Targeting Immune Checkpoints Research Articles

Lymphocyte Activation Gene 3 Expression, γδ T-Cell/Major Histocompatibility Complex Class I Interactions, and Prognosis in Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is an aggressive cutaneous malignancy with a poor prognosis. One of the major mechanisms of immune evasion in MCC involves downregulation of major histocompatibility complex class I (MHC-I). Anti-PD-1/programmed death ligand 1 checkpoint inhibitors have revolutionized treatment for MCC, producing objective responses in approximately 50% of patients, and are now the standard of care; however, a substantial proportion of patients either fail to respond or develop resistance to checkpoint inhibitors. Given these recent successes, identification of other targetable immune checkpoints in the MCC tumor microenvironment is of great interest. Additionally, γδ T cells may play critical roles in response to MHC-I–deficient cancers; therefore, evaluating γδ T cells as a prognostic biomarker is warranted. We characterized the expression of programmed death ligand 1, PD-1, CD3, CD8, lymphocyte activation gene 3 (LAG-3), MHC-I, and γδ T cells by immunohistochemistry in a preimmunotherapy retrospective cohort of 54 cases of MCC and quantified expression levels and marker density using HALO software. The increased density of LAG-3 and γδ T cells correlated with other markers of an inflamed tumor microenvironment, with significant positive associations across all 6 markers (P < .002). Reflective of their putative role in the response to MHC-I–suppressed cancers, cases with low human leukocyte antigen I density showed a trend toward a higher ratio of γδ T cells:CD3+ T cells (Spearman r = −0.1582; P = .21). Importantly, high CD3 density (hazard ratio [HR], 0.23; P = .002), LAG-3 density (HR, 0.47; P = .037), γδ T-cell density (HR, 0.26; P = .02), and CD8 density (HR, 0.27; P = .03) showed associations with improved progression-free survival. Conditional tree analysis demonstrated that high CD8 and TCRδ expression were nonsignificant predictors of improved progression-free survival and overall survival. Overall, LAG-3 is expressed in MCC infiltrates and is prognostic in preimmunotherapy MCC, suggesting a potential role for LAG-3 inhibition in MCC. Additionally, CD8 and γδ T cells may play a critical role in the response to MCC, and γδ T-cell density may represent a novel biomarker in MCC.

Is modulation of immune checkpoints on glioblastoma-infiltrating myeloid cells a viable therapeutic strategy?

The field of immunology has traditionally focused on immune checkpoint modulation of adaptive immune cells. However, many malignancies such as glioblastoma are mostly devoid of T cells and rather are enriched with immunosuppressive myeloid cells of the innate immune system. While some immune checkpoint targets are shared between adaptive and innate immunity, myeloid-specific checkpoints could also serve as potential therapeutics. To better understand the impact of immune checkpoint blockade on myeloid cells, we systematically summarize the current literature focusing on the direct immunological effects of PD-L1/PD-1, CD24/Siglec-10, collagen/LAIR-1, CX3CL1/CX3CR1, and CXCL10/CXCR3. By synthesizing the molecular mechanisms and the translational implications, we aim to prioritize agents in this category of therapeutics for glioblastoma.

P1.03D.06 Targeting IL-6 And Immune Checkpoint Interactions to Augment the Anti-Tumor Immune Response in Lung Carcinoma

P1.03D.06 Targeting IL-6 And Immune Checkpoint Interactions to Augment the Anti-Tumor Immune Response in Lung Carcinoma

Advances in Understanding Hepatocellular Carcinoma Vasculature: Implications for Diagnosis, Prognostication, and Treatment.

Hepatocellular carcinoma (HCC) progresses through multiple stages of hepatocarcinogenesis, with each stage characterized by specific changes in vascular supply, drainage, and microvascular structure. These vascular changes significantly influence the imaging findings of HCC, enabling non-invasive diagnosis. Vascular changes in HCC are closely related to aggressive histological characteristics and treatment responses. Venous drainage from the tumor toward the portal vein in the surrounding liver facilitates vascular invasion, and the unique microvascular pattern of vessels that encapsulate the tumor cluster (known as a VETC pattern) promotes vascular invasion and metastasis. Systemic treatments for HCC, which are increasingly being used, primarily target angiogenesis and immune checkpoint pathways, which are closely intertwined. By understanding the complex relationship between histopathological vascular changes in hepatocarcinogenesis and their implications for imaging findings, radiologists can enhance the accuracy of imaging diagnosis and improve the prediction of prognosis and treatment response. This, in turn, will ultimately lead to better patient care.

Emerging druggable targets for immune checkpoint modulation in cancer immunotherapy: the iceberg lies beneath the surface.

The immune system serves as a fundamental defender against the initiation and progression of cancer. Failure of the immune system augments immunosuppressive action that leading to cancer manifestation. This immunosuppressive effect causes from significant alterations in immune checkpoint expression associated with tumoral progression. The tumor microenvironment promotes immune escape mechanisms that further amplifying immunosuppressive actions. Notably, substantial targeting of immune checkpoints has been pragmatic in the advancement of cancer research. This study highlights a comprehensive review of emerging druggable targets aimed at modulating immune checkpoint co-inhibitory as well as co-stimulatory molecules in response to immune system activation. This modulation has prompted to the development of newer therapeutic insights, eventually inducing immunogenic cell death through immunomodulatory actions. The study emphasizes the role of immune checkpoints in immunogenic regulation of cancer pathogenesis and explores potential therapeutic avenues in cancer immunotherapy.Modulation of Immunosuppressive and Immunostimulatory pathways of immune checkpoints in cancer immunotherapy.

Yap methylation-induced FGL1 expression suppresses anti-tumor immunity and promotes tumor progression in KRAS-driven lung adenocarcinoma.

Despite significant strides in lung cancer immunotherapy, the response rates for Kirsten rat sarcoma viral oncogene homolog (KRAS)-driven lung adenocarcinoma (LUAD) patients remain limited. Fibrinogen-like protein 1 (FGL1) is a newly identified immune checkpoint target, and the study of related resistance mechanisms is crucial for improving the treatment outcomes of LUAD patients. This study aimed to elucidate the potential mechanism by which FGL1 regulates the tumor microenvironment in KRAS-mutated cancer. The expression levels of FGL1 and SET1 histone methyltransferase (SET1A) in lung cancer were assessed using public databases and clinical samples. Lentiviruses were constructed for transduction to overexpress or silence FGL1 in lung cancer cells and mouse models. The effects of FGL1 and Yes-associated protein (Yap) on the immunoreactivity of cytotoxic T cells in tumor tissues were evaluated using immunofluorescence staining and flow cytometry. Chromatin immunoprecipitation and dual luciferase reporter assays were used to study the SET1A-directed transcriptional program. Upregulation of FGL1 expression in KRAS-mutated cancer was inversely correlated with the infiltration of CD8+ T cells. Mechanistically, KRAS activated extracellular signal-regulated kinase 1/2 (ERK1/2), which subsequently phosphorylated SET1A and increased its stability and nuclear localization. SET1A-mediated methylation of Yap led to Yap sequestration in the nucleus, thereby promoting Yap-induced transcription of FGL1 and immune evasion in KRAS-driven LUAD. Notably, dual blockade of programmed cell death-1 (PD-1) and FGL1 further increased the therapeutic efficacy of anti-PD-1 immunotherapy in LUAD patients. FGL1 could be used as a diagnostic biomarker of KRAS-mutated lung cancer, and targeting the Yap-FGL1 axis could increase the efficacy of anti-PD-1 immunotherapy.

Higher frequency of peripheral blood CD103+CD8+ T cells with lower levels of PD-1 and TIGIT expression related to favorable outcomes in leukemia patients.

Leukemia is a prevalent pediatric life-threatening hematologic malignancy with a poor prognosis. Targeting immune checkpoints (ICs) to reverse T cell exhaustion is a potentially effective treatment for leukemia. Tissue resident memory T (TRM) cells have been found to predict the efficacy of programmed death receptor-1 inhibitor (anti-PD-1) therapy in solid tumors. However, the IC characteristics of TRM cells in leukemia and their relationship with prognosis remain unclear. We employed multi-color flow cytometry to evaluate the frequencies of CD103+CD4+ and CD103+CD8+ T cells in the peripheral blood (PB) of patients with acute myeloid leukemia and B-cell acute lymphoblastic leukemia compared to healthy individuals. We examined the expression patterns of PD-1 and T cell immunoreceptor with immunoglobulin and ITIM domain (TIGIT) within the circulating CD103+ T cell subsets affected by leukemia. To further elucidate the immunological landscape, we assessed the differentiation status of CD103+ T cells across various disease states in patients with leukemia. Our findings showed a significant increase in the frequency of CD103+CD8+ T cells in the PB of patients with leukemia who had achieved complete remission (CR) compared to those in the de novo (DN) and relapsed/refractory (RR) stages. This increase was accompanied by a notable decrease in the expression levels of PD-1 and TIGIT in CD103+CD8+ T cells in the CR stage. Additionally, our analysis revealed a higher proportion of CD103+CD8+ T cells in the central memory (TCM) and effector memory (TEM) subsets of the immune profile. Notably, the proportions of CD103+ naïve T cells, CD103+ TEM, and CD103+ terminally differentiated T cells within the CD8+ T cell population were significantly elevated in patients with CR compared to those in the DN/RR stages. The data indicate that circulating higher frequency of CD103+CD8+ T cells with lower expression of PD-1 and TIGIT are associated with favorable outcomes in patients with leukemia. This suggests a potential role of TRM cells in leukemia prognosis and provides a foundation for developing targeted immunotherapies.

Therapeutic vaccine targeting dual immune checkpoints induces potent multifunctional CD8+ T cell anti-tumor immunity

BackgroundVaccines targeting immune checkpoints represent a promising immunotherapeutic approach for solid tumors. However, the therapeutic efficacy of dual targeting immune checkpoints is still unclear in renal carcinoma. MethodsAn adenovirus (Ad) vaccine targeting B7H1 and B7H3 was developed and evaluated for its therapeutic efficacy in subcutaneous, lung metastasis or orthotopic renal carcinoma mouse and humanized models using flow cytometry, Enzyme-linked immunosorbent spot (ELISPOT), cytotoxic T lymphocyte (CTL) killing, cell deletion, hematoxylin and eosin (HE) staining, and immunohistochemistry (IHC) assays. ResultsThe Ad-B7H1/B7H3 immunization effectively inhibited tumor growth and increased the induction and percentages of CD8+ T cells in subcutaneous tumor models. The vaccine enhanced the induction and maturation of CD11c+ or CD8+CD11c+ cells, promoting tumor-specific CD8+ T cell immune responses. This was evidenced by increased proliferation of CD8+ T cells and enhanced CTL killing activity. Deletion of CD8+ T cells in vivo abolished the anti-tumor effect of the Ad-B7H1/B7H3 vaccine, highlighting the pivotal role of functional CD8+ T cell immune responses. Moreover, significant therapeutic efficacy of the Ad-B7H1/B7H3 vaccine was observed in lung metastasis, orthotopic, and humanized tumor models through multifunctional CD8+ T cell immune responses. ConclusionsThe Ad vaccine targeting dual immune checkpoints B7H1 and B7H3 exerts a potent therapeutic effect for renal carcinoma and holds promise for solid tumor treatment.

Neratinib Alone or in Combination with Immune Checkpoint Inhibitors with or without Mammalian Target of Rapamycin Inhibitors in Patients with Fibrolamellar Carcinoma

&lt;b&gt;&lt;i&gt;Introduction:&lt;/i&gt;&lt;/b&gt; Fibrolamellar carcinoma (FLC) displays upregulation of several oncogenes, including &lt;i&gt;HER2&lt;/i&gt;, and multiple immune-suppressive mechanisms. We investigated the efficacy and safety of the pan-HER tyrosine kinase inhibitor neratinib as monotherapy (SUMMIT phase 2 basket study) or with immune checkpoint and/or mammalian target of rapamycin (mTOR) inhibitors (compassionate-use program) in patients with FLC. &lt;b&gt;&lt;i&gt;Methods:&lt;/i&gt;&lt;/b&gt; Patients received neratinib 240 mg/day orally in SUMMIT, or as doublet or triplet combinations with pembrolizumab 2 mg/kg intravenously every 3 weeks, nivolumab 240 mg intravenously every 2 weeks, everolimus 7.5 mg/day orally, or sunitinib 37.5 mg/day orally under compassionate use. The primary endpoint in SUMMIT was objective response rate; safety was a secondary endpoint. &lt;b&gt;&lt;i&gt;Results:&lt;/i&gt;&lt;/b&gt; Fifteen patients with FLC received neratinib monotherapy in SUMMIT. The objective response rate was 5% (95% confidence interval [CI]: 0–21.8) and the disease control rate was 13.3% (95% CI: 1.7–40.5). Upon progression, five had added immune checkpoint inhibitors with or without everolimus or sunitinib. Two additional patients received neratinib-based combinations outside of SUMMIT, for a total of 17 neratinib-treated patients. One patient who received neratinib plus pembrolizumab had a confirmed partial response, one treated with neratinib plus everolimus had stable disease lasting 6 months, and one who received neratinib plus pembrolizumab plus sunitinib had stable disease lasting 16 months. Grade 3/4 adverse events with neratinib monotherapy occurred in 10 (66.7%)/2 (13.3%) patients, respectively. Grade 3 adverse events with neratinib-based combinations were hyperglycemia (&lt;i&gt;n&lt;/i&gt; = 1; neratinib plus pembrolizumab), hepatic failure, and anaphylaxis (&lt;i&gt;n&lt;/i&gt; = 1 each, neratinib plus pembrolizumab plus everolimus). There were no grade 4 adverse events with combination therapy. &lt;b&gt;&lt;i&gt;Conclusion:&lt;/i&gt;&lt;/b&gt; In patients with FLC, single-agent neratinib had limited efficacy, but clinical benefit was observed with neratinib in combination with immunotherapy and/or mTOR-targeted agents.

Soluble Tim-3 serves as a tumor prognostic marker and therapeutic target for CD8+ T cell exhaustion and anti-PD-1 resistance

Resistance to PD-1 blockade in onco-immunotherapy greatly limits its clinical application. Tcell immunoglobulin and mucin domain containing-3 (Tim-3), a promising immune checkpoint target, is cleaved by ADAM10/17 to produce its soluble form (sTim-3) in humans, potentially becoming involved in anti-PD-1 resistance. Herein, serum sTim-3 upregulation was observed in non-small cell lung cancer (NSCLC) and various digestive tumors. Notably, serum sTim-3 is further upregulated in non-responding patients undergoing anti-PD-1 therapy for NSCLC and anti-PD-1-resistant cholangiocarcinoma patients. Furthermore, sTim-3 overexpression facilitates tumor progression and confers anti-PD-1 resistance in multiple tumor mouse models. Mechanistically, sTim-3 induces terminal Tcell exhaustion and attenuates CD8+ Tcell response to PD-1 blockade through carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM-1). Moreover, the ADAM10 inhibitor GI254023X, which blocks sTim-3 production, reduces tumor progression in Tim-3 humanized mice and reverses anti-PD-1 resistance in human tumor-infiltrating lymphocytes (TILs). Overall, human sTim-3 holds great predictive and therapeutic potential in onco-immunotherapy.

Comprehensive analysis and identification of subtypes and hub genes of high immune response in lung adenocarcinoma

BackgroundThe advent of immunotherapy targeting immune checkpoints has conferred significant clinical advantages to patients with lung adenocarcinoma (LUAD); However, only a limited subset of patients exhibit responsiveness to this treatment. Consequently, there is an imperative need to stratify LUAD patients based on their response to immunotherapy and enhance the therapeutic efficacy of these treatments.MethodsThe differentially co-expressed genes associated with CD8 + T cells were identified through weighted gene co-expression network analysis (WGCNA) and the Search Tool for the Retrieval of Interacting Genes (STRING) database. These gene signatures facilitated consensus clustering for TCGA-LUAD and GEO cohorts, categorizing them into distinct immune subtypes (C1, C2, C3, and C4). The Tumor Immune Dysfunction and Exclusion (TIDE) model and Immunophenoscore (IPS) analysis were employed to assess the immunotherapy response of these subtypes. Additionally, the impact of inhibitors targeting five hub genes on the interaction between CD8 + T cells and LUAD cells was evaluated using CCK8 and EDU assays. To ascertain the effects of these inhibitors on immune checkpoint genes and the cytotoxicity mediated by CD8 + T cells, flow cytometry, qPCR, and ELISA methods were utilized.ResultsAmong the identified immune subtypes, subtypes C1 and C3 were characterized by an abundance of immune components and enhanced immunogenicity. Notably, both C1 and C3 exhibited higher T cell dysfunction scores and elevated expression of immune checkpoint genes. Multi-cohort analysis of Lung Adenocarcinoma (LUAD) suggested that these subtypes might elicit superior responses to immunotherapy and chemotherapy. In vitro experiments involved co-culturing LUAD cells with CD8 + T cells and implementing the inhibition of five pivotal genes to assess their function. The inhibition of these genes mitigated the immunosuppression on CD8 + T cells, reduced the levels of PD1 and PD-L1, and promoted the secretion of IFN-γ and IL-2.ConclusionsCollectively, this study delineated LUAD into four distinct subtypes and identified five hub genes correlated with CD8 + T cell activity. It lays the groundwork for refining personalized therapy and immunotherapy strategies for patients with LUAD.

The role of immune checkpoint inhibitors: Variable number of tandem repeat (VNTR) polymorphism in the second exon of the P-selectin glycoprotein ligand-1 (PSGL-1) gene polymorphism in multiple myeloma.

Somatic mutations and polymorphisms may play a role in multiple myeloma (MM) susceptibility and survival. One of the immune checkpoint inhibitors is P-selectin glycoprotein ligand-1 (PSGL-1); the majority of tumor-infiltrating leukocytes express PSGL-1, causing T cell and immune inhibition via PSGL-1 mediator molecules. We aimed to investigate the effect of variable number of tandem repeat (VNTR) polymorphism in the second exon of the PSGL-1 gene on MM susceptibility, response to treatment and survival in our patient group. A total of 238 patients diagnosed with MM between January 2010 and January 2021 and 162 healthy individuals as a control group were included in this cross-sectional study. The genotypes of the VNTR polymorphism in the second exon of the PSGL-1 gene were statistically compared between patients and healthy controls; the statistically significant effects of the genotypes on response to first-line treatment and survival were examined. The AC genotype was significantly higher in healthy controls compared to patients diagnosed with MM (p < 0.001). The median PFS in patients with AA/AB/AC was 56 months, while it was 100 months in patients with BB/CC. The hazard ratio of 1.34 for PFS was found to be clinically significant and having the BB/CC genotype could provide a longer PFS compared to others, but it was not statistically significant due to the sample size. Our study results will shed light on new study plans in terms of immune checkpoint target therapies among conventional treatment preferences in MM.

Combination therapy of targeting CD20 antibody and immune checkpoint inhibitor may be a breakthrough in the treatment of B-cell lymphoma

BackgroundCD20 is a membrane protein extensively expressed on the surface of B cells at various stages of development and differentiation. Herein, we conducted a bibliometrics analysis of the literature on CD20-targeting antibody therapy in lymphoma. MethodsA total of 6663 articles were downloaded from the web of science core collection (WOSCC) from 1999 to July 23, 2022. Bibliometric.com was used for citation and annual publications analysis. VOSviewer was used to map countries/institutions/authors/journals nodes and links, extract hotspot keywords, and analyze the time trend of keywords. Citespace was employed to recognize the turning points based on the centrality value of countries, define the topic distribution of academics according to the map of dual-map overlay of journals, and characterize the emerging topics or landmark articles in a field based on references citation bursts. ResultsAll articles were cited 225,032 times, averaging 33.77. The number of articles increased from 1999 to 2002, while the growth rate entered the platform after 2002. The USA was the most publication country, and China was the largest emerging country. Hotspots in this field still focus on the efficacy of rituximab in treating non-Hodgkin's lymphoma and the pathogenesis of lymphoma Application of generation CD-20 antibodies or molecule inhibitors in clinical research and cellular therapy/immunotherapy, such as CAR-T and PDL1/PD1 were the emerging research topics. ConclusionThis study provides essential information and the tendency of the CD20-targeting antibody therapy in lymphoma by using bibliometric and visual methods, which would provide helpful references for clinical experiments and basic scientific research.

Chemotherapy-induced high expression of IL23A enhances efficacy of anti-PD-1 therapy in TNBC by co-activating the PI3K-AKT signaling pathway of CTLs

Treatment of advanced triple-negative breast cancer (TNBC) is a great challenge in clinical practice. The immune checkpoints are a category of immunosuppressive molecules that cancer could hijack and impede anti-tumor immunity. Targeting immune checkpoints, such as anti-programmed cell death 1 (PD-1) therapy, is a promising therapeutic strategy in TNBC. The efficacy and safety of PD-1 monoclonal antibody (mAb) with chemotherapy have been validated in TNBC patients. However, the precise mechanisms underlying the synergistic effect of chemotherapy and anti-PD-1 therapy have not been elucidated, causing the TNBC patients that might benefit from this combination regimen not to be well selected. In the present work, we found that IL-23, an immunological cytokine, is significantly upregulated after chemotherapy in TNBC cells and plays a vital role in enhancing the anti-tumor immune response of cytotoxic T cells (CTLs), especially in combination with PD-1 mAb. In addition, the combination of IL-23 and PD-1 mAb could synergistically inhibit the expression of Phosphoinositide-3-Kinase Regulatory Subunit 1 (PIK3R1), which is a regulatory subunit of PI3K and inhibit p110 activity, and promote phosphorylation of AKT in TNBC-specific CTLs. Our findings might provide a molecular marker that could be used to predict the effects of combination chemotherapy therapy and PD-1 mAb in TNBC.

Exclusion of PD-1 from the immune synapse: A novel strategy to modulate T cell function

Targeting immune checkpoint receptors on T cells is a common cancer treatment strategy. Frequently, this is accomplished through antibodies targeting the ligand of inhibitory co-receptors. Blocking the immune checkpoint PD-1 binding to its ligands PD-L1 and PD-L2 prevents downstream signaling and enhances anti-tumor T cell responses. This approach improved cancer patients’ outcomes. However, only one-third of the patients respond to these treatments. To better understand the mechanism of anti-PD-1 antibodies, we explored the location of PD-1 within the immune synapse. Surprisingly, we discovered that anti-PD-1 antibodies, besides blocking the interaction between PD-1 and its ligands, also removed PD-1 from the synapse. We demonstrated a correlation between removing PD-1 from the synapse by anti-PD-1 antibodies and the extent of T cell activation.

Synthesis and Characterization of a Novel PET Tracer for Noninvasive Evaluation of FGL1 Status in Tumors.

Fibrinogen-like protein 1 (FGL1) is a potential novel immune checkpoint target for malignant tumor diagnosis and therapy. Accurate detection of FGL1 levels in tumors via noninvasive PET imaging might be beneficial for managing the disease. To achieve this, multiple FGL1-targeting peptides (FGLP) were designed, and a promising candidate, 68Ga-NOTA-FGLP2, was identified through a high-throughput screening approach using microPET imaging of 68Ga-labeled peptides. Subsequent in vitro cell experiments showed that uptake values of 68Ga-NOTA-FGLP2 in FGL1 positive Huh7 tumor cells were significantly higher than those in FGL1 negative U87 MG tumor cells. Further microPET imaging showed that the Huh7 xenografts were clearly visualized with a favorable contrast. ROI analysis showed that the uptake values of the tracer in Huh7 xenografts were 2.63 ± 0.07% ID/g at 30 min p.i.. After treatment with an excess of unlabeled FGLP2, the tumor uptake significantly decreased to 0.54 ± 0.05% ID/g at 30 min p.i.. Moreover, the uptake in U87 MG xenografts was 0.44 ± 0.06% ID/g at the same time point. The tracer was excreted mainly through the renal system. 18F-FDG PET imaging was also performed in mice bearing Huh7 and U87 MG xenografts, respectively. However, there was no significant difference in the uptake between the tumors with different FGL1 expressions. Preclinical data indicated that 68Ga-NOTA-FGLP2 might be a suitable radiotracer for in vivo noninvasive visualization of tumors with abundant expression of FGL1. Further investigation of 68Ga-NOTA-FGLP2 for tumor diagnosis and therapy is undergoing.

High-expression of V-domain Imuunoglobulin Suppressor of T-cell Activation (VISTA) Is Correlated with Advanced Pathological Features in Patients with Pancreatic Ductal Adenocarcinoma.

V-domain Imuunoglobulin suppressor of T-cell activation (VISTA) seems a promising immune checkpoint target in cancer treatment; however, its prognostic significance in pancreatic ductal adenocarcinoma (PDAC) remains unknown. Herein, 29 fresh PDAC tissue samples were used to evaluate the mRNA expression level of VISTA by real-time polymerase chain reaction (PCR). Besides, 40 formalin-fixed paraffin-embedded PDAC tissues were collected to evaluate VISTA protein expression by immunohistochemistry. Real-time PCR indicated that high expression of VISTA was significantly correlated with advanced stages of the cancer, based on the tumor/node/metastasis (TNM) stagingand tumor cell differentiation. Immunohistochemistry results also showed significant correlation of the elevated cytoplasmic expression of VISTA with advanced TNM stages, older age of the patients and was a worsening indicator, regarding the disease-specific survival. In conclusion, we found that the expression levels of VISTA can be a potential prognostic biomarker in PDAC patients and its elevated levels are correlated with poor prognostic outcomes.

Interaction between VEGF-A and immune checkpoint targets in triple-negative breast cancer and mechanisms of immune evasion and tumor progression.

1096 Background: Immune checkpoint inhibitors (ICIs) have revolutionized the treatment triple negative breast cancer (TNBC). However, not all patients with TNBC benefit from the addition of ICIs due to factors such as intrinsic and acquired resistance to ICIs, and complex interplay between tumor and immune cells in the tumor microenvironment (TME). Vascular endothelial growth factor (VEGF) promotes angiogenesis and potentially modulates tumor immune evasion. A phase I clinical trial has shown that a bispecific antibody to VEGF-A and PD-L1 produces encouraging tumor responses in advanced TNBC. In this study, we investigated the interaction between VEGF and various immune gene expression signatures including PD-L1 in a real-world breast cancer patient population. Methods: Comprehensive immune profiling, including the RNA-seq based gene expression assessment of 395 immune-associated genes, was performed on 120 formalin-fixed paraffin-embedded breast cancer samples. PD-L1 expression (Combined Positive Score, CPS ≥ 10%) was measured by immunohistochemistry (IHC; 22C3). Clinicopathologic variables were collected. Statistical associations between quantitative biomarkers, including 28 immune checkpoint genes, were calculated using Pearson correlations (r), and comparisons of quantitative biomarkers between groups were performed using the proportions test. For statistical significance, p&lt;0.05 was required. Results: The study cohort included 29 patients (24.2%) with TNBC and 91 (75.2%) with non-TNBC (including ER+/HER2- and HER2+). Most patients had metastatic tumors (n=92, 76.7%) and invasive ductal carcinoma (n=83, 69.2%). Among the TNBC group, 21 patients had PD-L1 positive tumors (72.4%), defined by CPS ≥ 10.In non-TNBC, VEGF has significant, though weak (r&lt;0.35) correlations with the expression of three checkpoint genes: AKT1 (r=0.35, p=0.00063), ICOS (r=0.34, p=0.00099), and TIM3 (r=0.29, p=0.0061). In TNBC, VEGF has significant, strong (r&gt;0.47) correlations with the expression of three other checkpoint genes: PD-1 (r=0.47, p=0.0094), PD-L1 (r=0.57, p=0.0012), and PIK3CA (r=0.6, p=0.00051) However, in TNBC, VEGF gene expression does not have a statistical association with PD-L1 IHC (CPS ≥/&lt; 10 (p=0.9)). Conclusions: Our findings suggest that there is an interplay between angiogenesis and an immunosuppressive tumor immune microenvironment in TNBC to a greater degree than in non-TNBCs. This supports the notion that angiogenesis mediators such as VEGF-A may enhance the expression of immunosuppressive checkpoint molecules, leading to immune evasion and tumor progression. Combination treatments of ICIs, especially anti-PD-1 therapy, with VEGF antibodies may be promising approaches to enhance the immune responses in TNBC, especially in tumors with CPS&lt;10, where the current frontline treatment is cytotoxic chemotherapy.

TRICK-MCC: A proof-of-concept, investigator-initiated study of combination therapy with anti–PD-1, anti–LAG-3, and anti–TIM-3 in participants with advanced or metastatic PD-(L)1 refractory Merkel cell carcinoma.

TPS9618 Background: Merkel cell carcinoma (MCC) is an aggressive and highly immunogenic skin cancer often associated with the Merkel cell polyomavirus (MCPyV). Immune checkpoint inhibition (ICI) via PD-(L)1 blockade can promote durable responses among patients with metastatic MCC, yet &gt;50% of MCC patients experience disease progression. There is an unmet need for effective treatment options for these patients. One possible strategy to overcome primary and secondary resistance in PD-(L)1 refractory MCC is concurrent targeting of multiple immune checkpoints to facilitate reversal of chronic T cell exhaustion. Based on our preliminary data revealing high expression of PD-1, LAG-3 and TIM-3 on MCC-specific CD8 T cells, which appear to increase upon clinical disease progression in the context of treatment with PD-(L)1 blockade, we hypothesize that concurrent blockade of PD-1, LAG-3 and TIM-3 will overcome immune evasion in patients with PD-(L) refractory MCC. Methods: TRICK-MCC (Triple Immune Checkpoint Inhibition in MCC) is an investigator initiated, Phase 2 clinical trial investigating concurrent treatment with anti-PD-1 (retifanlimab), anti-LAG3 (INCAGN02385) and anti-TIM-3 (INCAGN02390) in patients with advanced/metastatic MCC that has progressed after treatment with anti-PD-(L)1. Target enrollment is 20 patients total, with 5 patients enrolled as of Jan 2024. Patients will receive anti-PD-1 q4w and anti-TIM-3 and LAG-3 q2w for up to 24 weeks (Induction Phase) followed by all drugs q6w (Maintenance Phase). Treatment will end 2 years after starting the study drugs, or upon disease progression, unacceptable toxicity, or study withdrawal. Primary objective is objective response rate (ORR). Secondary objectives are duration of response, progression free survival, overall survival, and incidence and severity of adverse events. Interim analysis will be done after 10 patients have been enrolled and followed sufficiently long to assess ORR. An observed ORR of 25%will be considered as clinically meaningful in this population with no reliable standard treatments. Serial tumor biopsies and blood samples will be obtained in all patients, unless deemed unsafe or not feasible. Planned correlative studies aim to better characterize the prevalence and significance of cancer-specific T cell exhaustion (through rigorous study of MCPyV-specific T cells), the immunologic effects of triple ICI, and alternative mechanisms of PD-(L)1 resistance beyond T cell exhaustion in PD-(L)1 resistant tumors. We hope to gain insights that are broadly applicable to solid tumor immunotherapy. Clinical trial information: NCT06056895 .

Clinical landscape of precision oncology for rare cancers among diverse Asian populations: Insights from the MASTER KEY registry.

3024 Background: Despite considerable strides in novel cancer treatments, disparities in access and care persist globally. This is particularly pronounced for rare cancers and among Asian patient cohorts, presenting a dual challenge. Methods: We conducted an analysis on clinical and biomarker data from the MASTER KEY Study, a multi-regional, prospective, observational precision oncology initiative encompassing 3,764 rare cancer patients across Asia. Clinical treatment and biomarker data, inclusive of DNA/RNA sequencing, were scrutinized to compare precision oncology adoption across various countries. Results: Within the Japanese cohort (3,268 patients), predominant rare cancer types included soft tissue sarcomas (22.0%), CNS/brain tumors (12.8%), and head and neck tumors (9.2%). The broader Asian cohort (496 patients) included soft tissue sarcomas (14.6%), liver/biliary tract tumors (14.4%), and head and neck tumors (13.8%), drawing patients from Malaysia, Korea, Taiwan, Philippines, Thailand, and Vietnam. Clinical trial participation for these rare cancers was notably higher in Taiwan (8.2%), followed by Japan (6.5%) and Malaysia (2.0%). The utilization of molecular target agents and/or immune checkpoint inhibitors was highest in Japan (20.3%), trailed by Taiwan (18.9%) and Korea (12.8%). DNA/RNA targeted sequencing data was available for 1,852 patients in Japan (56.7%) and 321 patients (64.7%) across the rest of Asia. 19.5% and 7.0% received on-target therapy in Japan and the rest of Asia, respectively. Notably, in Japan, patients harboring detectable targetable genes like BRAF V600E, BRCA1, and BRCA2 received BRAF/MEK inhibitors and PARP inhibitors at rates of 78.3%, 37.8%, and 25.0%, respectively, with varying response rates of 33.3%, 18.2%, and 20.2% each. Intriguingly, TP53 mutation acted as a negative predictor for response to BRAF/MEK inhibitors. Notably, no patients in the Asian cohort received BRAF/MEK inhibitors or PARP inhibitors despite the detection of these genes. Conclusions: The MASTER KEY Study demonstrates the feasibility of a prospective precision oncology platform, spotlighting rare cancers and enabling on-label targeted therapy as well as off-label targeted therapy for a subset of patients through trials. However, the broader Asian population outside Japan encounters heightened limitations in accessing precision oncology. Urgent expansion of clinical trials throughout Asia is crucial to effectively address the disparity that lies within Asian rare cancer patients.