CAMBRIDGE, Mass. & OSAKA, Japan
June 11, 2007

Archemix Corp. ("Archemix") and Takeda Pharmaceutical Company Limited ("Takeda") announced today that both parties have signed a multi-year, three target agreement that focuses on the discovery, development and commercialization of first-in-class aptamer-based therapeutics.

Under the agreement, Archemix will receive an upfront payment of $6 million from Takeda to discover and generate product candidates to three disease-associated targets identified by Takeda, and Takeda will be granted exclusive, worldwide rights for research, development, manufacturing and commercialization for any resulting aptamer-based products. Archemix will also receive committed research funding and research and clinical development milestone payments for each target selected for therapeutic development. In addition, Archemix will earn royalties and milestones on worldwide sales of the developed aptamers commercialized by Takeda. Detailed financial terms were not disclosed.

"Our alliance with Takeda is the sixth major partnership we have formed within the past year and is a major step in the continued validation of aptamer therapeutics," said Errol De Souza, Ph.D., President and CEO, Archemix. "Takeda is an excellent partner for Archemix and this collaboration is a key component of successfully implementing our strategy of forming collaborations with multi-national pharmaceutical companies to rapidly advance aptamer programs into clinical development."

"We are very impressed with Archemix' track record of success in creating therapeutic aptamers," said Dr. Shigenori Ohkawa, General Manager of Pharmaceutical Research Division, Takeda. "Archemix is the leader in the discovery of aptamer therapeutics and we believe that, as a class, aptamers have the potential to create a new paradigm of treatments in a broad spectrum of diseases, and we believe this collaboration will surely contribute to enhancing our R&D pipeline as source for future growth of Takeda."

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.

About Archemix
Archemix Corp. is a privately-held biopharmaceutical company developing aptamers as a class of directed therapeutics for the prevention and treatment of human disease. The company is leveraging its proprietary drug discovery technology to fuel the growth of its development portfolio, which is primarily focused on acute cardiovascular and hematology diseases and cancer. Archemix's broad product pipeline, being developed both by the company as well as its licensees, includes multiple investigational compounds at various stages of development several of which are moving into advanced clinical trials. Archemix's lead proprietary product, ARC1779, a selective platelet inhibitor, is anticipated to start Phase IIa clinical trials before the end of 2007. Archemix' leadership position in intellectual property, technology and expertise relating to aptamers has enabled it to form numerous collaborations with biotechnology and pharmaceutical collaborators, including Merck Serono, Pfizer Inc., Elan Pharma, Nuvelo, Inc., Antisoma plc., and Regado Biosciences. For more information, please visit www.archemix.com.

About Takeda
Located in Osaka, Japan, Takeda is a research-based global company with its main focus on pharmaceuticals. As the largest pharmaceutical company in Japan and one of the global leaders of the industry, Takeda is committed to striving toward better health for individuals and progress in medicine by developing superior pharmaceutical products. Takeda is actively dedicated to enhance its pipeline for future growth through alliance as well as in-house R&D activities. Additional information about Takeda is available through its corporate website, www.takeda.com.