PMID: 18578472

Authors:

Cox CD, Coleman PJ, Breslin MJ, Whitman DB, Garbaccio RM, Fraley ME, Buser CA, Walsh ES, Hamilton K, Schaber MD, Lobell RB, Tao W, Davide JP, Diehl RE, Abrams MT, South VJ, Huber HE, Torrent M, Prueksaritanont T, Li C, Slaughter DE, Mahan E, Fernandez-Metzler C, Yan Y, Kuo LC, Kohl NE, Hartman GD

Title:

Kinesin Spindle Protein (KSP) Inhibitors. 9. Discovery of (2S)-4-(2,5-Difluorophenyl)-N-[(3R,4S)-3-fluoro-1-methylpiperidin-4-yl]-2- (hydroxymethyl)-N-methyl-2-phenyl-2,5-dihydro-1H-pyrrole-1-carboxamide (MK-0731) for the Treatment of Taxane-Refractory Cancer.

Journal:

J Med Chem. 2008 Jun 25;.

Abstract:

Inhibition of kinesin spindle protein (KSP) is a novel mechanism for treatment of cancer with the potential to overcome limitations associated with currently employed cytotoxic agents. Herein, we describe a C2-hydroxymethyl dihydropyrrole KSP inhibitor ( 11) that circumvents hERG channel binding and poor in vivo potency, issues that limited earlier compounds from our program. However, introduction of the C2-hydroxymethyl group caused 11 to be a substrate for cellular efflux by P-glycoprotein (Pgp). Utilizing knowledge garnered from previous KSP inhibitors, we found that beta-fluorination modulated the p K a of the piperidine nitrogen and reduced Pgp efflux, but the resulting compound ( 14) generated a toxic metabolite in vivo. Incorporation of fluorine in a strategic, metabolically benign position by synthesis of an N-methyl-3-fluoro-4-(aminomethyl)piperidine urea led to compound 30 that has an optimal in vitro and metabolic profile. Compound 30 (MK-0731) was recently studied in a phase I clinical trial in patients with taxane-refractory solid tumors.