Objections to Kreutzer-Limmer patent by Sirna Therapeutics accepted by the European Patent Office

Sirna Therapeutics has announced that its objections to the Kreutzer-Limmer patent in Europe were accepted by the European Patent Office, resulting in both a significant narrowing of the patent claims and substantial limitations on the commercial utility of that patent.

"We contended from the very beginning that the Kreutzer-Limmer patent would not stand up to scientific and legal scrutiny and that its true commercial and scientific value in the field of RNA medicines has been miscast and misunderstood," stated Howard W. Robin, President and Chief Executive Officer of Sirna Therapeutics. "We will continue to oppose unsubstantiated patent claims while growing our own intellectual property estate to seek to ensure that we have the freedom to advance both our own and our partners' RNAi-based therapies through the clinic and into the market."

European patent No: EP1144623B1 (the Kreutzer-Limmer patent), which was opposed by Sirna, AstraZeneca PLC, Atugen (SR Pharma PLC), Janssen Pharmaceutica N.V., and sanofi-aventis, was significantly narrowed and now only covers methods of making and using double stranded RNA with lengths and structures of limited usefulness as RNAi-based therapeutics.

"The claims of the Kreutzer-Limmer patent as granted are now limited to chemical structures, that in our experience, are obsolete and essentially ineffective as viable RNAi-based therapeutics," stated Bharat Chowrira, Ph.D., J.D. Chief Patent Counsel of Sirna Therapeutics. "We believe, therefore, that this patent has no impact on our current or future programs, and perhaps more importantly, that it does not provide any meaningful intellectual property protection in the field of RNAi-based therapeutics."

Sirna believes that its issued and pending patents in siRNA design, chemistry, synthesis, delivery and manufacturing together with its target patents and microRNA patents, give the company a dominant intellectual property portfolio in the field of RNAi-based therapeutics.