Archemix CEO to Present at 25th Annual SG Cowen Health Care Conference

CAMBRIDGE, MA - March 9, 2005 - Archemix Corp., the privately-held biopharmaceutical company focused on discovering and developing aptamer-based therapeutics, announced today that Dr. Errol De Souza, Archemix's President and Chief Executive Officer, will present at the SG Cowen's 25th Annual Health Care Conference at the Boston Marriott Copley Place on Thursday, March 17, 2005 at 11:30 a.m. (EST). In his 25-minute presentation, Dr. De Souza will provide an update of Archemix's product portfolio and business developments and review goals for 2005.

About Aptamers

Aptamers are single-stranded nucleic acids that form well-defined three-dimensional shapes, allowing them to bind to target molecules in a manner that is conceptually similar to antibodies. Aptamers combine the optimal characteristics of small molecules and antibodies, including high specificity and affinity, chemical and biological stability, low toxicity and immunogenicity and the ability to target protein-protein interactions. In contrast to monoclonal antibodies, aptamers are chemically synthesized rather than biologically expressed, offering a significant cost advantage. As therapeutic agents, aptamers have demonstrated clinical biological efficacy and have excellent, tunable pharmacokinetic properties.

About Archemix Corp.

Archemix Corp. is a privately-held biopharmaceutical company based in Cambridge, Massachusetts. The company's mission is to develop aptamers as a class of directed therapeutics for the treatment of human disease. Because of their unique properties and proven efficacy, aptamers are a superior alternative to biologics and small molecules and will be a major class of drugs for the treatment of unmet medical needs.

Archemix's aptamer expertise is complimented by a dominant patent estate comprised of over 220 issued and 230 pending patents covering the identification, composition and use of therapeutic aptamers. In addition to the company's core aptamer generation technology, Archemix possesses strong expertise in both preclinical and clinical drug development. Further information about Archemix can be found at http://www.archemix.com.

For further information or to speak with Dr. Errol De Souza, please contact Davia Temin or Jane Trombley of Temin and Company at 212.588.8788 or news@teminandco.com.