Scientists have found that a naturally occurring virus could be used to treat people with aggressive brain tumours by drastically boosting the immune system.
The study, which has been published in Science Translational Medicine, found that reovirus was able to cross the blood-brain barrier where it would then replicate and kill the cancerous cells.
Up to now, scientists believed it would be impossible for a virus to cross through the blood-brain barrier, making it significantly more difficult to administer the virus as a form of treatment.
However the results of the study have shown that the virus can be administered through a simple intravenous drip and can then travel up to the brain.
In addition to attacking the cancer cells the team also found that the virus was able to ‘switch-on’ the body’s immune system which could then attack the cancer.
This second point is significant.
“Our immune systems aren’t very good at ‘seeing’ cancers ― partly because cancer cells look like our body’s own cells, and partly because cancers are good at telling immune cells to turn a blind eye. But the immune system is very good at seeing viruses.” explains Co-lead author Alan Melcher, Professor of Translational Immunotherapy at The Institute of Cancer Research, London.
“In our study, we were able to show that reovirus could infect cancer cells in the brain. And, importantly, brain tumours infected with reovirus became much more visible to the immune system.”
The study itself involved nine patients. Each of them had cancers that had either spread to the brain from other parts of the body or were gliomas, a type of brain cancer that’s very difficult to treat.
All nine were due to have their tumours removed surgically, however in the days leading up to the operation they were given the virus through a drip.
After the surgery they looked at tissue samples from the nine patients and then samples from other patients who had had the surgery but not the virus drip.
Within the samples of those who had been given the drip, the team found evidence of the virus ‘switching-on’ the body’s immune system and then attacking the tumour.
Despite it being such a small sample, the results of the study were so conclusive that a clinical trial is already underway.
“Now we know we can get reovirus across the blood-brain barrier, we have begun clinical studies to see just how effective this viral immunotherapy can be at extending and improving the lives of patients with brain tumours, who currently have very limited treatment options available to them.” explains Professor Melcher.
Leading the clinical trial is Susan Short, Professor of Clinical Oncology at the University of Leeds. She said:
“Brain cancer is a devastating disease. For a long time, there have not been many new developments that we could offer patients but the research that is happening at the University Leeds and elsewhere is beginning to offer a new approach.”