Staphylokinase is a profibrinolytic agent that forms a 1:1 stoichiometric complex with
plasminogen which, following conversion to
plasmin, activates other
plasminogen molecules to
plasmin. The
plasmin,
staphylokinase complex, unlike the
plasmin,
streptokinase complex, is rapidly inhibited by alpha 2-antiplasmin. In a plasma milieu,
staphylokinase is able to dissolve
fibrin clots without associated
fibrinogen degradation. This
fibrin-specificity of
staphylokinase is the result of reduced inhibition by alpha 2-antiplasmin of
plasmin,
staphylokinase complex bound to
fibrin, recycling of
staphylokinase from the
plasmin,
staphylokinase complex following inhibition by alpha 2-antiplasmin, and prevention of the conversion of
plasminogen,
staphylokinase to
plasmin,
staphylokinase by alpha 2-antiplasmin. In several experimental animal models,
staphylokinase appears to be equipotent to
streptokinase for the dissolution of whole blood or plasma clots, but significantly more potent for the dissolution of platelet-rich or retracted thrombi. The feasibility of
fibrin-specific coronary thrombolysis with an
intravenous infusion over 30 min of 10 mg recombinant
staphylokinase was demonstrated in two small pilot studies in patients with acute
myocardial infarction with angiographically confirmed total occlusion of the
infarct-related coronary artery. However,
neutralizing antibodies against
staphylokinase were demonstrable from the third week on in all patients. Definition of the therapeutic benefit of recombinant
staphylokinase will require more detailed dose-finding studies followed by randomized efficacy studies against other
thrombolytic agents. An interim analysis after 50 patients of a randomized trial of recombinant
tissue-type plasminogen activator versus
staphylokinase in patients with acute
myocardial infarction revealed similar rates of coronary patency at 90 minutes but a significantly higher
fibrin specificity of the latter compound.