FOR IMMEDIATE RELEASE

SIGMA-ALDRICH, OXFORD BIOMEDICA AND OPEN BIOSYSTEMS SETTLE PATENT DISPUTE OVER USE OF LENTIVECTOR TECHNOLOGY IN RESEARCH REAGENTS

Huntsville, AL, March 7, 2008, -- Sigma-Aldrich (Nasdaq: SIAL), Oxford BioMedica (LSE: OXB) and Open Biosystems, Inc., a privately held corporation, have jointly announced a confidential settlement of their patent litigation.  Sigma-Aldrich and Oxford BioMedica agreed to dismiss the lawsuit brought against Open Biosystems. Open Biosystems agreed to dismiss its counterclaims in the lawsuit. As part of the settlement Open Biosystems will acquire certain license rights under the Oxford BioMedica patents for use of the LentiVector technology in research activities. Other details of the agreement have not been disclosed

About Sigma-Aldrich: Sigma-Aldrich is a leading Life Science and High Technology company. Its biochemical and organic chemical products and kits are used in scientific and genomic research, biotechnology, pharmaceutical development, the diagnosis of disease and as key components in pharmaceutical and other high technology manufacturing. The Company has customers in life science companies, university and government institutions, hospitals, and in industry. Over one million scientists and technologists use its products. Sigma-Aldrich operates in 36 countries and has 7,900 employees providing excellent service worldwide. Sigma-Aldrich is committed to Accelerating Customer Success through Leadership in Life Science, High Technology and Service.

About Oxford BioMedica plc:  Oxford BioMedica (LSE: OXB) is a biopharmaceutical company specializing in cancer immunotherapy and gene-based therapies. The Company was established in 1995, as a spin-out from OxfordUniversity, and is listed on the London Stock Exchange. The Company has a platform of gene delivery technologies, which are based on highly engineered viral systems. Its lead product candidate is TroVax®, an immunotherapy for multiple solid cancers, which is licensed to sanofi-aventis for global development and commercialization. TroVax is in Phase III development. Oxford BioMedica has three other products in clinical development, including ProSavin®, a novel gene-based treatment for Parkinson’s disease, in a Phase I/II trial. The Company is underpinned by over 80 patent families, which represent one of the broadest patent estates in the field.

About LentiVector® technology: Oxford BioMedica's LentiVector technology represents one of the most advanced gene delivery systems currently available. The technology is protected by multiple patents that cover the use of highly engineered lentiviruses as vectors for gene delivery. The LentiVector system has been shown to achieve safe and long-term gene transfer to a broad range of dividing and non-dividing cell types, including neurons and retinal cells, in a stable and efficient fashion. Licensed users of the technology include Biogen Idec, GlaxoSmithKline, Merck & Co and Pfizer.
 
About Open Biosystems: Open Biosystems, Inc. develops, manufactures and markets genomic research tools to scientists and researchers in corporate, academic and government laboratories. These research tools provide investigators with standardized high-quality genes, RNAi and antibodies for interrogating gene function in relation to oncology, neuroscience and metabolic disorders. Founded in 2001, Open Biosystems is headquartered in Huntsville, Alabama.

Contacts:
Troy Moore
Open Biosystems Inc.
email: troy.moore@openbiosystems.com

Cautionary Statement: This release contains forward-looking statements relating to future performance, goals, strategic actions and initiatives and similar intentions and beliefs and other statements regarding the Companies' expectations, goals, beliefs, intentions and the like, which involve assumptions regarding the Companies' operations and conditions in the markets the Companies serve. The Companies do not undertake any obligation to update these forward-looking statements.