FPT155: A first-in-class therapeutic CD80-Fc fusion ... - FPT155 oral... · FPT155: A first-in-class therapeutic CD80-Fc fusion protein that augments T cell co-stimulation Susannah

FPT155: A first-in-class therapeutic CD80-Fc fusion protein that augments T cell co-stimulationSusannah D Barbee, PhD

Five Prime Therapeutics, South San Francisco, CA

• I have the following financial relationships to disclose:

• I am an employee of Five Prime Therapeutics

• I am a stockholder in Five Prime Therapeutics

• I will not discuss off label use and/or investigational use in my presentation

Disclosure Information

© 2019 Five Prime Therapeutics, Inc. All Rights Reserved 2

3© 2019 Five Prime Therapeutics, Inc. All Rights Reserved

FPT155: First-In-Class CD80-Fc Fusion Protein Engineered to Activate T Cells Through Multiple Pathways

Normal T cell activation via CD80 FPT155 uses the binding interactions of CD80 to:

• Directly engage CD28 to enhance its co-stimulatory activity (without super agonism)

• Block CTLA-4 from competing for endogenous CD80, allowing CD28 signaling to prevail in T cell activation

Antigenpresenting cell

CD80 extracellular domain

T cell

(+) signal

TCRMHC

CD28CD80

Human IgG1 FcCD80 is a co-stimulatory molecule expressed on

antigen presenting cells

First in Human phase 1a/1b trial initiated in Nov 2018

• Flow cytometry-based assays indicate that FPT155 binds to cells via CD28 and CTLA-4 but not via

PD-L1

• FPT155 binds to primary T cells and in vitro-expanded T cells but not to hematopoietic subsets that

express only PD-L1 (e.g. monocytes)

FPT155 Binds to Cell-Surface CD28 and CTLA-4


CHO-CD28

Binding to cell lines that express a single ligand

CHO-CTLA-4 CHO-PD-L1

CD4+ T cells

CD8+ T cells

Monocytes

Binding to human

PBMC

1 0 -1 1 0 0 1 0 1 1 0 2

0

2 0

4 0

6 0

8 0

F P T 1 5 5 [n M ]

% b

ou

nd

by

FP

T1

55

1 0 -1 1 0 0 1 0 1 1 0 2 1 0 3 1 0 4

0

2 0

4 0

6 0

8 0

1 0 0

F P T 1 5 5 [n M ]

% b

ou

nd

by

FP

T1

55

1 0 -1 1 0 0 1 0 1 1 0 2 1 0 3 1 0 4

0

2 0

4 0

6 0

8 0

1 0 0

F P T 1 5 5 [n M ]

% b

ou

nd

by

FP

T1

55

1 0 2 1 0 3 1 0 4

0

2 0

4 0

6 0

8 0

1 0 0

F P T 1 5 5 [n M ]

FP

T b

ind

ing

(%

ma

x)

• 293-based “artificial APC” express an OKT3 scFv to provide TCR stimulation and/or a

truncated FcγRI to cluster FPT155 in the cellular synapse

• Activity observed with FPT155 requires TCR signal and Fc-mediated clustering

FPT155 Activity Requires Co-Presentation with TCR Stimulus


293-OKT3-CD64silent

293-OKT3

293-CD64silent

IL2 Production PD-1 expression

Naïve CD4+ T cells + 293 aAPC

CD28

293 aAPC

Human T cell

FPT155

TCR

.

CD64silentOKT3 scFv

1 0 1 1 0 2 1 0 3 1 0 4

0

2 0

4 0

6 0

8 0

1 0 0

D o n o r 7 4 - n a iv e 4 T

P D 1

F P T 1 5 5 [n M ]

% P

D-1

+

H E K 2 9 3 -O K T 3lo

-C D 6 4ta i l le s s

H E K 2 9 3 -O K T 3lo

H E K 2 9 3 -C D 6 4ta i l le s s

1 0 1 1 0 2 1 0 3 1 0 4

0

2 0

4 0

6 0

8 0

D o n o r 7 4 - n a iv e 4 T

P ro life ra t io n

F P T 1 5 5 [n M ]

% C

FS

Elo

H E K 2 9 3 -O K T 3lo

-C D 6 4ta i l le s s

H E K 2 9 3 -O K T 3lo

H E K 2 9 3 -C D 6 4ta i l le s s

• FPT155 potently co-stimulates the activation of MART-1 antigen-specific T cells in vitro

• The effect is sensitive to peptide concentration, indicating that TCR-induced signals are critical for activity

• Activity is observed at lower concentrations than are required to detect soluble binding, and lower than are

expected to saturate CTLA-4

• Absence of activity with Ipilimumab suggests that FPT155 may be efficacious when co-stimulation is limiting

FPT155 Co-Stimulates T Cells in the Context of Antigen-Specific TCR Stimulation when CD28 Ligands are Limiting


CD28

K562

Transduced human T cell

FPT155

HLA-A2

MART-1

TCR

.

CD64silent

0.3 ng/mL

1.1 ng/mL

3.3 ng/mL

10 ng/mL

MART-1 peptide titration 10 ng/mL MART-1 peptide

MART-1 TCR+ panT cells + K562 aAPC

Fc control

Fc control +10 μg/mL

Ipilimumab

FPT155

1 0 - 1 1 0 0 1 0 1 1 0 2

0 .0

0 .2

0 .4

0 .6

0 .8

1 0 n g /m L p e p tid e

F P T 1 5 5 o r F c c o n tro l [n M ]

IL2

[n

g/m

L]

F c c o n tro l + 1 0 u g /m L Ip i

F P T 1 5 5 + 1 0 u g /m L Ig G 1 c o n tro l

0

F c c o n tro l + 1 0 u g /m L Ig G 1 c o n tro l

IL2 production

1 0 - 1 1 0 0 1 0 1 1 0 2

0 .0

0 .2

0 .4

0 .6

IL2

F P T 1 5 5 [n M ]

IL2

[n

g/m

L]

1 0 n g /m L

3 .3 n g /m L

1 .1 n g /m L

0 .3 n g /m L

M A R T -1 p e p tid e

0

• The CD28 superagonist antibody TGN1412 induces spontaneous cytokine release by PBMC when

immobilized on plastic

• The cytokine profile matches that of clinical cytokine release syndrome

• FPT155 alone does not induce spontaneous cytokine release in this format

• Cytokines are produced when FPT155 is co-immobilized with anti-CD3, indicating that FPT155 is functionally

active in this assay format, but requires co-engagement with the TCR for T cell activation

FPT155 is Not a T Cell Superagonist


FPT155 alone

FPT155

+ anti-CD3

TGN1412 alone

n = 5

Each line represents an

individual donor

IL2IFNγ IL6 TNFα

0 0 .1 0 .3 1 3 1 0 3 0

0

2 0 0

4 0 0

6 0 0

8 0 0

P ro te in [g /w e ll]

IFN

[p

g/m

l]

0 0 .1 0 .3 1 3 1 0 3 0

0

4

8

1 2


IL2

[n

g/m

l]

0 0 .1 0 .3 1 3 1 0 3 0

0

2 0 0

4 0 0

6 0 0

8 0 0

1 0 0 0


IL6

[n

g/m

L]

0 0 .1 0 .3 1 3 1 0 3 0

0

1 0

2 0

3 0

4 0


TN

F

[n

g/m

l]

Spontaneous PBMC cytokine release in vitro

• mFPT155 exerts monotherapy anti-tumor activity in multiple tumor models including CT26, MC38,

EMT6, A20, and WEHI164‡

• Mice that reject tumors in response to mFPT155 are protected from subsequent re-challenge

• mFPT155 exhibits synergistic activity in combination with anti-PD-1 in the CT26 model

The Murine Surrogate mFPT155 Can Induce Complete Tumor Regression After a Single Dose at 0.2 mg/kg


0 5 1 0 1 5 2 0 2 5 3 0

0

4 0 0

8 0 0

1 2 0 0

1 6 0 0

2 0 0 0

2 4 0 0

T u m o r G ro w th

D a y s p o s t- in o c u la t io n

Tu

mo

r V

olu

me

(Me

an

mm

3

SD

)

0 0 2 1 0 1 3

0

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0

D a y 2 1

Tu

mo

r V

olu

me

(Me

an

mm

3

SD

)

**

N u m b e r o f tu m o r re g re s s io n s (o f 1 5 )

mIgG2a

mFPT155 0.1 mg/kg

mFPT155 0.2 mg/kg

mFPT155 0.6 mg/kg

mFPT155 0.9 mg/kg

CT26 tumor growth Day 21 tumor volume

Number of tumor regressions (of n = 15)

‡Data on file

• mFPT155 also has significant activity in other refractory

tumor models, including Renca and 4T1‡

• Activity in such tumor models suggests that FPT155

could have clinical activity in tumor types that respond

poorly to IO therapies

mFPT155 is Efficacious in Tumor Models Typically Refractory to IO Treatment


0 5 1 0 1 5 2 0

0

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0

2 5 0 0

D a y s p o s t- in o c u la tio n

0 5 1 0 1 5 2 0

0

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0

2 5 0 0


0 5 1 0 1 5 2 0

0

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0

2 5 0 0


Tu

mo

r V

olu

me

(m

m3)

0 5 1 0 1 5 2 0 2 5

0

2 0

4 0

6 0

8 0

1 0 0


Pe

rce

nt

su

rviv

al

B16-F10

tumor

growth

B16-F10

survival

mIgG2b control

mFPT155 (mIgG2a)

3 mg/kg

anti-CTLA4 (mIgG2b)

10 mg/kg

‡Data on file

0

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0

2 5 0 0

D a y 2 1

* * * *n s

* * * *

* * * *n s

0 5 1 0 1 5 2 0 2 5

0

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0

2 5 0 0

T u m o r G ro w th

D a y s p o s t- in o c u la t io n

Tu

mo

r V

olu

me

(Me

an

mm

3

SD

)

• CTLA-4 blockade via a Fc-silent antibody has minimal monotherapy activity against CT26

• Slight but non-significant loss of activity in combination suggests that mFPT155 has CTLA-4-

mediated function independent of neutralization

mFPT155 Retains the Majority of Its Activity in vivo Independent of Its Interactions with CTLA-4


anti-CTLA4-silent

mFPT155

mIgG2a 50 mg/kg

mFPT155 0.9 mg/kg

anti-CTLA-4-silent 50 mg/kg

Combination

CT26 tumor growth Day 21 tumor volume

• mFPT155 treatment promotes recruitment and subsequent infiltration of T cells

• The response is specific to effector T cells and is not observed for Treg

mFPT155 Promotes Effector T Cell Recruitment into Tumors


CD3 staining in CT26 tumors CD4 and CD8 staining in MC38 tumors

Control

mFPT155

skin

tumor

Adjacent normal

Tumor margin

Tumor core

n = 5 per group

CD4 CD8

Days post-treatment

0

2 5 0 0

5 0 0 0

7 5 0 0

IgG

2a

mF

PT

155

IgG

2a

mF

PT

155

11 15

0

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0

De

ns

ity

(#

/mm

2)

IgG

2a

mF

PT

155

IgG

2a

mF

PT

155

11 15

• mFPT155 preferentially induces effector T cell activation in the tumor as detectable by

transcriptomics and flow cytometry

• Effect is observed in peripheral blood only in tumor-bearing animals, indicating that mFPT155 does

not induce non-specific T cell activation at projected clinical dose levels

mFPT155 Induces T Cell Activation in Tumor-Bearing Animals at Projected Clinical Dose Levels


mIgG2a

mFPT155 0.1 mg/kg

mFPT155 0.3 mg/kg

mFPT155 0.9 mg/kg

mFPT155 10 mg/kg

mFPT155 50 mg/kg

Norm

aliz

ed m

RN

A

Tumor Whole blood Whole blood

CT26 tumor-bearing mice Naïve mice

Gzmb expression 11 days after mFPT155 administration

0 .1

1

1 0

1 0 0

* * *

0 .1

1

1 0

1 0 0

* *

0 .1

1

1 0

1 0 0

* ** **

• Trial initiated in Australia; expansion to other countries in Phase 1b

• A conservative MABEL approach was used to select starting dose for dose escalation

• We are currently evaluating combination strategies

Phase 1a/1b Clinical Trial to Evaluate FPT155 Monotherapy Activity


PHASE 1aDose Escalation

PHASE 1bExpansion at Chosen Dose

Any Solid Tumor

Basket of Solid Tumors

Exploratory Cohorts

Select Solid Tumor Cohorts

Initiated

November 2018

Study Objectives

• Safety

• Objective response

rate and duration

• Survival

• Baseline and

on-treatment

biopsies

Real-Time Safety Assessments

• Local lab tests labs include complete blood count, full chemistry panel, and CRP on D2 and weekly

in C1

Retrospective Analyses

• Tumor at baseline (archival)

• Evidence of tumor immunogenicity (IHC, RNA, DNA)

• Tumor pre-/on-treatment biopsies mandated in 1a exploratory cohorts

• Optional biopsy collection at progression

• Immune infiltration and activation (IHC, RNA)

• Peripheral blood pre-/on-treatment

• T cell phenotype (flow cytometry)

• Peripheral cytokines, including CRS signature

• Tumor mutation burden (ctDNA)

Biomarker Analyses to Monitor Safety, Efficacy, and MOA Endpoints


• FPT155 is a first-in-class CD80-Fc fusion protein engineered to activate T cells via

engagement of CD28 and CTLA-4

• FPT155 does not have TCR-independent superagonist activity in nonclinical studies

• The murine surrogate (mFPT155) has potent anti-tumor activity in multiple murine tumor

models, including models typically refractory to IO agents

• mFPT155 has synergistic combination activity with anti-PD1

• mFPT155 promotes a favorable tumor immune contexture characterized by effector T cell

infiltration and activation

• mFPT155 preferentially activates T cells in the tumor microenvironment vs periphery

• Five Prime initiated a Phase 1a/1b clinical trial in November 2018

Summary


16© 2019 Five Prime Therapeutics, Inc. All Rights Reserved

Acknowledgements

FPT155 Core Team

Jim Adair

Ago Ahene

Leslie Fok

Sharon Horton

Sandeep Inamdar

Marc Lopez

Monica Macal

Siddhartha Mitra

Danielle Pasqualone

Renuka Sivendran

Maike Schmidt

Hong Xiang

Shelly York

Five Prime Therapeutics Senior Management

Aron Knickerbocker

Bryan Irving

Helen Collins

Nallakkan Arvindan

Francis Sarena

David Smith

External

MART-1 TCR system: Steven Rosenberg, NCI

Patients and clinicians participating in the FPT155-001 trial

Documents

FPT155: A first-in-class therapeutic CD80-Fc fusion ... - FPT155 oral... · FPT155: A first-in-class therapeutic CD80-Fc fusion protein that augments T cell co-stimulation Susannah