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Discovery of a small molecule inhibitor
of Burton’s Tyrosine Kinase (BTK) for
autoimmune diseases
3rd International Conference and Exhibition on Clinical & Cellular Immunology
(Immunology Summit-2014) Sept 29-Oct 1 2014
Baltimore, USA
Loui Madakamutil, Ph.D
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Bruton’s Tyrosine Kinase - Btk
• Tec family kinase required for B-cell receptor
signaling in B cells and FCg receptor signaling
in myeloid cells
• Btk is not expressed in T cells
• Aberrant signaling through Btk implicated in
the pathogenesis of diffuse large B-cell
lymphoma, mantle cell lymphoma and chronic
B-cell leukemia
• Ibrutinib (PCI32765) recently approved for the
treatment of mantle cell lymphoma
Hendrix, Nat Chem Biol. 2011
Kuppers, Nature Rev. Cancer, 2005, 5, 251-62
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Efficacy and Commercial Opportunity
Efficacy: BTKi >> Belimumab and other
single axis biologics.
• BTKi has multiple nodes of intervention
in SLE pathology
BTKi in SLE
pathology
–
–
–
–
•
Immune-modulation
Prevent tissue damage
DMARD
Faster onset due to activity on multiple nodes
Small molecules compartmentalize to
organs unlike biologics
• Preclinical validation of BTKi for SLE
published* – PCI32765
Commercial Opportunity:
• Once daily pill >> biologic
nature reviews rheumatology, volume 6, 2010 pg547
Published Lead Series
• Published Btk inhibitor series were either covalent or high molecular
weight >500 Da and ligand efficiency ≤ 0.3
• Our question: Could a fragment based lead generation approach
successfully deliver a reversible BTK inhibitor lead
3
Fragment and Crystal structure based
discovery of BTK inhibitor
Compound 9
Mwt 318 Da
LogD 1.8
tPSA 123 Å
pBtk EC50 28 nM
Fragment Hit
Btk IC50 3.5 mM
LE 0.53
X-ray Co-crystal Structure – Btk kinase domain
P-Loop
Hinge
Floor
pocket
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BTK inhibitor: Pharmacology in vitro
pBTK
Rat WB
B cells
FceR
Mast cells
BAFF
B cells
FcgR
Macrophages
Compound 9
42
157
320
733
80
PCI-32765
Ibrutinib
3.1
30
380
300
10
Compound
Activity in several pathology nodes
•
•
•
•
Slide 5
BCR signaling
FceR signaling
BAFF signaling
FcgR signaling
m g /k g
0
10
500
3
10
3
1
V e h ic le
10
1000
1
20
1500
V e h ic le
30
2000
Ig G
40
0
6
P la s m a IL - 2 ( p g /m l)
50
U n t.
% C D 8 6 + B C e lls
Demonstrates selective activity to B cell
and spares T cells
Efficacy in CIA models
Mouse CIA
Rat CIA
D0
D0
D7
Immun.
D11
D12
D16
D19
D21
Immun.
Group
D21-24 D24
D34
D21 D22
Group
Treatment
Treatment
0 .6
8
N o rm a l
% In h ib itio n
 P a w v o lu m e
(m L , D 2 2 -D 1 1 )
0 .4
29%
43%
66%
94%
140%
0 .2
0 .0
T o t a l A r t h r it is S c o r e
V e h ic le
10%
3 m g /K g
6
1 0 m g /K g
3 0 m g /K g
4
2
m g /k g
0
-0 .2
N o rm . Ve h .
Slide 7
0 .1
0 .3
1
3
10
30
0
5
S tu d y D a y
10
Efficacy in anti-GBM nephritis model
Day 1
B35: 30 mg/rat i.v.
B.W. , plasma and urine sampling
@ Day 0,4, 6, 9, 12
Dosing start Day 4
T o t a l p r o t e in in U r in e ( m g )
Increased prominence of
membrane cells
(loss of Bowman's space)
200
N o rm a l
V e h ic l e
150
D e x 0 .1 m g /k g
C p d 9 , 3 0 m g /K g
C p d 9 , 1 0 m g /K g
100
C p d 9 , 3 m g /K g
50
0
0
5
10
D ays
Slide 8
15
Infiltration of
inflammatory cells
Summary and Conclusions
• Compound 9 was identified as a potent and selective inhibitor of BTK
• Compound 9 prevented downstream events mediated by BCR and FcR in
vitro. Further it also demonstrates the ability to block BAFF mediated B
cell survival
• Compound 9 shows no appreciable activity in T cell inhibitory activity
• Compound 9 shows potent and dose dependent inhibition of clinical
arthritis in CIA models
• Compound 9 shows unique activity in the IC mediated kidney damage
model
• BTK inhibitors are promising approach to treat diseases like RA and
nephritis mediated by IC
9
Acknowledgements
Takeda California, San Diego
Shonan Research Center, Japan
Shonan Research Center, Yokohama
Tokyo
Shonan
Enzyme Pharmacology
Ched Grimshaw
Petro Halkowycz
Structural Biology
Doug Dougan
BiChing Sang
Michael Klein
Computational Sciences
Dave Lawson
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Experimental Therapeutics
Loui Madakamutil
Jonathan Zalevsky
Keiko Ishigami
Ashleigh Keller
Yoshiki Nakamura
Myra Ng
Corey Wyrick
Cell Pharmacology
Ewan Taylor
Kim Peacock
Joe Russo
Pamela Farrell
Deepika Balakrishna
Analytical Chemistry
Catherine Pham
Haihong Wu
Lu Zeng
CMC
Chunrong Ma
David Provencal
Medicinal Chemistry
Christopher Smith
Mark Sabat
Phong Vu
Nick Scorah
Haixia Wang
DMPK
Ron Xu
Ron Chen
Heather Garcia
Melinda Manuel
Lisa Rahbaek
Jana Yu