Sirna Therapeutics granted new UK patents

Jul 12 2005

Sirna Therapeutics has announced that the United Kingdom (UK) Patent Office has granted the Company two additional short interfering RNA (siRNA) target patents. The first patent covers any siRNA with one or more chemical modifications targeting Vascular Endothelial Growth Factor (VEGF).

The second patent covers any chemically modified siRNA targeting Hepatitis C Virus (HCV). The claims of these patents are not limited to any specific siRNA sequence, but broadly cover any siRNA sequence used against the entire targeted gene. Further, the claims of these patents are not limited to any specific type of chemical modification or structure, but broadly cover any chemical modification that can be made to the siRNA and cover blunt-ended siRNAs and those with one or more nucleotide overhangs. Sirna has filed over 100 patents worldwide for the broad coverage of siRNAs targeting disease causing genes and viruses. The issuance of these patents further strengthens Sirna's intellectual property estate as well as its discovery programs as the Company is currently pursuing development programs in HCV and age-related macular degeneration (AMD) targeting the VEGF pathway.

Sirna President and Chief Executive Officer, Howard W. Robin stated, "Both patents stem from the internal scientific achievements at Sirna and provide further proof of Sirna's superior RNA chemistry and biology expertise. We believe that the issuance of these broad patents in the UK are indicative of future patent grants we expect to receive in the United States and worldwide. These patents now join over 40 issued patents covering RNA chemistry and biology and serve to demonstrate Sirna's leadership position in the field."

The first patent titled " RNA Interference Mediated Inhibition Of Vascular Endothelial Growth Factor And Vascular Endothelial Growth Factor Receptor Gene Expression Using Short Interfering Nucleic Acid (siNA)" (UK Patent No. GB2406569) covers any chemically modified siRNA targeting VEGF. The claims in this patent are not limited to any specific siRNA sequence but broadly cover any siRNA used against the entire targeted gene. This is the first patent issued covering broad claims for an siRNA targeting the VEGF cytokine. The Company believes that the issuance of this patent together with the previously granted patent covering VEGF receptor (UK Patent No. GB2396864) provides Sirna a dominant position on the use of siRNAs targeting the VEGF pathway, especially as they relate to the development of siRNAs for the treatment of diseases such as AMD.

The second patent titled "RNA Interference Mediated Inhibition of Hepatitis C Virus (HCV) Gene Expression Using Short Interfering Nucleic Acid (siNA)" (UK Patent No. GB2397062) covers siRNAs with one or more chemical modifications targeting HCV. Again, the claims of this patent are not limited to any specific siRNA sequence but broadly cover any siRNA used against the entire viral genome. The claims also cover siRNAs targeting the plus and the minus strands of the virus and the genes encoded by the viral genome. This is the first patent issued covering broad claims for an siRNA targeting HCV.

The issuance of these two patents follows two prior patents granted to Sirna earlier this year in the UK. They include a patent covering the chemical and structural modifications of siRNAs necessary for the creation of viable siRNA-based therapeutics. The chemical modifications covered in this patent are essential for the stability, potency and duration of action of siRNA therapeutics as unmodified siRNAs degrade rapidly in vivo. The second patent granted earlier this year covers chemically modified siRNAs targeting a receptor of VEGF.

Sirna has filed enabling patents for over 100 important mammalian disease targets including: alpha-synuclein (Parkinson's disease), HBV (hepatitis B), HCV (hepatitis C), HD (Huntington's disease), HIV (human immunodeficiency virus), HR (hairless gene), IL-4, IL-13, IL-4 Receptors, IL-13 Receptors (asthma, respiratory diseases), NOGO & NOGO Receptors (spinal cord injury), PTP-1B (diabetes, obesity) and VEGF (angiogenesis, AMD, diabetic retinopathy, cancer, kidney disease).