Archemix Announces Milestone Achievement

Archemix Announces Milestone Achievement with Candidate Selection
by Eyetech as Part of Broad Collaboration to Discover and Develop Therapeutic Aptamers for Ophthalmology

 CAMBRIDGE, Mass., June 22 /PRNewswire/ — Archemix Corp. announced today
that Eyetech Pharmaceuticals, Inc. has formally selected and nominated its
first pre-clinical candidate pursuant to the parties’ collaboration agreement,
which was signed in 2004.

The pre-clinical candidate selected by Eyetech is an aptamer directed
against the target Platelet Derived Growth Factor-B (PDGF-B) for potential use
in neovascular age-related macular degeneration (neovascular AMD). In addition
to uses as a single agent, pre-clinical studies have also demonstrated that
aptamers directed against PDGF-B may provide additional benefit when used in
combination with Macugen(R) (pegaptanib sodium injection) for neovascular AMD.
In conjunction with this milestone, Archemix received an undisclosed payment
from Eyetech.

“Eyetech is pleased to announce that a candidate has been selected,”
stated Dr. David Guyer, Chief Executive Officer of Eyetech Pharmaceuticals.
“The speed with which we were able to select this candidate is indicative of
the quality of our collaboration and the science behind it. We view this
selection as an important step in building and deepening our product pipeline.
The use of combination therapy may represent the future direction of
ophthalmic treatment, and the opportunity to test an anti-PDGF aptamer with
Macugen places us on the cutting edge of this potential new paradigm of

“For Archemix, this candidate milestone demonstrates the value of our
expertise in therapeutic aptamers and our commitment to this collaboration,”
stated Dr. Errol De Souza, President and Chief Executive Officer of Archemix.
“The selection of a development candidate in less than one year after the
agreement was signed shows that our proprietary selection methods and know-how
translate into rapid discovery of high quality drug candidates. We look
forward to Eyetech using their extensive expertise to develop this and other
candidates that come out of this collaboration.”

Eyetech’s compound Macugen is being marketed with Pfizer Inc for the
treatment of all types of the neovascular AMD, the leading cause of
irreversible vision loss in developed countries in people over 60 years of
age. In addition, Eyetech and Pfizer are conducting a Phase 2 clinical trial
for the use of Macugen for the treatment of diabetic macular edema (DME), a
leading cause of blindness in younger people. Macugen is also being studied
for other indications including retinal vein occlusion.

About Aptamers
Aptamers are single-stranded nucleic acids that form well-defined three-dimensional shapes,
binding target molecules in a manner conceptually similar
to antibodies. Aptamers have a number of desirable characteristics for use as
therapeutics, including clinically demonstrated biological efficacy, high
specificity and affinity, and excellent pharmacokinetic properties.

About Archemix
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 pre-clinical and clinical drug development. Further
information about Archemix can be found at

For further information or to speak with Dr. Errol De Souza, please
contact Davia Temin of Temin and Company at 212-588-8788 or