Trigen Initiates Clinical Development with a Novel Therapeutic Protein, targeting Thrombosis and the Progression of Atherosclerosis

- PR-15 is a highly innovative platelet adhesion inhibitor with the potential to block arterial thrombosis locally and to retard atherosclerotic plaque growth - Munich, Germany, and London, UK, 13 December 2006 - Trigen, the cardiovascular drug discovery and development company, today announced the initiation of a phase I clinical study with its novel lesion-specific platelet adhesion inhibitor, PR-15, following strong efficacy displayed in pre-clinical models. PR-15 is being evaluated in a Phase I single dose clinical study in 36 volunteers at a site in Germany which aims to define the safety, tolerability and PK/PD profile of the drug candidate. PR-15 is being developed as a novel agent to treat acute arterial thrombosis and prevent progression of atherosclerosis following an acute event. PR-15 is a soluble form of the GPVI receptor on blood platelets. As such, it binds selectively to collagen exposed in ruptured atherosclerotic plaques where it prevents GPVI-mediated platelet adhesion and activation. Such activation normally triggers arterial thrombosis (clot formation), the initiating event in myocardial infarction (heart attack) and stroke. Furthermore, platelet adhesion, activation and subsequent aggregation around ruptured plaques are key events in the progression of atherosclerosis leading to an increased risk of cardiovascular events following an initial acute episode. PR-15 is a lesion-specific anti-thrombotic since it prevents the binding of platelet-bound GPVI to collagen exposed in ruptured atherosclerotic plaques but not elsewhere in the vasculature. This feature gives PR-15 the potential for significant clinical benefit with less bleeding risk as compared to traditional anti-platelet agents as it will not affect normal platelet function, leaving hemostasis undisturbed. Dr Tony Kennedy, VP Development at Trigen commented "We are very excited by the progression of PR-15 into the clinical setting. Given its novel mechanism of action as a platelet adhesion blocker, specific to plaques, PR-15 represents a revolutionary new approach to preventing life-threatening clots within the arteries caused by atherosclerosis." Dr Sophie Combe, VP Clinical Development at Trigen added "PR-15's mode of action has been likened to that of an internal 'sticking plaster', coating the damaged vessel wall and so enabling repair. Naturally, we are very keen to evaluate and demonstrate the clinical utility of this drug." PR-15 was engineered and developed in Trigen's Munich laboratories in Germany and came to Trigen through the merger in April 2005 of Trigen Holdings Plc with ProCorde GmbH. About Trigen Trigen is a biopharmaceutical company, with operations in London and Munich and a leader in cardiovascular drug discovery and development, focusing on thrombosis and vascular dysfunction. Its product pipeline includes clinical-stage candidates TGN 255 and PR-15. The company also has an exciting portfolio of pre-clinical and discovery stage programmes targeting thrombosis, atherosclerosis and other cardiovascular pathologies. In addition, Trigen benefits from two established discovery platforms, SIGSCREEN® and THROMSCAN® which have been applied in collaborations with a number of multinational pharmaceutical companies. For further information on Trigen please refer to the company website at or Contact Details: Ashley Tapp Head of Corporate Communications Trigen Tel: +44 (0)20 7004 2653 Mob: +44 (0)7944 570387 Email: Mary Clark/Halina Kukula Capital MS&L Tel: +44 (0)20 7307 5336/5330 Email: