Oxford BioMedica announced interim results from the Phase I/II trial of its anti-cancer therapeutic vaccine, TroVax, at the 9th Annual BioPartnering Europe conference in October 2001
Initial results show TroVax to be safe and well tolerated and the vaccine induced an immune response against the tumour antigen, OBA1 in colorectal cancer.
These results represent the successful achievement of the primary end-points of the trial.
TroVax is a gene-based therapeutic vaccine that is designed to stimulate the patient's immune system to mount a powerful response to recognise and destroy cancer cells.
The immune system plays a key role in fighting infections and disease.
However with cancer, the patient's immune system often fails to react to the existence of a tumour and as a result an effective immune response is not triggered.
The product is based on a gene that encodes a protein, OBA1, that exists on the surface of tumour cells and not on normal cells - such proteins are known as Tumour Associated Antigens (TAAs).
When the OBA1 gene is expressed by Oxford BioMedica's highly engineered virus-based delivery system, it induces an anti-tumour response.
OBA1 is present on a wide range of tumours.
Although the first clinical trials of TroVax have been conducted in colorectal cancer patients, TroVax is also expected to be applicable to many other solid tumours.
In preclinical model systems the results have been very striking, with TroVax breaking immune tolerance to tumours and protecting against further tumour growth.
This first Phase I/II clinical trial of TroVax, which started in January 2001, confirms that TroVax also causes immune responses against OBA1 to be raised in cancer patients.
The Phase I/II TroVax clinical trial comprises 12 patients at the Dukes D stage of colorectal cancer.
The patients are divided into low, medium and high dose groups.
The low dose group has now been completed and it is these initial results that the Company is reporting.
In all four patients in the low dose group TroVax was tolerated well with no adverse effects.
In three of these patients there are anti-OBA1 immune responses.
The fourth patient has, so far, been unable to mount a response to any antigen tested, for reasons unrelated to the trial.
This is not unusual in patients with advanced cancer that have previously received other forms of therapy.
This means that in all of the patients within this low-dose group who were immunocompetent, an anti-OBA1 response was seen.
The Company has now escalated the dose for the next group which is already fully enrolled.
It is anticipated that preliminary results covering the medium and high dose groups will be released in the first quarter of 2002.
Commenting on the results chief executive professor Alan Kingsman said: "We are pleased that the TroVax trial has achieved its major goals so early in the programme and we look forward to results from the other dose groups.
"We have released these data now because we have had several requests to share the results with the scientific and business communities, however it should be remembered that there is still some way to go before TroVax is shown to be effective in treating human cancer."
