445 Blockade of the inhibitory collagen receptor LAIR-1 with NC410, a LAIR2-Fc fusion protein, enhances anti-tumor activity of the bifunctional fusion protein bintrafusp alfa

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A471-A471
Author(s):  
Lucas Horn ◽  
Linjie Tian ◽  
Dallas Flies ◽  
Linda Liu ◽  
Solomon Langermann ◽  
...  
Keyword(s):  
T Cells ◽  
Fusion Protein ◽  
Tumor Growth ◽  
Transforming Growth Factor ◽  
Immune Cell ◽  
Activated T Cells ◽  
Fc Fusion Protein ◽  
Bifunctional Fusion Protein ◽  
Animal Care

BackgroundLAIR-1 is an immune inhibitory receptor expressed on several immune cell types including activated T cells, B cells, NK cells, macrophages, and dendritic cells. The ligands for LAIR-1 contain collagen-like domains which are commonly found in extracellular matrix collagens and complement component C1q. In numerous cancer types, including gastric, colon, ovarian, bladder, and others, upregulation of collagens has been shown to enhance tumor growth, metastases, and invasion while actively suppressing antitumor immunity. Although humans produce a natural, soluble decoy, LAIR-2, that competes with LAIR-1 for binding of collagen domains, excess LAIR ligands in the tumor often result in an immune suppressive environment.MethodsHere, we report on a novel immunotherapy approach which combined NC410, a LAIR-2-Fc fusion protein capable of blocking LAIR-1 signaling, and bintrafusp alfa, a first-in-class bifunctional fusion protein composed of the extracellular domain of the human transforming growth factor β receptor II (TGF-βRII or TGF-β ‘trap’) fused via a flexible linker to the C-terminus of each heavy chain of an IgG1 antibody blocking programmed death ligand 1 (anti–PD-L1).ResultsWe demonstrate that the combination of NC410 and bintrafusp alfa more effectively controls in vivo tumor growth of the collagen rich MC38 colon carcinoma compared to either monotherapy. We hypothesize that this potent anti-tumor immune response is propagated through the synergy of activated tumor infiltrating lymphocytes and a repolarization of macrophages towards a tumoricidal phenotype. MC38 tumors treated with the combination of NC410/Bintrafusp alfa contained higher numbers of infiltrating CD4+ and CD8+ T cells and higher numbers of CD38+ and MHCII+ M1 polarized macrophages.ConclusionsThis study highlights the synergy of reshaping the large suppressive myeloid cell populations often present in tumors with activation of adaptive T-cell immune responses dampened by checkpoint inhibition. The results also provide the rationale for the future evaluation of this combination therapy in the clinic.AcknowledgementsBintrafusp alfa was kindly provided by EMD Serono under a CRADA with the NCI.Trial RegistrationN/AEthics ApprovalMice were maintained under pathogen-free conditions in accordance with the Association for Assessment and Accreditation of Laboratory Animal Care guidelines. All animal studies were approved by the NIH Intramural Animal Care and Use Committee under protocol LTIB-038.ConsentN/A

Revealing lymphoma growth and the efficacy of immune cell therapies using in vivo bioluminescence imaging

Blood ◽  
2003 ◽  
Vol 101 (2) ◽  
pp. 640-648 ◽  
Author(s):  
Matthias Edinger ◽  
Yu-An Cao ◽  
Michael R. Verneris ◽  
Michael H. Bachmann ◽  
Christopher H. Contag ◽  
...  
Keyword(s):  
T Cells ◽  
Tumor Growth ◽  
Bioluminescence Imaging ◽  
Immune Cell ◽  
Residual Disease ◽  
Cell Therapies ◽  
Nk T Cells ◽  
In Vivo Bioluminescence Imaging ◽  
Minimal Residual

Cancer therapeutics have achieved success in the treatment of a variety of malignancies, however, relapse of disease from small numbers of persistent tumor cells remains a major obstacle. Advancement of treatment regimens that effectively control minimal residual disease and prevent relapse would be greatly accelerated if sensitive and noninvasive assays were used to quantitatively assess tumor burden in animal models of minimal residual disease that are predictive of the human response. In vivo bioluminescence imaging (BLI) is an assay for the detection of small numbers of cells noninvasively and enables the quantification of tumor growth within internal organs. Fusion genes that encode bioluminescent and fluorescent reporter proteins effectively couple the powerful in vivo capabilities of BLI with the subset-discriminating capabilities of fluorescence-activated cell sorting. We labeled 2 murine lymphoma cell lines with dual function reporter genes and monitored radiation and chemotherapy as well as immune-based strategies that employ the tumorcidal activity of ex vivo–expanded CD8+ natural killer (NK)–T cells. Using BLI we were able to visualize the entire course of malignant disease including engraftment, expansion, metastasis, response to therapy, and unique patterns of relapse. We also labeled the effector NK-T cells and monitored their homing to the sites of tumor growth followed by tumor eradication. These studies reveal the efficacy of immune cell therapies and the tempo of NK-T cell trafficking in vivo. The complex cellular processes in bone marrow transplantation and antitumor immunotherapy, previously inaccessible to investigation, can now be revealed in real time in living animals.

scholarly journals 608 Synergistic effect of the combination of ATG-017, an ERK1/2 inhibitor, and immune checkpoint inhibitor in preclinical cancer models

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A638-A638
Author(s):  
Peng Chen ◽  
Yun Liu ◽  
Min Deng ◽  
Jian Wang ◽  
Dirk Hoenemann ◽  
...  
Keyword(s):  
T Cells ◽  
Body Weight ◽  
Tumor Growth ◽  
Cd8 T Cells ◽  
Mapk Pathway ◽  
Clinical Investigation ◽  
Combination Group ◽  
Cancer Models ◽  
Animal Care

BackgroundThe RAS/MAPK pathway has emerged as a critical pathway for therapeutic targeting in a spectrum of solid tumor and hematological malignances. Inhibitors targeting MAPK pathway targets, such as RAS, BRAF, or MEK have been approved for the treatment of cancer either as monotherapy or in combination. However, there has been no approved drug targeting ERK1/2, the terminal kinases in the Ras-Raf-MEK-ERK signal transduction cascade. The combination of ERK1/2 inhibitor and checkpoint inhibitors as therapeutic strategy has not been explored in clinic. ATG-017 is an oral, potent, and highly selective inhibitor of ERK1/2, which is under Phase 1 clinical investigation. ATG-012 is a novel inhibitor of KRAS G12C. In this study, we tested the anti-tumor effect induced by the combination of ATG-017, or ATG-012, and an anti-PDL1 antibody in preclinical cancer models.MethodsWe assessed the anti-cancer effects of ERK1/2, KRAS G12C and PD1/PDL1 inhibition as monotherapy, and as combinations. Anti-PDL1 antibody (atezolizumab), the combination of ATG-012 or ATG-017 and atezolizumab, and the triple combination of atezolizumab, ATG-012 and ATG-017 were tested in a PD(L)1 blockade insensitive syngeneic lung cancer model,LL/2. The ATG-017-atezolizumab combination was also evaluated in a KRAS G13C-mutant,PD(L)1 blockade insensitive lymphoma model, EL4. To further investigate if ERK1/2 inhibition could enhance the efficacy of atezolizumab in a MAPK aberration-independent manner, the ATG-017-atezolizumab combination was tested in a MAPK wild type lymphoma model, A20. As well as assessment of impact on tumor growth, the impact of the drugs on tumor infiltrating leukocytes were analyzed by flow cytometry.ResultsThe combination of ERK1/2 inhibition and an anti-PDL1 antibody showed enhanced efficacy in mouse syngeneic tumor models. In the EL4 model, neither ATG-017 nor atezolizumab showed single agent activity, while the combination showed significant tumor growth inhibition (TGI=22%) on day 9. No body weight loss was observed. The percentage of infiltrating CD8+ T cells, NK cells and CD8:CD4 ratio were found increased in the combination group. The mean percentage of CD8+T cells among CD45+ cells increased from 4.17% (IgG +Vehicle control), 3.81% (ATG-017), 3.23% (atezolizumab), to 12.92% in the combination group. The CD8:CD4 ratio were 0.25 (IgG+Vehicle), 0.32(ATG-017), 0.17 (atezolizumab) and 0.67 (combination), respectively (Figure 1). More data from LL/2 and A20 model are being generated.ConclusionsSynergism has been observed for the combination of checkpoint inhibition and ERK1/2 inhibition in vivo, suggesting promising therapeutic strategies for cancer patients that warrants further clinical investigation.Ethics ApprovalThe protocol and any amendment(s) or procedures involving the care and use of animals in this study were reviewed and approved by the Institutional Animal Care and Use Committee (IACUC) of CrownBio prior to execution. During the study, the care and use of animals were conducted in accordance with the regulations of the Association for Assessment and Accreditation of Laboratory Animal Care (AAALAC).All studies were conducted following an approved IACUC protocol. AUP NO.: AN-2004-09-309Abstract 608 Figure 1ATG-017-Atezolizumab combination showed in vivo synergism(A) Tumor growth curve and (B) mean body weight of EL4 syngeneic model; N=8 for each treatment group. (C) ATG-017-Atezolizumab combination increased tumor infiltrating CD8+T cells (left), CD8+/CD4+ ratio (middle), and tumor infiltrating NK cells (right). The TILs were isolated from tumor samples shown in (A). N=3 for each group.

scholarly journals Immunomodulation to enhance the efficacy of an HPV therapeutic vaccine

2020 ◽  
Vol 8 (1) ◽  
pp. e000612 ◽  
Author(s):  
Claire Smalley Rumfield ◽  
Samuel T Pellom ◽  
Y Maurice Morillon II ◽  
Jeffrey Schlom ◽  
Caroline Jochems
Keyword(s):  
T Cells ◽  
T Cell ◽  
Transforming Growth Factor ◽  
Immune Cell ◽  
Therapeutic Vaccine ◽  
Interleukin 12 ◽  
Antitumor Effects ◽  
Hpv16 E6 ◽  
Syngeneic Mouse Model

BackgroundWhile prophylactic human papillomavirus (HPV) vaccines will certainly reduce the incidence of HPV-associated cancers, these malignancies remain a major health issue. PDS0101 is a liposomal-based HPV therapeutic vaccine consisting of the immune activating cationic lipid R-DOTAP and HLA-unrestricted HPV16 peptides that has shown in vivo CD8+ T cell induction and safety in a phase I study. In this report, we have employed the PDS0101 vaccine with two immune modulators previously characterized in preclinical studies and which are currently in phase II clinical trials. Bintrafusp alfa (M7824) is a first-in-class bifunctional fusion protein composed of the extracellular domains of the transforming growth factor-β receptor type II (TGFβRII) fused to a human IgG1 monoclonal antibody blocking programmed cell death protein-1 ligand (PDL1), designed both as a checkpoint inhibitor and to bring the TGFβRII ‘trap’ to the tumor microenvironment (TME). NHS-interleukin-12 (NHS-IL12) is a tumor targeting immunocytokine designed to bring IL-12 to the TME and thus enhance the inflammatory Th1 response.MethodsWe employed TC-1 carcinoma (expressing HPV16 E6 and E7 and devoid of PDL1 expression) in a syngeneic mouse model in monotherapy and combination therapy studies to analyze antitumor effects and changes in immune cell types in the spleen and the TME.ResultsAs a monotherapy, the PDS0101 vaccine generated HPV-specific T cells and antitumor activity in mice bearing HPV-expressing mEER oropharyngeal and TC-1 lung carcinomas. When used as a monotherapy in the TC-1 model, NHS-IL12 elicited antitumor effects as well as an increase in CD8+ T cells in the TME. When used as a monotherapy, bintrafusp alfa did not elicit antitumor effects or any increase in T cells in the TME. When all three agents were used in combination, maximum antitumor effects were observed, which correlated with increases in T cells and T-cell clonality in the TME.ConclusionThese studies provide the rationale for the potential clinical use of combinations of agents that can (1) induce tumor-associated T-cell responses, (2) potentiate immune responses in the TME and (3) reduce immunosuppressive entities in the TME.

Recombinant Endoglin-Single-Chain Variable Fragment/ Induced Protein 10 Fusion Protein Potently Boosts the Anti-Tumor Efficacy of Adoptively Transferred TRP2-Specific CD8+ CD28+ Cytotoxic T Lymphocytes in Mice

2020 ◽  
Vol 16 (7) ◽  
pp. 1119-1134
Author(s):  
Yangzi Li ◽  
Xiaomei Yang ◽  
Xiaoling Lu ◽  
Zhengui Peng ◽  
Chunhui Lai ◽  
...  
Keyword(s):  
T Cells ◽  
Fusion Protein ◽  
Tumor Growth ◽  
Therapeutic Efficacy ◽  
Therapeutic Potential ◽  
Suppressor Cells ◽  
Single Chain Variable Fragment ◽  
Single Chain

In this research, we studied the therapeutic efficacy of a newly designed fusion protein containing Endoglin single-chain variable fragment and IP10 (Endoglin-scFv/IP10), together with our recently generated TRP2-specific CD8+ CD28+ CTLs (CD8+ CD28+ CTLs) in controlling melanoma growth in mice. The recombinant Endoglin-scFv/IP10 was expressed in E. coli, purified by affinity chromatography, and characterized in vitro for its chemotactic movement and immunoreactivity with endoglin-expressing cells. In vivo, melanoma xenografts were established in mice (C57BL/6) using B16F10 cells. After that, mice were treated with intravenous injections of vehicle (PBS), Endoglin-scFv/IP10 alone, CD8+ CD28+ CTLs alone, or Endoglin-scFv/IP10+ CD8+ CD28+ CTLs. The therapeutic efficacy was assessed by monitoring tumor growth, mouse survival and cellular biomarkers. Endoglin-scFv/IP10 fusion protein combined with CD8+ CD28+ CTLs observed a reduction in tumor growth, resulting in improved survival. On the cellular level, the combination treatment dramatically reduced the number of systemic and tumor associated myeloid-derived suppressor cells or regulatory T cells, increased tumor-responsive interferon-γ-producing lymphocytes and tumor-associated CD8+ CXCR3+ T cells, and inhibited proliferation and angiogenesis but stimulated apoptosis within melanoma tissue. This study demonstrates the therapeutic potential of Endoglin-scFv/IP10 fusion protein in combination with CD8+ CD28+ CTLs in melanoma treatment.

scholarly journals 893 ATG-101, a novel PD-L1/4–1BB bispecific antibody, augments anti-tumor immunity through immune checkpoint inhibition and PDL1-directed 4–1BB activation

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A936-A937
Author(s):  
Hui Yuwen ◽  
Tengteng Li ◽  
Yijing Ren ◽  
Dirk Hoenemann ◽  
Jay Mei ◽  
...  
Keyword(s):  
T Cells ◽  
Tumor Growth ◽  
Disease Progression ◽  
Mechanism Of Action ◽  
Growth Curve ◽  
Bispecific Antibody ◽  
Tumor Growth Inhibition ◽  
Animal Care

BackgroundProgrammed death-ligand 1 (PD-L1) and programmed cell death protein 1(PD-1) blockade therapy has revolutionized the treatment landscape of malignancies. However, only a minority of patients are anticipated to experience a deep and durable response. In addition, successful therapeutic agonism of 4-1BB, a promising co-stimulatory immunologic target, has been limited by major safety concerns of hepatotoxicity or suboptimal agonistic potency. ATG-101, a novel PD-L1/4-1BB bispecific antibody, was designed to activate 4-1BB positive T cells in a PDL1-crosslinking dependent manner and to effectively treat tumors without on-target-off-tumor liver toxicity (figure 1).MethodsATG-101 was developed by introducing lower affinity 4-1BB scFv into a human IgG1 PD-L1 monoclonal antibody. The N297A mutation on CH2 abolishes the binding capacity to most FcγRs but retains the binding to FcγRn. A series of in vitro and in vivo studies were performed to evaluate the potency, safety and specific mechanism of action.ResultsATG-101 simultaneous binds to 4-1BB and PD-L1 with higher affinity to PD-L1, and potently activates 4-1BB positive T cells when crosslinked by PD-L1 positive cells. Upon crosslinking, ATG-101 also activates PD1+TIM3+ exhausted T cells in vitro, suggesting a potential in reversing T-cell dysfunction and exhaustion (figure 1). ATG-101 shows potent anti-tumor activities in various animal models, including h4-1BB humanized mice bearing MC38 colon cancer, PD(L)1 blockade insensitive B16F10 melanoma and EL4 lymphoma, with no body weight loss observed. To evaluate ATG-101 efficacy in tumors progressing after anti-PD(L)1 treatment, mice bearing MC38 tumors were treated with anti-PDL1 initially to achieve tumor growth inhibition, and half of the mice switched to ATG-101 upon disease progression, the other mice continuing with anti-PD-L1 treatment. ATG-101 induced potent tumor growth inhibition and tumor regression in anti-PDL1-resistant tumors and prolonged survival. Flow cytometry and multiplex IHC staining of tumor samples from mice treated with ATG-101 or control suggest that ATG-101 increases the infiltration, proliferation and activation of CD8+ T cells (figure 2), the infiltration of natural killer T cells and the CD8+/Treg ratio in TILs. In a 4-week GLP toxicity study in cynomolgus monkey, up to 100mg/kg repeated doses of ATG-101 were well tolerated with no hepatotoxicity observed.Abstract 893 Figure 1ATG-101 conditionally activates exhausted T cells. (A) Mechanism of action of ATG-101 (B) Exhausted T cells were induced by CD3+T cells cultured with anti-CD3/CD28 beads for 6 days. The percentage of terminally exhausted T cells (PD-1+Tim-3+) and progenitor exhausted T cells (PD-1+Tim-3-) were increased on Day6 (C) With the presence of PD-L1 positive cells, ATG-101 induced the IL2 and INF-γ secretion by exhausted T cells.Abstract 893 Figure 2Potent in vivo efficacy of ATG-101. (A) Representative MC38 tumor growth curve for individual mice treated with PBS (black), 10mpk atezolizumab (Atezo) only (red) or mice initially treated with 10mpk atezolizumab and switched to 13mpk ATG-101 upon disease progression (red-green); the arrow indicates the day switching Atezo to ATG-101; (B) MC38 tumor growth curve for all individual mice treated with PBS (black, n=6), atezolizumab only (red, n=14), and atezolizumab initially before switching to ATG-101 upon disease progression (red-green, n=14) ; (C) Survival data of mouse shown in (B); (D) Representative images for multiplex IHC staining of tumor samples collected from mouse from (B). (E) Quantitative analysis of TILs shown in (D). Compared with PBS group or atezo-only group, ATG-101 significantly increased the infiltration of T cells in the tumor microenvironment. MHCII: APC Cells, CD4+ CD8-: Helper T Cells, CD4- CD8+: Cytotoxic T Cells, CD4- CD8- F4/80- PDL1+: Tumor Cells.ConclusionsATG-101 demonstrated significant anti-tumor activity in various tumor models including those progressing on anti PD(L)1 treatment. Good safety and PK/PD properties has been demonstrated in preclinical in vivo models. A phase I, multicenter, dose-escalating clinical trial evaluating ATG-101 in patients with solid tumors and hematologic malignancies is ongoing.Ethics ApprovalThe protocol and any amendment(s) or procedures involving the care and use of animals in this study were reviewed and approved by the Institutional Animal Care and Use Committee (IACUC) of CrownBio or Innostar prior to execution with an AUP number or IACUC approval number for each animal study. During the study, the care and use of animals were conducted in accordance with the regulations of the Association for Assessment and Accreditation of Laboratory Animal Care (AAALAC).All studies were conducted following an approved IACUC protocol. AUP NO.:2004-12-1465, 2004-12-1000; IACUC approval number: IACUC-2021-M-003

112 Rational design of chimeric antigen receptor T cells against glypican 3 decouples toxicity from therapeutic efficacy

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A124-A124
Author(s):  
Letizia Giardino ◽  
Ryan Gilbreth ◽  
Cui Chen ◽  
Erin Sult ◽  
Noel Monks ◽  
...  
Keyword(s):  
T Cells ◽  
Chimeric Antigen Receptor ◽  
Antigen Receptor ◽  
Single Chain ◽  
High Affinity ◽  
Car T Cells ◽  
Car T ◽  
Animal Care ◽  
Cytotoxic Function

BackgroundChimeric antigen receptor (CAR)-T therapy has yielded impressive clinical results in hematological malignancies and it is a promising approach for solid tumor treatment. However, toxicity, including on-target off-tumor antigen binding, is a concern hampering its broader use.MethodsIn selecting a lead CAR-T candidate against the oncofetal antigen glypican 3 (GPC3), we compared CAR bearing a low and high affinity single-chain variable fragment (scFv,) binding to the same epitope and cross-reactive with murine GPC3. We characterized low and high affinity CAR-T cells immunophenotype and effector function in vitro, followed by in vivo efficacy and safety studies in hepatocellular carcinoma (HCC) xenograft models.ResultsCompared to the high-affinity construct, the low-affinity CAR maintained cytotoxic function but did not show in vivo toxicity. High-affinity CAR-induced toxicity was caused by on-target off-tumor binding, based on the evidence that high-affinity but not low-affinity CAR, were toxic in non-tumor bearing mice and accumulated in organs with low expression of GPC3. To add another layer of safety, we developed a mean to target and eliminate CAR-T cells using anti-TNFα antibody therapy post-CAR-T infusion. This antibody functioned by eliminating early antigen-activated CAR-T cells, but not all CAR-T cells, allowing a margin where the toxic response could be effectively decoupled from anti-tumor efficacy.ConclusionsSelecting a domain with higher off-rate improved the quality of the CAR-T cells by maintaining cytotoxic function while reducing cytokine production and activation upon antigen engagement. By exploring additional traits of the CAR-T cells post-activation, we further identified a mechanism whereby we could use approved therapeutics and apply them as an exogenous kill switch that would eliminate early activated CAR-T following antigen engagement in vivo. By combining the reduced affinity CAR with this exogenous control mechanism, we provide evidence that we can modulate and control CAR-mediated toxicity.Ethics ApprovalAll animal experiments were conducted in a facility accredited by the Association for Assessment of Laboratory Animal Care (AALAC) under Institutional Animal Care and Use Committee (IACUC) guidelines and appropriate animal research approval.

627 The DLL3-targeted half-life extended bispecific T cell engager (HLE BiTE®) immune-oncology therapy AMG 757 has potent antitumor activity in neuroendocrine cancer

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A663-A663
Author(s):  
Keegan Cooke ◽  
Juan Estrada ◽  
Jinghui Zhan ◽  
Jonathan Werner ◽  
Fei Lee ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Growth ◽  
Mouse Models ◽  
T Cell Activation ◽  
Phase 1 ◽  
Phase 1 Study ◽  
Human T Cells

BackgroundNeuroendocrine tumors (NET), including small cell lung cancer (SCLC), have poor prognosis and limited therapeutic options. AMG 757 is an HLE BiTE® immune therapy designed to redirect T cell cytotoxicity to NET cells by binding to Delta-like ligand 3 (DLL3) expressed on the tumor cell surface and CD3 on T cells.MethodsWe evaluated activity of AMG 757 in NET cells in vitro and in mouse models of neuroendocrine cancer in vivo. In vitro, co-cultures of NET cells and human T cells were treated with AMG 757 in a concentration range and T cell activation, cytokine production, and tumor cell killing were assessed. In vivo, AMG 757 antitumor efficacy was evaluated in xenograft NET and in orthotopic models designed to mimic primary and metastatic SCLC lesions. NSG mice bearing established NET were administered human T cells and then treated once weekly with AMG 757 or control HLE BiTE molecule; tumor growth inhibition was assessed. Pharmacodynamic effects of AMG 757 in tumors were also evaluated in SCLC models following a single administration of human T cells and AMG 757 or control HLE BiTE molecule.ResultsAMG 757 induced T cell activation, cytokine production, and potent T cell redirected killing of DLL3-expressing SCLC, neuroendocrine prostate cancer, and other DLL3-expressing NET cell lines in vitro. AMG 757-mediated redirected lysis was specific for DLL3-expressing cells. In patient-derived xenograft and orthotopic models of SCLC, single-dose AMG 757 effectively engaged human T cells administered systemically, leading to a significant increase in the number of human CD4+ and CD8+ T cells in primary and metastatic tumor lesions. Weekly administration of AMG 757 induced significant tumor growth inhibition of SCLC (figure 1) and other NET, including complete regression of established tumors and clearance of metastatic lesions. These findings warranted evaluation of AMG 757 (NCT03319940); the phase 1 study includes dose exploration (monotherapy and in combination with pembrolizumab) and dose expansion (monotherapy) in patients with SCLC (figure 2). A study of AMG 757 in patients with neuroendocrine prostate cancer is under development based on emerging data from the ongoing phase 1 study.Abstract 627 Figure 1AMG 757 Significantly reduced tumor growth in orthotopic SCLC mouse modelsAbstract 627 Figure 2AMG 757 Phase 1 study designConclusionsAMG 757 engages and activates T cells to kill DLL3-expressing SCLC and other NET cells in vitro and induces significant antitumor activity against established xenograft tumors in mouse models. These preclinical data support evaluation of AMG 757 in clinical studies of patients with NET.Ethics ApprovalAll in vivo work was conducted under IACUC-approved protocol #2009-00046.

823 CD4 T cells are essential for an anti-tumor effect in a B78 murine melanoma tumor model

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A873-A873
Author(s):  
Arika Feils ◽  
Mackenzie Heck ◽  
Anna Hoefges ◽  
Peter Carlson ◽  
Luke Zangl ◽  
...  
Keyword(s):  
T Cells ◽  
Tumor Growth ◽  
Cd4 T Cells ◽  
Tumor Response ◽  
Immune Cell ◽  
Cd8 T Cell ◽  
Mhc I ◽  
Mhc Ii ◽  
Flow Cytometric

BackgroundMice bearing B78 melanoma tumors can be cured using an in situ vaccine (ISV) regimen that includes radiation (RT) together with immunocytokine (tumor-targeting mAb conjugated to IL-2). B78 melanoma cells, derived from B16 cells, express minimal to no MHC-I but express MHC-II upon IFN-g/TNF-a stimulation. Although B78 cells are primarily MHC-I-deficient, an increased CD8 T cell infiltration into the tumor microenvironment (TME) has been shown following ISV.1 To further investigate the potential role of specific immune cell lineages in the B78 anti-tumor response to ISV, immune subset depletion studies and flow cytometric analyses were performed.MethodsC57BL/6 mice bearing B78 tumors were depleted of immune cell subsets with mAbs (anti-CD4, anti-CD8, anti-NK1.1, or Rat IgG control) for 3 weeks during the course of treatment. Treatment groups included no treatment, RT (12 Gy), or ISV (RT D0 and immunocytokine D5-D9). 6 mice/group (repeated three times) were followed for survival/tumor growth, and flow cytometry studies included 4 mice/group, sacrificed on D8 and D13 following the start of ISV.ResultsMice depleted of CD4 T cells during the course of ISV showed a significant reduction of anti-tumor effect as compared to mice treated with ISV/Rat IgG (pConclusionsThese studies suggest that CD4 T cells are essential for an anti-tumor response in the B78 melanoma model. In vivo depletion data show that CD4 T cells, but not CD8 or NK cells, are required for a decrease in tumor growth via ISV. Flow cytometric analyses suggest an interplay between CD4 and CD8 T cells as indicated by a decrease in CD8/IFN-g expression following ISV in the absence of CD4 T cells. The role that MHC-I and MHC-II expression plays in this CD4/CD8 T cell anti-tumor response is under investigation. In future studies, B78 melanoma may serve as a critical syngeneic model for development of more effective immunotherapy treatment regimens.Ethics ApprovalAll animal experiments were performed in accordance with protocols approved by Animal Care and Use Committees of the University of Wisconsin-Madison.ReferenceMorris Z, Guy E, Francis D, et al. In situ tumor vaccination by combining local radiation and tumor-specific antibody or immunocytokine treatments. Cancer Res 2016;76(13):3929-3941.

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