title: Polyethylene glycol-derivatized cysteine-substitution variants of recombinant staphylokinase for single-bolus treatment of acute myocardial infarction.
abstract: BACKGROUND
  Thrombolytic therapy of acute myocardial infarction (AMI) is evolving toward bolus administration. Derivatization of proteins with polyethylene glycol (PEG) may reduce their clearance.
  
  
  RESULTS
  A staphylokinase (SakSTAR) variant with 12 amino acid substitutions to reduce its antigenicity, SakSTAR (K35A, E65Q, K74R, E80A, D82A, T90A, E99D, T101S, E108A, K109A, K130T, K135R), and with Ser in position 3 mutated into Cys (code SY161), was derivatized with maleimide-PEG with M:(r) of 5,000 (P5), 10,000 (P10), or 20,000 (P20). The PEGylated variants recognized only one third of the antibodies elicited with wild-type SakSTAR in AMI patients. In experimental animals, plasma clearances were reduced 2. 5- to 5-fold with P5, 5- to 20-fold with P10, and 20-fold with P20, and bolus injection induced pulmonary plasma clot lysis at doses inversely related to their clearance. Intravenous bolus injection of 5 mg of the P5, P10, or P20 variants in AMI patients was associated with plasma half-lives (t(1/2alpha)) of 13, 30, and 120 minutes and clearances of 75, 43, and 8 mL/min, respectively, compared with 3 minutes and 360 mL/min for SakSTAR. Injection of 5 mg P5 variant restored TIMI-3 flow within 60 minutes in 14 of 18 AMI patients (78%, 95% CI 55% to 91%) and of 2.5 mg in 7 of 11 patients (63%, 95% CI 35% to 85%), both in the absence of fibrinogen degradation. The immunogenicity of the variants was significantly (P:<0.002) reduced.
  
  
  CONCLUSIONS
  The staphylokinase variant SY161-P5, derivatized with one linear polyethylene glycol molecule of M:(r) 5000, is a promising fibrin-selective agent for single-bolus coronary thrombolysis.
authors.affiliation: Center for Transgene Technology and Gene Therapy, Flanders Interuniversity Institute for Biotechnology, KU Leuven, Belgium desire.collen@med.kuleuven.ac.be
authors.forename: D
authors.initials: D
authors.lastname: Collen
authors.forename: P
authors.initials: P
authors.lastname: Sinnaeve
authors.forename: E
authors.initials: E
authors.lastname: Demarsin
authors.forename: H
authors.initials: H
authors.lastname: Moreau
authors.forename: M
authors.initials: M
authors.lastname: De Maeyer
authors.forename: L
authors.initials: L
authors.lastname: Jespers
authors.forename: Y
authors.initials: Y
authors.lastname: Laroche
authors.forename: F
authors.initials: F
authors.lastname: Van de Werf
mesh_terms: D000208:Acute Disease; D000368:Aged; D003545:Cysteine / Q000737:chemistry; D004795:Enzyme Stability; D005343:Fibrinolytic Agents / Q000276:immunology / Q000493:pharmacokinetics / Q000627:therapeutic use*; D006207:Half-Life; D006801:Humans; D008666:Metalloendopeptidases / Q000737:chemistry / Q000276:immunology / Q000493:pharmacokinetics / Q000627:therapeutic use*; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000378:metabolism; D011092:Polyethylene Glycols / Q000737:chemistry; D011994:Recombinant Proteins / Q000276:immunology / Q000493:pharmacokinetics / Q000627:therapeutic use
chemical_list: D005343:Fibrinolytic Agents; D011994:Recombinant Proteins; D011092:Polyethylene Glycols; D008666:Metalloendopeptidases; C022653:auR protein, Staphylococcus aureus; D003545:Cysteine