Robert B. Stein, M.D., Ph.D., Joins Archemix Board of Directors

CAMBRIDGE, Mass.
April 3, 2007

Archemix Corp. announced today that Robert B. Stein, M.D., Ph.D., has been appointed to the company's Board of Directors.

Dr. Stein brings to Archemix over 25 years of experience in research and development and business roles with pharmaceutical and biotechnology companies. From 2003 through 2006, he served as the President of Roche Palo Alto. Prior to joining Roche, Dr. Stein was the President and Chief Scientific Officer of Incyte Corporation. Dr. Stein's career also includes significant positions at companies including Merck & Co., Ligand Pharmaceuticals, and DuPont Merck Pharmaceutical Company. In addition to the business leadership he has brought to his various roles, Dr. Stein has also participated in the discovery and development of six marketed medicines.

"We are privileged to have such a knowledgeable industry leader as Dr. Stein join our Board," commented Dr. Errol De Souza, President and Chief Executive Officer of Archemix. "Dr. Stein's extensive scientific and operational expertise makes him a valuable addition to our Board of Directors. Further, his pharmaceutical and drug development and regulatory expertise will serve Archemix well as we continue to rapidly advance our aptamer product pipeline."

"Archemix is at an exciting stage of its development," said Dr. Stein. "The company's work with aptamers is demonstrating their potential as therapeutics for the treatment of acute and chronic diseases. Archemix holds a dominant intellectual property position, placing it at the forefront of the development of therapeutic aptamers. I look forward to lending my experience and perspective to the management team at Archemix."

After receiving undergraduate degrees in biology and chemistry from Indiana University, Dr. Stein studied at Duke University, where he received a Ph.D. in physiology and pharmacology and an M.D. He completed residency training and is board certified in anatomic and clinical pathology. He joined the pharmaceutical industry in 1982 at Merck Laboratories.

About Aptamers
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. Aptamers combine the optimal characteristics of small molecules and antibodies, including high specificity and affinity, chemical stability, low 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.

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 prevention and treatment of human disease. Because of their unique properties and proven efficacy, aptamers offer an alternative to biologics and small molecules in numerous applications and offer the potential to be a major class of drugs for the treatment of unmet medical needs.

Archemix's aptamer expertise is complemented by a robust 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 pre-clinical and clinical drug development. Further information on Archemix can be found at www.archemix.com.

For more information about Archemix or aptamers, or to speak with Dr. De Souza, please contact Davia Temin or Suzanne Oaks of Temin and Company at 212-588-8788 or news@teminandco.com.