Releasing the brake: safety profile of immune check-point inhibitors in non-small cell lung cancer

Management of immune check-point inhibitor-associated colitis in patients with advanced metastatic cancers: A review article

Immune check-point inhibitors (ICPi) are immunomodulating agents, which have revolutionized the management of advanced metastatic cancers. Being immunomodulating agents, they are predisposed to causing colitis. This descriptive review article emphasized on the management of ICPi-associated colitis in advanced metastatic cancers. We used PubMed, Google Scholar, Scopus, and Embase databases for literature review, and terminologies commonly searched were "management," "immune check-point inhibitors," "colitis," "metastatic," "cancers," "literature," and "review." We reviewed a total of 11 articles done in the last 15 years relevant to ICPi colitis and its management; all the articles showed that diarrhea and colitis are the most common adverse effects observed in patients on ICPi, but prior to establishing the diagnosis of ICPi-causing colitis, possibility of Clostridium difficle or cytomegalovirus infections should be ruled out. Once the diagnosis of ICPi colitis is established, treatment should be started depending upon the severity of colitis. In mild severity, discontinuation of ICPi can resolve the symptoms but, in most of the patients with moderate to high severity of colitis, corticosteroids are considered a cornerstone treatment. Patients unresponsive to steroid treatment should be re-evaluated for infections after which anti-TNF therapy-infliximab or vedolizumab, cyclosporine, mycophenolate mofetil-can be considered.

Autoimmune PaneLs as PrEdictors of Toxicity in Patients TReated with Immune Checkpoint InhibiTors (ALERT)

BACKGROUND

Immune-checkpoint inhibitors (ICI) can lead to immune-related adverse events (irAEs) in a significant proportion of patients. The mechanisms underlying irAEs development are mostly unknown and might involve multiple immune effectors, such as T cells, B cells and autoantibodies (AutoAb).

METHODS

We used custom autoantigen (AutoAg) microarrays to profile AutoAb related to irAEs in patients receiving ICI. Plasma was collected before and after ICI from cancer patients participating in two clinical trials (NCT03686202, NCT02644369). A one-time collection was obtained from healthy controls for comparison. Custom arrays with 162 autoAg were used to detect IgG and IgM reactivities. Differences of median fluorescent intensity (MFI) were analyzed with Wilcoxon sign rank test and Kruskal-Wallis test. MFI 500 was used as threshold to define autoAb reactivity.

RESULTS

A total of 114 patients and 14 healthy controls were included in this study. irAEs of grade (G) ≥ 2 occurred in 37/114 patients (32%). We observed a greater number of IgG and IgM reactivities in pre-ICI collections from patients versus healthy controls (62 vs 32 p < 0.001). Patients experiencing irAEs G ≥ 2 demonstrated pre-ICI IgG reactivity to a greater number of AutoAg than patients who did not develop irAEs (39 vs 33 p = 0.040). We observed post-treatment increase of IgM reactivities in subjects experiencing irAEs G ≥ 2 (29 vs 35, p = 0.021) and a decrease of IgG levels after steroids (38 vs 28, p = 0.009).

CONCLUSIONS

Overall, these results support the potential role of autoAb in irAEs etiology and evolution. A prospective study is ongoing to validate our findings (NCT04107311).

Immune checkpoint inhibitor-associated toxicity in advanced non-small cell lung cancer: An updated understanding of risk factors

Immune checkpoint inhibitors (ICIs), such as programmed death-1 (PD-1), programmed death-ligand 1 (PD-L1), cytotoxic T lymphocyte antigen 4 (CTLA-4) antibodies, etc, have revolutionized cancer treatment strategies, including non-small cell lung cancer (NSCLC). While these immunotherapy agents have achieved durable clinical benefits in a subset of NSCLC patients, they bring in a variety of immune-related adverse events (irAEs), which involve cardiac, pulmonary, gastrointestinal, endocrine and dermatologic system damage, ranging from mild to life-threatening. Thus, there is an urgent need to better understand the occurrence of irAEs and predict patients who are susceptible to those toxicities. Herein, we provide a comprehensive review of what is updated about the clinical manifestations, mechanisms, predictive biomarkers and management of ICI-associated toxicity in NSCLC. In addition, this review also provides perspective directions for future research of NSCLC-related irAEs.

Impairment of IgG Fc functions promotes tumor progression and suppresses NK cell antitumor actions

Natural killer (NK) cells mediate antibody dependent cytotoxic killing of cancer cells via cross-linking FcγR on NK cells with IgG-Fc. Studies have shown that the single-hinge cleaved IgGs (scIgGs) have dysfunctional Fc and failed engagement with FcγRs on immune cells. However, little is known about how scIgGs impact on antitumor immunity in the tumor microenvironment. In this study, we revealed a significant association of tumor scIgGs with tumor progression and poor outcomes of breast cancer patients (n = 547). Using multiple mouse tumor models, we demonstrated that tumor scIgGs reduced NK cell cytotoxic activities and resulted in aggressive tumor progression. We further showed that an anti-hinge specific monoclonal antibody (AHA) rescued the dysfunctional Fc in scIgGs by providing a functional Fc and restored NK cell cytotoxic activity. These findings point to a novel immunotherapeutic strategy to enhance Fc engagement with FcγRs for activation of anticancer immunity.

Circulating biomarkers of response to immunotherapy and immune-related adverse events

INTRODUCTION

Immune checkpoint blockade has revolutionized cancer treatment. However, response rates vary, and these treatments have a high rate of immune-related side effects, which can be limiting. Thus, tests to predict who will respond and who may experience side effects are of critical importance toward realizing the ultimate goal of precision oncology.

AREAS COVERED

We review several of the most recent advances in circulating biomarkers that have been reported to be useful in predicting response and immune-related adverse events (irAE) to checkpoint blockade immunotherapies (CBI). We focus on high-quality studies published within the last few years. We highlight significant findings, identify areas for improvement, and provide recommendations on how these biomarkers may be translated into clinical utility.

EXPERT OPINION

As newer immunotherapies are developed, there is a pressing need to identify circulating biomarkers that can help predict responses and side effects. Current studies are mostly small-scale and retrospective; there is a need for larger-scale and prospective studies to help validate several of the biomarkers detailed here. As oncology focuses more on precision-based approaches, it is likely that a combination of biomarkers, including circulating ones as detailed here, will have critical utility in guiding clinical decisions.

18F-FDG PET/CT Imaging of Immune Checkpoint Inhibitor-Related "Retroperitoneal Panniculitis"

ABSTRACT

A 71-year-old woman was operated on for undifferentiated lung adenocarcinoma. Four months after surgery, she developed bone and adrenal metastases. She underwent palliative radiation therapy of left scapula and right iliac bone. Thereafter, she started immune checkpoint inhibitor (ICI) therapy with anti-PD-1 antibodies achieving complete tumor response. Twenty months later, a follow-up 18F-FDG PET/CT confirmed tumor response and revealed high radiotracer accumulation in correspondence of retroperitoneal and subcutaneous fat opacities. The contiguous fasciae were mildly thickened. The temporal relation with ICI therapy together with tumor response and corticosteroids therapy effectiveness led to conclude for ICI-related adverse events.

Active and latent tuberculosis infections in patients treated with immune checkpoint inhibitors in a non-endemic tuberculosis area

BACKGROUND

Immune checkpoint inhibitors (ICIs) blocking inhibitory immune pathways (e.g., programmed cell death protein-1/-ligand1 [PD-1/PD-L1]) have revolutionized cancer therapy for numerous malignancies. There have been an increasing number of cases of active tuberculosis (TB) reported in association with ICI use, and recent data suggest alterations in immune responses in TB by ICI. The aim of this study was to characterize the frequency of latent tuberculosis infection (LTBI) and active TB in a large cohort of ICI-treated patients in a low TB incidence area.

METHODS

We conducted a retrospective review of all ICI-treated patients tested for TB between January, 1997 and August, 2018. Data extracted included patient demographics, TB risk factors, latent/active TB diagnosis and treatment, tumor type, ICI used, immunosuppressive medications, and mortality related to TB.

RESULTS

We identified 1844 ICI-treated patients, including 30 abnormal TB test results. Two patients were diagnosed with active TB, both prior to starting ICI therapy. One patient was treated for TB prior to starting ICI and the other patient was successfully treated concurrently. Seven patients were diagnosed with LTBI and none developed active TB. Twenty patients had indeterminate interferon gamma release assays (IGRA).

CONCLUSION

Despite recent reports of TB in patients taking ICI, we found no patients developing TB during ICI therapy in our large retrospective cohort of ICI-treated cancer patients in a non-endemic TB area. The high rate of indeterminate IGRA results suggests the need for prospective research with better diagnostics to quantify the actual risk of TB in this patient population.

Immune checkpoint inhibitors-related encephalitis in melanoma and non-melanoma cancer patients: a single center experience

Background

Treatment with immune checkpoint inhibitors (ICI) has greatly improved survival for patients with a number of malignant diseases in recent years. Neurological immune-related adverse events (n-irAE) of varying severity have been reported in the literature. We aimed to identify the incidence of n-irAE, focusing on immune-related encephalitis (IRE), in patients treated with ICI for multiple non-hematological malignancies in our institution.

Methods

All patients with histologically verified cancer that received treatment with ICI at the Sheba Medical Center between January 2017 and August 2019 were surveyed. Medical records for each patient were reviewed and information regarding n-irAE was recorded.

Results

In total, 1993 patients were included. Eleven cases of IRE were recorded, affecting 0.55% of patients overall, eight had non-melanoma cancer. Eight patients had made a full recovery.

Conclusions

IRE is a n-irAE more frequent than previously reported, particularly in non-melanoma patients. The diagnostic criteria and optimal treatment needs to be determined. ICI re-challenge after IRE can be considered for selected patients.

Circulating Biomarkers of Response and Toxicity of Immunotherapy in Advanced Non-Small Cell Lung Cancer (NSCLC): A Comprehensive Review

Simple Summary

Although immunotherapy has dramatically revolutionized non-small cell lung cancer (NSCLC) treatment, not all the patients will benefit from this innovative therapy. The identification of potential biomarkers able to predict efficacy and toxicity of immunotherapy represents an urgent need for tailored treatment regimens. Liquid biopsy is a minimally invasive and economical tool that could provide important information about patients’ selection and treatment monitoring. Currently, several blood biomarkers are under investigation (circulating immune and tumor cells, soluble immunological mediators, peripheral blood cells). Prospective clinical trials are needed to validate their use in clinical practice.

Abstract

Immune checkpoint inhibitors (ICIs) targeting the programmed cell death (PD)-1 protein and its ligand, PD-L1, and cytotoxic T-lymphocyte-associated antigen (CTLA)-4, have revolutionized the management of patients with advanced non-small cell lung cancer (NSCLC). Unfortunately, only a small portion of NSCLC patients respond to these agents. Furthermore, although immunotherapy is usually well tolerated, some patients experience severe immune-related adverse events (irAEs). Liquid biopsy is a non-invasive diagnostic procedure involving the isolation of circulating biomarkers, such as circulating tumor cells (CTC), cell-free DNA (cfDNA), and microRNAs (miRNAs). Thanks to recent advances in technologies, such as next-generation sequencing (NGS) and digital polymerase chain reaction (dPCR), liquid biopsy has become a useful tool to provide baseline information on the tumor, and to monitor response to treatments. This review highlights the potential role of liquid biomarkers in the selection of NSCLC patients who could respond to immunotherapy, and in the identification of patients who are most likely to experience irAEs, in order to guide improvements in care.

Integrative medicine in the era of cancer immunotherapy: Challenges and opportunities

Cancer immunotherapy has led to a new era of cancer treatment strategies, and transforming healthcare for cancer patients. Meanwhile, reports of immune-related adverse events have been increasing, greatly hindering the use of cancer immunotherapy. Traditional Chinese medicine (TCM), which has been widely used in Asian countries for thousands of years, is known to play a complementary role in the treatment of cancer. Taken in combined with conventional modern therapies, such as resection, ablation and radiotherapy, TCM exerts its main anti-cancer effects in two ways: health-strengthening (Fu-Zheng) and pathogen-eliminating (Qu-Xie). Theoretically, pathogen-eliminating TCM can promote the release of tumor-related antigens and should be able to increase the effect of immunotherapy, while health-strengthening TCM may have immune-enhancing mechanisms that overlap with immunotherapy. In the era of cancer immunotherapy, it is important to balance the use of TCM and immunotherapy, with the goal of enhancing immune efficacy and antagonizing immune toxicity. In this article, we discuss this issue by considering the mechanism of tumor immunotherapy, alongside the theoretical basis of TCM treatment of tumors, with the aim of bringing new insights to future research in this field.

Safety and efficacy of immune checkpoint inhibitors in non-small-cell lung cancer: focus on challenging populations

In recent years, immune-checkpoint inhibitors (ICIs) have represented one of the major breakthroughs in advanced non-small cell lung cancer treatment scenario. However, enrollment in registering clinical trials is usually restricted, since frail patients (i.e., elderly, individuals with poor performance status and/or active brain metastases), as well as patients with chronic infections or who take concurrent medications, such as steroids, are routinely excluded. Thus, safety and efficacy of ICIs for these subgroups have not been adequately assessed in clinical trials, although these populations often occur in clinical practice. We reviewed the available data regarding the use of ICIs in these 'special' populations, including a focus on the issues raised by the administration of immunotherapy in lung cancer patients infected with Sars-Cov-2.

[Predictable toxicities with futures immunotherapies or combinations]

Immunotherapy by immune check-points inhibitors (ICIs) recently improved many solid tumors survival data. ICIs target and inhibit down-regulation signals between T cells and tumor cells involved in carcinogenesis, in order to enhance anti-tumor immunity. With few years' hindsight of ICIs utilization in daily practice, we learned about their safety profile. By releasing the brakes of the host immune-system, ICIs exposure leads to on-target off-tumor immune related adverse events (IRAEs). Compared to standard chemotherapiy regimens, IRAEs remain rare, but sometimes serious and compromising treatment continuation, mostly despite objective tumor response. Several immunotherapy molecules are currently developed, with various mechanisms of action but always targeting the immune anti-tumor response. New drugs imply new safety profiles, especially since a lot of ongoing clinical trials are assessing combination of multiples drugs. Consequently, a good knowledge and management of these new toxicities will be essential to choose the new therapeutic schedules in many tumor types. Indeed, despite the actual poor prognosis of concerned tumor types, the progressive outcomes improvement implies long-term exposure to treatments. Safety and quality of life under treatment will become key endpoints for therapeutic decision.

How to Monitor Cardiac Complications of Immune Checkpoint Inhibitor Therapy

Immune-checkpoint inhibitors (ICIs) represent a successful paradigm in the treatment of cancer. ICIs elicit an immune response directed against cancer cells, by targeting the so-called immune checkpoints, key regulators of the immune system that when stimulated can dampen the immune response to an immunologic stimulus. Such response, however, is not entirely tumor-specific and may result in immune-related adverse events (irAEs), involving a number of organs and systems. Cardiovascular (CV) irAEs are rare, although potentially severe. In particular, several cases of ICI-related myocarditis with life-threatening course have been reported: the possibility of fulminant cases, thus, requires a high level of awareness among both oncologists and cardiologists. Aggressive work-up and management of symptomatic patients taking ICIs is fundamental for early recognition and initiation of specific immunosuppressive therapies. Notably, myocarditis occurs within few weeks from ICIs initiation, offering opportunity for a targeted screening. Troponin testing is the cornerstone of this screening, yet uncertainties remain regarding timing and candidates. Moreover, troponins positivity should be carefully interpreted. We herein review the main aspects of ICI-related myocarditis and suggest a practical approach. In particular, we focus on the opportunities that a baseline CV evaluation offers for subsequent management by collecting clinical and instrumental data, essential for the interpretation of troponin results, for differential diagnosis and for the formulation of a diagnostic and therapeutic workup.

Stakeholder perspectives on addressing adverse events from adjuvant cancer therapy: A qualitative study

BACKGROUND

With increasing survival rates, a growing population of patients with cancer have received or will receive adjuvant therapy to prevent cancer recurrences. Patients and caregivers will confront the complexities of balancing the preventative benefits of adjuvant therapy with possible near-term or long-term adverse events (AEs). Adjuvant treatment-related AEs (from minimal to severe) can impact therapeutic adherence, quality of life, emotional and physical health, and survival. However, to the authors' knowledge, limited information is available regarding how stakeholders use or desire to use adjuvant-related AE information to inform the care of patients with cancer.

METHODS

A qualitative, purposeful sampling approach was used to elicit stakeholder feedback via semistructured interviews (24 interviews). Drug development, drug regulatory, clinical, payer, and patient/patient advocacy stakeholders were questioned about the generation, dissemination, and use of adjuvant treatment-related AE information to inform the care of patients with cancer. Transcripts were coded independently by 2 senior health care researchers and reconciled to identify key themes.

RESULTS

All stakeholder groups in the current study identified needed improvements in each of the following 4 areas: 1) improving the accessibility and relevance of AE-related information; 2) better integrating and implementing available information regarding AEs for decisions; 3) connecting contemporary cultural and economic value systems to the generation and use of information regarding adjuvant treatment-related AEs; and 4) addressing a lack of alignment and ownership of stakeholder efforts to improve the use of AE information in the adjuvant setting.

CONCLUSIONS

Despite commonalities in the overall needs identified by the diverse stakeholders in the current study, broad systemic change has been stymied. The current study identified the lack of alignment and the absence of a central "owner" of these diffuse efforts as a previously unrecognized hurdle to realizing the desired systemic improvements. Future initiatives aimed at improving quality of life and outcomes for patients receiving adjuvant therapy through the improved use of AE information must address this challenge through innovative collectives and novel leadership strategies.

Myocarditis in Cynomolgus Monkeys Following Treatment with Immune Checkpoint Inhibitors

PURPOSE

Immune checkpoint inhibitors (ICI) targeting PD1, PDL1, or CTLA4 are associated with immune-related adverse events (irAE) in multiple organ systems including myocarditis. The pathogenesis and early diagnostic markers for ICI-induced myocarditis are poorly understood, and there is currently a lack of laboratory animal model to enhance our understanding. We aimed to develop such a model using cynomolgus monkeys.

EXPERIMENTAL DESIGN

Chinese-origin cynomolgus monkeys were dosed intravenously with vehicle or nivolumab 20 mg/kg plus ipilimumab 15 mg/kg once weekly and euthanized on day 29.

RESULTS

Multiple organ toxicities were observed in cynomolgus monkeys, and were characterized by loose feces, lymphadenopathy, and mononuclear cell infiltrations of varying severity in heart, colon, kidneys, liver, salivary glands, and endocrine organs. Increased proliferation of CD4⁺ and CD8⁺ T lymphocytes as well as an increase in activated T cells and central memory T cells in the blood, spleen, and lymph nodes, were observed. Transcriptomic analysis suggested increased migration and activation of T cells and increased phagocytosis and antigen presentation in the heart. Mononuclear cell infiltration in myocardium was comprised primarily of T cells, with lower numbers of macrophages and occasional B cells, and was associated with minimal cardiomyocyte degeneration as well as increases in cardiac troponin-I and NT-pro-BNP. Morphologically, cardiac lesions in our monkey model are similar to the reported ICI myocarditis in humans.

CONCLUSIONS

We have developed a monkey model characterized by multiple organ toxicities including myocarditis. This model may provide insight into the immune mechanisms and facilitate biomarker identification for ICI-associated irAEs.

The Interleukin-17 Family of Cytokines in Breast Cancer

Breast cancer (BC) is the most common cancer in women worldwide and remains a major cause of mortality with an expected 137,000 death this year in Europe. Standard management of metastatic BC comprises hormonotherapy, chemotherapy, and targeted therapies. Cyclin dependent kinase (CDK) and mammalian target of rapamycin (mTOR) inhibitors have recently proved their efficiency in hormonal receptor expressing BC. Checkpoint proteins inhibition is being evaluated in phase 3 studies. Since inflammation is constantly present in cancers, research teams have focused their attention on the interleukin-17 (IL-17) family of proinflammatory cytokines. Preclinical experiments have reported both pro and antitumor effects depending on the conditions. In the present article, we review the accumulating evidences about the roles of IL-17 in BC and discuss whether this family of cytokines could be a new target in anticancer treatments.

Serial Troponin for Early Detection of Nivolumab Cardiotoxicity in Advanced Non-Small Cell Lung Cancer Patients

BACKGROUND

Rare cases of severe myocarditis are reported during treatment with nivolumab. Troponin, a biomarker of cardiac damage, is a key component of the diagnostic workup of many cardiac disorders, including myocarditis. This study investigates the role of troponin to assess cardiac involvement during nivolumab therapy for non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

We evaluated 59 NSCLC patients, analyzing serum samples collected within a translational research study. Troponin above the upper normal limit (0.046 ng/mL) was defined as Tn+, whereas normal but detectable troponin (0.015-0.045) was defined as Tn^det. Troponin alterations were interpreted on the grounds of the following elements: peak values and time curve, cardiac comorbidities, signs and symptoms coincident to troponin elevation, ECG, echocardiography, and disease progression.

RESULTS

No patient had cardiovascular events. Among 362 available blood samples, Tn+ (max 0.317 ng/mL) was found in 13 determinations belonging to 6 patients. Seven other patients had isolated Tn^det. In five patients, Tn+ was attributed to cardiac comorbidities, disease progression, or worsening clinical status. One patient without cardiac history and in good clinical condition had a sustained troponin increase-soon after the start of therapy-and after careful evaluation of all relevant elements, it was interpreted as a marker of nivolumab-related subclinical myocarditis.

CONCLUSION

Tn+ may occur in NSCLC patients treated with nivolumab, but in most cases it does not indicate nivolumab cardiotoxicity. In some cases, however, a careful interpretation of troponin alteration, especially at the beginning of therapy, enables identification of subclinical myocarditis, thus allowing early cardiac treatment.

IMPLICATIONS FOR PRACTICE

Myocarditis is a rare but serious adverse event of immune checkpoint blockade with nivolumab, which needs to be recognized as soon as possible. This article suggests that troponin, a user-friendly biomarker of myocardial cytotoxicity, might be useful for early detection of immune-mediated myocarditis. However, because troponin abnormalities might also be related to a number of conditions capable of causing myocardial oxygen demand-supply mismatch, a careful cardiac assessment should be performed in non-small cell lung cancer patients in order to properly interpret any troponin increase. According to the available evidence, monitoring troponin during the first weeks of treatment can be considered reasonable.

Fatal Necrotizing Encephalopathy after Treatment with Nivolumab for Squamous Non-Small Cell Lung Cancer: Case Report and Review of the Literature

Immune checkpoint inhibitors are antibodies, which enhance cellular and humoral immune responses and are approved for the treatment of various tumors. Immune-related adverse events (irAE) involving different organs and systems are, however, among the side-effects. Recent reports of severe persistent neurological deficits and even fatal cases underpin the need for better understanding of the exact pathomechanisms of central nervous system (CNS) toxicity. To our knowledge, we report the first biopsy-proven case of fatal necrotizing encephalopathy after treatment with nivolumab. Nivolumab targets the immune-check point inhibitor programmed cell death-1 and was used for squamous non-small cell lung cancer. Partly reversible neurologic and psychiatric symptoms and unremarkable brain magnetic resonance imaging (MRI) were observed after the first course. Neurological symptoms progressed and recurrent seizures developed after the second course. Brain MRI disclosed multiple edematous and confluent supra- and infratentorial lesions, partly with contrast-enhancement. We excluded autoimmune and paraneoplastic causes and performed ancillary investigations to rule out common and opportunistic infections. Eventually, postmortem histopathological analysis of the brain revealed a necrotizing process, which contrasts previous cases reporting parenchymal immune cell infiltration or demyelination. Appropriate diagnostic pathways and treatment algorithms need to be implemented for the work-up of CNS toxicity and irAEs related to immune checkpoint inhibitor treatment.

Potential cardiac risk of immune-checkpoint blockade as anticancer treatment: What we know, what we do not know, and what we can do to prevent adverse effects

Cancer immunotherapy has become a well-established treatment option for some cancers after the development of a family of drugs targeting the so-called immune checkpoints, such as CTLA4 and PD-1 with PD-L1. These co-receptors/ligands inhibit the activation of T-cell, thus preventing an excessive inflammatory response. Tumors exploit these pathways to induce immune tolerance to themselves. Thus, the main effect of checkpoint-blocking drugs is to awake an immune response primarily directed against cancer cells. Nonetheless, as the immune response elicited by these drugs is not completely tumor-specific, their use may actually cause several adverse effects, including adverse cardiovascular effects. In this review, we will discuss the principles and potentiality of immunotherapy for cancer treatment, the experimental and clinical data on the role of CTLA4 and PD-1 with PD-L1 as immune-checkpoints in the cancer environment and in the cardiovascular system, and strategies aimed at preventing possible cardiovascular adverse effects of immune-checkpoint blockers.