A study of ulipristal acetate to prevent breast cancer (BC-APPS1)

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

Cancer type:

Breast cancer





This study is for women who have a moderate to high risk of developing breast cancer. 

More about this trial

Women can take tamoxifen or raloxifene to reduce the risk of developing breast cancer. But due to the side effects of these drugs few women take them. So researchers are looking for other medications to prevent breast cancer.

Progesterone is one of the female sex hormones. It is known to have a role in the development of breast cancer. Researchers think blocking the action of progesterone might help prevent breast cancer developing.

Ulipristal acetate (UA) is a drug that is already used to block progesterone. Doctors use it to treat uterine fibroids (a benign Open a glossary item  tumour of the womb).

Researchers think UA may be able to help prevent breast cancer. And it doesn’t have the same side effects as tamoxifen or raloxifene.

In this study women will take UA for a short time. The researchers will take scans Open a glossary item and samples of breast tissue. They want to look for changes in the scans and tissue that might show UA can help prevent breast cancer.

The aim is to find what affect UA has on the breast tissue of women who have a moderate to high risk of developing breast cancer. 

Who can enter

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

You may be able to join this study if you are female and prepared to travel to the University of South Manchester NHS Trust and

  • You are known to have the BRCA 1 Open a glossary item or BRCA 2 Open a glossary item gene change or have a moderate to high risk of developing breast cancer because of your family history
  • You are having regular periods  
  • You have satisfactory blood test results
  • Your kidneys are working well enough (your doctor will test for this)
  • You are willing to use reliable contraception before starting treatment, during treatment and for 2 weeks afterwards
  • You are between 25 and 45 years old

You cannot join this study if any of these apply. You

  • Have had breast cancer, uterine (womb) cancer, cervical cancer or ovarian cancer
  • Have had breast surgery to enlarge your breasts for example with implants
  • Are taking medication that blocks oestrogen Open a glossary item such as tamoxifen or raloxifene. You may be able to join if you stopped taking them at least 6 months ago and you are now having regular periods
  • Are having luteinising hormone blockers Open a glossary item such as goserelin or buserelin. You may be able to join if you stopped taking them at least 6 months ago and you are now having regular periods
  • Are taking steroids. You may be able to join if you stopped taking them at least a month ago and the possibility of restarting them is low
  • Are having medication that affects how your blood clots such as aspirin or warfarin, unless they have been stopped for at least 7 days and your clotting has returned to normal
  • Are taking certain medications that affects body substances called CYP enzymes
  • Have an increased risk of bleeding
  • Have severe asthma that isn’t controlled
  • Have vaginal bleeding unless it is caused by fibroids Open a glossary item
  • Are sensitive or allergic to the contrast medium Open a glossary item used for the MRI scan
  • Are unable to have an MRI scan for example you have certain types of medical clips or plates in your body or a pacemaker  
  • Are sensitive or allergic to ulipristal acetate or any of its ingredients
  • Have been breastfeeding within the past 3 months
  • Are pregnant or planning a pregnancy in the next 6 months

Trial design

This is a pilot study. The researcher needs 30 women to join.

Ulipristal acetate (UA) is a tablet you take once a day. After your next period you start taking it on the Monday on or after your period starts. You can take UA for up to 12 weeks.

You have a diary to write down any side effects you might have. You take this to every clinic appointment and give it to the researcher at your last one.

Please note it is unlikely you will have another period while taking UA. After your last dose of UA your periods should start again in about 4 weeks.

Tissue samples
The study team will take tissue samples after each MRI scan. They will use these to look at the normal breast tissue before and after UA treatment.

They will also ask your permission to store any breast tissue samples taken for future research into preventing breast cancer. You don’t have to agree to this. You can still take part in the study.

Hospital visits

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

During treatment you see the doctor every 4 weeks to see how you are.

In the week before stopping UA you see the doctor for the same tests you had at the start.

Women who have decided to have their breast removed to prevent breast cancer won’t have a vacuum assisted biopsy done.

The doctor sees you 5 weeks after stopping UA to find out if you are having any side effects. 

Side effects

Most people usually cope very well while taking ulipristal acetate (UA). The common side effects of UA are:

  • periods stopping
  • thickening of the lining of the womb
  • headaches
  • dizziness
  • pain in the breasts, tummy, joint and pelvis
  • feeling sick
  • acne
  • swelling
  • tiredness
  • increased cholesterol in the blood
  • cysts on the ovaries

You doctor will talk to you about the side effects of UA before you agree to take part in the study. 

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 Sacha Howell

Supported by

Breast Cancer Now
NIHR Clinical Research Network: Cancer
University Hospital of South Manchester (UHSM)

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

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“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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