A novel, native-format bispecific antibody triggering T-cell killing of B-cells is robustly active in mouse tumor models and cynomolgus monkeys

BackgroundImmune checkpoint inhibitors have demonstrated durable clinical responses and an increase in overall survival for some patients with cancer. Next generation cancer immunotherapies, such as tumor necrosis factor receptor superfamily (TNFRSF) agonists, have potential to further improve on this success. FS120 is a tetravalent bispecific antibody targeting OX40 and CD137 (4-1BB), currently being evaluated in a Phase I clinical trial (NCT04648202). FS120 activates CD4+ and CD8+ T cells by concurrent binding to both targets via an FcgR-independent mechanism [1]. In preclinical tumor models, FS120 induced T cell proliferation and cytokine production associated with significant tumor regression, better than that observed with a monoclonal antibody combination. Here, we demonstrate the ability of FS120 to improve anti-PD-1 induced T cell activity, increasing tumor growth inhibition and survival, in syngeneic mouse tumor models, compared to monotherapy.MethodsFS120 < i >in vitro</i > activity in combination with anti-PD-1 was assessed by utilizing staphylococcal enterotoxin A (SEA) superantigen assays and mixed leukocyte reaction (MLR) assays. An anti-mouse OX40/CD137 bispecific antibody (FS120 surrogate) was tested in CT26 syngeneic mouse tumor models in combination with an anti-mouse PD-1 antibody to assess efficacy and pharmacodynamic endpoints, including T cell proliferation by < i>ex vivo</i> flow cytometry and serum cytokine levels.ResultsFS120 in combination with anti-PD-1 enhanced primary human T cell activity, when compared to either monotherapy, in both SEA and MLR assays. FS120 surrogate significantly improved survival of CT26 tumor-bearing mice treated with anti-mPD-1 antibody. FS120 surrogate and anti-PD-1 combination significantly enhanced serum interferon-gamma levels and increased proliferating granzyme B+ CD8+ T cells in the blood of tumor-bearing mice, when compared to either monotherapy treatments.ConclusionsFS120 combination with anti-PD-1 enhances T cell activity in multiple human primary immune assays. In combination with anti-PD-1, FS120 surrogate increased the antitumor efficacy with pharmacodynamic changes related specifically to T cell activation, when compared to monotherapies. These data support the development of FS120 in combination with anti-PD-1 in patients with hard-to-treat cancers who may not benefit fully from either treatment as a monotherapy.ReferencesGaspar M, Pravin J, Rodrigues L, Uhlenbroich S, Everett K L, Wollerton F, Morrow M, Tuna M, Brewis N. CD137/OX40 Bispecific Antibody Induces Potent Antitumor Activity that Is Dependent on Target Coengagement. Cancer Immunol Res. 2020; (8) (6) 781–793Ethics ApprovalMurine studies were conducted under a U.K. Home Office License in accordance with the U.K. Animal (Scientific Procedures) Act 1986 and EU Directive EU 2010/63.

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843 Development and engineering of human sialidase for degradation of immunosuppressive sialoglycans to treat cancer

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2021-sitc2021.843 ◽

2021 ◽

Vol 9 (Suppl 3) ◽

pp. A884-A884

Author(s):

Li Peng ◽

Lizhi Cao ◽

Sujata Nerle ◽

Robert LeBlanc ◽

Abhishek Das ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Immune Cells ◽

First Generation ◽

Single Agent ◽

Mouse Tumor ◽

Cytokine Release ◽

Tumor Models ◽

Cell Immunity ◽

Mouse Tumor Models

BackgroundSialoglycans, a type of glycans with a terminal sialic acid, have emerged as a critical glyco-immune checkpoint that impairs antitumor response by inhibiting innate and adaptive immunity. Upregulation of sialoglycans on tumors has been observed for decades and correlates with poor clinical outcomes across many tumor types. We previously showed that targeted desialylation of tumors using a bifunctional sialidase x antibody molecule, consisting of sialidase and a tumor-associated antigen (TAA)-targeting antibody, has led to robust single-agent efficacy in mouse tumor models. In addition to tumor cells, most immune cells present substantially more abundant sialoglycans than non-hematological healthy cells, which may also contribute to immunosuppression. Therefore, we studied the impact of immune cell desialylation and evaluated the therapeutic potential of a newly developed sialidase-Fc fusion (Bi-Sialidase), which lacks a TAA-targeting moiety and consists of engineered human neuraminidase 2 (Neu2) and human IgG1 Fc region, in preclinical mouse tumor models.MethodsThe first generation Neu2 variant was further optimized to improve titers and stability to constructed Bi-Sialidase. Bi-Sialidase’s desialylation potency and impact on immune responses were studied in vitro using various human immune functional assays, including T-cell activation, allogeneic mixed lymphocyte reaction, antibody-dependent cellular cytotoxicity, macrophages polarization/activation, neutrophil activation, and peripheral blood mononuclear cell (PBMC) cytokine release assays. We evaluated its antitumor efficacy in mouse tumor models. Bi-Sialidase’s safety profile was characterized by conducting rat and non-human primate (NHP) toxicology studies.ResultsThe optimized Bi-Sialidase achieved a titer of 2.5 g/L from a 15-day fed-batch Chinese hamster ovary cell culture; in contrast, the wild-type and first-generation Neu2 had no production or a low titer (<0.1 g/L) under similar conditions, respectively. We demonstrated that Bi-Sialidase led to dose-dependent desialylation of immune cells and potentiated T-cell immunity, without impacting NK, macrophage, or neutrophil activation by desialylating immune cells. Activated and exhausted T cells upregulated surface sialoglycans and Bi-Sialidase-mediated desialylation reinvigorated exhausted-like T cells as measured by IFNg production. Bi-Sialidase treatment also enhanced DC priming and activation of naïve T cells by desialylating both T cells and DCs. Furthermore, Bi-Sialidase showed single-agent antitumor activity in multiple mouse tumor models, including MC38, CT26, A20, and B16F10. Importantly, Bi-Sialidase did not cause cytokine release in human PBMC assays and was tolerated to up to 100 mg/kg in rats and NHPs, demonstrating a wide safety margin.ConclusionsBi-Sialidase with an optimized Neu2 offers a novel immunomodulatory approach to enhancing T-cell immunity by desialylating immunosuppressive sialoglycans for cancer treatment.

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Bispecific anti-PD-1/PD-L1 antibody CTX-8371 to promote cellular clustering and PD-1 shedding, antitumor activity and tolerability.

Journal of Clinical Oncology ◽

10.1200/jco.2021.39.15_suppl.e15056 ◽

2021 ◽

Vol 39 (15_suppl) ◽

pp. e15056-e15056

Author(s):

Diana I. Albu ◽

Yan Qin ◽

Xianzhe Wang ◽

Vivian Li ◽

Taeg Kim ◽

...

Keyword(s):

T Cell ◽

Transgenic Mice ◽

T Cell Activation ◽

Cell Activation ◽

Mouse Tumor ◽

Tumor Models ◽

Cynomolgus Monkeys ◽

Range Finding

e15056 Background: Checkpoint blockade therapies targeting PD-1 and PD-L1 have shown great success for the treatment of various malignancies. However, a substantial fraction of patients with PD-L1-positive tumors remain unresponsive to these therapies. Novel therapy with significantly greater activity than the leading PD-1/PD-L1 inhibitors is expected to bring additional clinical benefit to patients. Here we describe the preclinical evaluation of CTX-8371, which combines anti-PD-1 and anti-PD-L1 monoclonal antibodies in one bispecific tetravalent molecule. Methods: The immune-enhancing activity of CTX-8371 was tested in vitro in T cell activation assays and tumor cell killing assay. CTX-8371 anti-tumor efficacy in vivo was assessed using mouse tumor cells expressing human PD-L1 implanted in transgenic mice humanized at the PD-1 and PD-L1 loci. CTX-8371 anti-tumor activity was also tested in xenograft tumor models. The mechanism of action of CTX-8371 was investigated in vitro using Jurkat cells expressing PD-1 or PD-L1, human PBMCs, and in vivo in tumor-bearing, chimeric PD-1/PD-L1 transgenic mice. CTX-8371 PK was determined in mice using an MSD ELISA-based assay and in cynomolgus monkeys using a qualified ELISA method. Dose range finding and toxicokinetic studies were performed in cynomolgus monkeys. Results: CTX-8371 potently enhanced T cell activation and function in vitro and showed curative efficacy as monotherapy in multiple solid tumor models, isografts or xenografts. Furthermore, CTX-8371 demonstrated superior anti-tumor efficacy compared to Keytruda or atezolizumab in checkpoint inhibitors-sensitive and resistant syngeneic mouse tumor models. Mechanistically, in addition to blocking PD-1 interaction with PD-L1, CTX-8371 bispecific antibody facilitated cell to cell bridging between cells expressing PD-1 and cells expressing PD-L1. Furthermore, we show that simultaneous binding of CTX-8371 to both PD-1 and PD-L1 resulted in long term PD-1 shedding. This suggests that CTX-8371 may prevent or overcome T cell exhaustion within the tumor microenvironment, thus providing additional advantage over existing therapies. Lastly, excellent tolerability was observed in non-human primates given 2 weekly drug infusions at up to 50 mg/kg dose. Conclusions: CTX-8371 displays multiple mechanisms of action over monoclonal PD1/PD-L1 blockade. These unique pharmacological properties of CTX-8371 could explain the enhanced T cell responses to tumor antigens and superior efficacy over current monoclonal antibody therapies. With favorable PK/PD and toxicology profiles in mice and cynomolgus monkeys, CTX-8371 warrants further advancement to clinical testing.

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Nonclinical evaluation of the combination of mouse IL-21 and anti- mouse CTLA-4 or PD-1 blocking antibodies in mouse tumor models.

Journal of Clinical Oncology ◽

10.1200/jco.2013.31.15_suppl.3019 ◽

2013 ◽

Vol 31 (15_suppl) ◽

pp. 3019-3019 ◽

Cited By ~ 2

Author(s):

Maria Jure-Kunkel ◽

Mark Selby ◽

Katherine Lewis ◽

Gregg Masters ◽

Jose Valle ◽

...

Keyword(s):

T Cell ◽

Antitumor Activity ◽

Nk Cell ◽

Phase Iii ◽

Tumor Growth Inhibition ◽

Clinical Activity ◽

Mouse Tumor ◽

Synergistic Activity ◽

Tumor Models ◽

Mouse Tumor Models

3019 Background: Interleukin 21 (IL-21), a γc chain family cytokine, is produced primarily by CD4+ T cells and has many effects on immune cells, including enhancing CD8+ T cell and NK cell proliferation and cytotoxicity. Recombinant IL-21 (rIL-21) therapy resulted in objective responses in ~20% of melanoma and renal cell carcinoma patients. In mouse models, monoclonal antibody (mAb) blockade of CTLA-4 prolongs antigen-specific T cell responses, while blockade of programmed death 1 (PD-1) reverses tumor induced T cell suppression. Ipilimumab, a CTLA-4 blocking mAb, significantly improved overall survival in patients with metastatic melanoma in 2 phase III trials, and in phase I studies a PD-1 blocking mAb (nivolumab) has antitumor activity in various cancers. Side effect profiles for each mAb have been related to their mechanism and are generally manageable. It was hypothesized that combination of IL-21 plus CTLA-4 or PD-1 blockade may enhance antitumor responses, potentially leading to improved clinical activity. Methods: Preclinical studies were conducted to test the antitumor activity of mouse IL-21 (mIL-21) in combination with an anti-mouse PD-1 (mPD-1) mAb (4H2-IgG1) or with an anti-mCTLA-4 blocking mAb (9D9-IgG2b) in syngeneic mouse tumor models, including MC38, CT-26, EMT-6, and B16F10. mIL-21 was tested at doses ranging from 50-200 μg/dose, administered up to 3d/wk. mCTLA-4 mAb or mPD-1 mAb were administered 3-4x total at 200-300 μg/dose. Results: Combination treatments produced enhanced antitumor activity vs. monotherapy. In the MC38 model, mIL-21 treatment led to 30% median tumor growth inhibition (TGI) by d29, while mPD-1 mAb produced 60% median TGI and 1/10 tumor-free mice. Combination of both agents led to synergistic antitumor activity, with complete regressions (CR) in 7/10 mice and 99.9% median TGI (p=0.046). CTLA-4 mAb + mIL-21 also produced synergistic activity in the MC38 model. By d21, mIL-21 monotherapy induced 34% TGI while CTLA-4 mAb resulted in 28% TGI, with no CR in either group. Combination resulted in 6/8 mice with CR and 86% TGI (p<0.05). Conclusions: These results support the use of rIL-21+nivolumab and rIL-21+ipilimumab in recently initiated clinical trials.

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CRISPitope: A generic platform to model target antigens for adoptive T cell transfer therapy in mouse tumor models

STAR Protocols ◽

10.1016/j.xpro.2021.101038 ◽

2022 ◽

Vol 3 (1) ◽

pp. 101038

Author(s):

Maike Effern ◽

Nicole Glodde ◽

Emma Bawden ◽

Jana Liebing ◽

Daniel Hinze ◽

...

Keyword(s):

T Cell ◽

Mouse Tumor ◽

Cell Transfer ◽

Tumor Models ◽

Adoptive T Cell Transfer ◽

T Cell Transfer ◽

Mouse Tumor Models

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Finding the right balance: aOX40 immunotherapy enhances effector T cell function without impairing regulatory T cells intrinsic suppressive capacity in mouse tumor models

Journal for ImmunoTherapy of Cancer ◽

10.1186/2051-1426-3-s2-p77 ◽

2015 ◽

Vol 3 (S2) ◽

Author(s):

Amy Moran ◽

Fanny Polesso ◽

Minhazur Sarker ◽

David Parker ◽

Susan E Murray ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Regulatory T Cells ◽

Cell Function ◽

Mouse Tumor ◽

Tumor Models ◽

Effector T Cell ◽

Suppressive Capacity ◽

The Right ◽

Mouse Tumor Models

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PD-1 blockade enhances elotuzumab efficacy in mouse tumor models

Blood Advances ◽

10.1182/bloodadvances.2017004382 ◽

2017 ◽

Vol 1 (12) ◽

pp. 753-765 ◽

Cited By ~ 24

Author(s):

Natalie A. Bezman ◽

Amy Jhatakia ◽

Alper Y. Kearney ◽

Ty Brender ◽

Mark Maurer ◽

...

Keyword(s):

T Cell ◽

Antitumor Activity ◽

Mouse Models ◽

Cell Activity ◽

Antitumor Efficacy ◽

Mouse Tumor ◽

Tumor Models ◽

Key Points ◽

Mouse Tumor Models

Key PointsThe combination of elotuzumab and an anti–PD-1 antibody leads to enhanced antitumor efficacy in mouse models. Enhanced antitumor activity is likely due to the promotion of tumor-infiltrating NK and T-cell activity.

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Role of the immunoglobulin constant region in the antitumor activity of antibodies to cytotoxic T-lymphocyte antigen-4 (CTLA-4).

Journal of Clinical Oncology ◽

10.1200/jco.2013.31.15_suppl.9055 ◽

2013 ◽

Vol 31 (15_suppl) ◽

pp. 9055-9055

Author(s):

Alan J. Korman ◽

John Engelhardt ◽

Vafa Shahabi ◽

Roumyana Yordanova ◽

Karla Henning ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Antitumor Activity ◽

Phase Iii ◽

Mouse Tumor ◽

Constant Region ◽

Tumor Site ◽

Tumor Models ◽

Mouse Tumor Models

9055 Background: Anti-CTLA-4 therapy enhances antitumor T-cell responses by both cell-intrinsic and cell-extrinsic mechanisms. Effector T-cell (Teff) activation is increased directly by interfering with CTLA-4-B7 interactions that negatively regulate T cells and by interfering with CTLA-4 expressed on regulatory T cells (Tregs), which function to inhibit immune responses. To analyze in greater detail the mechanism of action of anti-CTLA-4 antibodies (Abs), we examined the role of the immunoglobulin constant region in the antitumor activity of anti-CTLA-4 Abs in mouse tumor models. Methods: The activity of anti-CTLA-4 Abs with different mouse IgG constant regions were compared in several mouse tumor models, and intratumoral and peripheral T cells were analyzed by FACS. DNA samples from 488 patients with metastatic melanoma who received ipilimumab in a phase III clinical trial, MDX010-20, were analyzed for polymorphisms in the IgG fragment c receptor (FcR) at FCGR3A (V158F) and FCGR2A (H131R) loci. Results: In subcutaneous MC38 and CT26 colon tumor models, an anti-CTLA-4 Ab containing the mouse IgG2a constant region exhibited enhanced antitumor activity compared to an anti-CTLA-4 Ab containing the IgG2b constant region, while anti-CTLA-4 Abs containing mouse IgG1 or a mutated mouse IgG1 D265A constant region showed no activity. Anti-CTLA-4-IgG2a caused a dramatic reduction of Tregs at the tumor site that resulted in a greater Teff/Treg ratio. In contrast, all isotypes resulted in expansion of Tregs in the periphery. These results point to an important role for FcR in the action of anti-CTLA-4 Abs. In patients from study MDX010-20, there was no association between the 2 FcR polymorphisms (FCGR3A and FCGR2A) and overall survival. Conclusions: These preclinical studies reveal a novel dual activity of anti-CTLA-4 Abs consisting of intratumoral reduction of Tregs together with activation of Teff cells. This effect is mediated by the constant region and is presumably due to antibody-dependent cellular cytotoxicity. The data suggest that FcR-bearing cells at the tumor site, as well as the presence of intratumoral Tregs, may be important factors in the antitumor activity of anti-CTLA-4 Abs.

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