A trial of atezolizumab and trastuzumab emtansine for breast cancer (ASTEFANIA)

Cancer type:

Breast cancer




Phase 3

This trial is looking at atezolizumab with trastuzumab emtansine after surgery to remove breast cancer. 

It is for people with breast cancer that has a large number of the HER2 Open a glossary item protein (HER2 positive).

More about this trial

Trastuzumab emtansine is a combination of trastuzumab and emtansine. Doctors use it to treat HER2 positive breast cancer. 

Trastuzumab is a targeted drug Open a glossary item called a monoclonal antibody (MAB). It works by attaching to the HER2 protein on the surface of the cancer cells. Emtansine is a chemotherapy. Trastuzumab delivers emtansine to the cancer. When emtansine is in the cancer cell it destroys it. 

Atezolizumab is an immunotherapy. It works by stimulating the immune system Open a glossary item to kill cancer. Doctors use it for many different cancers including triple negative breast cancer

Researchers think that combining atezolizumab with trastuzumab emtansine might work well for HER2 positive breast cancer. This trial aims to find this out. 

There are 2 treatment groups in this trial:

  • half the people have trastuzumab emtansine and a dummy drug (placebo Open a glossary item)
  • half the people have trastuzumab emtansine and atezolizumab

The aims of this trial are to find out:

  • how well the combination of trastuzumab emtansine and atezolizumab works
  • what the side effects are
  • what happens to the drugs in the body and the affect they have on it
  • how it affects quality of life Open a glossary item

Who can enter

The following bullet points are a summary of the entry conditions for this trial. Talk to your doctor or the trial team if you are unsure about any of these. They will be able to advise you. 

Who can take part

You may be able to join this trial if all of the following apply. You:

  • have invasive breast cancer that is more than 1cm across
  • have cancer that has a large number of HER2 protein (HER2 positive)
  • have a tissue sample (biopsy Open a glossary item) that shows whether your cancer has the PDL-1 protein 
  • have had chemotherapy and HER2 treatment before surgery 
  • have had surgery that has removed all your cancer  
  • had your initial surgery within 3 months of going into a trial treatment group (randomisation Open a glossary item)
  • are fully active but might not be able to do heavy physical work (performance status 0 or 1)
  • have satisfactory blood test results
  • are willing to use contraception during treatment and for a time after if there is any chance you or your partner could become pregnant
  • are at least 18 years old

Who can’t take part

Cancer related
You cannot join this trial if any of these apply. You:

  • have cancer that has spread to another part of the body
  • have cancer that has started to grow again after completing treatment before surgery
  • might be able to have radiotherapy but can’t due to another medical condition 
  • have had another cancer in the past 5 years. This is apart from successfully treated in situ carcinoma Open a glossary item of the cervix, non melanoma skin cancer Open a glossary item, early (stage 1 Open a glossary item) womb cancer and DCIS Open a glossary item
  • have had too much of an anthracycline Open a glossary item chemotherapy drug such as doxorubicin. Your doctor will know if you have had one of these drugs and if you have had too much. 
  • have already had atezolizumab or trastuzumab emtansine
  • have had previous treatment with an immunotherapy Open a glossary item drug

Medical conditions
You cannot join this trial if any of these apply. You:

  • have moderate to severe nerve damage (peripheral neuropathy Open a glossary item
  • are short of breath when resting or you need to use oxygen continuously 
  • have a heart that isn’t working well enough. You will have tests to see if it is. Or you have any other heart problem Open a glossary item that could affect you taking part.
  • have high blood pressure that isn’t controlled by medication
  • have an autoimmune disease Open a glossary item. This is apart from those where you are taking medication to replace a substance in your body. And some autoimmune diseases which your doctor will know about. 
  • have lung problems such as scarring and inflammation
  • have active tuberculosis (TB), HIV, hepatitis B or hepatitis C
  • have active liver disease or other liver problems
  • have major surgery within 4 weeks of randomisation. This is apart from your breast surgery. 
  • have an anticipated need for surgery during the trial
  • have a serious infection within 4 weeks of randomisation  
  • have had an antibiotic Open a glossary item through a drip into a vein (intravenous) Open a glossary item within 2 weeks of randomisation. For antibiotics taken by the mouth (oral Open a glossary item) it is 5 days. Unless you are taking antibiotics to prevent an infection.
  • have had a stem cell transplant Open a glossary item or an organ transplant Open a glossary item
  • have had treatment as part of another clinical trial Open a glossary item within 28 days of randomisation 
  • have taken medication that stimulates the immune system Open a glossary item within 4 weeks of randomisation
  • have had medication that damps down the immune system within 2 weeks of randomisation. Or you might need this type of medication during the trial. 
  • have any other medical condition or mental health problem that your doctor or a member of the trial team thinks could affect you taking part

You cannot join this trial if any of these apply. You:

  • are allergic or sensitive to the drugs used, any of their ingredients or how they are made. Your doctor will be able to tell you about this. 
  • have a live vaccine Open a glossary item within 4 weeks of randomisation. Or you might need a live vaccine within 5 months of finishing treatment. 
  • are pregnant or breastfeeding. Or you intend to become pregnant during treatment or within up to 7 months after finishing treatment.  

Trial design

This is an international phase 3 trial. The trial team need 1,700 people to take part with about 50 people from the UK. 

It is a randomised double blind trial. You go into 1 of 2 treatment groups. Neither you nor your doctor can choose which group you are in. And neither you nor your doctor will know which treatment you are having. During the trial your doctor will be able to find out what your treatment is, if necessary. 

The 2 groups are:

  • trastuzumab emtansine and a dummy drug (placebo)
  • trastuzumab emtansine and atezolizumab 

You have treatment once at the start of each treatment cycle Open a glossary item. Each cycle is 3 weeks long. You can have up to 14 cycles of treatment (42 weeks) as long as it is helping and the side effects aren’t too bad. 

You have trastuzumab emtansine as a drip into a vein. If you are having side effects caused by trastuzumab emtansine you might be able to change to trastuzumab. Your doctor will talk to you about this if it happens. 

You atezolizumab or the dummy drug as a drip into a vein. 

Samples for research
You give extra blood samples during the trial. The team will take these at the same time as your routine bloods if possible. 

You give a sample of tissue (biopsy) if your cancer comes back and your doctor thinks it is safe to take. 

Researchers will use these samples to:

  • look for substances (biomarkers Open a glossary item) that might show how well treatment is working
  • find out more about these treatments and how they affect the body
  • find out more about breast cancer and similar diseases

Quality of life
You fill in questionnaires:

  • before you start treatment
  • during treatment 
  • a month after finishing treatment then
  • every 3 months for year 1
  • every 6 months for year 2

The questions ask about:

  • your general health
  • any side effects or symptoms
  • what daily activities you can do

These are quality of life questionnaires.

Hospital visits

You see the doctor to have tests before you take part. These tests include:

  • a physical examination
  • blood tests
  • mammogram of both breasts
  • heart trace (ECG Open a glossary item)
  • heart scan (ECHO Open a glossary item or MUGA Open a glossary item)

You see the doctor at regular times during treatment for bloods and to see how you are. You have a heart scan every 3 weeks. 

You see the doctor within a month after finishing treatment and then:

  • every 3 months for year 1 and year 2
  • every 6 months for years 3, 4 and 5
  • then every year for up to 10 years

You have a mammogram of both breasts at least once a year. 

You have a heart scan every 3 months for 2 years then:

  • every 6 months for 3 years and then
  • every year

Side effects

The trial team monitor you during treatment and afterwards. Contact your advice line or tell your doctor or nurse if any side effects are bad or not getting better. 

Atezolizumab can affect the immune system. It may cause inflammation in different parts of the body. This can cause serious side effects. They could happen during treatment, or some months after treatment has finished. Rarely, these side effects could be life threatening.
If you have any of these side effects tell your doctor or nurse as soon as possible. You should tell them that you are on or have been on an immunotherapy.


The most common side effects of atezolizumab and some of trastuzumab emtansine are:

Other most common side effects of trastuzumab emtansine are:

We have more information about atezolizumab and trastuzumab emtansine and their side effects.

We have information about trastuzumab.

Your doctor or a member of the trial team will tell you about the possible side effects of all the treatments before you agree to take part. 



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.

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Chief Investigator

Dr Duncan Wheatley

Supported by


If you have questions about the trial please contact our cancer information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:


Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Deborah wanted to help other breast cancer patients in the future

A picture of Deborah

“Deborah agreed to take part in a trial as she was keen to help other cancer patients in the future. "If taking part in a trial means others might be helped then I’m very happy with that."

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