A new study suggests olaparib could boost the efficacy of treatment for earlier-stage prostate cancer, after discovering how it can block the repair of DNA in cancer cells no matter what kind of the disease they have.

5 Sep 2017

New research has found a commonly-used ovarian cancer drug, olaparib, could help make treatment of prostate cancer at an earlier stage more effective.

Published in Nature Communications today, the results of the study suggest that drugs known as PARP inhibitors – like olaparib – could help to weaken the cancer in combination with hormone therapy and radiotherapy by stopping the cancer cell from repairing its DNA.

Prostate Cancer UK is already funding research into using olaparib as a treatment for men who have become resistant to all other drugs, but it only works if they have a specific mutation in their cancer that affects DNA repair. This new study's findings, if confirmed, could mean many more men with prostate cancer might benefit from the drug.

Foiling the cancer’s back-up repair mechanism

One of the key issues in treating prostate cancer is to prevent it from becoming resistant to treatment or returning afterwards. Radiotherapy helps to kill cancer cells by damaging and breaking apart their DNA, which they have to repair in order to survive. The repair-work is made even more difficult when hormone therapy is given alongside radiotherapy, but the cancer can switch to using a back-up mechanism.

This back-up relies on a protein called PARP1, and the scientists involved in this new research could see that PARP1 was more active when the cells were treated with radiotherapy and hormone therapy.

Fortunately, drugs have already been developed to stop PARP1 from working – such as olaparib, which is used to treat ovarian cancer. The researchers tested olaparib on their prostate cancer samples and found that it made the cells more sensitive to treatment. It suggests the drug may help hormone therapy to stay effective for longer and make it more difficult for the cancer to become resistant.

Getting maximum benefit from existing treatments

"One man dies from prostate cancer every 45 minutes and Prostate Cancer UK is determined to stop this tragic loss of life," says Dr Matthew Hobbs, our deputy director of research. "But to do that, we need to get the maximum benefit from new and existing treatments.

"PARP inhibitors have already been shown to work in other cancers, and in some late-stage prostate cancers. By explaining more about how prostate cancer grows, this important new research helps to show how PARP inhibitors might also be able to fight the cancer at an earlier stage.

"These results build on previous research funded by Prostate Cancer UK, and we're pleased to see it reach this point. Changes to treatment won’t happen overnight but this understanding of what is happening in a man’s body should help increase the success of clinical trials, and maximise the number of men who can benefit from this new way of treating prostate cancer."

 

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