Breakthrough research has shown the pairing of immunotherapy and a virus cured up to 90 percent of mice plagued by triple negative breast cancer, the deadliest form. This combination could treat aggressive breast cancer, according to Canadian scientists.
They are hopeful the findings will lead to a potential cure since survival depends on how early the disease is caught.
Ottawa University scientists who led the trial said a separate study found that an injection of a virus could also treat aggressive brain tumors.
Dr. Marie-Claude Bourgeois-Daigneault, the lead author of the Canadian study, was full of praise for the findings that may apply to humans.
She said: ‘It was absolutely amazing to see that we could cure cancer in most of our mice, even in models that are normally very resistant to immunotherapy.’
‘We believe that the same mechanisms are at work in human cancers, but further research is needed to test this kind of therapy in humans.’
Each year in the UK 11,400 people die from breast cancer while in the US, the figure is around four times higher.
Charities estimate around 15 percent of all cases of breast cancer is triple negative – but death rates are proportionally higher.
Science Translational Medicine who published the study, adds to the growing body of evidence that shows the vast benefits of immunotherapy.
The mice in the study were resistant to the checkpoint inhibitor, which blocks proteins on cancer cells to stop them from growing, that was used.
This type of drug, which was made famous by nivolumab, sometimes referred to as the weapon of choice for ‘every oncologist in the first world’ is already used to treat some forms of cancers, including lung and kidney.
Separate trials showed an oncolytic virus called Maraba boosted the immune system of the mice while attacking the cancerous cells.
It had little effect, however, on the survival of mice on its own. The rodents were engineered to be in a state of metastasis when cancer has spread from the original location.
When it was used alongside the checkpoint inhibitor, the cure rate was between 60 and 90 percent of the mice, compared to a 0 percent cure rate for the immunotherapy alone and 20 to 30 percent for just a dose of the virus.
The new treatment backs up older trials using the same technique and saw the virus given before surgery and the drug after.
Dr. John Bell, a co-author, added: ‘Our immune system is constantly trying to recognize and kill cancer cells, but the cancer cells are always trying to hide from it.
‘When you infect a cancer cell with a virus, it raises a big red flag, which helps the immune system recognize and attack cancer. But in some kinds of cancer, this still isn’t enough.’
‘We found that when you add a checkpoint inhibitor after the virus, this releases all the alarms and the immune system sends in the full army against cancer.’
Researchers confirmed oncolytic viruses and checkpoint inhibitors have the potential for treating melanoma.
The new study was the first to test viruses and checkpoint inhibitors in a surgery and metastasis model.
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