A trial of enzalutamide for prostate cancer that has spread and is not responding to hormone therapy (PREVAIL)

Cancer type:

Prostate cancer




Phase 3

This trial looked at a drug called enzalutamide (pronounced en-za-loo-ta-mide) for prostate cancer. The trial was for men who had prostate cancer that had spread to other parts of the body and was getting worse despite hormone therapy. It was for men who had not already had chemotherapy for prostate cancer. Enzalutamide is also called MDV3100.

Prostate cancer depends on the male hormone testosterone Open a glossary item for its growth. Doctors use different types of hormone therapy either to reduce the amount of testosterone in the body, or to stop it reaching and acting on the cancer cells. This can shrink a prostate cancer or slow its growth.

Hormone therapy usually works well, but after a while prostate cancer may stop responding. Doctors are looking for new treatments to help men in this situation. In this trial, they looked at a new hormone therapy drug called enzalutamide.

Prostate cancer cells have receptors Open a glossary item that testosterone attaches to. Enzalutamide blocks these receptors and so blocks the activity of the hormone. It is called an ‘androgen-receptor antagonist’.

The aims of this trial were to

  • See if enzalutamide helped men with prostate cancer to live longer or if it slowed down the growth of the disease
  • Learn more about the side effects and what happened to enzalutamide in the body

Summary of results

The trial team found that enzalutamide did help men with prostate cancer that had spread and was getting worse despite other hormone therapy.

This was a randomised trial. The 1,717 men who took part were put into 1 of 2 treatment groups. Neither they nor their doctor could choose which group they were in. The men and their doctor also didn’t know which group they were in. This is called a double blind trial.

  • 872 men had enzalutamide
  • 845 men had a dummy drug (placebo Open a glossary item)

A year after treatment the researchers looked at how many men had no sign of their cancer getting worse. They found that

  • 569 men (65%) who had enzalutamide had no sign of cancer
  • 118 men (14%) who had the dummy drug had no sign of cancer

After an average follow up of just under 2 years, the team looked at how many men were still alive. They found that

  • 626 who had enzalutamide were alive
  • 532 who had the dummy drug were alive

The most common reported side effects of enzalutamide were

  • Tiredness (fatigue)
  • Back pain
  • High blood pressure
  • Joint pain

The trial also found that for the men who had enzalutamide, there was an average delay of 17 months before they needed to have chemotherapy.  

The trial team concluded that enzalutamide

  • Slowed down the growth of prostate cancer
  • Helped men with prostate cancer live longer  
  • Had few side effects
  • Significantly delayed the need for chemotherapy

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

Professor Johann de Bono

Supported by

Experimental Cancer Medicine Centre (ECMC)

If you have questions about the trial please contact our cancer information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:

Oracle 7374

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.”

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