A prostate cancer cell.
Men with prostate cancer that has spread who are starting long-term hormone therapy may benefit from either of two additional treatments, according to unpublished clinical trial results.
The results, based on analysis of data from the Cancer Research UK-funded STAMPEDE trial, show that standard hormone therapy combined with another hormone therapy called abiraterone (Zytiga) or a chemotherapy drug called docetaxel give comparable improvements in survival compared to standard hormone therapy alone.
Results of the analysis will be presented at the 2017 ESMO Congress in Madrid.
The STAMPEDE trial is a multi-stage trial that is comparing the standard care – hormone therapy – with the standard care plus the addition of one or more other treatments for prostate cancer.
There are seven different drug combinations being tested in the trial. The aim of STAMPEDE is to see which treatment is best for prostate cancer that has spread outside the prostate gland, either locally or to other areas of the body.
The latest study combines data from two parts of the trial. It includes 566 men who were starting long-term hormone therapy, and were given either abiraterone plus a steroid called prednisolone or docetaxel.
Patients who took abiraterone plus prednisolone or docetaxel alongside hormone therapy survived longer than those taking hormone therapy alone.
Overall, there was no significant difference in survival between groups who took abiraterone plus prednisolone or docetaxel.
Side effects experienced by patients taking the extra drugs were also similar.
Professor Nick James, from the University of Birmingham who leads the trial, said: “Both drugs provide a survival advantage over standard of care alone in men with high risk prostate cancer beginning long-term hormone therapy.
“This study suggests that starting with either drug is acceptable and choice may depend on availability.”
Abiraterone is not yet approved for routine NHS use in these men. It is only approved for men who have no other treatment options left. But this study suggests that patients would have the same benefits taking the already available docetaxel.
Dr Simon Crabb, a Cancer Research UK-funded prostate cancer expert, said that over the next few months the National Institute for Health and Care Excellent (NICE) will be revaluating data to see if abiraterone could be used more widely in prostate cancer patients, which could give them a second treatment option.
Crabb said that abiraterone and docetaxel have different side effects and patients should be advised on which one to take according to their needs. For example, evidence shows abiraterone is slightly kinder than docetaxel but has to be taken for a much longer period time. Docetaxel is only taken for 18 weeks.
“It is important that patients are fully informed about the side effects of each drug if, in the future, they are given a choice between treatments,” said Crabb.
“If abiraterone is to be licenced by NICE for this patient group then we need to further investigate the long-term health implications that it has on the heart and bones.
“The next step in improving treatment for men with prostate cancer that has spread would be to see if these two drugs can be used together to produce even better results.”
Abstract LBA31_PR submitted to ESMO 2017 Congress: Adding abiraterone acetate plus prednisolone (AAP) or docetaxel for patients (pts) with high-risk prostate cancer (PCa) starting long-term androgen deprivation therapy (ADT): directly randomised data from STAMPEDE