Figure 1: Ivacaftor is extensively metabolized in humans to less Figure 2: CFTR potentiation of D9- and D18-ivacaftor equal to ivacaftor 2 active metabolites 1 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 DCE Platform ® N H O N H O OH N H O N H O OH OH N H O N H O OH CO 2 H CYP3A4/3A5 CYP3A4/3A5 Ivacaftor AUC = 1 EC 50 = 0.236 µM M1 AUC = 6X EC 50 = 1.2 µM M6 AUC = 2X EC 50 ≥ 13.5 µM 0.8 4 20 100 0 10 20 30 [Potentiator] ( µ M) Peak I sc ( µ A/cm 2 ) ivacaftor D9-ivacaftor (CTP-656) D18-ivacaftor Mean +/- SD; N=6 -12 -11 -10 -9 -8 -7 -6 0.0 0.5 1.0 1.5 2.0 2.5 Log Compound [M] Absolute Value ∆ I sc ivacaftor D9-ivacaftor (CTP-656) D18-ivacaftor 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%) T max (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) C max (ng/mL) 838 (22) 2,212 (26) 1,101 (46) 4,968 (23) C 24hr (ng/mL) 270 (36) 712 (40) 169 (38) 1,540 (39) AUC 0-inf (ng*hr/mL) 16,581 (31) 44,916 (36) 12,925 (32) 105,179 (34) T 1/2 (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) N H O N H O OH CD 3 CD 3 CD 3 N H O N H O OH CD 2 CD 3 CD 3 OH N H O N H O OH CO 2 H CD 3 CD 3 N H O N H O OH CO 2 H N H O N H O OH OH N H O N H O OH CTP-656 D-M1 D-M6 Ivacaftor M1 M6 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. EC 50 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 12 24 0 500 1000 1500 2000 2500 3000 Time (hr) Mean ( ± SEM) Plasma Concentration (ng/mL) CTP-656 D8-M1 D6-M6 CTP-656 (150 mg suspension, PO) 0 12 24 0 500 1000 1500 2000 2500 3000 Time (hr) Mean ( ± SEM) Plasma Concentration (ng/mL) Ivacaftor M1 M6 Kalydeco (150 mg tablet, PO) CTP-656 PK Parameters: Parent/Metabolite Ratios AUC 0-24hr C max C 24hr 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 AUC 0-24hr C max C 24hr Ivacaftor/M1 0.58 0.54 0.55 Ivacaftor/M6 1.5 1.4 0.97 a Median (Range) 0 8 16 24 0 2000 4000 6000 8000 Time (hr) Mean ( ± SEM) Plasma Concentration (ng/mL) CTP-656_75 mg CTP-656_150 mg CTP-656_300 mg Ivacaftor_150 mg 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 N H O N H O OH CD 3 D 3 C CD 3 D9-ivacaftor CTP-656 N H O N H O OH CD 3 D 3 C CD 3 CD 3 D 3 C CD 3 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 16 24 0 100 200 300 Time (hr) Mean ( ± SEM) Plasma Concentration (ng/mL) D9-ivacaftor D18-ivacaftor D9-ivacaftor D18-ivacaftor PK Parameter Mean (CV%) T max (hr) a 3.0 (2.0-4.0) 2.5 (2.0-5.0) C max (ng/mL) 270 (24) 233 (18) C 24hr (ng/mL) 52.6 (28) 42.3 (16) AUC 0-inf (ng*hr/mL) 3,812 (26) 3,196 (15) #29 a Median (Range)