Trillium Therapeutics : ASH 2015 Presentation

Slide 1

SIRPαFc, a CD47-Blocking Cancer Immunotherapeutic, Sensitizes Malignant B Cells to Macrophage-Mediated Destruction

Natasja Nielsen Viller1,2, Saman Maleki Vareki2,3, Karen Dodge1, Hui Chen1, Vivian Lee1, Vien Chai1, Xinli Pang1, Mark Wong1, Suzanne Trudel4, Rene Figueredo2,3, Macarena Pampillo2, James Koropatnick2,3, Penka S. Petrova1 and Robert A. Uger1

ASH 2015 Abstract #2191

1Trillium Therapeutics Inc., Toronto, ON, Canada, 2London Regional Cancer Program, London Health Sciences Centre, Lawson Health Research Institute, London, ON, Canada, 3Department of Oncology, University of Western Ontario, London, ON, Canada, 4Department of Medical Oncology and Hematology, Princess Margaret Cancer Centre, Toronto, ON, Canada

Introduction

• CD47 binds to SIRPα on the surface of macrophages and delivers a "do not eat" signal to suppress phagocytosis

• Tumor cells frequently overexpress CD47 and exploit this pathway to evade macrophage-mediated destruction

• Blocking CD47 using a soluble decoy receptor (SIRPαFc) has emerged as a promising strategy to neutralize the suppressive effects of CD47 and promote the eradication of tumor cells

• In this study we have examined the effects of SIRPαFc on malignant human B cells both in vitro and

in vivo

SIRPαFc Exhibits Strong Binding to a Panel of Human B Cell Tumors SIRPαFc is Efficacious in B Lymphoma Xenograft Models

M e d i a n F l u o r e s c e n c e

2 0 0 0 0

1 5 0 0 0

D i f f u s e L a r g e B C e l l L y m p h o m a

S I R P  F c

C o n t r o l F c S U D H L8

M e d i a n F l u o r e s c e n c e

2 5 0 0 0

2 0 0 0 0

N o n - D L B C L

B C e l l L y m p h o m a s

S I R P  F c

C o n t r o l F c

6 0 0 0

P r i m a r y B - A L L

S I R P  F c

Burkitt's Lymphoma

3

T u m o r V o l u m e ( m m )

1 5 0 0

1 0 0 0

D o s i n g W i n d o w

C o n t r o l F c S I R P  F c

1 0 0 0 0

5 0 0 0

E C 50 = 9 0 n M  1 6 5 n M

N U D U L 1

H T

T o l e d o

S U D H L 6

S U D H L 1 6

P f e i f f e r

S U D H L 4

1 5 0 0 0

1 0 0 0 0

5 0 0 0

E C 50 = 1 2 9 n M  1 0 2 n M

M M 1 s

R a j i

N a m a l w a

H 9 2 9

M e d i a n F l u o r e s c e n c e

4 0 0 0

2 0 0 0

E C 50

C o n t r o l F c

= 2 2 9  2 3 3 n M

(Raji, CD20high)

5 0 0

R i t u x i m a b

0

- 3 - 2 - 1 0 1 2 3 4 5

C o n c e n t r a t i o n ( L o g n M )

0

- 3 - 2 - 1 0 1 2 3 4 5

C o n c e n t r a t i o n ( L o g n M )

0

- 3 - 2 - 1 0 1 2 3 4 5

C o n c e n t r a t i o n ( L o g n M )

0

0 2 0 4 0 6 0

SIRPαFc: A Novel Biologic that Blocks the CD47 "Do Not Eat" Signal

SIRPαFc:

• Binds to CD47 with nanomolar affinity

• Disrupts the interaction of CD47 with cell surface SIRPα

• Enables macrophage-mediated killing of tumor cells in vitro

• Exhibits potent in vivo anti-tumor activity in B cell lymphoma xenograft models

• Is being developed as a therapy for lymphomas and other hematological malignancies

Binding of biotinylated SIRPαFc, followed by detection with streptavidin-PE, to a panel of B cell tumors by flow cytometry

2 0 0 0

D a y p o s t - E n g r a f t m e n t

SIRPαFc Enhances Macrophage-Mediated Phagocytosis of Malignant Human B cells

Human macrophages were generated from peripheral blood CD14+ monocytes. Macrophages were co-cultured with tumor

Burkitt's Lymphoma

cells +/- SIRPαFc or Control Fc for two hours

No treatment

Control Fc

SIRPαFc

(Namalwa, CD20low)

3

T u m o r V o l u m e ( m m )

1 5 0 0

1 0 0 0

D o s i n g W i n d o w

C o n t r o l F c S I R P  F c

R i t u x i m a b

P r i m a r y B - A L L

5 0 0

4 0 0

* * *

* * *

* * *

* * *

3 0 0

* * *

* * *

* * *

* * *

* * *

2 0 0

* * *

1 0 0

0

P a t i e n t # 1

D i f f u s e L a r g e B C e l l L y m p h o m a

N o n - D L B C L

B C e l l L y m p h o m a s

M M

P r i m a r y M M

3 0 0

* * *

8 0

8 0

4 0 0

* * *

* * *

* * *

6 0

6 0

3 0 0

* * *

2 0 0

* * *

* * *

4 0

4 0

2 0 0

* * *

* *

N S

1 0 0

* * *

* * *

2 0

* *

2 0

* * *

1 0 0

* * *

* * *

N S

*

N S

N S

N S

0

0

0

H T L y 1 P f e i f f e r N U D S U 4 S U 6

S U 8

S U 1 6 T o l e d o

N a m

R a j i

C 1 R

L y 5

M M 1 . s

8 2 2 6

H 9 2 9

U 2 6 6

0

P a t i e n t #

1

2

3

4

Phagocytosis Index = number of tumor cells engulfed per 100 macrophages. * p ≤ 0.05, ** p ≤ 0.01, *** p ≤ 0.001

Conclusions

• SIRPαFc binds strongly, and in a dose-dependent manner, to established cell lines and primary tumor cells from a panel of B cell malignancies, with an average effective half-maximal concentration of 150 nM

• SIRPαFc potently triggers macrophage-mediated phagocytosis of malignant B cells in vitro

• SIRPαFc treatment significantly reduces tumor burden in vivo in B lymphoma mouse xenograft models. Specifically, SIRPαFc significantly reduces Raji tumor cell growth, and completely ablates Namalwa tumor formation

• A Phase 1 dose escalation trial of SIRPαFc in subjects with advanced hematologic cancers will be opening in the near future

Disclosures. NNV: employment and research funding from TTI. SMV, RF, MP and JK: TTI research funding. KD, HC, VL, VC, XP, MW, PP and RU: TTI employment. ST: Novartis: Honoraria ; Oncoethix: Research Funding ; BMS: Honoraria ; TTI: Research Funding ; Celgene: Equity Ownership , Honoraria , Speakers Bureau ; Amgen: Honoraria , Speakers Bureau.

P h a g o c y t o s i s I n d e x

P h a g o c y t o s i s I n d e x

P h a g o c y t o s i s I n d e x

P h a g o c y t o s i s I n d e x

P h a g o c y t o s i s I n d e x

Hairless NOD.SCID (SHrN™) mice were implanted subcutaneously with tumor cells and dosed (IP) with mouse SIRPαFc (10 mg/kg), control Fc (6.67 mg/kg) or Rituximab (8 mg/kg) as indicated

5 0 0

0

0 2 0 4 0 6 0

D a y p o s t - E n g r a f t m e n t

2

3

4

5

6

7

8

9

1 0

Representative confocal microscopy images (all proteins at 1 μM). Primary B-ALL

tumor cells stained green, macrophages stained red.