GM-CSF is a Pro-Inflammatory Cytokine in Experimental Vasculitis of Medium and

Large Arteries

Ryu Watanabe, Hui Zhang, Toshihisa Maeda, Mitsuhiro Akiyama, Rohan Gandhi, John F. Paolini, Gerald J. Berry, Cornelia M. Weyand

Stanford University School of Medicine

Kiniksa Pharmaceuticals Corp

2019 ACR/ARHP Annual Meeting, Atlanta November 11

Disclosure

➢Study is funded by Kiniksa Pharmaceuticals Ltd

Granulocyte-macrophage colony-stimulating factor (GM-CSF)

➢Cellular sourcesT cells, B cells, macrophages, neutrophils, endothelial cells and fibroblasts

➢FunctionsDevelopment and maintenance of macrophagesNeutrophil activationAngiogenesis

Nat Rev Rheumatol. 2016;12:37-48.

Anti-GM-CSF receptor antibody as an immuno-regulatory agent

➢ Mavrilimumab (anti-GM-CSF receptor antibody) competes with GM-CSF for binding to the GM-CSF receptor α chain

➢ Therapeutic benefit in clinical trial of Rheumatoid arthritis (Burmester et al., Ann Rheum Dis 2013; 72: 1445-1452)

Giant cell arteritis (GCA)

➢ Medium/large vessel vasculitis

➢ Affects the elderly ( >50 years)

➢ Infiltration of CD4 T cells and macrophages;giant cell formationvascular remodeling

➢ High expression of GM-CSF mRNAin temporal arteries affected by GCA

Temporal arteritis

Weyand CM, et al. Clin Immunol. 2019

Ann Intern Med. 1994

GM-CSF functions as an amplifier of vascular inflammation

Hypothesis

Methods

➢GM-CSF expression- in tissue biopsies from patients with GCA- in vivo: human artery-SCID chimeric mice.

➢Blocking GM-CSF activityMavrilimumab, KPL-301; a monoclonal anti-GM-CSFreceptor antibody(300 μg given over one week in established vasculitis)

GM-CSF mRNA expression in temporal artery biopsies

GCA arteries

Non-inflamed arteries

GM-CSF

0

10

20

30

40

Rel

ativ

ee

x pre

ssio

n P<0.0001

GM-CSF-producing T cells in vasculitic lesions

GM-CSF

IntMed

Adv

50μM

CD3

GM-CSF-producing T cells are selectively recruited to the inflamed vessel wall

NSGmouse

GCA PBMCtransfer

Human artery engraftment

Vasculitis induction

Spleen Blood Artery0

10

20

30

% o

f G

M-C

SF+

CD

4+

T ce

lls P<0.001

P<0.05

* GM-CSF+ CD4+ T cells measured by intracellular cytokine stain

Can Mavrilimumab suppress vasculitogenic activity in vivo?

NSGmouse

GCA PBMCtransfer

Human artery engraftment

300 μg mavri/mouse

300 μg iso control/mouse

Vasculitis

Explanted arteryDay 22

Gene expressionIHC

FACS

Anti-GM-CSFR Ab reduces vessel wall inflammation

Anti-GM-CSFRα

No

. of

CD

3+

cells

/HP

F P<0.001

0

20

40

60

80

100

CD3

control IgG

100 μm

control IgG

Anti-GM-

CSFRα

Anti- GM-CSFR Ab suppresses vessel wall inflammation

* P<0.05, ** P<0.01, *** P<0.001A B C D E F G H I J K L

123456789

101112 0

1

2

3

4

A B C D E F G H I J K L

123456789

101112 0

1

2

3

4TCRIFNγIL-17IL-21

CD163IL-1IL-6

TNFαCCL5

CCL22VEGF

Endothelin 0

1

2

3

4

Control IgG aGM-CSFRαP value

*****ns*****ns

****

GM-CSF signaling promotes neoangiogenesisand intimal hyperplasia

(CD31/αSMA/DAPI)Control IgG Anti-GM-CSFRα

(CD31/αSMA/DAPI)

No

. of

mic

rove

ssel

s/H

PF

P<0.001

0

10

20

30

Inti

mal

th

ickn

ess

(μ

m)

P<0.001

0

50

100

150

Control IgGAnti-GM-CSFR

Summary

1. GM-CSF mRNA is abundant in GCA-affected arteries.

2. The major sources of GM-CSF in the inflamed artery are CD4 T cells.

3. GM-CSF promotes innate and adaptive immunity in the vessel wall lesionsand amplifies tissue vascularization and intimal hyperplasia.

4. Mavrilimumab, an anti-GM-CSF receptor antibody, is highly effective in suppressing vasculitis and the vasculitis-associated wall remodeling.

Acknowledgements

T Maeda, MD PhD

M Akiyama, MD PhD

H Zhang, MD PhD

CM Weyand. MD PhD JJ Goronzy, MD PhD

GJ Berry, MD

R Watanabe, MD PhD