Leveraging a physiologically based quantitative translational modeling platform for designing bispecific T cell engagers for treatment of multiple myeloma

Bispecific T cell engager (TCE) is an emerging anti-cancer modality which redirects cytotoxic T cells to tumor cells expressing tumor-associated antigen (TAA) thereby forming immune synapses to exerts anti-tumor effects. Considering the protein engineering challenges in designing and optimizing size and pharmacokinetically acceptable TCEs in the context of the complexity of intercellular bridging between T cells and tumor cells, a physiologically relevant and clinically verified computational modeling framework is of crucial importance to guide the process to understand the protein engineering trade offs. In this study, we developed a quantitative, physiologically based computational framework to predict immune synapse formation for a variety of molecular format of TCEs in tumor tissue. Our model incorporated the molecular size dependent biodistribution using the two pore theory, extra-vascularization of T cells and hematologic cancer cells, mechanistic bispecific intercellular binding of TCEs and competitive inhibitory interaction by shed targets. The biodistribution of TCE was verified by positron emission tomography imaging of [89Zr]AMG211 (a carcinoembryonic antigen-targeting TCE) in patients. Parameter sensitivity analyses indicated that immune synapse formation was highly sensitive to TAA expression, degree of target shedding and binding selectivity to tumor cell surface TAA over shed target. Interestingly, the model suggested a “sweet spot” for TCE’s CD3 binding affinity which balanced the trapping of TCE in T cell rich organs. The final model simulations indicated that the number of immune synapses is similar (~50/tumor cell) between two distinct clinical stage B cell maturation antigen (BCMA)-targeting TCEs, PF-06863135 in IgG format and AMG420 in BiTE format, at their respective efficacious dose in multiple myeloma patients, demonstrating the applicability of the developed computational modeling framework to molecular design optimization and clinical benchmarking for TCEs. This framework can be employed to other targets to provide a quantitative means to facilitate the model-informed best in class TCE discovery and development.

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Functional Screening Studies Identify Combinational Activity of PD-L1 and CD200 In Mediating Dysfunctional T Cell Immunological Synapse Formation In Chronic Lymphocytic Leukemia

Blood ◽

10.1182/blood.v116.21.696.696 ◽

2010 ◽

Vol 116 (21) ◽

pp. 696-696

Author(s):

Alan G. Ramsay ◽

Andrew James Clear ◽

Alexander Davenport ◽

Rewas Fatah ◽

John G. Gribben

Keyword(s):

T Cells ◽

T Cell ◽

Tumor Cells ◽

Immune Suppression ◽

Neutralizing Antibodies ◽

Synapse Formation ◽

Ex Vivo ◽

Lymphocytic Leukemia ◽

Immune Synapse ◽

Cell Synapse

Abstract Abstract 696 The ability of cancer cells to modulate the immune microenvironment is now recognized as an important hallmark of disease pathophysiology. Identifying the molecular mechanisms of cancer immune suppression in the laboratory is key to the design of more effective immunotherapeutic treatment strategies. We previously demonstrated that chronic lymphocytic leukemia (CLL) cells induce alterations in global gene expression profiles in patient CD4 and CD8 T cells, and a profound T cell immunological synapse formation defect that can be reversed with lenalidomide (J Clin Invest. 2005;115(7):1797-1805, and 2008;118(7):2427-2437). Here we used small interfering RNA (siRNA) with a 2-part functional screen to identify key CLL cell molecules inducing T cell immune suppression. siRNA treated tumor cells were cocultured in direct contact with healthy allogeneic T cells for 24 hours, T cells purified from coculture and used in cell conjugation immune synapse assays with superantigen-pulsed third party B cells as antigen-presenting cells (APCs). Confocal microscopy and image analysis software was used to quantify the mean area of T cell F-actin immune synapse formation events from each experimental cell population. Treatment of the CLL cell line MEC-1 with either TNFα, TGFβ, IL-10, or IL-6 siRNA identified no gain in subsequent CD3 T cell immune synapse function compared to control non-targeting siRNA or untreated CLL cells. However, CD200 or programmed death 1 (PD1) ligand 1 (PD-L1, CD274) siRNA treatment significantly enhanced (P < .01) subsequent T cell synapse formation events with APCs (comparable to positive control experiments blocking tumor cell:T cell direct contact with ICAM-1 siRNA, or primary coculture of T cells with allogeneic healthy donor B cells). Primary CLL patient cells (n=10) were treated with individual or pooled neutralizing antibodies, or siRNA, targeting PD-L1, CD200, or cytokines. This analysis revealed that counteracting the combined activity of PD-L1, CD200 and TGFβ exhibited the most pronounced repair of subsequent T cell synapse function compared to control treated tumor cells (P < .01). These data suggest that CLL-released cytokines such as TGFβ contribute to, but are not essential for the T cell synapse defect. We also identified that blocking the T cell receptors PD-1, CD200-R and TGFβ-R1 with neutralizing antibodies prevents CLL inhibitory signaling (P < .01) compared to isotype control IgG treated T cells in contact with tumor cells. We further show that knock-down of PD-L1, CD200 and TGFβ on ex vivo CLL cells prevents inhibitory CD4 and CD8 T cell synapse function compared to control siRNA (P < .01) using the Eμ-TCL1 mouse model of CLL. The addition of lenalidomide (1μM) in ex vivo CLL cell:T cell coculture assays significantly increased (P < .01) subsequent T cell synapse function compared to untreated vehicle control experiments. Flow cytometric analysis identified that lenalidomide down-regulates both CLL expressed PD-L1 and CD200 ligands, and T cell cognate receptor PD1 and CD200R expression during intercellular contact interactions. Moreover, subsequent effector T cell killing function was significantly enhanced (P < .05) following antibody blockade of CLL cell PD-L1 and CD200 with or without lenalidomide treatment during primary coculture with CD8 T cells. We are currently investigating the expression and activity of PD-L1, CD200, and other co-inhibitory molecules in CLL and other haematological and solid malignancies, using patient tissue microarray analysis and confocal co-localization analysis. This work is identifying common inhibitory ligands utilized by tumor cells to suppress T cell synapse function. These results provide important mechanistic insight into immune suppression in CLL and the action of lenalidomide, and identify co-inhibitory ligands as potential immunotherapeutic targets to repair T cell function. Disclosures: Gribben: Roche: Consultancy; Celgene: Consultancy; GSK: Honoraria; Napp: Honoraria.

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ISB 1342: A first-in-class CD38 T cell engager for the treatment of relapsed refractory multiple myeloma.

Journal of Clinical Oncology ◽

10.1200/jco.2021.39.15_suppl.8044 ◽

2021 ◽

Vol 39 (15_suppl) ◽

pp. 8044-8044

Author(s):

Marie-Agnès Doucey ◽

Blandine Pouleau ◽

Carole Estoppey ◽

Cian Stutz ◽

Amelie Croset ◽

...

Keyword(s):

Multiple Myeloma ◽

T Cells ◽

T Cell ◽

Tumor Cell ◽

Tumor Cells ◽

Cell Killing ◽

Fragment Antigen Binding ◽

Tumor Cell Killing

8044 Background: ISB 1342 is a bispecific antibody heterodimer based on the Ichnos proprietary Bispecific Engagement by Antibodies based on T cell receptor (BEAT) platform. ISB 1342 is a first-in-class CD38 T cell engager under investigation in subjects with relapsed multiple myeloma refractory to proteasome inhibitors (PIs), immunomodulators (IMiDs) and daratumumab (study ISB 1342-101). Methods: ISB 1342 was engineered with a single chain variable fragment (scFv) arm that specifically recognizes a cluster of differentiation (CD)3-epsilon (CD3ε) and a fragment antigen binding (Fab) arm which specifically recognizes CD38 and does not compete with daratumumab. By co-engaging CD3ε on T cells and CD38 on tumor cells, ISB 1342 redirects T cells to kill CD38-expressing tumor cells. This mechanism of action is differentiated from existing monospecific CD38 targeting therapies and was designed to overcome resistance to daratumumab in multiple myeloma. Results: In vitro, ISB 1342 killed a large range of CD38-expressing tumor cell lines (EC50:12 to 90 pM) with 8 to 239-fold superior efficacy than daratumumab. ISB 1342 was also able to efficiently kill CD38 low-intermediate-expressing tumor cells that were poorly killed by daratumumab. ISB 1342 retained the potency to kill CD38 low-intermediate-expressing tumor cells when used in sequential or concomitant combination with daratumumab. In addition, the presence of soluble CD38 or glucocorticoid did not impact ISB 1342 killing potency. ISB 1342 was constructed with a double LALA mutation that dampens the binding to Fcγ receptors and C1q. Consistently, ISB 1342 showed only residual Fc-mediated effector functions and its mechanism of tumor cell killing critically relies on the engagement and the activation of T lymphocytes. ISB 1342 showed a favorable on target specificity profile in vitro and was unable to activate T cells in the absence of CD38 positive target cells. Further, ISB 1342-induced tumor cell killing was not associated with a detectable T cell fratricide in vitro. Finally, the potency of ISB 1342 was assessed in vivo in a therapeutic model of a subcutaneously established Daudi tumor co-xenografted with human PBMCs. In marked contrast to daratumumab, which induced only a partial tumor control, ISB 1342 induced complete tumor eradication when injected intravenously weekly at 0.5 mg/kg. As anticipated, the ISB 1342 control molecule (ISB 1342_13DU) made of an irrelevant CD38 binder failed to control tumor growth. The release of the Granzyme A and B, TNF-alpha and CXCL-10 in the tumor micro-environment one week post-treatment was strongly and significantly increased by ISB 1342 but not by daratumumab and ISB 1342_13DU; this represents a correlate of anti-tumor immunity associated with ISB 1342 efficacy in vivo. Conclusions: Hence the higher potency of ISB 1342 relative to daratumumab supports the ongoing clinical development in multiple myeloma patients.

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Bigger, Stronger, Faster: Chimeric Antigen Receptor T Cells Are Olympic Killers

Blood ◽

10.1182/blood.v128.22.814.814 ◽

2016 ◽

Vol 128 (22) ◽

pp. 814-814 ◽

Cited By ~ 1

Author(s):

Paul J Neeson ◽

Alexander James Davenport ◽

Joseph A Trapani ◽

Michael Kershaw ◽

Ryan Cross ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Tumor Cell ◽

Tumor Cells ◽

Chimeric Antigen Receptor ◽

Antigen Receptor ◽

Time Lapse ◽

Immune Synapse ◽

Car T Cells ◽

Car T

Abstract Chimeric antigen receptor T cells (CAR T) re-directed to CD19, have induced remarkable responses in clinical trials for patients with B-cell malignancies. Patients have responded to therapy with a CAR T dose which is a fraction of the pre-existing tumor burden. Explanations for this observation include studies which show the proliferative potential of the CAR T cells (Kalos M et al Sci Transl Med 2011), as well as our recent study which showed that individual CAR T cells can serial kill tumor cells (Davenport AJ et al CIR 2015, Figure 6). Using our dual antigen receptor model (OT-I T cell receptor and 2nd generation HER-2 CAR in the same T cell, termed CAR.OTI cells), we also observed a reproducible and significantly shorter time from CAR- vs TCR-mediated activation to detachment from dying tumor cells (Davenport AJ et al CIR 2015, Figure 4D)suggesting that CAR-mediated individual killing events are actually faster. To explore how this may occur, we examined the immune synapse structure at 20 minutes of CAR.OTI CTL co-culture with tumor cells expressing the cognate antigen for either the CAR or TCR. At this timepoint, CAR.OTI CTL, activated via the TCR, formed a conventional bull's eye immune synapse with accumulation of LCK and actin clearance (Figure 1). Surprisingly, CAR.OTI CTL activated via their CAR had an immune synapse with no or diffuse LCK and small actin rings (Figure 1). At the same timepoint, CAR-activated CAR.OTI CTL conjugates with tumor cells were characterized by a microtubule organizing center (MTOC) distant from the immune synapse LCK accumulation. In contrast TCR activated CAR.OTI CTL conjugates consistently had the MTOC proximal to the LCK accumulation (Figure 2A). Despite this, CAR-mediated CAR.OTI CTL killing of tumor targets was inhibited by a protein kinase C zeta inhibitor and is, therefore, MTOC dependent (Figure 2B). The MTOC circumnavigates the activated CTL nucleus and moves to the immune synapse, bringing cytotoxic granules with it. Using time lapse live video (TLLV) microscopy, we compared CAR.OTI CTL cytotoxic granule movement when the CAR.OTI were activated via the TCR vs CAR. We showed that following CAR vs TCR activation, CAR.OTI cytotoxic granules moved with a significantly higher velocity, and had a shorter time lapse to reach the immune synapse following activation (Ca2+ flux), and a significantly shorter time to detachment from the dying tumor cell (Figure 2C). We then re-examined immune synapse formation at an earlier timepoint, to explore whether the data from Figures 1-2 could be explained by a more rapid CTL response following CAR-mediated signaling. In contrast to our observations at 20 minutes, at five minutes we showed CAR-activated CAR.OTI CTL formed conjugates with tumor targets and the immune synapse showed distinct LCK accumulation and actin clearance (Figure 3A). Finally, we explored CAR.OTI CTL signaling and showed that CAR-mediated activation induced a significantly lower number of Ca2+ fluxes, however each Ca2+ flux amplitude was not different (Figure 3B). We also examined changes in proximal (phospho-LCK, pLCK) and distal (phospho-ERK, pERK) signals in CAR- versus TCR- activated CAR.OTI cells, and showed that CAR-mediated activation induced more rapid proximal and distal activation signals (Figure 3C). In conclusion, this study showed that compared to activation by TCR ligation, T cells respond to CAR ligation with faster phospho-protein signaling, Ca2+ flux, formation of an immune synapse and a more rapid movement of the MTOC and delivery of the cytotoxic granules to kill the tumor cells. Furthermore, LFA-1 did not accumulate at the immune synapse following CAR activation, therefore, reduced adhesion may facilitate the observed rapid detachment from the dying tumor cell, and enable the CAR T to rapidly move onto the next tumor target for 'bigger, stronger, faster' killing. Disclosures No relevant conflicts of interest to declare.

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P07.02 High-affinity TCRs specific for cancer testis antigens as a therapy for multiple myeloma and solid tumors

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-itoc7.96 ◽

2020 ◽

Vol 8 (Suppl 2) ◽

pp. A49.1-A49

Author(s):

MAJ de Rooij ◽

DM van der Steen ◽

D Remst ◽

A Wouters ◽

M van der Meent ◽

...

Keyword(s):

Multiple Myeloma ◽

T Cells ◽

T Cell ◽

Tumor Cell ◽

Cross Reactivity ◽

Tumor Cell Lines ◽

High Affinity ◽

Cancer Testis Antigens ◽

Efficient Recognition ◽

Cancer Testis

BackgroundCancer Testis Antigens (CTAs) are highly expressed in multiple different tumor types, but silent in normal tissue, except the testis. This tumor-restricted expression pattern makes them an ideal target for adoptive T-cell therapy. However, the responsiveness in clinical setting may be hampered because high-affinity T cells against self-antigens presented in the context of self-HLA are deleted in the thymus by negative selection. In this study, we aim to identify high-affinity T cell receptors (TCRs) specific for CTAs from the allogeneic-HLA repertoire.Materials and MethodsIn this study, HLA class I binding peptides derived from different CTA genes were identified by HLA-peptide elution experiments and subsequent mass spectrometric analysis. From the identified peptides HLA tetramers were generated to isolate peptide specific CD8+ T cells from healthy allogeneic donors. Efficacy and safety of the TCRs was determined by various different stimulation assays. The most potent TCRs were sequenced, analyzed and transduced into peripheral CD8+ and CD4+ T cells to confirm CTA specific cytokine production and cytotoxicity.ResultsMAGE and CTAG peptides were eluted from multiple myelomas, EBV-transformed lymphoblastic cells, acute myeloid leukemia and ovarium carcinomas. We selected TCRs recognizing 3 different MAGE-A1 peptides in the context of HLA-A*02:01, HLA-A*03:01 and HLA-B*07:02. Furthermore, we selected TCRs specific for MAGE-A3 in the context of HLA-B*35:01 and HLA-A*01:01; TCRs specific for MAGE-A9 in the context of HLA-A*01:01 and TCRs specific for CTAG1 in the context of HLA-A*02:01. The selected T-cell clones demonstrated efficient recognition of MAGE-A1, MAGE-A3 or CTAG1 positive multiple myeloma and solid tumor cell lines without detectable cross-reactivity.ConclusionsWe identified multiple different TCRs from the allogeneic-HLA repertoire specific for CTA genes. These TCRs demonstrate efficient recognition and killing of CTA positive multiple myeloma and solid tumor cell lines and did not show any cross-reactivity. The peptides recognized by the TCRs are presented in different HLA alleles. Since, 71% of the world population contains one of these HLA-alleles, a large percentage suffering from a MAGE or CTAG positive tumor could potentially be treated with the identified TCRs by TCR-gene therapy.Disclosure InformationM.A.J. de Rooij: None. D.M. van der Steen: None. D. Remst: None. A. Wouters: None. M. van der Meent: None. R.S. Hagedoorn: None. M.G.D. Kester: None. P.A. van Veelen: None. F.J.H. Falkenburg: None. M.H.M. Heemskerk: None.

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A CD3 x FRα T-cell engaging bispecific antibody for efficient killing of ovarian cancer cells with minimal cytokine release.

Journal of Clinical Oncology ◽

10.1200/jco.2020.38.15_suppl.e18050 ◽

2020 ◽

Vol 38 (15_suppl) ◽

pp. e18050-e18050

Author(s):

Ben Buelow ◽

Brian Avanzino ◽

Aarti Balasubramani ◽

Andrew Boudreau ◽

Laura Davison ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Tumor Cell ◽

Tumor Cells ◽

Cytokine Production ◽

Cell Cytotoxicity ◽

Cytokine Release ◽

Limited Efficacy ◽

Human T Cells

e18050 Background: Ovarian Cancer (OvCa) is the leading cause of gynecologic cancer mortality in women. Since the introduction of platinum-based chemotherapy there has been little change in the prognosis of OvCa patients, with < 30% overall survival in advanced disease, creating an urgent medical need for novel therapies. Few ovarian epithelium-specific surface proteins are suited for Ab targeting. However, studies have shown folate receptor α (FRα) to be highly over-expressed in OvCa; expression level and stage correlate, and FRα is absent or minimally expressed in normal tissues. However, naked Ab therapy has shown limited efficacy while CAR-T therapy has been plagued by toxicity and limited efficacy. ADCs have demonstrated some activity but present the risk of toxin-mediated side effects. Using Teneobio’s unique antibody discovery platform, we have developed a CD3 x FRα T-BsAb that retains the potent cytotoxicity of other T-cell redirecting therapies but with significantly reduced cytokine release. Methods: Antibodies targeting CD3 and FRα were generated via immunization of our proprietary transgenic animals. Candidate antibodies were selected by repertoire deep sequencing of B-cells from draining lymph nodes, high-throughput gene assembly, recombinant expression, and functional screening. Bispecific antibodies targeting CD3 and FRα were assembled and evaluated for their ability to selectively activate primary human T-cells and mediate killing of FRα+ tumor cells in vitro and in vivo. T-cell activation surface markers, cytokine production and tumor cell cytotoxicity were measured. Results: Primary human T-cells were activated only in the presence of both the CD3 x FRα T-BsAb and FRα (either recombinant or cell-surface protein). Potent and selective cytotoxicity against FRα+ tumor cells was observed in co-cultures of primary human T-cells and OvCa tumor cell lines. Strikingly, our T-BsAb mediated comparable tumor cell cytotoxicity to CD3 x FRα T-BsAbs containing a high affinity anti-CD3 domain but with significantly reduced cytokine production. Our Ab showed preliminary evidence of tumor growth inhibition in xenograft models of OvCa in vivo. Conclusions: We have created a novel CD3 x FRα T-BsAb that mediates T-cell killing of FRα+ tumor cells with minimal production of cytokines. This molecule may improve safety, efficacy, and offer opportunities for combination therapy to treat OvCa.

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CD33 BiTE ® Construct Mediated Immunological Synapse Formation and Downstream Signaling in T Cells Is Dependent on Expression of Costimulatory Molecules on Target Cells

Blood ◽

10.1182/blood-2021-146488 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 2237-2237

Author(s):

Anetta Marcinek ◽

Bettina Brauchle ◽

Gerulf Hänel ◽

Sonja M Lacher ◽

Nora Zieger ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Research Funding ◽

Synapse Formation ◽

Costimulatory Molecules ◽

Target Cells ◽

Immune Synapse ◽

Downstream Signaling ◽

Signaling Receptors

Abstract BiTE ® (Bispecific T-cell Engager) constructs represent a novel immunotherapeutic strategy that recruits T cells against cancer cells independent of their TCR specificity. Currently, two CD33xCD3 BiTE ® antibody constructs (AMG 330 & AMG 673) are being investigated in phase I dose escalation trials in patients with relapsed/refractory Acute Myeloid Leukemia (AML) with early evidence of acceptable safety and anti-leukemic activity (Ravandi et al., ASH 2020; Subklewe et al., EHA 2020). So far, details of BiTE ® mediated T-cell engagement and information on parameters contributing to their efficacy need more investigation. Therefore, we aimed to characterize the interplay between target and effector cells to deepen our mechanistic understanding of BiTE ® construct mediated T-cell engagement. Previously, we have created a novel in vitro model system with murine Ba/F3 cells expressing human (hu) CD33 ± huCD80 ± huCD86 ± huPD-L1 to study T-cell proliferation and cytotoxicity induced by AMG 330. Using that system, we showed that expression of T-cell co-signaling receptors on target cells modulate AMG 330 induced T-cell activity (Marcinek et al., ASH 2018, EHA 2019). Here, we hypothesize that expression of costimulatory molecules impacts BiTE ® mediated immune synapse formation and consecutive downstream signaling in BiTE ® construct activated T cells. To study whether AMG 330 can induce synapse formation and TCR triggering we used a previously described reconstituted T-cell system, which consists of non-immune (HEK) cells introduced with genes encoding the TCR and other proteins (e.g. CD45) required for the regulation of TCR phosphorylation (James et al., Nature 2012). HEK-T cells were incubated with huCD33 transduced RajiB cells in presence of fluorescently labeled AMG 330 or a control BiTE® (cBiTE) construct to allow cell conjugation. A spinning disc confocal microscope system was used to image cells. To pinpoint the role of T-cell co-signaling receptors in immune synapse formation we incubated differentBa/F3 cell constructs or primary AML (pAML) cells with healthy donor T cells in the presence of AMG 330 and analyzed intensity of LFA-1 expression within the synapse using an Imaging Flow Cytometer. Furthermore, we determined phosphorylation of ZAP70, AKT and ERK in conjugated T cells after various time points by phosphoflow cytometry. We observed that AMG 330, in contrast to cBiTE®, induced TCR triggering reflected by exclusion of CD45 from the RajiB-T-cell-interface. Simultaneously clustering of CD33 occurred in AMG 330 induced cell-cell-interfaces (Fig. 1A/B). The percentage of conjugates formed with huCD33 + Ba/F3 cells was significantly higher in constructs expressing huCD86, compared to those expressing no costimulatory antigens or additional huPD-L1 (Mean % in huCD33 + Ba/F3: 2.8 vs. huCD33 + CD86 +.Ba/F3: 4.2 [p=0.0031] vs. huCD33 + huCD86 + PD-L1 + Ba/F3: 2.8 [p=0.0018]). This was accompanied by LFA-1 accumulation within the T-cell-Ba/F3 cell synapse (Mean of MFI in huCD33 + CD86 +.Ba/F3: 10,933 > huCD33 + huCD86 + PD-L1 + Ba/F3: 7,749 > huCD33 + Ba/F3: 7,028). For downstream signaling in T cells after engagement with Ba/F3 cell constructs in the presence of AMG 330, we observed that kinase phosphorylation was highest after 10 minutes in CD86 co-expressing Ba/F3 cells (Mean % of phosphorylation in T-cell conjugates with huCD33 + vs huCD33 + huCD86 + vs huCD33 + CD86 +.PD-L1 + Ba/F3: pERK 40.9 vs 54.3 [p=0.0064] vs 51.2 %; pAKT: 69.1 vs 81.5 [p=0.0642] vs 75.1 %; pZAP70: 6.9 vs 12.2 [p<0.0001] vs 7.7 % [p<0.0001]) (Fig. 1C). Finally, we evaluated if these finding could also be observed in pAML samples. For that, we determined LFA-1 expression intensity within AMG 330-induced pAML-T-cell synapses. We used CD33 + pAML samples with either high CD86 and no PD-L1 expression or vice versa. Comparing synapse formation between these samples, LFA-1 intensity was 4.6-fold higher in the CD86 + PD-L1 - sample compared to the CD86 - PD-L1 + pAML. Taken together, our data unravel molecular mechanisms of BiTE® construct induced immune synapse formation, highlighting the role of costimulatory molecules in this process. They support the notion that T cell co-signaling receptors like CD86 and PD-L1 modulate T-cell response in an early event manner. Prospective analyses in clinical trials are needed to validate the relevance of checkpoint molecule expression on target cells as a potential predictive biomarker for response. Figure 1 Figure 1. Disclosures Brauchle: Adivo: Current Employment. Lacher: Roche: Research Funding. Kischel: Amgen GmbH Munich: Current Employment. von Bergwelt: Roche: Honoraria, Research Funding, Speakers Bureau; Miltenyi: Honoraria, Research Funding, Speakers Bureau; Mologen: Honoraria, Research Funding, Speakers Bureau; Kite/Gilead: Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau; Astellas: Honoraria, Research Funding, Speakers Bureau; MSD Sharpe & Dohme: Honoraria, Research Funding, Speakers Bureau; BMS: Honoraria, Research Funding, Speakers Bureau. Theurich: Amgen: Consultancy, Honoraria; BMS/Celgene: Consultancy, Honoraria; GSK: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Buecklein: Novartis: Consultancy, Other: congress and travel support, Research Funding, Speakers Bureau; Pfizer: Consultancy, Honoraria, Speakers Bureau; Miltenyi: Research Funding; Kite/Gilead: Consultancy, Honoraria, Other: Congress and travel support, Research Funding; BMS/Celgene: Consultancy, Research Funding; Amgen: Consultancy, Honoraria. Subklewe: Janssen: Consultancy; Seattle Genetics: Consultancy, Research Funding; Roche: Research Funding; Novartis: Consultancy, Research Funding, Speakers Bureau; Pfizer: Consultancy, Speakers Bureau; Klinikum der Universität München: Current Employment; Takeda: Speakers Bureau; MorphoSys: Research Funding; Miltenyi: Research Funding; Gilead: Consultancy, Research Funding, Speakers Bureau; Amgen: Consultancy, Research Funding, Speakers Bureau; BMS/Celgene: Consultancy, Research Funding, Speakers Bureau.

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Local Activator and T Cell Engager (αBCMA x αPD-L1 x αCD3) with Enhanced Tumor Killing and Minimal Cytokine Release for the Treatment of Multiple Myeloma

Blood ◽

10.1182/blood-2020-136648 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 20-20

Author(s):

Melissa Vrohlings ◽

Stephanie Jungmichel ◽

Jan Müller ◽

David Senn ◽

Thomas Schleier ◽

...

Keyword(s):

Multiple Myeloma ◽

T Cells ◽

T Cell ◽

Tumor Cell ◽

Cell Lines ◽

T Cell Activation ◽

Research Funding ◽

Cell Activation ◽

Cytokine Release ◽

Private Company

BCMA-targeting bispecific T-cell engagers in clinical development have demonstrated encouraging preclinical efficacy. The most advanced of these is AMG 420, which showed significantly improved response rates in relapsed/refractory multiple myeloma (MM) patients. Nevertheless, median duration until relapse is currently limited to approximately 12 months, highlighting the need for new drugs with novel MoA. Recently, we reported on a Local Activator and T cell Engager (LocATE) antibody that targets BCMA and selectively blocks programmed death-ligand 1 (PD-L1) on malignant cells (ASCO, June 2019). LocATE induced superior T cell activation and cancer cell killing, in vitro and ex vivo, compared to a BCMAxCD3 BiTE alone or in combination with a PD-L1 inhibitor. Here, we sought to further characterize the novel MoA of our LocATE. To assess the therapeutic potential of the LocATE, we first investigated whether potent cytotoxicity is uncoupled from high levels of cytokine release. We evaluated three LocATE molecules with different PD-L1 affinities (low, medium, high). Using BCMA-expressing MM cell lines (U-266, MM.1S, RPMI-8226 and H929) with distinct PD-L1 surface expression levels (3 - 53%), we determined the cytokine profile (IL-2, IL-6, IFN-γ, TNF-α) and target cell lysis induced by each candidate in the presence of CD3-positive human T cells. All three candidates exhibited comparable killing potency, however, low-affinity PD-L1 LocATE antibodies induced significantly less cytokine release (up to 10-fold) than its higher PD-L1 affinity counterparts across all cell lines investigated. Notably, using the low-affinity PD-L1 LocATE, we observed a 2-fold increase in tumor cell killing compared to bispecific BCMAxCD3 targeting controls in cell lines expressing high PD-L1 levels (53%), underlining the contribution of PD-L1 inhibition. Accordingly, phenotypic profiling of effector cells showed that the LocATE more potently induced dose-dependent upregulation of the activation markers CD69, CD25 and HLA-DR compared to bispecific controls. Importantly, cytotoxic activity, T cell activation and cytokine release were not induced when BCMA-negative cells expressing high levels of PD-L1 were treated with LocATE, underlining the BCMA-selective killing mechanism. Since the superior efficacy of LocATE was found to correlate with the expression level of PD-L1 on MM cell lines and upregulation of PD-L1/PD-1 has been reported as one of the major myeloma cell escape mechanisms during treatment with BiTEs, we subsequently investigated the efficacy of LocATE using primary bone marrow samples and peripheral blood mononuclear cell (PBMCs) obtained from MM patients. Six bone marrow mononuclear cell (BMMC) and eight PBMC samples from MM donors of different disease stages were characterized for PD-1/PD-L1 expression levels; analysis of T cell frequency and level of activation/exhaustion was performed based on CD4, CD8, CD25, CD69, Tim-3, Lag-3 and PD-1 marker expression. Using patient samples with high frequencies of PD-1 expressing T cells prior to treatment, LocATE induced superior MM tumor cell lysis and T cell activation compared to BCMAxCD3 bispecific antibodies. No activity was observed on healthy cells, underlining the safe and selective killing mechanism through tumor-local reactivation of exhausted T cells. Collectively, these findings demonstrate that the simultaneous T cell redirection and tumor-specific checkpoint inhibition with the LocATE leads to an improved therapeutic index with robust tumor cell killing and low levels of cytokine release. Capable of counteracting adaptive immune resistance caused by increased PD-1/PD-L1 signaling, the LocATE antibody has the prospect to significantly improve survival for multiple myeloma patients. Disclosures Vrohlings: CDR-Life: Current Employment. Jungmichel:CDR-Life: Current Employment, Other: current option holder. Senn:CDR-Life: Current Employment. Schleier:CDR-Life: Current Employment, Current equity holder in private company. Scheifele:CDR-Life: Current Employment, Current equity holder in private company. Wendelspiess:CDR-Life: Current Employment. Leisner:CDR-Life: Current Employment, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees. Jaeger:CDR Life AG: Consultancy, Research Funding; Miltenyi: Consultancy, Honoraria; Karyopharm: Honoraria; BMS/Celgene: Consultancy, Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; AbbVie: Honoraria; F. Hoffmann-La Roche: Honoraria, Research Funding. Borras:CDR-Life: Current Employment, Current equity holder in private company.

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T Cell Bispecific Antibodies: An Antibody-Based Delivery System for Inducing Antitumor Immunity

Pharmaceuticals ◽

10.3390/ph14111172 ◽

2021 ◽

Vol 14 (11) ◽

pp. 1172

Author(s):

Daisuke Kamakura ◽

Ryutaro Asano ◽

Masahiro Yasunaga

Keyword(s):

T Cells ◽

Cell Death ◽

T Cell ◽

Tumor Cell ◽

Tumor Cells ◽

T Cell Activation ◽

Antitumor Immunity ◽

Bispecific Antibodies ◽

Tumor Site ◽

Tumor Cell Death

As a breakthrough immunotherapy, T cell bispecific antibodies (T-BsAbs) are a promising antibody therapy for various kinds of cancer. In general, T-BsAbs have dual-binding specificity to a tumor-associated antigen and a CD3 subunit forming a complex with the TCR. This enables T-BsAbs to crosslink tumor cells and T cells, inducing T cell activation and subsequent tumor cell death. Unlike immune checkpoint inhibitors, which release the brake of the immune system, T-BsAbs serve as an accelerator of T cells by stimulating their immune response via CD3 engagement. Therefore, they can actively redirect host immunity toward tumors, including T cell recruitment from the periphery to the tumor site and immunological synapse formation between tumor cells and T cells. Although the low immunogenicity of solid tumors increases the challenge of cancer immunotherapy, T-BsAbs capable of immune redirection can greatly benefit patients with such tumors. To investigate the detailed relationship between T-BsAbs delivery and their T cell redirection activity, it is necessary to determine how T-BsAbs deliver antitumor immunity to the tumor site and bring about tumor cell death. This review article discusses T-BsAb properties, specifically their pharmacokinetics, redirection of anticancer immunity, and local mechanism of action within tumor tissues, and discuss further challenges to expediting T-BsAb development.

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Local activator and T cell engager (LocATE) selectively blocks PD-L1 at the cytolytic synapse for deeper responses in multiple myeloma.

Journal of Clinical Oncology ◽

10.1200/jco.2019.37.15_suppl.8045 ◽

2019 ◽

Vol 37 (15_suppl) ◽

pp. 8045-8045 ◽

Cited By ~ 1

Author(s):

Christian Leisner ◽

Leonardo Borras ◽

Stephanie Jungmichel ◽

Philipp Richle ◽

Fabian Scheifele ◽

...

Keyword(s):

Multiple Myeloma ◽

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Fold Increase ◽

Checkpoint Inhibition ◽

Bone Marrow Biopsies ◽

Immune Synapse

8045 Background: The BCMA-targeting bispecific T-cell engager AMG420 emerged as the first bispecific that achieved responses similar to CAR-T therapies in patients with relapsed/refractory (RR) multiple myeloma (MM). Despite improved ORR, the median duration until relapse is currently limited to approximately 12 months. Persistent minimal residual disease drives relapse and is characterized by increased expression of PD-1/PD-L1. Efficacy with checkpoint inhibitors is compromised by 1) their activity not been targeted specifically to the immune synapse between T cells and cancer cells, and 2) dose-limiting broadly distributed immune-related adverse events, which has halted several clinical trials. This underscores the need for localized checkpoint inhibition within the cytolytic synapse. We developed a Local Activator and T cell Engager (LocATE) antibody that combines binding to CD3 and BCMA with selective blockade of PD-L1 at the immune synapse in just one scaffold. Selectivity is achieved via low afffinity for PD-L1 and high affinity for BCMA. Methods: Antibody mediated Cytotoxicity (LDH assay) and T cell activation (IL-2 release) was measured in vitro using MM cell lines together with isolated human CD3+ T cells. Human ex vivo T cell activity and redirection was evaluated on fresh bone marrow biopsies from MM patients with different disease stages by automated microscopy (pharmacoscopy) and image analysis. Results: The LocATE antibody showed a 5-fold increase in T cell activation and MM cell killing in vitro compared to a BCMAxCD3 BiTE. Furthermore, patient-derived MM cells showed up to a 19-fold increase in T cell activation as compared to a BCMAxCD3 BiTE or a combination of BiTE and PD-L1 inhibitor, while no activity was observed on healthy cells. Conclusions: These results suggest that T cell redirection with simultaneous checkpoint inhibition in the synapse is highly potent while minimizing off-tumor toxicity, therefore, has high therapeutic potential for patients with relapsed MM.

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Multiple Myeloma as Target for γδ T Cell Mediated Immunotherapy - Expression of the Putative Vγ9Vδ2-TCR Ligand F1-ATPase on Myeloma Cells.

Blood ◽

10.1182/blood.v106.11.3391.3391 ◽

2005 ◽

Vol 106 (11) ◽

pp. 3391-3391

Author(s):

Volker Kunzmann ◽

Judith Engert ◽

Brigitte Kimmel ◽

Martin Wilhelm ◽

Hermann Einsele

Keyword(s):

T Cells ◽

T Cell ◽

Tumor Cell ◽

Tumor Cells ◽

Cell Lines ◽

Surface Expression ◽

Tumor Cell Lines ◽

Myeloma Cells ◽

F1 Atpase ◽

Vγ9vδ2 T Cells

Abstract Activated Vγ9Vδ2 T cells, the major γδ T lymphocyte subset in humans, show cytolytic activity against various tumor cells. However, tumor antigens recognized by the TCR remained unkown so far. Recently, the ectopic surface expression of the F1-ATPase, normally expressed on the internal membrane of mitochondria, was implicated in tumor recognition of Vγ9Vδ2 T cells (Scotet E. et al., Immunity2005; 22:71–80). Surface expression of the a chain of the F1-ATPase (recognized by monoclonal antibody 7H10) strongly correlates with susceptibility of tumor cells against Vγ9Vδ2 T cell lysis. Different functions have been attributed to the ectopic expression of the F1-ATPase on the cell surface, including an immunoregulatory role induced by cell stress, receptor for angiostatin or regulation of lipoprotein transport through high-affinity apolipoprotein A-I binding. In this study we evaluated the surface expression of this F1-ATPase on hematopoetic tumor cell lines and on primary tumor cells from hematological malignancies. As already shown, the a subunit of F1-ATPase was clearly detected on several tumor cell lines which are consistently killed by activated Vγ9Vδ2 T cells (Daudi, K562, RPMI 8226), whereas the known Vγ9Vδ2 T cell resistant tumor cell lines (Raji, Jurkat) did not express detectable levels of the F1-ATPase. Analysis of 42 primary hematopoetic tumor cells (21 myeloma, 17 AML, 4 B-NHL) revealed frequent expression of F1-ATPase on primary myeloma cells (14/19 positive), whereas primary AML blasts (3/17 positive) and primary NHL cells (1/4 positive) expressed the putative Vγ9Vδ2-TCR ligand F1-ATPase less frequently. To further evaluate the functional role of F1-ATPase expression in Vγ9Vδ2 T cell mediated recognition of myeloma cells, cytotoxicity assays were performed. The mAb against the a subunit of F1-ATPase significantly decreased in vitro lysis of myeloma cells lines and primary myeloma cells by activated Vγ9Vδ2 T cells. These results suggests Vγ9Vδ2 TCR-dependent interactions between myeloma cells and Vγ9Vδ2 T cells and indicate that multiple myeloma should be considered as a major target for γδ T-cell mediated immunotherapy.

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