Preclinical Metabolism and Pharmacokinetics of SB1317 (TG02), a Potent CDK/JAK2/FLT3 Inhibitor

Mohammed Khalid Pasha, Ramesh Jayaraman, Venkatesh Pilla Reddy, Pauline Yeo, Evelyn Goh; Anthony Williams, Kee Chuan Goh, Ethirajulu Kantharaj

Abstract

SB1317 (TG02) is a novel small molecule potent CDK/JAK2/FLT3 inhibitor. To evaluate full potential of this development candidate, we conducted drug metabolism and pharmacokinetic studies of this novel anti-cancer agent. SB1317 was soluble, highly permeable in Caco-2 cells, and showed > 99% binding to plasma from mice, dog and humans. It was metabolically stable in human and dog liver microsomes relative to mouse and rat. SB1317 was mainly metabolized by CYP3A4 and CY1A2 in vitro. SB1317 did not inhibit any of the major human CYPs in vitro except CYP2D6 (IC50=1 μM). SB1317 did not significantly induce CYP1A and CYP3A4 in human hepatocytes in vitro. The metabolic profiles in liver microsomes from preclinical species were qualitatively similar to humans. In pharmacokinetic studies SB1317 showed moderate to high systemic clearance (relative to liver blood flow), high volume of distribution ( > 0.6 L/kg), oral bioavailability of 24%, ∼ 4 and 37% in mice, rats and dogs, respectively; and extensive tissue distribution in mice. The favorable ADME of SB1317 supported its preclinical development as an oral drug candidate.

Keywords: ADME, CYP450, metabolism, pharmacokinetics, SB1317/TG02, Cyclin dependent kinases, CDK/JAK2/FLT3, CDK inhibitors, Rat liver microsomes