Called a “p110δ inhibitor”, the drug has already shown such remarkable effects against certain leukaemias in clinical trials that patients on the placebo were switched to the real drug.
However, a new study, published in the journal Nature and led by British scientists, provides the first evidence that the drug can significantly restrict tumour growth and spread, and reduce the chances of relapse, for a broad range of cancers.
Researchers at UCL, the Babraham Institute, Cambridge, and Queen Mary University of London, together with scientists from Genentech, South San Francisco, showed that the drug – which inhibits the “p110δ” enzyme – helps boost the body’s immune system to kill tumour cells.
Professor Bart Vanhaesebroeck, of the UCL Cancer Institute, said: “Our study shows that [these] inhibitors have the potential to offer effective immunity to many types of cancer by unleashing the body’s own immune response.”
The researchers showed that inhibiting the enzyme in mice significantly increased cancer survival rates across a broad range of tumour types. Their cancers also spread significantly less, with fewer and smaller tumours developing.
The research highlighted that after the enzyme was blocked, the immune system could develop an effective memory response to completely fight off the cancer.
Lead author Dr Khaled Ali said: “We found that ‘p110δ’ is especially important in so-called regulatory T cells which are suppressive immune cells that the tumours engage to protect themselves against immune attack.”
Dr Klaus Okkenhaug, of the Babraham Institute, said: “Our work shows inhibitors can shift the balance from the cancer becoming immune to our body’s defences towards the body becoming immune to the cancer, by disabling regulatory T cells. This provides a rationale for using these drugs against both solid and blood cancers, possibly alongside cancer vaccines, cell therapies and other treatments that further promote tumour-specific immune responses.”
The research was funded by Cancer Research UK, the Biotechnology and Biological Sciences Research Council and the Wellcome Trust.
Professor Nic Jones, Cancer Research UK’s chief scientist and director of the Manchester Cancer Research Centre, said: “Treatments that train the immune system to recognise and kill cancer cells are showing huge promise.
“This new finding, although only at an early stage, offers the potential to develop more treatments that can do this in many more cancers, including ones that have real need for more effective treatments such as pancreatic cancer.
“If the findings hold true in cancer patients, this could make a big difference to many of them. The good news is that because the drugs used in this study are already being used in the clinic, we could see rapid translation of this into patient benefit.”