A trial looking at abiraterone acetate and prednisolone for men with prostate cancer that has spread to another part of the body (COU-AA-301)

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Cancer type:

Prostate cancer




Phase 3

This trial was looking at a drug called abiraterone acetate and the steroid prednisolone for men with prostate cancer that had spread and was no longer responding to hormone therapy or chemotherapy.

Doctors usually treat advanced prostate cancer with hormone therapy and chemotherapy. But if these treatments stop working, the cancer can be more difficult to control.  Doctors sometimes give the steroid prednisolone to treat advanced prostate cancer that has stopped responding to other treatments.

Abiraterone acetate works in a different way to other hormone treatments for prostate cancer. It blocks an enzyme Open a glossary item called CYP17. This stops the body making the male hormone testosterone. Testosterone helps prostate cancer to grow. Doctors think that blocking the action of CYP17 could help to slow the growth of prostate cancer.

In this trial two thirds of the men had abiraterone and prednisolone. The rest had a dummy drug (placebo Open a glossary item) and prednisolone. The aims of the trial were to

  • See if having abiraterone acetate helped men with advanced prostate cancer to live longer
  • Learn more about the side effects

Summary of results

The researchers found that in this trial, the average length of time men lived was

  • Just under 16 months in the abiraterone group
  • Just over 11 months in the placebo group

The trial recruited 1,195 men with advanced prostate cancer who had already had the chemotherapy drug docetaxel.

  • 797 men had abiraterone and prednisolone tablets each day
  • 398 men had a dummy drug and prednisolone tablets each day

Doctors often measure the level of PSA in the blood to see how well prostate cancer treatment is working. In this trial, PSA tests showed that prostate cancer responded to treatment more often in the group of men having abiraterone than in the group having the placebo.

The trial team also looked at how long it was before PSA tests showed the cancer had started to grow again. On average, this was

  • Just over 10 months for men who had abiraterone
  • Just over 6 and a half months for men who had the placebo

Men in the abiraterone group had more problems such as fluid retention, changes to the way their liver worked and heart problems. But only a small number of men had serious side effects.

The trial team concluded that abiraterone helps men who have already had docetaxel for advanced prostate cancer to live longer, without causing too many side effects.

We have based this summary on information from the team who ran the trial. The information they sent us has been reviewed by independent specialists (peer reviewed Open a glossary item) and published in a medical journal. The figures we quote above were provided by the trial team. We have not analysed the data ourselves.

Recruitment start:

Recruitment end:

How to join a clinical trial

Please note: In order to join a trial you will need to discuss it with your doctor, unless otherwise specified.

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Chief Investigator

Prof Johann de Bono

Supported by

Cougar Biotechnology
Experimental Cancer Medicine Centre (ECMC)
Johnson and Johnson

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Last review date

CRUK internal database number:

Oracle 693

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Keith took part in a trial looking into hormone therapy

A picture of Keith

"Health wise I am feeling great. I am a big supporter of trials - it allows new treatments and drugs to be brought in.”

Last reviewed:

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