A trial looking at a new drug called AZD9833 for people with breast cancer (Serena 1)

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

Cancer type:

Breast cancer
Secondary cancers




Phase 1
This trial is for people with advanced breast cancer. This means that the cancer:
  • has come back in the same place after treatment (locally recurrence)
  • has spread to other parts of the body (metastatic)
It is for people whose breast cancer cells are sensitive to the hormone oestrogen (oestrogen receptor positive or ER positive). And does not have receptors for a protein called HER2 (HER2 negative). 

More about this trial

Targeted drugs and hormone therapy are common treatments for advanced breast cancer. These treatments can work well for some time, but sometimes the cancer starts to grow again. 
Many breast cancers need the hormone oestrogen to grow. These are called oestrogen receptor positive breast cancer. Doctors think that AZD9833 can reduce the amount of oestrogen in your body and stop breast cancer from growing. This is the first time that AZD9833 will be given to people.
Everyone taking part in this trial has AZD9833. Some people have AZD9833 on its own and some have it in combination with 1 of the following:

These drugs are all targeted drugs called cancer growth blockers. They block signals that cancer cells use to divide and grow. 

Palbociclib, everolimus, abemaciclib and ribociclib are usual treatments for some types of advanced breast cancer. 

Please note: there are 14 parts to this trial. Currently, doctors are only looking for people to join the parts of the trial looking at AZD9833 and ribociclib. This is part K and L.  
The main aims of this trial are to:

  • find out the best dose of AZD9833 on its own and with other drugs
  • learn about the side effects of AZD9833

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 you are a woman and all of the following apply:
  • you have adenocarcinoma of the breast (breast cancer) that has spread to other parts of the body or has come back in the same place after treatment
  • you are post menopausal, or you have taken drugs that stop the ovaries from making hormones (LH blockers) for at least 4 weeks 
  • your cancer is sensitive to the hormone oestrogen (ER positive) and does not have receptors for the HER2 protein (HER2 negative)
  • doctors think that you can’t have treatment to try to cure your cancer
  • your cancer got worse (progressed) during or after treatment that reached your whole body (systemic) 
  • you are well enough to carry out all your normal activities, apart from heavy physical work (performance status of 0 or 1) and this hasn’t changed during the last 2 weeks 
  • you have satisfactory blood test results 
  • your heart is working well 
  • you can swallow and absorb tablets 
  • you are at least 18 years old 
  • you are willing to use reliable contraception during treatment and for at least a month afterwards, if there is any chance that you could become pregnant 
Who can’t take part
You cannot join this trial if any of these apply. 
Cancer related 
  • have had more than 2 types (regimens) of chemotherapy for advanced breast cancer
  • have had chemotherapy, an experimental drug or any other cancer drug in the last 2 weeks 
  • have had radiotherapy to help with symptoms in the last week (4 weeks if it was radiotherapy to a large part of your body, including the bone marrow) 
  • still have moderate or severe side effects from previous treatment, apart from hair loss
  • have cancer spread in your brain or spinal cord, unless you have had treatment for it and you haven’t taken steroids in the last month
Medical conditions
You cannot join this trial if any of these apply. You:
  • take drugs or herbal supplements that affect certain enzymes called CYP3A and CYP2B, or that affect your heart (your doctor can tell you more about this) 
  • are going to have, or have had a major operation in the last month
  • have heart problems such as hypertension that isn’t controlled, angina that isn’t stable, or you have had a heart attack in the last 6 months 
  • have a high risk of bleeding 
  • have problems with your digestive system such as sickness that isn’t controlled 
  • have an infection and need to have antibiotics 
  • have hepatitis B or hepatitis C 
  • have HIV  
  • have any other serious medical condition that the trial team think could affect you taking part
You cannot join this trial if any of these apply. You:
  • are involved in the planning or running of this trial 
  • are sensitive to AZD9833 or any of the drugs used in this trial or anything they contain

Trial design

This is an international phase 1 trial. Researchers hope that up to 520 people worldwide will agree to take part.

There are 14 parts to this trial. The following parts are open to recruitment:

  • part K
  • part L

Part K
Researchers hope that around 48 people will agree to take part in part K. Everyone has AZD9833 and ribociclib. You have both treatments as tablets that you take in the morning, with or without food. 

Some people will also have a type of hormone therapy called anastrazole. 

Your treatment continues for as long as it is helping you and the side effects aren’t too bad.

Part L
Researchers hope that around 48 people will agree to take part in part L. 

Everyone joining part L has the same treatment as part K. Researchers want to see how well this treatment combination works in a large number of people. 

Tissue and blood sample 
The trial team ask you for a tissue sample of your cancer. This can be from when you had a biopsy or surgery to remove the cancer (archival tumour sample). 

They may also ask you to give up to 3 new tissue samples (fresh tumour biopsies). You have them:

  • before the start of treatment
  • during treatment 
  • if your cancer gets worse

You don’t have to agree to give new tissue samples if you don’t want to. You can still take part in this trial. 
You also have extra blood tests as part of this trial. Where possible, you have them at the same time as your routine blood tests. Doctors want to:

  • look for different substances (markers) that can help to tell how well treatment might work
  • find out what happens to AZD9833 in your body

You have the extra blood tests at set times during this trial.

Hospital visits

You see a doctor and have some tests before taking part. The tests you might have include:
  • a physical examination
  • heart trace (ECG)
  • an ultrasound scan of your heart (ECHO)
  • blood tests 
  • urine tests
  • CT scan or MRI scan 
  • bone scan 
  • an eye examination
  • a test of your heart called a holter test Open a glossary item 

During treatment, you see the trial team regularly. How often you see them depends on when you join the trial. 
You have regular tests during treatment. The tests you have include blood tests, physical examinations, and heart traces. 
You also have a CT scan or MRI scan every 8 weeks, for six months. You then have a CT scan or MRI scan every 3 months. This continues for as long as the treatment is helping you and the side effects aren’t too bad. 
When you finish treatment, you might see the trial team after one week, 2 weeks and a month. You have blood tests, a heart trace and a physical examination. You may continue to see the trial team afterwards if you still have side effects from treatment.

Side effects

AZD9833 is a new drug and there might be side effects that we don’t know about yet. Doctors think that the side effects of AZD9833 include:
  • high blood pressure and changes to the way your heart works 
  • a build up of fat in the cells of your liver and lungs which may cause difficulty breathing, tummy (abdominal) pain, and yellow colouring of your skin and whites of your eyes
  • shaking (tremor), agitation and fits (seizures)
  • changes in the size and the lining of your ovaries and womb 
  • changes to your eyesight such as seeing shadows 

We have information about the possible side effects of:

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 Richard Baird

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.

Around 1 in 5 people take part in clinical trials

3 phases of trials

Around 1 in 5 people diagnosed with cancer in the UK take part in a clinical trial.

Last reviewed:

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