Caliornia - The United States Patent and Trademark Office re-affirmed four patents (US 7,459,547, US 7,732,593, US 7,772,203 and US 7,750,144) known as the "Zamore Design Rule" patents following a re-examination requested by an anonymous third party, which previously issued as patents last year. The "Zamore Design Rule" patents are owned by the University of Massachusetts and are exclusively licensed to Silence Therapeutics. What makes these patents important is that they cover methods of promoting the incorporation of a desired guide strand into the RNA-Inducing Silencing Complex (RISC) through structural modifications, resulting in more effective and selective RNAi knockdown. By increasing the effectiveness of RNAi therapeutics, unwanted cellular activity and side effects are minimized.
More specifically, the "Zamore Design Rule" patents describe methods of enhancing the ability of an antisense strand of an RNAi agent to act as a guide strand; codify RNAi and siRNA agents for enhancing silencing of a target mRNA in an organism; and cover the composition of siRNA duplexes, pre-miRNA and shRNA in the process of RNA interference.
With this ruling, Silence Therapeutics will receive broad patent coverage for all structural and chemical approaches that incorporate bioinformatics pre-selection sequence algorithms in finding efficacious RNAi triggers. Any company using modified nucleotides for any purpose may have to be concerned that their process will infringe on Silence's patents.
Dr. Phillip Zamore, innovator of this process and professor of biochemistry and molecular pharmacology at the University of Massachusetts Medical School in Worcester, stated, "the initial granting of these patents was a significant milestone in the translation of the basic science of RNA interference into the real world of RNA therapeutics."
After a patent has been unsuccessfully challenged through re-examination, its value is considered higher. Knowing its proven value, companies such as Novartis are expressing interest in licensing the "Zamore Design Rule" patents.