Archemix and Regado Announce License Agreement for Antidote-Controlled Aptamers

CAMBRIDGE, MASS., November 17, 2003 - Archemix Corp., a privately held biopharmaceutical company committed to the discovery and development of aptamer-based therapeutics, and Regado Biosciences, a privately held biopharmaceutical company developing antidote-controlled aptamer therapeutics, announced today a license from Archemix to Regado for the discovery and development of antidote-controlled aptamers. Financial terms were not disclosed.

Aptamers are single-stranded nucleic acids (RNA or DNA) that bind to specific protein targets with high affinity and specificity. The first drug from this new class of therapeutics, Eyetech's Macugen, has just demonstrated high efficacy for the treatment of age-related macular degeneration in Phase III clinical trials.

Archemix is the exclusive holder of rights to the SELEX portfolio for all new therapeutic aptamers. Archemix provided Regado with an exclusive world-wide license for the discovery and development of antidote-controlled aptamers to be used for the control of fibrin deposition and platelet adhesion and aggregation. Consisting of over 160 issued patents, the SELEX portfolio is the dominant intellectual property portfolio covering the discovery and use of aptamers.

Working with researchers at Duke University, Regado has developed antidote-controlled aptamer technology, allowing the reversal of an aptamer's therapeutic activity. This technology, as described in the journal Nature (September 5, 2002 pp. 90-94) has been shown to reverse the anti-clotting activity of an aptamer in both cellular and animal models.

 "This license will allow us to generate and develop new, antidote-controlled aptamers for use in the treatment and prevention of thrombosis in the hospital setting (or acute care setting)," stated Doug Gooding, Regado President and CEO. Regado expects to have one of its lead programs targeting coagulation Factor IX or Factor X in the clinic within the next 1-2 years.

According to Errol De Souza, Archemix's President and CEO, "The importance of aptamers as a new class of therapeutics for the prevention and treatment of acute and chronic diseases is becoming broadly appreciated. At Archemix, we have established the dominant intellectual property portfolio covering all new therapeutic aptamers." He continues, "Archemix's aptamer discovery technology in combination with Regado's antidote-controlled aptamer technology will provide physicians with powerful tools for the control drug activity in patients."

About Regado:

Regado Biosciences is an early-stage biopharmaceutical company positioned to become a world leader in the discovery, development, and commercialization of antidote-controlled therapeutics. Its proprietary technology allows Regado to generate highly specific antidotes for each new drug it develops.  The rational design of drug-antidote pairs represents a new paradigm for developing safer therapeutics that addresses multi-billion dollar markets in acute care medicine. The initial focus of the Company is on developing antidote-controlled drugs that prevent or eliminate blood clots ("antithrombotics").

For more information about Regado, please contact Doug Gooding at (919) 949-2990

About Archemix:

Archemix Corp. is a privately held biopharmaceutical company based in Cambridge, Massachusetts. The company's mission is to develop aptamers as a new class of directed therapeutics for the prevention and treatment of chronic and acute disease. Aptamers are single-stranded nucleic acids that form well-defined three-dimensional shapes, allowing them to bind target molecules with extraordinary affinity and specificity. Because of their unique properties, aptamers promise to provide a superior alternative to conventional therapeutic approaches and can potentially be used in a wide range of disease areas, including many of those currently addressed by protein-based therapeutics. Further information on Archemix can be found at http://www.archemix.com.

For more information on Archemix or aptamers, please contact Temin and Company at (212) 588-8788, or email at info@teminandco.com.