First-in-human phase 1 study of the anti-TIGIT antibody vibostolimab as monotherapy or with pembrolizumab for advanced solid tumors, including non-small cell lung cancer

Quantitative multiplexed imaging technologies for single-cell analysis to assess predictive markers for immunotherapy in thoracic immuno-oncology: promises and challenges

The past decade has witnessed a revolution in cancer treatment by the shift from conventional drugs (chemotherapies) towards targeted molecular therapies and immune-based therapies, in particular the immune-checkpoint inhibitors (ICIs). These immunotherapies selectively release the host immune system against the tumour and have shown unprecedented durable remission for patients with cancers that were thought incurable such as advanced non-small cell lung cancer (aNSCLC). The prediction of therapy response is based since the first anti-PD-1/PD-L1 molecules FDA and EMA approvals on the level of PD-L1 tumour cells expression evaluated by immunohistochemistry, and recently more or less on tumour mutation burden in the USA. However, not all aNSCLC patients benefit from immunotherapy equally, since only around 30% of them received ICIs and among them 30% have an initial response to these treatments. Conversely, a few aNSCLC patients could have an efficacy ICIs response despite low PD-L1 tumour cells expression. In this context, there is an urgent need to look for additional robust predictive markers for ICIs efficacy in thoracic oncology. Understanding of the mechanisms that enable cancer cells to adapt to and eventually overcome therapy and identifying such mechanisms can help circumvent resistance and improve treatment. However, more than a unique universal marker, the evaluation of several molecules in the tumour at the same time, particularly by using multiplex immunostaining is a promising open room to optimise the selection of patients who benefit from ICIs. Therefore, urgent further efforts are needed to optimise to individualise immunotherapy based on both patient-specific and tumour-specific characteristics. This review aims to rethink the role of multiplex immunostaining in immuno-thoracic oncology, with the current advantages and limitations in the near-daily practice use.

CD155 and its receptors in cancer immune escape and immunotherapy

In recent years, there have been multiple breakthroughs in cancer immunotherapy, with immune checkpoint inhibitors becoming the most promising treatment strategy. However, available drugs are not always effective. As an emerging immune checkpoint molecule, CD155 has become an important target for immunotherapy. This review describes the structure and function of CD155, its receptors TIGIT, CD96, and CD226, and summarizes that CD155 expressed by tumor cells can upregulate its expression through the DNA damage response pathway and Ras-Raf-MEK-ERK signaling pathway. This review also elaborates the mechanism of immune escape after binding CD155 to its receptors TIGIT, CD96, and CD226, and summarizes the current progress of immunotherapy research regarding CD155 and its receptors. Besides, it also discusses the future direction of checkpoint immunotherapy.

Development and evaluation of nanobody tracers for noninvasive nuclear imaging of the immune-checkpoint TIGIT

Introduction

T cell Ig and ITIM domain receptor (TIGIT) is a next-generation immune checkpoint predominantly expressed on activated T cells and NK cells, exhibiting an unfavorable prognostic association with various malignancies. Despite the emergence of multiple TIGIT-blocking agents entering clinical trials, only a fraction of patients responded positively to anti-TIGIT therapy. Consequently, an urgent demand arises for noninvasive techniques to quantify and monitor TIGIT expression, facilitating patient stratification and enhancing therapeutic outcomes. Small antigen binding moieties such as nanobodies, are promising candidates for such tracer development.

Methods

We generated a panel of anti-human or anti-mouse TIGIT nanobodies from immunized llamas. In addition, we designed a single-chain variable fragment derived from the clinically tested monoclonal antibody Vibostolimab targeting TIGIT, and assessed its performance alongside the nanobodies. In vitro characterization studies were performed, including binding ability and affinity to cell expressed or recombinant TIGIT. After Technetium-99m labeling, the nanobodies and the single-chain variable fragment were evaluated in vivo for their ability to detect TIGIT expression using SPECT/CT imaging, followed by ex vivo biodistribution analysis.

Results

Nine nanobodies were selected for binding to recombinant and cell expressed TIGIT with low sub-nanomolar affinities and are thermostable. A six-fold higher uptake in TIGIT-overexpressing tumor was demonstrated one hour post- injection with Technetium-99m labeled nanobodies compared to an irrelevant control nanobody. Though the single-chain variable fragment exhibited superior binding to TIGIT-expressing peripheral blood mononuclear cells in vitro, its in vivo behavior yielded lower tumor-to-background ratios at one hour post- injection, indicating that nanobodies are better suited for in vivo imaging than the single-chain variable fragment. Despite the good affinity, high specificity and on-target uptake in mice in this setting, imaging of TIGIT expression on tumor- infiltrating lymphocytes within MC38 tumors remained elusive. This is likely due to the low expression levels of TIGIT in this model.

Discussion

The excellent affinity, high specificity and rapid on-target uptake in mice bearing TIGIT- overexpressing tumors showed the promising diagnostic potential of nanobodies to noninvasively image high TIGIT expression within the tumor. These findings hold promise for clinical translation to aid patient selection and improve therapy response.

Targeting LAG-3, TIM-3, and TIGIT for cancer immunotherapy

In one decade, immunotherapy based on immune checkpoint blockades (ICBs) has become a new pillar of cancer treatment following surgery, radiation, chemotherapy, and targeted therapies. However, not all cancer patients benefit from single or combination therapy with anti-CTLA-4 and anti-PD-1/PD-L1 monoclonal antibodies. Thus, an increasing number of immune checkpoint proteins (ICPs) have been screened and their effectiveness evaluated in preclinical and clinical trials. Lymphocyte activation gene-3 (LAG-3), T cell immunoglobulin and mucin-domain-containing-3 (TIM-3), and T cell immunoreceptor with immunoglobulin and tyrosine-based inhibitory motif (ITIM) domain (TIGIT) constitute the second wave of immunotherapy targets that show great promise for use in the treatment of solid tumors and leukemia. To promote the research and clinical application of ICBs directed at these targets, we summarize their discovery, immunotherapy mechanism, preclinical efficiency, and clinical trial results in this review.

New insights for gynecological cancer therapies: from molecular mechanisms and clinical evidence to future directions

Advanced and recurrent gynecological cancers lack effective treatment and have poor prognosis. Besides, there is urgent need for conservative treatment for fertility protection of young patients. Therefore, continued efforts are needed to further define underlying therapeutic targets and explore novel targeted strategies. Considerable advancements have been made with new insights into molecular mechanisms on cancer progression and breakthroughs in novel treatment strategies. Herein, we review the research that holds unique novelty and potential translational power to alter the current landscape of gynecological cancers and improve effective treatments. We outline the advent of promising therapies with their targeted biomolecules, including hormone receptor-targeted agents, inhibitors targeting epigenetic regulators, antiangiogenic agents, inhibitors of abnormal signaling pathways, poly (ADP-ribose) polymerase (PARP) inhibitors, agents targeting immune-suppressive regulators, and repurposed existing drugs. We particularly highlight clinical evidence and trace the ongoing clinical trials to investigate the translational value. Taken together, we conduct a thorough review on emerging agents for gynecological cancer treatment and further discuss their potential challenges and future opportunities.

Cancer immunotherapies: advances and bottlenecks

Immunotherapy has ushered in a new era in cancer treatment, and cancer immunotherapy continues to be rejuvenated. The clinical goal of cancer immunotherapy is to prime host immune system to provide passive or active immunity against malignant tumors. Tumor infiltrating leukocytes (TILs) play an immunomodulatory role in tumor microenvironment (TME) which is closely related to immune escape of tumor cells, thus influence tumor progress. Several cancer immunotherapies, include immune checkpoint inhibitors (ICIs), cancer vaccine, adoptive cell transfer (ACT), have shown great efficacy and promise. In this review, we will summarize the recent research advances in tumor immunotherapy, including the molecular mechanisms and clinical effects as well as limitations of immunotherapy.

CD155 and Its Receptors as Targets for Cancer Therapy

CD155, also known as the poliovirus receptor, is an adhesion molecule often overexpressed in tumors of different origins where it promotes cell migration and proliferation. In addition to this pro-tumorigenic function, CD155 plays an immunomodulatory role during tumor progression since it is a ligand for both the activating receptor DNAM-1 and the inhibitory receptor TIGIT, expressed on cytotoxic innate and adaptative lymphocytes. DNAM-1 is a well-recognized receptor involved in anti-tumor immune surveillance. However, in advanced tumor stages, TIGIT is up-regulated and acts as an immune checkpoint receptor, counterbalancing DNAM-1-mediated cancer cell clearance. Pre-clinical studies have proposed the direct targeting of CD155 on tumor cells as well as the enhancement of DNAM-1-mediated anti-tumor functions as promising therapeutic approaches. Moreover, immunotherapeutic use of anti-TIGIT blocking antibody alone or in combined therapy has already been included in clinical trials. The aim of this review is to summarize all these potential therapies, highlighting the still controversial role of CD155 during tumor progression.

TIGIT can inhibit T cell activation via ligation-induced nanoclusters, independent of CD226 co-stimulation

TIGIT is an inhibitory receptor expressed on lymphocytes and can inhibit T cells by preventing CD226 co-stimulation through interactions in cis or through competition of shared ligands. Whether TIGIT directly delivers cell-intrinsic inhibitory signals in T cells remains unclear. Here we show, by analysing lymphocytes from matched human tumour and peripheral blood samples, that TIGIT and CD226 co-expression is rare on tumour-infiltrating lymphocytes. Using super-resolution microscopy and other techniques, we demonstrate that ligation with CD155 causes TIGIT to reorganise into dense nanoclusters, which coalesce with T cell receptor (TCR)-rich clusters at immune synapses. Functionally, this reduces cytokine secretion in a manner dependent on TIGIT's intracellular ITT-like signalling motif. Thus, we provide evidence that TIGIT directly inhibits lymphocyte activation, acting independently of CD226, requiring intracellular signalling that is proximal to the TCR. Within the subset of tumours where TIGIT-expressing cells do not commonly co-express CD226, this will likely be the dominant mechanism of action.

Current immune therapeutic strategies in advanced or metastatic non-small cell lung cancer

ABSTRACT

Immune escape mechanisms in non-small cell lung cancer (NSCLC) can disrupt every step of the anti-cancer immune response. In recent years, an increased understanding of the specific mechanisms fueling immune escape has allowed for the development of numerous immunotherapeutic treatments that have been introduced into the clinical practice. The advent of immunotherapy has dramatically changed the current treatment landscape of advanced or metastatic NSCLC because of its durable efficacy and manageable toxicity. In this review, we will first present a brief overview of recent evidence on immune escape mechanisms in NSCLC. We will then discuss the current promising immunotherapeutic strategies in advanced or metastatic NSCLC tumors.

Pembrolizumab Plus Olaparib for Patients With Previously Treated and Biomarker-Unselected Metastatic Castration-Resistant Prostate Cancer: The Randomized, Open-Label, Phase III KEYLYNK-010 Trial

PURPOSE

There is an unmet need for therapeutic options that prolong survival for patients with heavily pretreated, metastatic castration-resistant prostate cancer (mCRPC). The phase III, open-label KEYLYNK-010 study evaluated pembrolizumab plus olaparib versus a next-generation hormonal agent (NHA) for biomarker-unselected, previously treated mCRPC.

METHODS

Eligible participants had mCRPC that progressed on or after abiraterone or enzalutamide (but not both) and docetaxel. Participants were randomly assigned (2:1) to pembrolizumab plus olaparib or NHA (abiraterone or enzalutamide). The dual primary end points were radiographic progression-free survival (rPFS) by blinded independent central review per Prostate Cancer Working Group-modified RECIST 1.1 and overall survival (OS). Time to first subsequent therapy (TFST) was a key secondary end point. Safety and objective response rate (ORR) were secondary end points.

RESULTS

Between May 30, 2019, and July 16, 2021, 529 participants were randomly assigned to pembrolizumab plus olaparib and 264 to NHA. At final rPFS analysis, median rPFS was 4.4 months (95% CI, 4.2 to 6.0) with pembrolizumab plus olaparib and 4.2 months (95% CI, 4.0 to 6.1) with NHA (hazard ratio [HR], 1.02 [95% CI, 0.82 to 1.25]; P = .55). At final OS analysis, median OS was 15.8 months (95% CI, 14.6 to 17.0) and 14.6 months (95% CI, 12.6 to 17.3), respectively (HR, 0.94 [95% CI, 0.77 to 1.14]; P = .26). At final TFST analysis, median TFST was 7.2 months (95% CI, 6.7 to 8.1) versus 5.7 months (95% CI, 5.0 to 7.1), respectively (HR, 0.86 [95% CI, 0.71 to 1.03]). ORR was higher with pembrolizumab plus olaparib versus NHA (16.8% v 5.9%). Grade ≥3 treatment-related adverse events occurred in 34.6% and 9.0% of participants, respectively.

CONCLUSION

Pembrolizumab plus olaparib did not significantly improve rPFS or OS versus NHA in participants with biomarker-unselected, heavily pretreated mCRPC. The study was stopped for futility. No new safety signals occurred.

Adjuvant therapy for stage II melanoma: the need for further studies

Immunotherapy with checkpoint inhibitors has revolutionised the outcomes for melanoma patients. In the metastatic setting, patients treated with nivolumab and ipilimumab have an expected 5-year survival of> 50%. For patients with resected high-risk stage III disease, adjuvant pembrolizumab, nivolumab or dabrafenib and trametinib are associated with a significant improvement in both relapse-free survival (RFS) and distant metastasis-free survival (DMFS). More recently neoadjuvant immunotherapy has shown very promising outcomes in patients with clinically detectable nodal disease and is likely to become a new standard of care. For stage IIB/C disease, two pivotal adjuvant trials of pembrolizumab and nivolumab have also reported a significant improvement in both RFS and DMFS. However, the absolute benefit is low and there are concerns about the risk of severe toxicities as well as long-term morbidity from endocrine toxicity. Ongoing registration phase III trials are currently evaluating newer immunotherapy combinations and the role of BRAF/MEK-directed targeted therapy for stage II melanoma. However, our ability to personalise therapy based on molecular risk stratification has lagged behind the development of novel immune therapies. There is a critical need to evaluate the use of tissue and blood-based biomarkers, to better select patients that will recur and avoid unnecessary treatment for the majority of patients cured by surgery alone.

The introduction of LAG-3 checkpoint blockade in melanoma: immunotherapy landscape beyond PD-1 and CTLA-4 inhibition

Despite major advances with immunotherapy and targeted therapy in the past decade, metastatic melanoma continues to be a deadly disease for close to half of all patients. Over the past decade, advancement in immune profiling and a deeper understanding of the immune tumor microenvironment (TME) have enabled the development of novel approaches targeting and a multitude of targets being investigated for the immunotherapy of melanoma. However, to date, immune checkpoint blockade has remained the most successful with programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1) and cytotoxic T-lymphocyte antigen-4 (CTLA-4) inhibitors, alone or in combination, yielding the most robust and durable clinical outcome in patients with metastatic melanoma. The highest rate of durable responses is achieved with the combination with PD-1 and CTLA-4 inhibition, and is effective in a variety of settings including brain metastases; however, it comes at the expense of a multitude of life-threatening toxicities occurring in up to 60% of patients. This has also established melanoma as the forefront of immuno-oncology (IO) drug development, and the search for novel checkpoints has been ongoing with multiple relevant targets including T-cell immunoglobulin and mucinodomain containing-3 (TIM-3), LAG-3, V-domain immunoglobulin suppressor T-cell activation (VISTA), T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain (TIGIT), among others. Lymphocyte activation gene-3 (LAG-3), which is a co-inhibitory receptor on T cells that suppress their activation, has revolutionized immunomodulation in melanoma. The 'game changing' results from the RELATIVITY-047 trial validated LAG-3 blockade as a relevant biological target and established it as the third clinically relevant immune checkpoint. Importantly, LAG-3 inhibition in combination with PD-1 inhibition offered impressive efficacy with modest increases in toxicity over single agent PD-1 inhibitor and has been U.S. Food and Drug Administration approved for the first-line therapy of patients with metastatic melanoma. The efficacy of this combination in patients with untreated brain or leptomeningeal metastases or with rare melanoma types, such as uveal melanoma, remains to be established. The challenge remains to elucidate specific mechanisms of response and resistance to LAG-3 blockade and to extend its benefits to other malignancies. Ongoing trials are studying the combination of LAG-3 antibodies with PD-1 inhibitors in multiple cancers and settings. The low toxicity of the combination may also allow for further layering of additional therapeutic approaches such as chemotherapy, oncolytic viruses, cellular therapies, and possibly novel cytokines, among others.

Radiation and immune checkpoint inhibitors in the treatment of oligometastatic non-small-cell lung cancer: a practical review of rationale, recent data, and research questions

The combined use of stereotactic ablative radiotherapy (SABR) and immune checkpoint inhibitors (ICIs) is an emerging treatment paradigm for oligometastatic non-small-cell lung cancer (NSCLC). Recent phase I and II trial data suggest that SABR to multiple metastases in addition to ICI use is safe and effective with promising progression-free survival and overall survival signals. There is great interest in capitalizing on combined immunomodulation from these two modalities for the treatment of oligometastatic NSCLC. Ongoing trials seek to validate the safety, efficacy, and preferred sequencing of SABR and ICI. This narrative review of the role of SABR when combined with ICI in oligometastatic NSCLC discusses the rationale for this bimodality treatment, summarizes recent clinical trial evidence, and proposes key principles of management based on the available evidence.

Double Guard Efficiency and Safety-Overcoming Resistance to Immunotherapy by Blocking or Stimulating Several Immune Checkpoints in Non-Small Cell Lung Cancer Patients

Immunotherapy is one of the leading systemic therapies in non-small cell cancer (NSCLC) patients, but it is not effective in an important proportion of them due to primary or secondary resistance mechanisms. Clinicians do not have the tools to predict immunotherapy resistance, and thus, many patients still fail initial treatment. One of the scientific concepts to avoid resistance and/or offer the patient effective salvage second-line treatment is the dual immunologic checkpoint blockade. We aimed to review published and available data on combination immunotherapy in terms of mechanisms, efficacy, and safety data on many different dual blockades. We discussed the potential of combined CTLA-4 (Cytotoxic T Lymphocyte Antigen 4), PD-1 (Programmed Death 1) or PD-L1, TIGIT, LAG-3, TIM-3, macrophage leukocyte immunoglobulin-like receptor B2 (LILRB2/ILT4), S15-mediated immune suppression (SIGLEC-15), CD137, ICOS, and OX40 inhibitors in NSCLC treatment.

Shining a LIGHT on myeloid cell targeted immunotherapy

Despite over a decade of clinical trials combining inhibition of emerging checkpoints with a PD-1/L1 inhibitor backbone, meaningful survival benefits have not been shown in PD-1/L1 inhibitor resistant or refractory solid tumours, particularly tumours dominated by a myelosuppressive microenvironment. Achieving durable anti-tumour immunity will therefore likely require combination of adaptive and innate immune stimulation, myeloid repolarisation, enhanced APC activation and antigen processing/presentation, lifting of the CD47/SIRPα (Cluster of Differentiation 47/signal regulatory protein alpha) 'do not eat me' signal, provision of an apoptotic 'pro-eat me' or 'find me' signal, and blockade of immune checkpoints. The importance of effectively targeting mLILRB2 and SIRPAyeloid cells to achieve improved response rates has recently been emphasised, given myeloid cells are abundant in the tumour microenvironment of most solid tumours. TNFSF14, or LIGHT, is a tumour necrosis superfamily ligand with a broad range of adaptive and innate immune activities, including (1) myeloid cell activation through Lymphotoxin Beta Receptor (LTβR), (2) T/NK (T cell and natural killer cell) induced anti-tumour immune activity through Herpes virus entry mediator (HVEM), (3) potentiation of proinflammatory cytokine/chemokine secretion through LTβR on tumour stromal cells, (4) direct induction of tumour cell apoptosis in vitro, and (5) the reorganisation of lymphatic tissue architecture, including within the tumour microenvironment (TME), by promoting high endothelial venule (HEV) formation and induction of tertiary lymphoid structures. LTBR (Lymphotoxin beta receptor) and HVEM rank highly amongst a range of costimulatory receptors in solid tumours, which raises interest in considering how LIGHT-mediated costimulation may be distinct from a growing list of immunotherapy targets which have failed to provide survival benefit as monotherapy or in combination with PD-1 inhibitors, particularly in the checkpoint acquired resistant setting.

Emerging agents for the treatment of advanced or metastatic NSCLC without actionable genomic alterations with progression on first-line therapy

INTRODUCTION

Lung cancer is the second most common cancer in the world and the leading cause of cancer-related mortality. Immune checkpoint inhibitors (ICIs), as monotherapy or in combination with platinum-based chemotherapy, have emerged as the standard of care first-line treatment option for patients with advanced non-small cell lung cancer (NSCLC) without actionable genomic alterations (AGAs). Despite significant improvements in patient outcomes with these regimens, primary or acquired resistance is common and most patients develop disease progression, resulting in poor survival.

AREAS COVERED

We review the current treatments commonly used for NSCLC without AGAs in the first-line and subsequent settings and describe the unmet needs for these patients in the second-line setting, including a lack of standard definitions for primary and required resistance, and few effective treatment options for patients who develop progression of their disease on first-line therapy. We describe key mechanisms of resistance to ICIs and emerging therapies that are being investigated for patients who develop progression on ICIs and platinum-based chemotherapy.

EXPERT OPINION

Emerging agents in development have a variety of different mechanisms of action and will likely change standard of care for second-line therapy and beyond for patients with NSCLC without AGAs in the future.

Self-delivery of TIGIT-blocking scFv enhances CAR-T immunotherapy in solid tumors

Chimeric antigen receptor T cell therapy has become an important immunotherapeutic tool for overcoming cancers. However, the efficacy of CAR-T cell therapy in solid tumors is relatively poor due to the complexity of the tumor microenvironment and inhibitory immune checkpoints. TIGIT on the surface of T cells acts as an immune checkpoint by binding to CD155 on the tumor cells' surface, thereby inhibiting tumor cell killing. Blocking TIGIT/CD155 interactions is a promising approach in cancer immunotherapy. In this study, we generated anti-MLSN CAR-T cells in combination with anti-α-TIGIT for solid tumors treatment. The anti-α-TIGIT effectively enhanced the efficacy of anti-MLSN CAR-T cells on the killing of target cells in vitro. In addition, we genetically engineered anti-MSLN CAR-T cells with the capacity to constitutively produce TIGIT-blocking single-chain variable fragments. Our study demonstrated that blocking TIGIT significantly promoted cytokine release to augment the tumor-killing effect of MT CAR-T cells. Moreover, the self-delivery of TIGIT-blocking scFvs enhanced the infiltration and activation of MT CAR-T cells in the tumor microenvironments to achieve better tumor regression in vivo. These results suggest that blocking TIGIT effectively enhances the anti-tumor effect of CAR-T cells and suggest a promising strategy of combining CAR-T with immune checkpoints blockade in the treatment of solid tumors.

Co-inhibition of TIGIT and PD-1/PD-L1 in Cancer Immunotherapy: Mechanisms and Clinical Trials

Over the past decade, immune checkpoint inhibitors (ICIs) have emerged as a revolutionary cancer treatment modality, offering long-lasting responses and survival benefits for a substantial number of cancer patients. However, the response rates to ICIs vary significantly among individuals and cancer types, with a notable proportion of patients exhibiting resistance or showing no response. Therefore, dual ICI combination therapy has been proposed as a potential strategy to address these challenges. One of the targets is TIGIT, an inhibitory receptor associated with T-cell exhaustion. TIGIT has diverse immunosuppressive effects on the cancer immunity cycle, including the inhibition of natural killer cell effector function, suppression of dendritic cell maturation, promotion of macrophage polarization to the M2 phenotype, and differentiation of T cells to regulatory T cells. Furthermore, TIGIT is linked with PD-1 expression, and it can synergize with PD-1/PD-L1 blockade to enhance tumor rejection. Preclinical studies have demonstrated the potential benefits of co-inhibition of TIGIT and PD-1/PD-L1 in enhancing anti-tumor immunity and improving treatment outcomes in several cancer types. Several clinical trials are underway to evaluate the safety and efficacy of TIGIT and PD-1/PD-L1 co-inhibition in various cancer types, and the results are awaited. This review provides an overview of the mechanisms of TIGIT and PD-1/PD-L1 co-inhibition in anti-tumor treatment, summarizes the latest clinical trials investigating this combination therapy, and discusses its prospects. Overall, co-inhibition of TIGIT and PD-1/PD-L1 represents a promising therapeutic approach for cancer treatment that has the potential to improve the outcomes of cancer patients treated with ICIs.

Next-Generation Approaches to Immuno-Oncology in GI Cancers

Immunotherapy has only had a modest impact on the treatment of advanced GI malignancies. Microsatellite-stable colorectal cancer and pancreatic adenocarcinoma, the most common GI tumors, have not benefited from treatment with standard immune checkpoint inhibitors. With this huge unmet need, multiple approaches are being tried to overcome barriers to better anticancer outcomes. This article reviews a number of novel approaches to immunotherapy for these tumors. These include the use of novel checkpoint inhibitors such as a modified anti-cytotoxic T lymphocyte-associated antigen-4 antibody and antibodies to lymphocyte-activation gene 3, T cell immunoreceptor with immunoglobulin and ITIM domains, T-cell immunoglobulin-3, CD47, and combinations with signal transduction inhibitors. We will discuss other trials that aim to elicit an antitumor T-cell response using cancer vaccines and oncolytic viruses. Finally, we review attempts to replicate in GI cancers the frequent and durable responses seen in hematologic malignancies with immune cell therapies.

Novel Immunotherapeutics: Perspectives on Checkpoints, Bispecifics, and Vaccines in Development

Over the past decade, the advent of molecular techniques and deeper understanding of the tumor microenvironment (TME) have enabled the development of a multitude of immunotherapy targets and approaches. Despite the revolutionary advancement in immunotherapy, treatment resistance remains a challenge leading to decreased response rate in a significant proportion of patients. As such, there has recently been an evolving focus to enhance efficacy, durability, and toxicity profiles of immunotherapy. Although immune checkpoint inhibitors have revolutionized cancer treatment with many already-approved antibodies and several others in the pipeline, bispecific antibodies build on their success in an attempt to deliver an even more potent immune response against tumor cells. On the other hand, vaccines comprise the oldest and most versatile form of immunotherapy. Peptide and nucleic acid vaccines are relatively simple to manufacture compared with oncolytic virus-based vaccines, whereas the dendritic cell vaccines are the most complex, requiring autologous cell culture. Nevertheless, a crucial question in the development of cancer vaccines is the choice of antigen whereby shared and patient-private antigen approaches are currently being pursued. There is hope that cancer vaccines will join the repertoire of successful novel immunotherapeutics in the market. Better insights into the impact of immunotherapy on effector T cells and other immune cell populations in the TME shall be a major priority across the immune-oncology discipline and can help identify predictive biomarkers to evaluate response to treatment and identify patients who would most likely benefit from immunotherapy.

Cocktail hepatocarcinoma therapy by a super-assembled nano-pill targeting XPO1 and ATR synergistically

Intensive cancer treatment with drug combination is widely exploited in the clinic but suffers from inconsistent pharmacokinetics among different therapeutic agents. To overcome it, the emerging nanomedicine offers an unparalleled opportunity for encapsulating multiple drugs in a nano-carrier. Herein, a two-step super-assembled strategy was performed to unify the pharmacokinetics of a peptide and a small molecular compound. In this proof-of-concept study, the bioinformatics analysis firstly revealed the potential synergies towards hepatoma therapy for the associative inhibition of exportin 1 (XPO1) and ataxia telangiectasia mutated-Rad3-related (ATR), and then a super-assembled nano-pill (gold nano drug carrier loaded AZD6738 and 97-110 amino acids of apoptin (AP) (AA@G)) was constructed through camouflaging AZD6738 (ATR small-molecule inhibitor)-binding human serum albumin onto the AP-Au supramolecular nanoparticle. As expected, both in vitro and in vivo experiment results verified that the AA@G possessed extraordinary biocompatibility and enhanced therapeutic effect through inducing cell cycle arrest, promoting DNA damage and inhibiting DNA repair of hepatoma cell. This work not only provides a co-delivery strategy for intensive liver cancer treatment with the clinical translational potential, but develops a common approach to unify the pharmacokinetics of peptide and small-molecular compounds, thereby extending the scope of drugs for developing the advanced combination therapy.

TIGIT: An emerging immune checkpoint target for immunotherapy in autoimmune disease and cancer

Immune checkpoints (ICs), also referred to as co-inhibitory receptors (IRs), are essential for regulating immune cell function to maintain tolerance and prevent autoimmunity. IRs, such as programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), have been shown to possess immunoregulatory properties that are relevant to various autoimmune diseases and cancers. Tumors are characterized by suppressive microenvironments with elevated levels of IRs on tumor-infiltrating lymphocytes (TILs). Therefore, IR blockade has shown great potential in cancer therapy and has even been approved for clinical use. However, other IRs, including cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain (TIGIT), may also represent promising targets for anti-tumor therapy. The increasing importance of IRs in autoimmune diseases has become apparent. In mouse models, TIGIT pathway blockade or TIGIT deficiency has been linked to T cell overactivation and proliferation, exacerbation of inflammation, and increased susceptibility to autoimmune disorders. On the other hand, TIGIT activation has been shown to alleviate autoimmune disorders in murine models. Given these findings, we examine the effects of TIGIT and its potential as a therapeutic target for both autoimmune diseases and cancers. It is clear that TIGIT represents an emerging and exciting target for immunotherapy in these contexts.

Studying TIGIT activity against tumors through the generation of knockout mice

The use of antibodies to block inhibitory receptors, primarily anti-PD1 and CTLA4 (known as checkpoint therapy) revolutionized cancer treatment. However, despite these successes, the majority of cancer patients do not respond to the checkpoint treatment, emphasizing the need for development of additional therapies, which are based on other inhibitory receptors. Human TIGIT is an inhibitory receptor expressed by Natural Killer (NK) and T cells and is mainly known to interact with PVR, Nectin-2, Nectin-3, and Nectin-4. Whether mouse TIGIT interacts with all of these ligands is still unclear. Additionally, the in vivo function of TIGIT against tumors is not completely understood. Here, we demonstrate that mouse TIGIT interacts with and is inhibited by mPVR only. Using CRISPR-Cas9 technology, we generated TIGIT-deficient mice and demonstrated that NK cell cytotoxicity and degranulation against two tumor types were lower in WT mice when compared to the TIGIT KO mice. Moreover, in vivo tumor progression was slower in TIGIT KO than in WT mice. Taken together, our data established that mTIGIT has only one ligand, PVR, and that in the absence of TIGIT tumors are killed better both in vitro and in vivo.

TIGIT-based immunotherapeutics in lung cancer

In this review, we explore the biology of the TIGIT checkpoint and its potential as a therapeutic target in lung cancer. We briefly review a highly selected set of clinical trials that have reported or are currently recruiting in non-small cell and small cell lung cancer, a disease transformed by the advent of PD-1/PD-L1 checkpoint blockade immunotherapy. We explore the murine data underlying TIGIT blockade and further explore the reliance of effective anti-TIGIT therapy on DNAM-1(CD226)-positive activated effector CD8+ T cells. The synergism with anti-PD-1 therapy is also explored. Future directions in the realm of overcoming resistance to checkpoint blockade and extending the repertoire of other checkpoints are also briefly explored.

Study on the Effect of EZH2 Inhibitor Combined with TIGIT Monoclonal Antibody against Multiple Myeloma Cells

EZH2, a member of the polycomb repressive complex 2, induces trimethylation of the downstream gene at the histone three lysine 27 (H3K27me3) position to inhibit tumor cell proliferation. Here, we showed that the apoptosis rate and apoptotic protein expression increased after EZH2 inhibition, whereas key molecules of the NF-κB signaling pathway and the downstream target genes were inhibited. Additionally, the expression of CD155, a TIGIT high-affinity ligand in multiple myeloma (MM) cells, was decreased by the mTOR signaling pathway. Furthermore, the combination of EZH2 inhibitor and TIGIT monoclonal antibody blockade enhanced the anti-tumor effect of natural killer cells. In summary, the EZH2 inhibitor not only plays an anti-tumor role as an epigenetic drug, but also enhances the anti-tumor effect of the TIGIT monoclonal antibody by affecting the TIGIT-CD155 axis between NK cells and MM cells, thus providing new ideas and theoretical basis for the treatment of MM patients.

Emerging trends and focus on immune checkpoint inhibitors for non-small cell lung cancer treatment: visualization and bibliometric analysis

Introduction: Lung cancer is the leading cause of cancer-related deaths worldwide, and non-small cell lung carcinoma (NSCLC) accounts for approximately 80% of all cases. Immune checkpoint inhibitors (ICIs) are widely used to treat NSCLC owing to their remarkable efficacy. In this study, we analyzed the scientific collaboration network, defined the hotspots of research on the use of ICIs for NSCLC treatment, analyzed its evolution over the past few years, and forecasted the field's future development using bibliometric analysis and a graphical study. Methods: Research articles and reviews regarding ICIs for NSCLC were retrieved and obtained from the Web of Science Core Collection on 26 September 2022. CtieSpace and VOSviewer were thereafter used to conduct the bibliometric and knowledge-map analysis. Results: We included 8,149 articles for this literature analysis. Our analysis showed that the USA had the highest number of publications and citations. We also noted that research trends in this field have changed drastically over the past 20 years, from the early development of ICIs, such as CTLA-4 inhibitors, to the development of recent ones, such as PD-1 and PD-L1 blockers. Further, the focus of research in this field has also gradually shifted from mechanisms to treatment effects and adverse events, suggesting that the field is maturing. Clinical applications are also being explored, including studies on how to enhance efficacy, reduce adverse effects, and expand to other specific cancer types. Conclusion: To the best of our knowledge, this is the first study to construct a comprehensive knowledge map on ICIs for NSCLC. It can help researchers rapidly grasp the status and focus of current research in this area, offer direction, and serve as a reference for conducting similar studies.

TIGIT in Lung Cancer: Potential Theranostic Implications

TIGIT (T cell immunoreceptor with Ig and ITIM domains) is a co-inhibitory receptor expressed on various immune cells, including T cells, NK cells, and dendritic cells. TIGIT interacts with different ligands, such as CD155 and CD112, which are highly expressed on cancer cells, leading to the suppression of immune responses. Recent studies have highlighted the importance of TIGIT in regulating immune cell function in the tumor microenvironment and its role as a potential therapeutic target, especially in the field of lung cancer. However, the role of TIGIT in cancer development and progression remains controversial, particularly regarding the relevance of its expression both in the tumor microenvironment and on tumor cells, with prognostic and predictive implications that remain to date essentially undisclosed. Here, we provide a review of the recent advances in TIGIT-blockade in lung cancer, and also insights on TIGIT relevance as an immunohistochemical biomarker and its possible theranostic implications.

Immune-checkpoint inhibitor resistance in cancer treatment: Current progress and future directions

Cancer treatment has been advanced with the advent of immune checkpoint inhibitors (ICIs) exemplified by anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), anti-programmed cell death protein 1 (PD-1) and programmed cell death ligand 1 (PD-L1) drugs. Patients have reaped substantial benefit from ICIs in many cancer types. However, few patients benefit from ICIs whereas the vast majority undergoing these treatments do not obtain survival benefit. Even for patients with initial responses, they may encounter drug resistance in their subsequent treatments, which limits the efficacy of ICIs. Therefore, a deepening understanding of drug resistance is critically important for the explorations of approaches to reverse drug resistance and to boost ICI efficacy. In the present review, different mechanisms of ICI resistance have been summarized according to the tumor intrinsic, tumor microenvironment (TME) and host classifications. We further elaborated corresponding strategies to battle against such resistance accordingly, which include targeting defects in antigen presentation, dysregulated interferon-γ (IFN-γ) signaling, neoantigen depletion, upregulation of other T cell checkpoints as well as immunosuppression and exclusion mediated by TME. Moreover, regarding the host, several additional approaches that interfere with diet and gut microbiome have also been described in reversing ICI resistance. Additionally, we provide an overall glimpse into the ongoing clinical trials that utilize these mechanisms to overcome ICI resistance. Finally, we summarize the challenges and opportunities that needs to be addressed in the investigation of ICI resistance mechanisms, with the aim to benefit more patients with cancer.

Identification of a novel peptide targeting TIGIT to evaluate immunomodulation of 125I seed brachytherapy in HCC by near-infrared fluorescence

Introduction

Hepatocellular carcinoma (HCC) has very poor prognosis due to its immunosuppressive properties. An effective measure to regulate tumor immunity is brachytherapy, which uses 125I seeds planted into tumor. T cell immune receptors with immunoglobulin and ITIM domains (TIGIT) is highly expressed in HCC. The TIGIT-targeted probe is expected to be an effective tool for indicating immunomodulation of 125I seed brachytherapy in HCC. In this study, We constructed a novel peptide targeting TIGIT to evaluate the immune regulation of 125I seed brachytherapy for HCC by near-infrared fluorescence (NIRF).

Methods

Expression of TIGIT by immunofluorescence (IF) and flow cytometry (FCM) in different part and different differentiated human liver cancer tissues was verified. An optical fluorescence probe (Po-12) containing a NIRF dye and TIGIT peptide was synthesized for evaluating the modulatory effect of 125I seed brachytherapy. Lymphocytes uptake by Po-12 were detected by FCM and confocal microscopy. The distribution and accumulation of Po-12 in vivo were explored by NIRF imaging in subcutaneous and orthotopic tumors. IHC and IF staining were used to verify the expression of TIGIT in the tumors.

Results

TIGIT was highly expressed in HCC and increased with tumor differentiation. The dye-labeled peptide (Po-12) retained a stable binding affinity for the TIGIT protein in vitro. Accumulation of fluorescence intensity (FI) increased with time extended in subcutaneous H22 tumors, and the optimal point is 1 h. TIGIT was highly expressed on lymphocytes infiltrated in tumors and could be suppressed by 125I seed brachytherapy. Accumulation of Po-12-Cy5 was increased in tumor-bearing groups while declined in 125I radiation group.

[Combination strategies for checkpoint inhibition: Current practices and perspectives]

T-cell checkpoint blockade therapies have revolutionized treatment protocols and prognosis in patients with cancer. Pointed out by the success of PD-1 (programmed cell death-1) plus CTLA-4 (cytotoxic-T-lymphocyte associated antigen 4) blockade in patients with melanoma, the perspective of new synergistic immunotherapy combinations seems to be an important opportunity to improve outcomes for patients. In this article, we first focus on immunotherapy combinations that have shown their efficiency and that are currently approved in solid tumors. Then, we present a summary of emerging targets with reported pre-clinical efficacy and currently evaluated through ongoing clinical trials and other immunomodulatory molecules in the tumor microenvironment.

Combining radiotherapy and NK cell-based therapies: The time has come

Natural killer (NK) cells are innate lymphoid cells that play an essential role in the anti-tumor response through immunosurveillance, multiple mechanisms of cytotoxicity and the synthesis of cytokines modulating the immune tumor microenvironment (TME). After the dramatic advances in immunotherapy targeting T cells including the success of checkpoint inhibitors or autologous chimeric antigen receptor (CAR) expressing T cells in clinical practice, NK cells have gained growing interest for the development of new therapies. Although NK cells have shown promising responses in leukemia patients, the effects of NK-targeted therapies are currently limited in the treatment of solid tumors. Thus, radiotherapy could provide a valuable solution to improve treatments targeting NK cells. Indeed, ionizing radiations represent a powerful immuno-modulator that can either induce a pro-inflammatory and anti-tumor TME, or conversely lead to immunosuppression of effector immune cells in favor of tumor growth and therapeutic escape, depending on how it is delivered and tumor models. However, the effects of ionizing radiation on NK cells are only partially understood. Therefore, we review the effects of radiotherapy on the NK cell-mediated anti-tumor response, and propose potential strategies to reinvigorate NK cells by combining radiotherapy with NK cell-targeted therapies.

Bintrafusp Alfa, a Bifunctional Fusion Protein Targeting TGF-β and PD-L1, in Patients With Non-Small Cell Lung Cancer Resistant or Refractory to Immune Checkpoint Inhibitors

BACKGROUND

Bintrafusp alfa is a first-in-class bifunctional fusion protein composed of the extracellular domain of transforming growth factor beta receptor II (a TGF-β "trap") fused to a human immunoglobulin G1 monoclonal antibody blocking programmed cell death 1 ligand 1 (PD-L1). We report the efficacy and safety in patients with non-small cell lung cancer (NSCLC) that progressed following anti-PD-(L)1 therapy.

MATERIALS AND METHODS

In this expansion cohort of NCT02517398-a global, open-label, phase I trial-adults with advanced NSCLC that progressed following chemotherapy and was primary refractory or had acquired resistance to anti-PD-(L)1 treatment received intravenous bintrafusp alfa 1200 mg every 2 weeks until confirmed progression, unacceptable toxicity, or trial withdrawal. The primary endpoint was best overall response (by Response Evaluation Criteria in Solid Tumors version 1.1 adjudicated by independent review committee); secondary endpoints included safety.

RESULTS

Eighty-three eligible patients (62 [74.7%] treated with ≥3 prior therapies) received bintrafusp alfa. Four patients (3 primary refractory, 1 acquired resistant) had confirmed partial responses (objective response rate, 4.8%; 95% CI, 1.3%-11.9%), and 9 had stable disease. Tumor cell PD-L1 expression was not associated with response. Nineteen patients (22.9%) experienced grade ≥3 treatment-related adverse events, most commonly asthenia (3 [3.6%]) and fatigue, eczema, and pruritus (2 each [2.4%]). One patient had grade 4 amylase increased. One patient died during treatment for pneumonia before initiation of bintrafusp alfa.

CONCLUSION

Although the primary endpoint was not met, bintrafusp alfa showed some clinical activity and a manageable safety profile in patients with heavily pretreated NSCLC, including prior anti-PD-(L)1 therapy. Tumor responses occurred irrespective of whether disease was primary refractory or had acquired resistance to prior anti-PD-(L)1 therapy.

Anti-TIGIT therapies for solid tumors: a systematic review

Programmed death-ligand 1[PD-(L)1], cytotoxic T-lymphocyte associated protein 4 (CTLA-4), and lymphocyte-activation gene 3 (LAG-3) inhibitors are recent breakthroughs in cancer treatment, however not all patients benefit from it. Thus new therapies are under investigation, such as anti-TIGIT [anti-T-cell immunoreceptor with immunoglobulin (Ig) and immunoreceptor tyrosine-based inhibitory motif domains] antibodies. TIGIT is an immune checkpoint inhibiting lymphocyte T cells by several mechanisms. In vitro models showed its inhibition could restore antitumor response. Furthermore, its association with anti-PD-(L)1 therapies could synergistically improve survival. We carried out a review of the clinical trial about TIGIT referenced in the PubMed database, finding three published clinical trials on anti-TIGIT therapies. Vibostolimab was evaluated in a phase I alone or in combination with pembrolizumab. The combination had an objective response rate of 26% in patients with a non-small-cell lung cancer (NSCLC) naïve of anti-programmed cell death protein 1 (anti-PD-1). Etigilimab was tested in a phase I alone or in combination with nivolumab, but the study was stopped due to business reasons. In the phase II CITYSCAPE trial, tiragolumab demonstrated higher objective response rate and progression-free survival in combination with atezolizumab than atezolizumab alone in advanced PD-L1-high NSCLC. The ClinicalTrials.gov database references 70 trials of anti-TIGIT in patients with cancer, 47 of them with ongoing recruitment. Only seven were phase III, including five about patients with NSCLC, mostly with combination therapy. Data from phase I-II trials highlighted that targeting TIGIT represents a safe therapeutic approach, with an acceptable toxicity profile maintained when adding anti-PD-(L)1 antibodies. Frequent adverse events were pruritus, rash, and fatigue. Grade 3-4 adverse events were reported in nearly one in three patients. Anti-TIGIT antibodies are under development as a novel immunotherapy approach. A promising research area includes the combination with anti-PD-1 therapies in advanced NSCLCs.

GITR and TIGIT immunotherapy provokes divergent multi-cellular responses in the tumor microenvironment of gastrointestinal cancers

Understanding the cellular mechanisms of novel immunotherapy agents in the human tumor microenvironment (TME) is critical to their clinical success. We examined GITR and TIGIT immunotherapy in gastric and colon cancer patients using ex vivo slice tumor slice cultures derived from cancer surgical resections. This primary culture system maintains the original TME in a near-native state. We applied paired single-cell RNA and TCR sequencing to identify cell type specific transcriptional reprogramming. The GITR agonist was limited to increasing effector gene expression only in cytotoxic CD8 T cells. The TIGIT antagonist increased TCR signaling and activated both cytotoxic and dysfunctional CD8 T cells, including clonotypes indicative of potential tumor antigen reactivity. The TIGIT antagonist also activated T follicular helper-like cells and dendritic cells, and reduced markers of immunosuppression in regulatory T cells. Overall, we identified cellular mechanisms of action of these two immunotherapy targets in the patients' TME.

At the crossroads of immunotherapy for oncogene-addicted subsets of NSCLC

Non-small-cell lung cancer (NSCLC) has become a paradigm of precision medicine, with the discovery of numerous disease subtypes defined by specific oncogenic driver mutations leading to the development of a range of molecularly targeted therapies. Over the past decade, rapid progress has also been made in the development of immune-checkpoint inhibitors (ICIs), especially antagonistic antibodies targeting the PD-L1-PD-1 axis, for the treatment of NSCLC. Although many of the major oncogenic drivers of NSCLC are associated with intrinsic resistance to ICIs, patients with certain oncogene-driven subtypes of the disease that are highly responsive to specific targeted therapies might also derive benefit from immunotherapy. However, the development of effective immunotherapy approaches for oncogene-addicted NSCLC has been challenged by a lack of predictive biomarkers for patient selection and limited knowledge of how ICIs and oncogene-directed targeted therapies should be combined. Therefore, whether ICIs alone or with chemotherapy or even in combination with molecularly targeted agents would offer comparable benefit in the context of selected oncogenic driver alterations to that observed in the general unselected NSCLC population remains an open question. In this Review, we discuss the effects of oncogenic driver mutations on the efficacy of ICIs and the immune tumour microenvironment as well as the potential vulnerabilities that could be exploited to overcome the challenges of immunotherapy for oncogene-addicted NSCLC.

Immunotherapy-based combinations in metastatic NSCLC

Immuno-oncology has revolutionized the treatment of metastatic non-small cell lung cancer (mNSCLC) since the approval of immunotherapy by the U.S. FDA in 2015. Despite the advancements, outcomes for patients have room for further improvement. Combination therapies have shown promise in overcoming resistance and improving outcomes. This review focuses on current immunotherapy-based combination approaches, reported and ongoing trials, as well as novel combination strategies, challenges, and future directions for mNSCLC treatment. We summarize approaches in combination with chemotherapy, novel immune checkpoints, tyrosine kinase inhibitors and other strategies including vaccines, and radiation therapy. The promise of biomarker-driven studies to understand resistance and design multi-arm platform trials that evaluate novel therapies is becoming of increasing relevance with the ultimate goal of administering precision immunotherapy by identifying the right dose of the right combination for the right patient at the right time.

Mechanisms of drug resistance to immune checkpoint inhibitors in non-small cell lung cancer

Immune checkpoint inhibitors (ICIs) in the form of anti-CTLA-4 and anti-PD-1/PD-L1 have become the frontier of cancer treatment and successfully prolonged the survival of patients with advanced non-small cell lung cancer (NSCLC). But the efficacy varies among different patient population, and many patients succumb to disease progression after an initial response to ICIs. Current research highlights the heterogeneity of resistance mechanisms and the critical role of tumor microenvironment (TME) in ICIs resistance. In this review, we discussed the mechanisms of ICIs resistance in NSCLC, and proposed strategies to overcome resistance.

High Co-Expression of PDCD1/TIGIT/CD47/KIR3DL2 in Bone Marrow Is Associated with Poor Prognosis for Patients with Myelodysplastic Syndrome

Cellular immune disorder is a common characteristic of myelodysplastic syndrome (MDS). Abnormal natural killer (NK) cell function has been reported in MDS patients, and this is closely related to disease progression and poor prognosis. However, little is known about the association between the abnormal immune checkpoint (IC) that results in abnormal immune NK cell function and the prognosis of MDS. In this study, RNA-sequencing data from 80 patients in the GSE114922 dataset and bone marrow (BM) samples from 46 patients with MDS in our clinical center were used for overall survival (OS) analysis and validation. We found that the NK cell-related IC genes PDCD1, TIGIT, CD47, and KIR3DL2 had higher expression and correlated with poor OS for MDS patients. High expression of PDCD1 or TIGIT was significantly associated with poor OS for MDS patients younger than 60 years of age. Moreover, co-expression of PDCD1 and TIGIT had the greatest contribution to OS prediction. Interestingly, PDCD1, TIGIT, CD47, and KIR3DL2 and risk stratification based on the Revised International Prognostic Scoring System were used to construct a nomogram model, which could visually predict the 1-, 2-, and 3-year survival rates of MDS patients. In summary, high expression of IC receptors in the BM of MDS patients was associated with poor OS. The co-expression patterns of PDCD1, TIGIT, CD47, and KIR3DL2 might provide novel insights into designing combined targeted therapies for MDS.

Mocetinostat in Combination With Durvalumab for Patients With Advanced NSCLC: Results From a Phase I/II Study

BACKGROUND

Histone deacetylase (HDAC) inhibitors have potential to augment the effectiveness of immune checkpoint inhibitors and overcome treatment resistance. This dose-escalation/expansion study (NCT02805660) investigated mocetinostat (class I/IV HDAC inhibitor) plus durvalumab in patients with advanced non-small cell lung cancer (NSCLC) across cohorts defined by tumor programmed death-ligand 1 (PD-L1) expression and prior experience with anti-programmed cell death protein-1 (anti-PD-1) or anti-PD-L1 regimens.

PATIENTS AND METHODS

Sequential cohorts of patients with solid tumors received mocetinostat (starting dose: 50 mg TIW) plus durvalumab at a standard dose (1500 mg Q4W) to determine the recommended phase II dose (RP2D: phase I primary endpoint), based on the observed safety profile. RP2D was administered to patients with advanced NSCLC across 4 cohorts grouped by tumor PD-L1 expression (none or low/high) and prior experience with anti-PD-L1 /anti-PD-1 agents (naïve, clinical benefit: yes/no). The phase II primary endpoint was objective response rate (ORR, RECIST v1.1).

RESULTS

Eighty-three patients were enrolled (phase I [n = 20], phase II [n = 63]). RP2D was mocetinostat 70 mg TIW plus durvalumab. ORR was 11.5% across the phase II cohorts, and responses were durable (median 329 days). Clinical activity was observed in NSCLC patients with disease refractory to prior checkpoint inhibitor treatment: ORR 23.1%. Across all patients, fatigue (41%), nausea (40%), and diarrhea (31%) were the most frequent treatment-related adverse events.

CONCLUSION

Mocetinostat 70 mg TIW plus durvalumab at the standard dose was generally well tolerated. Clinical activity was observed in patients with NSCLC unresponsive to prior anti-PD-(L)1 therapy.

Therapeutic strategies for non-small cell lung cancer: Experimental models and emerging biomarkers to monitor drug efficacies

While new targeted therapies have considerably changed the treatment and prognosis of non-small cell lung cancer (NSCLC), they are frequently unsuccessful due to primary or acquired resistances. Chemoresistance is a complex process that combines cancer cell intrinsic mechanisms including molecular and genetic abnormalities, aberrant interactions within the tumor microenvironment, and the pharmacokinetic characteristics of each molecule. From a pharmacological point of view, two levers could improve the response to treatment: (i) developing tools to predict the response to chemo- and targeted therapies and (ii) gaining a better understanding of the influence of the tumor microenvironment. Both personalized medicine approaches require the identification of relevant experimental models and biomarkers to understand and fight against chemoresistance mechanisms. After describing the main therapies in NSCLC, the scope of this review will be to identify and to discuss relevant in vitro and ex vivo experimental models that are able to mimic tumors. In addition, the interests of these models in the predictive responses to proposed therapies will be discussed. Finally, this review will evaluate the involvement of novel secreted biomarkers such as tumor DNA or micro RNA in predicting responses to anti-tumor therapies.

Pembrolizumab for previously treated, microsatellite instability–high/mismatch repair–deficient advanced colorectal cancer: final analysis of KEYNOTE-164

BACKGROUND

Pembrolizumab demonstrated durable clinical benefit and manageable safety in previously treated advanced or metastatic microsatellite instability-high (MSI-H)/mismatch repair deficient (dMMR) colorectal cancer (CRC) in the phase 2 KEYNOTE-164 study. Results from the final analysis are presented.

METHODS

Eligible patients had unresectable or metastatic MSI-H/dMMR CRC and ≥2 prior systemic therapies (cohort A) or ≥1 prior systemic therapy (cohort B). Patients received pembrolizumab 200 mg intravenously every 3 weeks for ≤35 cycles. The primary end-point was objective response rate (ORR) assessed per Response Evaluation Criteria in Solid Tumors, version 1.1 by blinded independent central review. Secondary end-points included duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety and tolerability.

RESULTS

Sixty-one patients in cohort A and 63 patients in cohort B were enroled; median follow-up was 62.2 months and 54.4 months, respectively. ORR was 32.8% (95% CI, 21.3%-46.0%) in cohort A and 34.9% (95% CI, 23.3%-48.0%) in cohort B. Median DOR was not reached (NR) in either cohort. Median PFS was 2.3 months (95% CI, 2.1-8.1) in cohort A and 4.1 months (95% CI, 2.1-18.9) in cohort B. Median OS was 31.4 months (95% CI, 21.4-58.0) in cohort A and 47.0 months (95% CI, 19.2-NR) in cohort B. No new safety signals were observed. Nine patients who initially responded experienced disease progression off therapy and received second-course pembrolizumab. Six patients (66.7%) completed an additional 17 cycles of pembrolizumab, and 2 patients achieved a partial response.

CONCLUSIONS

Pembrolizumab continued to show durable antitumor activity, prolonged OS, and manageable safety in patients with previously treated MSI-H/dMMR CRC.

CLINICAL TRIAL REGISTRY INFORMATION

ClinicalTrials.gov, NCT02460198.

Reactivation of natural killer cells with monoclonal antibodies in the microenvironment of malignant neoplasms

Natural killer cells are critical players in the antitumor immune response due to their ability to destroy target cells through cytotoxic activity and other means. However, this response is inhibited in the tumor microenvironment, where a crippling hypoxic environment and several inhibitory molecules bind to NK cells to trigger an anergic state. Inhibitory receptors such as PD-1, NK2GA, KIR, TIGIT, and LAG-3 have been associated with inhibition of NK cells in multiple cancer types. Binding to these receptors leads to loss of cytotoxicity, lower proliferation and metabolic rates, and even apoptosis. While these receptors are important for avoiding auto-immunity, in a pathological setting like malignant neoplasms they are disadvantageous for the individual's immune system to combat cancer cells. The use of monoclonal antibodies to block these receptors contributes to cancer therapy by preventing the inhibition of NK cells. In this review, the impact of NK cell inhibition and activation on cancer therapy was summarized and an overview of the blockade of inhibitory pathways by monoclonal antibodies was provided.

Therapeutic Potential of Targeting Transforming Growth Factor-beta (TGF-β) and Programmed Death-ligand 1 (PD-L1) in Pancreatic Cancer

Pancreatic cancer (PC) is one the most lethal malignancies worldwide affecting around half a million individuals each year. The treatment of PC is relatively difficult due to the difficulty in making an early diagnosis. Transforming growth factor-beta (TGF-β) is a multifunctional factor acting as both a tumor promoter in early cancer stages and a tumor suppressor in advanced disease. Programmed death-ligand 1 (PD-L1) is a ligand of programmed death-1 (PD-1), an immune checkpoint receptor, allowing tumor cells to avoid elimination by immune cells. Recently, targeting the TGF-β signaling and PD-L1 pathways has emerged as a strategy for cancer therapy. In this review, we have summarized the current knowledge regarding these pathways and their contribution to tumor development with a focus on PC. Moreover, we have reviewed the role of TGF-β and PD-L1 blockade in the treatment of various cancer types, including PC, and discussed the clinical trials evaluating TGF-β and PD-L1 antagonists in PC patients.

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.

Advances in immune checkpoint inhibitors induced-cardiotoxicity

Immune checkpoint inhibitors (ICIs) are approved as the first-line drug for treating many cancers and has shown significant survival benefits; however, it also causes immune-related adverse events (irAEs) while activating the immune system, involving multiple organs. Among them, cardiovascular immune-related adverse events (CV-irAE) are rare, but common causes of death in ICIs treated cancer patients, which manifest as myocardial, pericardial, vascular and other cardiovascular toxicities. Therefore, it is important that irAEs, especially CV-irAE should be carefully recognized and monitored during the whole ICIs treatment because early detection and treatment of CV-irAE can significantly reduce the mortality of such patients. Consequently, it is urgent to fully understand the mechanism and management strategies of CV-irAE. The effects of ICIs are multifaceted and the exact mechanism of CV-irAE is still elusive. Generally, T cells identify tumor cell antigens as well as antigen in cardiomyocytes that are the same as or homologous to those on tumor cells, thus causing myocardial damage. In addition, ICIs promote formation of cardiac troponin I (cTnI) that induces cardiac dysfunction and myocardial dilatation; moreover, ICIs also increase the production of cytokines, which promote infiltration of inflammation-linked molecules into off-target tissues. Currently, the management and treatment of cardiovascular toxicity are largely dependent on glucocorticoids, more strategies for prevention and treatment of CV-irAE, such as predictive markers are being explored. This review discusses risk factors, potential pathophysiological mechanisms, clinical manifestations, and management and treatment of CV-irAE, guiding the development of more effective prevention, treatment and management strategies in the future.

TIGIT: A promising target to overcome the barrier of immunotherapy in hematological malignancies

Immune evasion through up-regulating checkpoint inhibitory receptors on T cells plays an essential role in tumor initiation and progression. Therefore, immunotherapy, including immune checkpoint inhibitor targeting programmed cell death protein 1 (PD-1) and chimeric antigen receptor T cell (CAR-T) therapy, has become a promising strategy for hematological malignancies. T cell immunoreceptor with immunoglobulin and ITIM domain (TIGIT) is a novel checkpoint inhibitory receptor expressed on immune cells, including cytotoxic T cells, regulatory T cells, and NK cells. TIGIT participates in immune regulation via binding to its ligand CD155. Blockage of TIGIT has provided evidence of considerable efficacy in solid tumors in preclinical research and clinical trials, especially when combined with PD-1 inhibition. However, the mechanism and function of TIGIT in hematological malignancies have not been comprehensively studied. In this review, we focus on the role of TIGIT in hematological malignancies and discuss therapeutic strategies targeting TIGIT, which may provide a promising immunotherapy target for hematological malignancies.

TIGIT Expression on Intratumoral Lymphocytes Correlates with Improved Prognosis in Oral Squamous Cell Carcinoma

(1) Background: T-cell immunoglobulin and ITIM domain (TIGIT) is a potential immunotherapeutic target in a variety of malignant entities, and antibody-based treatments are currently under investigation in clinical trials. While promising results were observed in patients with lung cancer, the role of TIGIT in oral squamous cell carcinoma (OSCC) as a biomarker as well as a therapeutic target remains elusive. Therefore, we evaluated the role of TIGIT as a prognostic factor in OSCC. (2) Methods: Here, we describe the results of a retrospective tissue microarray (TMA) OSCC cohort. Using immunohistochemistry, TIGIT expression was correlated with overall and recurrence-free survival (OAS and RFS, respectively). Additionally, in silico analysis was performed based on the TCGA Head and Neck Squamous Cell Carcinoma (HNSCC) cohort in order to correlate patients' survival with TIGIT and CD274 (encoding for PD-L1) gene expression levels. (3) Results: Database analysis revealed a beneficial outcome in OAS for tumor patients with high intraepithelial CD3-TIGIT-expression (n = 327). Hereby, OAS was 53.9 months vs. 30.1 months for patients with lower TIGIT gene expression levels (p = 0.033). In our retrospective OSCC-TMA cohort, elevated TIGIT levels on CD3+ cells correlated significantly with improved OAS (p = 0.025) as well as distant RFS (p = 0.026). (4) Conclusions: This study introduces TIGIT as a novel prognostic factor in OSCC, indicating the improved outcome of OSCC patients relative to their increased TIGIT expression. TIGIT might provide therapeutic implications for future immunotherapy in advanced-stage OSCC patients.

Current and novel therapeutic strategies for optimizing immunotherapy outcomes in advanced non-small cell lung cancer

During the past decade, immunotherapy has dramatically improved the outcomes of patients with non-small cell lung cancer (NSCLC). The development of specific antibodies against the programmed death (PD1) receptor and its ligand PD-L1 (programmed death ligand-1) has demonstrated substantial efficacy in advanced NSCLC either in the first or in the second line. However, the success of immune checkpoint inhibitors (ICIs) as monotherapy did not reach all patients and long-term responders still represent a small subset of cases. Under these circumstances, different strategies have been and are being tested to optimize clinical outcomes. Here, we reviewed the current evidence and the more promising perspectives of ICI combination approaches, such as the addition of chemotherapy, antiangiogenic agents, other co-inhibitory or co-stimulatory checkpoints, and targeted therapies.

Combination TIGIT/PD-1 blockade enhances the efficacy of neoantigen vaccines in a model of pancreatic cancer

Background

Cancer neoantigens are important targets of cancer immunotherapy and neoantigen vaccines are currently in development in pancreatic ductal adenocarcinoma (PDAC) and other cancer types. Immune regulatory mechanisms in pancreatic cancer may limit the efficacy of neoantigen vaccines. Targeting immune checkpoint signaling pathways in PDAC may improve the efficacy of neoantigen vaccines.

Methods

We used KPC4580P, an established model of PDAC, to test whether neoantigen vaccines can generate therapeutic efficacy against PDAC. We focused on two immunogenic neoantigens associated with genetic alterations in the CAR12 and CDK12 genes. We tested a neoantigen vaccine comprised of two 20-mer synthetic long peptides and poly IC, a Toll-like receptor (TLR) agonist. We investigated the ability of neoantigen vaccine alone, or in combination with PD-1 and TIGIT signaling blockade to impact tumor growth. We also assessed the impact of TIGIT signaling on T cell responses in human PDAC.

Results

Neoantigen vaccines induce neoantigen-specific T cell responses in tumor-bearing mice and slow KPC4580P tumor growth. However, KPC4580P tumors express high levels of PD-L1 and the TIGIT ligand, CD155. A subset of neoantigen-specific T cells in KPC4580P tumors are dysfunctional, and express high levels of TIGIT. PD-1 and TIGIT signaling blockade in vivo reverses T cell dysfunction and enhances neoantigen vaccine-induced T cell responses and tumor regression. In human translational studies, TIGIT signaling blockade in vitro enhances neoantigen-specific T cell function following vaccination.

Conclusions

Taken together, preclinical and human translational studies support testing neoantigen vaccines in combination with therapies targeting the PD-1 and TIGIT signaling pathways in patients with PDAC.

Mechanisms of primary and acquired resistance to immune checkpoint inhibitors in advanced non-small cell lung cancer: A multiplex immunohistochemistry-based single-cell analysis

OBJECTIVE

Immune checkpoint inhibitors (ICIs) have become a key therapeutic modality for advanced non-small cell lung cancer (NSCLC), but most patients experience primary or acquired resistance to these drugs. We here explored the mechanisms underlying both types of ICI resistance by analysis of the tumor immune microenvironment (TME).

MATERIALS AND METHODS

Four patients who experienced a long-term response to ICI treatment (progression-free survival [PFS] of ≥12 months) followed by disease progression, after which a rebiopsy was immediately performed (cohort-A), as well as four patients who experienced early tumor progression during ICI treatment (PFS of <9 weeks, cohort-B) were enrolled in this retrospective study. The pretreatment TME was evaluated by 16- or 17-color multiplex immunohistochemistry (mIHC)-based spatial profiling at the single-cell level for both cohorts. In cohort-A, changes in the TME after disease progression during ICI treatment were also investigated by mIHC analysis and transcriptomic analysis.

RESULTS

Pretreatment tumor tissue from cohort-B manifested poor infiltration of tumor-reactive CD8⁺ T cells characterized by CD39 and CD103 expression or by programmed cell death-1 expression, implicating insufficient recognition of tumor cells by CD8⁺ T cells as a mechanism of primary ICI resistance. Analysis of the paired tumor specimens from cohort-A revealed various changes in the TME associated with acquired ICI resistance, including substantial infiltration of myeloid-derived suppressor cells and M2-type tumor-associated macrophages without a marked decline in the number of tumor-reactive CD8⁺ T cells; a decrease in the number of tumor-reactive CD8⁺ T cells; and an apparent decrease in neoantigen presentation by tumor cells.

CONCLUSION

The presence of intratumoral tumor-reactive CD8⁺ T cells may be a prerequisite for a long-term response to ICI treatment in advanced NSCLC, but it is not sufficient for cancer cell eradication. Various TME profiles are associated with acquired ICI resistance, suggesting that patient-specific strategies to overcome such resistance may be necessary.