Enoxaparin as Adjunctive Antithrombin Therapy for ST-Elevation Myocardial Infarction Results of the ENTIRE-Thrombolysis in Myocardial Infarction (TIMI) 23 Trial

Background-ENTIRE-TIMI 23 evaluated enoxaparin with full-dose tenecteplase (TNK) and half-dose TNK plus abciximab. Methods and Results-Patients (n=483) with ST-elevation MI presenting <6 hours from symptom onset were randomized to full-dose TNK and either unfractionated heparin (UFH) (bolus 60 U/kg; infusion 12 U/kg per hour) or enoxaparin (1.0 mg/kg subcutaneously every 12 hours±initial 30 mg intravenous bolus), or half-dose TNK plus abciximab and either UFH (bolus 40 U/kg; infusion 7 U/kg per hour) or enoxaparin (0.3 to 0.75 mg/kg subcutaneously every 12 hours±initial intravenous bolus of 30 mg). With full-dose TNK and UFH, the rate of TIMI 3 flow at 60 minutes was 52% and was 48% to 51% with enoxaparin. Using combination therapy, the rate of TIMI 3 flow was 48% with UFH and 47% to 58% with enoxaparin. The rate of TIMI 3 flow among all UFH patients was 50% and was 51% among enoxaparin patients. Through 30 days, death/recurrent MI occurred in the full-dose TNK group in 15.9% of patients with UFH and 4.4% with enoxaparin (P=0.005). In the combination therapy group, the rates were 6.5% with UFH and 5.5% with enoxaparin. The rate of major hemorrhage with full-dose TNK was 2.4% with UFH and 1.9% with enoxaparin; with combination therapy, it was 5.2% using UFH and 8.5% with enoxaparin. Conclusions-Enoxaparin is associated with similar TIMI 3 flow rates as UFH at an early time point while exhibiting advantages over UFH with respect to ischemic events through 30 days. These findings with enoxaparin are achieved with a similar risk of major hemorrhage.