BOULDER, CO (August 2, 2004) – Sirna Therapeutics, Inc. and Archemix Corp. announced that they have entered into an exclusive four-year process development, analytical development and manufacturing alliance for all of Archemix’s cGMP aptamers.

As part of this agreement, Sirna also granted Archemix a worldwide, perpetual, non-exclusive license to its intellectual property for the manufacture and commercialization of aptamers. In addition to payments for the manufacture of aptamers, Sirna will receive certain downstream consideration for the license granted to Archemix.

Sirna Therapeutics is using its proprietary technology and expertise in nucleic acids to develop a new class of nucleic acid-based therapeutics involving RNA interference. Archemix Corp. is a privately-held biopharmaceutical company based in Cambridge, Massachusetts.