A synthetic factor-Xa inhibitor (ORG31540/SR9017A) as an adjunct to fibrinolysis in acute myocardial infarction. The PENTALYSE study

BACKGROUND: ORG31540/SR90107A, a synthetic pentasaccharide, is a selective inhibitor of factor-Xa. It was hypothesized that prolonged factor-Xa inhibition with pentasaccharide may be an effective and safe antithrombotic co-therapy in acute myocardial infarction. METHODS AND RESULTS: Patients (n=333) with evolving ST-segment elevation acute myocardial infarction were treated with aspirin and alteplase and randomized to unfractionated heparin, given intravenously during 48 to 72 h, or to a low, medium or high dose of pentasaccharide, administered daily for 5 to 7 days, intravenously on the first day, then subcutaneously. Coronary angiography was performed at 90 min and on days 5 to 7. Thrombolysis in Myocardial Infarction (TIMI) flow grade 3 rates at 90 min were similar in the four treatment groups. Among patients with TIMI 3 flow at 90 min and who did not undergo a coronary intervention (n=155), a trend towards less reocclusion of the infarct-related vessel on days 5 to 7 was observed with pentasaccharide: 0.9% vs 7.0% with unfractionated heparin (P=0.065). Also, fewer revascularizations during the 30-day follow-up period were performed in patients given pentasaccharide (39% vs 51% for unfractionated heparin;P=0.054). The primary safety end-point, the combined incidence of intracranial haemorrhage and need for blood transfusion, was identical with pentasaccharide and unfractionated heparin (7.1%). One non-fatal intracranial haemorrhage occurred in the 241 patients given pentasaccharide (0.4%). CONCLUSIONS: In this study, pentasaccharide given together with alteplase was safe and as effective as unfractionated heparin in restoring coronary artery patency. Prolonged administration of pentasaccharide was associated with a trend towards less reocclusion and fewer revascularizations. Selective factor-Xa-inhibition seems to be an attractive therapeutic concept in patients presenting with ST-segment elevation acute myocardial infarction.