A new treatment, which involves the administering of viruses to patients directly into the bloodstream, has been used to effectively treat aggressive brain tumours. The treatment works by stimulating existing internal immunity. “The presence of cancer in the brain dampens the body’s own immune system,” said Professor Susan Short, an oncologist at the University of Leeds, who led the trial.
Researchers analysed surgically removed brain tumours for signs of immune system response, in patients who’d had the viruses administered before the operation. The findings were that, in all patients who took part, there was evidence that an immune response had been stimulated – even in tumours that were deep in the brain. The virus itself seemed to cause flu symptoms in the patients, but no other serious side effects were reported.
The findings are part of a wider clinical trial, where viruses are introduced in order to “switch on the immune systems response” to the cancer. It adds to the growing evidence that immunotherapy, which is already being used to treat certain types of tumours, could be more widely used for cancer treatment. The discovery of this new treatment is promising to medical professionals, as brain tumours can be particularly hard to treat and can become aggressive.
“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,” said Professor Alan Melcher, a researcher at The Institute of Cancer Research, who co-led the study. “But the immune system is very good at seeing viruses” he added
The main breakthrough of this trial is the discovery that the viruses were able to pass through the “blood brain barrier”, which usually prevent substances found in the bloodstream from entering the brain. Without this ability, viruses would need to be injected into the brain which is unlikely to be approved due to the associated risks.
The successes seen in this research has led to another ongoing, larger-scale clinical trial.“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,” said Prof Melcher. He then added that “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 of Leeds and elsewhere is beginning to offer a new approach.”