title: Stereoselective inhibition of human platelet aggregation by R-138727, the active metabolite of CS-747 (prasugrel, LY640315), a novel P2Y12 receptor inhibitor.
abstract: CS-747 (Prasugrel, LY640315) is a thienopyridine antiplatelet prodrug that is metabolized to the thiol-containing active metabolite R-138727,which binds to and irreversibly inhibits the platelet P2Y12ADP receptor. R-138727 is composed of 4 stereo-isomers, (R, S)-, (R, R)-, (S, S)-, and (S, R)-isomers (the first letter for the configuration of a chiral center at the sulfur-bearing position and the second for that at the benzylic position). In the present study, we determined the stereoselectivity of P2Y12 antagonist effects by assessing the antagonism of the [3H]-2-MeS-ADP that binds to human P2Y12 receptors expressed in Chinese hamster ovary cells as an affinity assay, and by the inhibition of ADP-induced aggregation of washed human platelets as a functional assay. R-138727 and its 2 components, R-99224, a mixture of (R, S)- and (S, R)-isomers and R-100364, a mixture of (R, R)- and (S, S)-isomers, inhibited [3H]-2-MeS-ADP binding and platelet aggregation. The rank order of potency of these compounds were identical in both assays: R-99224>R-138727>> R-100364. Inhibition of ADP-induced platelet aggregation by R-138727 and R-99224 was concentration- and time-related. In experiments using the 4 single stereo-isomers, all isomers inhibited ADP-induced platelet aggregation, but the (R, S)-isomer was found to be the most potent, followed by the (R, R)-isomer. These in vitro studies indicate that R- 138727 is an effective antagonist of P2Y12 and potent inhibitor of ADP-induced platelet aggregation, and that these antiplatelet activities of R-138727 are largely dependent on its (R, S)-isomer. This suggests that the (R)-configuration of the reactive thiol group of the active metabolite of CS-747 is critical for P2Y12 and platelet inhibitory activities.
authors.affiliation: Pharmacology and Molecular Biology Research Laboratories, Sankyo Co., Ltd., Shinagawa-ku, Tokyo, Japan.
authors.forename: Michihiro
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Sugidachi
authors.forename: Taketoshi
authors.initials: T
authors.lastname: Ogawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Isobe
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Jakubowski
authors.forename: Fumitoshi
authors.initials: F
authors.lastname: Asai
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D001792:Blood Platelets / Q000187:drug effects*; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D003521:Cyclopropanes / Q000737:chemistry / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008565:Membrane Proteins / Q000037:antagonists & inhibitors*; D010879:Piperazines / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D010880:Piperidines / Q000737:chemistry / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D000068799:Prasugrel Hydrochloride; D011355:Prodrugs / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D058919:Purinergic P2 Receptor Antagonists; D058925:Receptors, Purinergic P2Y12; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D013876:Thiophenes / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D013997:Time Factors; D014162:Transfection
chemical_list: D003521:Cyclopropanes; D008565:Membrane Proteins; C548576:P2RY12 protein, human; D010879:Piperazines; D010880:Piperidines; D010975:Platelet Aggregation Inhibitors; D011355:Prodrugs; D058919:Purinergic P2 Receptor Antagonists; C510685:R-138727; C426068:R-99224; D058925:Receptors, Purinergic P2Y12; D013876:Thiophenes; D000068799:Prasugrel Hydrochloride