A Novel Agonist Antibody (INCAGN01876) That Targets the Costimulatory Receptor GITR

References 1. Schaer DA, et al. Curr Opin Immunol. 2012;24:217–224.2. Clouthier DL, et al. Cytokine Growth Factor Rev. 2014;25:91–106.3. Smith CA, et al. Cell. 1994;76:959–962.4. Allan SE, et al. Int Immunol. 2007;19:345–354.

5. Bianchini R, et al. Eur J Immunol. 2011;41:2269–2278.6. Chen DS, et al. Immunity. 2013;39:1–10.7. Leach DR, et al. Science. 1996;271:1734–1736.8. Bulliard Y, et al. J Exp Med. 2013;210:1685–1693.9. Turk MJ, et al. J Exp Med. 2004;200:771–782.

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Author DisclosuresAna Gonzalez, Ekaterina Breous, Mariana Manrique, David Savitsky, Jeremy Waight, Randi Gombos, Yuqi Liu, Shiwen Lin, Olivier Léger, Volker Seibert, Marc van Dijk, Robert Stein, Nicholas S. Wilson: Agenus Inc: Employment and Stock Ownership. Reid Huber, Peggy Scherle, Gregory Hollis: Incyte Corporation: Employment and Stock Ownership. Takemasa Tsuji, Taha Merghoub, Sadna Budhu, Roberta Zappasodi, Gerd Ritter, Jedd Wolchok: Nothing to disclose.

AcknowledgementsThe authors would like to thank Rebecca Woelfe for her assistance in preparing poster material and Joseph Connolly and Zhenyu Li for their help characterizing and producing INCAGN01876.Layout and printing support was provided by Evidence Scientific Solutions, Philadelphia, PA, funded by Incyte Corporation.

Conclusions

Abstract INCAGN01876 Binds to Primary Activated T Cells

GITR Functions as a T Cell Costimulatory Molecule

INCAGN01876 Activates FcγRIIIA Signaling in the Presence of Activated Regulatory T Cells

GITR is Selectively Expressed by IntratumoralRegulatory T Cells in Multiple Tumor Types

INCAGN01876 Mediates Antibody-Dependent Cellular Cytotoxicity (ADCC) by Natural Killer Cells

Activation of costimulatory receptors of the tumor necrosis factor receptor (TNFR) superfamily in T cells is considered a promisingalternative approach to potentiate anti-tumor immunity that may complement strategies focused on the blockade of co-inhibitorypathways such PD-1/PD-L1. Glucocorticoid-induced TNFR-related protein (GITR, CD357, or TNFRSF18) is an important T cellcostimulatory receptor that can potentiate T cell receptor (TCR) signaling during CD4+ and CD8+ T cell priming, effector celldifferentiation and memory T cell recall responses. In humans GITR expression is generally restricted to subsets of T cellsresponding to TCR stimulation, and is co-expressed with OX40. Like other TNFR family members, GITR costimulation can enhanceT cell responsiveness to suboptimal TCR signaling by activating the NFκB pathway, leading to enhanced cytokine responses andsurvival. GITR signaling in T cells may also promote resistance to the immune suppressive effects of regulatory T cells, therebyenhancing T cell responsiveness to weakly immunogenic tumor-associated antigens.

INCAGN01876 is a humanized IgG1 monoclonal antibody being developed for the treatment of advanced malignancies.INCAGN01876 potently binds to human and non-human primate GITR but does not cross-react with related TNFR family members.INCAGN01876 has been optimized to mediate receptor forward signaling under suboptimal TCR stimulatory conditions, leading toincreased production of TNFα and IFNγ by both CD4+ and CD8+ T cells. INCAGN01876 achieves this functionality by virtue of itsability to facilitate GITR clustering in TCR-stimulated T lymphocytes. In mouse preclinical tumor models, GITR was found to beselectively overexpressed by intratumoral regulatory T cells, a finding that was also observed in primary human tumor samples fromdiverse tumor types. In mouse models, this feature enabled a surrogate anti-GITR antibody to co-engage activating Fcγ receptorsexpressed by tumor-associated effector cells, and mediate the selective depletion of intratumoral regulatory T cells. Consistent withthis, INCAGN01876 was designed to co-engage activating Fcγ receptors and was shown to efficiently mediate immune effector cellmechanisms, including ADCC and ADCP. Taken together, the biophysical and functional attributes of INCAGN01876 make it ideallysuited for clinical development, both as a single agent and in combination with other immunomodulatory agents.

INCAGN01876 Enhances Primary T Cell Responses to Suboptimal TCR Stimulation

3220Ana Gonzalez,1 Ekaterina Breous,1,2 Mariana Manrique,1 David Savitsky,1 Jeremy Waight,1 Randi Gombos,1 Yuqi Liu,1 Shiwen Lin,1 Olivier Léger,1 Volker Seibert,1,2 Takemasa Tsuji,3Taha Merghoub,4 Sadna Budhu,4 Roberta Zappasodi,4 Gerd Ritter,3 Jedd Wolchok,3,4 Reid Huber,5 Peggy Scherle,5 Gregory Hollis,5 Marc van Dijk,1,2 Robert Stein,1 Nicholas S. Wilson1

1Agenus Inc., Lexington MA; 24-Antibody AG, Basel, Switzerland; 3The Ludwig Institute for Cancer Research, New York, NY; 4Memorial Sloan Kettering Cancer Center, New York, NY; 5Incyte Corporation, Wilmington, DE

Presented at theAmerican Association for Cancer Research Annual Meeting 2016New Orleans, LA, USA • April 16–20, 2016

INCAGN01876 Signaling in T Cells is Enhanced by TCR Costimulation

GITR Signaling in Cancer Immunotherapy

A. NFκB activation (relative light units [RLU]) by cross-linked INCAGN01876 or an isotype control antibody without TCR(anti-CD3 antibody) stimulation.

B. NFκB activation by cross-linked INCAGN01876 or an isotype control antibody with TCR stimulation.

A. INCAGN01876 does not bind to quiescent immune cells (flow cytometry).B. INCAGN01876 binds to stimulated (anti-CD3 antibody) T cells.C. Dose titration of INCAGN01876 binding to activated (anti-CD3) T cells.D. Affinity of INCAGN01876 by Bio-layer Interferometry.

A. Polyfunctional T cell response: Cross-linked INCAGN01876 enhances CD4+ and CD8+ T cell function in response toTCR stimulation (anti-CD3 antibody).

B. Dose-dependent increase in the frequency of CD8+ IFNγ+ T cells in response to INCAGN01876 together withsuboptimal TCR stimulation (anti-CD3 antibody).

C. Cytokines in the supernatant using human CD3+ cells stimulated with INCAGN01876 5 μg/mL with and withoutanti-CD3. Shown are the fold induction values (INCAGN01876 divided by the isotype control values) for the cytokinesdetected.

A. GITR-expressing target cells are incubated with FcγRIIIA-expressing natural killer (NK) cells and ADCC is measuredby calculating the percentage of target cell lysis.

B. GITR expressing target cell lysis by NK92-FcγRIIIA effector cells in the presence of a dose titration of INCAGN01876was assessed by photometric quantification of lactate dehydrogenase (LDH) released in the supernatant.

A. Schematic for the FcγRIIIA reporter based cell assay.B. A titration of INCAGN01876 on an IgG1 or IgG4 backbone was added to co-cultures of FcγRIIIA-expressing reporter

cells and GITR-overexpressing target cells. The delta response light units ([ΔRLU] isotype control values deducted) isshown.

C. GITR expression on activated Treg cells versus non-Treg cells by flow cytometry in two different donors. Delta meanfluorescence intensity (IgG1 isotype value deducted) is shown.

D. A titration of INCAGN01876 was added to co-cultures of FcγRIIIA-expressing reporter cells and activated human Tregor non-Treg cells. The ΔRLU is shown.

A. Representative histograms demonstratingGITR expression from tumor-associatedT effector cells or Treg cells.

B. GITR expression across various tumortypes.

C. Tabulated summary of GITR expression bytumor-associated T effector cells and Tregcells by indication.

Paradigm: GITR signaling in the context of TCR activation enhances effector T cell activation, cytokine production and survival1

Therapeutic hypothesis: INCAGN01876 (anti-GITR agonist antibody) enhances the responsiveness of T cells to weakly immunogenic tumor antigens and overcomes the suppressive activity of intratumoral regulatory T cells1

NO GITR STIMULUS

Teff CELLS

Treg CELLS

TUMOR CELLS

Foxp3+

Unstimulated

INCAGN01876 vs isotype control

Stimulated

GITR+ T cell (IHC)

Note: − = negative/no expression, + = weak expression, ++ = moderate expression, +++ = moderate-to-high expression, ++++ = high expression.CRC, colorectal carcinoma; Endo, endometrial; NSCLC, non-small cell lung carcinoma; RCC, renal cell carcinoma.

C

D

A B

A B C

GITR vs isotype control

CD4+ CD8+ B cells Other

Affinity of INCAGN01876

Human GITR

Ka (1/Ms) 6.8×105

Kd (1/s) 2.0×10−4

KD (nM) 0.21

A

B

Nor

mal

ized

Exp

ress

ion

LOG [INCAGN01876] (μg/mL)

100

50

0

−1−5 −3 10−4 −2 2

BA

Indication Samples (n) CD4+ T cells Treg cells

NSCLC 4 − +++

Endometrial 2 − ++++

Colorectal 3 − ++

Breast 2 − −

Ovarian 1 − ++

Renal 1 − +++

A B

C

INCAGN01876

GITR

FcγRIIIA

NFATpathway

GITR+ target cell, activated Tregor non-Treg (CD4+ T cells)FcRγIIIA NFAT reporter cell line

Luciferase

A B

C D

CD8+ and CD4+T cells

Treg cells

Endometrial Cancer

GITR vs istotype control

MHC-I

Naïve T Cell

GITR-L

EFFECTOR PHASE

TCR CD28 CD86 GITR GITR-L

SECONDARY PHASE

INITIALPRIMING

24–72 hours

ActivatedMature DC

GITR expressionupregulated

No GITRstimulus

GITRengagement

• Reduced T cell expansion/survival• Decreased cytokine production

• Enhanced effector T cell expansion/survival• Increased proinflammatory cytokine production

GITR LIGATION IMMUNOTHERAPY

anti-GITR antibodies

Foxp3+

Foxp3−

DENDRITIC CELL

TUMOR CELLS

IL-2 IFNγ TNFα IL-13

RL

UAntibody Concentration (μg/mL)

CD8+ T cells CD4+ T cells

Fre

qu

en

cy o

f

T C

ell

Po

pu

lati

on

s

6000

4000

2000

300

200

100

0100.1 1 100

RL

U

Antibody Concentration (μg/mL)

6000

4000

10

2000

00.1 1 100

INCAGN01876

IgG1 Isotype

25

20

15

10

0 42 6

5

0IFNγ+ TNFα+IFNγ+ TNFα+

INCAGN01876

without anti-CD3

INCAGN01876

with anti-CD3

8 10 60

Antibody Concentration (μg/mL)

% C

D8

+IF

Nγ

+T

cell

s

13

10

8

5

3

0

15

10

5

0

Fo

ld In

du

cti

on

30

INCAGN01876

IgG1 Isotype

IL-4IL-10

2

1

INCAGN01876 without anti-CD3

INCAGN01876 with anti-CD3

Isotype control

IgG1 Isotype

INCAGN01876

0.10.001 0.01 1

Antibody Concentration (μg/mL)

ΔR

LU

20,000

15,000

10,000

0

INCAGN01876 IgG4

INCAGN01876 IgG1

100.0001

5000

0.10.001 0.01 1

Antibody Concentration (μg/mL)

ΔR

LU

30,000

20,000

010

10,000

Treg cells

Non-Treg cells

Donor 1 Donor 2

ΔM

FI

20,000

16,000

10,000

0

4000

Treg cells

Teff

2000

0.000001 0.0001 0.01 1

Antibody Concentration (μg/mL)

Ta

rget

Ce

ll L

ys

is(%

)

30

20

10

0

IgG1 Isotype

INCAGN01876

100

12,000

10,000

8000

6000

4000

2000

0CRC RCC1 RCC2 RCC3 NSCLC Endo1 Endo2 Endo3

GIT

R (

nu

mb

er)

CD4+ T cells

Treg cells

CD8+ T cells

• INCAGN01876 selectively binds to GITR with an affinity of 0.21 nM and binds to activatedT cells in a dose-dependent manner

• INCAGN01876 functions as a potent activator of GITR signaling in T cell reporter assays,which is enhanced by TCR costimulation

• In the context of suboptimal TCR signaling, GITR binding by INCAGN01876 enhancesprimary T cell responsiveness (intracellular and secreted cytokines) only in the presenceof TCR stimulation (anti-CD3)

•

•

•

INCAGN01876 co-engages Fcγ receptors on activated regulatory T cells and mediatessignaling through activating FcγR up to 10 times more effectively than T effector cellsSamples from various tumor types demonstrate an enrichment in GITRhigh intratumoralTreg cells, that in the presence of INCAGN01876, are targets for ADCC/ADCPINCAGN01876 functions as effective agonist of the GITR pathway, and may have thepotential in patients to enhance T cell responsiveness to weakly immunogenic tumor-associated antigens, while attenuating the immune suppressive function of intratumoralpopulations of regulatory T cells. Taken together, these preclinical data support theclinical development of INCAGN01876

Cytotoxicgranules

ADCC

NK Cell

FcγRIIIAAntibody

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