September 13, 2018

Immunotherapy offers hope for men

New drugs have given thousands of men with aggressive prostate cancer fresh hope of beating the disease.

Around 10% of prostate cancer cases diagnosed each year have DNA mutations in their tumours and they do not respond to traditional treatments.

Trials are now under way to test immunotherapy drugs, which supercharge the body’s immune system to fight disease in those who are resistant to traditional treatments.

DNA defects cause cells to turn cancerous and multiply but a new generation of drugs which include pembrolizumab, destroy the cancerous cells.

Immunotherapy uses the body’s own immune system to help fight disease and has been shown to be effective in treating bowel cancer among others.

Study leader Professor Johann de Bono, of the Institute of Cancer Research, London, said: "Prostate cancer has been treated as one disease but for the first time we have shown there are multiple different subsets. It’s like fixing a broken car – you wouldn’t carry out the same repair for every vehicle that comes into a garage."

"People didn’t think immunotherapy would work in prostate cancer, but we are saying they are wrong. Actually, we have a lot of evidence that certain DNA repair defects in cancer are very sensitive to immunotherapy," he added.

Sometimes the immune system can identify cancer cells but can’t mount a strong enough response to get rid of them. In other cases, cancer cells hide by hijacking our body’s safety mechanisms. Immunotherapy treatments help your immune system recognize cancer cells and destroy them.

Currently, a few immune control points are targeted for cancer treatment, including the PD-1 and PD-L1 checkpoints. PD-1 is on the surface of immune cells (T cells). It disables the immune system to prevent it from attacking the normal cells of the body. This process is important for normal cells, but cancer cells use it to avoid attack by the immune system. Checkpoint inhibitor drugs, like pembrolizumab, bind to these surface markers, reactivating the immune system against cancer cells.

The researchers looked at the prostate cancer cells from tumor biopsies and tested for the levels of a protein called PD-L1. Published this month in the Journal of Clinical Investigation, the study found that 50% of all men with mismatch repair defects in their tumors had high PD-L1 levels. The published work builds upon results presented at the American Society for Clinical Oncology meeting in June, which indicated that DNA mismatch repair defects were associated with a favorable response to pembrolizumab.

The Institute of Cancer Research in London is developing tests that could pick out patients with these mutations and are running clinical trials to see if pembrolizumab can offer hope to men who do not respond to traditional treatments.

In trials, those with advanced prostate cancer are given 200mg of pembrolizumab every three weeks for at least 18 months.

Professor Paul Workman, Institute chief executive said: "We are seeing a revolution in cancer treatment as immunotherapy becomes an important option."

Dr Matthew Hobbs, of Prostate Cancer UK, said: "Although it’s still early days, the results provide another piece of the jigsaw which will eventually help doctors decide on the best treatment for each individual man."


Journal of Clinical Investigation Sept. 2018 - Immunogenomic analyses associate immunological alterations with mismatch repair defects in prostate cancer
FORBES Sept. 2018 - Immunotherapy Offers Hope For Some Men With Aggressive Prostate Cancer
ASCO June 2018 - Major trial is first to show benefits of immunotherapy in some men with prostate cancer

Written by PROCURE. © All rights reserved - 2018


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