BCH-2763, a Novel Potent Parenteral Thrombin Inhibitor, Is an Effective Antithrombotic Agent in Rodent Models of Arterial and Venous Thrombosis – Comparisons with Heparin, r-Hirudin, Hirulog, Inogatran and Argatroban
Carolyn D. Finkle
1
From BioChem Therapeutic Inc., Laval, Quebec, Canada
,
Annie St. Pierre
,
Lorraine Leblond
1
From BioChem Therapeutic Inc., Laval, Quebec, Canada
,
Isabelle Deschenes
1
From BioChem Therapeutic Inc., Laval, Quebec, Canada
,
John DiMaio
1
From BioChem Therapeutic Inc., Laval, Quebec, Canada
,
Peter D. Winocour
1
From BioChem Therapeutic Inc., Laval, Quebec, Canada
Current clinical use of heparin as an antithrombotic agent is limited by suboptimal efficacy and safety considerations. Thrombin’s central role in thrombosis makes it an attractive target to develop more effective and safer antithrombotic agents. BCH-2763 is a novel, potent (Ki: 0.11 nM), low molecular weight (1.51 kDa), bivalent direct thrombin inhibitor. The antithrombotic efficacy of BCH-2763 in vivo following i.v. bolus plus infusion in rats was compared in arterial and venous thrombosis models with two other bivalent direct thrombin inhibitors, r-hirudin and hirulog, with two catalytic site-directed thrombin inhibitors, inogatran and argatroban, and with heparin. In vivo efficacy was related to inhibition in vitro of fibrin clot formation, thrombin-induced aggregation of rat or human washed platelets and activity of free and plasma clot-bound thrombin. All the direct thrombin inhibitors were effective on both arterial and venous thrombosis at markedly lower fold aPTT increases than heparin. The antithrombotic doses of all inhibitors against venous thrombosis were less than against arterial thrombosis. The rank order of potency based on doses (mg/kg/h) required for full efficacy against arterial thrombosis was BCH-2763 (1.2) inogatran (1.5) r-hirudin (1.8) hirulog (3.3) argatroban ( 3.0); heparin required a markedly higher dose (5.7). In venous thrombosis the doses required for full efficacy were substantially lower for the bivalent (BCH-2763: 0.12; r-hirudin: 0.12; hirulog: 0.18) than for the catalytic site-directed (inogatran: 0.48; argatroban: 0.90) thrombin inhibitors; the dose required for heparin was 0.19. All the direct thrombin inhibitors caused similar shifts in aPTT at doses required to inhibit arterial thrombosis, but BCH-2763 inhibited venous thrombosis at lower aPTT fold increases. In vivo antithrombotic efficacy of direct thrombin inhibitors correlated with their inhibitory activity in vitro against fibrin clot formation and platelet aggregation. In contrast to heparin, all the direct thrombin inhibitors inhibited plasma clot-bound thrombin, but the relative IC50s did not correlate with their antithrombotic efficacy. In summary, direct thrombin inhibitors are more effective than heparin in inhibiting arterial and venous thrombosis in rats with less aPTT increases. BCH-2763 is effective at lower doses than the other direct thrombin inhibitors and for venous thrombosis at a smaller aPTT increase. BCH-2763 may offer an improved therapeutic index in the treatment of thromboembolic complications over heparin and other direct thrombin inhibitors.
References
1
Weitz JI.
Biological rationale for the therapeutic role of specific antithrom-bins. Coronary Artery Disease 1996; 7: 409-19.
4
Hauptmann J,
Markwardt F.
Pharmacologic aspects of the development of selective synthetic thrombin inhibitors as anticoagulants. Semin Thromb Hemostas 1992; 18: 200-17.
8
Rydel TJ,
Ravichandran KG,
Tulinsky A,
Bode W,
Huber R,
Roitsch C,
Fenton II JW.
The structure of a complex of recombinant hirudin and human alpha-thrombin. Science 1990; 249: 277-80.
10
Hilpert K,
Ackermann J,
Banner DW,
Gast A,
Gubernator K,
Hadvary P,
Labler L,
Muller K,
Schmid G,
Tschopp TB,
van de Waterbeemd H.
Design and synthesis of potent and highly selective thrombin inhibitors. J Med Chem 1994; 37: 3889-901.
12
DiMaio J,
Ni F,
Gibbs B,
Konishi Y.
A new class of potent thrombin inhibitors that incorporates a scissile pseudopeptide bond. FEBS 1991; 282: 47-52.
13
DiMaio J,
Gibbs B,
Lefebvre J,
Konishi Y,
Munn D,
Yue S.
Synthesis of a homologous series of ketomethylene arginyl pseudodipeptides and application to low molecular weight hirudin-like thrombin inhibitors. J Med Chem 1992; 35: 3331-41.
16
Ginsberg JS,
Nurmohamed MT,
Gent M,
MacKinnon B,
Sicurella J,
Brill-Edwards P,
Levine MN,
Panju AA,
Powers P,
Stevens P,
Turpie AGG,
Weitz J,
Buller HR,
ten Cate JW,
Neemeh J,
Adelman B,
Fox I,
Maraganore J,
Hirsh J.
Use of hirulog in the prevention of venous thrombosis after major hip or knee surgery. Circulation 1994; 90: 2385-9.
17
Serruys PW,
Herrman JPR,
Simon R,
Rutsch W,
Bode C,
Laarman GJ,
van Dijk R,
van den Bos AA,
Umans VAWM,
Fox KAA,
Close P,
Deckers JW.
for the Helvetica Investigators. A comparison of hirudin with heparin in the prevention of restenosis after coronary angioplasty. N Engl J Med 1995; 333: 757-63.
18
Bittl JA,
Strony J,
Brinker JA,
Ahmed WH,
Meckel CR,
Chaitman BR,
Maraganore J,
Deutsch E,
Adelman B.
for the hirulog angioplasty study investigators. Treatment with bivalirudin (hirulog) as compared with heparin during coronary angioplasty for unstable or postinfarction angina. N Engl J Med 1995; 333: 764-9.
19
Antman EM for the TIMI 9B investigators..
Hirudin in acute myocardial infarction. Thrombolysis and thrombin inhibition in myocardial infarction (TIMI) 9B trial. Circulation 1996; 94: 911-21.
24
The Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO) IIb Investigators..
A comparison of recombinant hirudin with heparin for the treatment of acute coronary syndromes. N Engl J Med 1996; 335: 775-82.
27
Gustafsson D,
Elg M,
Lenfors S,
Borjesson I,
Teger-Nilsson A-C.
Effects of inogatran, a new low-molecular weight thrombin inhibitor, in rat models of venous and arterial thrombosis, thrombolysis and bleeding time. Blood Coagulation and Fibrinolysis 1996; 7: 69-79.
28
Andersen K,
Dellborg M,
Emanuelsson H,
Grip L,
Swedberg K.
Thrombin inhibition with inogatran for unstable angina pectoris: evidence for reactivated ischaemia after cessation of short-term treatment. Coronary Artery Disease 1996; 7: 673-81.
31
Maraganore JM,
Bourdon P,
Jablonski J,
Ramachandran KL,
Fenton II. JW.
Design and characterization of hirulogs: a novel class of bivalent peptide inhibitors of thrombin. Biochem 1990; 29: 7095-107.
34
Berry CN,
Girard D,
Lochot S,
Lecoffre C.
Antithrombotic actions of argatroban in rat models of venous, “mixed” and arterial thrombosis, and its effects on the tail transection bleeding time. Br J Pharmacol 1994; 113: 1209-14.
35
DiMaio J,
Gibbs B,
Munn D,
Lefebvre J,
Ni F,
Konishi Y.
Bifunctional thrombin inhibitors based on the sequence of hirudin45-65
. J Biol Chem 1990; 265: 21698-703.
36
Krstenansky JL,
Mao SJT.
Antithrombin properties of C-terminus of hirudin using synthetic unsulfated N(alpha)-acetyl-hirudin45-65
. FEBS 1987; 211: 10-6.
39
Winocour PD,
Richardson M,
Kinlough-Rathbone RL.
Continued platelet interaction with de-endothelialized aortae associated with slower re-endothelialization and more extensive intimal hyperplasia in spontaneously diabetic BB Wistar rats. Int J Exp Path 1993; 74: 603-13.
40
Berry CN,
Girardot C,
Lecoffre C,
Lunven C.
Effects of the synthetic thrombin inhibitor argatroban on fibrin- or clot-incorporated thrombin: comparison with heparin and recombinant hirudin. Thromb Haemost 1994; 72: 381-6.
41
Betz A,
Hopkins PCR,
Le Bonniec BF,
Stone SR.
Contribution of interactions with the core domain of hirudin to the stability of its complex with thrombin. Biochem J 1994; 298: 507-10.
42
Hara T,
Yokoyama A,
Morishima Y,
Kunitada S.
Species differences in anticoagulant and anti-Xa activity of DX-9065a, a highly selective factor Xa inhibitor. Thromb Res 1995; 80: 99-104.
45
Gast A,
Tschopp TB,
Schmid G,
Hilpert K,
Ackermann J.
Inhibition of clot-bound and free (fluid-phase thrombin) by a novel synthetic thrombin inhibitor (Ro 46-6240), recombinant hirudin and heparin in human plasma. Blood Coagulation and Fibrinolysis 1994; 5: 879-87.
46
Weitz JI,
Huboda M,
Massel D,
Maraganore J,
Hirsh J.
Clot-bound thrombin is protected from inhibition by heparin-antithrombin III but is susceptible to inactivation by antithrombin III-independent inhibitors. J Clin Invest 1990; 86: 385-91.
47
Teger-Nilsson A-C,
Gryzander E,
Andersson S,
Englund M,
Mattsson C,
Ulvinge J-C,
Gustafsson D.
In vitro properties of inogatran, a new selective low molecular weight inhibitor of thrombin. Thromb Haemost 1995; 73: 1633.
48
Klement P,
Borm A,
Hirsh J,
Maraganore J,
Wilson G,
Weitz J.
The effect of thrombin inhibitors on tissue plasminogen activator induced thrombolysis in a rat model. Thromb Haemost 1992; 68: 64-8.