scholarly journals Conversion of Anergic T Cells Into Foxp3- IL-10+ Regulatory T Cells by a Second Antigen Stimulus In Vivo

2021 ◽  
Vol 12 ◽  
Author(s):  
Anna Sophie Thomann ◽  
Theresa Schneider ◽  
Laura Cyran ◽  
Ina Nathalie Eckert ◽  
Andreas Kerstan ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Time Window ◽  
Common Mechanism ◽  
Short Term ◽  
Subsequent Conversion ◽  
Time Periods ◽  
Anergic T Cells ◽  
Tr1 Cells

T cell anergy is a common mechanism of T cell tolerance. However, although anergic T cells are retained for longer time periods in their hosts, they remain functionally passive. Here, we describe the induction of anergic CD4+ T cells in vivo by intravenous application of high doses of antigen and their subsequent conversion into suppressive Foxp3- IL-10+ Tr1 cells but not Foxp3+ Tregs. We describe the kinetics of up-regulation of several memory-, anergy- and suppression-related markers such as CD44, CD73, FR4, CD25, CD28, PD-1, Egr-2, Foxp3 and CTLA-4 in this process. The conversion into suppressive Tr1 cells correlates with the transient intracellular CTLA-4 expression and required the restimulation of anergic cells in a short-term time window. Restimulation after longer time periods, when CTLA-4 is down-regulated again retains the anergic state but does not lead to the induction of suppressor function. Our data require further functional investigations but at this stage may suggest a role for anergic T cells as a circulating pool of passive cells that may be re-activated into Tr1 cells upon short-term restimulation with high and systemic doses of antigen. It is tentative to speculate that such a scenario may represent cases of allergen responses in non-allergic individuals.

Opposing Effects of PD-1/PD-L1/L2 Engagement and IFN-γ/TNF-α in the Treatment of AML w/ Anti-CD33 Chimeric Antigen Receptor-Modified T Cells

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 5891-5891
Author(s):  
Jacob Halum Basham ◽  
Terrence L. Geiger
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
Chimeric Antigen Receptor ◽  
Short Term ◽  
Car T Cells ◽  
Tnf Α ◽  
Car T ◽  
Ifn Γ

Abstract Chimeric antigen receptor-modified T lymphocytes (CART cells) have shown benefit as an adjuvant immunotherapy in the treatment of B cell malignancies. This success of re-targeted T cells has not been extended to other hematologic malignancies. We have developed an immunotherapeutic approach to treat acute myeloid leukemia (AML) using CAR T cells re-directed against the myeloid-specific antigen CD33 (CART-33). CART-33 cells are potent and specific in eliminating AML cells in vitro and in vivo. Despite this, CART-33 cells have shown poor in vivo expansion and persistence in NOD-SCID IL2rγ (-/-) (NSG) AML xenograft models. To address the reason for this, we assessed the impact of AML-expressed programmed death ligands 1 & 2 (PD-L1/2) on CART-33 cell activity. PD-L1 inhibits T cell functions upon binding PD-1, which is upregulated with T cell activation. Less is known about PD-L2's effect. Interferon-gamma (IFN-γ), a primary effector cytokine secreted by CD4+ and CD8+ effector T cells, is a known potent inducer of PD-L1 on AML blasts. Using AML cell lines U937, Oci-AML3, CMK, and MV4-11 we show that IFN-γ, TNF-α, and activated CART-33 supernatant can induce up-regulation of PD-L1 and PD-L2 on AML. IFN-γ and TNF-α synergize strongly in up-regulating PD-1 ligands on AML. The kinetics and induction of PD-L2 are distinct from that of PD-L1. Although PD-L1 is well documented to suppress T cell function via ligation of T cell expressed PD-1, induction of PD-L1/L2 had no effect on the cytolytic activity of CART-33 cells against AML in short term (<48 h) cultures. Paradoxically, 24 hr pre-treatment of AML with either IFN-γ or CART-33 supernatant increased AML susceptibility to killing by CART-33 cells despite elevated expression of PD-L1/L2 by AML. Our results highlight the regulatory complexity of AML cytolysis by re-targeted T lymphocytes, and argue that tumor-expressed PD-L1 and PD-L2 impacts the sustainability, but not short-term killing activity, of adoptively transferred CAR T cells in the treatment of AML. Disclosures No relevant conflicts of interest to declare.

scholarly journals Preclinical Rationale for Targeting the PD-1/PD-L1 Axis in Combination with a CD38 Antibody in Multiple Myeloma and Other CD38-Positive Malignancies

Cancers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3713
Author(s):  
Christie P. M. Verkleij ◽  
Amy Jhatakia ◽  
Marloes E. C. Broekmans ◽  
Kristine A. Frerichs ◽  
Sonja Zweegman ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
Ex Vivo ◽  
Suppressor Cells ◽  
Newly Diagnosed ◽  
Short Term ◽  
Expression Levels ◽  
Cell Immunity

The CD38-targeting antibody daratumumab mediates its anti-myeloma activities not only through Fc-receptor-dependent effector mechanisms, but also by its effects on T-cell immunity through depletion of CD38+ regulatory T-cells, regulatory B-cells, and myeloid-derived suppressor cells. Therefore, combining daratumumab with modulators of other potent immune inhibitory pathways, such as the PD-1/PD-L1 axis, may further improve its efficacy. We show that multiple myeloma (MM) cells from relapsed/refractory patients have increased expression of PD-L1, compared to newly diagnosed patients. Furthermore, PD-1 is upregulated on T-cells from both newly diagnosed and relapsed/refractory MM patients, compared to healthy controls. In short-term experiments with bone marrow samples from MM patients, daratumumab-mediated lysis was mainly associated with the MM cells’ CD38 expression levels and the effector (NK-cells/monocytes/T-cells)-to-target ratio, but not with the PD-L1 expression levels or PD-1+ T-cell frequencies. Although PD-1 blockade with nivolumab did not affect MM cell viability or enhanced daratumumab-mediated lysis in short-term ex vivo experiments, nivolumab resulted in a mild but clear increase in T-cell numbers. Moreover, with a longer treatment duration, PD-1 blockade markedly improved anti-CD38 antibody-mediated cytotoxicity in vivo in murine CD38+ tumor models. In conclusion, dual targeting of CD38 and PD-1 may represent a promising strategy for treating MM and other CD38-positive malignancies.

scholarly journals Activating Fc γ receptors contribute to the antitumor activities of immunoregulatory receptor-targeting antibodies

2013 ◽  
Vol 210 (9) ◽  
pp. 1685-1693 ◽  
Author(s):  
Yannick Bulliard ◽  
Rose Jolicoeur ◽  
Maurice Windman ◽  
Sarah M. Rue ◽  
Seth Ettenberg ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Receptor Activation ◽  
Antibody Engineering ◽  
Negative Regulator ◽  
Common Mechanism ◽  
Target Cells ◽  
Antitumor Effects ◽  
Cell Immunity

Fc γ receptor (FcγR) coengagement can facilitate antibody-mediated receptor activation in target cells. In particular, agonistic antibodies that target tumor necrosis factor receptor (TNFR) family members have shown dependence on expression of the inhibitory FcγR, FcγRIIB. It remains unclear if engagement of FcγRIIB also extends to the activities of antibodies targeting immunoregulatory TNFRs expressed by T cells. We have explored the requirement for activating and inhibitory FcγRs for the antitumor effects of antibodies targeting the TNFR glucocorticoid-induced TNFR-related protein (GITR; TNFRSF18; CD357) expressed on activated and regulatory T cells (T reg cells). We found that although FcγRIIB was dispensable for the in vivo efficacy of anti-GITR antibodies, in contrast, activating FcγRs were essential. Surprisingly, the dependence on activating FcγRs extended to an antibody targeting the non-TNFR receptor CTLA-4 (CD152) that acts as a negative regulator of T cell immunity. We define a common mechanism that correlated with tumor efficacy, whereby antibodies that coengaged activating FcγRs expressed by tumor-associated leukocytes facilitated the selective elimination of intratumoral T cell populations, particularly T reg cells. These findings may have broad implications for antibody engineering efforts aimed at enhancing the therapeutic activity of immunomodulatory antibodies.

scholarly journals Beyond type 1 regulatory T cells: co-expression of LAG3 and CD49b in IL-10-producing T cell lineages

2018 ◽  
Author(s):  
Weishan Huang ◽  
Sabrina Solouki ◽  
Chavez Carter ◽  
Song-Guo Zheng ◽  
Avery August
Keyword(s):  
T Cells ◽  
T Cell ◽  
Treg Cells ◽  
Cell Lineages ◽  
Transgenic Murine Model ◽  
Differentiation Stage ◽  
Tr1 Cells

ABSTRACTType 1 regulatory CD4+T (Tr1) cells express high levels of the immunosuppressive cytokine IL-10 but not the master transcription factor Foxp3, and can suppress inflammation and promote immune tolerance. In order to identify and obtain viable Tr1 cells for research and clinical applications, co-expression of CD49b and LAG3 has been proposed as a unique surface signature for both human and mouse Tr1 cells. However, recent studies have revealed that this pattern of co-expression is dependent on the stimulating conditions and the differentiation stage of the CD4+T cells. Here, using an IL-10GFP/Foxp3RFPdual reporter transgenic murine model, we demonstrate that co-expression of CD49b and LAG3 is not restricted to the Foxp3−Tr1 cells, but is also observed in Foxp3+T regulatory (Treg) cells and CD8+T cells that produce IL-10. Our data indicate that IL-10-producing Tr1 cells, Treg cells and CD8+T cells are all capable of co-expressing LAG3 and CD49bin vitrofollowing differentiation under IL-10-inducing conditions, andin vivofollowing pathogenic insult or infection in the pulmonary mucosa. Our findings urge caution in the use of LAG3/CD49b co-expression to identify Tr1 cells, since it may mark IL-10-producing T cell lineages more broadly, including the Foxp3−Tr1 cells, Foxp3+Treg cells and CD8+T cells.

Oncoretroviral and Lentiviral Transduction of Donor T Cells to Facilitate Engraftment of Dog Leukocyte Antigen (DLA)-Haploidentical T-Cell-Depleted Marrow.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1751-1751
Author(s):  
Dario Sangiolo ◽  
Marina Lesnikova ◽  
Alla Nikitine ◽  
Hans-Peter Kiem ◽  
Rainer Storb ◽  
...  
Keyword(s):  
Cell Culture ◽  
T Cells ◽  
T Cell ◽  
Transduction Efficiency ◽  
Endogenous Virus ◽  
Short Term ◽  
Donor T Cells ◽  
Allogeneic Stimulation ◽  
Short Term Culture

Abstract Several clinical studies of adoptive immunotherapy with genetically modified (GM) donor T cells infused after allogeneic hematopoietic cell transplantation (HCT) showed limited in vivo function of the transduced T cells. Factors that have hindered successful translation to clinical trials include insufficient preclinical data in large animal models and the need for prolonged cell culture - up to 2 to 3 weeks for optimal oncoretroviral (OR) vector transduction and selection of T cells. In preparation for in vivo studies of GM T cells to facilitate engraftment in the preclinical dog model of allogeneic HCT, we compared transduction protocols with OR and lentiviral (LV) vectors that aimed to decrease the duration of ex vivo T cell culture necessary for stable transduction while maintaining T cell alloreactivity. Vectors expressed enhanced yellow fluorescent protein (YFP) under a constitutive promoter. We compared vectors pseudotyped with viral glycoproteins (GP) including vesicular stomatitis virus (VSV)-G (LV only), feline endogenous virus (RD114), and chimeric RD114 envelope GP fused with murine leukemia virus-A cytoplasmic tail (RD114/TR). Although T cells transduced with LV vectors without prior mitogenic or allogeneic stimulation had 14% – 30% transduction efficiency of predominantly CD4+ cells, transgene expression was not sustained in CD8+ cells after allogeneic stimulation (n=3). In order to transduce T cells that could generate GM alloreactive cytotoxic T lymphocytes (CTL), freshly isolated T cells were stimulated with allogeneic dendritic cells (DC) for 4 days prior to transduction. VSV-G, RD114 or RD114/TR pseudotyped LV had primary transduction efficiency of 1.2 to 9% (n=5). Only cells that were transduced with RD114 or RD114/TR pseudotyped vectors maintained stable YFP expression after 2° allogeneic stimulation. Next, OR YFP vector pseudotyped with RD114 transduced 15 to 36% of DC allo-stimulated T cells (n=3). Both CD4+ and CD8+ cell populations were transduced (CD4+: CD8+ ratio 1.4:1) and the mean YFP fluorescence intensity was increased 0.6-log compared to LV vectors (p=0.01). We then evaluated T cells transduced with OR RD114 pseudotyped vector in vivo. To determine if short-term culture and transduction of T cells facilitated engraftment of CD3-depleted marrow in the DLA-haploidentical HCT model, donor T cells were collected on day −7 prior to HCT, cultured with recipient CD34+ derived DC, and on day −4 cells were transduced with RD114 pseudotyped YFP OR vector. To date, one dog was transplanted after 920cGy total body irradiation with 2x108 CD3+ donor cells/kg (1:1 CD4:CD8 ratio) 25% YFP expression and 2-log CD3-depleted marrow (4x108 TNC/kg). No post-grafting immunosuppression was given. Donor YFP transduced T cells were detected in the peripheral blood daily after HCT, and peaked on day +7. After engraftment on day +8, GVHD developed and the dog was euthanized on day +21 with all-donor chimerism. YFP+ T cells were detected in GVHD affected target organs. Previously, transduced donor CTL cultured for 4 weeks and transplanted with CD3-depleted marrow in this HCT model failed to engraft in all 5 dogs studied. These preliminary results support the hypothesis that short-term culture and transduction of donor T cells with RD114 pseudotyped OR vector maintain in vivo alloreactivity and facilitate engraftment of CD3-depleted marrow in MHC-mismatched recipients.

scholarly journals T–cell anergy and peripheral T–cell tolerance

2001 ◽  
Vol 356 (1409) ◽  
pp. 625-637 ◽  
Author(s):  
Robert Lechler ◽  
Jian-Guo Chai ◽  
Federica Marelli-Berg ◽  
Giovanna Lombardi
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Contact ◽  
T Cell Tolerance ◽  
Cell Tolerance ◽  
T Cell Anergy ◽  
Cell Anergy ◽  
Anergic T Cells

The discovery that T–cell recognition of antigen can have distinct outcomes has advanced understanding of peripheral T–cell tolerance, and opened up new possibilities in immunotherapy. Anergy is one such outcome, and results from partial T–cell activation. This can arise either due to subtle alteration of the antigen, leading to a lower–affinity cognate interaction, or due to a lack of adequate co–stimulation. The signalling defects in anergic T cells are partially defined, and suggest that T–cell receptor (TCR) proximal, as well as downstream defects negatively regulate the anergic T cell's ability to be activated. Most importantly, the use of TCR–transgenic mice has provided compelling evidence that anergy is an in vivo phenomenon, and not merely an in vitro artefact. These findings raise the question as to whether anergic T cells have any biological function. Studies in rodents and in man suggest that anergic T cells acquire regulatory properties; the regulatory effects of anergic T cells require cell to cell contact, and appear to be mediated by inhibition of antigen–presenting cell immunogenicity. Close similarities exist between anergic T cells, and the recently defined CD4 + CD25 + population of spontaneously arising regulatory cells that serve to inhibit autoimmunity in mice. Taken together, these findings suggest that a spectrum of regulatory T cells exists. At one end of the spectrum are cells, such as anergic and CD4 + CD25 + T cells, which regulate via cell–to–cell contact. At the other end of the spectrum are cells which secrete antiinflammatory cytokines such as interleukin 10 and transforming growth factor–β. The challenge is to devise strategies that reliably induce T–cell anergy in vivo , as a means of inhibiting immunity to allo– and autoantigens.

scholarly journals Activin-A co-opts IRF4 and AhR signaling to induce human regulatory T cells that restrain asthmatic responses

2017 ◽  
Vol 114 (14) ◽  
pp. E2891-E2900 ◽  
Author(s):  
Sofia Tousa ◽  
Maria Semitekolou ◽  
Ioannis Morianos ◽  
Aggelos Banos ◽  
Aikaterini I. Trochoutsou ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Aryl Hydrocarbon Receptor ◽  
Allergic Diseases ◽  
Activin A ◽  
Humanized Mouse Model ◽  
Aryl Hydrocarbon ◽  
Human T Cell ◽  
Tr1 Cells

Type 1 regulatory T (Tr1) cells play a pivotal role in restraining human T-cell responses toward environmental allergens and protecting against allergic diseases. Still, the precise molecular cues that underlie their transcriptional and functional specification remain elusive. Here, we show that the cytokine activin-A instructs the generation of CD4+ T cells that express the Tr1-cell–associated molecules IL-10, inducible T-Cell costimulator (ICOS), lymphocyte activation gene 3 protein (LAG-3), and CD49b, and exert strongly suppressive functions toward allergic responses induced by naive and in vivo-primed human T helper 2 cells. Moreover, mechanistic studies reveal that activin-A signaling induces the activation of the transcription factor interferon regulatory factor (IRF4), which, along with the environmental sensor aryl hydrocarbon receptor, forms a multipartite transcriptional complex that binds in IL-10 and ICOS promoter elements and controls gene expression in human CD4+ T cells. In fact, IRF4 silencing abrogates activin-A–driven IL10 and ICOS up-regulation and impairs the suppressive functions of human activin-A–induced Tr1-like (act-A–iTr1) cells. Importantly, using a humanized mouse model of allergic asthma, we demonstrate that adoptive transfer of human act-A–iTr1 cells, both in preventive and therapeutic protocols, confers significant protection against cardinal asthma manifestations, including pulmonary inflammation. Overall, our findings uncover an activin-A–induced IRF4-aryl hydrocarbon receptor (AhR)–dependent transcriptional network, which generates suppressive human Tr1 cells that may be harnessed for the control of allergic diseases.

T-Cell-Mediated Suppression: From Bench to Bedside

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. SCI-37-SCI-37
Author(s):  
Maria Grazia Roncarolo ◽  
Manuela Battaglia ◽  
Rosa Bacchetta ◽  
Megan Levings ◽  
Silvia Gregori
Keyword(s):  
T Cells ◽  
T Cell ◽  
Peripheral Blood ◽  
Cd4 T Cells ◽  
Allogeneic Hsct ◽  
Cell Responses ◽  
Pathological Conditions ◽  
Tr1 Cells

Abstract T regulatory cells (Tregs) play a pivotal role in promoting and maintaining tolerance. Several subsets of Tregs have been identified but, to date, the best characterized are the CD4+FOXP3+ Tregs (FOXP3+Tregs), thymic-derived or induced in the periphery, and the CD4+ IL-10-producing T regulatory type 1 (Tr1) cells. In the past decade much effort has been dedicated to develop methods for the in vitro induction and expansion of FOXP3+Tregs and of Tr1 cells for Treg-based cell therapy to promote and restore tolerance in T-cell mediated diseases, and for expanding antigen (Ag)-specific Tregs in vivo. FOXP3+Tregs constitutively express high levels of CD25 and of the transcription factor FOXP3. FOXP3+Tregs are distinguished from activated CD4+ T cells by the low expression of CD127, and by the DNA demethylation of a specific region of the FOXP3 gene called Treg-specific demethylated region (TSDR). FOXP3+Tregs suppress effector T-cell responses through cell-to-cell contact-dependent mechanisms and suppression requires activation via TCR and is IL-2 dependent. In vitro protocols to expand FOXP3+Tregs for adoptive transfer in vivo have been established. We demonstrated that rapamycin permits the in vitro expansion of FOXP3+Tregs while impairing the proliferation of non-Tregs. Moreover, rapamycin-expanded FOXP3+Tregs maintain their regulatory phenotype in a proinflammatory environment and Th17 cells do not expand in the presence of rapamycin. Despite the progress in FOXP3+Tregs expansion protocols, adoptive transfer of FOXP3+Tregs in humans remains a difficult experimental procedure due to the ability to expand a sufficient number of Ag-specific FOXP3+Tregs in vitro. To propagate a homogenous population of FOXP3+Tregs we developed a lentiviral vector (LV)-based strategy to ectopically express FOXP3 in CD4+ T cells. This method results in the development of suppressive cells that are super-imposable to FOXP3+Tregs. Conversion of effector T cells into FOXP3+Tregs upon LV-mediated gene transfer of wild-type FOXP3 was also obtained in CD4+T cells from immunodysregulation polyendocrinopathy enteropathy X-linked (IPEX) patients. We also developed a LV platform, which selectively targets expression of the transgene in hepatocytes, to induce tolerance to self or exogenous Ags. Using this approach we showed that systemic administration of LV encoding for the gene of interest leads to the induction of Ag-specific FOXP3+ Tregs, which mediate tolerance even in pre-immunized hosts. Tr1 cells are identified by their cytokine profile (IL-10+TGF-b+IL-4-IL-17-). Tr1 cells express transiently FOXP3 upon activation; but FOXP3 expression never reaches the high levels characteristic of FOXP3+Tregs. Tr1 cell differentiation and function is independent of FOXP3 since suppressive Tr1 cells can be isolated or generated from peripheral blood of IPEX patients. Tr1 cells were first discovered in peripheral blood of patients who developed tolerance after HLA-mismatched fetal liver hematopoietic stem cell transplant (HSCT). Since their discovery, Tr1 cells have proven to be important in mediating tolerance in several immune-mediated diseases. The immuno-regulatory mechanisms of Tr1 cells have been studied over the years thanks to the possibility to generate these cells in vitro. Tr1 cells suppress T-cell responses via the secretion of IL-10 and TGF-β and by the specific killing of myeloid APC via Granzyme B and perforin. Tr1 cells can be induced in vitro in an Ag-specific manner in the presence of IL-10 or of DC-10. Proof-of-principle clinical trials in allogeneic HSCT demonstrated the safety of Treg-based cell therapy with these polarized Tr1 cells. We are currently planning a phase I/II trial using in vitro polarized Tr1 cells with DC-10 in patients after kidney transplantation. An alternative strategy for the induction of high numbers of human Tr1 cells is the LV-mediated gene transfer of human IL-10 into conventional CD4+ T cells. Stable ectopic expression of IL-10 leads to the differentiation of homogeneous populations of Tr1-like cells displaying potent suppressive functions both in vitro and in vivo. A major hurdle, which limited the studies and the clinical use of Tr1 cells, was the lack of specific biomarkers. By gene expression profiling of human Tr1 cell clones we identified two surface markers (CD49b and LAG-3), which are stably and selectively co-expressed on murine and human Tr1 cells induced in vitro or in vivo. The co-expression of CD49b and LAG-3 enables the isolation of highly suppressive Tr1 cells from in vitro IL-10-polarized Tr1 cells and allows tracking of Tr1 cells in peripheral blood of patients who developed tolerance after allogeneic HSCT. The identification of CD49b and LAG-3 as Tr1-specific biomarkers will facilitate the study of Tr1 cells in vivo in healthy and pathological conditions and the use of Tr1 cells for forthcoming therapeutic interventions. In conclusion, Tregs play a key role in maintaining immunological homeostasis in the periphery. Several open questions regarding FOXP3+ Tregs or Tr1 cell-based therapy in humans remain: how long do Tregs survive after transfer? Is their phenotype stable in pathological conditions and inflammatory environments? Is their mechanism of suppression in vivo Ag-specific? Carefully designed and standardized future clinical protocols reflecting a concerted action among different investigators will help to address these questions and to advance the field. Disclosures: No relevant conflicts of interest to declare.

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.

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