On Mar. 6, 2014, Merck announced that it had sold Sirna to Alnylam for $175 million. Sirna, orginally known as Ribozyme Pharma was founded in Boulder in 1992 with a focus on the broad potential of ribozymes for use in the development of human therapeutics and other areas and in the identification of gene function.

Sirna was acquired by Merck $1.1 billion in cash in 2007.