Transcript of audio on the post DNA vaccine could improve immunotherapy for cancer.

“My name is Alan Melcher, I’m Professor of Clinical Oncology and Biotherapy at the University of Leeds.

What we’ve done in this work is that we’re trying to stimulate the immune system to attack cancers, and we’ve developed a treatment based on viruses which we have genetically engineered so that they make proteins called antigens.

When we vaccinate with this virus, these antigens get made, which the immune system recognises and attacks. And because the cancer also makes these antigens, when the immune system is stimulated in this way, it is stimulated to attack the tumour.”

What makes this research different from other vaccine studies we’ve seen recently?

“What we’ve done here is with gene therapy – there’s been quite a lot in the past with using the immune system in gene therapy, but it’s tended to only use very few antigens to stimulate the immune response. What we’ve done here is to take a whole library of DNA from a tissue within which there are lots and lots of different antigens, put that library into a virus, and use that as the vaccine.

What happens there is that the immune system is very good at recognising viruses, so it’s get activated and stimulated. And because these viruses have a library of tumour antigens within them, the activated immune system can also recognise and attack the cancer.”

Are there any concerns about this over-stimulating the immune system?

“Yes – that has always been (and remains) a concern in any immune-based treatment. But certainly in the experiments we’ve done to date, we have not seen a problem with over-activation of the immune system causing toxicity or side effects from this virus DNA library approach.”

So what does this mean for patients at the moment?

“It is very early days in terms of applying this to patients. What we can say is that viruses similar to the one that we’ve used here have been used in trials and are looking quite promising, so the platform is there and appears safe and deliverable. So I think there’s reason for optimism that this particular vaccine approach can be a future development of current virus-based treatments.

The next steps are for us to widen the application of this particular approach, so to take forward the idea of DNA virus vaccine libraries. We want to explore this in a range of different tumours, and more using these treatments not by themselves but in combination with standard treatments such as chemotherapy.”