Phase II trials of TroVax

Oxford Biomedica PLC
16 May 2005



                                                               
FOR IMMEDIATE RELEASE                                                16 MAY 2005




OXFORD BIOMEDICA PRESENTS UPDATED AND ENCOURAGING TROVAX(R) PHASE II RESULTS IN
               COLORECTAL CANCER AT THE 2005 ANNUAL MEETING


Oxford, UK: 16 May 2005 - Oxford BioMedica (LSE: OXB), the leading gene therapy
company, today announced that new and encouraging data were presented from the
Phase II trials of TroVax, its cancer immunotherapy, in colorectal cancer at the
2005 American Society of Clinical Oncology (ASCO) Annual Meeting, in Orlando,
Florida, USA, on Sunday, 15 May 2005.


The presentation included data reported in March 2005 from the two Phase II
trials in first line treatment of metastatic colorectal cancer alongside
irinotecan-based (IFL) and oxaliplatin-based (FOLFOX) chemotherapy. In addition,
further immune response data were presented. These show that the maximum
antibody levels (titres) targeted against the 5T4 tumour antigen in the Phase II
studies are significantly higher than in the Phase I/II trial in
post-chemotherapy patients. Peak titres reached levels of 5,000 in the
TroVax+IFL trial and 1,200 in the TroVax+FOLFOX trial. These are four- to
ten-fold higher than in the Phase I/II study. This may be important because, in
that earlier study, there was a highly significant (p<0.0001) correlation
between antibody titre and time to disease progression amongst responders.


Additional new data include analysis of the anti-5T4  killer T-cell (CD8)
response following immunisation with TroVax. Killer T-cells are widely believed
to be important antitumour cells. Encouragingly, 83% of patients in the
TroVax+IFL study and 71% in the TroVax+FOLFOX trial developed anti-5T4 killer
T-cells, reaching levels as high as 1 in 1,000 white blood cells. This level is
comparable with those seen in viral infections that are cleared by circulating
antiviral killer cells. Interestingly, in the TroVax+FOLFOX trial, the two
patients that showed complete tumour responses (tumour clearance) had the
highest antibody and killer T-cells levels. This links, as in the Phase I/II
trial, the anticancer immunological effect of TroVax immunisation to clinical
benefit.


As previously reported, the primary endpoints in the two trials of safety and
immunological responses were achieved. All 25 patients that have reached the
interim stage of the trial have shown an immune response to the 5T4 tumour
antigen. In addition, the secondary endpoint of clinical benefit exceeded
expectation. Eighteen of 19 evaluable patients responded to treatment. Whilst
five patients had disease stabilisation following treatment, 13 of the 19
patients (68%) were defined as clinical responders according to industry
standard criteria, comprising three complete and ten partial responses.


Two independent studies of the chemotherapy regimens alone reported clinical
response rates in evaluable patients of 41% and 50% respectively (Douillard et
al., The Lancet 2000, vol 355, pp 1041-1047; de Gramont et al., Journal of
Clinical Immunology 2000, vol 18, pp2938 -2947). However, a precise comparison
with the TroVax trials is not possible owing to differences in the trial
protocols and patient numbers.


Enrolment in the trials was completed in September 2004 with 36 patients
recruited. The trials are on track to report full safety and immunological data
as well as final audited tumour response statistics in the second half of 2005.
Patient survival, which can be compared to historical controls, will be reported
once the median survival has been reached in the two trials. This is anticipated
in early 2006.


This ASCO abstract on the TroVax Phase II results may be accessed online at
http://www.asco.org at the conclusion of the meeting on 17 May. The abstract
title is as follows:


'An Open Label Phase II Study of MVA Expressing the Tumour Antigen 5T4 Given in
Conjunction with Chemotherapy: Safety and Immunogenicity Before, During and
After Chemotherapy.' (Abstract #30642)


Commenting on the ASCO presentation of TroVax Phase II results, Oxford
BioMedica's Chief Scientific Officer, Dr Sue Kingsman, said: 'We are very
pleased with the new data from the TroVax Phase II trials. Given what we know
from the previous colorectal cancer trial, we are hopeful that the stronger
anti-5T4 responses in the first line treatment setting will lead to a
corresponding extension of time to disease progression and survival. Based on
current data, we are optimistic that TroVax will have a role to play in the
treatment of colorectal cancer and we look forward to this being evaluated in
pivotal clinical studies'.


                                     -Ends-


For further information, please contact:
Oxford BioMedica plc:

Professor Alan Kingsman, Chief Executive                Tel: [phone]
City/Financial Enquiries:

Lisa Baderoon/ Mark Court/ Mary-Jane Johnson Buchanan   Tel: [phone]
Communications
Scientific/Trade Press Enquiries:

Sue Charles/ Katja Stout/ Ashley Lilly                  Tel: [phone]
Northbank Communications



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 the areas of
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 an immunotherapy and a gene therapy in multiple Phase II trials, and a
preclinical targeted antibody therapy in collaboration with Wyeth. In
neurotherapy, the Company's lead product is a gene therapy for Parkinson's
disease, which is expected to enter clinical trials in early 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 65 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, Amersham,
Viragen, MolMed and Kiadis; and has licensed technology to a number of companies
including Merck & Co and Biogen Idec.


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


2. TroVax(R) cancer immunotherapy

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.


In Phase I/II trials in late stage colorectal cancer patients, TroVax was safe
and well tolerated; patients mounted an anti-5T4 immune response; and the immune
response correlated, with high significance, to time to disease progression,
which translated into a correlation with improved overall survival.


Four Phase II trials are underway. Positive initial data from trials
investigating TroVax in colorectal cancer in combination with first line
standard of care treatment and as a (neo) adjuvant to surgery were released in
March 2005. The primary endpoints of safety and immunological responses were
achieved. In the two trials of TroVax alongside chemotherapy, the secondary
endpoint of tumour response rate exceeded expectation.


A further Phase II trial is ongoing in renal cell carcinoma, and the US National
Cancer Institute, through the Southwest Oncology Group, is planning a Phase II
trial in breast cancer.


3. ASCO

The American Society of Clinical Oncology is the world's leading professional
organisation representing physicians who treat people with cancer. ASCO's
members set the standard for patient care worldwide and lead the fight for more
effective cancer treatments, increased funding for clinical and translational
research, and, ultimately, cures for the many different cancers that strike
millions of people around the world every year.






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