A trial looking at everolimus, exemestane and capecitabine for advanced breast cancer (BOLERO 6)

Cancer type:

Breast cancer

Status:

Results

Phase:

Phase 2

This trial looked at 3 treatments for breast cancer that had spread outside the breast. This is locally advanced or metastatic breast cancer.

It was for women after the menopause Open a glossary item . And whose breast cancer:

had receptors for the hormone oestrogen (hormone receptor positive )
didn’t have receptors for a protein called HER2 (HER2 negative )

This trial was open for women to join between 2013 and 2014, and published in 2018.

More about this trial

You might have hormone therapy for locally advanced or metastatic breast cancer. Letrozole and anastrozole are 2 drugs you might have.

But sometimes the cancer comes back or gets worse. If this happens, you might have another hormone therapy drug called exemestane. Or a chemotherapy drug called capecitabine.

Everolimus was a newer drug when the researchers did this trial. It is a targeted drug Open a glossary item called a cancer growth blocker. It works by reducing the blood supply to the cancer and slowing down the growth of the cancer.

Researchers thought adding everolimus to exemestane might improve treatment. But they weren’t sure, so wanted to find out more.

In this trial, women had 1 of the following:

everolimus
everolimus and exemestane
capecitabine

Researchers wanted to find out:

how well treatment worked
more about the side effects

Summary of results

The researchers looked at how long women lived before the cancer started to grow again. They found that everolimus and exemestane worked better than everolimus on its own. But capecitabine worked better than everolimus and exemestane.

About this trial
309 women joined this trial. They were put into 1 of 3 groups at random.

104 had everolimus and exemestane
103 had everolimus
102 had capecitabine

12152_bolero_6.png

Everyone had treatment as long as it was working and the side effects weren’t too bad.

Results
Researchers followed everyone up for an average of about 38 months. They looked at how well treatment worked.

They looked at how long women lived before the cancer started to grow again. This is called progression free survival. First, they compared everolimus and exemestane with everolimus only. They found on average, progression free survival was:

8.4 months in women who had everolimus and exemestane
6.8 months in women who had everolimus only

Then they compared everolimus and exemestane with capecitabine. They found the average length of time women lived before the cancer started to grow again was:

8.4 months in the everolimus and exemestane group
9.6 months in the capecitabine group

12152_bolero-6_1.png

These numbers showed that capecitabine worked better. But researchers say that this wasn’t what they had expected. Results of other similar trials showed that everolimus and exemestane worked better.

The researchers think there were a few reasons that capecitabine worked better. For example:

more people in the capecitabine group were younger and fitter
fewer people in the capecitabine group had 3 or more areas of cancer spread

They also say there was some missing information. For example, some women had other treatment after the trial, and some didn’t. Having other treatment can affect results. And the results were better in the capecitabine group than they were expecting.

The researchers also looked at how long women lived. This was:

23.1 months in the everolimus and exemestane group
29.3 months in the everolimus group
25.6 months in the capecitabine group

Side effects

The more serious side effects of:

everolimus and exemestane were a sore mouth, liver damage and tiredness and shortness of breath due to a drop in red blood cells (anaemia)
everolimus was liver damage and tiredness and shortness of breath caused by a drop in red blood cells (anaemia)
capecitabine was numbness, tingling, redness or soreness on the palms of the hands or soles of the feet (hand foot syndrome)

Women who had everolimus and exemestane or everolimus on its own had more problems with a sore mouth. This was a common side effect for both groups.

Conclusion
The trial team found that everolimus and exemestane worked better than everolimus. But the trial didn’t show that everolimus and exemestane worked better than capecitabine.

Instead the results showed that capecitabine worked better than expected. But researchers say it is hard to know for sure if this was the case as they weren’t able to include everyone in the final analysis.

Where 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.