London: Scientists have developed a novel treatment for brain tumours that involves encouraging the body's own immune system to recognise and eliminate cancer cells in the organ. Glioblastoma is one of the most ominous brain tumours. Despite aggressive surgery, radiation and chemotherapy the outcome of this disease is almost always fatal, researchers said. Animal experiments show that it is relatively easy to treat cancer in the early stages. However, it is far more difficult to successfully treat advanced cancer.
Treatment of brain tumours is particularly challenging because regulatory T-cells accumulate in brain tumours and suppress an immune attack. In several steps using a new strategy and a novel drug, Burkhard Becher's team from the Institute of Experimental Immunology at The University of Zurich has now succeeded in doing exactly this in the case of glioblastoma, one of the most dangerous brain tumours. They stimulated the body's own immune system in such a way that it recognised and then killed the brain tumour cells even in advanced stages of the disease. The initial objective of their new study was to break through the tumour's protective shield.
"We wanted to establish whether we can actually elicit an immune response to a tumour growing within the brain," said Becher. To this end, the team used the immune messenger substance, Interleukin-12. When Interleukin-12 is produced in the tumour, immune cells are stimulated locally in such a manner that the tumour is attacked and rejected. Once this procedure had worked well in the early stages of the tumour, the researchers waited in the next stage until the tumour was very large and the life expectancy of the untreated test animals was less than three weeks.
"We only began treatment when it was, in fact, already too late," said the first author of the study Johannes vom Berg, adding the success rate was low. "We then injected biopharmaceutical Interleukin-12 into the large brain tumour. This did induce an immune response but only led to tumour rejection in one-quarter of the animals." said Berg. The researchers were successful when they drew on a new development in skin cancer treatment. They combined intra-tumoral Interleukin-12 treatment with the intravenous administration of a novel immunostimulating drug that suppresses the regulatory T-cells. The rejection of the tumour then worked in 80 per cent of the test animals.
