In Vivo Activities of TP-2846: A Novel Tetracycline Antileukemia AgentXiao-Yi Xiao1, Cuixiang Sun1, Jian Zhou1, Noriaki Tatsuta1, Joseph Newman1, Douglas White2, Barbara Hibner2, Arijit Chakravarty2, and Jacques Dumas1

1Tetraphase Pharmaceuticals, Inc., Watertown, MA; 2Fractal Therapeutics, Inc., Cambridge, MA.

Poster # 3880

AACR (American Association for Cancer Research), March 29 – April 3, 2019, Atlanta, Georgia

Summary • TP-2846 displayed favorable pharmacokinetic profiles across multiple species. • TP-2846 demonstrated potent, dose-dependent in vivo efficacy in acute myeloid leukemia mouse xenograft models. In two studies presented, >50% tumor shrinkage was seen in all (or most) animals treated with TP-2846, while none of the comparator-treated animals achieved >50% tumor shrinkage.

• Pharmacokinetic/pharmacodynamic modeling indicates that TP-2846’s efficacy is driven primarily by AUC.

• These data sets, combined with other desirable in vitro, in vivo, and chemical-physical properties, support the continued development of TP-2846 as a new antileukemia agent.

References(i) E Mehrara, et al. Specific Growth Rate versus Doubling Time for Quantitative Characterization of Tumor

Growth Rate. Cancer Res. (2007), 67, 3970-3975.(ii) A Talkington, et al. Estimating Tumor Growth Rates. In Vivo. Bull. of Math. Biol. (2015), 77, 1934-1954.(iii) G Hather, et al. 2014. Growth Rate Analysis and Efficient Experimental Design for Tumor Xenograft

Studies. Cancer Inform (2014), 13(Suppl 4), 65–72.(iv) A Österroos, et al. Combination screening in vitro identifies synergistically acting KP372-1 and

cytarabine against acute myeloid leukemia. Biochem. Pharmacol. (2016), 118, 40-49.

Contact:Tetraphase Pharmaceuticals Medical Informationtetraphase@druginfo.com(833) 793-7282

MethodsPK Studies

PK studies were performed at WuXi AppTec or Charles River Laboratories. Animals (male CD-1 mice, Sprague Dawley rats, or cynomolgus monkeys) were dosed with TP-2846 by IP, IV, or PO administration. Blood samples were collected into heparin tubes and processed to plasma. Concentrations of TP-2846 in plasma were determined using a qualified LC-MS/MS method, and PK parameters were calculated using WinNonLin.

In Vivo Efficacy Studies

In vivo efficacy studies were performed at WuXi AppTec. Nude mice (n = 5-10, BALB/c or CD-17 SCID) were inoculated subcutaneously at the right flank with MV4-11 or HL-60 cells (10 x 106) in 0.2 mL of PBS with Matrigel (1:1) for tumor development. Treatments were started when average tumor size reached approximately 167-177 mm3 (7-11 days after inoculation, depending on tumor cell lines) by IP or IV administration of TP-2846, comparators, and vehicle (0.9% saline). Tumor size was measured 2 or 3 times weekly in two dimensions using a caliper, and tumor volume (V, mm3) was calculated by the following formula: V = 0.5 a x b2, where a and b are the long and short diameters of the tumor, respectively.

PK/PD Modeling

Tumor growth rate (Gr) was estimated for the analysis of efficacy in the HL-60 mouse xenograft model by the following equation: ln(TV)= Gr*t + ln(TV0), where TV = tumor volume, Gr = growth rate, t = time, TV0 = initial tumor volume, and ln = natural logarithm(i) (ii). Efficacy was expressed as the growth rate ratio between test groups and vehicle control group(iii). A 3-compartment model was used to fit the PK data. Maximum total plasma concentration (Cmax), cumulative area under the total plasma concentration-time curve (AUC), and time of free plasma concentration above IC50 (Free t>IC50) were calculated. The in vitro IC50 of TP-2846 in HL-60 cells is 189 ng/mL, and the protein binding in mouse plasma is about 57%. The correlations between in vivo efficacy and PK parameters (i.e., Cmax, AUC, and Free t>IC50) were used to determine which PK/PD driver has the best fit for the efficacy of TP-2846.

IntroductionTP-2846, a novel tetracycline derivative, has been identified as a highly potent antileukemia agent through high-throughput screening, medicinal chemistry studies, and in vitro profiling based on mechanistic rationales, as shown in posters #3857 and 4802. This poster presents data from in vivo evaluations of TP-2846.

Objectives • Study pharmacokinetics (PK) of TP-2846 in mice, rats, and monkeys • Evaluate in vivo efficacy of TP-2846 in various mouse AML models • Determine pharmacokinetic/pharmacodynamic (PK/PD) driver of TP-2846

Results

Species Route Dosage

TP-2846 PK Parameters

Cmax/0 Tmax T1/2 Tlast Vdss Cl AUC0-last AUC0-inf F% (mg/kg) (ng/mL) (h) (h) (h) (L/kg) (mL/min/kg) (ng·h/mL) (ng·h/mL) (%)

Mouse

IP 10 5340 0.50 6.81 24.0 5745 5944

IV

1 1142 6.15 16.0 8.56 23.7 628 704

3 5881 5.18 16.0 6.48 23.0 2016 2174

6 8518 6.92 16.0 9.80 23.8 3624 4205

Rat IV 5 7180 9.64 24.0 5.41 8.88 8180 9390

PO 5 4.39 0.67 9.41 24.0 21.1 21.0 0.3%

Monkey IV

1 734 9.97 24.0 3.17 4.04 3425 4128

2 1071 12.5 24.0 4.31 4.38 6141 8252

4 1835 15.7 24.0 4.73 3.77 12170 19179

Table 1. PK Parameters of TP-2846 in Mice, Rats, and Monkeys

Figure 1A. In Vivo Efficacy of TP-2846 by IP Administration in an MV4-11 Mouse (SCID) Xenograft Model (IC50 in MV4-11: TP-2846, 0.13 µM (avg.); tigecycline, 2.26 µM (avg.); cytarabine, 0.58 µM(iv). TGI = tumor growth inhibition)

pp

p

Note: dosing was suspended due to significant body weight loss on 2-9 days for 9 (out of 10) tigecycline treated animals, and on 1-5 days for 9 cytarabine treated animals during the course of the study, while only one animal from the TP-2846 group skipped one dose (the last one).

Figure 1B. Animal Body Weight Changes in Efficacy Study of TP-2846 by IP Administration in an MV4-11 Mouse (SCID) Xenograft Model

Model TP-2846 Cytarabine Tigecycline Vehicle

MV4-11 Mouse (SCID) Xenograft Model 9 0 0 0

HL-60 Mouse (BALB/c) Xenograft Model 10 0 0 0

Table 2. Number of Animals (Out of N=10) Achieving >50% Tumor Shrinkage in Efficacy Study of TP-2846 by IP Administration in MV4-11 and HL-60 Mouse Xenograft Models

Figure 2. In Vivo Efficacy of TP-2846 by IP Administration in an HL-60 Mouse (BALB/c) Xenograft Model (IC50 in HL-60: TP-2846, 0.22 µM (avg.); tigecycline, 5.70 µM (avg.); cytarabine, 0.26 µM)

pp

p

Note: in the cytarabine group, dosing was suspended due to significant body weight loss on 4 days for 2 (out of 10) animals, and one animal was euthanized after the 1st dosing cycle, while only one animal from the TP-2846 group skipped one dose (the last one).

Figure 3A. In Vivo Efficacy of TP-2846 by IV Administration in an HL-60 Mouse (BALB/c) Xenograft Model

Note: dosing was suspended due to significant body weight loss on one day for 2 (out of 5) cytarabine treated animals during the course of the study.

Figure 3B. Animal Body Weight Changes in Efficacy Study of TP-2846 by IV Administration in an HL-60 Mouse (BALB/c) Xenograft Model

Figure 4. TP-2846 PK/PD Modeling