OXFORD BIOMEDICA PLC

At the 2^nd Annual Meeting of the American Society of Gene Therapy, the largest and most prestigious annual gathering of gene therapy professionals, held in Washington D.C., Oxford BioMedica scientists described preclinical data that has resulted in the Company's first product, MetXia-P450^TM, entering clinical development for the treatment of advanced breast cancer. The audience consisted of the leading professionals from around the world including representatives of all the major companies with active programmes in gene therapy.

A common strategy for the treatment of cancer is to administer cytotoxic (or cell killing) drugs in an attempt to destroy the tumour. Cyclophosphamide is one of a group of drugs that is taken by the patient in the form of an inactive prodrug. The prodrug travels through the body to the liver where enzymes convert it to the active, cytotoxic form. This approach affects the whole body and leads to the familiar adverse side effects of cancer chemotherapy because the cytotoxic drug destroys normal cells on its way from the liver to the tumour. In addition, because the activating enzymes are present only in the liver, high doses of prodrug must be given to achieve therapeutic levels of the cytotoxic drug at the tumour site. Often the therapeutic effect is compromised by the toxicity.

MetXia-P450 addresses these problems by delivering the gene (CYP2B6) directly to the tumour. Once incorporated into the genetic material of the tumour cells, this gene produces the liver enzyme that converts the cyclophosphamide pro-drug to its active form within the tumour. The aim is to achieve high concentrations of activated cyclophosphamide locally in the tumour while minimising circulating levels of the drug. It is anticipated that this will lead to substantially increased sensitivity of the tumour to the drug and to an ability to reduce the dose of cyclophosphamide, thereby reducing adverse side effects.

In a variety of preclinical models, described at the conference, the Company has shown that delivery of the human CYP2B6 gene to tumours, using MetXia-P450, does indeed increase their sensitivity to cyclophosphamide and leads to enhanced tumour cell killing. These data have provided the basis of submissions to the regulatory authorities for trials in breast cancer (BC1) and ovarian cancer (OC1). Initial results for the BC1 trial are expected to be available towards the end of the year, with OC1 results expected shortly afterwards.

Commenting on the presentation Chief Executive, Alan Kingsman said, "Oxford BioMedica's reputation for quality research is such that it is often called upon to present details of its broad technology base to prestigious meeting such as this. Presenting our preclinical data allows us to showcase the broad platform of technology that the Company has to offer to a wide audience of professionals in industry and academia. Already we are receiving enquiries from other technology-based as well as large multinational pharmaceutical companies to explore the application of our technology to their development programmes in gene therapy. Some of these enquiries have already progressed to the discussion of licensing terms between Oxford BioMedica and the various commercial concerns".

"The very high quality of the preclinical results that we have presented today was crucial in supporting our submission to GTAC for the approval of our clinical trial protocol for the treatment of breast cancer. While we await the trial results with eager anticipation, it must be remembered that efficacy in pre-clinical studies does not guarantee efficacy in man".

Notes to Editors 1. Oxford BioMedica: Established in 1995, specialises in the development and application of gene-based therapeutics using advanced gene delivery technologies for the treatment of disease in the areas of Oncology, Viral Infection, Neurobiology, Cardiovascular Disease and Genetic Deficiency. Oxford BioMedica plc was floated on the UK Alternative Investment Market of the London Stock Exchange in December 1996.