The research team found that abiraterone
didn’t work as well as they’d hoped for breast cancer that has spread.
This trial was open for people to join between 2008 and 2014, and the team reported results in 2016.
About this trial
There were two parts (phases
) in this trial.
In phase 1, the first few people had the lowest dose of abiraterone. As they didn’t have any serious side effects, the next few people had a higher dose. And so on, until they found the best dose to use. This is called dose escalation.
In phase 2, everyone had the same dose of abiraterone. The dose they had
was based on the results from phase 1.
Everyone taking part had abiraterone tablets once a day. How long they had treatment depended on their individual situation.
This trial recruited 75 women with advanced breast cancer. They had all been through the menopause and had cancer that was oestrogen receptor (ER) positive, androgen receptor (AR) positive, or ER and AR positive.
- 25 women in phase 1
- 50 women in phase 2
The trial team looked at how well treatment worked for the 58 women who had treatment for at least 8 weeks.
They found that out of 18 people in phase 1, the cancer had:
- got a bit smaller in 1 person (5%)
- stayed the same in 5 people (28%)
- continued to grow in 12 people (67%)
They found that out of 40 women in phase 2, the cancer had:
- not got smaller in anyone
- stayed the same in 25 people (62%)
- continued to grow in 15 people (38%)
They looked at how many women who took part in phase 2 were living 2 years after treatment. They found it was 11 out of 50 women (22%).
They compared the results for women who had receptor positive and receptor negative cancer, and found there wasn’t much difference. The research team didn’t feel these results were good enough to recommend abiraterone was looked at in further trials.
About 4 out of 5 women (81%) who took part had at least one side effect. But many were mild or didn’t last long.
The most common side effect was low levels of blood potassium (hypokalaemia). This can be serious if not treated, but it usually goes back to normal levels with treatments such as potassium supplements.
Other side effects included:
- tiredness (fatigue)
- feeling or being sick
- shortness of breath or cough
- swelling in legs or feet (oedema)
- an increased risk of infection
The research team concluded that abiraterone did have some effect on breast cancer that had spread. But it didn’t work well enough for them to recommend that it’s looked at in further trials.
Even when a trial shows a treatment isn’t useful for a particular cancer, it adds to our knowledge and understanding. All trial results help doctors and researchers learn more about different cancers and the best way to treat them.
Where this information comes from
We have based this summary on information from the research team. As far as we are aware, the information they sent us has not been reviewed independently (peer reviewed
) or published in a medical journal yet. The figures we quote above were provided by the research team. We have not analysed the data ourselves.