Boston Scientific Chief Financial Officer, Lawrence C. Best, Joins Archemix Corp. Board of Directors

Boston Scientific Chief Financial Officer, Lawrence C. Best,
Joins Archemix Corp. Board of Directors

 CAMBRIDGE, MA April 26, 2005 Archemix Corp., the privately-held
biopharmaceutical company focused on discovering and developing aptamer-based
therapeutics, announced today that Lawrence C. Best has been appointed to the
Companys Board of Directors.  In addition to his responsibilities as a
Board member, Mr. Best qualifies as an Audit Committee Financial Expert in
accordance with Regulation S-K 401(h) and the rules implementing Section 407 of
the Sarbanes-Oxley Act.

Mr. Best currently serves as Executive
Vice President and Chief Financial Officer of Boston Scientific Corporation. He
brings more than 30 years of financial experience to Archemix.  Prior to
his work with Boston Scientific, Mr. Best was a partner in the accounting firm
of Ernst & Young, where he specialized in serving multinational companies in
the high technology and life sciences fields. He served a two-year fellowship at
the Securities and Exchange Commission from 1979 to 1981 and a one-year term as
a White House-appointed Presidential Exchange Executive in Washington. Mr. Best is also a Director and Audit
Committee Financial Expert for Biogen Idec and Haemonetics Corporation.

We are
privileged to have someone of Larrys experience and knowledge join our Board,
commented Dr. Errol De Souza, Chief Executive Officer of Archemix. “Larry brings
an impressive record of financial expertise and strategic management and has
been a key member of the Boston Scientific executive team that is credited with
building one of the foremost companies in the medical device industry.
Dr. De Souza also stated that filling the role of financial expert is an
important step for Archemix as we continue to evolve our Board to meet the
requirements of a public company.

Archemix is at an exciting stage of its development,
said Mr. Best. The Companys aptamers have the potential to bring forth a new
class of therapeutics for the treatment of acute and chronic diseases. I look
forward to contributing to Archemix as the company strives to meet its strategic
initiatives and develops its portfolio of aptamer therapeutics.

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 complemented 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.