USPTO issues patent covering methods for enhancing RNA silencing activity of RNAi agents

Silence Therapeutics plc (AIM: SLN) ("Silence" or the "Company") announces the issuance of United States patent 7,732,593, titled Methods and Compositions For Controlling Efficacy of RNA Silencing, by the United States Patent and Trademark Office (USPTO).  The issued patent, which is based on the seminal research of Phillip D. Zamore, Ph.D., Howard Hughes Medical Institute Investigator, the Gretchen Stone Cook Chair of Biomedical Sciences, and Professor of Biochemistry & Molecular Pharmacology at University of Massachusetts Medical School, generally claims methods of enhancing the RNA silencing activity of RNA interference (RNAi) agents through certain structural modifications.  The issued claims not only cover enhancing the efficacy of silencing gene expression using short interfering RNA (siRNA) but also include specific claims directed to micro RNA (miRNA), pre-miRNA, and short hairpin RNA (shRNA).  

Silence owns exclusive licenses to three Zamore patent families from the University of Massachusetts Medical School, where Zamore is the co-director of the RNA Therapeutics Institute.  These patent families disclose various efficacy-enhancing methods and structural elements for RNAi therapeutics, informally known as the "Zamore design rules" and based on Dr. Zamore's work at UMass.  The company expects additional U.S. patent issuances related to this Zamore intellectual property portfolio in the coming months.

"Today's patent issuance continues to highlight the powerful synergies created by the combined assets of Silence and Intradigm.  In this case, the exclusive licenses originally owned by Intradigm to the Zamore patent families have provided Silence with valuable structural modification technology that will contribute to further strengthening and expanding the company's comprehensive RNAi therapeutic platform," stated Philip Haworth, Ph.D., chief executive officer of Silence Therapeutics.  "There is a growing consensus within the industry regarding the important role of optimized siRNA structure for developing more potent next generation RNAi therapeutics.  With exclusive access to the industry leading technology in this area, Silence continues to position itself as the partner-of-choice for pharmaceutical companies with interest in the RNAi space."

Silence Therapeutics is executing a proactive strategy to continue to build and strengthen a diverse and competitive intellectual property portfolio that provides the company and its partners with a strong proprietary position in the RNAi therapeutics space.  The company believes that it will continue to make significant progress in these efforts throughout 2010 as it expects a number of additional valuable RNAi patents to be issued in both the United States and Europe during the year.  This consistent and meaningful IP portfolio growth reinforces Silence's belief that the company can sustain its position as a preferred partner in RNAi therapeutics.  At present, Silence's global patent portfolio contains issued patents and pending applications covering strategic areas of RNAi therapeutic development including multiple proprietary siRNA delivery technologies, potent siRNA sequences specific for high-value disease targets and key RNAi sequence and chemical modifications.