title: Nonclinical pharmacokinetics and metabolism of EPZ-5676, a novel DOT1L histone methyltransferase inhibitor.
abstract: (2R,3R,4S,5R)-2-(6-Amino-9H-purin-9-yl)-5-((((1r,3S)-3-(2-(5-(tert-butyl)-1H-benzo[d]imidazol-2-yl)ethyl)cyclobutyl)(isopropyl)amino)methyl)tetrahydrofuran-3,4-diol (EPZ-5676) is a novel DOT1L histone methyltransferase inhibitor currently in clinical development for the treatment of MLL-rearranged leukemias. This report describes the preclinical pharmacokinetics and metabolism of EPZ-5676, an aminonucleoside analog with exquisite target potency and selectivity that has shown robust and durable tumor growth inhibition in preclinical models. The in vivo pharmacokinetics in mouse, rat and dog were characterized following i.v. and p.o. administration; EPZ-5676 had moderate to high clearance, low oral bioavailability with a steady-state volume of distribution 2-3 fold higher than total body water. EPZ-5676 showed biexponential kinetics following i.v. administration, giving rise to a terminal elimination half-life (t1/2 ) of 1.1, 3.7 and 13.6 h in mouse, rat and dog, respectively. The corresponding in vitro ADME parameters were also studied and utilized for in vitro-in vivo extrapolation purposes. There was good agreement between the microsomal clearance and the in vivo clearance implicating hepatic oxidative metabolism as the predominant elimination route in preclinical species. Furthermore, low renal clearance was observed in mouse, approximating to fu -corrected glomerular filtration rate (GFR) and thus passive glomerular filtration. The metabolic pathways across species were studied in liver microsomes in which EPZ-5676 was metabolized to three monohydroxylated metabolites (M1, M3 and M5), one N-dealkylated product (M4) as well as an N-oxide (M6).
authors.affiliation: Epizyme Inc., 400 Technology Square, Cambridge, MA, USA.
authors.forename: Aravind
authors.initials: A
authors.lastname: Basavapathruni
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Olhava
authors.forename: Scott R
authors.initials: SR
authors.lastname: Daigle
authors.forename: Carly A
authors.initials: CA
authors.lastname: Therkelsen
authors.forename: Lei
authors.initials: L
authors.lastname: Jin
authors.forename: P Ann
authors.initials: PA
authors.lastname: Boriack-Sjodin
authors.forename: Christina J
authors.initials: CJ
authors.lastname: Allain
authors.forename: Christine R
authors.initials: CR
authors.lastname: Klaus
authors.forename: Alejandra
authors.initials: A
authors.lastname: Raimondi
authors.forename: Margaret Porter
authors.initials: MP
authors.lastname: Scott
authors.forename: Angelos
authors.initials: A
authors.lastname: Dovletoglou
authors.forename: Victoria M
authors.initials: VM
authors.lastname: Richon
authors.forename: Roy M
authors.initials: RM
authors.lastname: Pollock
authors.forename: Robert A
authors.initials: RA
authors.lastname: Copeland
authors.forename: Mikel P
authors.initials: MP
authors.lastname: Moyer
authors.forename: Richard
authors.initials: R
authors.lastname: Chesworth
authors.forename: Paul G
authors.initials: PG
authors.lastname: Pearson
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Waters
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000097:blood / Q000493:pharmacokinetics*; D001562:Benzimidazoles / Q000097:blood / Q000493:pharmacokinetics*; D001798:Blood Proteins / Q000378:metabolism; D004285:Dogs; D022781:Hepatocytes / Q000378:metabolism; D011495:Histone-Lysine N-Methyltransferase / Q000037:antagonists & inhibitors*; D061985:Madin Darby Canine Kidney Cells; D008297:Male; D008780:Methyltransferases / Q000037:antagonists & inhibitors*; D051379:Mice; D008862:Microsomes, Liver / Q000378:metabolism; D010539:Permeability; D017207:Rats, Sprague-Dawley
chemical_list: D000970:Antineoplastic Agents; D001562:Benzimidazoles; D001798:Blood Proteins; C583893:EPZ-5676; C481527:Dot1l protein, mouse; D008780:Methyltransferases; C583894:DOT1L protein, rat; D011495:Histone-Lysine N-Methyltransferase
keywords: MLL-rearranged leukemia; in vitro-in vivo extrapolation; metabolite identification; nonclinical pharmacokinetics