Oxford, UK – 23 May 2006: Oxford BioMedica (LSE: OXB), a leading gene therapy company, announced today that a Phase II trial of TroVax in patients with prostate cancer that is unresponsive to hormone therapy is open for recruitment. This is the first clinical trial of TroVax in this cancer type.

The Phase II trial in prostate cancer is being conducted at the Methodist Hospital in Houston, Texas, USA. The Principal Investigator for the trial is Dr Robert Amato. The trial is designed to enrol 24 men with hormone-refractory prostate cancer who have previously received chemotherapy or have refused chemotherapy and have progressive disease. The trial is open label and will have two arms (12 patients each) to assess the activity of TroVax alone versus TroVax alongside an approved treatment for prostate cancer, granulocyte macrophage-colony stimulating factor (GM-CSF).

The primary objectives of the trial are to evaluate the safety and synergies of the combination treatment, and to assess whether GM-CSF, which is known to increase white blood cell count and hence boost the immune system, increases the anti-cancer immune response stimulated by TroVax. Efficacy endpoints include objective response rate, progression-free survival, overall survival and changes in prostate-specific antigen (PSA) level, which is a recognised marker of disease status.

Prostate cancer is the leading cause of cancer in men. Localised radiotherapy or surgery is potentially curative for early-stage disease although many patients relapse and require hormone therapy. However, therapeutic options are limited when the cancer has progressed and no longer responds to hormone therapy, which is the setting for the Phase II trial of TroVax. Initial data from this trial are expected in the first half of 2007. According to Datamonitor, treatments for prostate cancer generated worldwide sales of $2.7 billion in 2004.

Commenting on the start of the Phase II trial in prostate cancer, Oxford BioMedica’s Chief Medical Officer, Dr Mike McDonald, said: “We are delighted that Dr Amato is supporting a Phase II trial of TroVax in prostate cancer. Given what we know of the product’s safety profile and the anti-cancer immune response that it stimulates, we are hopeful that TroVax can provide a new therapeutic option for patients with prostate cancer who have progressed despite hormone therapy and for whom there are few available treatments.”

Dr Robert Amato, Director of the Genitourinary Oncology Center at the Methodist Hospital said: “TroVax could provide a significant benefit to patients with hormone-refractory prostate cancer, particularly when administered with an effective immunostimulant such as GM-CSF. Our team at the Methodist Hospital has seen some intriguing clinical responses with TroVax from our trial in renal cell carcinoma and we are delighted to expand our collaboration with Oxford BioMedica into prostate cancer.”

Oxford BioMedica’s Chief Executive Officer, Professor Alan Kingsman added: “As we broaden and deepen the clinical development of TroVax, the value of our lead product candidate increases for potential partners.”

Clinical evaluation of TroVax is ongoing in renal cell carcinoma, colorectal cancer and now prostate cancer. Oxford BioMedica plans to start a Phase III trial in renal cell carcinoma in the second half of 2006. The Company recently secured a Special Protocol Assessment agreement with the FDA for this Phase III trial. An update on the clinical trials and development plan for TroVax will be released to coincide with TroVax presentations at the American Society of Clinical Oncology (ASCO) Annual Meeting, to be held on 2-6 June in Atlanta, Georgia, USA.

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For further information, please contact:

Oxford BioMedica plc:

Professor Alan Kingsman, Chief Executive

Tel: +44 (0)1865 783 000

City/Financial Enquiries:

Lisa Baderoon/ Mark Court/ Mary-Jane Johnson
Buchanan Communications

Tel: +44 (0)20 7466 5000

Scientific/Trade Press Enquiries:

Katja Stout/ Gemma Bradley

Northbank Communications

Tel: +44 (0)20 7886 8150

Notes to editors

1. Oxford BioMedica

Oxford BioMedica (LSE: OXB) is a biopharmaceutical company specialising in the development of novel gene-based therapeutics with a focus on oncology and neurotherapy. The Company was established in 1995 as a spin out from Oxford University, and is listed on the London Stock Exchange.

Oxford BioMedica has core expertise in gene delivery, as well as in-house clinical, regulatory and manufacturing know-how. In oncology, the pipeline includes two candidates in multiple Phase II trials, and a preclinical targeted antibody therapy in collaboration with Wyeth. A Phase III trial in renal cancer with TroVax, the lead cancer immunotherapy candidate, is expected to start in the second half of 2006. In neurotherapy, the Company’s lead product is a gene therapy for Parkinson’s disease, which is expected to enter clinical development in 2006, and four further preclinical candidates. The Company is underpinned by over 80 patent families, which represent one of the broadest patent estates in the field.

The Company has a staff of approximately 70 split between its main facilities in Oxford and its wholly owned subsidiary, BioMedica Inc, in San Diego, California. Oxford BioMedica has corporate collaborations with Wyeth, Intervet, Sigma-Aldrich, Viragen, MolMed, VIRxSYS and Kiadis; and has licensed technology to a number of companies including Merck & Co, Biogen Idec and Pfizer.

Further information is available at www.oxfordbiomedica.co.uk

2. TroVax^®

TroVax is Oxford BioMedica’s leading cancer immunotherapy product. It is designed specifically to stimulate an anti-cancer immune response and has potential application in most solid tumour types. TroVax targets the tumour antigen 5T4, which is broadly distributed throughout a wide range of solid tumours. The presence of 5T4 is correlated with poor prognosis. The product consists of a poxvirus (MVA) gene transfer system, which delivers the gene for 5T4 and stimulates a patient’s body to produce an anti-5T4 immune response. This immune response destroys tumour cells carrying the 5T4. TroVax has attracted external support from Cancer Research UK and the US National Cancer Institute. Over 100 patients have now been treated with TroVax in six clinical trials (collectively over 400 doses). The Company is targeting colorectal cancer and renal cell carcinoma (RCC) as lead indications for the development of TroVax. Renal cell carcinoma is an indication where TroVax might achieve a rapid route to product registration.

3. Prostate cancer

Prostate cancer is the leading cause of cancer in men. According to the American Cancer Society, an estimated 232,090 new cases of prostate cancer were diagnosed in the USA in 2005 and approximately 29,900 men die of this disease annually. The five-year survival rate of men with prostate cancer is 98%, although this falls to 34% for metastatic disease. Localised radiotherapy or surgery is potentially curative for early-stage disease although many patients relapse and require hormone therapy. According to Datamonitor, treatments for prostate cancer generated worldwide sales of $2.7 billion in 2004. However, therapeutic options are limited when the cancer has progressed and no longer responds to hormone therapy. Early detection is important, and it is recommended that men over the age of 50 have a prostate-specific antigen (PSA) blood test every year.