THR-18's Pharmacokinetics and Pharmacodynamics in Subjects With Acute Ischemic Stroke Treated With tPA

The purpose of this study is to test the experimental drug "THR-18" given together with the drug "tissue plasminogen activator" for the treatment of stroke. Tissue plasminogen activator is also called "tPA". Strokes often result from blockade of blood supply caused by blood clots forming within the blood vessel feeding the brain. Such strokes are called "Ischemic strokes". Treatment of these strokes is aimed at breaking up the blood clot(s) and renewing the blood flow before further parts of the brain die. Breaking up the blood clot is possible with the drug tPA when it is injected into a vein shortly after the stroke starts. However, along with breaking up the blood clot, tPA sometimes causes adverse effects, for example, it may cause bleeding. THR-18, the drug tested in this study, is meant to bind to tPA and reduce its adverse effects without stopping tPA's breaking up of the blocking blood clot. The primary purpose of this study is to evaluate the safety of THR-18 in acute ischemic stroke patients who are treated in parallel with tPA. Another purpose of this study is to investigate levels of THR-18 and tPA in the blood stream at different time points after they are injected, at the same time, into a vein. In addition, this study will measure tPA's effect on blood clot dissolution when tPA is given with and without THR-18. The study will also study the effect THR-18 may have on signals of brain damage that can be found in the blood after stroke: these signals of brain damage are small proteins called S100B and matrix metalloproteinase (MMP)-9. These proteins are released into the blood stream when the brain is injured. The safety evaluation of THR-18 in this study will be done in comparison to placebo. Placebo is a drug that looks exactly like THR-18 but has no activity. Three doses of THR-18 will be tested, one after the other, in three groups of patients. In each group, some patients will receive THR-18 and some will receive placebo. This clinical study will