A trial of custirsen with docetaxel for prostate cancer that has spread (SYNERGY)

Cancer type:

Prostate cancer




Phase 3
This trial looked at a drug called custirsen with chemotherapy for prostate cancer.
It was for men whose:
  • cancer had spread to other parts of the body (advanced cancer)
  • hormone therapy had stopped working
This trial was open for men to join between 2010 and 2012. The researchers published results in 2017.

More about this trial

Cancer that has spread elsewhere in the body is called advanced cancer. Docetaxel chemotherapy is a usual treatment for advanced prostate cancer if hormone therapy has stopped working. Treatment might also include a steroid Open a glossary item called prednisolone. 

In this trial, doctors looked at adding a type of targeted drug called custirsen (OGX-011) to improve treatment. 

Some cancer cells produce a lot of a protein called clusterin. This may help them to protect themselves from cancer drugs and stop the drugs working as well as they could. Custerin reduces the level of clusterin. Researchers hoped that by lowering the levels of clustirsen, the cancer drugs would work better.

In this trial, some men had docetaxel, prednisolone and custirsen. And some had docetaxel and prednisolone. 

The aim of the trial was to see if adding custirsen to docetaxel and prednisolone improved treatment for advanced prostate cancer.  

Summary of results

The trial team found that adding custirsen to docetaxel and prednisolone didn’t work better than docetaxel and prednisolone. 
This phase 3 trial took place worldwide. Men were put into 1 of the following treatment groups at random.
Of the 1,022 men who took part:
  • 512 had docetaxel and prednisolone
  • 510 had docetaxel, prednisolone and custirsen

The trial team looked at the length of time men lived after treatment. This is called overall survival. They found this was:
  • 22 months in men who had docetaxel, prednisolone and custirsen
  • just over 23 months (23.4) in men who had docetaxel and prednisolone
So, adding custirsen didn’t improve overall survival. 
Side effects
Men who had custirsen, docetaxel and prednisolone had more problems with:
  • an increased risk of infection
  • low levels of white blood cells Open a glossary item with a fever
  • a drop in the number of red blood cells (anaemia Open a glossary item)
  • liver changes
  • tiredness
  • weakness or lack of energy
  • diarrhoea
Men who had custirsen also had more fever and chills, but this was due to an infusion reaction. 
The research team concluded that adding custirsen to prednisolone and docetaxel wasn’t better than prednisolone and docetaxel for advanced prostate cancer. Although the side effects weren’t too bad. 
But all trial results help doctors and researchers understand more about different cancers and the best way to treat them.
Researchers ran other trials that looked at custirsen for prostate cancer when other treatments had stopped working. One trial was called AFFINITY and there is a summary of the results on the CRUK clinical trials database. 
Where do these results come from
We have based this summary on information from the research team. 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 who did the research. 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)
NIHR Clinical Research Network: Cancer
Teva Pharmaceutical Industries Ltd

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

Freephone 0808 800 4040

Last review date

CRUK internal database number:


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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