Research published in the prestigious journal 'Nature', has found a new form of immunotherapy that reactivates the response to hormone therapy in advanced prostate cancer.

Research published in the prestigious journal 'Nature', has found a new form of immunotherapy that reactivates the response to hormone therapy in advanced prostate cancer. Excitingly, this research was partly funded by the Movember Foundation.

Hormone therapy is a mainstay of prostate cancer treatment – but tumour cells can grow resistant, leading to a hard-to-treat, advanced form of the disease.

The new study found that blocking a protein produced by a type of immune cells called granulocytic myeloid-derived suppressor cells, restored sensitivity to hormone therapy.

Drugs that block this protein, called IL-23, already exist and are used for autoimmune diseases such as the skin condition psoriasis.

Clinical trials are planned to assess the possible benefit of this new form of immunotherapy – combined with the next generation hormone therapy enzalutamide – in men with advanced prostate cancer.

Scientists at The Institute of Cancer Research and Royal Marsden, London, working with colleagues at the Institute of Oncology Research in Switzerland, found that blood and tumour samples from men with resistant prostate cancer contained higher levels of these suppressor immune cells, and the protein IL-23, than those from men whose cancer still responded to hormone therapy.

Both blocking IL-23, and stopping suppressor cells from moving into the tumour, led to an improved response to hormone therapy – giving the researchers confidence that they identified a key mechanism that drives hormone therapy resistance in prostate cancer.

The researchers believe that IL-23 allows prostate cancer cells to sidestep the need for androgen hormones to fuel their growth.

As myeloid-derived suppressor cells are present in many prostate tumours, the researchers believe that this immunotherapy approach could work in a large proportion of men with the disease.

"Hormone therapy works well in men with prostate cancer, but when the cancer evolves to become resistant to this type of treatment, other options are greatly reduced." Professor Johann de Bono, Regius Professor of Cancer Research at The Institute of Cancer Research, London, said.

"Our study found an important interaction between hormone signalling and the immune system, which could be exploited to reverse hormone resistance in prostate cancer, and boost the effect of widely used prostate cancer drugs such as enzalutamide."

"We are keen to start clinical trials to investigate how we can combine this form of immunotherapy with existing hormone therapies, to improve treatment for men with advanced prostate cancer."

Professor Paul Workman, Chief Executive of The Institute of Cancer Research, London, added:

"Traditional immunotherapies have shown great promise in many cancer types, but so far their benefit in prostate cancer has been limited to a small subset of men."

"This new study turns the approach to immunotherapy in prostate cancer on its head, and has uncovered a completely different way to harness the immune system to combat the disease."

"Combination treatment of hormone therapy with immunotherapy could be a really exciting new avenue of treatment for advanced prostate cancer, and it's important this approach is tested in clinical trials."

Read the original press release.