title: Efficacy and safety of fondaparinux versus enoxaparin in patients with acute coronary syndromes treated with glycoprotein IIb/IIIa inhibitors or thienopyridines: results from the OASIS 5 (Fifth Organization to Assess Strategies in Ischemic Syndromes) trial.
abstract: OBJECTIVE
  This study sought to evaluate the relative safety and efficacy of fondaparinux and enoxaparin in patients with acute coronary syndromes (ACS) treated with glycoprotein (GP) IIb/IIIa inhibitors or thienopyridines.
  
  
  BACKGROUND
  The OASIS 5 (Fifth Organization to Assess Strategies in Ischemic Syndromes) trial showed that fondaparinux reduced major bleeding by 50% compared with enoxaparin while preserving similar efficacy. Whether this benefit is consistent in the presence or absence of concurrent antiplatelet therapy with clopidogrel and GP IIb/IIIa inhibitors is unknown.
  
  
  METHODS
  Patients with ACS (n = 20,078) were randomized as a part of the OASIS 5 trial to receive either fondaparinux or enoxaparin. The use of GP IIb/IIIa inhibitors or thienopyridines was at the discretion of the treating physician. A Cox proportional hazard model was used to compare outcomes.
  
  
  RESULTS
  Of the 20,078 patients randomized, 3,630 patients received GP IIb/IIIa and 13,531 received thienopyridines. There was a 40% reduction in major bleeding with fondaparinux compared with enoxaparin in those treated with GP IIb/IIIa (5.2% vs. 8.3%, hazard ratio [HR]: 0.61, p < 0.001). A similar reduction was found in those treated with thienopyridines (3.4% vs. 5.4%, HR: 0.62, p < 0.001). Ischemic events were similar between the groups, resulting in a superior net clinical outcome (death, myocardial infarction, refractory ischemia, or major bleeding) favoring fondaparinux (GP IIb/IIIa subgroup 14.8% vs. 18.9%, HR: 0.77, p = 0.001 and thienopyridines subgroup 11.0% vs. 13.2%, HR: 0.82, p < 0.001).
  
  
  CONCLUSIONS
  In patients receiving GP IIb/IIIa inhibitors or thienopyridines, fondaparinux reduces major bleeding and improves net clinical outcome compared with enoxaparin.
authors.affiliation: Department of Medicine, Hamilton Health Sciences, Population Health Research Institute, McMaster University, McMaster Clinic Room 630, Hamilton General Hospital, 237 Barton Street East, Hamilton, Ontario L8L 2X2, Canada. jollyss@mcmaster.ca
authors.forename: Sanjit S
authors.initials: SS
authors.lastname: Jolly
authors.forename: David P
authors.initials: DP
authors.lastname: Faxon
authors.forename: Keith A A
authors.initials: KA
authors.lastname: Fox
authors.forename: Rizwan
authors.initials: R
authors.lastname: Afzal
authors.forename: William E
authors.initials: WE
authors.lastname: Boden
authors.forename: Petr
authors.initials: P
authors.lastname: Widimsky
authors.forename: P Gabriel
authors.initials: PG
authors.lastname: Steg
authors.forename: Vicent
authors.initials: V
authors.lastname: Valentin
authors.forename: Andrez
authors.initials: A
authors.lastname: Budaj
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Granger
authors.forename: Campbell D
authors.initials: CD
authors.lastname: Joyner
authors.forename: Susan
authors.initials: S
authors.lastname: Chrolavicius
authors.forename: Salim
authors.initials: S
authors.lastname: Yusuf
authors.forename: Shamir R
authors.initials: SR
authors.lastname: Mehta
mesh_terms: D054058:Acute Coronary Syndrome / Q000188:drug therapy*; D000368:Aged; D000925:Anticoagulants / Q000494:pharmacology / Q000627:therapeutic use*; D004359:Drug Therapy, Combination; D017984:Enoxaparin / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D000077425:Fondaparinux; D006801:Humans; D008297:Male; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000037:antagonists & inhibitors / Q000187:drug effects; D011134:Polysaccharides / Q000494:pharmacology / Q000627:therapeutic use*; D011725:Pyridines / Q000494:pharmacology / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D000925:Anticoagulants; D017984:Enoxaparin; D010975:Platelet Aggregation Inhibitors; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D011134:Polysaccharides; D011725:Pyridines; C446540:thienopyridine; D000077425:Fondaparinux