occurrence of cmv gastritis related to immunotherapy. As more patients are treated with immunotherapy, incidences of cmv infections are expected to increase; a high index of clinical suspicion is therefore needed in symptomatic patients.

Epstein-Barr Virus-Positive Mucocutaneous Ulcers Complicate Colitis Caused by Immune Checkpoint Regulator Therapy and Associate With Colon Perforation

BACKGROUND & AIMS

Cancer therapy with immune checkpoint inhibitors can cause colitis and colon perforation. We investigated whether infection with Epstein Barr virus (EBV) associates with development and severity of colitis in patients receiving immune checkpoint inhibitor therapies.

METHODS

We performed a retrospective analysis of fixed colon tissues from 16 patients (12 men, 4 women, median age, 69.5 y) with colitis after immune checkpoint inhibitor therapy (9 patients treated with anti-CTLA4, 3 patients treated with anti-PD1, and 4 patients received a combination). Ten tissue samples were biopsies and 6 were collected during resection (4 surgeries for colon perforation). Patients were treated between 2010 and 2018 in the United Kingdom. The tissues were analyzed by pathology, in situ hybridization (to detect EBV-encoded small RNAs [EBERs]), and immunohistochemistry. Clinical data were also collected.

RESULTS

Colon tissues from 4 of the 13 patients who received anti-CTLA4 (alone or in combination, 4 with colon perforation) had EBV-positive lymphoproliferations that manifested as florid ulcers associated with polymorphous infiltrates containing EBV-positive blasts (CD30+ or CD30-negative, CD20+, CD3-negative, and EBER+), plasma cells (CD138+, CD20-negative, and EBER+ or EBER-negative), and small B cells (CD20+, CD3-negative, and EBER+ or EBER-negative), consistent with EBV-positive mucocutaneous ulcers (EBVMCUs). In analyses of biopsies collected from 2 patients with EBVMCUs over multiple time points, we found that earlier biopsies had no or only a few EBV-positive cells, whereas 1 later biopsy had EBVMCU and co-infection with cytomegalovirus. EBVMCUs were associated with steroid-refractory colitis (100% of EBV-positive patients vs 12.5% of EBV-negative patients; P = .008) and colon perforation (100% of EBV-positive patients vs no EBV-negative patients; P = .001).

CONCLUSIONS

We found that colon tissues from 4/13 patients with colitis after anti-CTLA4 therapy (4/6 patients who underwent resection and 4/4 patients with colon perforation) contained EBVMCUs. EBVMCUs seem to arise secondarily in areas of inflamed colon due to immunosuppressive treatment for colitis. EBVMCUs are associated with steroid-refractory colitis and colon perforation.

Cytomegalovirus infection as an underestimated trigger for checkpoint inhibitor-related pneumonitis in lung cancer: a retrospective study

OBJECTIVES

Checkpoint inhibitor-related pneumonitis (CIP) is a rare but potentially fatal complication of immune checkpoint inhibitors (ICIs). At present, the mechanism of CIP is not completely clear. Cytomegalovirus (CMV) infection is widespread in the population. Chemotherapy and radiotherapy can lead to the reactivation of CMV. We aimed to investigate the association between CMV infection and CIP.

MATERIALS AND METHODS

We retrospectively identified all lung cancer patients treated with ICIs at our institute from January 2016 to May 2020. The association between the development of CIP and CMV infection status was analyzed.

RESULTS

Among 251 cases analyzed, 29 (11.6%) patients with CIP were identified, of whom 12 (4.78%) cases had grade 3-4 CIP. All 12 patients with grade 3-4 pneumonitis were CMV-IgG-positive, indicating a previous CMV infection. Except for one CMV-DNA-positive patient, the other patients were CMV-DNA-negative. All but one patient was CMV pp65 antigen-positive, indicating an early reactivation of the virus. The histological features of CMV pneumonia were not found in all available lung tissues, including lung transplantation pathology in one patient and lung biopsies in three patients. Except for one patient who received delayed antiviral therapy, the symptoms improved after glucocorticoid combined with antiviral therapy.

CONCLUSIONS

The use of ICIs can restore the immune function and cause an immune response to CMV antigen while the infection is still latent. Our study suggests that CIP may be an immune reconstitution syndrome associated with CMV infection. CMV infection may represent a potentially important trigger for CIP. Patients with severe CIP should be vigilant against CMV infection. The early use of glucocorticoid combined with antiviral therapy is pivotal to good prognosis.

Immune Checkpoint Inhibitor-Mediated Diarrhea and Colitis: A Clinical Review

Immune-mediated diarrhea and colitis (IMDC) is among the most common immune-related adverse events in patients with cancer treated with immune checkpoint inhibitors (ICIs). Many factors will affect the risk of IMDC, including the type of ICI used, the type of underlying cancer, and patient characteristics. A recent study showed that preexisting inflammatory bowel disease significantly increases the risk of diarrhea and colitis with ICI treatment. In terms of management, early endoscopic evaluation improves clinical outcome by identifying high-risk patients who will benefit from early add-on immunosuppressants. Inflammatory markers, including fecal lactoferrin and calprotectin, are good screening tools to predict which patients are at risk for colitis. Calprotectin especially is associated with colitis outcome and can be used as a surrogate marker to follow treatment response. Corticosteroids remain the first-line medical treatment of IMDC management, and add-on therapy with vedolizumab or infliximab should be considered in selected patients. Fecal microbiota transplantation may be considered in refractory cases. The decision to resume ICI should be decided by balancing the risk of recurrent IMDC and the likelihood of benefiting from further ICI treatment. There is no clear evidence about whether the use of immunosuppressants will result in a worse cancer outcome. With emerging evidence, our understanding and management strategies are likely to evolve in the future.

Retrospective Analysis of Treatment and Complications of Immune Checkpoint Inhibitor-Associated Colitis: Histological Ulcerations as Potential Predictor for a Steroid-Refractory Disease Course

Background/Aims

Among the severe immune-related adverse events (irAEs) that occur with immune checkpoint inhibitor (ICI) therapy, colitis is the most frequent one. This study aimed at describing the experience from the largest gastroenterology unit in Switzerland with immune checkpoint inhibitor-associated colitis (ICIAC), its clinical presentation, management, and outcomes.

Methods

We performed a retrospective review of patients who were referred for the evaluation of ICIAC between January 2011 and October 2018 to the Division of Gastroenterology and Hepatology, University Hospital Zurich.

Results

Thirty-three patients with immune-related colitis grade 3 or 4 met the inclusion criteria and were analyzed in detail: All patients had diarrhea, 64% had abdominal pain, 42% had bloody stool, 27% had emesis, and 18% developed fever. In total, 33% were successfully treated with corticosteroids alone; 66% were steroid-refractory and treated with infliximab or vedolizumab. Two of these patients developed severe complications requiring surgery. All patients reached complete remission of ICIAC and its symptoms. At colonoscopy, ulcerations were seen in 37% of steroid-refractory versus 63% of steroid-responsive cases. Deep histological ulcerations invading the submucosa were only present in steroid-refractory cases.

Conclusion

ICIAC is a severe irAE which frequently requires high-dose steroids and a close follow-up due to deleterious complications. The detection of histologically diagnosed deep ulcerations may predict a steroid-refractory course and may warrant early application of infliximab. However, larger studies are required to confirm our findings.

CMV coinfection in treatment refractory immune checkpoint inhibitor colitis

As immune checkpoint inhibitors (ICIs) are increasingly used, clinicians are more frequently encountering the side effects of these therapies. ICIs have been implicated in numerous adverse effects against healthy tissues. We present a case of a patient who developed treatment refractory checkpoint inhibitor colitis. Following colonoscopy, it was discovered that this patient had cytomegalovirus (CMV) coinfection. This case report highlights the importance of undertaking an appropriate assessment, including endoscopic and histologic investigation, of patients with presumed ICI colitis. Accurately diagnosing a superimposed CMV colitis changes clinical management and can improve patient outcomes.

Immune-related adverse events of checkpoint inhibitors

Cancer immunotherapies have changed the landscape of cancer treatment during the past few decades. Among them, immune checkpoint inhibitors, which target PD-1, PD-L1 and CTLA-4, are increasingly used for certain cancers; however, this increased use has resulted in increased reports of immune-related adverse events (irAEs). These irAEs are unique and are different to those of traditional cancer therapies, and typically have a delayed onset and prolonged duration. IrAEs can involve any organ or system. These effects are frequently low grade and are treatable and reversible; however, some adverse effects can be severe and lead to permanent disorders. Management is primarily based on corticosteroids and other immunomodulatory agents, which should be prescribed carefully to reduce the potential of short-term and long-term complications. Thoughtful management of irAEs is important in optimizing quality of life and long-term outcomes.

Management of Patients With Immune Checkpoint Inhibitor-Induced Enterocolitis: A Systematic Review

Immune checkpoint inhibitors (ICIs) have improved the treatment of several cancers. These drugs increase T-cell activity and the antitumor immune response but also have immune-related adverse effects that can affect the gastrointestinal (GI) tract. These adverse effects have been observed in 7% to 30% of patients treated with ICIs. As the number of diseases treated with ICIs increases, gastroenterologists will see more patients with ICI-induced GI adverse events. We performed a systematic review of the incidence, risk factors, clinical manifestations, and management of the adverse effects of ICIs on the GI tract. Treatment with anti-cytotoxic T-lymphocyte-associated antigen-4 often causes severe enterocolitis, whereas treatment with inhibitors of programmed cell death 1 have less frequent and more diverse adverse effects. Management of patients with GI adverse effects of ICIs should involve first ruling out other disorders, followed by assessment of severity, treatment with corticosteroids, and rapid introduction of infliximab therapy for nonresponders.

Infectious Complications of Immune Checkpoint Inhibitors

The clearance of both tumors and microbes depends on highly coordinated immune responses that are sufficiently potent to kill malignant or microbial cells while avoiding immunopathology from an overly exuberant inflammatory response. A molecular understanding of the immune pathways that regulate these responses paved the way for the development of checkpoint inhibitors (CPIs) as a therapeutic strategy to boost endogenous antitumor immunity. CPIs have demonstrated survival benefits across a wide spectrum of cancers. While infectious complications of CPIs are uncommon, immune-related adverse events occur frequently and often require immunosuppressive therapies that increase the risk of infection.

Management Considerations for Immune Checkpoint Inhibitor-Induced Enterocolitis Based on Management of Inflammatory Bowel Disease

BACKGROUND

Immune checkpoint inhibitor therapy has significantly improved the outcomes of various advanced malignancies that were deemed unruly prior to its invention. Immune-mediated diarrhea and enterocolitis are among the most frequently encountered adverse events of immune checkpoint inhibitor therapy. Given the increasing use of these therapies in the treatment of an ever-growing number of malignancies, providing appropriate treatment for such adverse effects has become crucial.

METHODS

In this review, we summarize the current body of evidence concerning the management of immune-mediated diarrhea and enterocolitis. Additionally, management of immune-mediated diarrhea and enterocolitis is likened to that of inflammatory bowel disease, given the resemblance between both entities in pathogenesis and clinical features. Reviewing the literature raised several points regarding this devastating toxicity that still need further investigation by future efforts.

RESULTS

Endoscopic and histologic evaluation is pivotal in the assessment of immune-mediated diarrhea and enterocolitis and provides vital information regarding the severity of the disease to guide treatment. Corticosteroids are the main therapy for immune-mediated diarrhea and enterocolitis, with infliximab and vedolizumab as second-line agents. Recently, fecal microbiota transplantation has emerged as a treatment option for immune-mediated diarrhea and enterocolitis that is refractory to corticosteroids. Restarting immune checkpoint inhibitor therapy after resolution of immune-mediated diarrhea and enterocolitis carries a risk of recurrence that is mostly controllable with current immune-suppressive treatment.

CONCLUSIONS

Lastly, we propose a management algorithm for immune-mediated diarrhea and enterocolitis. Prospective research, preferably as collaborative efforts from oncology and gastroenterology specialists, is needed to refine the management of immune-mediated diarrhea and enterocolitis.

Diagnosis, monitoring, and management of adverse events from immune checkpoint inhibitor therapy

Immune checkpoint inhibitor therapy (icit) is now a standard of care for a variety of cancers in both the metastatic and adjuvant settings. As a result, an understanding of the timing, epidemiology, monitoring, diagnosis, and management of immune-related adverse events (iraes) associated with icit is imperative. This article reviews specific iraes by organ system, consolidating recommendations from multiple guidelines and incorporating data from case reports to highlight additional evolving therapeutic options for patients. Managing iraes requires early recognition, early intervention, and education of the patients and the multidisciplinary health care team alike. Given the durable responses observed with icit, and the irreversible nature of some of the iraes, further research into management of the sequelae of icit is required.

Combination immunotherapy with anti-PD-L1 antibody and depletion of regulatory T cells during acute viral infections results in improved virus control but lethal immunopathology

Combination immunotherapy (CIT) is currently applied as a treatment for different cancers and is proposed as a cure strategy for chronic viral infections. Whether such therapies are efficient during an acute infection remains elusive. To address this, inhibitory receptors were blocked and regulatory T cells depleted in acutely Friend retrovirus-infected mice. CIT resulted in a dramatic expansion of cytotoxic CD4+ and CD8+ T cells and a subsequent reduction in viral loads. Despite limited viral replication, mice developed fatal immunopathology after CIT. The pathology was most severe in the gastrointestinal tract and was mediated by granzyme B producing CD4+ and CD8+ T cells. A similar post-CIT pathology during acute Influenza virus infection of mice was observed, which could be prevented by vaccination. Melanoma patients who developed immune-related adverse events under immune checkpoint CIT also presented with expanded granzyme-expressing CD4+ and CD8+ T cell populations. Our data suggest that acute infections may induce immunopathology in patients treated with CIT, and that effective measures for infection prevention should be applied.

Checkpoint Inhibitor-Induced Colitis

Immune checkpoint inhibitors have revolutionized treatment and overall survival for several different types of cancer. Antibodies to cytotoxic T-lymphocyte-associated protein 4 and to programmed cell death protein 1 and its ligand enhance cytotoxic T-cell survival, thus augmenting antitumor action and consequently inducing immune-related adverse events, of which the most relevant is diarrhea and colitis. This review compiles recent data on pathophysiology, clinical manifestations, and treatment of immune-mediated colitis (IMC). The pathogenesis of IMC is not completely understood, but recent studies have focused on the role of regulatory T cells and interactions with the gut microbiome. While sharing similarities with inflammatory bowel disease, IMC is considered a distinct form of colitis with acute onset and rapid progression leading to potential complications including bowel perforation and death. Prompt recognition and management of IMC is imperative for optimal outcomes. Although prospective clinical trials are lacking to guide therapy, recent guidelines recommend early endoscopic evaluation to establish the diagnosis and prompt initiation of corticosteroids. Response to first-line therapy should be assessed early to determine the need of escalation to biologic agents. With treatment, most patients will experience full resolution of symptoms, and subsequent rechallenge with anti-programmed cell death protein 1 or anti-programmed death-ligand 1 inhibitors can be considered.

Cytomegalovirus Enterocolitis in a Patient with Refractory Immune-Related Colitis

Although most immune-related adverse events (irAEs) secondary to immune checkpoint inhibitors can be managed with immunosuppressive therapies; they can induce reactivation of infectious diseases, including cytomegalovirus (CMV). Here, we show a case of CMV enterocolitis during steroid therapy for an irAE. A 77-year-old man with unresectable malignant melanoma was treated with ipilimumab. He suffered from immune-related colitis (irColitis) and was treated with methylprednisolone. Although corticosteroids initially improved his symptoms, CMV reactivation occurred and colitis was exacerbated. Antiviral therapy improved his symptoms without augmenting the immunosuppressive therapy. CMV colitis should be considered when a patient with irColitis shows resistance to immunosuppressive therapy.

Clinically Relevant Immune Responses against Cytomegalovirus: Implications for Precision Medicine

Immune responses to human cytomegalovirus (CMV) can be used to assess immune fitness in an individual. Further to its clinical significance in posttransplantation settings, emerging clinical and translational studies provide examples of immune correlates of protection pertaining to anti-CMV immune responses in the context of cancer or infectious diseases, e.g., tuberculosis. In this viewpoint, we provide a brief overview about CMV-directed immune reactivity and immune fitness in a clinical context and incorporate some of our own findings obtained from peripheral blood or tumour-infiltrating lymphocytes (TIL) from patients with advanced cancer. Observations in patients with solid cancers whose lesions contain both CMV and tumour antigen-specific T-cell subsets are highlighted, due to a possible CMV-associated “bystander” effect in amplifying local inflammation and subsequent tumour rejection. The role of tumour-associated antibodies recognising diverse CMV-derived epitopes is also discussed in light of anti-cancer immune responses. We discuss here the use of anti-CMV immune responses as a theranostic tool—combining immunodiagnostics with a personalised therapeutic potential—to improve treatment outcomes in oncological indications.