Abstract 2577: RLI, a sushi-IL-15Rα/IL-15 fusion protein, is a potent immunomodulatory agent on NK and CD8+ T cells and synergizes with anti-PD1 treatment in preclinical mouse tumor models

e14546 Background: The efficacy and safety of recombinant human IL-2 (rhIL-2; Proleukin) to treat certain cancers is limited by a short half-life, marked toxicity and selective high affinity binding to IL2Ra over IL2Rb, resulting in preferential activation of suppressive Tregs. In contrast, MDNA11 has been engineered as a long-acting IL-2 superkine with high affinity IL2Rb receptor selectivity, resulting in preferential anti-cancer effector immune cell activation. Methods: MDNA11 was characterized in both in vitro and in vivo studies including assessment of receptor binding kinetics using BLI/Octet, receptor-mediated signaling in human PMBCs, efficacy in syngeneic mouse tumor models including memory response, as well as safety and PK/PD assessments in non-human primates (NHP). Results: Unlike rhIL-2, MDNA11 does not bind to human IL2Ra but demonstrates a 30-fold higher affinity binding to human IL2Rb. This selectivity resulted in enhanced in vitro STAT5 signaling in human NK and resting CD8 T cells with diminished signaling in Tregs; validation studies in humanized mice are ongoing. In CT26 and MC38 syngeneic tumor models, MDNA11 demonstrates potent and durable efficacy as monotherapy following a Q1W dose schedule for 2 weeks. Synergy with anti-PD1 and anti-CTLA4 immune checkpoint inhibitors (ICIs) was observed and a robust immune memory response developed in all mice with complete tumor clearance. These mice were protected against relapse and tumor re-challenges for up to 8 months without any further treatment, and showed the presence of antigen-specific CD8 T cells. In binding studies with IL-2 receptors of different species, MDNA11 showed highly similar affinity towards human and cynomolgus IL2Rb, confirming the latter as a highly relevant model for toxicology study. MDNA11 was well tolerated in cynomolgus monkeys up to 0.6 mg/kg, while inducing durable (≥10 days) proliferation and expansion of NK and CD8 T cells. Effects on Tregs were minimal and there was no eosinophilia and hypotension (associated with vascular leak syndrome). At high doses of MDNA11, the most common clinical observations were transient loss of appetite and diarrhea. There was modest increase in levels of IFNg and TNFa, but no sign of cytokine release syndrome. Dosing did not trigger development of anti-drug antibodies or histopathologic evidence of pulmonary edema (a major IL-2 induced toxicity). Conclusions: MDNA11 is a long-acting IL-2 superkine that exhibits robust efficacy in mouse tumor models as a single agent and was synergistic in combination with ICIs (anti-CTLA4 and anti-PD1). In NHP, MDNA11 demonstrates selective immune effector cell activation and a favorable safety profile. These data constitute a strong framework for the design of a pivotal GLP toxicology study to further support the planned clinical study of MDNA11 either as a single agent or in combination with ICIs.

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Abstract B94: Targeted ablation of FoxP3+ T cells activates peripheral and tumor-infiltrating cytotoxic CD8+ T cells in multiple syngeneic mouse tumor models

10.1158/2326-6074.tumimm18-b94 ◽

2020 ◽

Author(s):

Yingyun Wang ◽

Teresita Delfino ◽

Jill M. Schartner ◽

Sascha Rutz

Keyword(s):

T Cells ◽

Cd8 T Cells ◽

Mouse Tumor ◽

Tumor Models ◽

Syngeneic Mouse ◽

Mouse Tumor Models

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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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Tumor suppression of novel anti–PD-1 antibodies mediated through CD28 costimulatory pathway

Journal of Experimental Medicine ◽

10.1084/jem.20182359 ◽

2019 ◽

Vol 216 (7) ◽

pp. 1525-1541 ◽

Cited By ~ 9

Author(s):

Craig Fenwick ◽

Juan-Luis Loredo-Varela ◽

Victor Joo ◽

Céline Pellaton ◽

Alex Farina ◽

...

Keyword(s):

T Cells ◽

Antitumor Activity ◽

Cd8 T Cells ◽

Tumor Suppression ◽

Tumor Model ◽

Mouse Tumor ◽

The Novel ◽

Evolutionarily Conserved ◽

Mouse Tumor Models ◽

Costimulatory Pathway

Classical antagonistic antibodies (Abs) targeting PD-1, such as pembrolizumab and nivolumab, act through blockade of the PD-1–PDL-1 interaction. Here, we have identified novel antagonistic anti–PD-1 Abs not blocking the PD-1–PDL-1 interaction. The nonblocking Abs recognize epitopes on PD-1 located on the opposing face of the PDL-1 interaction and overlap with a newly identified evolutionarily conserved patch. These nonblocking Abs act predominantly through the CD28 coreceptor. Importantly, a combination of blocking and nonblocking Abs synergize in the functional recovery of antigen-specific exhausted CD8 T cells. Interestingly, nonblocking anti–PD-1 Abs have equivalent antitumor activity compared with blocker Abs in two mouse tumor models, and combination therapy using both classes of Abs enhanced tumor suppression in the mouse immunogenic tumor model. The identification of the novel nonblocker anti–PD-1 Abs and their synergy with classical blocker Abs may be instrumental in potentiating immunotherapy strategies and antitumor activity.

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CD4+ T Cells Play a Critical Role in the Generation of Primary and Memory Antitumor Immune Responses Elicited by SA-4-1BBL and TAA-Based Vaccines in Mouse Tumor Models

PLoS ONE ◽

10.1371/journal.pone.0073145 ◽

2013 ◽

Vol 8 (9) ◽

pp. e73145 ◽

Cited By ~ 22

Author(s):

Rajesh K. Sharma ◽

Esma S. Yolcu ◽

Abhishek K. Srivastava ◽

Haval Shirwan

Keyword(s):

T Cells ◽

Immune Responses ◽

Cd4 T Cells ◽

Critical Role ◽

Mouse Tumor ◽

Tumor Models ◽

Mouse Tumor Models

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A nonclassical non-Vα14Jα18 CD1d-restricted (type II) NKT cell is sufficient for down-regulation of tumor immunosurveillance

Journal of Experimental Medicine ◽

10.1084/jem.20051381 ◽

2005 ◽

Vol 202 (12) ◽

pp. 1627-1633 ◽

Cited By ~ 191

Author(s):

Masaki Terabe ◽

Jeremy Swann ◽

Elena Ambrosino ◽

Pratima Sinha ◽

Shun Takaku ◽

...

Keyword(s):

T Cells ◽

Tumor Immunity ◽

Critical Role ◽

Nkt Cells ◽

Mouse Tumor ◽

Type I ◽

Type Ii ◽

Tumor Models ◽

Down Regulation ◽

Mouse Tumor Models

The importance of immunoregulatory T cells has become increasingly apparent. Both CD4+CD25+ T cells and CD1d-restricted NKT cells have been reported to down-regulate tumor immunity in mouse tumor models. However, the relative roles of both T cell populations have rarely been clearly distinguished in the same tumor models. In addition, CD1d-restricted NKT cells have been reported to play a critical role not only in the down-regulation of tumor immunity but also in the promotion of the immunity. However, the explanation for these apparently opposite roles in different tumor models remains unclear. We show that in four mouse tumor models in which CD1d-restricted NKT cells play a role in suppression of tumor immunity, depletion of CD4+CD25+ T cells did not induce enhancement of immunosurveillance. Surprisingly, among the two subpopulations of CD1d-restricted NKT cells, Vα14Jα18+ (type I) and Vα14Jα18− (type II) NKT cells, type I NKT cells were not necessary for the immune suppression. These unexpected results may now resolve the paradox in the role of CD1d-restricted NKT cells in the regulation of tumor immunity, in that type II NKT cells may be sufficient for negative regulation, whereas protection has been found to be mediated by α-galactosylceramide–responsive type I NKT cells.

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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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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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