OASIS Pilot Results Suggest Hirudin Benefit

The preliminary results of the OASIS (Organization for the Assessment of Strategies for Ischemic Syndromes) study, which compared heparin to Hoechst/Behringwerke's hirudin (HBW 023) in patients with unstable angina, have suggested an advantage for hirudin in reducing the rate of myocardial infarction and recurrent angina. The data were presented on August 24 at the 17th European Society of Cardiology meeting in Amsterdam, the Netherlands.

Previous studies have shown that heparin and aspirin reduce the incidence of myocardial infarction or refractory angina in these patients, but despite the use of these drugs about 8% to 10% of patients still develop MI or require urgent interventions for recurrent myocardial ischemia.

Hirudin overcomes some of the theoretical limitations of heparin, such as its weak effect on thrombin already bound to fibrin, as well as some more practical considerations such as reducing interpatient variations in response, which removes the need for careful dose titration and monitoring. Another theoretical advantage is the absence of a hypercoagulable rebound state on cessation of hirudin therapy, which is a problem with unfractionated heparin. Hirudin is thought to be the most specific and potent thrombin inhibitor characterized to date.