Prostate tumour genetic testing could identify likely responders to immunotherapy

Scientists at The Institute of Cancer Research (ICR) London and the University of Michigan have found a distinct pattern of genetic changes that could identify men with advanced prostate cancer who are more likely to respond to immunotherapy. An analysis of tumour DNA from 360 men across the globe with advanced prostate cancer showed that both copies of the CDK12 gene were missing in the tumours of 7% of them. This type of tumour had more immune cells and more neoantigens on the surface than other forms of advanced prostate cancer.

It is hoped that further research on a bigger sample size could result in the introduction of a genetic test as a precursor to offering immunotherapy, and the exploration of CDK12 as a genetic weakness that could be targeted by new prostate cancer drugs. “The identification of CDK12 loss as a possible biomarker for identifying prostate cancer patients who may respond to checkpoint immunotherapy is a hugely significant finding, as researchers have struggled with how to effectively use immunotherapy in prostate cancer for many years. The Prostate Cancer Foundation is proud to have funded this foundational study.” said Howard Soule, Ph.D., executive vice president and chief science officer of the Prostate Cancer Foundation.

“Immunotherapy works for a relatively small group of men with advanced prostate cancer – but when it works, it really works. If we can identify in advance who will benefit, then it should accelerate the passage of immunotherapy into routine use for patients. Our new study has revealed a distinct group of men with advanced prostate cancer whose tumours have biological features that could make them likely to respond to immunotherapy drugs such as pembrolizumab. We now need larger clinical studies to further study the benefit of immunotherapy in this group of patients. In the future, a genetic test could help pick out men with this particular set of genetic changes, so that they can be considered for immunotherapy,” said Professor Johann de Bono, Regius Professor of Cancer Research at The Institute of Cancer Research, London.