A recombinant therapeutic agent which is chemically identical to or similar to endogenous tissue plasminogen activator (tPA). tPA is a serine protease which converts plasminogen to plasmin, a fibrinolytic enzyme. Upon administration, alteplase increases plasmin enzymatic activity, resulting in hyperfibrinolysis and potential dissolution of a thrombus or embolism. Check for active clinical trials using this agent. (NCI Thesaurus)