Discovery of a small molecule inhibitor of Burton’s Tyrosine Kinase (BTK) for autoimmune diseases

Loui Madakamutil, Ph.D

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autoimmune diseases3rd International Conference and Exhibition on Clinical & Cellular Immunology (Immunology Summit-2014) Sept 29-Oct 1 2014Baltimore, USA

Bruton’s Tyrosine Kinase - Btk

• Tec family kinase required for B-cell receptor signaling in B cells and FCγ 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 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

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Hendrix, Nat Chem Biol. 2011Kuppers, Nature Rev. Cancer, 2005, 5, 251-62

Efficacy and Commercial Opportunity

BTKi in SLE

pathology

Efficacy: BTKi >> Belimumab and other

single axis biologics.

• BTKi has multiple nodes of intervention

in SLE pathology– Immune-modulation

– Prevent tissue damage

– DMARD

– Faster onset due to activity on multiple nodes– 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

N

N NN

NH2

OPh

N

HN

NH

N

N

OH

O

N

N

OHN

NH

O

N

N

O

O

NF

• Our question: Could a fragment based lead generation approach successfully deliver a reversible BTK inhibitor lead

3

NO

N HS

IbrutinibPharmacyclics

Irreversible

RN486 RocheMwt 592 Da

Btk Kd 0.3 nMLE 0.30

GDC0834 GileadMwt 596 Da

Btk IC50 6 nMLE 0.27

Fragment and Crystal structure based discovery of BTK inhibitor

Fragment Hit

Btk IC50 3.5 µMLE 0.53

X-ray Co-crystal Structure – Btk kinase domain

NN

NH2

NH2

O

N

NH

Mwt 318 DaLogD 1.8

tPSA 123 ÅpBtk EC50 28 nM

Compound 9

4

P-Loop

Floor pocket

Hinge

X-ray Co-crystal Structure – Btk kinase domain

BTK inhibitor: Pharmacology in vitro

Compound pBTKRat WBB cells

FceRMast cells

BAFFB cells

FcgRMacrophages

Compound 9 42 157 320 733 80

PCI-32765Ibrutinib

3.1 30 380 300 10Ibrutinib

Slide 5

Activity in several pathology nodes

• BCR signaling

• FcεR signaling

• BAFF signaling

• FcγR signaling

Demonstrates selective activity to B cell and spares T cells

ma IL-2 (pg/ml)

CD86+ B Cells

6

Plasm

IgG

Vehicle 1 3

10

Unt.

Vehicle 1 3

10

% C

Efficacy in CIA models

D22D0 D7 D11 D12

Immun. Group Treatment

D21D19D16

0.6

% Inhibition

D0 D21 D21-24 D24

Immun. Group Treatment

D34

8Normal

Vehicle

Rat CIA Mouse CIA

Slide 7

Norm. Veh. 0.1 0.3 1 3 10 30-0.2

0.0

0.2

0.4

mg/kg

10% 29% 43% 66% 94% 140%

Paw volume

(mL, D22-D11)

0 5 100

2

4

6

Vehicle

3 mg/Kg

10 mg/Kg

30 mg/Kg

Study Day

Total Arthritis Score

Efficacy in anti-GBM nephritis model

Day 1

B35: 30 µg/rat i.v.B.W. , plasma and urine sampling

@ Day 0,4, 6, 9, 12

Day 4Dosing start

200

mg)

Increased prominence of membrane cells (loss of Bowman's space)

Infiltration of inflammatory cells

Slide 8

0 5 10 150

50

100

150

Normal

Vehicle

Dex 0.1mg/kg

Cpd 9, 10 mg/Kg

Days

Total protein in Urine (m

Cpd 9, 30 mg/Kg

Cpd 9, 3 mg/Kg

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

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Acknowledgements

Takeda California, San Diego Shonan Research Center, YokohamaShonan Research Center, Japan

Tokyo

Shonan

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