A Pilot Dose-Escalation Safety Study of Tenecteplase in Acute Ischemic Stroke

BACKGROUND AND PURPOSE: Recombinant tissue-type plasminogen activator (rtPA) is the only approved treatment in acute ischemic stroke. However, intracerebral hemorrhage (ICH) occurs in 6.4% of patients treated with rtPA and limits its use. Tenecteplase (TNK) is a modified form of rtPA, with longer half-life and greater fibrin specificity. Patients after myocardial infarction had fewer systemic hemorrhages when treated with TNK compared with rtPA. This open-label, dose-escalation safety study was conducted to develop initial experience with TNK in the treatment of ischemic stroke. METHODS: Eligible patients were treated with an intravenous bolus infusion of TNK within 3 hours of stroke onset. The dose escalation was conducted in tiers of 25 patients, starting at 0.1 mg/kg, to a planned maximum of 0.6 mg/kg. The primary endpoint was symptomatic intracranial hemorrhage within 36 hours of treatment. All patients were followed-up for 3 months. RESULTS: Eighty-eight (88) patients were treated in 4 dosing tiers. In the first 3 tiers (0.1, 0.2, 0.4 mg/kg) of 25 patients each, no symptomatic and 2 (8%), 8 (32%), and 7 (28%) asymptomatic ICHs occurred. Enrollment into the fourth tier at 0.5 mg/kg was closed after 2 of 13 patients (15%) had symptomatic and 3 (23%) had asymptomatic ICHs. Overall, modified Rankin scores at 3 months were similar to those of historical controls treated with rtPA and not significantly different between treatment groups. CONCLUSIONS: TNK doses of 0.1 to 0.4 mg/kg are safe in ischemic stroke. Future trials are needed to compare the effect of TNK on neurological outcome and safety as compared with rtPA.