Administering a second dose of intravenous TNK in acute ischemic stroke: Rationale and design of a pilot clinical trial

BackgroundA single dose of intravenous thrombolysis (IVT) is the only effective acute treatment for ischemic stroke patients who do not qualify for endovascular thrombectomy. However, at least 50% of patients treated with only IVT remain disabled. Studies suggest that incomplete recanalization and reperfusion of the distal or micro-vasculature contribute to incomplete recovery after a single dose of IVT. Single IVT doses above the approved doses produce excessive bleeding. Another strategy might be to provide a more sustained lytic effect by administering a second dose of IVT. Tenecteplase (TNK) pharmacokinetics and preliminary data from clinical trials suggest a second full dose might be given safely 45 minutes after the first dose. MethodsWe propose a phase 2a preliminary safety study of a second dose of TNK given 45-60 minutes after the first dose in 20 patients not responding to the first dose. Patients will be included if they qualify for and receive TNK within 3 hours of symptom onset, do not qualify for thrombectomy, sign informed consent, have NIHSS [≥] 6 45 minutes later and no bleeding on a repeat CT scan, and can receive the second TNK dose within 4.5 hours of onset. ResultsPrimary outcome will be symptomatic intracerebral hemorrhage (type 2 parenchymal hemorrhage or parenchymal hemorrhage remote from the area of infarction with neurological deterioration) or major systemic bleeding; secondary outcomes will include other definitions of intracerebral hemorrhage and modified Rankin scale at hospital discharge and 90 days after stroke. The study will be stopped and dual full dose TNK therapy considered unsafe if 4 symptomatic or major bleeding events occur. ConclusionWe propose the first study of two sequential doses of TNK in stroke patients. If successful, this study will be followed by a larger phase 2b controlled safety confirmation and pilot efficacy study.