Rod Stevens, PhD

執行役員医薬研究本部大正製薬（株）

June 5, 2015

Confidential & Privileged 1/24

The Discovery of Novel, Potent andOrally Active COX-2 Inhibitors:

‘Hit’ to Candidate

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O

OCOOH

O

O

COOH

OH

O

O

COOH

OOH

COOH

TXB2

TXA2

O

HO OH

COOH

PGD2, PGE2, PGF26-keto-PGF1

PHOSPHOLIPIDS

phospholipases

CYCLOOXYGENASE

PGI synthase TXA synthase

Arachidonic acid

PGG2

PGH2PGI2 (prostacyclin)

CYCLOOXYGENASE(PEROXIDASE SITE)

NSAIDSINHIBIT

OH

Site of Action of NSAIDs

X

Confidential & Privileged 3/24

NSAIDs – diverse chemical structures

Similar therapeutic actions• Antipyretic• Anti-inflammatory• Analgesic

Similar toxic effects• Ulceration• Renal toxicity

Beneficial and undesired effects attributedto single pharmacological action

Confidential & Privileged 4/24

NH

NO2O

H3CO2S

Breaking Science

Nimesulide

Marketed in Italy since 1985

NSAID anti-inflammatory activitybut better tolerated

Not COX inhibitor?Confidential & Privileged 5/24

Breaking Science

Needleman et al

In inflammatory conditions there is a marked increase inmass of COX enzyme

Stimulation of inflammatory cells with cytokine (e.g., IL-1)causes increase in PG synthesis capacity and COXenzyme levels

Blocked by dexamethasone, but basal COX not altered

Hypothesis, two COX enzymesConfidential & Privileged 6/24

COX-2 responsible for PGgeneration at inflammatory sites

CYTOKINES

COX-2INDUCED

PGsprostaglandins

COX-1CONSTITUTIVE

TXplatelets

PGI2gastric mucosa

PGF2kidney

INFLAMMATIONpain, swelling

SIDE EFFECTS

THERAPEUTIC EFFECTS

DEX X

NSAID XX

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NH

NO2O

H3CO2S

O2S

H3C

S

F

Breaking Science

COX-1 COX-2 Adj Arthritis GI ulcer

indomethacin 0.2 1.2 0.1 8

DuP 697 0.8 0.01 0.3 >600

NS 398 >10 0.01 4.7 >1000

IC50 (M) ED50 (mg/kg)

N

O

MeO

CO2H

Cl

indomethacin DuP 697 NS 398

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Normal

10mg/kg indomethacin

Ulceration

Confidential & Privileged 9/24

Competitor Landscape

Sulides

Tricyclics

NS 398

Merck, Ciba Geigy (Novartis), Bayer,Taisho, Fujisawa, Toyama, etc.

Searle (Pharmacia), Merck, GSK, Roche,JT, Sankyo, Fujisawa, Chugai, etc.

NN

CF3

O2S

H2NO

O2S

H3C

O

NH

NO2O

H3CO2S

Celebrex Vioxx

Confidential & Privileged 10/24

The Sulide class

– preliminary SAR around NS-398 was “tight”• limited space

Tricyclics

– highly competitive, limited patent space, difficult todifferentiate

• limited opportunity (→ License-in)

Screen ‘file’ for novel proprietary series

– high risk• initiate HTS

Strategy

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NH

Cl

S

Not well absorbed

“Hit” Profile

COX-1 COX-2

0.04 0.01

IC50 (M)

Pharmacology:cRFE: 42% inh @ 30 mg/kg, po

Pharmacokinetics:Cmax (rats): 0.15mg/ml @ 10 mg/kg, po

Confidential & Privileged 12/24

“Selectivity was improved,but oral absorption was poor”

NH

Cl

S

COX-2 (ratio COX-1)0.01 M (4)

NH

Cl

SO

NH

Cl

NHO

O

NH

Cl

NHO

O

COX-2 (ratio COX-1)0.03 M (10)

COX-2 (ratio COX-1)0.12 M (6)

COX-2 (ratio COX-1)0.1 M (35)

Improvement of Selectivity

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NH

Cl

NHO

O

• H-bond donors: 2

• mol. wt: 312.76

• cLogP: 4.0 (mLogP: 3.15)

• N + O = 4

• LogD: 3.6

• Solubility in PBS: 7 mg/ml

• (Caco-2: high permeability)

• H-bond donors: 1

• mol. wt: 357.80

• cLogP: 4.18 (mLogP: 2.85)

• N + O = 5

• logD: 1.5

• Solubility in PBS: 208 mg/ml

• (Caco-2: high permeability)

N

O O

OH

Cl

O

INDOMETHACIN

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NH

Cl

NHO

O

• H-bond donors: 2

• mol. wt: 357.80

• cLogP: 4.18 (mLogP: 2.85)

• N + O = 5

• logD: 1.7

• Solubility in PBS: >1000 mg/ml

Solubility Significantly Improved

NH

Cl

O

OHO

• H-bond donors: 2

• mol. wt: 312.76

• cLogP: 4.0 (mLogP: 3.15)

• N + O = 4

• LogD: 3.6

• Solubility in PBS: 7 mg/ml

• (Caco-2: high permeability)Confidential & Privileged 15/24

PK in rats at 10 mg/kg, po and in monkeys at 5 mg/kg, po

NH

Cl

NHO

O

NH

Cl

O

OHO

Absorption Improved

Confidential & Privileged 16/24

“Need to manifest selectivity for COX-2”

However ---

NH

Cl

O

OHO

COX-1 COX-2

0.79 0.4

IC50 (mM)

Confidential & Privileged 17/24

Need to develop synthetic route that,

Allows rapid SAR Regio-selective Readily available starting materials

Is scaleable

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NH

OY

Z

CO2Et

CO2Et

AcOH, AcONaNH

OY

Z

EtO2CCO2EtAcO

NH

O

CO2H1) Et3SiH, TFA2) KOH aq., EtOH, reflux

Y

Z

ref. E.Baciocchi et. al, J.Org.Chem., 58, 7610-7612(1993); D.R.Artis et.al, Can.J.Chem., 70, 1838-1842(1992)

Mn(OAc)3

YNC

CO2MeY

NH

CO2Me

SnBu3

XO

Z

YNH

CO2Me

O

Z

Pd(PPh3)4 (5%)Et3N (1eq.),100°C

n-Bu3SnH (1.1eq.),AIBN, CH3CN,100°C

ref. T.Fukuyama et.al, J.Am.Chem.Soc., 116, 3127-3128 (1994)

Known Synthetic Routes

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Retro-synthesis

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CO2R

NH2

X

Confidential & Privileged

Synthesis of Key Intermediate

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Indole Formation

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Indole Formation

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Candidate vs. celecoxib

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