Marina Biotech, Inc. a leading RNAi-based drug discovery and development company, announced that the Japanese Patent Office has issued patent application 2007-509522 covering its proprietary nucleic acid condensing and delivery peptide motif. This patent protects the peptide motif and its use with therapeutic nucleic acids, including siRNA, microRNA, meroduplex siRNA (3-stranded siRNA), single-stranded RNA and short-hairpin RNA (shRNA). This patent adds to the Company's global peptide-based delivery patent portfolio that includes nanoparticle forming peptides, peptide-siRNA conjugates, tissue targeting peptides and a Trp-cage peptide phage display library for selection of targeting ligands.

“The development of peptide-based delivery systems for therapeutic nucleic acids has been challenging due to the high concentration of nucleic acid necessary, and the large amount of peptide typically required, to achieve a gene knockdown event,” stated Barry Polisky, PhD, Chief Scientific Officer of Marina Biotech. “Our proprietary peptide technology has overcome many of these problems, and provides a means for creating peptide-nucleic acid nanoparticles having a predetermined charge (positive, negative or neutral) and size (less than 100 nanometers). Further, when combined with the company's DiLA2 delivery platform, a nanoparticle encapsulation in a DiLA2 liposome achieves greater gene knockdown per siRNA dose. That is, using a condensing peptide such as this, we can achieve gene knockdown with a lower concentration of siRNA.”

Marina Biotech's global portfolio includes 72 issued or allowed patents; 54 US patent applications; 135 foreign patent applications; and 8 PCT applications providing broad coverage for siRNAs, chemistry, delivery and gene targets.

“This patent issuance strengthens our delivery patent portfolio, and further validates our worldwide patent strategy to protect multiple novel and innovative technologies for the delivery of RNAi-based therapeutics,” stated J. Michael French, president and CEO of Marina Biotech. “This allowance significantly enhances the Company's comprehensive intellectual property portfolio covering key platform technologies including siRNA constructs, delivery and chemistry used for the development of RNAi-based therapeutics. We expect to see continued issuances in our patent estate.”

Marina Biotech is a biotechnology company, focused on the development and commercialization of therapeutic products based on RNA interference (RNAi). The Marina Biotech pipeline currently includes a clinical program in Familial Adenomatous Polyposis (a precancerous syndrome) and two preclinical programs -- in hepatocellular carcinoma and bladder cancer.