title: Pharmacodynamic assessment of a novel P2Y12 receptor antagonist in Japanese patients with coronary artery disease undergoing elective percutaneous coronary intervention.
abstract: BACKGROUND
  Numerous reports have shown that prasugrel shows a rapid and consistent antiplatelet effect among European and US patients. Previous studies suggest that prasugrel might be expected to achieve an adequate antiplatelet effect in healthy Asian subjects, even at lower doses than those assessed in the TRITON-TIMI 38 study. In this study, the antiplatelet effect of prasugrel was evaluated in Japanese coronary artery disease (CAD) patients undergoing percutaneous coronary intervention (PCI).
  
  
  RESULTS
  Eighty-four patients were randomized into four treatment groups: prasugrel 10/2.5mg (loading dose [LD]/maintenance dose [MD]), 15/3.75 mg or 20/5mg, and clopidogrel 300/75 mg. The LD of each regimen was administered the day before PCI, followed by 28-day MD on aspirin background therapy (81-100mg). Antiplatelet effects were evaluated by light transmission aggregometry and VASP assay. The mean inhibition of platelet aggregation (IPA) induced by 20 μM of adenosine diphosphate at 4 hours after LD was higher among the prasugrel 10/2.5mg, 15/3.75 mg and 20/5mg groups compared with the clopidogrel group (12.3%, 20.9%, 29.8% vs. 8.4%, respectively). The proportion of subjects with an IPA of <10% on Day 28 was lower among the prasugrel 15/3.75 mg, and 20/5mg groups than in the clopidogrel group (0%, 6.3% vs. 15.8%, respectively). No "major" or "clinically relevant non-major" bleeding was observed.
  
  
  CONCLUSIONS
  Prasugrel 15 mg LD/3.75 mg MD or higher doses was well tolerated and achieved a more rapid, higher and consistent antiplatelet effect than clopidogrel in Japanese CAD patients undergoing PCI.
authors.affiliation: Department of Cardiovascular Medicine, Kokura Memorial Hospital, Fukuoka, Japan. hyokoi@bu.iij4u.or.jp
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Yokoi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kimura
authors.forename: Takaaki
authors.initials: T
authors.lastname: Isshiki
authors.forename: Hisao
authors.initials: H
authors.lastname: Ogawa
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ikeda
mesh_terms: D000328:Adult; D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000379:methods*; D001241:Aspirin / Q000627:therapeutic use; D000077144:Clopidogrel; D003324:Coronary Artery Disease / Q000097:blood / Q000188:drug therapy* / Q000601:surgery* / Q000628:therapy; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D010879:Piperazines / Q000627:therapeutic use*; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D000068799:Prasugrel Hydrochloride; D058921:Purinergic P2Y Receptor Antagonists / Q000494:pharmacology*; D013876:Thiophenes / Q000627:therapeutic use*; D013988:Ticlopidine / Q000031:analogs & derivatives / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D010879:Piperazines; D010975:Platelet Aggregation Inhibitors; D058921:Purinergic P2Y Receptor Antagonists; D013876:Thiophenes; D000077144:Clopidogrel; D000068799:Prasugrel Hydrochloride; D013988:Ticlopidine; D001241:Aspirin