A trial looking at gene therapy for prostate cancer that has continued to grow (GDEPT)

Cancer type:

Prostate cancer

Status:

Results

Phase:

Phase 1/2

This trial was trying to find out more about a new form of gene therapy called GDEPT for prostate cancer.

The trial was open to men who had prostate cancer that had continued to grow despite treatment.

With this treatment, a specially treated virus is injected directly into the prostate cancer. It carries a gene that can turn a harmless drug called CB1954 into an active anti cancer drug. The harmless drug travels through the bloodstream. When the drug reaches the virus infected cancer cells, it is activated by the gene in the virus and kills the cancer.

The aim of this trial were to find out

How good the virus was at getting the genes into the prostate gland
How good the treatment was at killing prostate cancer cells
What the side effects were

Summary of results

The researchers found that this treatment could be given more than once without causing bad side effects. It may have helped some of the 19 men who took part in the trial.

Doctors often measure the level of prostate specific antigen (PSA) in the blood to see how well prostate cancer treatment is working.

When they joined the trial, all the men taking part had a PSA that was rising. In some men, the PSA level had gone down a month after treatment. It went down

Between 10% and 50% in 5 men
More than 50% in 2 men

If the level of PSA was the same or lower, men could have the treatment again and 14 of the men taking part had the treatment twice. In 5 of these men, the prostate cancer had not started growing again after an average follow up period of nearly a year.

The side effects of treatment included

Pain at the injection site
Changes to the results of tests that show how well the liver is working (liver function tests)
A high temperature a few hours after having the injection

None of these side effects lasted very long or needed extra treatment.

During the trial, the researchers changed the way the injections were given. They found that giving 4 injections into the prostate gland was better than just 1.

The trial team suggest these results show that the treatment may have slowed down the growth of prostate cancer in some of the men. But a larger trial would need to be done to find out whether or not this treatment could really help. And they may find other ways to improve the treatment.

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.