A trial looking at trastuzumab to reduce circulating tumour cells from breast cancer (EORTC 90091-10093; Treat CTC)

Cancer type:

Breast cancer

Status:

Results

Phase:

Phase 2

This trial was done to see if trastuzumab can lower the number of circulating tumour cells after other treatment for breast cancer. This means cancer cells that have broken away from the original cancer and gone into the bloodstream.

The women taking part had:

cancer with none or very few HER2 proteins (HER2 negative cancer)
already had surgery and chemotherapy

The trial was supported by Cancer Research UK. It was open for people to join between 2013 and 2016. The team published the results in 2018.

More about this trial

Some breast cancers produce large amounts of human epidermal growth factor receptor 2 protein (HER2). These are called HER2 positive breast cancers. And some cancers produce none or very little HER2. These are called HER2 negative breast cancers.

This trial was for people with HER2 negative breast cancer.

Trastuzumab (Herceptin) is a type of targeted cancer treatment called a monoclonal antibody. When this trial was done, doctors often used trastuzumab to treat HER2 positive cancers. But not to treat HER2 negative cancers.

Sometimes cancer cells break away from the original cancer and get in the bloodstream. These are called circulating tumour cells (CTCs). Research has shown that CTCs in the blood can increase the risk of the cancer coming back.

Researchers wanted to find out if trastuzumab could help reduce the level of CTCs in the blood.

People with HER2 negative breast cancer and CTCs were put into a treatment group at random:

half had trastuzumab
half had usual follow up and observation

The main aim of this trial was to find out if trastuzumab could reduce the level of CTCs in the blood.

Summary of results

The trial team looked at blood samples for 1,317 people with HER2 negative breast cancer. They found that 95 people had circulating tumour cells (CTCs). Of these, 63 joined the trial and were put into a treatment group:

31 had trastuzumab
32 had standard care

The team looked at how many people had CTCs in their blood, 18 months after joining the trial. They found it was 9 people:

5 who had trastuzumab
4 who had standard care

When they looked at how many people’s cancer had come back, they found it was 8 people:

4 who had trastuzumab
4 who had standard care

All trials are monitored by an independent committee called a data monitoring committee (DMC). They check to see how the trial is going. They can decide to close the trial to recruitment if necessary.

The DMC decided to close this trial earlier than planned. This is because they didn’t feel it would show that trastuzumab could reduce the level of CTCs in HER2 negative patients.

Side effects
Most people who had trastuzumab had at least one side effect. Many of these were mild or didn’t last long. They included muscle aches and pains and hot flushes.

Six people had a more severe side effect. These included a drop in white blood cells and a change in the level of certain proteins (enzymes) in the liver.

No one had any unexpected side effects.

We have more information about the side effects of trastuzumab in our Cancer drugs section.

Conclusion
The trial team concluded that trastuzumab does not decrease the level of CTCs in people with HER2 negative breast cancer.

Sometimes trials show a treatment isn’t useful for a particular group of patients. But these trials still add to our knowledge and understanding of cancer and how to treat it.

Future plans
As far as we are aware, there are not any other trials looking at trastuzumab and CTCs in HER2 negative breast cancer. But measuring CTCs in early breast cancer is something being looked at in other trials.

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.

Trastuzumab versus observation for HER2 nonamplified early breast cancer with circulating tumor cells (EORTC 90091-10093, BIG 1-12, Treat CTC): a randomized phase II trial
M Ignatiadis and others
Annals of Oncology, 2018. Volume 29, issue 8, pages 1777 – 1783.

Where this information comes 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.