Thromb Haemost 2005; 94(03): 593-598
DOI: 10.1160/TH05-03-0208
Platelets and Blood Cells
Schattauer GmbH

Stereoselective inhibition of human platelet aggregation by R-138727, the active metabolite of CS-747 (Prasugrel, LY640315), a novel P2Y12 receptor inhibitor

Michihiro Hasegawa
1   Pharmacology and Molecular Biology Research Laboratories, Sankyo Co., Ltd., Shinagawa-ku, Tokyo, Japan
,
Atsuhiro Sugidachi
1   Pharmacology and Molecular Biology Research Laboratories, Sankyo Co., Ltd., Shinagawa-ku, Tokyo, Japan
,
Taketoshi Ogawa
1   Pharmacology and Molecular Biology Research Laboratories, Sankyo Co., Ltd., Shinagawa-ku, Tokyo, Japan
,
Takashi Isobe
1   Pharmacology and Molecular Biology Research Laboratories, Sankyo Co., Ltd., Shinagawa-ku, Tokyo, Japan
,
Joseph A. Jakubowski
2   BioMolecular Pharmacology, Eli Lilly and Company, Indianapolis, Indiana, USA
,
Fumitoshi Asai
1   Pharmacology and Molecular Biology Research Laboratories, Sankyo Co., Ltd., Shinagawa-ku, Tokyo, Japan
› Author Affiliations
Further Information

Publication History

Received: 29 March 2005

Accepted after major revision: 01 July 2005

Publication Date:
07 December 2017 (online)

Preview

Summary

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 P2Y12 ADP receptor. R-138727 is composed of 4 stereoisomers, (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.