Dose‐ranging study with a new two‐chain rt‐PA in patients with acute myocardial infarction: A multicenter trial

Tissue-type plasminogen activator (t-PA) derived from a melanoma cell line was first used in patients with acute myocardial infarction in the early 1980s. Recombinant DNA technology then allowed production of large amounts of t-PA. The TIMI-I trial used a two-chain recombinant (rt-PA) product. A predominantly single-chain rt-PA (alteplase) was used in the majority of the TIMI II trial. The present study used a different form of two-chain rt-PA (duteplase) to determine the effective dose for thrombolysis at 60 min, and to evaluate time to reperfusion, reocclusion at 72-96 h, coagulation profiles, and bleeding events. Duteplase was given intravenously to 75 patients a mean of 3.8 +/- 1 h after the onset of myocardial infarction. Following angiography demonstrating coronary occlusion, 23 patients received a low dose of duteplase [0.16-0.29 million international units per kilogram (MIU/kg)] over 60 min followed by a 5-h infusion in conjunction with heparin, 25 patients received a middle dose (0.30-0.41 MIU/kg) and 23 patients received a high dose (0.43-0.74 MIU/kg). Angiography was then performed every 15 min x 4. Progressive recanalization occurred over 60 min (median 45 min) with an overall success rate of 59% (mean 60-min dose: 0.37 MIU/kg). No dose-response relationship was observed. The reocclusion rate was 9% at 72-96 h. Reductions in fibrinogen and plasminogen correlated with dose, but clinical events did not.(ABSTRACT TRUNCATED AT 250 WORDS)