Figure 1: Ivacaftor is extensively metabolized in humans to less Figure 2: CFTR potentiation of D9- and D18-ivacaftor equal to ivacaftor2 active metabolites1

Figure 3: Human crossover study for D9- and D18-ivacaftor Figure 4: CTP-656 single ascending dose study

Figure 5: CTP-656 reduces metabolite exposure compared to Kalydeco®

Pharmacokinetic Studies of Deuterated Isotopologs of Ivacaftor in Preclinical Models and Healthy Volunteers

www.concertpharma.com Lexington, MA 02421

Copyright © 2012 Concert Pharmaceuticals, Inc. All rights reserved.

Scott L. Harbeson; Sophia Nguyen; Gary Bridson; Christopher L. Brummel; Vinita Uttamsingh; Lijun Wu; Adam J. Morgan; Ara M. Aslanian; Virginia Braman; Lana Pilja

ivacaftor equal to ivacaftor2

Models and DCE

Platform®

NH

O

NH

O

OH

NH

O

NH

O

OH

OH

NH

O

NH

O

OH

CO2HCYP3A4/3A5 CYP3A4/3A5

Ivacaftor AUC = 1

EC50 = 0.236 µM

M1 AUC = 6X

EC50 = 1.2 µM

M6 AUC = 2X

EC50 ≥ 13.5 µM 0 .8 4 2 0 1 0 00

1 0

2 0

3 0

[P o te n t ia to r ] (µ M )

Pe

ak

Isc

( µA

/cm

2)

i v a c a f t o r

D 9 - iv a c a f to r ( C T P -6 5 6 )

D 1 8 - iv a c a f t o r

M e a n + /- S D ; N = 6

-1 2 -1 1 -1 0 -9 -8 -7 -60 .0

0 .5

1 .0

1 .5

2 .0

2 .5

L o g C o m p o u n d [M ]

Ab

so

lute

Va

lue

∆I s

c

i v a c a f t o r

D 9 - iv a c a f to r (C T P -6 5 6 )

D 1 8 - iv a c a f t o r

Ussing chamber voltage-clamp FRT cells expressing G551D CFTR

Ussing chamber voltage-clamp F508del homozygous HBE

CTP-656 75 mg

CTP-656 150 mg

Kalydeco 150 mg

CTP-656 300 mg

PK Parameter Mean (CV%)

Tmax (hr)a

5.00 (5.00-12.00)

5.00 (5.00-10.00)

5.00 (3.00-10.00)

5.00 (5.00-10.00)

Cmax (ng/mL)

838 (22)

2,212 (26)

1,101 (46)

4,968 (23)

C24hr (ng/mL)

270 (36)

712 (40)

169 (38)

1,540 (39)

AUC0-inf (ng*hr/mL)

16,581 (31)

44,916 (36)

12,925 (32)

105,179 (34)

T1/2 (hr) 14.1 (17)

15.0 (21)

11.2 (16)

17.3 (14)

CL/F (L/hr) 4.9 (29)

3.8 (44)

13.3 (49)

3.2 (36)

NH

O

NH

O

OH

CD3

CD3CD3

NH

O

NH

O

OH

CD2

CD3CD3

OH

NH

O

NH

O

OH

CO2H

CD3CD3

NH

O

NH

O

OH

CO2H

NH

O

NH

O

OH

OH

NH

O

NH

O

OH

CTP-656 D-M1 D-M6 Ivacaftor M1 M6

Copyright © 2012 Concert Pharmaceuticals, Inc. All rights reserved.

Introduction • Deuterium can positively impact the metabolic

properties of a drug while preserving the intrinsic pharmacology

• Ivacaftor (Kalydeco) is extensively metabolized in humans to less active metabolites (Fig. 1)

• Ivacaftor was deuterated to assess the impact on metabolism and PK

• Two isotopologs, D9- and D18-ivacaftor (Fig. 2), were prepared and tested preclinically and clinically

• Both isotopologs had reduced metabolism in preclinical tests (data not shown)

• A human crossover study was conducted to identify the development candidate (Fig. 3)

• CTP-656 was selected for further clinical development

Methods • D9- and D18-ivacaftor were prepared in a site-selective

manner with high deuterium isotopic purity • In vitro CFTR potentiation was assessed in Ussing

chamber assays in FRT cells (G551D) or F508del homozygous HBE cells (Fig. 2)

• A crossover isotopolog selection study (dosed as aque-ous suspension in fasted state) was conducted (Fig. 3)

• A single ascending dose study was conducted under fed (high fat breakfast) conditions. The study included a crossover of Kalydeco (150 mg tablet) and CTP-656 (150 mg aqueous suspension) (Fig. 4)

• Quantitative metabolite profiles for CTP-656 and Kalydeco were generated using LC-MS/MS; metabolite standards were utilized (Fig. 5)

Results and Discussion • D9-, D18-ivacaftor and ivacaftor provided equivalent in

vitro CFTR potentiation (Fig. 2) • D9-ivacaftor showed a superior PK profile compared to

D18-ivacaftor; D9-ivacaftor (CTP-656) was selected for further evaluation (Fig. 3)

• PK profile for 150 mg CTP-656 was superior to Kalydeco 150 mg; CTP-656 demonstrated a linear dose-exposure relationship (Fig. 4)

• Exposure to less active metabolites was substantially lower for CTP-656 compared to Kalydeco (Fig. 5)

• Treatment-related adverse events were mild in severity with no apparent differences between CTP-656 and Kalydeco

1 Area under the curve (AUC) reported at steady state in healthy volunteers: normalized to ivacaftor AUC = 1. EC50 values reported for Isc increase (Ussing assay) in G551D/F508del HBE cells (NDA 203-188) 2 Peak current potentiated by sequential additions of test article. Experiments performed at ChanTest

0 1 2 2 40

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0

2 5 0 0

3 0 0 0

T im e (h r)

Me

an

(±

SE

M)

Pla

sm

a C

on

ce

ntr

ati

on

(n

g/m

L)

C T P -6 5 6

D 8 -M 1

D 6 -M 6

C T P -6 5 6 (1 5 0 m g s u s p e n s io n , P O )

0 1 2 2 40

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0

2 5 0 0

3 0 0 0

T im e (h r)

Me

an

(±

SE

M)

Pla

sm

a C

on

ce

ntr

ati

on

(n

g/m

L)

Iv a c a fto r

M 1

M 6

K a ly d e c o (1 5 0 m g ta b le t , P O )

CTP-656 PK Parameters: Parent/Metabolite Ratios AUC0-24hr Cmax C24hr

CTP-656/D-M1 2.0 2.1 2.2 CTP-656/D-M6 4.0 4.3 2.5

Ivacaftor PK Parameters: Parent/Metabolite Ratios AUC0-24hr Cmax C24hr

Ivacaftor/M1 0.58 0.54 0.55 Ivacaftor/M6 1.5 1.4 0.97

aMedian (Range) 0 8 1 6 2 40

2 0 0 0

4 0 0 0

6 0 0 0

8 0 0 0

T im e (h r)

Me

an

(±

SE

M)

Pla

sm

a C

on

ce

ntr

ati

on

(n

g/m

L)

C T P -6 5 6 _ 7 5 m g

C T P -6 5 6 _ 1 5 0 m g

C T P -6 5 6 _ 3 0 0 m g

Iv a c a fto r_ 1 5 0 m g

150 mg CTP-656

150 mg Kalydeco

Day 1 75 mg

CTP-656 300 mg CTP-656

N=10 7 day washout

Day 8

150 mg Kalydeco

150 mg CTP-656

Day 15

N=9 N=9

N=9

Day 22

7 day washout

7 day washout

NH

O

NH

O

OH

CD3

D3CCD3

D9-ivacaftorCTP-656

NH

O

NH

O

OH

CD3

D3CCD3

CD3D3CCD3

D18-ivacaftor

25 mg D-9

25 mg D-18

Day 1 25 mg D-18

25 mg D-9

Day 8

N=3

N=3

7 day washout

N=3

N=3

8 1 6 2 40

1 0 0

2 0 0

3 0 0

T im e (h r)

Me

an

(±

SE

M)

Pla

sm

a C

on

ce

ntr

ati

on

(n

g/m

L)

D 9 - iv a c a fto r

D 1 8 -iv a c a fto r

D9-ivacaftor D18-ivacaftor

PK Parameter Mean (CV%)

Tmax (hr)a 3.0 (2.0-4.0)

2.5

(2.0-5.0)

Cmax (ng/mL) 270 (24)

233 (18)

C24hr (ng/mL) 52.6 (28)

42.3 (16)

AUC0-inf (ng*hr/mL) 3,812 (26)

3,196 (15)

#29

aMedian (Range)