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

Cancer type:

Prostate cancer

Status:

Results

Phase:

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 )

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.