ARCHEMIX BEGINS STUDIES OF ANTIPLATELET APTAMER

Archemix announced it has begun patient dosing in its first-in-human Phase I study of ARC1779. The Phase I clinical development program began with first-in-human dosing in an initial healthy volunteer study in late December 2006 and is expected to continue into the second quarter of this year.

ARC1779 represents a novel therapeutic principle -- the reduction of platelet aggregation and thrombosis by inhibition of von Willebrand Factor (vWF). Previously completed experiments in human blood samples and in animal models of disease have shown that ARC1779 binds specifically to activated vWF and blocks the binding of vWF to blood platelets, resulting in the inhibition of platelet-dependent clot formation at sites of arterial vessel injury, while preserving normal platelet function and blood clotting in the remainder of the body, according to the company

The Phase I program consists of two studies. The first will investigate the safety, tolerability, pharmacokinetics and pharmacodynamics of single intravenous bolus and bolus plus infusion administration of ARC1779 in healthy volunteer subjects. The second will study the potential pharmacokinetic and pharmacodynamic interactions of intravenous bolus ARC1779 with two standard anti-thrombotic drug therapies -- orally administered aspirin and clopidogrel -- in healthy volunteer subjects.

Planning is now under way to enable the start of Phase II in both cardiology and hematology indications at the end of this year. The Phase II program will be based on the results of the Phase I program as well as the results of ongoing laboratory studies of the effect on thrombosis and platelet function when ARC1779 is added to blood samples drawn from those patient populations.

Aptamers are single-stranded nucleic acids that form well-defined, three-dimensional shapes, allowing them to bind target molecules in a manner that is conceptually similar to antibodies, according to the company.