OXFORD BIOMEDICA AND SIGMA-ALDRICH WIN KEY RULING IN OPEN BIOYSTEMS PATENT INFRINGEMENT DISPUTE

Oxford, UK and St. Louis, Mo - 26 October 2007: Oxford BioMedica (LSE: OXB), a leading gene therapy company, and Sigma-Aldrich (NASDAQ:SIAL), a life science company dedicated to providing state-of-the-art chemical and biotechnology products to the world's researchers, announced today that they received a key order confirming the strength and validity of intellectual property owned by Oxford BioMedica and licensed exclusively in the research field to Sigma-Aldrich. The ruling was part of the construction of patent claim terms in the patent infringement suit brought against Open Biosystems, Inc. The lawsuit, which is pending in the U.S. District Court for the Eastern District of Missouri, alleges that Open Biosystems infringes U.S. Patent Nos. 6,924,123 and 7,056,699 entitled Lentiviral LTR Deleted Vector, which are owned by Oxford BioMedica and exclusively licensed to Sigma-Aldrich for research use, by selling, among other products, Open Biosystems' Lentiviral shRNAmir Library. In his order U.S. District Judge Charles A. Shaw concluded "that the constructions of the disputed terms and phrases proposed by plaintiff are correct."

David Smoller, President, Research Biotechnology Business Unit of Sigma-Aldrich said: "We are gratified and very pleased that the Court has adopted Sigma's and Oxford's definitions of all disputed claim terms in this case. This Order reinforces Sigma's belief that the Oxford BioMedica patents are "core patents" in the RNA-interference field, and validates Sigma's decision to license these patents and make other significant investments in creating a comprehensive portfolio of intellectual property that allows our customers to use this extraordinary technology without fear of interference or unfair competition. We will continue to vigorously defend Oxford's extraordinary inventions and Sigma's investment in this valuable intellectual property."

Peter Nolan, SVP Commercial Development at Oxford BioMedica said: "I am delighted with this Order, which validates Oxford BioMedica's patents and strengthens our position in this field." Oxford BioMedica's LentiVector^® system has broad applications in gene delivery and can be used to deliver shRNA-encoding DNA to cells to enable RNA Interference (RNAi) experiments. Based on discoveries by Oxford BioMedica's Drs. Susan and Alan Kingsman and others, scientists are now able to safely use modified lentiviruses as vectors, which enable RNAi to be effectively utilised as a research tool to unlock the secrets of the genetic code. As stated in the Court's Order, the viral vector developed by the Kingsmans is expected to be useful as a "smart bomb" to safely "deliver new genetic material into specific cells, such as cells that do not divide or that divide slowly," giving the delivery of genes that produce dopamine into a Parkinson's disease patient's brain cells, as an example.

"Sigma believes this technology holds huge promise to better understand the human genome and to, ultimately, help devise techniques to defeat and diminish longstanding misery'causing diseases such as Parkinson's and Alzheimer's," said Smoller.

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