Second TroVax Phase I/II trial results presented at the 94^th annual meeting of the American Association for Cancer Research

Oxford, UK: 14 July 2003 - Oxford BioMedica announced today that it is presenting new clinical data on the Company’s lead cancer product, TroVax^®, at the American Association for Cancer Research (AACR) Annual Meeting in Washington, DC. The results are being presented by Dr. Richard Harrop, Principal Scientist at Oxford BioMedica. Following on from the earlier Phase I/II trial in colorectal cancer patients, using intramuscular delivery, that was reported last year, the Company conducted a small, five-patient Phase I/II study to evaluate intradermal delivery of TroVax as an alternative method of administration.  As with the intramuscular trial, all the primary end-points of the intradermal study were achieved, in that the product was found to be safe and all patients mounted an anti-tumour immune response. This brings the number of patients treated in the combined Phase I/II studies to seventeen. Sixteen of these produced the desired immune response.

Vaccines delivered intradermally have been found to give more potent immune responses for infectious diseases such as AIDS. The Company therefore embarked on a small trial to determine whether the same was true for its cancer vaccine in humans. Encouragingly, all five patients in the trial showed an anti-tumour immune response.  Furthermore, two patients who generated high levels of anti-5T4 antibodies to TroVax, experienced periods of disease stabilisation and are presently still on study one year after their first TroVax vaccination. All five patients treated are still alive, 6-12 months after initiation of treatment.  TroVax was well tolerated in all patients treated.

These additional clinical trial data confirm the immunogenic efficacy of TroVax that was seen in the earlier intramuscular study, and highlight the product’s therapeutic potential. Given that high levels of response were seen with both the intradermal and intramuscular routes of administration, the Company has decided to conduct further trials with TroVax using the simpler intramuscular route. TroVax is currently being assessed in a Phase II trial in late stage (Stage IV) colorectal cancer patients in conjunction with chemotherapy, and further Phase II trials in colorectal cancer, renal cancer and breast cancer are planned for 2003.

Commenting on the presentation, Oxford BioMedica’s chief executive, Professor Alan Kingsman said, “It is pleasing to see the encouraging data of the first Phase I/II trial repeated in this additional study. The AACR is the perfect forum to communicate these data to clinicians and to pharmaceutical companies.”

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Notes to editors

1. Oxford BioMedica

Based in Oxford, UK, Oxford BioMedica is a biopharmaceutical company specialising in the development of novel gene-based therapeutics for the treatment of cancer, neuro-degenerative disease and other disorders with major unmet clinical needs. The Company was established in 1995 as a spin out from Oxford University, and is listed on the London Stock Exchange.

In addition to its technical research skill-base, Oxford BioMedica has in-house clinical, regulatory and manufacturing know-how. The development pipeline includes two novel anti-cancer products in clinical trials and a gene-based treatment for Parkinson’s disease, which is in late preclinical studies. The Company is underpinned by an extensive preclinical and research portfolio and over 70 patent families, about quarter of which are issued.

TroVax®, which is Oxford BioMedica’s lead cancer immunotherapy product, is in Phase II trials for colorectal cancer (see below). MetXia® is Oxford BioMedica’s lead gene-based cancer therapeutic. The product is based on a highly engineered retrovirus gene delivery system expressing a specific human cytochrome P450 gene. MetXia converts the tumour into a ‘drug factory’, enabling increased local production of the anti-tumour, cytotoxic derivative of the pro-drug cyclophosphamide. MetXia is potentially useful in the treatment of all solid tumours and their metastases, particularly those where cyclophosphamide is commonly used. MetXia is being investigated in a Phase I/II trial in breast cancer, and regulatory submissions are under review for trials in pancreactic cancer.

Oxford BioMedica has a wholly-owned subsidiary in San Diego, USA. Oxford BioMedica has corporate collaborations with Wyeth, Intervet, Aliga Pharmaceuticals, Amersham, Arius Research and Viragen.

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 protein.

TroVax has completed two Phase I/II trials in the UK in late-stage colorectal cancer, one with intramuscular administration and the other with intradermal administration using the Bioject needle-free injection system. Following these two successful Phase I/II trials, TroVax has entered two Phase II trials in Stage IV colorectal cancer patients receiving 5FU plus either oxaliplatin or irinotecan. The product is also on target to enter further trials in colorectal, renal and breast cancer. The renal and breast cancer trials are to be conducted in the United States under an Investigational New Drug (IND) application. Data from the first TroVax Phase II trial is expected to be available by the end of 2003, in readiness for Phase III trials in colorectal cancer.