Combination Of Checkpoint Blockade Research Articles

TRP-2 / gp100 DNA vaccine and PD-1 checkpoint blockade combination for the treatment of intracranial tumors

Intracranial tumors present a significant therapeutic challenge due to their physiological location. Immunotherapy presents an attractive method for targeting these intracranial tumors due to relatively low toxicity and tumor specificity. Here we show that SCIB1, a TRP-2 and gp100 directed ImmunoBody® DNA vaccine, generates a strong TRP-2 specific immune response, as demonstrated by the high number of TRP2-specific IFNγ spots produced and the detection of a significant number of pentamer positive T cells in the spleen of vaccinated mice. Furthermore, vaccine-induced T cells were able to recognize and kill B16HHDII/DR1 cells after a short in vitro culture. Having found that glioblastoma multiforme (GBM) expresses significant levels of PD-L1 and IDO1, with PD-L1 correlating with poorer survival in patients with the mesenchymal subtype of GBM, we decided to combine SCIB1 ImmunoBody® with PD-1 immune checkpoint blockade to treat mice harboring intracranial tumors expressing TRP-2 and gp100. Time-to-death was significantly prolonged, and this correlated with increased CD4+ and CD8+ T cell infiltration in the tissue microenvironment (TME). However, in addition to PD-L1 and IDO, the GBM TME was found to contain a significant number of immunoregulatory T (Treg) cell-associated transcripts, and the presence of such cells is likely to significantly affect clinical outcome unless also tackled.

Characterizing the tumor and immune landscape of patients with melanoma treated with combined checkpoint blockade and MAPK-targeted therapy.

e21503 Background: Melanoma therapy has been revolutionized by two novel therapeutic approaches: mitogen activated protein kinase (MAPK) targeted therapy (MTT) and immune checkpoint blockade therapy (ICB). It has been shown that MTT enhances anti-tumor immunity within the tumor microenviroment (TME), thus providing a strong rationale for its combination with immunotherapy. Regimens combining MTT with ICB there have had mixed results, and which patients (pts) should be treated with these combinations is unknown. Methods: 16 pts harboring BRAFV600 mutation were enrolled and treated with 2 weeks (wks) of MTT (dabrafenib plus trametinib) then 6 wks of concomitant MTT and pembrolizumab, followed by single-agent pembrolizumab. The primary endpoint was clinical benefit (CB) defined as partial/complete response or stable disease (per RECIST1.1) persisting at 24 wks. Serial biopsies were performed prior to MTT, following the 2-week lead-in of MTT, and following 6 wks of combination immune therapy. Single-cell RNA-seq profiling of CD45+ and CD45- cells was performed using both the smart-seq2 plate-based protocol and 10x genomics platform. Results: Out of the 16 pts, 14 received both MTT and ICB, of them only 5 pts had CB. 2 pts did not receive ICB due to MTT toxicity. A clustering analysis of all immune cells showed a significant recruitment of Cytotoxic CD8+ T cells after MTT treatment in pts with CB. In addition T cell clusters had a significantly higher expression of IFNG pathway genes at both baseline and after MTT compared to NCB pts. Tumor associated macrophages (TAM) in NCB pts possessed mainly a “M2” phenotype and expressed a significantly higher level of immune suppressor genes, such as HLA-G, PLAC8 and CD52. In contrast, most of the TAMs occupying the tumor of CB pts had M1 phenotype, and significantly expressed APOE, IL10, CXC12. Calculation of M1/M2 score correlated with chemokines expressed by tumor cells such as CCL3 and TIGIT. In addition, MAPK-pathway genes expressed by the tumor cells were down-regulated after MTT in both CB & NCB pts, and up-regulated after ICB, but only in NCB pts. Our analysis also revealed tumor programs that were significantly higher in NCB patients: the first expressing high MITF-SOX levels pre-therapy that decreased after MTT, the second expressing AXL, low at baseline and up regulated after combination treatment. These AXL expressing cells also had a significantly higher TGF-β expression levels. Moreover, MITF/AXL ratio in NCB patients decreased significantly after MTT and after ICB. Conclusions: Overall, abbreviated MTT with ICB did not lead to increased CB. Our findings highlights factors that modify the TME towards immune suppression, tumor programs resistance, MAPK up-regulation and can thus enhance drug resistance. Clinical trial information: NCT03149029 .

Considerations for anti-PD1-based first-line treatment of Hodgkin lymphoma.

Anti-PD1-based first-line treatment holds great promise in classical Hodgkin lymphoma. The management of immune-related adverse events in the context of time-limited combined checkpoint blockade and chemotherapy administered in curative intent is a challenge. Kuczmarski and Lynch provide a case-based approach to key toxicities observed in this setting. Commentary on: Kuczmarski etal. Managing common toxicities associated with checkpoint inhibitor and chemotherapy combinations for untreated classic Hodgkin lymphoma. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19478.

Tregs protect against combination checkpoint blockade toxicity induced by TPH and B cell interactions.

Tregs protect against combination checkpoint blockade toxicity induced by TPH and B cell interactions.

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.

Vaccination with DC-SIGN-Targeting αGC Liposomes Leads to Tumor Control, Irrespective of Suboptimally Activated T-Cells.

Cancer vaccines have emerged as a potent strategy to improve cancer immunity, with or without the combination of checkpoint blockade. In our investigation, liposomal formulations containing synthetic long peptides and α-Galactosylceramide, along with a DC-SIGN-targeting ligand, Lewis Y (LeY), were studied for their anti-tumor potential. The formulated liposomes boosted with anti-CD40 adjuvant demonstrated robust invariant natural killer (iNKT), CD4+, and CD8+ T-cell activation in vivo. The incorporation of LeY facilitated the targeting of antigen-presenting cells expressing DC-SIGN in vitro and in vivo. Surprisingly, mice vaccinated with LeY-modified liposomes exhibited comparable tumor reduction and survival rates to those treated with untargeted counterparts despite a decrease in antigen-specific CD8+ T-cell responses. These results suggest that impaired induction of antigen-specific CD8+ T-cells via DC-SIGN targeting does not compromise anti-tumor potential, hinting at alternative immune activation routes beyond CD8+ T-cell activation.

Efficacy and safety of bispecific antibodies vs. immune checkpoint blockade combination therapy in cancer: a real-world comparison.

Emerging tumor immunotherapy methods encompass bispecific antibodies (BSABs), immune checkpoint inhibitors (ICIs), and adoptive cell immunotherapy. BSABs belong to the antibody family that can specifically recognize two different antigens or epitopes on the same antigen. These antibodies demonstrate superior clinical efficacy than monoclonal antibodies, indicating their role as a promising tumor immunotherapy option. Immune checkpoints are also important in tumor immunotherapy. Programmed cell death protein-1 (PD-1) is a widely acknowledged immune checkpoint target with effective anti-tumor activity. PD-1 inhibitors have demonstrated notable therapeutic efficacy in treating hematological and solid tumors; however, more than 50% of patients undergoing this treatment exhibit a poor response. However, ICI-based combination therapies (ICI combination therapies) have been demonstrated to synergistically increase anti-tumor effects and immune response rates. In this review, we compare the clinical efficacy and side effects of BSABs and ICI combination therapies in real-world tumor immunotherapy, aiming to provide evidence-based approaches for clinical research and personalized tumor diagnosis and treatment.

Abstract B084: Triple checkpoint blockade, but not anti-PD1 alone, enhances the efficacy of engineered adoptive T cell therapy in advanced ovarian cancer

Abstract Background: Over 20,000 women are diagnosed with ovarian cancer annually, and more than half will die within 5 years. This rate has changed little in the last 30 years, highlighting the need for therapy innovation. Although immunotherapy has revolutionized cancer treatment, efforts to harness endogenous patient immune responses have yielded limited therapeutic activity in ovarian cancer patients. T cells engineered to express a T cell receptor (TCR) targeting proteins uniquely overexpressed in tumors have the potential to control tumor growth without toxicity. Mesothelin (Msln) is over-expressed in ovarian cancer, contributes to the malignant and invasive phenotype, and has limited expression in healthy cells, making it a candidate immunotherapy target in these tumors. Methods: The ID8VEGF mouse cell line was used to evaluate if T cells engineered to express a mouse Msln-specific high-affinity T cell receptor (TCRMsln) can kill ovarian cancer. Tumor-bearing mice were treated with TCRMsln T cells plus anti-PD-1, anti-Tim-3 or anti-Lag-3 checkpoint-blocking antibodies alone or in combination, ultimately targeting up to three inhibitory receptors simultaneously. Single-cell RNA-sequencing (scRNAseq) was used to profile the impact of combination checkpoint blockade on engineered T cells and the tumor microenvironment (TME). Results: In a disseminated ID8 tumor model, adoptively transferred TCRMsln T cells preferentially accumulated in established tumors, delayed ovarian tumor growth, and prolonged mouse survival. However, elements in the TME limited engineered T cell persistence and cytolytic function. Triple checkpoint blockade, but not single- or double-agent treatment, dramatically increased antitumor function by intratumoral TCRMsln T cells. scRNAseq of tumor-infiltrating cells revealed distinct transcriptome changes in engineered and endogenous T cells and myeloid-derived cells. Engineered T cells, when combined with triple checkpoint blockade, increased expression of genes associated with effector and memory gene signatures, including proliferation and metabolic function, and reduced expression of genes associated with exhaustion. Moreover, combining adoptive immunotherapy with triple checkpoint blockade significantly prolonged survival in the cohort of treated tumor-bearing mice, relative to mice that received TCRMsln T cells alone or with anti-PD1 or double-agent treatments. Conclusions: Inhibitory receptor/ligand interactions within the TME can dramatically reduce T cell function, suggesting tumor cells may upregulate the ligands for PD-1, Tim-3 and Lag-3 for protection from tumor-infiltrating lymphocytes. In an advanced ovarian cancer model, triple checkpoint blockade significantly improved engineered T cell function and outcomes in mice in a setting where single checkpoint blockade had no significant activity. These results suggest that disrupting multiple inhibitory pathways simultaneously, which can be more safely pursed in a cell intrinsic form through genetic engineering, may be necessary for improved efficacy in patients. Citation Format: Kristin G. Anderson, Yapeng Su, Madison G. Burnett, Breanna M. Bates, Magdalia L. Rodgers Suarez, Susan L. Ruskin, Valentin Voillet, Raphael Gottardo, Philip D. Greenberg. Triple checkpoint blockade, but not anti-PD1 alone, enhances the efficacy of engineered adoptive T cell therapy in advanced ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr B084.

Identification of immune cell-related prognostic genes characterized by a distinct microenvironment in hepatocellular carcinoma.

The development and progression of hepatocellular carcinoma (HCC) have been reported to be associated with immune-related genes and the tumor microenvironment. Nevertheless, there are not enough prognostic biomarkers and models available for clinical use. Based on seven prognostic genes, this study calculated overall survival in patients with HCC using a prognostic survival model and revealed the immune status of the tumor microenvironment (TME). To develop a novel immune cell-related prognostic model of HCC and depict the basic profile of the immune response in HCC. We obtained clinical information and gene expression data of HCC from The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) datasets. TCGA and ICGC datasets were used for screening prognostic genes along with developing and validating a seven-gene prognostic survival model by weighted gene coexpression network analysis and least absolute shrinkage and selection operator regression with Cox regression. The relative analysis of tumor mutation burden (TMB), TME cell infiltration, immune checkpoints, immune therapy, and functional pathways was also performed based on prognostic genes. Seven prognostic genes were identified for signature construction. Survival receiver operating characteristic curve analysis showed the good performance of survival prediction. TMB could be regarded as an independent factor in HCC survival prediction. There was a significant difference in stromal score, immune score, and estimate score between the high-risk and low-risk groups stratified based on the risk score derived from the seven-gene prognostic model. Several immune checkpoints, including VTCN1 and TNFSF9, were found to be associated with the seven prognostic genes and risk score. Different combinations of checkpoint blockade targeting inhibitory CTLA4 and PD1 receptors and potential chemotherapy drugs hold great promise for specific HCC therapies. Potential pathways, such as cell cycle regulation and metabolism of some amino acids, were also identified and analyzed. The novel seven-gene (CYTH3, ENG, HTRA3, PDZD4, SAMD14, PGF, and PLN) prognostic model showed high predictive efficiency. The TMB analysis based on the seven genes could depict the basic profile of the immune response in HCC, which might be worthy of clinical application.

Treatment-related adverse events, including fatal toxicities, in patients with solid tumours receiving neoadjuvant and adjuvant immune checkpoint blockade: a systematic review and meta-analysis of randomised controlled trials

Incorporating immune checkpoint blockade into perioperative cancer therapy has improved clinical outcomes. However, the safety of immune checkpoint blockade needs better evaluation, given the chances of more prolonged disease-free survival. We aimed to assess how adding immune checkpoint blockade to perioperative therapy affects treatment-related adverse events. For this systematic review and meta-analysis, we searched PubMed/MEDLINE, Embase, Web of Science, and the Cochrane Library from database inception until Aug 8, 2023, for randomised controlled trials that assessed the addition of immune checkpoint blockade to neoadjuvant or adjuvant therapy for cancer, reported treatment-related deaths, and had a design in which the experimental group assessed immune checkpoint blockade in combination with the therapy used in the control group. Meta-analysis was done to pool odds ratios (ORs) of treatment-related deaths, any grade and grade 3-4 treatment-related adverse events, serious adverse events, and adverse events leading to treatment discontinuation. The protocol is registered with PROSPERO, CRD42022343741. 28 randomised controlled trials with 16 976 patients were included. The addition of immune checkpoint blockade was not significantly associated with increased treatment-related deaths (OR 1·76, 95% CI 0·95-3·25; p=0·073), consistent across immune checkpoint blockade subtype (I2=0%). 40 fatal toxicities were identified across 9864 patients treated with immune checkpoint blockade, with pneumonitis being the most common (six [15·0%]); 13 fatal toxicities occurred among 7112 patients who were not treated with immune checkpoint blockade. The addition of immune checkpoint blockade increased the incidence of grade 3-4 treatment-related adverse events (OR 2·73, 95% CI 1·98-3·76; p<0·0001), adverse events leading to treatment discontinuation (3·67, 2·45-5·51; p<0·0001), and treatment-related adverse events of any grade (2·60 [1·88-3·61], p<0·0001). The immune checkpoint blockade versus placebo design primarily used as adjuvant therapy was associated with increased incidence of treatment-related deaths (4·02, 1·04-15·63; p=0·044) and grade 3-4 adverse events (5·31, 3·08-9·15; p<0·0001), whereas the addition of immune checkpoint blockade in the neoadjuvant setting was not associated with increased incidence of treatment-related death (1·11, 95% CI 0·38-3·29; p=0·84) or grade 3-4 adverse events (1·17, 0·90-1·51; p=0·23). The addition of immune checkpoint blockade to perioperative therapy was associated with an increase in grade 3-4 treatment-related adverse events and adverse events leading to treatment discontinuation. These findings provide safety insights for further clinical trials assessing neoadjuvant or adjuvant immune checkpoint blockade therapy. Clinicians should closely monitor patients for treatment-related adverse events to prevent treatment discontinuations and morbidity from these therapies in earlier-stage settings. None.

ICBcomb: a comprehensive expression database for immune checkpoint blockade combination therapy.

The success of immune checkpoint blockade (ICB) promotes the immunotherapy to be a new pillar in cancer treatment. However, the low response rate of the ICB therapy limits its application. To increase the response rate and enhance efficacy, the ICB combination therapy has emerged and its clinical trials are increasing. Nevertheless, the gene expression profile and its pattern of ICB combination were not comprehensively studied, which limits the understanding of the ICB combination therapy and the identification of new drugs. Here, we constructed ICBcomb (http://bioinfo.life.hust.edu.cn/ICBcomb/), a comprehensive database, by analyzing the human and mouse expression data of the ICB combination therapy and comparing them between groups treated with ICB, other drugs or their combinations. ICBcomb contains 1399 samples across 29 cancer types involving 52 drugs. It provides a user-friendly web interface for demonstrating the results of the available comparisons in the ICB combination therapy datasets with five functional modules: [1, 2] the 'Dataset/Disease' modules for browsing the expression, enrichment and comparison results in each dataset or disease; [3] the 'Gene' module for inputting a gene symbol and displaying its expression and comparison results across datasets/diseases; [4] the 'Gene Set' module for GSVA/GSEA enrichment analysis on the built-in gene sets and the user-input gene sets in different comparisons; [5] the 'Immune Cell' module for immune cell infiltration comparison between different groups by immune cell abundance analysis. The ICBcomb database provides the first resource for gene expression profile and comparison in ICB combination therapy, which may provide clues for discovering the mechanism of effective combination strategies and new combinatory drugs.

P2.21-02 A Combination of PD-1 and TIGIT Checkpoint Blockade Elicits a Strong Antitumor Response in the Patient and Mouse Pleural Mesothelioma Model

P2.21-02 A Combination of PD-1 and TIGIT Checkpoint Blockade Elicits a Strong Antitumor Response in the Patient and Mouse Pleural Mesothelioma Model

Combination Therapies to Improve the Efficacy of Immunotherapy in Triple-negative Breast Cancer.

Immune checkpoint inhibition combined with chemotherapy is currently approved as first-line treatment for patients with advanced PD-L1-positive triple-negative breast cancer (TNBC). However, a significant proportion of metastatic TNBC is PD-L1-negative and, in this population, chemotherapy alone largely remains the standard-of-care and novel therapeutic strategies are needed to improve clinical outcomes. Here, we describe a triple combination of anti-PD-L1 immune checkpoint blockade, epigenetic modulation thorough bromodomain and extra-terminal (BET) bromodomain inhibition (BBDI), and chemotherapy with paclitaxel that effectively inhibits both primary and metastatic tumor growth in two different syngeneic murine models of TNBC. Detailed cellular and molecular profiling of tumors from single and combination treatment arms revealed increased T- and B-cell infiltration and macrophage reprogramming from MHCIIlow to a MHCIIhigh phenotype in mice treated with triple combination. Triple combination also had a major impact on gene expression and chromatin profiles shifting cells to a more immunogenic and senescent state. Our results provide strong preclinical evidence to justify clinical testing of BBDI, paclitaxel, and immune checkpoint blockade combination.

Medical Gas Plasma Technology Combines with Antimelanoma Therapies and Promotes Immune-Checkpoint Therapy Responses.

Strategies to improve activity and selectivity are major goals in oncological drug development. Medical gas plasma therapy has been subject to intense research in dermatooncology recently. Based on partial gas ionization, this approach is exceptional in generating a variety of reactive oxygen species simultaneously that can be applied locally at the tumor side. It is hypothesized that combined gas plasma treatment can potentiate drug responses in the treatment of melanoma. Using a plasma jet approved as medical device in Europe, a systematic screening of 46 mitochondria-targeted drugs identifies five agents synergizing in vitro and in vivo. Increased intratumoral leucocyte infiltration points to immunomodulatory aspects of the treatment, motivating to investigate responses to immune checkpoint blockade in combination with plasma. Tumor growth is monitored based on bioluminescent imaging, and single-cell suspensions are retrieved from each tumor to characterize tumor-infiltrating leucocytes using multicolor flow cytometry. Gene expression profiling is done using a validated NanoString panel targeting 770 genes specifically designed for immuno-oncological research. Cell type abundancies are characterized from bulk RNA samples using the CIBERSORT computational framework. Collectively, the results indicate that local application of medical gas plasma technology synergizes with mitochondria-targeted drugs and anti-PD1 checkpoint therapy in treating melanoma.

Combination of PD-1 Checkpoint Blockade and Botulinum Toxin Type A1 Improves Antitumor Responses in Mouse Tumor Models of Melanoma and Colon Carcinoma

ABSTRACT Background Tumor innervation has been shown to be utilized by some solid cancers to support tumor initiation, growth, progression, and metastasis, as well as confer resistance to immune checkpoint blockade through suppression of antitumor immunologic responses. Since botulinum neurotoxin type A1 (BoNT/A1) blocks neuronal cholinergic signaling, its potential use as an anticancer drug in combination with anti-PD-1 therapy was investigated in four different syngeneic mouse tumor models. Methods Mice implanted with breast (4T1), lung (LLC1), colon (MC38), and melanoma (B16-F10) tumors were administered a single intratumoral injection of 15 U/kg BoNT/A1, repeated intraperitoneal injections of 5 mg/kg anti-PD-1 (RMP1-14), or both. Results Compared to the single-agent treatments, anti-PD-1 and BoNT/A1 combination treatment elicited significant reduction in tumor growth among B16-F10 and MC38 tumor-bearing mice. The combination treatment also lowered serum exosome levels in these mice compared to the placebo control group. In the B16-F10 syngeneic mouse tumor model, anti-PD-1 + BoNT/A1 combination treatment lowered the proportion of MDSCs, negated the increased proportion of Treg cells, and elicited a higher number of tumor-infiltrating CD4+ and CD8+ T lymphocytes into the tumor microenvironment compared to anti-PD-1 treatment alone. Conclusion Our findings demonstrate the synergistic antitumor effects of BoNT/A1 and PD-1 checkpoint blockade in mouse tumor models of melanoma and colon carcinoma. These findings provide some evidence on the potential application of BoNT/A1 as an anticancer drug in combination with immune checkpoint blockade and should be further explored.

Multivalent Carbohydrate Nanocomposites for Tumor Microenvironment Remodeling to Enhance Antitumor Immunity.

Current cancer immunotherapeutic strategies mainly focus on remodeling the tumor microenvironment (TME) to make it favorable for antitumor immunity. Increasing attention has been paid to developing innovative immunomodulatory adjuvants that can restore weakened antitumor immunity by conferring immunogenicity to inflamed tumor tissues. Here, a galactan-enriched nanocomposite (Gal-NC) is developed from native carbohydrate structures through an optimized enzymatic transformation for effective, stable, and biosafe innate immunomodulation. Gal-NC is characterized as a carbohydrate nanoadjuvant with a macrophage-targeting feature. It is composed of repeating galactan glycopatterns derived from heteropolysaccharide structures of plant origin. The galactan repeats of Gal-NC function as multivalent pattern-recognition sites for Toll-like receptor 4 (TLR4). Functionally, Gal-NC-mediated TLR activation induces the repolarization of tumor-associated macrophages (TAMs) toward immunostimulatory/tumoricidal M1-like phenotypes. Gal-NC increases the intratumoral population of cytotoxic T cells, the main effector cells of antitumor immunity, via re-educated TAMs. These TME alterations synergistically enhance the T-cell-mediated antitumor response induced by αPD-1 administration, suggesting that Gal-NC has potential value as an adjuvant for immune checkpoint blockade combination therapies. Thus, the Gal-NC model established herein suggests a glycoengineering strategy to design a carbohydrate-based nanocomposite for advanced cancer immunotherapies.

Abstract 6392: Combination of pulsed electric field, immunotherapy and cisplatin significantly prolongs survival in an orthotopic breast cancer mouse model

Abstract Introduction: Pulsed Electric Field (PEF) therapy is a novel approach to treat cancer by providing focal tumor ablation while sparing sensitive structures within the tumor micro-environment. Previous studies have demonstrated that PEF induces immunogenic cell death by activating inflammatory signaling pathways and stimulation of antigen presenting cells withing the tumor micro-environment. PEF ablation provides a tumor focused in situ vaccination strategy that combines with checkpoint blockade. We hypothesized that PEF ablation should synergize with chemotherapy and anti-PD1 in a model where checkpoint inhibitors are inactive. Experimental Design: To test this hypothesis, we utilized a highly aggressive syngeneic orthotopic triple negative breast cancer 4T1 mouse model that is non-responsive to anti-PD1 and only marginally responsive to cisplatin to determine if this combination treatment could prolong survival. Thirty-two Balb/c mice were inoculated in the mammary fat pad with 200,000 4T1 cells. Once tumors were established (5mm in diameter), animals were randomized to the following groups: (A) Sham/IgG control (n=8; needle inserted but no PEF), (B) PEF only (n=8), (C) cisplatin + anti-PD-1 (n=8) and (D) PEF + cisplatin + anti PD-1 (n=8). Tumors in groups B and D were treated once with PEF. Anti-PD1 and isotype matched control IgG was administered once per week (200μg, i.p injections) starting on the day of PEF (Group D) for four weeks. Cisplatin was administered (2mg/kg, i.v) once per week for four weeks starting on the day of PEF (d=0) for four weeks. All the mammary fat pad tumors were resected when they achieved a tumor volume of ~200 mm3 to recapitulate post-resection metastatic relapse (See Schematic 1). Results and Conclusions: All mice in the Sham-control IgG group needed to be euthanized by day 43 due to metastases in multiple organs including lungs, bones, liver and brain. All mice in the cisplatin + anti PD-1 group had to be euthanized by day 74. Interestingly, all groups that were treated with PEF survived much longer. On day 90, 28% of mice in the PEF alone group were alive and 43% were alive in the PEF + anti-PD1 + Cisplatin (see Figure 1). The rank-log p-value for the Kaplan-Meier survival curve was statistically significant. In conclusion, our results demonstrate that PEF treatment in combination with anti-PD1 and Cisplatin significantly prolongs survival in a highly aggressive triple negative breast tumor mouse model that is non-responsive to immunotherapy. These findings support evaluation of PEF in cancer patients that are receiving combination of checkpoint blockade and chemotherapy. Citation Format: Chiara Pastori, Mukta Wagh, Ebtesam Nafie, Fatima Murad, Mohit Trikha, Robert Neal. Combination of pulsed electric field, immunotherapy and cisplatin significantly prolongs survival in an orthotopic breast cancer mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6392.

A novel immune-related model to predict prognosis and responsiveness to checkpoint and angiogenesis blockade therapy in advanced renal cancer.

Immune checkpoint blockade (ICB) and anti-angiogenic drug combination has prolonged the survival of patients with advanced renal cell carcinoma (RCC). However, not all patients receive clinical benefits from this intervention. In this study, we aimed to establish a promising immune-related prognostic model to stratify the patients responding to ICB and anti-angiogenic drug combination and facilitate the development of personalized therapies for patients with RCC. Based on clinical annotations and RNA-sequencing (RNA-seq) data of 407 patients with advanced RCC from the IMmotion151 cohort, nine immune-associated differentially expressed genes (DEGs) between responders and non-responders to atezolizumab (anti-programmed death-ligand 1 antibody) plus bevacizumab (anti-vascular endothelial growth factor antibody) treatment were identified via weighted gene co-expression network analysis. We also conducted single-sample gene set enrichment analysis to develop a novel immune-related risk score (IRS) model and further estimate the prognosis of patients with RCC by predicting their sensitivity to chemotherapy and responsiveness to immunotherapy. IRS model was further validated using the JAVELIN Renal 101 cohort, the E-MTAB-3218 cohort, the IMvigor210 and GSE78220 cohort. Predictive significance of the IRS model for advanced RCC was assessed using receiver operating characteristic curves. The IRS model was constructed using nine immune-associated DEGs: SPINK5, SEMA3E, ROBO2, BMP5, ORM1, CRP, CTSE, PMCH and CCL3L1. Advanced RCC patients with high IRS had a high risk of undesirable clinical outcomes (hazard ratio = 1.91; 95% confidence interval = 1.43-2.55; P < 0.0001). Transcriptome analysis revealed that the IRS-low group exhibited significantly high expression levels of CD8+ T effectors, antigen-processing machinery, and immune checkpoints, whereas the epithelial-mesenchymal transition pathway was enriched in the IRS-high group. IRS model effectively differentiated the responders from non-responders to ICB combined with angiogenesis blockade therapy or immunotherapy alone, with area under the curve values of 0.822 in the IMmotion151 cohort, 0.751 in the JAVELIN Renal 101 cohort, and 0.776 in the E-MTAB-3218 cohort. IRS model is a reliable and robust immune signature that can be used for patient selection to optimize the efficacy of ICB plus anti-angiogenic drug therapies in patients with advanced RCC.

Driver Mutations Dictate the Immunologic Landscape and Response to Checkpoint Immunotherapy of Glioblastoma.

The composition of the tumor immune microenvironment (TIME) is considered a key determinant of patients' response to immunotherapy. The mechanisms underlying TIME formation and development over time are poorly understood. Glioblastoma (GBM) is a lethal primary brain cancer for which there are no curative treatments. GBMs are immunologically heterogeneous and impervious to checkpoint blockade immunotherapies. Utilizing clinically relevant genetic mouse models of GBM, we identified distinct immune landscapes associated with expression of EGFR wild-type and mutant EGFRvIII cancer driver mutations. Over time, accumulation of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) was more pronounced in EGFRvIII-driven GBMs and was correlated with resistance to PD-1 and CTLA-4 combination checkpoint blockade immunotherapy. We determined that GBM-secreted CXCL1/2/3 and PMN-MDSC-expressed CXCR2 formed an axis regulating output of PMN-MDSCs from the bone marrow leading to systemic increase in these cells in the spleen and GBM tumor-draining lymph nodes. Pharmacologic targeting of this axis induced a systemic decrease in the numbers of PMN-MDSC, facilitated responses to PD-1 and CTLA-4 combination checkpoint blocking immunotherapy, and prolonged survival in mice bearing EGFRvIII-driven GBM. Our results uncover a relationship between cancer driver mutations, TIME composition, and sensitivity to checkpoint blockade in GBM and support the stratification of patients with GBM for checkpoint blockade therapy based on integrated genotypic and immunologic profiles.

Catalytically Active Metal-Organic Frameworks Elicit Robust Immune Response to Combination Chemodynamic and Checkpoint Blockade Immunotherapy.

Chemodynamic therapy (CDT) strategies rely on the generation of reactive oxygen species (ROS) to kill tumor cells, with hydroxyl radicals (•OH) serving as the key mediators of cytotoxicity in this setting. However, the efficacy of CDT approaches is often hampered by the properties of the tumor microenvironment (TME) and associated limitations to the Fenton reaction that constrains ROS generation. As such, there is a pressing need for the design of new nanoplatforms capable of improving CDT outcomes. In this study, an Fc-based metal-organic framework (MOF) vitamin k3 (Vk3)-loaded cascade catalytic nanoplatform (Vk3@Co-Fc) was developed. This platform was capable of undergoing TME-responsive degradation without impacting normal cells. After its release, Vk3 was processed by nicotinamide adenine dinucleotide hydrogen phosphate (NAD(P)H) quinone oxidoreductase-1 (NQO1), which is highly expressed in tumor cells, thereby yielding large quantities of H2O2 that in turn interact with Fe ions via the Fenton reaction to facilitate in situ cytotoxic •OH production. This process leads to immunogenic cell death (ICD) of the tumor, which then promotes dendritic cell maturation and ultimately increases T cell infiltration into the tumor site. When this nanoplatform was combined with programmed death 1 (PD-1) checkpoint blockade approaches, it was sufficient to enhance tumor-associated immune responses in breast cancer as evidenced by increases in the frequencies of CD45+ leukocytes and CD8+ cytotoxic T lymphocytes, thereby inhibiting tumor metastasis to the lungs and improving murine survival outcomes. Together, this Vk3@Co-Fc cascading catalytic nanoplatform enables potent cancer immunotherapy for breast cancer regression and metastasis prevention.