Isis Pharmaceuticals, Inc and Alnylam Pharmaceuticals, Inc announced that the United States Patent and Trademark Office (US PTO) has allowed an Isis patent application that further expands the scope of the 'Crooke' patent estate. The newly allowed patent broadly covers methods of cleaving a target RNA via a double-stranded ribonuclease mechanism, including the RNAi mechanism, with chemically modified, single-stranded RNA-containing drugs. Last year, Isis was awarded patents covering the compositions and methods of treating patients with a double-stranded or a single-stranded RNA-containing compounds, including double-stranded small interfering RNA (siRNA), which further strengthened Isis' broadly applicable intellectual property estate covering RNA-based drug discovery and development.

Isis' Crooke patent estate is a family of patents stemming from the innovative research of Stanley Crooke, and others at Isis to identify and design RNA molecules that utilize numerous different antisense mechanisms. Isis continues this research effort by utilizing its RNA expertise with its broad oligonucleotide medicinal chemistry endeavours to design drugs that are optimal to exploit each different mechanism and have attractive pharmaceutical properties. The Crooke patents are part of Isis' patent estate, which includes more than 1,600 issued patents worldwide and broadly covers the design and use of RNA-containing drugs. The Crooke patent estate is owned by Isis and licensed co-exclusively to Alnylam for RNAi drugs, and exclusively licensed to Regulus Therapeutics for microRNA-based drugs.

"The Crooke patents are a product of our pioneering efforts to investigate and understand the mechanisms by which antisense drugs work and to create attractive antisense drugs that exploit those mechanisms. The Crooke patents have evolved into a formidable set of intellectual property that cover our innovative advances to develop chemically modified antisense drugs optimized for each individual antisense mechanism. This patent estate provides us with broad protection against competitors who are developing RNA-based drugs," said Stanley Crooke, chairman and chief executive officer of Isis. "When combined with our existing patents, this new allowance extends our coverage for the development of single-stranded RNA-containing compounds that work through the RNAi pathway. Furthermore, the timing of this allowance comes on the heels of our newly announced, single-stranded RNAi technology collaboration with our partner Alnylam. We believe that with our experience in developing powerful single-stranded antisense drugs and Alnylam's expertise in the field of RNAi therapeutics, we can advance single-stranded RNAi technology to create innovative new drugs with different and potentially enhanced pharmaceutical properties that act through the RNAi mechanism."

"We are pleased with the decision by the USPTO to allow this additional patent in the Crooke patent family for ssRNAi technology. There should be no doubt that the pioneering efforts at Isis have been at the forefront of new discovery for all oligonucleotide therapeutic classes," said John Maraganore, chief executive officer of Alnylam. "As we continue our primary focus on double-stranded siRNAs, we believe that ssRNAi technology has significant potential to advance the field of RNA therapeutics broadly. While there's more to do, we are excited to combine our expertise with Isis' in advancing this promising initiative."

Issued patents in the Crooke estate already include US Patent No 5,898,031 covering RNA-containing therapeutic compounds, and US Patent No. 6,107,094 covering methods of using these compounds to interfere with target RNA function, including not only interrupting protein production with single-stranded and double-stranded (siRNA) antisense compounds but also targeting other RNAs, such as microRNAs. US Patent No. 7,432,250 covering methods of treating patients by administering siRNA or single-stranded RNA-like compounds; and claims in US Patent No. 7,432,249 cover pharmaceutical compositions containing single-stranded RNA-like compounds. The newly allowed claims in US Patent Application No. 10/281,349 cover methods of cleaving a target mRNA by a double-stranded ribonuclease (e.g. RNAi) mechanism by contacting the target mRNA with a chemically modified, single-stranded, RNA-containing therapeutic compound.

These claims further strengthen Isis' broadly applicable intellectual property estate covering RNA-based drug discovery, development, and therapeutic uses.

Following a Notice of Allowance, the process resulting in final issuance of a patent involves several administrative steps that are typically completed within a year.

Alnylam is a biopharmaceutical company developing novel therapeutics based on RNA interference, or RNAi.

Isis is exploiting its expertise in RNA to discover and develop novel drugs for its product pipeline and for its partners.