A human CD137×PD-L1 bispecific antibody promotes anti-tumor immunity via context-dependent T cell costimulation and checkpoint blockade

Human/mouse CD137 agonist, JNU-0921, effectively shrinks tumors through enhancing the cytotoxicity of CD8+ T cells in cis and in trans

Agonistic antibodies against CD137 have been demonstrated to completely regress established tumors through activating T cell immunity. Unfortunately, current CD137 antibodies failed to benefit patients with cancer. Moreover, their antitumor mechanisms in vivo remain to be determined. Here, we report the development of a small molecular CD137 agonist, JNU-0921. JNU-0921 effectively activates both human and mouse CD137 through direct binding their extracellular domains to induce oligomerization and signaling and effectively shrinks tumors in vivo. Mechanistically, JNU-0921 enhances effector and memory function of cytotoxic CD8+ T cells (CTLs) and alleviates their exhaustion. JNU-0921 also skews polarization of helper T cells toward T helper 1 type and enhances their activity to boost CTL function. Meanwhile, JNU-0921 attenuates the inhibitory function of regulatory T cells on CTLs. Our current work shows that JNU-0921 shrinks tumors by enhancing the cytotoxicity of CTLs in cis and in trans and sheds light on strategy for developing CD137 small molecular agonists.

Clinical Progresses and Challenges of Bispecific Antibodies for the Treatment of Solid Tumors

In recent years, bispecific antibodies (BsAbs) have emerged as a promising therapeutic strategy against tumors. BsAbs can recruit and activate immune cells, block multiple signaling pathways, and deliver therapeutic payloads directly to tumor sites. This review provides a comprehensive overview of the recent advances in the development and clinical application of BsAbs for the treatment of solid tumors. We discuss the different formats, the unique mechanisms of action, and the clinical outcomes of the most advanced BsAbs in solid tumor therapy. Several studies have also analyzed the clinical progress of bispecific antibodies. However, this review distinguishes itself by exploring the challenges associated with bispecific antibodies and proposing potential solutions. As the field progresses, BsAbs hold promise to redefine cancer treatment paradigms and offer new hope to patients with solid tumors.

Takotsubo syndrome as an outcome of the use of checkpoint inhibitor therapy in patients with COVID-19

Takotsubo Syndrome (TS) is a heart disease caused by extreme exposure of the body to physical or psychological stress. In the context of COVID-19, the virus can be a significant source of stress, with particular attention being paid to the cytokine storm as a cause of damage to the body. New research shows that the production of specific cytokines is linked to the activation of immune checkpoint proteins such as PD-1, PD-L1, and CTLA-4 on T cells. Although initially beneficial in combating infections, it can suppress defense and aid in disease progression. Therefore, checkpoint inhibitor therapy has been highlighted beyond oncological therapies, given its effectiveness in strengthening the immune system. However, this treatment can lead to excessive immune responses, inflammation, and stress on the heart, which can cause Takotsubo Syndrome in patients. Several studies investigate the direct link between this therapy and cardiac injuries in these patients, which can trigger TS. From this perspective, we must delve deeper into this treatment and consider its effects on the prognosis against SARS-CoV-2 infection.

ABIN1 is a negative regulator of effector functions in cytotoxic T cells

T cells are pivotal in the adaptive immune defense, necessitating a delicate balance between robust response against infections and self-tolerance. Their activation involves intricate cross-talk among signaling pathways triggered by the T-cell antigen receptors (TCR) and co-stimulatory or inhibitory receptors. The molecular regulation of these complex signaling networks is still incompletely understood. Here, we identify the adaptor protein ABIN1 as a component of the signaling complexes of GITR and OX40 co-stimulation receptors. T cells lacking ABIN1 are hyper-responsive ex vivo, exhibit enhanced responses to cognate infections, and superior ability to induce experimental autoimmune diabetes in mice. ABIN1 negatively regulates p38 kinase activation and late NF-κB target genes. P38 is at least partially responsible for the upregulation of the key effector proteins IFNG and GZMB in ABIN1-deficient T cells after TCR stimulation. Our findings reveal the intricate role of ABIN1 in T-cell regulation.

Technical considerations and strategies for generating and optimizing humanized mouse tumor models in immuno-oncology research

The field of cancer immunotherapy has experienced significant progress, resulting in the emergence of numerous biological drug candidates requiring in vivo efficacy testing and a better understanding of their mechanism of action (MOA). Humanized immune system (HIS) models are valuable tools in this regard. However, there is a lack of systematic guidance on HIS modeling. To address this issue, the present study aimed to establish and optimize a variety of HIS models for immune-oncology (IO) study, including genetically engineered mouse models and HIS models with human immune components reconstituted in severely immunocompromised mice. The efficacy and utility of these models were tested with several marketed or investigational IO drugs according to their MOA, followed by immunophenotypic analysis and efficacy evaluation. The results of the present study demonstrated that the HIS models responded to various IO drugs as expected and that each model had unique niches, utilities and limitations. Researchers should carefully choose the appropriate models based on the MOA and the targeted immune cell populations of the investigational drug. The present study provides valuable methodologies and actionable technical guidance on designing, generating or utilizing appropriate HIS models to address specific questions in translational IO.

CAR-NKT Cells in Asthma: Use of NKT as a Promising Cell for CAR Therapy

NKT cells, unique lymphocytes bridging innate and adaptive immunity, offer significant potential for managing inflammatory disorders like asthma. Activating iNKT induces increasing IFN-γ, TGF-β, IL-2, and IL-10 potentially suppressing allergic asthma. However, their immunomodulatory effects, including granzyme-perforin-mediated cytotoxicity, and expression of TIM-3 and TRAIL warrant careful consideration and targeted approaches. Although CAR-T cell therapy has achieved remarkable success in treating certain cancers, its limitations necessitate exploring alternative approaches. In this context, CAR-NKT cells emerge as a promising approach for overcoming these challenges, potentially achieving safer and more effective immunotherapies. Strategies involve targeting distinct IgE-receptors and their interactions with CAR-NKT cells, potentially disrupting allergen-mast cell/basophil interactions and preventing inflammatory cytokine release. Additionally, targeting immune checkpoints like PDL-2, inducible ICOS, FASL, CTLA-4, and CD137 or dectin-1 for fungal asthma could further modulate immune responses. Furthermore, artificial intelligence and machine learning hold immense promise for revolutionizing NKT cell-based asthma therapy. AI can optimize CAR-NKT cell functionalities, design personalized treatment strategies, and unlock a future of precise and effective care. This review discusses various approaches to enhancing CAR-NKT cell efficacy and longevity, along with the challenges and opportunities they present in the treatment of allergic asthma.

Bispecific antibodies for multiple myeloma: past, present and future

Despite the development of various therapeutic agents, multiple myeloma remains incurable. Recently, T-cell redirected immunotherapy has become a promising strategy for the treatment of refractory myeloma. Clinical trials using chimeric antigen receptor (CAR)-T cells and bispecific antibodies have demonstrated successful anti-myeloma responses in triple-class-refractory patients. However, unique and unwanted immune effects associated with on-target/off-target reactivity of activated immune cells need to be considered and properly managed. This review summarizes recent advances in bispecific antibodies for the treatment of refractory myeloma. It outlines the history of their development, along with a discussion of their mechanisms of action and their current and potential future role in myeloma therapy. As more evidence emerges to inform the timing of CAR-T-cell therapy, the results of clinical trials and off-the-shelf nature of bispecifics also suggest the timing of their treatment. These findings will promote further development and application of bispecifics for refractory myeloma in combination with other appropriate agents.

Tumor-Agnostic Therapy-The Final Step Forward in the Cure for Human Neoplasms?

Cancer accounted for 10 million deaths in 2020, nearly one in every six deaths annually. Despite advancements, the contemporary clinical management of human neoplasms faces a number of challenges. Surgical removal of tumor tissues is often not possible technically, while radiation and chemotherapy pose the risk of damaging healthy cells, tissues, and organs, presenting complex clinical challenges. These require a paradigm shift in developing new therapeutic modalities moving towards a more personalized and targeted approach. The tumor-agnostic philosophy, one of these new modalities, focuses on characteristic molecular signatures of transformed cells independently of their traditional histopathological classification. These include commonly occurring DNA aberrations in cancer cells, shared metabolic features of their homeostasis or immune evasion measures of the tumor tissues. The first dedicated, FDA-approved tumor-agnostic agent's profound progression-free survival of 78% in mismatch repair-deficient colorectal cancer paved the way for the accelerated FDA approvals of novel tumor-agnostic therapeutic compounds. Here, we review the historical background, current status, and future perspectives of this new era of clinical oncology.

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.

ATG-101 Is a Tetravalent PD-L1×4-1BB Bispecific Antibody That Stimulates Antitumor Immunity through PD-L1 Blockade and PD-L1-Directed 4-1BB Activation

Immune checkpoint inhibitors (ICI) have transformed cancer treatment. However, only a minority of patients achieve a profound response. Many patients are innately resistant while others acquire resistance to ICIs. Furthermore, hepatotoxicity and suboptimal efficacy have hampered the clinical development of agonists of 4-1BB, a promising immune-stimulating target. To effectively target 4-1BB and treat diseases resistant to ICIs, we engineered ATG-101, a tetravalent "2+2″ PD-L1×4-1BB bispecific antibody. ATG-101 bound PD-L1 and 4-1BB concurrently, with a greater affinity for PD-L1, and potently activated 4-1BB+ T cells when cross-linked with PD-L1-positive cells. ATG-101 activated exhausted T cells upon PD-L1 binding, indicating a possible role in reversing T-cell dysfunction. ATG-101 displayed potent antitumor activity in numerous in vivo tumor models, including those resistant or refractory to ICIs. ATG-101 greatly increased the proliferation of CD8+ T cells, the infiltration of effector memory T cells, and the ratio of CD8+ T/regulatory T cells in the tumor microenvironment (TME), rendering an immunologically "cold" tumor "hot." Comprehensive characterization of the TME after ATG-101 treatment using single-cell RNA sequencing further revealed an altered immune landscape that reflected increased antitumor immunity. ATG-101 was well tolerated and did not induce hepatotoxicity in non-human primates. According to computational semimechanistic pharmacology modeling, 4-1BB/ATG-101/PD-L1 trimer formation and PD-L1 receptor occupancy were both maximized at around 2 mg/kg of ATG-101, providing guidance regarding the optimal biological dose for clinical trials. In summary, by localizing to PD-L1-rich microenvironments and activating 4-1BB+ immune cells in a PD-L1 cross-linking-dependent manner, ATG-101 safely inhibits growth of ICI resistant and refractory tumors.

SIGNIFICANCE

The tetravalent PD-L1×4-1BB bispecific antibody ATG-101 activates 4-1BB+ T cells in a PD-L1 cross-linking-dependent manner, minimizing the hepatotoxicity of existing 4-1BB agonists and suppressing growth of ICI-resistant tumors. See related commentary by Ha et al., p. 1546.

Striking the Balance with a PD-L1×4-1BB Bispecific Antibody

Antibody-based immune checkpoint blockade therapy has revolutionized the field of cancer immunotherapy, yet its efficacy remains limited in immunologically cold tumors. Combining checkpoint inhibitors with costimulatory agonists improves tumoricidal activity of T cells but also can lead to off-target hepatotoxicity. Although bispecific antibodies confer tumor selectivity to alleviate undesirable adverse effects, toxicity concerns persist with increased dosing. In this issue of Cancer Research, Yuwen and colleagues introduce ATG-101, a tetravalent PD-L1×4-1BB bispecific antibody with high programmed death ligand 1 (PD-L1) affinity and low 4-1BB affinity, aiming to mitigate hepatotoxicity. ATG-101 demonstrates PD-L1-dependent 4-1BB activation, leading to selective T-cell activation within the tumor microenvironment. ATG-101 exhibits potent antitumor activity, even in large, immunologically cold, and monotherapy-resistant tumor models. Single-cell RNA sequencing reveals significant shifts of immune cell populations in the tumor microenvironment from protumor to antitumor phenotypes following ATG-101 treatment. In cynomolgus monkeys, no serious cytokine storm and hepatotoxicity are observed after ATG-101 treatment, indicating a broad therapeutic window for ATG-101 in cancer treatment. This study highlights the potential of tetravalent bispecific antibodies in cancer immunotherapy, with implications for various antibody-based treatment modalities across different fields. See related article by Yuwen et al., p. 1680.

Immune cell-related prognostic risk model and tumor immune environment modulation in esophageal carcinoma based on single-cell and bulk RNA sequencing

BACKGROUND

Immune cells play a pivotal role in the tumor microenvironment, exerting significant influence on tumor progression and patient outcomes, but the current biomarkers are insufficient to fully capture the complex and diverse tumor immune microenvironment and the impact of immunotherapy.

METHODS

The advent of single-cell sequencing allows us to explore the tumor microenvironment at an unprecedented resolution, enabling the identification and characterization of distinct subsets of immune cells, thereby paving the way for the development of prognostic models using immune cells. Leveraging single-cell data, our study deeply investigated the intricacies of immune microenvironment heterogeneity in esophageal carcinoma.

RESULTS

We elucidated the composition, functionality, evolution, and intercellular communication patterns of immune cells, culminating in the construction of an independent prognostic model at the single-cell level. Furthermore, we conducted a comprehensive analysis of disparities in immune infiltration and immune checkpoint expression between patients categorized into high- and low-risk groups, which may impact patient prognosis.

CONCLUSION

In summary, our study harnessed multiomics data to delineate the immune profile of esophageal carcinoma patients, provide a method for leveraging molecular signatures of immune cells to identify potential biomarkers, while concurrently providing evidence for the potential benefits of immunotherapy.

Modeling T cell temporal response to cancer immunotherapy rationalizes development of combinatorial treatment protocols

Successful immunotherapy relies on triggering complex responses involving T cell dynamics in tumors and the periphery. Characterizing these responses remains challenging using static human single-cell atlases or mouse models. To address this, we developed a framework for in vivo tracking of tumor-specific CD8+ T cells over time and at single-cell resolution. Our tools facilitate the modeling of gene program dynamics in the tumor microenvironment (TME) and the tumor-draining lymph node (tdLN). Using this approach, we characterize two modes of anti-programmed cell death protein 1 (PD-1) activity, decoupling induced differentiation of tumor-specific activated precursor cells from conventional type 1 dendritic cell (cDC1)-dependent proliferation and recruitment to the TME. We demonstrate that combining anti-PD-1 therapy with anti-4-1BB agonist enhances the recruitment and proliferation of activated precursors, resulting in tumor control. These data suggest that effective response to anti-PD-1 therapy is dependent on sufficient influx of activated precursor CD8+ cells to the TME and highlight the importance of understanding system-level dynamics in optimizing immunotherapies.

Characterization of a Trispecific PD-L1 Blocking Antibody That Exhibits EGFR-Conditional 4-1BB Agonist Activity

Immune checkpoint blockade has changed the treatment paradigm for advanced solid tumors, but the overall response rates are still limited. The combination of checkpoint blockade with anti-4-1BB antibodies to stimulate tumor-infiltrating T cells has shown anti-tumor activity in human trials. However, the further clinical development of these antibodies has been hampered by significant off-tumor toxicities. Here, we generated an anti-4-1BB/EGFR/PD-L1 trispecific antibody consisting of a triple-targeting tandem trimerbody (TT) fused to an engineered silent Fc region. This antibody (IgTT-4E1-S) was designed to combine the blockade of the PD-L1/PD-1 axis with conditional 4-1BB costimulation specifically confined to the tumor microenvironment (TME). The antibody demonstrated simultaneous binding to purified EGFR, PD-L1, and 4-1BB in solution, effective blockade of the PD-L1/PD1 interaction, and potent 4-1BB-mediated costimulation, but only in the presence of EGFR-expressing cells. These results demonstrate the feasibility of IgTT-4E1-S specifically blocking the PD-L1/PD-1 axis and inducing EGFR-conditional 4-1BB agonist activity.

Prognostic Significance of the Microenvironment in Human Papillomavirus Oropharyngeal Carcinoma: A Systematic Review

OBJECTIVE

The immune microenvironment of HPV-associated (HPV+) oropharyngeal squamous cell carcinomas (OPSCCs) (HPV+OPSCCs) differs from that of HPV-independent oropharyngeal cancers (HPV-independent OPSCCs). The literature on the subject is very abundant, demanding an organized synthesis of this wealth of information to evaluate the hypothesis associating the favorable prognosis of HPV+OPSCC patients with a different immune microenvironment. A systematic review of the literature was conducted regarding the microenvironment of HPV+OPSCCs.

DATA SOURCE

MEDLINE/PubMed, Embase, and Cochrane Library databases.

REVIEW METHODS

A literature search was performed following PRISMA guidelines (Moher D. PLoS Med. 2009). The PEO (Population, Exposure, and Outcome) framework is detailed as follows: P: patients with oropharyngeal squamous cell carcinomas, E: human papillomavirus (HPV), and O: histological and immunological composition of the tumoral microenvironment (TME). No meta-analysis was performed.

RESULTS

From 1,202 studies that were screened, 58 studies were included (n = 6,474 patients; n = 3,581 (55%) HPV+OPSCCs and n = 2,861(45%) HPV-independent OPSCCs). The presence of tumor-infiltrating lymphocytes (TIL), CD3+ in 1,733 patients, CD4+ in 520 patients, and CD8+ (cytotoxic T lymphocytes (CTL)) in 3,104 patients, and high levels of PD-L1 expression in 1,222 patients is strongly correlated with an improved clinical outcome in HPV+OPSCCs.

CONCLUSION

This systematic review provides the most comprehensive information on the immune microenvironment of HPV+OPSCCs to date. Tumor-infiltrating lymphocytes and PD-L1 expression are associated with a favorable prognosis. B, CD8+ and resident memory cells densities are higher in HPV+OPSCCs. The importance of myeloid lineages is still a matter of debate and research.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:1507-1516, 2024.

The present and future of bispecific antibodies for cancer therapy

Bispecific antibodies (bsAbs) enable novel mechanisms of action and/or therapeutic applications that cannot be achieved using conventional IgG-based antibodies. Consequently, development of these molecules has garnered substantial interest in the past decade and, as of the end of 2023, 14 bsAbs have been approved: 11 for the treatment of cancer and 3 for non-oncology indications. bsAbs are available in different formats, address different targets and mediate anticancer function via different molecular mechanisms. Here, we provide an overview of recent developments in the field of bsAbs for cancer therapy. We focus on bsAbs that are approved or in clinical development, including bsAb-mediated dual modulators of signalling pathways, tumour-targeted receptor agonists, bsAb-drug conjugates, bispecific T cell, natural killer cell and innate immune cell engagers, and bispecific checkpoint inhibitors and co-stimulators. Finally, we provide an outlook into next-generation bsAbs in earlier stages of development, including trispecifics, bsAb prodrugs, bsAbs that induce degradation of tumour targets and bsAbs acting as cytokine mimetics.

The enhanced antitumor activity of bispecific antibody targeting PD-1/PD-L1 signaling

The programmed cell death 1 (PD-1) signaling pathway, a key player in immune checkpoint regulation, has become a focal point in cancer immunotherapy. In the context of cancer, upregulated PD-L1 on tumor cells can result in T cell exhaustion and immune evasion, fostering tumor progression. The advent of PD-1/PD-L1 inhibitor has demonstrated clinical success by unleashing T cells from exhaustion. Nevertheless, challenges such as resistance and adverse effects have spurred the exploration of innovative strategies, with bispecific antibodies (BsAbs) emerging as a promising frontier. BsAbs offer a multifaceted approach to cancer immunotherapy by simultaneously targeting PD-L1 and other immune regulatory molecules. We focus on recent advancements in PD-1/PD-L1 therapy with a particular emphasis on the development and potential of BsAbs, especially in the context of solid tumors. Various BsAb products targeting PD-1 signaling are discussed, highlighting their unique mechanisms of action and therapeutic potential. Noteworthy examples include anti-TGFβ × PD-L1, anti-CD47 × PD-L1, anti-VEGF × PD-L1, anti-4-1BB × PD-L1, anti-LAG-3 × PD-L1, and anti-PD-1 × CTLA-4 BsAbs. Besides, we summarize ongoing clinical studies evaluating the efficacy and safety of these innovative BsAb agents. By unraveling the intricacies of the tumor microenvironment and harnessing the synergistic effects of anti-PD-1/PD-L1 BsAbs, there exists the potential to elevate the precision and efficacy of cancer immunotherapy, ultimately enabling the development of personalized treatment strategies tailored to individual patient profiles.

Enhancing anti-CD274 (PD-L1) targeting through combinatorial immunotherapy with bispecific antibodies and fusion proteins: from preclinical to phase II clinical trials

INTRODUCTION

Immune checkpoint inhibitors have achieved great success in the treatment of many different types of cancer. Programmed cell death protein ligand 1 (PD-L1, CD274) is a major immunosuppressive immune checkpoint and a target for several already approved monoclonal antibodies. Despite this, novel strategies are under development, as the overall response remains low.

AREAS COVERED

In this review, an overview of the current biomarkers for response to PD-L1 inhibitor treatment is given, followed by a discussion of potential novel biomarkers, including tumor mutational burden and circulating tumor DNA. Combinatorial immunotherapy is a potential novel strategy to increase the response to PD-L1 inhibitor treatment and currently, several interesting bispecific antibodies as well as bispecific fusion proteins are undergoing early clinical investigation. We focus on substances targeting PD-L1 and a secondary target, and a secondary immunomodulatory target like CTLA-4, TIGIT, or CD47.

EXPERT OPINION

Overall, the presented studies show anti-tumor activity of these combinatorial immunotherapeutic approaches. However, still relatively low response rates suggest a need for better biomarkers.

Hypothesis of a CD137/Eomes activating axis for effector T cells in HPV oropharyngeal cancers

Chronic Human Papilloma Virus (HPV) infection is supplanting alcohol and tobacco intoxications as the leading cause of oropharyngeal cancer in developed countries. HPV-related squamous cell carcinomas of the oropharynx (HPV + OSC) present better survival and respond better to radiotherapy and chemotherapy. Regulatory T cells (TREG) are mainly described as immunosuppressive and protumoral in most solid cancers. However, TREG are paradoxically associated with a better prognosis in HPV + OSCs. The transcription factor FoxP3 is the basis for the identification of TREG. Among CD4 + FoxP3 + T cells, some have effector functions. A medical hypothesis is formulated here: the existence of a CD137 (4.1BB)-Eomesodermin (Eomes) activated pathway downstream of TCR-specific activation in a subpopulation of CD4 + FoxP3 + T cells may explain this effector function. Evidence suggest that this axis may exist either in CD4 + FoxP3 + T cells or CD8 + T cells. This pathway could lead T cells to strong antitumor cytotoxic activity in a tumor-specific manner. Furthermore, CD137 is one of the most expected targets for the development of agonist immunotherapies. The identification of CD137 + Eomes + FoxP3+/- T cells could be a key element in the selective activation of the most anti-tumor cells in the HPV + OSC microenvironment.

NSCLC: from tumorigenesis, immune checkpoint misuse to current and future targeted therapy

Non-small cell lung cancer (NSCLC) is largely promoted by a multistep tumorigenesis process involving various genetic and epigenetic alterations, which essentially contribute to the high incidence of mortality among patients with NSCLC. Clinical observations revealed that NSCLC also co-opts a multifaceted immune checkpoint dysregulation as an important driving factor in NSCLC progression and development. For example, a deregulated PI3K/AKT/mTOR pathway has been noticed in 50-70% of NSCLC cases, primarily modulated by mutations in key oncogenes such as ALK, EGFR, KRAS, and others. Additionally, genetic association studies containing patient-specific factors and local reimbursement criteria expose/reveal mutations in EGFR/ALK/ROS/BRAF/KRAS/PD-L1 proteins to determine the suitability of available immunotherapy or tyrosine kinase inhibitor therapy. Thus, the expression of such checkpoints on tumors and immune cells is pivotal in understanding the therapeutic efficacy and has been extensively studied for NSCLC treatments. Therefore, this review summarizes current knowledge in NSCLC tumorigenesis, focusing on its genetic and epigenetic intricacies, immune checkpoint dysregulation, and the evolving landscape of targeted therapies. In the context of current and future therapies, we emphasize the significance of antibodies targeting PD-1/PD-L1 and CTLA-4 interactions as the primary therapeutic strategy for immune system reactivation in NSCLC. Other approaches involving the promising potential of nanobodies, probodies, affibodies, and DARPINs targeting immune checkpoints are also described; these are under active research or clinical trials to mediate immune regulation and reduce cancer progression. This comprehensive review underscores the multifaceted nature, current state and future directions of NSCLC research and treatment.

4-1BB immunotherapy: advances and hurdles

Since its initial description 35 years ago as an inducible molecule expressed in cytotoxic and helper T cells, 4-1BB has emerged as a crucial receptor in T-cell-mediated immune functions. Numerous studies have demonstrated the involvement of 4-1BB in infection and tumor immunity. However, the clinical development of 4-1BB agonist antibodies has been impeded by the occurrence of strong adverse events, notably hepatotoxicity, even though these antibodies have exhibited tremendous promise in in vivo tumor models. Efforts are currently underway to develop a new generation of agonist antibodies and recombinant proteins with modified effector functions that can harness the potent T-cell modulation properties of 4-1BB while mitigating adverse effects. In this review, we briefly examine the role of 4-1BB in T-cell biology, explore its clinical applications, and discuss future prospects in the field of 4-1BB agonist immunotherapy.

Immune checkpoint blockade in hematological malignancies: current state and future potential

Malignant cells are known to evade immune surveillance by engaging immune checkpoints which are negative regulators of the immune system. By restoring the T-lymphocyte mediated anti-tumor effect, immune checkpoint inhibitors (ICI) have revolutionized the treatment of solid tumors but have met rather modest success in hematological malignancies. Currently, the only FDA approved indications for ICI therapy are in classic hodgkin lymphoma and primary mediastinal B cell lymphoma. Multiple clinical trials have assessed ICI therapy alone and in combination with standard of care treatments in other lymphomas, plasma cell neoplasms and myeloid neoplasms but were noted to have limited efficacy. These trials mostly focused on PD-1/PDL-1 and CTLA-4 inhibitors. Recently, there has been an effort to target other T-lymphocyte checkpoints like LAG-3, TIM-3, TIGIT along with improving strategies of PD-1/PDL-1 and CTLA-4 inhibition. Drugs targeting the macrophage checkpoint, CD47, are also being tested. Long term safety and efficacy data from these ongoing studies are eagerly awaited. In this comprehensive review, we discuss the mechanism of immune checkpoint inhibitors, the key takeaways from the reported results of completed and ongoing studies of these therapies in the context of hematological malignancies.

TRIB3, as a robust prognostic biomarker for HNSC, is associated with poor immune infiltration and cancer cell immune evasion

Objective

As a pseudokinase, Tribbles Pseudokinase 3 (TRIB3) is implicated in a wide array of biological processes, including cell signal transduction, metabolic regulation, stress responses, and immune regulation. While its significant role in the immune regulation of certain cancers is well-established, the specific functions and impact of TRIB3 in head and neck squamous cell carcinoma (HNSC) remain unclear.

Methods

The data of RNA-sequence was acquired from the TCGA database to analyze the expression patterns of TRIB3 and elucidate its prognostic value in HNSC patients. Furthermore, the correlation between TRIB3 and tumor mutation burden, clinical data, immune checkpoint genes, and immune cell infiltration was explored. Moreover, the TRIB3 location in tumor tissues and subcellular structures was identified via Tisch in the HPA database, and the potential protein interaction molecules for TRIB3 were elucidated in the STRING database. The potential TRIB3 gene function was assessed using gene set enrichment analysis (GSEA), whereas the TRIB3 expression levels in clinical HNSC samples were verified by RT-qPCR and immunohistochemistry. the role of TRIB3 in enhancing the malignant behavior of HNSC cells was validated in vitro through a series of methods including RT-qPCR, CCK8 assay, wound healing assay, and transwell assay.

Results

It was revealed that TRIB3 was significantly overexpressed in the nucleus and cytoplasm of HNSC. Furthermore, this overexpression markedly enhanced the migration ability of tumor cells. As an independent prognostic factor, TRIB3 was associated with advanced tumor T stage and was significantly involved with tumor mutation burden and immune cell infiltration in HNSC. Moreover, it was observed that TRIB3 was not a predicted factor for PD1/PDL1 and ATL4 inhibitor treatment; however, it was substantially correlated with various immune evasion-related genes in HNSC.

Conclusion

TRIB3 could serve as a potential prognostic marker for HNSC and might be a key gene mediating HNSC immune evasion.

Acral melanoma: new insights into the immune and genomic landscape

Acral melanoma is a rare subtype of melanoma that arises on the non-hair bearing skin of the nail bed, palms of the hand and soles of the feet. It is unique among melanomas in not being linked to ultraviolet radiation (UVR) exposure from the sun, and, as such, its incidence is similar across populations who are of Asian, Hispanic, African and European origin. Although research into acral melanoma has lagged behind that of sun-exposed cutaneous melanoma, recent studies have begun to address the unique genetics and immune features of acral melanoma. In this review we will discuss the latest progress in understanding the biology of acral melanoma across different ethnic populations and will outline how these new discoveries can help to guide the therapeutic management of this rare tumor.

Changing Trends in B-Cell Non-Hodgkin Lymphoma Treatment: The Role of Novel Monoclonal Antibodies in Clinical Practice

We are currently witnessing a dramatic shift in our approach to the treatment of B-cell non-Hodgkin lymphoma (B-NHL). In the evolving clinical landscape, novel treatments for this clinically heterogeneous disease span a wide range of interventions, encompassing targeted agents, cell therapy approaches, and novel monoclonal antibodies (NMABs). Among these, the latter are likely to exert the most profound impact due to their distinctive high efficacy and versatile applicability. NMABs represent a heterogeneous group of agents, including naked antibodies, immunotoxins, and T-cell-engaging molecules. In recent times, several NMABs have either gained regulatory approval or are on the verge of introduction into clinical practice, addressing multiple therapeutic indications and treatment regimens. Their anticipated impact is expected to be broad, initially in the context of relapsed/refractory (R/R) disease and subsequently extending to early treatment lines. The scope of this review is to provide a comprehensive overview of the biological characteristics, clinical properties, efficacy, and toxicity profiles of NMABs that have recently been introduced or are nearing integration into clinical practice.

4-1BB Targeting Immunotherapy: Mechanism, Antibodies, and Chimeric Antigen Receptor T

4-1BB (CD137, TNFRSF9) is a type I transmembrane protein which binds its natural ligand, 4-1BBL. This interaction has been exploited to improve cancer immunotherapy. With ligand binding by 4-1BB, the nuclear factor-kappa B signaling pathway is activated, which results in transcription of corresponding genes such as interleukin-2 and interferon-γ, as well as the induction of T cell proliferation and antiapoptotic signals. Moreover, monoclonal antibodies that target-4-1BB, for example, Urelumab and Utomilumab, are widely used in the treatments of B cell non-Hodgkin lymphoma, lung cancer, breast cancer, soft tissue sarcoma, and other solid tumors. Furthermore, 4-1BB as a costimulatory domain, for chimeric antigen receptor T (CAR-T) cells, improves T cell proliferation and survival as well as reduces T cell exhaustion. As such, a deeper understanding of 4-1BB will contribute to improvements in cancer immunotherapy. This review provides a comprehensive analysis of current 4-1BB studies, with a focus on the use of targeting-4-1BB antibodies and 4-1BB activation domains in CAR-T cells for the treatment of cancer.

Agonism of 4-1BB for immune therapy: a perspective on possibilities and complications

Costimulatory receptors on immune cells represent attractive targets for immunotherapy given that these molecules can increase the frequency of individual protective immune cell populations and their longevity, as well as enhance various effector functions. 4-1BB, a member of the TNF receptor superfamily, also known as CD137 and TNFRSF9, is one such molecule that is inducible on several cell types, including T cells and NK cells. Preclinical studies in animal models have validated the notion that stimulating 4-1BB with agonist reagents or its natural ligand could be useful to augment conventional T cell and NK cell immunity to protect against tumor growth and against viral infection. Additionally, stimulating 4-1BB can enhance regulatory T cell function and might be useful in the right context for suppressing autoimmunity. Two human agonist antibodies to 4-1BB have been produced and tested in clinical trials for cancer, with variable results, leading to the production of a wealth of second-generation antibody constructs, including bi- and multi-specifics, with the hope of optimizing activity and selectivity. Here, we review the progress to date in agonism of 4-1BB, discuss the complications in targeting the immune system appropriately to elicit the desired activity, together with challenges in engineering agonists, and highlight the untapped potential of manipulating this molecule in infectious disease and autoimmunity.

Construction and comprehensive analysis of a novel prognostic signature associated with immunogenic cell death molecular subtypes in patients with bladder cancer

Background

Immunogenic cell death (ICD) triggers adaptive immune responses that aid in anticancer therapy. However, the significance of ICD-associated genes (ICDAGs) in clinical applications and their potential impact on the tumor microenvironment (TME) remains unclear.

Methods

The TCGA cohort was divided into different ICD clusters using the method of Consensus clustering. We assessed the clinical results and TME features of various ICD clusters. GSVA quantified the activation of hallmark gene sets. To establish an ICD molecular subtypes-related prognostic model (ICDRPM), we performed LASSO Cox regression analysis on the differentially expressed genes (DEGs) among ICD subtypes. We evaluated the assessment of risk groups by analyzing the proportion of immune cells, the TME, differences in genomic mutation, the efficacy of immunotherapy, and drug sensitivity. To enhance the clinical effectiveness of the ICDRPM, a nomograph was developed.

Results

Two distinct molecular subtypes were identified, and changes in ICDRGs were associated with clinical outcomes and TME characteristics of patients. A total of 1162 differentially expressed genes (DEGs) were obtained from two ICD clusters, and an ICDRPS was then developed to predict overall survival (OS). During both internal and external validation, patients classified as high-risk exhibited significantly poorer overall survival compared to those classified as low-risk. Additionally, the ICDRPS (ICD_score) was identified as an independent prognostic indicator for patients with BC, demonstrating excellent predictive performance. Afterward, we constructed a dependable nomogram to improve the practicality of the ICD_score. Furthermore, low-risk individuals showed stronger immunocyte infiltration, higher immune checkpoint expression, and higher IPS-PD-1 combined IPS-CTLA4 scores, indicating a greater response to immune checkpoint inhibitors (ICIs). Moreover, individuals categorized as having low or high risk exhibited contrasting sensitivity to anticancer medications.

Conclusions

The model constructed for genes related to ICD provided meaningful clinical implications for immunotherapy, and facilitated individualized treatment for BC patients.

TCR-independent CD137 (4-1BB) signaling promotes CD8+-exhausted T cell proliferation and terminal differentiation

CD137 (4-1BB)-activating receptor represents a promising cancer immunotherapeutic target. Yet, the cellular program driven by CD137 and its role in cancer immune surveillance remain unresolved. Using T cell-specific deletion and agonist antibodies, we found that CD137 modulates tumor infiltration of CD8+-exhausted T (Tex) cells expressing PD1, Lag-3, and Tim-3 inhibitory receptors. T cell-intrinsic, TCR-independent CD137 signaling stimulated the proliferation and the terminal differentiation of Tex precursor cells through a mechanism involving the RelA and cRel canonical NF-κB subunits and Tox-dependent chromatin remodeling. While Tex cell accumulation induced by prophylactic CD137 agonists favored tumor growth, anti-PD1 efficacy was improved with subsequent CD137 stimulation in pre-clinical mouse models. Better understanding of T cell exhaustion has crucial implications for the treatment of cancer and infectious diseases. Our results identify CD137 as a critical regulator of Tex cell expansion and differentiation that holds potential for broad therapeutic applications.

Checkpoint blockade meets gene therapy: Opportunities to improve response and reduce toxicity

Immune checkpoint inhibitors (ICIs) based on monoclonal antibodies represent a breakthrough for the treatment of cancer. However, their efficacy varies among tumor types and patients, and they can lead to adverse effects due to on-target/off-tumor activity, since they are administered systemically at high doses. An alternative and attractive approach for the delivery of ICIs is the use of gene therapy vectors able to express them in vivo. This review focuses on the most recent studies using viral vectors able to express ICIs locally or systemically in preclinical models of cancer. These vectors include non-replicating viruses, oncolytic viruses able to propagate specifically in tumor cells and destroy them, and self-amplifying RNA vectors, armed with different formats of antibodies against immune checkpoints. Non-replicating vectors usually lead to long-term ICI expression, potentially eliminating the need for repeated administration. Vectors with replication capacity, although they have a shorter window of expression, can induce inflammation which enhances the antitumor effect. Finally, these engineered vectors can be used in combination with other immunostimulatory molecules or with CAR-T cells, further boosting the antitumor immune responses.

Targeting CD137 (4-1BB) towards improved safety and efficacy for cancer immunotherapy

T cells play a critical role in antitumor immunity, where T cell activation is regulated by both inhibitory and costimulatory receptor signaling that fine-tune T cell activity during different stages of T cell immune responses. Currently, cancer immunotherapy by targeting inhibitory receptors such as CTLA-4 and PD-1/L1, and their combination by antagonist antibodies, has been well established. However, developing agonist antibodies that target costimulatory receptors such as CD28 and CD137/4-1BB has faced considerable challenges, including highly publicized adverse events. Intracellular costimulatory domains of CD28 and/or CD137/4-1BB are essential for the clinical benefits of FDA-approved chimeric antigen receptor T cell (CAR-T) therapies. The major challenge is how to decouple efficacy from toxicity by systemic immune activation. This review focuses on anti-CD137 agonist monoclonal antibodies with different IgG isotypes in clinical development. It discusses CD137 biology in the context of anti-CD137 agonist drug discovery, including the binding epitope selected for anti-CD137 agonist antibody in competition or not with CD137 ligand (CD137L), the IgG isotype of antibodies selected with an impact on crosslinking by Fc gamma receptors, and the conditional activation of anti-CD137 antibodies for safe and potent engagement with CD137 in the tumor microenvironment (TME). We discuss and compare the potential mechanisms/effects of different CD137 targeting strategies and agents under development and how rational combinations could enhance antitumor activities without amplifying the toxicity of these agonist antibodies.

Reinstating immunogenicity using bispecific anti-checkpoint/agent inhibitors

Immune checkpoint inhibitor (ICI) resistance demands for acquisition of novel strategies in order to broaden the therapeutic repertoire of advanced cancers. Bispecific antibodies can be utilized as an emerging therapeutic paradigm and a step forward in cancer immunotherapy. Synchronous inhibition of programmed death-1 (PD-1), programmed death-ligand 1 (PD-L1) or cytotoxic T lymphocyte associated antigen-4 (CTLA-4), or with other agents can expand antibody selectivity and improve therapeutic window through tightening cell-to-cell bridge (a process called immunological synapse) within tumor immune microenvironment (TIME). There is evidence of higher potency of this co-targeting approach over combined single-agent monoclonal antibodies in reinvigorating anti-tumor immune responses, retarding tumor growth, and improving patient survival. In fact, immunological synapses formed by interactions of such bispecific agents with TIME cells directly mediate cytotoxicity against tumor cells, and durable anti-tumor immune responses are predictable after application of such agents. Besides, lower adverse events are reported for bispecific antibodies compared with individual checkpoint inhibitors. These are all indicative of the importance of exploiting novel bispecific approach as a replacement for conventional combo checkpoint inhibitor therapy particularly for tumors with immunosuppressive or cold immunity. Study in this area is still continued, and in the future more will be known about the importance of this bispecific approach in cancer immunotherapy.

An Fc-muted bispecific antibody targeting PD-L1 and 4-1BB induces antitumor immune activity in colorectal cancer without systemic toxicity

BACKGROUND

Resistance to immune checkpoint inhibitor (ICI) therapy narrows the efficacy of cancer immunotherapy. Although 4-1BB is a promising drug target as a costimulatory molecule of immune cells, no 4-1BB agonist has been given clinical approval because of severe liver toxicity or limited efficacy. Therefore, a safe and efficient immunostimulatory molecule is urgently needed for cancer immunotherapy.

METHODS

HK010 was generated by antibody engineering, and the Fab/antigen complex structure was analyzed using crystallography. The affinity and activity of HK010 were detected by multiple in vitro bioassays, including enzyme-linked immunosorbent assay (ELISA), surface plasmon resonance (SPR), flow cytometry, and luciferase-reporter assays. Humanized mice bearing human PD-L1-expressing MC38 (MC38/hPDL1) or CT26 (CT26/hPDL1) tumor transplants were established to assess the in vivo antitumor activity of HK010. The pharmacokinetics (PK) and toxicity of HK010 were evaluated in cynomolgus monkeys.

RESULTS

HK010 was generated as an Fc-muted immunoglobulin (Ig)G4 PD-L1x4-1BB bispecific antibody (BsAb) with a distinguished Fab/antigen complex structure, and maintained a high affinity for human PD-L1 (KD: 2.27 nM) and low affinity for human 4-1BB (KD: 493 nM) to achieve potent PD-1/PD-L1 blockade and appropriate 4-1BB agonism. HK010 exhibited synergistic antitumor activity by blocking the PD-1/PD-L1 signaling pathway and stimulating the 4-1BB signaling pathway simultaneously, and being strictly dependent on the PD-L1 receptor in vitro and in vivo. In particular, when the dose was decreased to 0.3 mg/kg, HK010 still showed a strong antitumor effect in a humanized mouse model bearing MC38/hPDL1 tumors. Strikingly, HK010 treatment enhanced antitumor immunity and induced durable antigen-specific immune memory to prevent rechallenged tumor growth by recruiting CD8+ T cells and other lymphocytes into tumor tissue and activating tumor-infiltrating lymphocytes. Moreover, HK010 not only did not induce nonspecific production of proinflammatory cytokines but was also observed to be well tolerated in cynomolgus monkeys in 5 week repeated-dose (5, 15, or 50 mg/kg) and single-dose (75 or 150 mg/kg) toxicity studies.

CONCLUSION

We generated an Fc-muted anti-PD-L1x4-1BB BsAb, HK010, with a distinguished structural interaction with PD-L1 and 4-1BB that exhibits a synergistic antitumor effect by blocking the PD-1/PD-L1 signaling pathway and stimulating the 4-1BB signaling pathway simultaneously. It is strictly dependent on the PD-L1 receptor with no systemic toxicity, which may offer a new option for cancer immunotherapy.

A bispecific antibody AP203 targeting PD-L1 and CD137 exerts potent antitumor activity without toxicity

BACKGROUND

Bispecific antibody has garnered considerable attention in the recent years due to its impressive preliminary efficacy in hematological malignancies. For solid tumors, however, the main hindrance is the suppressive tumor microenvironment, which effectively impedes the activation of infiltrating T cells. Herein, we designed a bispecific antibody AP203 with high binding affinity to PD-L1 and CD137 and assessed its safety and anti-tumor efficacy, as well as explored the mechanism of action.

METHODS

The optimal antibody binders against PD-L1 and CD137 were screened from the OmniMab phagemid library. The binding affinity of the constructed AP203 were evaluated using enzyme-linked immunosorbent assay (ELISA) and biolayer interferometry (BLI). T-cell stimulatory capacity was assessed using the allogeneic mixed lymphocyte reaction (MLR), antigen-specific recall response, and coculture with PD-L1-expressing cells. In vivo antitumor efficacy was evaluated using two models of tumor-xenografted humanized mice with profiling of tumor infiltrating lymphocytes (TILs). The possible toxicity of AP203 was examined using in vitro cytokine release assay by human PBMCs.

RESULTS

AP203, which simultaneously targeted PD-L1 and costimulatory CD137, elicit superior agonistic effects over parental antibodies alone or in combination in terms of T cell activation, enhanced memory recall responses, and overcoming Treg-mediated immunosuppression (P < 0.05). The agonistic activity of AP203 was further demonstrated PD-L1-dependent by coculturing T cells with PD-L1-expressing cells. In vivo animal studies using immunodeficient or immunocompetent mice both showed a dose-related antitumor efficacy superior to parental antibodies in combination (P < 0.05). Correspondingly, AP203 significantly increased tumor infiltrating CD8 + T cells, while decreased CD4 + T cells, as well as Treg cells (P < 0.05), resulting in a dose-dependent increase in the CD8 + /CD4 + ratio. Moreover, either soluble or immobilized AP203 did not induce the production of inflammatory cytokines by human PBMCs.

CONCLUSIONS

AP203 exerts potent antitumor activity not only by blocking PD-1/PD-L1 inhibitory signaling, but also by activating CD137 costimulatory signaling in effector T cells that consequently counteracts Treg-mediated immunosuppression. Based on promising preclinical results, AP203 should be a suitable candidate for clinical treatment of solid tumors.

Tumor immune microenvironment (TIME) to enhance antitumor immunity

The tumor microenvironment is a result of dynamic interaction between different cellular and non-cellular components. In its essence it is not a solo performer, but an ensemble of performers that includes cancer cells, fibroblasts, myo-fibroblasts, endothelial cells and immune cells. The short review highlights important immune infiltrates within the tumor microenvironment that shape cytotoxic t lymphocyte (CTL)-rich immune hot and CTL-deficient immune cold tumors and novel strategies that have potential role in enhancing our immune responses in both immune hot and immune cold tumors.

Mechanisms of CD8+ T cell exclusion and dysfunction in cancer resistance to anti-PD-(L)1

CD8⁺ T cells are the front-line defensive cells against cancer. Reduced infiltration and effector function of CD8⁺ T cells occurs in cancer and is contributed to defective immunity and immunotherapy resistance. Exclusion and exhaustion of CD8⁺ T cells are the two key factors associated with reduced durability of immune checkpoint inhibitor (ICI) therapy. Initially activated T cells upon exposure to chronic antigen stimulation or immunosuppressive tumor microenvironment (TME) acquire a hyporesponsive state that progressively lose their effector function. Thus, a key strategy in cancer immunotherapy is to look for factors contributed to defective CD8⁺ T cell infiltration and function. Targeting such factors can define a promising supplementary approach in patients receiving anti-programmed death-1 receptor (PD-1)/anti-programmed death-ligand 1 (PD-L1) therapy. Recently, bispecific antibodies are developed against PD-(L)1 and a dominant factor within TME, representing higher safety profile and exerting more desired outcomes. The focus of this review is to discuss about promoters of deficient infiltration and effector function of CD8⁺ T cells and their addressing in cancer ICI therapy.

Preclinical and Basic Research Strategies for Overcoming Resistance to Targeted Therapies in HER2-Positive Breast Cancer

The amplification of epidermal growth factor receptor 2 (HER2) is associated with a poor prognosis and HER2 gene is overexpressed in approximately 15-30% of breast cancers. In HER2-positive breast cancer patients, HER2-targeted therapies improved clinical outcomes and survival rates. However, drug resistance to anti-HER2 drugs is almost unavoidable, leaving some patients with an unmet need for better prognoses. Therefore, exploring strategies to delay or revert drug resistance is urgent. In recent years, new targets and regimens have emerged continuously. This review discusses the fundamental mechanisms of drug resistance in the targeted therapies of HER2-positive breast cancer and summarizes recent research progress in this field, including preclinical and basic research studies.

The Regulatory Axis of PD-L1 Isoform 2/TNF/T Cell Proliferation Is Required for the Canonical Immune-Suppressive Effects of PD-L1 Isoform 1 in Liver Cancer

Despite the well-studied effects of the full-length membrane-locating isoform Iso1 of Programmed Cell Death Protein-Ligand 1 (PD-L1) on immunosuppression, little is known about another membrane-locating isoform, Iso2. While expressional and survival analysis of liver cancer patients indicated that Iso2 plays a tumor-suppressive role, our results also indicated that the tumor-promoting and immune-suppressive effects of Iso1 depended on the positive expression of Iso2. Through mediation analysis, we discovered several downstream genes or pathways of Iso2 and investigated their effects on the Iso1-regulating survival. Among all potential downstream immune factors, Iso2 was inclined to activate the proliferation of T cells by regulating chemokine activity and increasing CD3 levels by promoting TNF expression. Similar results were confirmed in the Mongolian liver cancer cohort, and the Iso2/TNF/T-cell axis was verified in several other cancers in the TCGA cohort. Finally, we demonstrated the promoting effects of Iso2 in terms of producing TNF and increasing T cells both in vitro and in vivo. Our findings illustrate that PD-L1 Iso2 can increase the number of T cells in the tumor microenvironment by elevating TNF levels, which is a necessary part of the tumor-suppressive effects of Iso1 in liver cancer.

CD137 (4-1BB)-Based Cancer Immunotherapy on Its 25th Anniversary

Twenty-five years ago, we reported that agonist anti-CD137 monoclonal antibodies eradicated transplanted mouse tumors because of enhanced CD8+ T-cell antitumor immunity. Mouse models indicated that anti-CD137 agonist antibodies synergized with various other therapies. In the clinic, the agonist antibody urelumab showed evidence for single-agent activity against melanoma and non-Hodgkin lymphoma but caused severe liver inflammation in a fraction of the patients. CD137's signaling domain is included in approved chimeric antigen receptors conferring persistence and efficacy. A new wave of CD137 agonists targeting tumors, mainly based on bispecific constructs, are in early-phase trials and are showing promising safety and clinical activity.

SIGNIFICANCE

CD137 (4-1BB) is a costimulatory receptor of T and natural killer lymphocytes whose activity can be exploited in cancer immunotherapy strategies as discovered 25 years ago. Following initial attempts that met unacceptable toxicity, new waves of constructs acting agonistically on CD137 are being developed in patients, offering signs of clinical and pharmacodynamic activity with tolerable safety profiles.

Advanced development of biomarkers for immunotherapy in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common liver cancer and one of the leading causes of cancer-related deaths in the world. Mono-immunotherapy and combination therapy with immune checkpoint inhibitors (ICIs) and multitargeted tyrosine kinase inhibitors (TKIs) or anti-vascular endothelial growth factor (anti-VEGF) inhibitors have become new standard therapies in advanced HCC (aHCC). However, the clinical benefit of these treatments is still limited. Thus, proper biomarkers which can predict treatment response to immunotherapy to maximize clinical benefit while sparing unnecessary toxicity are urgently needed. Contrary to other malignancies, up until now, no acknowledged biomarkers are available to predict resistance or response to immunotherapy for HCC patients. Furthermore, biomarkers, which are established in other cancer types, such as programmed death ligand 1 (PD-L1) expression and tumor mutational burden (TMB), have no stable predictive effect in HCC. Thus, plenty of research focusing on biomarkers for HCC is under exploration. In this review, we summarize the predictive and prognostic biomarkers as well as the potential predictive mechanism in order to guide future research direction for biomarker exploration and clinical treatment options in HCC.

The Bispecific Tumor Antigen-Conditional 4-1BB x 5T4 Agonist, ALG.APV-527, Mediates Strong T-Cell Activation and Potent Antitumor Activity in Preclinical Studies

4-1BB (CD137) is an activation-induced costimulatory receptor that regulates immune responses of activated CD8 T and natural killer cells, by enhancing proliferation, survival, cytolytic activity, and IFNγ production. The ability to induce potent antitumor activity by stimulating 4-1BB on tumor-specific cytotoxic T cells makes 4-1BB an attractive target for designing novel immuno-oncology therapeutics. To minimize systemic immune toxicities and enhance activity at the tumor site, we have developed a novel bispecific antibody that stimulates 4-1BB function when co-engaged with the tumor-associated antigen 5T4. ALG.APV-527 was built on the basis of the ADAPTIR bispecific platform with optimized binding domains to 4-1BB and 5T4 originating from the ALLIGATOR-GOLD human single-chain variable fragment library. The epitope of ALG.APV-527 was determined to be located at domain 1 and 2 on 4-1BB using X-ray crystallography. As shown in reporter and primary cell assays in vitro, ALG.APV-527 triggers dose-dependent 4-1BB activity mediated only by 5T4 crosslinking. In vivo, ALG.APV-527 demonstrates robust antitumor responses, by inhibiting growth of established tumors expressing human 5T4 followed by a long-lasting memory immune response. ALG.APV-527 has an antibody-like half-life in cynomolgus macaques and was well tolerated at 50.5 mg/kg. ALG.APV-527 is uniquely designed for 5T4-conditional 4-1BB-mediated antitumor activity with potential to minimize systemic immune activation and hepatotoxicity while providing efficacious tumor-specific responses in a range of 5T4-expressing tumor indications as shown by robust activity in preclinical in vitro and in vivo models. On the basis of the combined preclinical dataset, ALG.APV-527 has potential as a promising anticancer therapeutic for the treatment of 5T4-expressing tumors.

Antibodies as drugs-a Keystone Symposia report

Therapeutic antibodies have broad indications across diverse disease states, such as oncology, autoimmune diseases, and infectious diseases. New research continues to identify antibodies with therapeutic potential as well as methods to improve upon endogenous antibodies and to design antibodies de novo. On April 27-30, 2022, experts in antibody research across academia and industry met for the Keystone symposium "Antibodies as Drugs" to present the state-of-the-art in antibody therapeutics, repertoires and deep learning, bispecific antibodies, and engineering.

The emerging landscape of novel 4-1BB (CD137) agonistic drugs for cancer immunotherapy

The clinical development of 4-1BB agonists for cancer immunotherapy has raised substantial interest during the past decade. The first generation of 4-1BB agonistic antibodies entering the clinic, urelumab (BMS-663513) and utomilumab (PF-05082566), failed due to (liver) toxicity or lack of efficacy, respectively. The two antibodies display differences in the affinity and the 4-1BB receptor epitope recognition, as well as the isotype, which determines the Fc-gamma-receptor (FcγR) crosslinking activity. Based on this experience a very diverse landscape of second-generation 4-1BB agonists addressing the liabilities of first-generation agonists has recently been developed, with many entering clinical Phase 1 and 2 studies. This review provides an overview focusing on differences and their scientific rationale, as well as challenges foreseen during the clinical development of these molecules.

Immune Checkpoint Inhibitor-Based Combination Therapy for Colorectal Cancer: An Overview

Colorectal cancer (CRC) is one of the most common diseases in the world. Tumor immunotherapy is an innovative cancer treatment that acts by activating the human body's autoimmune system. Immune checkpoint block has been shown to be effective in DNA deficient mismatch repair/microsatellite instability-high CRC. However, the therapeutic effect for proficient mismatch repair/microsatellite stability patients still requires further study and optimization. At present, the main CRC strategy is to combine other therapeutic methods, such as chemotherapy, targeted therapy, and radiotherapy. Here, we review the current status and the latest progress of immune checkpoint inhibitors in the treatment of CRC. At the same time, we consider therapeutic opportunities for transforming cold to hot, as well as perspectives on possible future therapies, which may be in great demand for drug-resistant patients.

Prognosis and Immunological Characteristics of PGK1 in Lung Adenocarcinoma: A Systematic Analysis

Background: Aerobic glycolysis plays a key role in tumor metabolic reprogramming to reshape the immune microenvironment. The phosphoglycerate kinase 1 (PGK1) gene codes a glycolytic enzyme that converts 1,3-diphosphoglycerate to 3-phosphoglycerate. However, in lung adenocarcinoma (LUAD), the role of PGK1 in altering the tumor microenvironment (TME) has not yet been determined. Methods: Raw data, including bulk DNA and mRNA-seq data, methylation modification data, single-cell RNA-seq data, proteomics data, clinical case characteristics survival, immunotherapy data, and so on, were obtained from multiple independent public data sets. These data were reanalyzed to uncover the prognosis and immunological characteristics of PGK1 in LUAD. Results: We found that PGK1 mRNA and protein were considerably over-expressed in LUAD compared to normal tissue and that high PGK1 expression is associated with poorer prognostic outcomes in LUAD. The enrichment analysis of PGK1 co-expressed genes in lung adenocarcinoma revealed that PGK1 may be involved in hypoxia, metabolism, DNA synthesis, cell cycle, PI3K/AKT, and various immune and inflammatory signaling pathways. Furthermore, PGK1 is also linked to the recruitment of numerous immune cells, including aDC (dendritic cells), macrophages, and neutrophils. More importantly, PGK1 was highly expressed in immunosuppressive cells, including M2 macrophages, Tregs, and exhausted T cells, among others. Finally, higher PGK1 expression indicated significant correlations to immune checkpoints, TMB (tumor mutation burden), and high response to immunotherapy. Conclusions: The presented findings imply that PGK1, as a glycolysis core gene, may be important for the modification of the immune microenvironment by interacting with the tumor metabolism. The results of this study provide clues for a potential immunometabolic combination therapy strategy in LUAD, for which more experimental and clinical translational research is needed.

Serum Concentration of CD137 and Tumor Infiltration by M1 Macrophages Predict the Response to Sintilimab plus Bevacizumab Biosimilar in Advanced Hepatocellular Carcinoma Patients

PURPOSE

This study aimed to investigate the biomarkers of sintilimab (anti-PD-1) plus IBI305 (a bevacizumab biosimilar) in advanced hepatocellular carcinoma (HCC), as well as their safety and efficacy.

PATIENTS AND METHODS

A total of 50 patients with advanced HCC received sintilimab (200 mg) plus IBI305 (7.5 or 15 mg/kg), treated every 3 weeks in a phase Ib clinical study. We performed baseline serum cytokine analysis using bead-based multiplex immunoassay and multiplex immunofluorescence on tissue specimens to discover novel biomarkers of response to VEGF/PD-1 combination therapy in HCC.

RESULTS

The overall response rate was 34.0% (17/50). The median progression-free survival (PFS) and the median overall survival were 10.5 and 20.2 months, respectively. The incidence of grade 3 to 5 adverse events was lower in the 7.5 mg/kg (13.8%) than in the 15 mg/kg (28.6%) dose groups. Biomarker analysis showed that the serum CD137 concentration was significantly higher in patients with clinical benefit (CB) than in those without CB (median, 32.8 pg/mL vs. 19.8 pg/mL, P = 0.034). A markedly longer PFS was observed in patients with high CD137 concentrations compared with those with low concentrations (median, 14.2 months vs. 4.1 months, P = 0.001). The higher density of M1 macrophages (CD68+CD163-) in the stroma was also associated with higher efficacy (P = 0.033) and a longer PFS (P = 0.024).

CONCLUSIONS

Sintilimab plus IBI305 was well tolerated and was effective therapy for advanced HCC. Both serum concentrations of CD137 and tumor infiltration of M1 macrophages may serve as potential predictive biomarkers. See related commentary by Cappuyns and Llovet, p. 3405.

Mapping the single-cell landscape of acral melanoma and analysis of the molecular regulatory network of the tumor microenvironments

Acral melanoma (AM) exhibits a high incidence in Asian patients with melanoma, and it is not well treated with immunotherapy. However, little attention has been paid to the characteristics of the immune microenvironment in AM. Therefore, in this study, we collected clinical samples from Chinese patients with AM and conducted single-cell RNA sequencing to analyze the heterogeneity of its tumor microenvironments (TMEs) and the molecular regulatory network. Our analysis revealed that genes, such as TWIST1, EREG, TNFRSF9, and CTGF could drive the deregulation of various TME components. The molecular interaction relationships between TME cells, such as MIF-CD44 and TNFSF9-TNFRSF9, might be an attractive target for developing novel immunotherapeutic agents.

Acral melanoma is a type of cancer that affects the hands and feet. It tends to form on the palms, soles, and under the nails. It is rare in people of European descent, but in Asian populations it makes up more than half of all melanoma cases. Unlike other types of skin cancer, it does not respond well to immunotherapy, but scientists did not understand why.

Historically, cancer research has focused on the genetics of whole tumors. But cancer is complicated. Malignant cells recruit other cells to help them survive and grow, and to protect them from attacks by the immune system. Together, they create their own ecosystem, called the tumor microenvironment. The exact makeup of the tumor microenvironment differs depending on the type of cancer and on the genetics of the individual. Investigating the cells that ‘support’ the tumor could help to explain how acral melanoma develops and why it does not respond to treatment.

To address these questions, He et al. collected samples from six patients with acral melanoma and examined the genes used by more than 60,000 individual cells. This revealed nine different types of cells in the tumor microenvironment. Most were cancer cells, but there were also immune cells, blood vessel cells, skin cells, and a type of cell that makes connective tissue. He et al. also identified four genes that most likely shape the tumor microenvironment, and two gene pairs that may control some of the interactions between the cells.

Investigating these early findings in more detail could open new treatment avenues for acral melanoma. The number of samples in this study was small, but it provides a starting point for future investigation. With more data, researchers could start to develop treatments that target the unique tumor microenvironment of this type of cancer.

The prognostic value and immune landscape of a cuproptosis-related lncRNA signature in head and neck squamous cell carcinoma

Background: Cuproptosis has been recognized as a novel regulatory cell death, which has been confirmed to promote the occurrence and development of tumors. However, whether cuproptosis-related lncRNA has an impact on the prognosis of squamous cell carcinoma of the head and neck (HNSCC) is still unclear.

Methods: In total, 501 HNSCC tumor samples and 44 normal were downloaded from the TCGA database. Cuproptosis-related lncRNAs were obtained by co-expressed analysis. We got prognostic lncRNA that was associated with cuproptosis by using univariate Cox regression analysis and LASSO Cox regression. Then we constructed and validated the prognostic signature of HNSCC and analyzed the immune landscape of the signature.

Results: The Prognostic Signature is based on 10 cuproptosis-related lncRNAs including AC090587.1, AC004943.2, TTN-AS1, AL162458.1, AC106820.5, AC012313.5, AL132800.1, WDFY3-AS2, CDKN2A-DT, and AL136419.3. The results of overall survival, risk score distribution, and survival status in the low-risk group were better than those in the high-risk group. In addition, all immune checkpoint genes involved were significantly different between the two risk groups (p < 0.05). The risk score was positively correlated with Eosinophils. M0 and M2 phenotype macrophages, mast cells activated, NK cells activated, and negatively related with B cells naive, mast cells resting, plasma cells, CD8T cells, T cells follicular helper, T cells regulatory (Tregs). Consensus clustering was identified in molecular subtypes of HNSC. More high-risk samples concentrated in Cluster1, which had a higher Tumor Immune Dysfunction and Exclusion (TIDE) score and Single Nucleotide Polymorphisms (SNP) alternation than Cluster2.

Conclusion: Our study elucidated the correlation between cuproptosis-related lncRNA with prognosis and immune landscape of HNSCC, which may provide references for further research on the exploration of the mechanism and functions of the prognosis for HNSCC.