Thrombolytic and pharmacokinetic properties of a recombinant chimeric plasminogen activator consisting of a fibrin fragment D-dimer specific humanized monoclonal antibody and a truncated single-chain urokinase.
A recombinant chimeric plasminogen activator consisting of a humanized monoclonal antibody specific for cross-linked human fibrin (MA-15C5Hu) and a 32 kDa single-chain urokinase-type plasminogen activator (scu-PA-32k) comprising amino acids Leu144-Leu411, MA-15C5Hu/scu-PA-32k, was previously found to have a 12-fold higher fibrinolytic potency than recombinant scu-PA-32k towards a human plasma clot in a human plasma milieu in vitro (Vandamme et al., Eur J Biochem 1992; 205: 139-46). Therefore, the thrombolytic and pharmacokinetic properties of MA-15C5Hu/scu-PA-32k were compared with those of recombinant single-chain urokinase-type plasminogen activator (scu-PA) in 3 different venous thrombosis models in vivo. In hamsters with a pulmonary embolus consisting of a human plasma clot, the thrombolytic potency (% lysis per dose in mg/kg administered) of MA-15C5Hu/scu-PA-32k was 23-fold higher than that of scu-PA (p less than 0.0005). In rabbits with a jugular vein clot prepared from human plasma, the thrombolytic potency of MA-15C5Hu/scu-PA-32k was 11-fold higher than that of scu-PA (p = 0.012). In baboons with an autologous whole blood clot in the femoral vein, the chimera had a 5-fold higher thrombolytic potency than scu-PA. In all three animal species, the clearance of the chimera was 10- to 27-fold reduced as compared to scu-PA. The specific thrombolytic activity (% lysis per micrograms/ml steady-state plasma u-PA antigen) was increased up to 7-fold with MA-15C5Hu/scu-PA-32k as compared with scu-PA, which is indicative of targeting of the chimera to the clot. No fibrinogen breakdown or alpha 2-antiplasmin depletion was observed during thrombolysis with the chimera. Thus, MA-15C5Hu/scu-PA-32k constitutes a recombinant chimeric plasminogen activator with a significantly enhanced thrombolytic potency in 3 different animal models of venous thrombosis.
Dewerchin
M
M
Center for Thrombosis and Vascular Research, University of Leuven, Belgium.
Vandamme
A M
AM
Holvoet
P
P
De Cock
F
F
Lemmens
G
G
Lijnen
H R
HR
Stassen
J M
JM
Collen
D
D
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D006224:Cricetinae; D004195:Disease Models, Animal; D005338:Fibrin Fibrinogen Degradation Products / Q000276:immunology; D005342:Fibrinolysis / Q000187:drug effects*; D006801:Humans; D066298:In Vitro Techniques; D010215:Papio; D010960:Plasminogen Activators / Q000493:pharmacokinetics / Q000494:pharmacology*; D011655:Pulmonary Embolism / Q000188:drug therapy; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000493:pharmacokinetics / Q000494:pharmacology; D013924:Thrombophlebitis / Q000188:drug therapy; D014568:Urokinase-Type Plasminogen Activator / Q000493:pharmacokinetics / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D005338:Fibrin Fibrinogen Degradation Products; D011993:Recombinant Fusion Proteins; C036309:fibrin fragment D; D010960:Plasminogen Activators; D014568:Urokinase-Type Plasminogen Activator