Bivalirudin was launched in New Zealand as an anticoagulant for i.v. treatment of
patients with unstable angina undergoing percutaneous transluminal coronary angioplasty.
Bivalirubin is a synthetic 20 amino acid peptide rationally modeled on hirudin (residues 53-
64), the most potent and specific naturally-occuring known inhibitor of thrombin, the
enzyme that plays a key role in hemostasis and blood clot formation. This peptide is a
direct thrombin inhibitor that maintains the unique bivalent binding properties of hirudin to
the catalytic site and to the fibrin-recognition exosite of the enzyme, so acting directly on
thrombin with high affinity and specificity. In vitro studies demonstrated that alpha- and
zeta-thrombins, both with the higher fibrinogen-procoagulant activities, were inhibited. In
rats receiving high doses of bivalirudin, the platelet deposition in carotide was reduced by
63% compared to controls. The results of clinical studies, conducted only in patients
receiving concomitant aspirin, suggested that the use of bivalirudin was more efficacious
and more predictable than unfractionated heparin, with fewer bleeding complications.
Despite some unresolved developmental issues, the attractive properties of this novel
agent could make it a useful alternative to heparin in a variety of coagulation disorders.
