Thrombolysis in Pediatric Stroke (TIPS)

OBJECTIVES: 1. To determine the maximal safe dose of intravenous (IV) tPA among three doses (0.75. 0.9, 1.0 mg/kg) for children age 2-17 years within 4.5 hours from onset of acute AIS. 2. To determine the pharmacokinetics of tPA and its inhibitor, plasminogen activator inhibitor in these children. 3. To measure the 3-month neurological outcome in children treated with IV tPA. TRIAL DESIGN: Thrombolysis in Pediatric Stroke (TIPS) is a five-year multi-center international safety and dose-finding study of intravenous (IV) tPA in children with acute AIS to determine the maximal safe dose of intravenous (IV) tPA among three doses (0.75. 0.9, 1.0 mg/kg) for children age 2-17 years within 4.5 hours from onset of acute AIS. An adaptive dose finding method will be applied to escalate across the three dose levels within two age groups: 2-10 years (prepubertal) and 11-17 years. Dose will be escalated based on safety (absence of excess toxicity) with at least 3 children treated at each dose level. Intracranial hemorrhage following stroke can occur even in the absence of thrombolytic therapy, but the risk is increased by the use of thrombolytics. Primary endpoint toxicity is defined as SICH or severe hemorrhage within 36 hours of tPA administration, defined as any of the following: 1. PH2 (parenchymal hemorrhage within 36 hours after tPA administration involving \> 30% of the infarcted area), regardless of whether or not it is associated with clinical deterioration, OR, 2. Any intracranial hemorrhage which is judged to be the most important cause of neurological deterioration. Neurological deterioration is guided by a minimum of change of 2 or more points on the PedNIHSS from the lowest PedNIHSS. At the time of each PedNIHSS assessment, the site PI or co-PI will review the patient's course with the care team to ensure that all changes in neurologic status, including improvements since the last assessment by the study team, are captured, OR, 3. Any hemorrhage that results in the need for transfusion, need to discontinue study drug, surgical evacuation of hemorrhage, or death. TIPS will determine the pharmacokinetics of tPA and its inhibitor, plasminogen activator inhibitor, including free tPA, PAI-1, and tPA antigen in children receiving IV tPA for acute AIS. In addition, TIPS will measure the 3-month neurological outcome in children treated with IV tPA. TRIAL POPULATION: TIPS will enroll a maximum of 18 children age 2-10 years and maximum of 18 children age 11-17 years within 4.5 hours of the onset of acute AIS. On MRA or CTA they will have partial or complete occlusion of the artery, consistent with focal impairment of the arterial flow, that correlates with the clinical deficit. TIPS STUDY INTERVENTION: Investigation labeled tPA will be obtained for all sites by the Core Pharmacy as commercially available recombinant tPA (Genentech as Activase®) for IV administration. The Bayesian method of toxicity probability intervals will be used to select one of the following three dose tiers (0.75, 0.9, 1.0 mg/kg) of IV tPA. The dose escalation for the two age groups (2-10, 11-17 years) will be performed independently. The maximum dose for each tier will be reached at a weight of 90 kg.