A trial looking at a giredestrant for breast cancer (acelERA Breast Cancer)
Cancer type:
Status:
Phase:
This trial compared giredestrant with 
for breast cancer that had either come back after treatment or spread.
It was for people whose breast cancer cells:
- had receptors for the hormone oestrogen (
oestrogen receptor positive or ER positive cancer) - did not have receptors for the protein
HER 2 (HER2 negative cancer)
The trial was open for people to join between 2020 and 2021. The team published the results in 2024.
You pronounce giredestrant as jeer-a-das-trant.
More about this trial
Doctors often treat breast cancer that has come back or spread with hormone therapy.
Many breast cancers need the hormone oestrogen to grow. These are called oestrogen receptor (ER) positive breast cancers. Doctors hoped that giredestrant (GDC-9545) might block the oestrogen receptors. And this would stop oestrogen getting to the cancer cells and stop the cancer growing.
The trial team wanted to find out if giredestrant works better than other hormone therapies that were being used at the time.
The people in this trial were put into a treatment group at random. Half had giredestrant, and half had a different hormone therapy (the group).
People in the standard care group had either fulvestrant or an aromatase inhibitor. The doctors decided which one based on their individual situation.
The main aims of this trial were to find out:
- if giredestrant works better than other hormone therapies
- more about the side effects
- more about how treatments affect quality of life
Summary of results
The trial team were not able to say for sure whether giredestrant worked better than other hormone therapies.
Results
A total of 303 people joined this trial. They were put into one of two groups at random. There were:
- 151 people in the giredestrant group
- 152 people in the standard care group
The team also looked the results for people who had a change () in a called ESRi, and those who didn’t. Just under 4 out of 10 people (39%) had the mutation.
They looked at how long it was until the cancer came back in half the people in each group. This is called the median time.
The results showed that, for those who had giredestrant it was:
- 5.6 months for everyone in the group
- 5.3 months for those who had an ESRi gene change
- 7.2 months for those who didn’t have an ESRi gene change
And for those who had standard treatment it was:
- 5.4 months for everyone in the group
- 3.5 months for those who had an ESRi gene change
- 6.6 months for those who didn’t have an ESRi gene change
They found it was:
- 133 out of 151 people (88%) who’d had giredestrant
- 141 out of 152 people (93%) who’d had standard treatment
The differences between the groups for all these results are not big enough to say for sure whether it was due to the treatments or not. It could have been due to chance.
Side effects
Some people in each group had at least one side effect caused by the treatment:
- 70 people (47%) who had giredestrant
- 43 people (28%) who had standard treatment
Many of the side effects were mild or didn’t last long.
The most common side effects were:
- increased level of proteins called AST and ALT which can be sign of liver problems
- joint pain
- a drop in red blood cells causing tiredness and shortness of breath
- feeling sick
A few more people in the giredestrant group had each of these side effects.
A small number of those who had side effects had a more severe side effect:
- 6 people (4%) who had giredestrant
- 4 people (3%) who had standard treatment
These included:
- a drop in red blood cells causing tiredness and shortness of breath
- increased blood pressure
- increased level of
bilirubin and a protein called AST which can be sign of liver problems - bone pain
We have more information about the side effects of fulvestrant and other standard treatments in our Cancer drugs section.
Quality of life
The people taking part filled out questionnaires before, during and after treatment. These asked how people were feeling.
The results showed that many aspects were similar for the 2 groups. People in the giredestrant group had less pain and felt more able to do everyday tasks. They had a slightly higher overall quality of life score.
Conclusion
The trial team think giredestrant may be useful for breast cancer that has spread or come back. But it was hard to draw any firm conclusions because the differences between the groups were small.
They did conclude that giredestrant didn’t cause too many side effects. They suggest more trials are done.
More detailed information
There is more information about this research in the reference below.
Please note, the information we link to here is not in plain English. It has been written for healthcare professionals and researchers.
Giredestrant for Estrogen Receptor–Positive, HER2-Negative, Previously Treated Advanced Breast Cancer: Results From the Randomized, Phase II acelERA Breast Cancer Study
Miguel Martín and others
Journal of Clinical Oncology, 2024. Volume 42, issue 18, pages 2149-2160.
Where this information comes from
We have based this summary on the information in the article above. This has been reviewed by independent specialists () and published in a medical journal. We have not analysed the data ourselves. As far as we are aware, the link we list above is active and the article is free and available to view.
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.
Chief Investigator
Dr Sarah Khan
Supported by
Roche
If you have questions about the trial please contact our cancer information nurses
Freephone 0808 800 4040
