Triple Blockade Research Articles

Triple Blockade of Oncogenic RAS Signaling Using KRAS and MEK Inhibitors in Combination with Irradiation in Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest of human malignancies and carries an exceptionally poor prognosis. It is mostly driven by multiple oncogenic alterations, with the highest mutation frequency being observed in the KRAS gene, which is a key oncogenic driver of tumorogenesis and malignant progression in PDAC. However, KRAS remained undruggable for decades until the emergence of G12C mutation specific KRAS inhibitors. Despite this development, this therapeutic approach to target KRAS directly is not routinely used for PDAC patients, with the reasons being the rare presence of G12C mutation in PDAC with only 1-2% of occurring cases, modest therapeutic efficacy, activation of compensatory pathways leading to cell resistance, and absence of effective KRASG12D or pan-KRAS inhibitors. Additionally, indirect approaches to targeting KRAS through upstream and downstream regulators or effectors were also found to be either ineffective or known to cause major toxicities. For this reason, new and more effective treatment strategies that combine different therapeutic modalities aiming at achieving synergism and minimizing intrinsic or adaptive resistance mechanisms are required. In the current work presented here, pancreatic cancer cell lines with oncogenic KRAS G12C, G12D, or wild-type KRAS were treated with specific KRAS or SOS1/2 inhibitors, and therapeutic synergisms with concomitant MEK inhibition and irradiation were systematically evaluated by means of cell viability, 2D-clonogenic, 3D-anchorage independent soft agar, and bioluminescent ATP assays. Underlying pathophysiological mechanisms were examined by using Western blot analyses, apoptosis assay, and RAS activation assay.

Abstract 4041: Translational assessment of triple combination with Tislelizumab (anti-PD-1), LBL-007 (anti-LAG-3) and < for Surzebiclimab (anti-TIM-3) highlights its strong anti-tumor activity and < for clinical potential in solid tumors such as HNSCC

Abstract Background: Therapeutics targeting PD-(L)1 have demonstrated impressive clinical activity in several type of cancers. However, only a small proportion of patients develop long-term response and resistance frequently occurs. LAG-3 and TIM-3 are inhibitory immune checkpoints frequently upregulated and co-expressed with PD-1 on tumor-infiltrating T cells, contributing to T cell dysfunction. Thus, we hypothesized that simultaneously targeting PD-1/LAG-3/TIM-3 would further restore T cell response and the triple combination of Tislelizumab (Tisle, anti-PD-1), LBL-007 (anti-LAG-3) and Surzebiclimab (Surze, anti-TIM-3) would provide greater clinical benefit.Methods: To evaluate the rationale and the anti-tumor activity of triple combination, LAG-3 and TIM-3 expression were analyzed in in vitro T cells, syngeneic mouse models and cancer patients with anti-PD-(L)1 therapy. The effects of dual blockade of PD-1/LAG-3, PD-1/TIM-3 and the triple blockade of PD-1/LAG-3/TIM-3 on T cell function were evaluated in in vitro activated PBMCs and the anti-tumor efficacy were evaluated in syngeneic mouse models. Relevant gene expression and immune signatures were ranked across 31 solid tumor types in TCGA.Results: Both LAG-3 and TIM-3 expression on T cells were upregulated by anti-PD-1 treatment in syngeneic mouse tumors, similar trend was observed in cancer patients with anti-PD-(L)1 therapy. Dual combination of Tisle/LBL-007 or Tisle/Surze enhanced IFNγ production in in vitro activated human T cells. The dual blockade of PD-1/LAG-3 or PD-1/TIM-3 significantly enhanced tumor growth inhibition compared with anti-PD-1 monotherapy in syngeneic mouse models. The triple combination of Tisle/LBL-007/Surze further enhanced IFNγ production in in vitro activated T cells. In a mouse MC38 colon carcinoma model, the triple blockade of PD-1/LAG-3/TIM-3 demonstrated enhanced anti-tumor activity compared with either dual combination, evidenced by trend of increased tumor growth inhibition and higher tumor-free incidence rate. Finally, the responsiveness of PD-1/LAG-3/TIM-3 triple combination was predicted using 5 signatures, including early effector T cell signature, inflamed signature, LAG-3, TIM-3 and PD-L1 expression. The in silico analyses indicated strong potential in clinical utility such as squamous cell carcinoma of the head and neck (HNSCC).Conclusions: The concurrent blockade of PD-1/LAG-3/TIM-3 represents a promising strategy to enhance T cell function and anti-tumor activity. The results demonstrated the therapeutic potential of the triple combination. A Ph2 study evaluating Tisle in combination with LBL-007 and/or Surze in first-line treatment of recurrent or metastatic HNSCC (NCT05909904) is recruiting. Citation Format: Hengrui Zhu, Jinhui Zhang, Han Yan, Xiao Ding, Juan Yang, Yu Jiang, Minjuan Deng, Haoxuan Song, Fangfang Ping, Fuyun Sun, Xiaoyu Li, Lijie Zhang, Bin Jiang, Weiwei Song, Zhirong Shen, Wei Jin, Jiyuan Zhang, Yun Zhang. Translational assessment of triple combination with Tislelizumab (anti-PD-1), LBL-007 (anti-LAG-3) and < for Surzebiclimab (anti-TIM-3) highlights its strong anti-tumor activity and < for clinical potential in solid tumors such as HNSCC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4041.

Preliminary antitumor activity of the combination of COM701 + BMS-986207 + nivolumab in patients with recurrent, metastatic MSS endometrial cancer.

5595 Background: There is a high unmet medical need for the treatment of patients [pts] with microsatellite stable [MSS], recurrent, metastatic, endometrial cancer [EC]. We reported encouraging preliminary antitumor activity with the triple combination of COM701 + BMS-986207 + nivolumab in patients with platinum resistant epithelial ovarian cancer [1]. COM701 is a novel, 1st-in-class immune checkpoint inhibitor [ICI] that binds to PVRIG, a DNAM-1 axis member, leading to activation of T-and NK-cells; BMS-986207 is an ICI of TIGIT. Nivolumab is an ICI of PD-1. We hypothesized that in pts with EC, the triple combination would demonstrate antitumor activity with a favorable safety and tolerability profile. We present encouraging preliminary results. Methods: As part of an expansion cohort, we enrolled 9 patients [pts] with EC. All pts received COM701 20 mg/kg + BMS-986207 480 mg + nivolumab 480 mg all IV Q4W. Primary objectives were safety/tolerability, with secondary objective of antitumor activity in pts with EC. Key inclusion criteria: Age ≥ 18 yrs, measurable disease, MSS by IHC or genomic testing, ≤2 prior systemic cytotoxic therapies, prior PD-1/PD-L1 permissible. Key exclusion criteria: prior receipt of anti-PVRIG, anti-TIGIT. Investigator assessed responses were per RECIST v1.1, safety per CTCAE v5.0. Results: Median age 71yrs, median of 2 prior lines of therapy, prior PD-1/PD-L1 3/9 [33%]. All pts received prior cytotoxic therapy. Objective response rate (ORR) 2/9 [22%] pts; 2 pts with SD. Disease control rate [CR + PR + SD] 4/9 [44%]. There were 2 pts with confirmed PR; 1 of these pts was refractory to prior receipt of lenvatinib + pembrolizumab [best response assessment of progressive disease]. Treatment related AEs were reported in 6/9 [67%] pts, the majority 4/6 [67%] were Grade 1 [1 pt each with chills, pyrexia, back pain and pruritus, lipase increased]. No new safety signals are reported. Conclusions: The combination of COM701 + BMS-986207 + nivolumab demonstrates encouraging preliminary signal of antitumor activity in pts with EC including in a pt refractory to prior exposure to lenvatinib + pembrolizumab. The triplet combination has a favorable safety/tolerability profile. Additional data analyses and pt follow up are ongoing and will be presented at the conference. Data extract 01/24/2023. 1. Moroney JW, Yeku O et al. Triple blockade of the DNAM-axis with COM701 + BMS-986207 + nivolumab demonstrates preliminary antitumor activity in patients with platinum resistant OVCA. Annals of Oncology (2022) 16 (suppl_1): 100104-100104. 10.1016/iotech/iotech100104. Clinical trial information: NCT04570839 .

Phase 2 trial of retifanlimab (anti–PD-1) in combination with INCAGN02385 (anti–LAG-3) and INCAGN02390 (anti–TIM-3) as first-line treatment in patients with PD-L1–positive recurrent/metastatic squamous cell carcinoma of the head and neck.

TPS6104 Background: Anti–PD-(L)1 therapies have improved clinical outcomes in PD-L1+ squamous cell carcinoma of the head and neck (SCCHN). However, many patients either do not respond or develop resistance, partly due to additional immune checkpoint receptors including LAG-3 and TIM-3, which are frequently coexpressed with PD-1 on tumor-infiltrating lymphocytes. In preclinical studies, LAG-3 and TIM-3 blockade showed synergistic activity with PD-1 inhibition, and triple blockade improves T-cell reinvigoration and antitumor efficacy over single/double combinations. Emerging clinical evidence also supports blockade of PD-1, LAG-3, and TIM-3 as a promising combination approach in checkpoint inhibitor–naive patients. This study aims to assess the efficacy and safety of the anti–PD-1 antibody, retifanlimab, in combination with INCAGN02385 (anti–LAG-3) and INCAGN02390 (anti–TIM-3) antibodies as first-line treatment in PD-L1+ recurrent or metastatic SCCHN. Methods: This randomized, double-blind, multicenter, phase 2 study (NCT05287113) includes patients with previously untreated, recurrent or metastatic, PD-L1+ (combined positive score [CPS] ≥1%) SCCHN and ECOG status of 0 or 1. Approximately 162 patients will be randomized 1:1:1 to receive (1) intravenous (IV) retifanlimab 500 mg every 4 weeks (Q4W) plus placebo controls, (2) retifanlimab plus IV INCAGN02385 350 mg Q2W plus placebo, or (3) retifanlimab plus INCAGN02385 plus IV INCAGN02390 400 mg Q2W. Patients will be stratified at randomization by LAG-3 expression (tumor proportion score ≥5% vs < 5%), PD-L1 CPS (1%-19% vs ≥20%), and human papillomavirus p16 status (positive vs negative; oropharyngeal tumors only). Treatment will be administered in 4-week cycles for up to 2 years. The primary endpoint is progression-free survival (PFS; defined per Response Evaluation Criteria in Solid Tumors [RECIST] v1.1). Secondary endpoints are objective response rate per RECIST v1.1, duration of response, disease control, overall survival, and safety. Sample size calculation is based on a median PFS of 3 months, based on historical data for anti–PD-1 monotherapy in the first-line treatment setting for PD-(L)1+ advanced/metastatic SCCHN. PFS, overall survival, and duration of response data will be analyzed by the Kaplan-Meier method. Patient enrollment is ongoing. Clinical trial information: NCT05287113 .

Pharmacological conversion of gut epithelial cells into insulin-producing cells lowers glycemia in diabetic animals.

As a highly regenerative organ, the intestine is a promising source for cellular reprogramming for replacing lost pancreatic β cells in diabetes. Gut enterochromaffin cells can be converted to insulin-producing cells by forkhead box O1 (FoxO1) ablation, but their numbers are limited. In this study, we report that insulin-immunoreactive cells with Paneth/goblet cell features are present in human fetal intestine. Accordingly, lineage-tracing experiments show that, upon genetic or pharmacologic FoxO1 ablation, the Paneth/goblet lineage can also undergo conversion to the insulin lineage. We designed a screening platform in gut organoids to accurately quantitate β-like cell reprogramming and fine-tune a combination treatment to increase the efficiency of the conversion process in mice and human adult intestinal organoids. We identified a triple blockade of FOXO1, Notch, and TGF-β that, when tested in insulin-deficient streptozotocin (STZ) or NOD diabetic animals, resulted in near normalization of glucose levels, associated with the generation of intestinal insulin-producing cells. The findings illustrate a therapeutic approach for replacing insulin treatment in diabetes.

158P Triple blockade of the DNAM-axis with COM701 + BMS-986207 + nivolumab demonstrates preliminary antitumor activity in patients with platinum-resistant OVCA

Treatment [tx] options for platinum-resistant ovarian cancer [PROC] are limited [ltd]. Immune checkpoint inhibitors (ICI) have ltd activity in PROC. Clinical studies evaluating novel therapies are urgently needed. COM701, a novel, 1st in-class ICI binds to PVRIG, leading to activation of T-cells. BMS-986207 is an ICI blocker of TIGIT. We reported a partial response [PR] with COM701 monotherapy in a pt with primary peritoneal CA1. We hypothesized that in pts with PROC, blocking the DNAM axis with the triplet: COM701 + BMS-986207 + nivolumab, would demonstrate antitumor activity with a favorable safety and tolerability profile.

Triple blockade of Ido-1, PD-L1 and MEK as a potential therapeutic strategy in NSCLC

BackgroundDespite the recent progress in the treatment and outcome of Non Small Cell Lung Cancer (NSCLC), immunotherapy has still significant limitations reporting a significant proportion of patients not benefiting from therapy, even in patients with high PD-L1 expression. We have previously demonstrated that the combined inhibition of MEK and PD-L1 in NSCLC patients derived three dimensional cultures exerted significant synergistic effect in terms of immune-dependent cancer cell death. However, subsequent experiments analyzing the expression of Indoleamine 2,3-dioxygenase-1 (Ido-1) gene expression demonstrated that Ido-1 resulted unaffected by the MEK inhibition and even increased after the combined inhibition of MEK and PD-L1 thus representing a potential escape mechanism to this combination.MethodsWe analyzed transcriptomic profile of NSCLC lung adenocarcinoma cohort of TCGA (The Cancer Genome Atlas), stratifying tumors based on EMT (Epithelial mesenchymal Transition) score; in parallel, we investigated the activation of Ido-1 pathway and modulation of immune cytokines productions both in NSCLC cells lines, in peripheral blood mononuclear cells (PBMCs) and in ex-vivo NSCLC spheroids induced by triple inhibition with an anti-PD-L1 monoclonal antibody, the MEK inhibitor and the Ido-1 inhibitor.ResultsIn NSCLC lung adenocarcinoma patient cohort (from TCGA) Ido-1 gene expression was significantly higher in samples classified as mesenchymal according EMT score. Similarly, on a selected panel of NSCLC cell lines higher expression of MEK and Ido-1 related genes was detected in cells with mesenchymal phenotype according EMT score, thus suggesting a potential correlation of co-activation of these two pathways in the context of EMT, with cancer cells sustaining an immune-suppressive microenvironment. While exerting an antitumor activity, the dual blockade of MEK and PD-L1 enhances the secretion of pro-inflammatory cytokines (IFNγ, TNFα, IL-12 and IL-6) and, consequently, the expression of new immune checkpoints such as Ido-1. The triple inhibition with an anti-PD-L1 monoclonal antibody, the MEK inhibitor and the Ido-1 inhibitor demonstrated significant antiproliferative and proapoptotic activity on ex-vivo NSCLC samples; at the same time the triple combination kept increased the levels of pro-inflammatory cytokines produced by both PBMCs and tumor spheroids in order to sustain the immune response and simultaneously decreased the expression of other checkpoint (such as CTLA-4, Ido-1 and TIM-3) thus promoting an immune-reactive and inflamed micro-environment.ConclusionsWe show that Ido-1 activation is a possible escape mechanism to immune-mediated cell death induced by combination of PD-L1 and MEK inhibitors: also, we show that triple combination of anti-PD-L1, anti-MEK and anti-Ido-1 drugs may overcome this negative feedback and restore anti-tumor immune response in NSCLC patients’ derived three dimensional cultures.

705TiP Phase II trial of retifanlimab (anti–PD-1) in combination with INCAGN02385 (anti–LAG-3) and INCAGN02390 (anti-TIM-3) as first-line treatment in patients with PD-L1-positive recurrent/metastatic squamous cell carcinoma of the head and neck

Anti-PD-(L)1 therapies have improved clinical outcomes in PD-L1+ squamous cell carcinoma of the head and neck (SCCHN). However, many patients either do not respond or develop resistance, partly due to additional immune checkpoint receptors including LAG-3 and TIM-3, which are frequently coexpressed with PD-1 in tumor infiltrating lymphocytes. In preclinical studies, LAG-3 and TIM-3 blockade showed synergistic activity with PD-1 inhibition, and triple blockade improves T-cell reinvigoration and antitumor efficacy over single/double combinations. Emerging clinical evidence also supports blockade of PD-1, LAG-3, and TIM-3 as a promising combination approach in checkpoint inhibitor-naive patients. This study aims to assess the efficacy and safety of the anti–PD-1 antibody retifanlimab in combination with INCAGN02385 (anti–LAG3) and INCAGN02390 (anti–TIM-3) antibodies as first-line treatment in PD-L1+ recurrent or metastatic SCCHN. This randomized, double-blind, multicenter, phase 2 study (NCT05287113) includes patients with previously untreated, recurrent or metastatic, PD-L1+ (combined positive score (CPS) ≥1%) SCCHN and Eastern Cooperative Oncology Group (ECOG) status of 0 or 1. Approximately 162 patients will be randomized 1:1:1 to receive (1) intravenous (IV) retifanlimab 500 mg every 4 weeks (Q4W) plus placebo controls, (2) retifanlimab plus IV INCAGN02385 350 mg Q2W plus placebo, or (3) retifanlimab plus INCAGN02385 plus IV INCAGN02390 400 mg Q2W. Patients will be stratified at randomization by LAG-3 expression (tumor proportion score ≥5% vs <5%), PD-L1 CPS (1%–19% vs ≥20%), and human papillomavirus p16 status (positive vs negative; oropharyngeal tumors only). Treatment will be administered in 4-week cycles for up to 2 years. The primary endpoint is progression-free survival (defined per Response Evaluation Criteria in Solid Tumors [RECIST] v1.1). Secondary endpoints are objective response per RECIST v1.1, duration of response, disease control, overall survival and safety. NCT05287113. Writing assistance was provided by Cory Pfeiffenberger, PhD (ICON, Blue Bell, PA, USA). Incyte Corporation.

CD8+ T-cell Responses Are Boosted by Dual PD-1/VEGFR2 Blockade after EGFR Inhibition in Egfr-Mutant Lung Cancer.

Epidermal growth factor receptor (EGFR) is the most frequently mutated driver oncogene in nonsmoking-related, non-small cell lung cancer (NSCLC). EGFR-mutant NSCLC has a noninflamed tumor microenvironment (TME), with low infiltration by CD8+ T cells and, thus, immune-checkpoint inhibitors, such as antiprogrammed cell death-1 (anti-PD-1), have weak antitumor effects. Here, we showed that CD8+ T-cell responses were induced by an EGFR-tyrosine kinase inhibitor (TKI) in syngeneic Egfr-mutant NSCLC tumors, which was further pronounced by the sequential dual blockade of PD-1 and vascular endothelial growth factor receptor 2 (VEGFR2). However, the simultaneous triple blockade had no such effect. The PD-1/VEGFR2 dual blockade did not exert tumor-inhibitory effects without pretreatment with the EGFR-TKI, suggesting that the treatment schedule is crucial for the efficacy of the dual blockade therapy. Pretreatment with EGFR-TKI increased the CD8+ T-cell/regulatory T-cell (Treg) ratio, while also increasing the expression of immunosuppressive chemokines and chemokine receptors, as well as increasing the number of M2-like macrophages, in the TME. Discontinuing EGFR-TKI treatment reversed the transient increase of immunosuppressive factors in the TME. The subsequent PD-1/VEGFR2 inhibition maintained increased numbers of infiltrating CD8+ T cells and CD11c+ dendritic cells. Depletion of CD8+ T cells in vivo abolished tumor growth inhibition by EGFR-TKI alone and the sequential triple therapy, suggesting that EGFR inhibition is a prerequisite for the induction of CD8+ T-cell responses. Our findings could aid in developing an alternative immunotherapy strategy in patients with cancers that have driver mutations and a noninflamed TME.

Cancer combination therapies by silencing of CTLA-4, PD-L1, and TIM3 in osteosarcoma.

Osteosarcoma (OS) is the most common orthopedic neoplasm, with a high metastasis rate and a dismal prognosis despite surgery and chemotherapy. Immunotherapies have offered cancer patients a ray of optimism, but their impact on OS has been disappointing. The objective of this study is to assess the effect of mono, dual, and triple combinations of CTLA-4, PD-L1, and TIM3 blockade on OS cell viability, apoptosis, and migration. The MG-63 and U-2 OS cell lines were transfected with mono, dual, and triple combinations of siRNAs specific for CTLA-4, PD-L1, and TIM3. After evaluation for transfection efficacy by qRT-PCR, MTT assay and flow cytometry were applied to assess cell viability and apoptosis rate in siRNA-transfected cells, respectively. Ultimately, the migration of transfected cells was measured by wound-healing assay. First, the qRT-PCR analysis revealed that in siRNA-transfected OS cells, CTLA-4, PD-L1, and TIM3 were downregulated. The MTT assay and flow cytometry results confirmed that silencing of these immune checkpoints in dual or triple combinations, but not in the single-agent blockade, significantly decreases cell viability and increases apoptosis, respectively. These effects were more significant when triple silencing was performed. Finally, the wound-healing assay revealed that dual and triple silencing of immune checkpoints significantly inhibits cell migration, with triple silencing exhibiting a greater effect. Our findings suggest that triple blockade of CTLA-4, PD-L1, and TIM3 is an effective strategy for inhibiting tumor cell progression and migration in OS, which requires large-scale clinical investigations to be translated into broad therapeutic applicability for OS patients.

Abstract 3608: Triple checkpoint blockade, but not anti-PD1 alone, enhances the efficacy of engineered adoptive T cell therapy in advanced ovarian cancer

Abstract Background: Less than half of ovarian cancer patients survive five years after diagnosis. This rate has changed little in the last 30 years, highlighting the need for novel therapies. A promising new strategy with the potential to control tumor growth without toxicity to healthy tissues employs immune T cells engineered to target proteins uniquely overexpressed in tumors. Mesothelin (Msln) is overexpressed in high grade serous 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 murine ovarian tumor cells in vitro and in vivo. Tumor-bearing mice were treated with TCRMsln T cells plus anti-PD-1, anti-Tim-3 or anti-Lag-3 checkpoint-blocking antibodies administered alone or in combination, ultimately allowing targeting up to three inhibitory receptors simultaneously. Single cell RNA sequencing was used to profile the impact of combination checkpoint blockade on both the engineered T cells and the tumor microenvironment. Results: In a disseminated ID8 tumor model, adoptively transferred TCRMsln T cells preferentially accumulated within established tumors, delayed ovarian tumor growth, and significantly prolonged mouse survival. However, our data also revealed that elements in the tumor microenvironment (TME) limited engineered T cell persistence and ability to kill cancer cells. Triple checkpoint blockade, but not single- or double-agent treatment, dramatically increased effector cytokine production by intratumoral TCRMsln T cells. Single cell RNA-sequencing revealed gene expression changes in engineered T cells and myeloid cells in the TME consistent with activation and inflammation. Moreover, combining adoptive immunotherapy with triple checkpoint blockade prolonged survival in the cohort of treated tumor-bearing mice, relative to TCRMsln with or without anti-PD1, or double-agent treatments. Conclusions: Inhibitory receptor/ligand interactions within the tumor microenvironment can dramatically reduce T cell function, suggesting tumor cells may increase expression of the ligands for PD-1, Tim-3 and Lag-3 for protection from tumor-infiltrating lymphocytes. In a model of advanced ovarian cancer, triple checkpoint blockade significantly improved the anti-tumor function of transferred engineered T cells and improved outcomes in mice in a setting in which single checkpoint blockade had no significant activity. These results suggest that disrupting multiple inhibitory signaling pathways simultaneously, which can be more safely pursued 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, Aesha Vakil, Valentin Voillet, Raphael Gottardo, Philip 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 American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3608.

Abstract 5516: Nanoparticle-enhanced radiotherapy combined with triple blockade of PD1, LAG3, and TIGIT enhances anti-tumor immune activation

Abstract Introduction: Checkpoint inhibition (CPI) has been a game-changer for cancer therapy, but most cancers do not respond. Part of the problem is that cancers employ multiple checkpoints; thus, targeting multiple checkpoint receptors simultaneously may yield increased benefit. Previously, we found that radiotherapy (XRT) in concert with a radiation-enhancing nanoparticle (NBTXR3) and PD1 blockade significantly improved tumor control both at the irradiative site and in remote, unirradiated tumors in a mouse model of anti-PD1 (αPD1)-resistant lung cancer (344SQR). Here, we tested whether blockade of TIGIT, LAG3, and PD1 in combination with NBTXR3-enhanced XRT could improve antitumor immune responses in our 344SQR tumor model. Methods: Fifty thousand 344SQR cells were inoculated in the right and left hindlimbs of 129Sv/Ev mice on day 0 and day 4 to establish primary and secondary tumors, respectively. Mice were divided into six treatment groups: 1) untreated; 2) XRT+αPD1; 3) NBTXR3+XRT+αPD1; 4) NBTXR3+XRT+αPD1+αLAG3; 5) NBTXR3+XRT+αPD1+αTIGIT; and 6) NBTXR3+XRT+αPD1+αLAG3 +αTIGIT. Primary tumors were intratumorally injected with NBTXR3 nanoparticles on day 7 and received 3 fractions of 12 Gy X-ray radiation on days 8, 9, and 10. Immune checkpoint inhibitors, composed of αPD1 (200 μg), αLAG3 (200 μg), and αTIGIT (200 μg), were intraperitoneally administered to the mice on days 5, 8, 11, 14. The expression of 770 immune-related genes were measured via NanoString from the RNA extracted from the primary and secondary tumors on day 21. Results: CPIs+NBTXR3-enhanced radiation significantly promoted the upregulation of mRNA transcripts involved in innate immunity, the humoral response, B cell function, dendritic cell (DC) function, and antigen processing within primary, irradiated tumors relative to untreated controls. No additional increase in immune gene activity in the irradiated tumors was observed when LAG3, TIGIT, or both were blocked in addition to PD1. However, within the non-irradiated tumors, triple blockade of PD1, LAG3, and TIGIT in concert with NBTXR3+XRT produced elevations in multiple immune-related pathways that were significantly higher than those produced by other treatment combinations. These pathways included both adaptive and innate immunity; B, T, and natural killer (NK) cell, and DC function; and antigen processing. Conclusions: Simultaneous inhibition of LAG3 and TIGIT in tandem with PD1 blockade and NBTXR3-enhanced radiotherapy promotes immune activation at the irradiated site. In addition, abscopal immune responses are improved with blockade of LAG3 and TIGIT. These results suggest that blockade of multiple immune checkpoints in parallel with NBTXR3-mediated radiotherapy may be effective in metastatic cancers. [Y.H. and B.G. contributed equally to this work.] Citation Format: Yun Hu, Genevieve Bertolet, Sebastien Paris, Hampartsoum Barsoumian, Jordan DA SILVA, Saumil Gandhi, Quynh-Nhu Nguyen, Maria A. Cortez, James W. Welsh. Nanoparticle-enhanced radiotherapy combined with triple blockade of PD1, LAG3, and TIGIT enhances anti-tumor immune activation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5516.

Abstract OT2-20-01: Rogaratinib, palbociclib and fulvestrant in advanced hormone receptor-positive (HR+), FGFR1/2-positive breast cancer: Phase I trial plus an expansion cohort

Abstract Background: Novel therapies are needed upon progression to first-line CDK4/6 inhibitor (CDKi) plus endocrine therapy in advanced HR+ breast cancer. One frequent alteration driving resistance to CDKi plus hormones is FGFR1/2 amplification/overexpression. We have demonstrated that a combined assay of RNAScope and FISH, detecting RNA overexpression and genomic amplification of FGFR1/2, captures more FGFR-aberrant cases than either test alone. When these alterations exist, the triple estrogen receptor (ER), CDK4/6 and FGFR1/2 blockade is able to revert acquired resistance to CDKi (Breast Cancer Res; 23:21-37; 2021). Rogaratinib is a selective FGFR1-4 kinase inhibitor with significant activity in FGFR-aberrant malignancies. In this trial we will test the safety of the triple blockade combining fulvestrant, palbociclib and rogaratinib. We will also study its role as a resistant-reversion combo for FGFR1/2-positive, HR+ patients progressing to a CDK4/6 inhibitor plus aromatase inhibitor (AI) in the first-line metastatic setting. Trial design: Single-arm, prospective, multicentric, open-label, phase I dose-escalation trial. Patients will be pre-screened for amplification and/or overexpression of FGFR1/2 by FISH and RNAScope, during their first-line treatment. Positive patients will start treatment: on day 1, patients will receive rogaratinib q12 hours. On day 2, patients will continue on rogaratinib, receive fulvestrant (500 ug IM) and start on palbociclib (100 mg/day on days 1-21). A second fulvestrant dose (500 ug) will be administered in day +15. The first cycle will be 29 days, followed by 28-day cycles (continuous rogaratinib q12 hours days 1-28, fulvestrant 500 ug day 1, and palbociclib 100 mg/day days 1-21). Rogaratinib will be escalated, starting on 400 mg/bid in 200 mg/bid increments, following a classic 3+3 schedule. Patients experiencing ≤ grade 1 tolerable side effects as the greatest toxicity will be allowed to escalate palbociclib to 125 in cycle 2. A full pharmacokinetic profile and pharmacodynamics (plasma FGF23 and phosphate levels) will be performed on days 1 and 15 of cycle 1. The impact of the triple combination in immunodynamics will be assessed on PBMCs on days 2 and 15. Ten additional HR+, FGFR1/2 + patients will be accrued at the RP2D in an expansion cohort to study efficacy. RECIST 1.1 and NCI CTC AE V 5.0 criteria will be used for assessing disease control (q8 weeks) and toxicity. Eligibility criteria: Pre-screening: Women &amp;gt;18 year old diagnosed with advanced, non-curable HR+ breast cancer; 2) who are receiving first-line treatment with an AI and any oral CDKi; 3) Adequate organ function. Full screening: 4) Positivity for amplification (FISH ratio&amp;gt;2.2) and/or overexpression (RNAScope score of 3+ or 4+) of either FGFR1/2. 5) PD to first-line AI + CDKi within the last 28 days. 6) Recovery from previous toxicity to &amp;lt; tolerable G2. Specific aims: Primary: 1) To determine RP2D of the triple combination of fulvestrant, palbociclib and rogaratinib. 2) To assess the safety and toxicity of the former combination 3) To study the pharmacokinetics, pharmacodynamics and immunodynamics of the triplet. Secondary: 1) To determine the PFS time and 6-month PFS rate of the triplet in FGFR1/2 amplified/overexpressed patients AI + CDKi doublet. Statistical methods: We will follow a 3+3 escalation schedule; thus, the minimum and maximum number of patients for the dose-escalation phase will range between 6 and 18 (no escalation planned beyond 800 mg/bid rogaratinib). Ten additional patients will be accrued in the expansion cohort (N=28). The anticipated rate of positive screening is 40%; thus, we will screen approximately 70 patients. . Present accrual/target accrual: 55/70 screened; 16 FGFR1/2-positive (of 28 planned); 2 accrued and treated. Citation Format: Sonia Pernas, Cristina Hernando, Begoña Bermejo, Noelia Martinez-Jañez, Jose A García Saenz, Serafin Morales, Luis Manso, Jorge Silva, Juan A Guerra, Diego Malon, Silvana Mouron, Eduardo Caleiras, Miguel Quintela-Fandino. Rogaratinib, palbociclib and fulvestrant in advanced hormone receptor-positive (HR+), FGFR1/2-positive breast cancer: Phase I trial plus an expansion cohort [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr OT2-20-01.

Single, Double and Triple Blockade of RAAS in Alport Syndrome: Different Tools to Freeze the Evolution of the Disease.

Background: The goal of the treatment of Alport syndrome (AS) is to delay the progression of kidney damage. The current standard of care is the use of Renin Angiotensin Aldosterone System (RAAS) blockers: angiotensin-converting enzyme inhibition (ACEi), angiotensin receptor blockade, and, recently, spironolactone (SP). Aim of the study: the purpose of this retrospective study is to evaluate the efficacy (reduction of proteinuria and changes of glomerular function) and safety of a sequential introduction of RAAS blockers up to a triple RAAS blockade in pediatric proteinuric patients with AS. Methods: in this retrospective study (1995 to 2019), we evaluated proteinuria values in AS patients, during the 12 months following the beginning of a new RAAS blocker, up to a triple blockade. ACEi was always the first line of treatment; then ARB and SP were sequentially added if uPCR increased by 50% from the basal level in 2 consecutive samples during a 3-months observation period, or when uPCR ratio was >2 mg/mg. Results: 26 patients (mean age at treatment onset was 10.55 ± 5.02 years) were enrolled. All patients were on ACEi, 14/26 were started on a second drug (6/14 ARB, 8/14 SP) after a mean time of 2.2 ± 1.7 years, 7/26 were on triple RAAS blockade after a further period of 5.5 ± 2.3 years from the introduction of a second drug. Repeated Measure Anova analysis of log-transformed data shows that the reduction of uPCR values after Time 0 from the introduction of the first, second and third drug is highly significant in all three cases (p values = 0.0016, 0.003, and 0.014, respectively). No significant changes in eGFR were recorded in any group, apart from a 15-year-old boy with X-linked AS, who developed kidney failure. One patient developed mild hyperkaliemia, and one gynecomastia and symptomatic hypotension. No life-threatening events were recorded. Conclusions: double and triple RAAS blockade is an effective and safe strategy to reduce proteinuria in children with AS. Nevertheless, we suggest monitoring eGFR and Kaliemia during follow-up.

Clinical and anamnestic characteristics of patients with an implanted cardioverter-defibrillator in real clinical practice (data from the Kuzbass register)

Aim To study the consistency of the practice of management, selection and routing of patients at high risk of sudden cardiac death (SCD) selected for cardioverter-defibrillator implantation (CDI) with current clinical guidelines and to evaluate the quality of subsequent outpatient follow-up and treatment based on a retrospective analysis of clinical amnestic data from the Kuzbass Registry of Patients with CDI.Material and methods The study was based on the Registry of Patients with Implanted Cardioverter Defibrillator and included successive data of 28 patients hospitalized to the Kizbass Cardiological Center from 2015 through 2019. Social and clinical amnestic characteristics, indications for CVI, and concomitant drug therapy were analyzed retrospectively. Statistical analyses were performed with the Statistica 10.0 software (Statsoft, USA).Results Median age of patients was 59 (53; 66) years; 239 (83.6 %) men were included; 29 (10.1%) people were employed, CHI was performed in 182 (63.6 %) patients for prevention of SCC, and for secondary prevention in 104 (36.4 %) patients. 208 (72.7 %) patients were diagnosed with ischemic heart disease (IHD), and 145 (67.9 %) of them underwent myocardial revascularization. Noncoronarogenic diseases were found in 78 (27.3 %) patients, and most of them were diagnosed with dilated cardiomyopathy. All patients had chronic heart failure (CHF); half of them had stage IIA CHF. Median left ventricular ejection fraction was 30 (25; 36,5) % according to echocardiography using the Simpson method. Comorbidity was found in 151 (52.8 %) patients. 128 (44.8%) patients received a triple neurohormonal blockade for CHF treatment; titration to target doses was not performed in any of them. Antiarrhythmics were administered to 150 (52.4 %) patients.Conclusion According to the data from the Kuzbass Registry of CVI, the main patient cohort consisted of men of pension age with IHD and CHF. Before CVI, more than a half of them had not received an optimum drug therapy and not all of them had received target lesion revascularization. Creating and analysis of Registries of CHI patients is an effective method for identifying existing problems in patient management before CVI and for optimizing their subsequent follow-up and treatment.

FGFR1 amplification or overexpression and hormonal resistance in luminal breast cancer: rationale for a triple blockade of ER, CDK4/6, and FGFR1

BackgroundFGFR1 amplification, but not overexpression, has been related to adverse prognosis in hormone-positive breast cancer (HRPBC). Whether FGFR1 overexpression and amplification are correlated, what is their distribution among luminal A or B HRPBC, and if there is a potential different prognostic role for amplification and overexpression are currently unknown features. The role of FGFR1 inhibitors in HRPBC is also unclear.MethodsFGFR1 amplification (FISH) and overexpression (RNAscope) were investigated in a N = 251 HRPBC patients cohort and the METABRIC cohort; effects on survival and FISH-RNAscope concordance were determined. We generated hormonal deprivation resistant (LTED-R) and FGFR1-overexpressing cell line variants of the ER+ MCF7 and T47-D and the ER+, FGFR1-amplified HCC1428 cell lines. The role of ER, CDK4/6, and/or FGFR1 blockade alone or in combinations in Rb phosphorylation, cell cycle, and survival were studied.ResultsFGFR1 overexpression and amplification was non-concordant in > 20% of the patients, but both were associated to a similar relapse risk (~ 2.5-fold; P < 0.05). FGFR1 amplification or overexpression occurred regardless of the luminal subtype, but the incidence was higher in luminal B (16.3%) than A (6.6%) tumors; P < 0.05. The Kappa index for overexpression and amplification was 0.69 (P < 0.001). Twenty-four per cent of the patients showed either amplification and/or overexpression of FGFR1, what was associated to a hazard ratio for relapse of 2.6 (95% CI 1.44–4.62, P < 0.001). In vitro, hormonal deprivation led to FGFR1 overexpression. Primary FGFR1 amplification, engineered mRNA overexpression, or LTED-R-acquired FGFR1 overexpression led to resistance against hormonotherapy alone or in combination with the CDK4/6 inhibitor palbociclib. Blocking FGFR1 with the kinase-inhibitor rogaratinib led to suppression of Rb phosphorylation, abrogation of the cell cycle, and resistance-reversion in all FGFR1 models.ConclusionsFGFR1 amplification and overexpression are associated to similar adverse prognosis in hormone-positive breast cancer. Capturing all the patients with adverse prognosis-linked FGFR1 aberrations requires assessing both features. Hormonal deprivation leads to FGFR1 overexpression, and FGFR1 overexpression and/or amplification are associated with resistance to hormonal monotherapy or in combination with palbociclib. Both resistances are reverted with triple ER, CDK4/6, and FGFR1 blockade.

Abstract PR02: Melanoma evolves complete immunotherapy resistance through acquisition of a hypermetabolic phenotype

Abstract Advances in our understanding of tumor immune biology and development of cancer immunotherapies have led to improved outcomes for patients who suffer from aggressive cancers such as melanoma. Despite the clinical success of immune checkpoint blockade, a majority of patients still fail to respond, and the underlying mechanisms that drive resistance remain unclear. To understand why a subset of tumors fail to respond to immunotherapy, we established a novel murine model of melanoma that is fully resistant to immune checkpoint blockade. By in vivo passaging nonresponding B16 melanoma tumor cells, we selected for a resistant variant that fails to respond to the combination of CTLA-4, PD-1, and PD-L1 blockade. In comparing gene expression of parental versus resistant tumor cells and analyzing the corresponding immune infiltrate, we determined the adaptations associated with resistance to therapy. We found that evasion of immunotherapy was associated with a “hypermetabolic” phenotype, characterized by an upregulation of glycolytic, oxidoreductase, and mitochondrial oxidative phosphorylation pathways to establish a hypoxic, metabolically hostile microenvironment. Enforced expression of two key genes associated with these pathways in parental tumor cells was sufficient to mediate resistance to triple checkpoint blockade. Flow cytometry assays determined that T cells infiltrating resistant tumors had diminished glycolytic capacity and effector function, indicating a metabolic disadvantage. Consistent with our findings, melanoma patients who failed dual checkpoint blockade exhibited similar metabolic alterations as seen in our resistant variant. Using a novel MRI-based imaging approach, we observed distinct metabolic changes that stratified responding versus nonresponding tumors in live mice. Applying this method to patients could provide insight into predicting response rates to checkpoint modulation. Overall, our data indicate that resistant melanoma tumor cells acquire a “hypermetabolic” phenotype to establish a hostile microenvironment that is capable of inhibiting the antitumor immune response. This abstract is also being presented as Poster A24. Citation Format: Ashvin R. Jaiswal, Arthur J. Liu, Shivanand Pudakalakatti, Prasanta Dutta, Priyamvada Jayaprakash, Todd Bartkowiak, Casey Ager, Zhiqiang Wang, Alex Reuben, Zachary Cooper, Cristina Ivan, Zhenlin Ju, Felix Nwajei, Jing Wang, Michael A. Davies, R. Eric Davis, Jennifer A. Wargo, Pratip K. Bhattacharya, David S. Hong, Michael A. Curran. Melanoma evolves complete immunotherapy resistance through acquisition of a hypermetabolic phenotype [abstract]. In: Proceedings of the AACR Special Conference on Melanoma: From Biology to Target; 2019 Jan 15-18; Houston, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(19 Suppl):Abstract nr PR02.

Triple blockade of EGFR, MEK and PD-L1 has antitumor activity in colorectal cancer models with constitutive activation of MAPK signaling and PD-L1 overexpression

BackgroundMolecular mechanisms driving acquired resistance to anti-EGFR therapies in metastatic colorectal cancer (mCRC) are complex but generally involve the activation of the downstream RAS-RAF-MEK-MAPK pathway. Nevertheless, even if inhibition of EGFR and MEK could be a strategy for overcoming anti-EGFR resistance, its use is limited by the development of MEK inhibitor (MEKi) resistance.MethodsWe have generated in vitro and in vivo different CRC models in order to underline the mechanisms of MEKi resistance.ResultsThe three different in vitro MEKi resistant models, two generated by human CRC cells quadruple wild type for KRAS, NRAS, BRAF, PI3KCA genes (SW48-MR and LIM1215-MR) and one by human CRC cells harboring KRAS mutation (HCT116-MR) showed features related to the gene signature of colorectal cancer CMS4 with up-regulation of immune pathway as confirmed by microarray and western blot analysis. In particular, the MEKi phenotype was associated with the loss of epithelial features and acquisition of mesenchymal markers and morphology. The change in morphology was accompanied by up-regulation of PD-L1 expression and activation of EGFR and its downstream pathway, independently to RAS mutation status. To extend these in vitro findings, we have obtained mouse colon cancer MC38- and CT26-MEKi resistant syngeneic models (MC38-MR and CT26-MR). Combined treatment with MEKi, EGFR inhibitor (EGFRi) and PD-L1 inhibitor (PD-L1i) resulted in a marked inhibition of tumor growth in both models.ConclusionsThese results suggest a strategy to potentially improve the efficacy of MEK inhibition by co-treatment with EGFR and PD-L1 inhibitors via modulation of host immune responses.

11P - Triple blockade of EGFR, MEK and PD-L1 as effective antitumor treatment in PD-L1 overexpressing, MEK inhibitor resistant colon cancer cells

BackgroundMolecular mechanisms driving acquired resistance to anti-EGFR therapies in metastatic Colorectal Cancer (mCRC) are complex but generally involve the activation of the downstream RAS-RAF-MEK-MAPK pathway. MethodsIn order to understand the mechanism underlying MEK inhibitor (MEKi) resistance, we generated three different MEKi resistant models, two all RAS WT (SW48-MR and LIM1215-MR) and one mutated in RAS (HCT116-MR). ResultsThese models showed features related to the gene signature of Colorectal Cancer CMS4 with upregulation of immune pathway as confirmed by Microarray and Western blot analysis. In particular, moving forward the MEKi phenotype we assisted to the loss of epithelial features and acquisition of mesenchymal markers and morphology. Moreover, this change in the morphology is accompanied by up-regulation of PD-L1 expression and activation of EGFR and its downstream pathway, independently of cell line status mutation. To extend these in vitro findings, we performed an in vivo study using MC38 and CT26 MEKi resistant syngeneic models that we have previously generated. Combined treatment of MEKi, EGFR inhibitor (EGFRi) and PD-L1inhibitor (PD-L1i) resulted in a marked inhibition of tumor growth in both MC38–MR and CT26-MR xenograft model. ConclusionsThese results suggest a strategy to potentially overcome immunotherapy resistance in CMS4-like tumors and to improve the efficacy of MEK inhibition by co-treatment with other agents providing an additional therapeutic strategy via modulation of host immune responses. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.

Abstract 3208: Using T cell engineering plus triple checkpoint blockade to enhance the efficacy of adoptive immunotherapy in ovarian cancer

Abstract Over 20,000 women are diagnosed with ovarian cancer in the United States annually, and over half will die within 5 years. Outcomes have changed little in the last 20 years, highlighting the need for therapy innovation. One promising new strategy employs immune T cells engineered to target proteins uniquely overexpressed in tumors; such T cell immunotherapies have the potential to control tumor growth without toxicity to healthy tissues. In considering candidate immunotherapy targets, we focused on mesothelin (MSLN), which contributes to invasive progression and malignancy in ovarian cancer but has limited expression in healthy cells. We showed that T cells engineered to express a human or mouse MSLN-specific high-affinity T cell receptor (TCRMSLN) can kill human patient-derived ovarian cancer cell lines or the murine ID8 cell line, respectively. In a disseminated ID8 tumor model, adoptively transferred TCRMSLN T cells preferentially accumulated within established tumors, delayed ovarian tumor growth, and significantly prolonged mouse survival. However, our data also revealed that the ovarian tumor microenvironment (TME) limits engineered T cell persistence and cancer cell killing. To identify immunosuppressive features active in both the human and murine ovarian TME, we performed gene expression analyses. Deep transcriptome profiling confirmed similar gene expression signatures in human cancers and in the preclinical ID8 model. Among these, RNA sequencing detected PD-L1, Galectin-9 and Galectin-3, ligands for CD8 T cell-expressed PD-1, Tim-3 and Lag-3 ‘checkpoint’ receptors, respectively. We also measured PD-L1, Galectin-9 and Galectin-3 expression in human and mouse ovarian cancers by flow cytometry and immunohistochemistry, and multiplex immunohistochemistry of human ovarian tumors confirmed the presence of endogenous CD8 T cells expressing one, two or all three inhibitory receptors. Moreover, flow cytometry revealed that TCRMSLN-transduced T cells increase expression of the inhibitory receptors in ID8 tumors relative to cells in the spleen as early as three weeks after transfer, in association with decreased production of anti-tumor cytokines. Based on our results, we hypothesized that we could overcome engineered T cell suppression via inhibitory receptor ligation. We treated tumor-bearing mice with TCRMSLN T cells plus anti-PD-1, anti-Tim-3 and/or anti-Lag-3 checkpoint-blocking antibodies, targeting up to three inhibitory receptors simultaneously. Triple checkpoint blockade dramatically increased anti-tumor cytokine production by intratumoral TCRMSLN T cells. As many solid tumors both overexpress MSLN as well as PD-1, Tim-3 and Lag-3, the use of multi-checkpoint blockade with engineered T cells has real potential to also enhance the efficacy of engineered adoptive T cell therapy against other malignancies. Citation Format: Kristin G. Anderson, Madison G. Burnett, Valentin Voillet, Edison Y. Chiu, Breanna M. Bates, Nicolas M. Garcia, Raphael Gottado, Philip D. Greenberg. Using T cell engineering plus triple checkpoint blockade to enhance the efficacy of adoptive immunotherapy in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3208.