Cambridge, MA - December 23, 2008 - Archemix Corp. and GlaxoSmithKline (GSK) today announced a worldwide strategic alliance to discover, develop and commercialise aptamer therapeutics to treat inflammatory diseases, such as rheumatoid arthritis and inflammatory bowel disease. Aptamers are synthesized oligonucleotides, or short nucleic acid sequences, that bind to proteins with high affinity and specificity.

The alliance leverages Archemix’s unique expertise and intellectual property position in the discovery and development of aptamer therapeutics and provides GSK with an option to license product candidates directed at seven different aptamer targets with relevance in inflammatory disease.

Under the terms of the agreement, Archemix will receive $27.5 million in upfront payments from GSK, including a $6.5 million equity investment by GSK in the company. Archemix could also be eligible to receive up to $200 million in development, regulatory and sales milestone payments for each of the seven aptamer therapeutics which may be discovered and developed as part of the alliance. Archemix would also receive tiered royalties up to lower double digits on worldwide sales of products that may result from the alliance.

“We are very excited about this collaboration with GSK. GSK is an outstanding partner with leadership and expertise in inflammation, and we look forward to expanding our efforts in inflammation where aptamers could offer novel options to treat disease,” said Errol DeSouza, Ph.D., President and Chief Executive Officer of Archemix. “This is another step forward in our strategy to leverage our intellectual property estate together with our significant internal capabilities in order to develop aptamers for a variety of therapeutic areas with key partners who are experts in their field.”

Archemix will be responsible for the discovery and development of the aptamer therapeutics through completion of clinical proof of mechanism, unless GSK chooses to exercise its option earlier. After exercise of the option, GSK will have an exclusive license to drug product candidates developed under each programme by Archemix for the relevant aptamer target for further development and commercialisation on a worldwide basis. Archemix will have the right to further develop and commercialise any aptamer therapeutics which GSK chooses not to develop or commercialise.

"This innovative multi-target drug-discovery deal is an important extension of our externalisation strategy and provides GSK with an outstanding opportunity to work with the world leader in aptamer discovery and development," said Jose Carlos Gutierrez-Ramos, PhD., Senior Vice President and Head of the Immuno-Inflammation Centre of Excellence for Drug Discovery in GSK. "The application of aptamers with their unique properties is an exciting opportunity that holds enormous potential for the treatment of many devastating diseases of the immune system."

About Aptamers
Aptamers are synthetically-derived oligonucleotides, or short nucleic acid sequences, that bind to protein targets with high affinity and specificity and can be designed to have a specified duration of action. Aptamers represent an emerging class of potential therapeutic agents that Archemix believes may have broad application to treat a variety of human diseases.

About Archemix
Archemix is a biotechnology company focused on discovering, developing and commercialising aptamer therapeutics. Using Archemix’s processes for discovering aptamers, which are protected by its broad patent portfolio, Archemix is developing aptamer product candidates for rare haematological diseases. In addition, Archemix has licensed its intellectual property to third parties to develop their own aptamer product candidates in other areas. Currently, Archemix’s licensees are evaluating five different aptamer product candidates in human clinical trials; two in Phase 2 and three in Phase 1. Archemix has additional partnerships with several pharmaceutical and biotechnology companies, including Merck Serono, Pfizer, Takeda, Eli Lilly and Isis Pharmaceuticals.

On November 18, 2008, Archemix announced that it had entered into a merger agreement with NitroMed, Inc., (NASDAQ: NTMD) pursuant to which Archemix has agreed to merge with NitroMed in an all-share transaction. The merger is subject to approval by Archemix's and NitroMed's shareholders, consummation of the sale of NitroMed's BiDil and BiDil XR drug business and other customary closing conditions. As a result of the $27.5 million in upfront payments received by Archemix from GSK, Archemix now estimates that cash and cash equivalents for the combined company at the closing of the merger will be approximately $78-88 million.

About GlaxoSmithKline

GlaxoSmithKline - one of the world’s leading research-based pharmaceutical and healthcare companies – is committed to improving the quality of human life by enabling people to do more, feel better and live longer. For company information, visit GlaxoSmithKline at www.gsk.com.