Eftilagimod alpha, a soluble lymphocyte activation gene-3 (LAG-3) protein plus pembrolizumab in patients with metastatic melanoma

Beyond Immune Checkpoint Inhibitors: Emerging Targets in Melanoma Therapy

PURPOSE OF REVIEW

This review provides a comprehensive update on recent advancements in melanoma treatment by highlighting promising therapeutics with an aim to increase awareness of novel interventions currently in development.

RECENT FINDINGS

Over the last decade there has been considerable expansion of the previously available treatment options for patients with melanoma. In particular, novel immunotherapeutics have been developed to expand on the clinical advancements brought by BRAF targeting and immune checkpoint inhibitors. Despite the success of checkpoint inhibitors there remains an unmet need for patients that do not respond to treatment. This review delves into the latest advancements in novel checkpoint inhibitors, cytokines, oncolytic viruses, vaccines, bispecific antibodies, and adoptive cell therapy. Preclinical experiments and early-stage clinical trials studies have demonstrated promising results for these therapies, many of which have moved into pivotal, phase 3 studies.

Development of pharmacological immunoregulatory anti-cancer therapeutics: current mechanistic studies and clinical opportunities

Immunotherapy represented by anti-PD-(L)1 and anti-CTLA-4 inhibitors has revolutionized cancer treatment, but challenges related to resistance and toxicity still remain. Due to the advancement of immuno-oncology, an increasing number of novel immunoregulatory targets and mechanisms are being revealed, with relevant therapies promising to improve clinical immunotherapy in the foreseeable future. Therefore, comprehending the larger picture is important. In this review, we analyze and summarize the current landscape of preclinical and translational mechanistic research, drug development, and clinical trials that brought about next-generation pharmacological immunoregulatory anti-cancer agents and drug candidates beyond classical immune checkpoint inhibitors. Along with further clarification of cancer immunobiology and advances in antibody engineering, agents targeting additional inhibitory immune checkpoints, including LAG-3, TIM-3, TIGIT, CD47, and B7 family members are becoming an important part of cancer immunotherapy research and discovery, as are structurally and functionally optimized novel anti-PD-(L)1 and anti-CTLA-4 agents and agonists of co-stimulatory molecules of T cells. Exemplified by bispecific T cell engagers, newly emerging bi-specific and multi-specific antibodies targeting immunoregulatory molecules can provide considerable clinical benefits. Next-generation agents also include immune epigenetic drugs and cytokine-based therapeutics. Cell therapies, cancer vaccines, and oncolytic viruses are not covered in this review. This comprehensive review might aid in further development and the fastest possible clinical adoption of effective immuno-oncology modalities for the benefit of patients.

Current State of Melanoma Therapy and Next Steps: Battling Therapeutic Resistance

Melanoma is the most aggressive and deadly form of skin cancer due to its high propensity to metastasize to distant organs. Significant progress has been made in the last few decades in melanoma therapeutics, most notably in targeted therapy and immunotherapy. These approaches have greatly improved treatment response outcomes; however, they remain limited in their abilities to hinder disease progression due, in part, to the onset of acquired resistance. In parallel, intrinsic resistance to therapy remains an issue to be resolved. In this review, we summarize currently available therapeutic options for melanoma treatment and focus on possible mechanisms that drive therapeutic resistance. A better understanding of therapy resistance will provide improved rational strategies to overcome these obstacles.

Soluble lymphocyte activation gene-3 (sLAG3) and CD4/CD8 ratio dynamics as predictive biomarkers in patients undergoing immune checkpoint blockade for solid malignancies

BACKGROUND

The search for biomarkers to identify suitable candidates for immune checkpoint inhibitor (ICI) therapy remains ongoing. We evaluate how soluble levels of the next generation immune checkpoint Lymphocyte Activation Gene-3 (sLAG-3) and its association with circulating T lymphocyte subsets could pose as a novel biomarker to predict outcome to ICI therapy.

METHODS

Circulating levels of sLAG3 were analyzed using multiplex immunoassay in n = 84 patients undergoing ICI therapy for advanced solid cancer, accompanied by flow cytometry analyses of peripheral blood mononuclear cells (PBMCs).

RESULTS

Uni- and multivariate analysis shows that patients with higher sLAG3 concentrations before ICI therapy had a significantly impaired progression-free (PFS) and overall survival (OS) (HRPFS: 1.005 [95%CI: 1.000-1.009], p = 0.039; HROS: 1.006 [95%CI: 1.001-1.011], p = 0.015). The CD4/CD8 cell ratio and its dynamics during therapy were strong predictors of PFS and OS with patients with a decreasing ratio between baseline and after 1-2 cycles having an improved median OS compared to patients with increasing values (p = 0.012, HR: 3.32). An immunological score combining sLAG3 and the CD4/CD8 ratio showed the highest predictive potential (HROS: 10.3).

CONCLUSION

Pending prospective validation, sLAG3 and correlating circulating T-cell subsets can be used as a non-invasive predictive marker to predict outcome to ICI therapy to help identifying ideal ICI candidates in the future.

Rheumatic adverse events of immune checkpoint inhibitors in cancer immunotherapy

INTRODUCTION

The advent of immune checkpoint inhibitors (ICIs) in cancer treatment has marked a transformative era, albeit tempered by immune-related adverse events (irAEs), including those impacting the musculoskeletal system. The lack of precise epidemiologic data on rheumatic irAEs is attributed to factors such as potential underrecognition, underreporting in clinical trials, and the tendency to overlook manifestations without immediate life-threatening implications, further complicating the determination of accurate incidence rates, while the complete understanding of the mechanisms driving rheumatic irAEs remains elusive.

AREAS COVERED

This literature review comprehensively examines rheumatic irAEs in cancer patients undergoing ICI therapy, encompassing epidemiology, risk factors, mechanisms, clinical manifestations, and current management guidance for prevalent conditions such as inflammatory arthritis, polymyalgia rheumatica, and myositis. Less frequent rheumatic and musculoskeletal irAEs are also explored, alongside insights into ongoing clinical trials testing therapeutic and preventive strategies for irAEs. A thorough literature search on Medline and the National Cancer Institute Clinical Trials Database was conducted up to October 2023 to compile relevant information.

EXPERT OPINION

In light of the evolving landscape of cancer immunotherapy, there is a compelling need for prospective longitudinal studies to enhance understanding and inform clinical management strategies for rheumatic irAEs.

Nano-enhanced immunotherapy: Targeting the immunosuppressive tumor microenvironment

The tumor microenvironment (TME), which is mostly composed of tumor cells, immune cells, signaling molecules, stromal tissue, and the vascular system, is an integrated system that is conducive to the formation of tumors. TME heterogeneity makes the response to immunotherapy different in different tumors, such as "immune-cold" and "immune-hot" tumors. Tumor-associated macrophages, myeloid-derived suppressor cells, and regulatory T cells are the major suppressive immune cells and their different phenotypes interact and influence cancer cells by secreting different signaling factors, thus playing a key role in the formation of the TME as well as in the initiation, growth, and metastasis of cancer cells. Nanotechnology development has facilitated overcoming the obstacles that limit the further development of conventional immunotherapy, such as toxic side effects and lack of targeting. In this review, we focus on the role of three major suppressive immune cells in the TME as well as in tumor development, clinical trials of different drugs targeting immune cells, and different attempts to combine drugs with nanomaterials. The aim is to reveal the relationship between immunotherapy, immunosuppressive TME and nanomedicine, thus laying the foundation for further development of immunotherapy.

Novel immune checkpoint targets: A promising therapy for cancer treatments

The immune system frequently comprises immunological checkpoints. They serve as a barrier to keep the immune system from overreacting and damaging cells that are robust. Immune checkpoint inhibitors (ICIs) are utilized in immunotherapy to prevent the synergy of partner proteins of checkpoint proteins with auxiliary proteins. Moreover, the T cells may target malignant cells since the "off" signal cannot be conveyed. ICIs, which are mostly composed of monoclonal antibodies (mAbs) against cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and anti- programmed death-1/programmed ligand 1 (anti-PD-1/PD-L1), might transform the context of cancer therapy. Further, more patients continued to exhibit adaptive resistance, even though several ICIs demonstrated convincing therapeutic benefits in selective tumor types. Immune checkpoint therapy's overall effectiveness is still lacking at this time. A popular area of study involves investigating additional immune checkpoint molecules. Recent research has found a number of fresh immune checkpoint targets, including NKG2A ligands, TIGIT, B7-H6 ligands, Galectin 3, TIM3, and so on. These targets have been focus of the study, and recent investigational approaches have shown encouraging outcomes. In this review article, we covered the development and present level understanding of these recently identified immune checkpoint molecules, its effectiveness and limitations.

Prognostic significance of Lymphocyte-activation gene 3 (LAG3) in patients with solid tumors: a systematic review, meta-analysis and pan-cancer analysis

BACKGROUND

Lymphocyte-activation gene 3 (LAG3) is a recently discovered immune checkpoint molecule that has been linked to immunosuppression and the advancement of cancer in different types of solid tumors. This study aimed to evaluate the prognostic importance of LAG3 and its role in the immune system within solid tumors.

METHODS

Extensive literature searches were conducted using the Pubmed, EMBASE, and Cochrane Library databases to identify relevant studies exploring the effect of LAG3 on survival outcomes. Pooled hazard ratios (HRs) with its 95% confidence intervals (CIs) were calculated to evaluate the prognostic values of LAG3. Afterwards, subgroup analysis and sensitivity analysis were conducted. Pan-cancer analysis investigated the possible relationships between LAG3 expression and genetic alterations, RNA methylation modification-related genes, genomic instability, immune checkpoint genes, and infiltration of immune cells.

RESULTS

A total of 43 studies with 7,118 patients were included in this analysis. Higher expression of LAG3 was associated with worse overall survival (HR = 1.10, 95% CI 1.01-1.19, P = 0.023), but not disease-free survival (HR = 1.41, 95% CI 0.96-2.07, P = 0.078), progression-free survival (HR = 1.12, 95% CI 0.90-1.39, P = 0.317) or recurrence-free survival (HR = 0.98, 95% CI 0.81-1.19, P = 0.871). Subgroup analysis showed that LAG3 might play different prognostic roles in different solid tumors. LAG3 expression was positively associated with immune cell infiltration and immune checkpoint genes in all of the cancers included. LAG3 expression was also found to be associated with microsatellite instability (MSI), copy number variation (CNV), simple nucleoside variation (SNV), tumor mutation burden (TMB), and neoantigen in various types of cancers.

CONCLUSIONS

Elevated expression of LAG3 is linked to poorer prognosis among patients diagnosed with solid cancers. LAG3 might play varying prognostic roles in different types of solid tumors. Given its substantial involvement in cancer immunity and tumorigenesis, LAG3 has garnered attention as a promising prognostic biomarker and a potential target for immunotherapy.

Advancement of anti-LAG-3 in cancer therapy

Immune checkpoint inhibitors have effectively transformed the treatment of many cancers, particularly those highly devastating malignancies. With their widespread popularity, the drawbacks of immune checkpoint inhibitors are also recognized, such as drug resistance and immune-related systematic side effects. Thus, it never stops investigating novel immune checkpoint inhibitors. Lymphocyte Activation Gene-3 (LAG-3) is a well-established co-inhibitory receptor that performs negative regulation on immune responses. Recently, a novel FDA-approved LAG-3 blocking agent, together with nivolumab as a new combinational immunotherapy for metastatic melanoma, brought LAG-3 back into focus. Clinical data suggests that anti-LAG-3 agents can amplify the therapeutic response of other immune checkpoint inhibitors with manageable side effects. In this review, we elucidate the intercellular and intracellular mechanisms of LAG-3, clarify the current understanding of LAG-3 in the tumor microenvironment, identify present LAG-3-associated therapeutic agents, discuss current LAG-3-involving clinical trials, and eventually address future prospects for LAG-3 inhibitors.

Combinatorial blockade for cancer immunotherapy: targeting emerging immune checkpoint receptors

The differentiation, survival, and effector function of tumor-specific CD8+ cytotoxic T cells lie at the center of antitumor immunity. Due to the lack of proper costimulation and the abundant immunosuppressive mechanisms, tumor-specific T cells show a lack of persistence and exhausted and dysfunctional phenotypes. Multiple coinhibitory receptors, such as PD-1, CTLA-4, VISTA, TIGIT, TIM-3, and LAG-3, contribute to dysfunctional CTLs and failed antitumor immunity. These coinhibitory receptors are collectively called immune checkpoint receptors (ICRs). Immune checkpoint inhibitors (ICIs) targeting these ICRs have become the cornerstone for cancer immunotherapy as they have established new clinical paradigms for an expanding range of previously untreatable cancers. Given the nonredundant yet convergent molecular pathways mediated by various ICRs, combinatorial immunotherapies are being tested to bring synergistic benefits to patients. In this review, we summarize the mechanisms of several emerging ICRs, including VISTA, TIGIT, TIM-3, and LAG-3, and the preclinical and clinical data supporting combinatorial strategies to improve existing ICI therapies.

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.

Immune checkpoint inhibitors in non-small cell lung cancer: from current perspectives to future treatments-a systematic review

Background

The introduction of immunotherapy in the treatment of non-small cell lung cancer (NSCLC) has resulted in a radical change in patients' treatment responses and survival rates. The increased percentage of long survivors, improved toxicity profiles compared to chemotherapy, and the possible applications for different NSCLC scenarios, have led to immune checkpoint inhibitors (ICIs) becoming the cornerstone of NSCLC treatment. Therefore, the objective of this review is to describe the current and future perspectives of NSCLC treatment.

Methods

A systematic review according to the PRISMA criteria has been performed based on clinical trials with immunotherapy in NSCLC from the start of these treatments until June 2022.

Results

The use of ICIs is widespread across both first- and second-line treatments with anti-PD-1, anti-PD-L1, and anti-CTLA-4 drugs. New indications for immunotherapy in NSCLC have focused on adjuvant (atezolizumab) and neoadjuvant (nivolumab), with ICIs now present in all stages of NSCLC treatment. Given the promising results seen in clinical trials, new ICIs [anti- lymphocyte activation gene-3 (LAG-3) or IDO1] currently under development, will soon be used as standard treatment for NSCLC.

Conclusions

Immunotherapy is the mainstay of NSCLC treatment in all stages, including adjuvant, neoadjuvant and advanced tumors. The development of new molecules will revolutionize the treatment of NSCLC in the coming years.

LAG-3 Inhibitors: Novel Immune Checkpoint Inhibitors Changing the Landscape of Immunotherapy

One of the most important steps forward in the management of cancer was the discovery of immunotherapy. It has become an essential pillar in the treatment paradigm of cancer patients. Unfortunately, despite the various options presented with immune checkpoint inhibitors (ICIs), the benefit is still limited to select patients and the vast majority of these patients gain either minimal benefit or eventually progress, leaving an unmet need for the development of novel therapeutic agents and strategies. Lymphocyte activation gene-3 (LAG-3), an immune checkpoint receptor protein, is a molecule found on the surface of activated T-cells. It plays a major role in negatively regulating T-cell function thereby providing tumors with an immune escape in the tumor microenvironment (TME). Given its importance in regulating the immune system, LAG-3 has been considered as a promising target in oncology and precision medicine. To date, two LAG-3-directed agents (eftilagimod alpha and relatlimab) have been approved in combination with programmed death-1 (PD-1) inhibitors in the setting of advanced solid tumors. In this review, we discuss the structure of LAG-3, its mechanism of action, and its interaction with its ligands. We also shed light on the emerging treatments targeting LAG-3 for the treatment of solid tumors.

Single-cell sequencing in primary intraocular tumors: understanding heterogeneity, the microenvironment, and drug resistance

Retinoblastoma (RB) and uveal melanoma (UM) are the most common primary intraocular tumors in children and adults, respectively. Despite continued increases in the likelihood of salvaging the eyeball due to advancements in local tumor control, prognosis remains poor once metastasis has occurred. Traditional sequencing technology obtains averaged information from pooled clusters of diverse cells. In contrast, single-cell sequencing (SCS) allows for investigations of tumor biology at the resolution of the individual cell, providing insights into tumor heterogeneity, microenvironmental properties, and cellular genomic mutations. SCS is a powerful tool that can help identify new biomarkers for diagnosis and targeted therapy, which may in turn greatly improve tumor management. In this review, we focus on the application of SCS for evaluating heterogeneity, microenvironmental characteristics, and drug resistance in patients with RB and UM.

Beyond CTLA-4 and PD-1 Inhibition: Novel Immune Checkpoint Molecules for Melanoma Treatment

More than ten years after the approval of ipilimumab, immune checkpoint inhibitors (ICIs) against PD-1 and CTLA-4 have been established as the most effective treatment for locally advanced or metastatic melanoma, achieving durable responses either as monotherapies or in combinatorial regimens. However, a considerable proportion of patients do not respond or experience early relapse, due to multiple parameters that contribute to melanoma resistance. The expression of other immune checkpoints beyond the PD-1 and CTLA-4 molecules remains a major mechanism of immune evasion. The recent approval of anti-LAG-3 ICI, relatlimab, in combination with nivolumab for metastatic disease, has capitalized on the extensive research in the field and has highlighted the potential for further improvement of melanoma prognosis by synergistically blocking additional immune targets with new ICI-doublets, antibody-drug conjugates, or other novel modalities. Herein, we provide a comprehensive overview of presently published immune checkpoint molecules, including LAG-3, TIGIT, TIM-3, VISTA, IDO1/IDO2/TDO, CD27/CD70, CD39/73, HVEM/BTLA/CD160 and B7-H3. Beginning from their immunomodulatory properties as co-inhibitory or co-stimulatory receptors, we present all therapeutic modalities targeting these molecules that have been tested in melanoma treatment either in preclinical or clinical settings. Better understanding of the checkpoint-mediated crosstalk between melanoma and immune effector cells is essential for generating more effective strategies with augmented immune response.

Recent Advances in Molecular Mechanisms of Cancer Immunotherapy

Cancer is among the current leading causes of death worldwide, despite the novel advances that have been made toward its treatment, it is still considered a major public health concern. Considering both the serious impact of cancer on public health and the significant side effects and complications of conventional therapeutic options, the current strategies towards targeted cancer therapy must be enhanced to avoid undesired toxicity. Cancer immunotherapy has become preferable among researchers in recent years compared to conventional therapeutic options, such as chemotherapy, surgery, and radiotherapy. The understanding of how to control immune checkpoints, develop therapeutic cancer vaccines, genetically modify immune cells as well as enhance the activation of antitumor immune response led to the development of novel cancer treatments. In this review, we address recent advances in cancer immunotherapy molecular mechanisms. Different immunotherapeutic approaches are critically discussed, focusing on the challenges, potential risks, and prospects involving their use.

The Role of Different Immunocompetent Cell Populations in the Pathogenesis of Head and Neck Cancer-Regulatory Mechanisms of Pro- and Anti-Cancer Activity and Their Impact on Immunotherapy

Head and neck squamous cell carcinoma (HNSCC) is one of the most aggressive and heterogeneous groups of human neoplasms. HNSCC is characterized by high morbidity, accounting for 3% of all cancers, and high mortality with ~1.5% of all cancer deaths. It was the most common cancer worldwide in 2020, according to the latest GLOBOCAN data, representing the seventh most prevalent human malignancy. Despite great advances in surgical techniques and the application of modern combinations and cytotoxic therapies, HNSCC remains a leading cause of death worldwide with a low overall survival rate not exceeding 40-60% of the patient population. The most common causes of death in patients are its frequent nodal metastases and local neoplastic recurrences, as well as the relatively low response to treatment and severe drug resistance. Much evidence suggests that the tumour microenvironment (TME), tumour infiltrating lymphocytes (TILs) and circulating various subpopulations of immunocompetent cells, such regulatory T cells (CD4+CD25+Foxp3+Tregs), cytotoxic CD3+CD8+ T cells (CTLs) and CD3+CD4+ T helper type 1/2/9/17 (Th1/Th2/Th9/Th17) lymphocytes, T follicular helper cells (Tfh) and CD56dim/CD16bright activated natural killer cells (NK), carcinoma-associated fibroblasts (CAFs), myeloid-derived suppressor cells (MDSCs), tumour-associated neutrophils (N1/N2 TANs), as well as tumour-associated macrophages (M1/M2 phenotype TAMs) can affect initiation, progression and spread of HNSCC and determine the response to immunotherapy. Rapid advances in the field of immuno-oncology and the constantly growing knowledge of the immunosuppressive mechanisms and effects of tumour cancer have allowed for the use of effective and personalized immunotherapy as a first-line therapeutic procedure or an essential component of a combination therapy for primary, relapsed and metastatic HNSCC. This review presents the latest reports and molecular studies regarding the anti-tumour role of selected subpopulations of immunocompetent cells in the pathogenesis of HNSCC, including HPV+ve (HPV+) and HPV-ve (HPV-) tumours. The article focuses on the crucial regulatory mechanisms of pro- and anti-tumour activity, key genetic or epigenetic changes that favour tumour immune escape, and the strategies that the tumour employs to avoid recognition by immunocompetent cells, as well as resistance mechanisms to T and NK cell-based immunotherapy in HNSCC. The present review also provides an overview of the pre- and clinical early trials (I/II phase) and phase-III clinical trials published in this arena, which highlight the unprecedented effectiveness and limitations of immunotherapy in HNSCC, and the emerging issues facing the field of HNSCC immuno-oncology.

Interferon Biology and LAG-3 Shedding in PD-(L)1 plus LAG-3 Immunotherapy

Targeting coinhibitory receptors on dysfunctional T cells may improve response to anti-PD-(L)1 in the IFNγ associated T-cell-inflamed tumor microenvironment. The bispecific lymphocyte activation gene 3 (LAG-3) and PD-L1 blocking antibody FS118, potentially through LAG-3 shedding, represents a promising strategy to improve immune checkpoint blockade. Soluble LAG-3 is an intriguing biomarker for LAG-3 drug activity. See related article by Yap et al., p. 888.

Programmed cell death-1 blockade therapy in melanoma: Resistance mechanisms and combination strategies

Melanoma is a highly aggressive tumor derived from melanocytes. In recent years, the incidence and mortality of melanoma have gradually increased, seriously threatening human health. Classic treatments like surgery, chemotherapy, and radiotherapy show very limited efficacy. Due to the high immunogenicity of melanoma cells, immune checkpoint inhibitors have received considerable attention as melanoma treatments. One such therapy is blockade of programmed cell death-1 (PD-1), which is one of the most important negative immune regulators and is mainly expressed on activated T cells. Disruption of the interactions between PD-1 and its ligands, programmed death-ligand 1 (PD-L1) or programmed death-ligand 2 (PD-L2) rejuvenates exhausted T cells and enhances antitumor immunity. Although PD-1 blockade therapy is widely used in melanoma, a substantial proportion of patients still show no response or short durations of remission. Recent researches have focused on revealing the underlying mechanisms for resistance to this treatment and improving its efficacy through combination therapy. Here, we will introduce the resistance mechanisms associated with PD-1 blockade therapy in melanoma and review the combination therapies available.

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.

Molecular Pathways and Mechanisms of LAG3 in Cancer Therapy

Immunotherapy targeting coinhibitory receptors has been highly successful in treating a wide variety of malignancies; however, only a subset of patients exhibits durable responses. The first FDA-approved immunotherapeutics targeting coinhibitory receptors PD1 and CTLA4, alone or in combination, significantly improved survival but were also accompanied by substantial toxicity in combination. The third FDA-approved immune checkpoint inhibitor targets LAG3, a coinhibitory receptor expressed on activated CD4+ and CD8+ T cells, especially in settings of long-term antigenic stimulation, such as chronic viral infection or cancer. Mechanistically, LAG3 expression limits both the expansion of activated T cells and the size of the memory pool, suggesting that LAG3 may be a promising target for immunotherapy. Importantly, the mechanism(s) by which LAG3 contributes to CD8+ T-cell exhaustion may be distinct from those governed by PD1, indicating that the combination of anti-LAG3 and anti-PD1 may synergistically enhance antitumor immunity. Clinical studies evaluating the role of anti-LAG3 in combination with anti-PD1 are underway, and recent phase III trial results in metastatic melanoma demonstrate both the efficacy and safety of this combination. Further ongoing clinical trials are evaluating this combination across multiple tumor types and the adjuvant setting, with accompanying translational and biomarker-focused studies designed to elucidate the molecular pathways that lead to improved antitumor T-cell responses following dual blockade of PD1 and LAG3. Overall, LAG3 plays an important role in limiting T-cell activation and has now become part of the repertoire of combinatorial immunotherapeutics available for the treatment of metastatic melanoma.

Characteristics of tumor microenvironment and novel immunotherapeutic strategies for non-small cell lung cancer

Immune checkpoint inhibitor-based immunotherapy has revolutionized the treatment approach of non-small cell lung cancer (NSCLC). Monoclonal antibodies against programmed cell death-1 (PD-1) and PD-ligand 1 (PD-L1) are widely used in clinical practice, but other antibodies that can circumvent innate and acquired resistance are bound to undergo preclinical and clinical studies. However, tumor cells can develop and facilitate the tolerogenic nature of the tumor microenvironment (TME), resulting in tumor progression. Therefore, the immune escape mechanisms exploited by growing lung cancer involve a fine interplay between all actors in the TME. A better understanding of the molecular biology of lung cancer and the cellular/molecular mechanisms involved in the crosstalk between lung cancer cells and immune cells in the TME could identify novel therapeutic weapons in the old war against lung cancer. This article discusses the role of TME in the progression of lung cancer and pinpoints possible advances and challenges of immunotherapy for NSCLC.

Approaches for development of LAG-3 inhibitors and the promise they hold as anticancer agents

INTRODUCTION

LAG-3 is considered to be the third point of immunological control in relation to clinical trials that address cancer treatment, only behind PD-1 and CTLA-4, due to its role as a suppressor of the immune response and enhancer of differentiation of Treg cells.

AREAS COVERED

The authors focus on emphasizing the strategy of development of LAG-3 inhibitors to develop anticancer therapeutics, especially from the perspective of designing new monoclonal and bispecific antibodies against LAG-3. This article also covers details of patents and clinical trials of LAG-3 inhibitors reported in the literature. In addition, we highlight as future research challenges the design and development of peptides and small molecules as inhibitors of LAG-3 function.

EXPERT OPINION

Three approaches have been used for the development of LAG-3 inhibitors, and they include inhibitory LAG-3 binding peptides and antagonist monoclonal and multispecific antibodies. These approaches include more than 100 clinical trials of 21 molecules that bind to LAG-3 and block its binding to MHC II. However, these approaches do not cover the design and development of peptides and small molecules that could inhibit the function of LAG-3, for which it is necessary to develop new alternatives that cover this gap.

Combined Vaccination with B Cell Peptides Targeting Her-2/neu and Immune Checkpoints as Emerging Treatment Option in Cancer

The application of monoclonal antibodies (mAbs), targeting tumor-associated (TAAs) or tumor-specific antigens or immune checkpoints (ICs), has shown tremendous success in cancer therapy. However, the application of mAbs suffers from a series of limitations, including the necessity of frequent administration, the limited duration of clinical response and the emergence of frequently pronounced immune-related adverse events. However, the introduction of mAbs has also resulted in a multitude of novel developments for the treatment of cancers, including vaccinations against various tumor cell-associated epitopes. Here, we reviewed recent clinical trials involving combination therapies with mAbs targeting the PD-1/PD-L1 axis and Her-2/neu, which was chosen as a paradigm for a clinically highly relevant TAA. Our recent findings from murine immunizations against the PD-1 pathway and Her-2/neu with peptides representing the mimotopes/B cell peptides of therapeutic antibodies targeting these molecules are an important focus of the present review. Moreover, concerns regarding the safety of vaccination approaches targeting PD-1, in the context of the continuing immune response, as a result of induced immunological memory, are also addressed. Hence, we describe a new frontier of cancer treatment by active immunization using combined mimotopes/B cell peptides aimed at various targets relevant to cancer biology.

Overcoming the therapeutic resistance of hepatomas by targeting the tumor microenvironment

Hepatocellular carcinoma (HCC) accounts for the majority of primary liver cancers and is the third leading cause of cancer-related mortality worldwide. Multifactorial drug resistance is regarded as the major cause of treatment failure in HCC. Accumulating evidence shows that the constituents of the tumor microenvironment (TME), including cancer-associated fibroblasts, tumor vasculature, immune cells, physical factors, cytokines, and exosomes may explain the therapeutic resistance mechanisms in HCC. In recent years, anti-angiogenic drugs and immune checkpoint inhibitors have shown satisfactory results in HCC patients. However, due to enhanced communication between the tumor and TME, the effect of heterogeneity of the microenvironment on therapeutic resistance is particularly complicated, which suggests a more challenging research direction. In addition, it has been reported that the three-dimensional (3D) organoid model derived from patient biopsies is more intuitive to fully understand the role of the TME in acquired resistance. Therefore, in this review, we have focused not only on the mechanisms and targets of therapeutic resistance related to the contents of the TME in HCC but also provide a comprehensive description of 3D models and how they contribute to the exploration of HCC therapies.

Fibrinogen like protein-1 knockdown suppresses the proliferation and metastasis of TU-686 cells and sensitizes laryngeal cancer to LAG-3 blockade

OBJECTIVE

To detect the expression of fibrinogen like protein-1 (FGL-1) in laryngeal cancer and evaluate its effect on tumor proliferation, metastasis, and antitumor immunity.

METHODS

ELISA and immunohistochemistry were performed to detect FGL-1 expression in laryngeal cancer. The effects of FGL-1 knockdown on the proliferation, cell cycle progression, apoptosis, migration, and invasion of laryngeal cancer cells were evaluated by the CCK-8, colony formation, flow cytometry, Transwell migration, and western blot assays. We detected changes in tumorigenesis and drug response in vivo following FGL-1 knockdown as well as the effects of anti-LAG3 immunotherapy. Immunohistochemistry was performed to determine CD8 and LAG-3 expression in mouse tumor tissues.

RESULTS

FGL-1 was highly expressed in the plasma and tumor tissues of laryngeal cancer patients. FGL-1 knockdown suppressed the proliferation of TU-686 cells and inhibited the migration and invasion of laryngeal cancer by blocking epithelial-to-mesenchymal transition. Moreover, silencing FGL-1 inhibited tumorigenicity in vivo and synergized with anti-LAG3 immunotherapy.

CONCLUSIONS

We confirmed the high expression of FGL-1 in laryngeal cancer and identified FGL-1 as a potential marker for immunotherapy in laryngeal cancer.

Current status and perspective of tumor immunotherapy for head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) have a high incidence and mortality rate, and investigating the pathogenesis and potential therapeutic strategies of HNSCC is required for further progress. Immunotherapy is a considerable therapeutic strategy for HNSCC due to its potential to produce a broad and long-lasting antitumor response. However, immune escape, which involves mechanisms including dyregulation of cytokines, perturbation of immune checkpoints, and recruitment of inhibitory cell populations, limit the efficacy of immunotherapy. Currently, multiple immunotherapy strategies for HNSCC have been exploited, including immune checkpoint inhibitors, costimulatory agonists, antigenic vaccines, oncolytic virus therapy, adoptive T cell transfer (ACT), and epidermal growth factor receptor (EGFR)-targeted therapy. Each of these strategies has unique advantages, and the appropriate application of these immunotherapies in HNSCC treatment has significant value for patients. Therefore, this review comprehensively summarizes the mechanisms of immune escape and the characteristics of different immunotherapy strategies in HNSCC to provide a foundation and consideration for the clinical treatment of HNSCC.

Immunotherapy: Reshape the Tumor Immune Microenvironment

Tumor immune microenvironment (TIME) include tumor cells, immune cells, cytokines, etc. The interactions between these components, which are divided into anti-tumor and pro-tumor, determine the trend of anti-tumor immunity. Although the immune system can eliminate tumor through the cancer-immune cycle, tumors appear to eventually evade from immune surveillance by shaping an immunosuppressive microenvironment. Immunotherapy reshapes the TIME and restores the tumor killing ability of anti-tumor immune cells. Herein, we review the function of immune cells within the TIME and discuss the contribution of current mainstream immunotherapeutic approaches to remolding the TIME. Changes in the immune microenvironment in different forms under the intervention of immunotherapy can shed light on better combination treatment strategies.

Charting roadmaps towards novel and safe synergistic immunotherapy combinations

Checkpoint inhibitor-based cancer immunotherapy is often combined in the clinic with other immunotherapy strategies, targeted therapies, chemotherapy or standard-of-care treatments to achieve superior therapeutic efficacy. The large number of immunotherapy combinations that are currently undergoing clinical testing necessitate the establishment of faithful criteria to prioritize optimal combinations with evidence of synergy, to determine their safety and optimal sequence of administration and to identify biomarkers of therapy resistance and response. In this review, we focus on recent developments in immunotherapy combinations and reflect on how combinations should be optimized to maximize the impact of immunotherapy in clinical oncology.

[An Overview and Interpretation of Important Clinical Studies on Non-small Cell Lung Cancer in 2021]

Though the coronavirus disease is still raging in 2021, clinical research on non-small cell lung cancer (NSCLC) did not stop. However, benefiting from advances in lung cancer treatment modality, NSCLC patients have experienced significant improvements in overall survival and quality of life. Currently, research advances on targeted therapy and immunotherapy have together transformed the status of postoperative adjuvant therapy and established a new standard treatment modality for resectable NSCLC. There are equally important research advances in locally advanced and advanced NSCLC, including new treatment modalities, new therapeutic agents, etc., all of which bringing more options for clinical treatment. These therapies will bring changes to NSCLC and will gradually lead to the chronicity of lung cancer in the foreseeable future. Therefore, this paper reviews important studies that will change clinical practice in NSCLC treatment and noteworthy research advances in 2021.
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Mechanisms of Immunotherapy Resistance in Cutaneous Melanoma: Recognizing a Shapeshifter

Melanoma is one of the seven most common cancers in the United States, and its incidence is still increasing. Since 2011, developments in targeted therapies and immunotherapies have been essential for significantly improving overall survival rates. Prior to the advent of targeted and immunotherapies, metastatic melanoma was considered a death sentence, with less than 5% of patients surviving more than 5 years. With the implementation of immunotherapies, approximately half of patients with metastatic melanoma now survive more than 5 years. Unfortunately, this also means that half of the patients with melanoma do not respond to current therapies and live less than 5 years after diagnosis. One major factor that contributes to lower response in this population is acquired or primary resistance to immunotherapies via tumor immune evasion. To improve the overall survival of melanoma patients new treatment strategies must be designed to minimize the risk of acquired resistance and overcome existing primary resistance. In recent years, many advances have been made in identifying and understanding the pathways that contribute to tumor immune evasion throughout the course of immunotherapy treatment. In addition, results from clinical trials focusing on treating patients with immunotherapy-resistant melanoma have reported some initial findings. In this review, we summarize important mechanisms that drive resistance to immunotherapies in patients with cutaneous melanoma. We have focused on tumor intrinsic characteristics of resistance, altered immune function, and systemic factors that contribute to immunotherapy resistance in melanoma. Exploring these pathways will hopefully yield novel strategies to prevent acquired resistance and overcome existing resistance to immunotherapy treatment in patients with cutaneous melanoma.

LAG3-PD-1 Combo Overcome the Disadvantage of Drug Resistance

Although PD-1 blockade therapy has been promising in cancer treatment, only 4% (pancreatic cancer) to 70% (melanoma) of patients have a positive response to this blockade therapy, which is one of its important disadvantages. Therefore, it is important to seek out new targets for cancer immunotherapy to improve the overall response rate in patients. Lymphocyte activation gene-3 (LAG-3), an immune checkpoint receptor, is mainly expressed in activated immune cells. LAG-3 maintains the body’s immune homeostasis under physiological conditions while mediating tumour immune escape. Several preclinical and clinical examinations have shown that LAG-3 blockade effectively alleviates the patient’s tolerance to PD-1 immune checkpoint inhibitors. Moreover, the combination of LAG-3 and PD-1 blockade has good clinical efficacy in cancers. Hence, synchronous LAG-3 and PD-1 inhibition may be a potential new strategy for tumour immunotherapy.

Immunotherapy for head and neck cancer: present and future

Immunotherapy has changed the treatment landscape of Head and Neck cancer (HNC). Different immune checkpoint inhibitors targeting PD-1/PD-L1 axis have been approved for different disease settings and many others, alone or in combination, are currently under investigation. Otherwise, as in other cancer types, efficacy, and resistance mechanisms, are not clearly understood. Considering the heterogeneity of the benefit reported in clinical trials, cost-efficacy analysis and the development of an effective patient selection are encouraged. Different pathways involving innate immunity, regulatory T lymphocytes and microbiome are emerging as new potential biomarkers, supported by preclinical and translational data. In this review we report current evidence on immunotherapy in HNC with updates from the main 2021 oncology events as ASCO, AACR and ESMO meetings. We focus on clinical trials results of single agent and combination immunotherapy in different clinical scenario, from (neo)adjuvant to metastatic setting, describing also novel evidence about efficacy and resistance biomarkers.

Multi-target combinatory strategy to overcome tumor immune escape

Immune therapy has become the fourth approach after surgery, chemotherapy, and radiotherapy in cancer treatment. Many immune checkpoints were identified in the last decade since ipilimumab, which is the first immune checkpoint inhibitor to cytotoxic T-lymphocyte associated protein 4, had been approved by the US Food and Drug Administration (FDA) for the treatment of unresectable or metastatic melanoma in 2011. The use of several antibody drugs that target PD1/PD-L1 for various cancer treatments has been approved by the FDA. However, fewer people are benefitting from immune checkpoint inhibitor treatment in solid cancers. Approximately 80% of patients do not respond appropriately because of primary or acquired therapeutic resistance. Along with the characterization of more immune checkpoints, the combinatory treatment of multiimmune checkpoint inhibitors becomes a new option when monotherapy could not receive a good response. In this work, the author focuses on the combination therapy of multiple immune checkpoints (does not include targeted therapy of oncogenes or chemotherapy), introduces the current progression of multiple immune checkpoints and their related inhibitors, and discusses the advantages of combination therapy, as well as the risk of immune-related adverse events.

Update on lymphocyte-activation gene 3 (LAG-3) in cancers: from biological properties to clinical applications

Immunotherapy that targets checkpoints, especially programmed cell death protein 1 and programmed cell death ligand 1, has revolutionized cancer therapy regimens. The overall response rate to mono-immunotherapy, however, is limited, emphasizing the need to potentiate the efficacy of these regimens. The functions of immune cells are modulated by multiple stimulatory and inhibitory molecules, including lymphocyte activation gene 3 (LAG-3). LAG-3 is co-expressed together with other inhibitory checkpoints and plays key roles in immune suppression. Increasing evidence, particularly in the last 5 years, has shown the potential of LAG-3 blockade in anti-tumor immunity. This review provides an update on the biological properties and clinical applications of LAG-3 in cancers.

Nicotinamide Inhibits T Cell Exhaustion and Increases Differentiation of CD8 Effector T Cells

One of the limitations of immunotherapy is the development of a state referred to as T cell exhaustion (TEx) whereby T cells express inhibitory receptors (IRs) and lose production of effectors involved in killing of their targets. In the present studies we have used the repeated stimulation model with anti CD3 and anti CD28 to understand the factors involved in TEx development and treatments that may reduce changes of TEx. The results show that addition of nicotinamide (NAM) involved in energy supply to cells prevented the development of inhibitory receptors (IRs). This was particularly evident for the IRs CD39, TIM3, and to a lesser extent LAG3 and PD1 expression. NAM also prevented the inhibition of IL-2 and TNFα expression in TEx and induced differentiation of CD4+ and CD8 T cells to effector memory and terminal effector T cells. The present results showed that effects of NAM were linked to regulation of reactive oxygen species (ROS) consistent with previous studies implicating ROS in upregulation of TOX transcription factors that induce TEx. These effects of NAM in reducing changes of TEx and in increasing the differentiation of T cells to effector states appears to have important implications for the use of NAM supplements in immunotherapy against cancers and viral infections and require further exploration in vivo.

Role of the tumor immune microenvironment in tumor immunotherapy

Tumor immunotherapy is considered to be a novel and promising therapy for tumors and it has recently become a hot research topic. The clinical success of tumor immunotherapy has been notable, but it has been less than totally satisfactory because tumor immunotherapy has performed poorly in numerous patients although it has shown appreciable efficacy in some patients. A minority of patients demonstrate durable responses but the majority of patients do not respond to tumor immunotherapy as the tumor immune microenvironment is different in different patients for different tumor types. The success of tumor immunotherapy may be affected by the heterogeneity of the tumor immune microenvironment and its components, as these vary widely during neoplastic progression. The deepening of research and the development of technology have improved our understanding of the complexity and heterogeneity of the tumor immune microenvironment and its components, and their effects on response to tumor immunotherapy. Therefore, investigating the tumor immune microenvironment and its components and elucidating their association with tumor immunotherapy should improve the ability to study, predict and guide immunotherapeutic responsiveness, and uncover new therapeutic targets.

New Strategies and Combinations to Improve Outcomes in Immunotherapy in Metastatic Non-Small-Cell Lung Cancer

Immune checkpoint inhibitors have transformed the treatment of metastatic non-small-cell lung cancer, yielding marked improvements in survival and the potential for durable clinical responses. Primary and acquired resistance to current immune checkpoint inhibitors constitute a key challenge despite the remarkable responses observed in a subset of patients. Multiple novel combination immunotherapy and adoptive cell therapy strategies are presently being developed to address treatment resistance. The success of these strategies hinges upon rational clinical trial design as well as careful consideration of the immunologic mechanisms within the variable tumor immune microenvironment (TIME) which underpin resistance to immunotherapy. Further research is needed to facilitate a deeper understanding of these complex mechanisms within the TIME, which may ultimately provide the key to restoring and enhancing an effective anti-tumor immune response. This review aims to provide an introduction to some of the recent and notable combination immunotherapy and cell therapy strategies used in advanced non-small-cell lung cancer (NSCLC), and the rationale for their use based on current understanding of the anti-tumor immune response and mechanisms of resistance within the TIME.

Seven mysteries of LAG-3: a multi-faceted immune receptor of increasing complexity

Despite three decades of research to its name and increasing interest in immunotherapies that target it, LAG-3 remains an elusive co-inhibitory receptor in comparison to the well-established PD-1 and CTLA-4. As such, LAG-3 targeting therapies have yet to achieve the clinical success of therapies targeting other checkpoints. This could, in part, be attributed to the many unanswered questions that remain regarding LAG-3 biology. Of these, we address: (i) the function of the many LAG-3-ligand interactions, (ii) the hurdles that remain to acquire a high-resolution structure of LAG-3, (iii) the under-studied LAG-3 signal transduction mechanism, (iv) the elusive soluble form of LAG-3, (v) the implications of the lack of (significant) phenotype of LAG-3 knockout mice, (vi) the reports of LAG-3 expression on the epithelium, and (vii) the conflicting reports of LAG-3 expression (and potential contributions to pathology) in the brain. These mysteries which surround LAG-3 highlight how the ever-evolving study of its biology continues to reveal ever-increasing complexity in its role as an immune receptor. Importantly, answering the questions which shroud LAG-3 in mystery will allow the maximum therapeutic benefit of LAG-3 targeting immunotherapies in cancer, autoimmunity and beyond.

Fibrinogen-like protein 1 (FGL1): the next immune checkpoint target

Immune checkpoint therapy has achieved significant efficacy by blocking inhibitory pathways to release the function of T lymphocytes. In the clinic, anti-programmed cell death protein 1/programmed cell death ligand 1 (PD-1/PD-L1) monoclonal antibodies (mAbs) have progressed to first-line monotherapies in certain tumor types. However, the efficacy of anti-PD-1/PD-L1 mAbs is still limited due to toxic side effects and de novo or adaptive resistance. Moreover, other immune checkpoint target and biomarkers for therapeutic response prediction are still lacking; as a biomarker, the PD-L1 (CD274, B7-H1) expression level is not as accurate as required. Hence, it is necessary to seek more representative predictive molecules and potential target molecules for immune checkpoint therapy. Fibrinogen-like protein 1 (FGL1) is a proliferation- and metabolism-related protein secreted by the liver. Multiple studies have confirmed that FGL1 is a newly emerging checkpoint ligand of lymphocyte activation gene 3 (LAG3), emphasizing the potential of targeting FGL1/LAG3 as the next generation of immune checkpoint therapy. In this review, we summarize the substantial regulation mechanisms of FGL1 in physiological and pathological conditions, especially tumor epithelial to mesenchymal transition, immune escape and immune checkpoint blockade resistance, to provide insights for targeting FGL1 in cancer treatment.

Emerging Therapies in the Treatment of Advanced Melanoma

Great strides in immunotherapy and targeted therapy have revolutionized the management of previously devastating, advanced melanomas. Although these subfields continue to progress, novel approaches in intratumoral oncolytic therapy, adoptive cell therapy, and vaccine therapies are being developed as adjuncts or alternatives. Cytokines, meanwhile, are seeing a resurgence as a viable option as well. The array of effective agents will, in the next few years, provide options for therapy not only in the adjuvant or unresectable settings but also in the neoadjuvant settings. Perhaps, too, in earlier stage melanomas.

Intra- and intertumoral heterogeneity of liver metastases in a patient with uveal melanoma revealed by single-cell RNA sequencing

Tumor heterogeneity is a major obstacle to the success of cancer treatment. An accurate understanding and recognition of tumor heterogeneity is critical in the clinical management of cancer patients. Here, we utilized single-cell RNA sequencing (scRNA-seq) to uncover the intra- and intertumoral heterogeneity of liver metastases from a patient with metastatic uveal melanoma. The two metastases analyzed were largely infiltrated by noncancerous cells with significant variability in the proportion of different cell types. Analysis of copy-number variations (CNVs) showed gain of 8q and loss of 6q in both tumors, but loss of Chromosome 3 was only detected in one of the tumors. Single-nucleotide polymorphism (SNP) array revealed a uniparental isodisomy 3 in the tumor with two copies of Chromosome 3, indicating a regain of Chromosome 3 during the development of the metastatic disease. In addition, both tumors harbored subclones with additional CNVs. Pathway enrichment analysis of differentially expressed genes revealed that cancer cells in the metastasis with isodisomy 3 showed up-regulation in epithelial-mesenchymal transition and myogenesis related genes. In contrast, up-regulation in interferon signaling was observed in the metastasis with monosomy 3 and increased T-cell infiltrate. This study highlights the complexity and heterogeneity of different metastases within an individual case of uveal melanoma.

Gene of the month: lymphocyte-activation gene 3 (LAG-3)

Lymphocyte-activation gene 3 (LAG-3) is a coreceptor found on activated T-lymphocytes activated B-lymphocytes and natural killer (NK) cells. It is closely related to CD4 where it shares multiple common and divergent features. It contains specific binding sites with high affinity to major histocompatibility complex (MHC) Class II and functions as an inhibitor of T-cell signalling. Tumour-infiltrating lymphocytes with high LAG-3 expression have been found in many solid tumours including ovarian cancer, melanoma, colorectal cancer and haematological malignancies including Hodgkin and diffuse large B-cell lymphoma. LAG-3 antagonism has been demonstrated to restore the anti-tumourigenic function of T-cells in vivo, however, mechanistic knowledge remains relatively poorly defined. As other immune checkpoint inhibitors have transformed the management of difficult to treat cancers, such as melanoma, it is hoped that LAG-3 might have the same potential. This review will explore LAG-3 modulation as an anticancer therapy, highlighting recent clinical developments.

Therapeutic Advancements Across Clinical Stages in Melanoma, With a Focus on Targeted Immunotherapy

Melanoma is the most fatal skin cancer. In the early stages, it can be safely treated with surgery alone. However, since 2011, there has been an important revolution in the treatment of melanoma with new effective treatments. Targeted therapy and immunotherapy with checkpoint inhibitors have changed the history of this disease. To date, more than half of advanced melanoma patients are alive at 5 years; despite this breakthrough, approximately half of the patients still do not respond to treatment. For these reasons, new therapeutic strategies are required to expand the number of patients who can benefit from immunotherapy or combination with targeted therapy. Current research aims at preventing primary and acquired resistance, which are both responsible for treatment failure in about 50% of patients. This could increase the effectiveness of available drugs and allow for the evaluation of new combinations and new targets. The main pathways and molecules under study are the IDO inhibitor, TLR9 agonist, STING, LAG-3, TIM-3, HDAC inhibitors, pegylated IL-2 (NKTR-214), GITR, and adenosine pathway inhibitors, among others (there are currently about 3000 trials that are evaluating immunotherapeutic combinations in different tumors). Other promising strategies are cancer vaccines and oncolytic viruses. Another approach is to isolate and remove immune cells (DCs, T cells, and NK cells) from the patient's blood or tumor infiltrates, add specific gene fragments, expand them in culture with growth factors, and re-inoculate into the same patient. TILs, TCR gene transfer, and CAR-T therapy follow this approach. In this article, we give an overview over the current status of melanoma therapies, the clinical rationale for choosing treatments, and the new immunotherapy approaches.

Immunotherapy in colorectal cancer

The immune tumor microenvironment (TME) of colorectal cancer (CRC) is a crucial contributor to disease biology, making it an important target for therapeutic intervention. The diversity of immune cell populations within various subsets of CRC has led to the discovery that immune characterization of the TME has both prognostic and predictive value for patients. The convergence of improved molecular and cellular characterization of CRC along with the widespread use of immunotherapy in solid tumors has led to a revolution in the approach to clinical care. Monoclonal antibodies (mAbs) which target key immune checkpoints, such as programmed death-1 (PD-1) and cytotoxic T-lymphocyte antigen 4 (CTLA-4), have demonstrated remarkable clinical activity in microsatellite instability-high (MSI-H) CRCs and are now used in routine practice. The observation that MSI-H cancers are highly infiltrated with immune cells and carry a high neoantigen load led to the successful targeting of these cancers with immunotherapy. More recently, the Food and Drug Administration (FDA) approved a PD-1 inhibitor for microsatellite stable (MSS) cancers with high tumor mutation burden. However, the anti-tumor activity of immunotherapy is rare in the majority of CRC. While immune cell characterization does provide prognostic value in these patients, these observations have not yet led to therapeutic interventions. By delineating factors that predict efficacy, resistance, and therapeutic targets, ongoing research will inform the development of effective combination strategies for the vast majority of MSS CRC and immunotherapy-resistant MSI-H cancers.

Clinical Insights Into Novel Immune Checkpoint Inhibitors

The success of immune checkpoint inhibitors (ICIs), notably anti-cytotoxic T lymphocyte associated antigen-4 (CTLA-4) as well as inhibitors of CTLA-4, programmed death 1 (PD-1), and programmed death ligand-1 (PD-L1), has revolutionized treatment options for solid tumors. However, the lack of response to treatment, in terms of de novo or acquired resistance, and immune related adverse events (IRAE) remain as hurdles. One mechanisms to overcome the limitations of ICIs is to target other immune checkpoints associated with tumor microenvironment. Immune checkpoints such as lymphocyte activation gene-3 (LAG-3), T cell immunoglobulin and ITIM domain (TIGIT), T cell immunoglobulin and mucin-domain containing-3 (TIM-3), V-domain immunoglobulin suppressor of T cell activation (VISTA), B7 homolog 3 protein (B7-H3), inducible T cell costimulatory (ICOS), and B and T lymphocyte attenuator (BTLA) are feasible and promising options for treating solid tumors, and clinical trials are currently under active investigation. This review aims to summarize the clinical aspects of the immune checkpoints and introduce novel agents targeting these checkpoints.

Impact of Immunotherapy on CD4 T Cell Phenotypes and Function in Cancer

Immunotherapy has become a standard treatment in many cancers and it is based on three main therapeutic axes: immune checkpoint blockade (ICB), vaccination and adoptive cell transfer (ACT). If originally these therapies mainly focused on exploiting CD8 T cells given their role in the direct elimination of tumor cells, increasing evidence highlights the crucial role CD4 T cells play in the antitumor immune response. Indeed, these cells can profoundly modulate the tumor microenvironment (TME) by secreting different types of cytokine or by directly eliminating cancer cells. In this review, we describe how different CD4 T cell subsets can contribute to tumor immune responses during immunotherapy and the novel high-throughput immune monitoring tools that are expected to facilitate the study of CD4 T cells, at antigen-specific and single cell level, thus accelerating bench-to-bed translational research in cancer.

Immunophenotyping of Peripheral Blood Mononuclear Cells in Septic Shock Patients With High-Dimensional Flow Cytometry Analysis Reveals Two Subgroups With Differential Responses to Immunostimulant Drugs

Sepsis is associated with a dysregulated inflammatory response to infection. Despite the activation of inflammation, an immune suppression is often observed, predisposing patients to secondary infections. Therapies directed at restoration of immunity may be considered but should be guided by the immune status of the patients. In this paper, we described the use of a high-dimensional flow cytometry (HDCyto) panel to assess the immunophenotype of patients with sepsis. We then isolated peripheral blood mononuclear cells (PBMCs) from patients with septic shock and mimicked a secondary infection by stimulating PBMCs for 4 h in vitro with lipopolysaccharide (LPS) with or without prior exposure to either IFN-γ, or LAG-3Ig. We evaluated the response by means of flow cytometry and high-resolution clustering cum differential analysis and compared the results to PBMCs from healthy donors. We observed a heterogeneous immune response in septic patients and identified two major subgroups: one characterized by hypo-responsiveness (Hypo) and another one by hyper-responsiveness (Hyper). Hypo and Hyper groups showed significant differences in the production of cytokines/chemokine and surface human leukocyte antigen-DR (HLA-DR) expression in response to LPS stimulation, which were observed across all cell types. When pre-treated with either interferon gamma (IFN-γ) or lymphocyte-activation gene 3 (LAG)-3 recombinant fusion protein (LAG-3Ig) prior to LPS stimulation, cells from the Hypo group were shown to be more responsive to both immunostimulants than cells from the Hyper group. Our results demonstrate the importance of patient stratification based on their immune status prior to any immune therapies. Once sufficiently scaled, this approach may be useful for prescribing the right immune therapy for the right patient at the right time, the key to the success of any therapy.

The evolving landscape of immunotherapy in solid tumors

While surgical resection, local and cytotoxic therapies have long formed the basis of cancer care, immunotherapy now plays a key role in supplementing and even replacing these agents in the first line. Here we review the early success of programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte associated protein 4 blockade and discuss biomarkers of therapeutic response. We next highlight a select group of novel targets in Phase III trials both as monotherapies and in combination with PD-1 inhibitors. Finally, we discuss innovations which seek to improve outcomes in therapy-resistant solid tumors.

Fine-Tuning the Tumour Microenvironment: Current Perspectives on the Mechanisms of Tumour Immunosuppression

Immunotherapy has revolutionised the treatment of cancers by harnessing the power of the immune system to eradicate malignant tissue. However, it is well recognised that some cancers are highly resistant to these therapies, which is in part attributed to the immunosuppressive landscape of the tumour microenvironment (TME). The contexture of the TME is highly heterogeneous and contains a complex architecture of immune, stromal, vascular and tumour cells in addition to acellular components such as the extracellular matrix. While understanding the dynamics of the TME has been instrumental in predicting durable responses to immunotherapy and developing new treatment strategies, recent evidence challenges the fundamental paradigms of how tumours can effectively subvert immunosurveillance. Here, we discuss the various immunosuppressive features of the TME and how fine-tuning these mechanisms, rather than ablating them completely, may result in a more comprehensive and balanced anti-tumour response.