Silence Therapeutics Announces Positive Response by USPTO that Affirms Validity of Four Foundational RNAi Patents

Following a review requested by an anonymous third party during 2010, the USPTO has concluded that the reissued claims are patentable and has issued Notices of Intent to Issue Reexamination Certificates. The prior art cited in the reexaminations was unsuccessful in invalidating the patents.

The four patents (US 7,459,547, US 7,732,593, US 7,772,203 and US 7,750,144) form part of the foundational “Zamore Design Rule” patent families that disclose various efficacy-enhancing methods and structural elements for RNAi therapeutics. Silence has exclusively licensed three “Zamore Design Rule” patent families in their entirety for applications in the human healthcare field from the University of Massachusetts Medical School. The three patent families generally disclose methods of enhancing the silencing activity of RNAi agents through certain structural modifications. The claims associated with the reexaminations include coverage for methods of enhancing silencing of a pharmaceutical composition containing short interfering RNA (siRNA), micro RNA (miRNA), pre-miRNA or short hairpin RNA (shRNA) molecules.

Thomas Christély, Chief Executive Officer of Silence Therapeutics, said: “We are very pleased that the USPTO has reissued these four patents. This outcome sends a clear message regarding the strength of Silence’s intellectual property. We believe that there is significant value in the Zamore technology as a fundamental tool for the development and commercialisation of RNAi therapeutics with enhanced efficacy and will continue to work to translate this value into our own RNAi therapeutic pipeline.”