A trial of atezolizumab and chemotherapy for triple negative breast cancer that has spread (IMpassion131)

Please note - this trial is no longer recruiting patients. We hope to add results when they are available.

Cancer type:

Breast cancer




Phase 3

This trial is for people whose breast cancer has grown into surrounding tissue or it has spread elsewhere in the body.

Triple negative breast cancer are cancers without receptors for:

  • oestrogen
  • progesterone
  • HER2 Open a glossary item

More about this trial

Chemotherapy is one of the usual treatments for triple negative breast cancer that has spread. You might have a chemotherapy drug called paclitaxel. Doctors are always looking for way to improve treatment. In this trial, they are looking at adding a drug called atezolizumab to chemotherapy.

Atezolizumab is a type of immunotherapy. It blocks a protein called PD-1. This triggers the immune system Open a glossary item to attack and kill cancer cells.

Doctors hope that adding atezolizumab to paclitaxel can improve the way it works.

In this trial, some people have paclitaxel and atezolizumab. And some have paclitaxel and a dummy drug (placebo Open a glossary item).

The main aims of this trial are to:

  • find out how well atezolizumab and paclitaxel work
  • learn more about the side effects

Who can enter

The following bullet points list 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.


  • have triple negative breast cancer that has grown into surrounding tissue and it isn’t possible to have surgery to remove it or it has spread elsewhere in the body
  • are suitable to have paclitaxel chemotherapy
  • have cancer that the doctor can measure on a scan
  • have a tissue sample (biopsy Open a glossary item) available for the trial team to do some tests on
  • are well enough to carry out all your normal activities, apart from heavy physical work (performance status 0 or 1)
  • have satisfactory blood test results
  • are willing to use reliable contraception during the trial and for at least 6 months after treatment finishes if there is any chance you or your partner could become pregnant
  • are at least 18 years old

Who can’t take part
You cannot join this trial if any of these apply.

Cancer related

  • have had chemotherapy, a targeted cancer drug or hormone therapy Open a glossary item for breast cancer unless you had chemotherapy for early breast cancer
  • have cancer that has spread to the brain or spinal cord or surrounding tissues unless it has been treated, it isn’t causing symptoms and you are no longer having steroid Open a glossary item treatment
  • have spinal cord compression Open a glossary item that hasn’t been treated with surgery and/or radiotherapy or you have had treatment in the past for spinal cord compression, but the condition is no longer stable
  • have a lot of pain caused by your cancer that isn’t well controlled with medication
  • have had treatment with an experimental drug in the 30 days before starting the treatment in this trial
  • have had another cancer in the last 5 years apart from carcinoma in situ (CIS Open a glossary item) of the cervix, basal cell skin cancer Open a glossary item and squamous cell skin cancer Open a glossary item or early cancer of the womb that has been successfully treated

Medical conditions

  • have problems with your heart, such as a heart attack in the last 3 months, angina that is not well controlled, an abnormal rhythm of your heart, congestive heart failure or the left side of your heart can’t pump blood around your body very well
  • have an autoimmune disease Open a glossary item such as rheumatoid arthritis, inflammatory bowel disease or multiple sclerosis apart from type 1 diabetes or thyroid problems that are controlled by medications
  • have a serious infection that needs to be treated with antibiotics in the 2 weeks before joining the trial
  • have had major surgery within 4 weeks of joining the trial
  • have a collection of fluid around your lung, heart or tummy (abdomen) that isn’t well controlled with treatment
  • have high levels of a mineral in your blood called calcium
  • have had a stem cell transplant Open a glossary item with somebody else’s cells or an organ transplant
  • have a lung condition called pneumonitis
  • have an active tuberculosis (TB) infection
  • have already had a targeted cancer drug that targets PD-1, PD-L1 or CD137  
  • have had treatment that dampens down your immune system Open a glossary item such as steroids unless it is a low dose
  • have had a drug that stimulates your immune system for example, interferon or interleukin within 4 weeks of joining the trial or it hasn’t completely cleared your body
  • have HIV
  • have hepatitis B or hepatitis C
  • have any other serious medical condition or mental health problem that the trial team think could affect you taking part


  • have had a severe allergic reaction to or are sensitive to monoclonal antibodies Open a glossary item
  • are allergic to any of the ingredients in atezolizumab
  • have had a live vaccination Open a glossary item the 4 weeks before joining the trial
  • have veins that are very difficult to insert a cannula Open a glossary item into
  • have a problem with drugs or alcohol
  • are sensitive to paclitaxel
  • are planning on becoming pregnant, pregnant or breastfeeding

Trial design

This phase 3 trial is taking place worldwide. The researchers hope 495 people will take part including 20 in the UK.

It is a randomised trial. You are put into treatment groups by a computer. Neither you nor your doctor can decide which group you are in. And neither of you will know which group you are in. This is called a double blind trial.

You have 1 of the following:

  • paclitaxel and atezolizumab
  • paclitaxel and a dummy drug (placebo Open a glossary item)

You are 2 times more likely to have atezolizumab.

You have treatment in cycles. Each treatment period is 4 weeks. You have all your treatment as a drip into a vein.

The first day of each treatment cycle is called day 1. You have atezolizumab or the dummy drug on:

  • day 1
  • day 15

This takes about an hour each time.

You have paclitaxel on:

  • day 1
  • day 8
  • day 15

This takes about an hour each time.

You have treatment for as long as it is working and the side effects aren’t too bad

Quality of life
The trial team will ask you to fill out a questionnaire before you start treatment and at set times during treatment. The questionnaire will ask about side effects and how you’ve been feeling. This is called a quality of life study Open a glossary item.

Samples for research
You give some extra blood samples during treatment. You give the samples at specific times and the trial team will give you more information about this. They plan to use the samples to:

  • see how well the treatment is working
  • find out what happens to the drugs in the body
  • look for biomarkers Open a glossary item to predict who will benefit from treatment

The doctors will ask permission to collect 2 extra tissue samples. You do not have to agree to give these samples if you don’t want to. You can still take part in the trial.

Hospital visits

You see a doctor and have some tests before you can take part. These include:

During treatment, each hospital visit takes about 3 to 5 hours. You shouldn’t need to stay overnight.

At each visit you see a doctor for a check up and blood tests.

You have a CT scan or MRI scan:

  • every 8 weeks for 1 year
  • and then every 3 months until your cancer gets worse

When you finish treatment, you see the trial team after 1 month.

Follow up
When you finish treatment the trial team will contact you every 3 months to see how you are getting on. They might phone you or see you at routine hospital appointments. Or they might check your medical notes.

Side effects

The trial team monitor you during the time you have treatment and you’ll have a phone number to call them if you are worried about anything.

The most common side effects of atezolizumab include:

  • tiredness (fatigue) and lack of energy
  • joint pain, muscle or bone pain
  • loss of appetite
  • diarrhoea
  • shortness of breath
  • skin rash or itchy skin
  • feeling or being sick
  • fever, chills and flu like symptoms
  • difficulty swallowing
  • changes to the liver
  • an allergic reaction or becoming over sensitive to it
  • low levels of minerals called potassium or sodium in blood
  • low blood pressure
  • thyroid gland Open a glossary item problems
  • blocked nose
  • inflammation of the bowel
  • shortness of breath
  • nerve damage resulting in possible numbness, pain, and/or difficulty with fine motor movements such as doing up buttons
  • inflammation of the lungs (pneumonitis)
  • increased risk of bruising or bleeding
  • tummy (abdominal) pain

The most common side effects of paclitaxel include:

  • a drop in blood cells causing an increased risk of infection, bleeding problems, tiredness and breathlessness
  • pain in the joints or muscles
  • numbness, tingling and burning in the hands and feet
  • feeling or being sick
  • diarrhoea
  • an allergic reaction such as skin rash or flushing
  • redness or swelling in the mouth
  • low blood pressure
  • hair loss

The trial doctor will explain all the possible side effects before you join the trial.

We have more information about:

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

Professor David Miles

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.

Harriet wanted to try new treatments

Picture of Harriet

“I was keen to go on a clinical trial. I wanted to try new cancer treatments and hopefully help future generations.”

Last reviewed:

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