title: Specificity and selectivity profile of EP217609: a new neutralizable dual-action anticoagulant that targets thrombin and factor Xa.
abstract: EP217609 is a new dual-action parenteral anticoagulant that combines an indirect factor Xa inhibitor (fondaparinux analog) and a direct thrombin inhibitor (α-NAPAP analog) in a single molecule together with a biotin tag to allow avidin neutralization. EP217609 exhibits an unprecedented pharmacologic profile in showing high bioavailability, long plasma half-life, and potent antithrombotic activity in animals without the complications of thrombin rebound. Here we report the exceptional specificity and selectivity profile of EP217609. EP217609 inhibited thrombin with rapid kinetics (k(on) > 10(7)M(-1)s(-1)), a high affinity (K(I) = 30-40pM), and more than 1000-fold selectivity over other coagulation and fibrinolytic protease targets, comparing favorably with the best direct thrombin inhibitors known. EP217609 bound antithrombin with high affinity (K(D) = 30nM) and activated the serpin to rapidly (k(ass) ∼ 10(6)M(-1)s(-1)) and selectively (> 20-fold) inhibit factor Xa. The dual inhibitor moieties of EP217609 acted largely independently with only modest linkage effects of ligand occupancy of one inhibitor moiety on the potency of the other (∼ 5-fold). In contrast, avidin binding effectively neutralized the potency of both inhibitor moieties (20- to 100-fold). These findings demonstrate the superior anticoagulant efficacy and rapid avidin neutralizability of EP217609 compared with anticoagulants that target thrombin or factor Xa alone.
authors.affiliation: Center for Molecular Biology of Oral Diseases, University of Illinois at Chicago, 60612, USA. stolson@uic.edu
authors.forename: Steven T
authors.initials: ST
authors.lastname: Olson
authors.forename: Richard
authors.initials: R
authors.lastname: Swanson
authors.forename: Maurice
authors.initials: M
authors.lastname: Petitou
mesh_terms: D000465:Algorithms; D000925:Anticoagulants / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D000991:Antithrombins / Q000378:metabolism / Q000494:pharmacology; D001360:Avidin / Q000378:metabolism / Q000494:pharmacology; D001667:Binding, Competitive / Q000187:drug effects; D001710:Biotin / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D015951:Factor Xa / Q000378:metabolism; D065427:Factor Xa Inhibitors; D006801:Humans; D007700:Kinetics; D015394:Molecular Structure; D009844:Oligosaccharides / Q000378:metabolism / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D013917:Thrombin / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D000925:Anticoagulants; D000991:Antithrombins; C547750:EP 217609; D065427:Factor Xa Inhibitors; D009844:Oligosaccharides; D001360:Avidin; D001710:Biotin; D013917:Thrombin; D015951:Factor Xa