Isis Pharmaceuticals Inc has filed a patent infringement lawsuit against Sequitur Inc, Massachusetts, in United States District Court, Southern District of California. The lawsuit alleges infringement of U.S. Patent Number 6,001,653, a key patent in Isis' functional genomics suite of patents, which the company believes is utilized by Sequitur's Antisense Functional Genomics Program. Isis' functional genomics suite of patents broadly covers the use of antisense inhibitors for gene functionalization and target validation. A key component of this patent suite is the use of the RNase H mechanism of action. RNase H is the most common and potent mechanism of action employed by antisense when used as a functional genomics tool. Antisense is being widely used throughout the pharmaceutical and biotechnology industry for determining the biological role of genes.

"Our functional genomics suite of patents is a highly valuable asset to the company, and a result of more than a decade of invention and consolidation of intellectual property in the field of antisense. We are actively protecting these interests and are escalating efforts to use our intellectual property to attract partners, develop new collaborations and generate value for our shareholders," said B. Lynne Parshall, Isis' Executive Vice President and CFO. "We believe that companies performing antisense-based functional genomics activities are employing technologies covered by Isis' patent estate. We would welcome such companies as new collaborators, as our goal from the onset has been to lead the industry into antisense technology."

Isis' intellectual property position has been further strengthened by the U.S. Patent and Trademark Office's (PTO) issuance of a notice of intent to issue a Reexamination Certificate in the reexamination of U.S. Patent Number 6,001,653. Through that notice, the PTO confirmed for a second time the patentability of screening methods to identify effective antisense inhibitors, which use human RNase H1. Human RNase H1 is a naturally occurring cellular enzyme that cleaves the RNA portion of an RNA/DNA duplex, such as that formed when an antisense inhibitor binds to RNA.

"Since Isis' inception, our strategy has been to protect and enhance the use of antisense technology based on high-quality and profuse scientific invention," said Ms. Parshall. "We look forward to supporting and extending the use of antisense in target validation and generating revenues from licensing and collaborative activities."

Isis is providing custom gene functionalization and target validation services to pharmaceutical and biotechnology companies through its GeneTrove division. Technology licenses are also available to industry and academic researchers.

Isis' functional genomics suite of patents covers every phase of the application of RNA/DNA oligonucleotides, or antisense inhibitors, in gene functionalization and target validation, including: chemistries; antisense inhibitor designs called "motifs;" methods of use of antisense inhibitors; and mechanisms of action by which antisense inhibitors inactivate an RNA target. The functional genomics suite is comprised of approximately 50 patents, and represents a subset of Isis' overall intellectual property estate of nearly 800 owned or exclusively licensed patents covering RNA-based drug discovery and development.