‘Revolution’ in prostate cancer care as off-label breast cancer drug doubles survival

This article was taken from: https://www.telegraph.co.uk/science/2019/09/30/revolution-prostate-cancer-care-off-label-breast-cancer-drug/

By Henry Bodkin, health correspondent

Abreast cancer drug has been used to double the survival of men with advanced prostate cancer, becoming the first successful precision medicine for the disease.

Doctors at the Royal Marsden Hospital who conducted the trial say the results amount to a “revolution” in prostate cancer care.

They conducted genetic testing on more than 4,400 patients to identify those with one or more of 15 types of DNA fault.

Those who qualified were given olaparib, a course of pills which is commonly used to treat breast and ovarian cancer but is not currently licensed for prostate cancer.

The men in the trial had already failed to respond to hormone therapy – currently the best treatment available – and their prognoses were poor.

However, their length of progression-free survival, the period during which the cancer does not get worse, increased on average from 3.6 to 7.4 months.

This shows that using DNA testing to match patients with already available drugs can “transform” the treatment of the most common type of male cancer, according to the researchers.

The trial, which is being presented at the European Society for Medical Oncology annual congress in Barcelona, coincides with a new study in the journal Nature which suggests that using genetic information to re-purpose unlicensed or “off-label” drugs could benefit around one-third of patients for whom standard therapies do not work.

Olaparib, a type of PARP inhibitor, works by blocking a protein that fuels cancer by helping damaged cells to repair themselves.

Because it is known to benefit women with breast and ovarian cancer who have BRCA gene mutation – made famous by Angelina Jolie – scientists tested for these and other faults in men.

They found that 80 per cent of men whose tumours had faults in the BRCA genes responded to olaparib.

The teams at the Institute of Cancer Research, The Royal Marsden and Northwestern University in Chicago said this proves that, rather than being a single illness, prostate cancer is a series of sub-types of the disease, requiring tailored treatment for individual patients.

While precision medicine is becoming increasingly mainstream for other forms of cancer, notably breast cancer in the form of Herceptin, it is yet to play a significant role for men with prostate cancer.

Approximately 47,700 men receive a diagnosis in the UK each year, with 11,600 dying from the disease.

Dr Matthew Hobbs, from Prostate Cancer UK, said: “This hugely exciting result represents a revolution in the treatment of prostate cancer.

“It finally brings prostate cancer medicine into the 21st century by giving us, for the first time ever, a therapy that makes use of genetic testing of the tumour to work out which men will benefit.”

In the trial, 387 out of 4,425 patients were identified as having one of the 15 genetic mutations, suggesting olaparib could help at least 11 per cent of patients.

Professor Johann de Bono, a consultant oncologist at The Royal Marsden and ICR, said: “This study is a powerful demonstration of the potential of precision medicine to transform the landscape for patients with the commonest of male cancers.

“I hope that within the next couple of years, olaparib will become the first precision medicine to become available as a standard treatment for men with prostate cancer.”

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