A study looking at circulating tumour cells in men having treatment for advanced prostate cancer (CTC-STOP)

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We know it’s a worrying time for people with cancer, we have information to help. If you have symptoms of cancer contact your doctor.

Read our information about coronavirus and cancer

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

Cancer type:

Cancer spread to the bone
Prostate cancer
Secondary cancers

Status:

Closed

Phase:

Phase 3

This study is looking at circulating tumour cells (CTCs) to see if it can help doctors decide when to change treatment for prostate cancer. CTCs are tumour cells that have broken away from prostate cancer and are circulating in the blood.

It is for men with advanced prostate cancer that has spread to the bones after treatment with hormone therapy Open a glossary item

More about this trial

One of the main treatments for prostate cancer is hormone therapy. But after some time, prostate cancer may spread to other parts of the body, such as the bones. This is castration resistant prostate cancer. 

You can have treatment with chemotherapy if hormone treatment is no longer working (castration resistant prostate cancer). You usually have a drug called docetaxel. This can help you for some time, but the cancer may start to grow again. When this happens, you usually stop docetaxel and start another drug called cabazitaxel

Doctors are looking for new ways to find out when docetaxel stops working. In this study, they will test blood samples to look for circulating tumour cells. 

Researchers know that small parts of prostate cancer can break away and travel in the bloodstream. These are called circulating tumours cells (CTCs). Doctors think that by finding out how many CTCs there are in the blood, they will be able to tell when docetaxel stops working. 

Everyone taking part in this study has 1 of the following: 

  • docetaxel until doctors think the treatment is no longer working (standard care)
  • docetaxel until the number of CTCs indicate, and your doctor agrees, that the treatment is no longer working (CTC-guided group)

The main aim of this study is to find out if CTCs can help doctors decide when to stop docetaxel in men with castration resistant prostate cancer. 

Who can enter

The following bullet points list the entry conditions for this study. Talk to your doctor or the study 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 study if you are a man and all of the following apply.

  • You have adenocarcinoma of the prostate that has spread to the bones after treatment with hormone therapy (castration resistant prostate cancer)
  • You have at least 2 new areas of cancer spread in the bones, or your PSA level Open a glossary item is increasing. Your doctor will check for this  
  • Doctors have tested your blood for circulating tumour cells (CTCs) and found at least 5 CTCs in 7.5 ml of blood. Your doctor can tell you about this
  • You have had treatment with abiraterone or enzalutamide and you have stopped it because your cancer got worse (disease progression)  
  • You are willing to have treatment with drugs that lower the amount of the hormone androgen such as degarelix, unless you have had surgery to remove both testicles (orchidectomy
  • You have satisfactory blood tests results     
  • You are well enough to carry out your normal activities, apart from heavy physical work (performance status of 0 or 1)
  • You are at least 18 years old  
  • You are willing to use reliable contraception during treatment and for a year afterwards if there is any possibility you can father a child 

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

Cancer related

  • You have a rare type of prostate cancer called small cell prostate cancer
  • Your cancer is pressing on the spinal cord (spinal cord compression Open a glossary item) and you need to have treatment with surgery or radiotherapy 
  • Your cancer has spread to other parts of the body, apart from the bones
  • Your cancer has spread to the brain or the membranes that surround the brain (carcinomatous meningitis
  • You have had chemotherapy after stopping hormone therapy
  • You have had hormone therapy in the past 28 days, apart from Zoladex or other similar drugs (luteinizing hormone blockers)
  • You still have moderate or severe side effects from previous anti cancer treatment, apart from hair loss, low levels of red blood cells or any other side effect that doctors think was caused by anti androgen Open a glossary itemtreatment
  • You have had radiotherapy in the last 4 weeks (2 weeks if it was one radiotherapy treatment to help with symptoms)   
  • You have had another cancer in the past 2 years apart from early bladder cancer or  basal or squamous cell skin cancer that have been successfully treated

Medical conditions

  • You have had an experimental treatment as part of another clinical trial in the last 3 weeks 
  • You take drugs that affect some enzymes called CYP3A. Your doctor can tell you about this 
  • You have heart problems such as heart failure or you have had a heart attack in the last 12 months  
  • You have had a stroke in the last 3 months
  • You have had a blockage in a vein or artery that carries blood from the heart to the lungs in the last year (pulmonary thromboembolism) 
  • You have had an infection that needed treatment in the last 3 months
  • You are sensitive to docetaxel, cabazitaxel or anything they contain 
  • You have any other serious medical condition that the trial team thinks could affect you taking part

Other

  • You are having the yellow fever vaccine 

Trial design

This is an international phase 3 trial. The researchers hope that around 1178 people worldwide will take part.

This trial is randomised. You are put into 1 of the following treatment groups by computer:

  • docetaxel until doctors think the treatment is no longer working (standard care)
  • docetaxel until the number of CTCs indicate, and your doctor agrees, that the treatment is no longer working (CTC-guided group)

Neither you nor your doctor are able to decide which group you are in.

CTC-STOP trial diagram

Everyone taking part in the study has docetaxel as a drip into a vein, every 3 weeks. It takes about 1 hour each time you have it. This is the usual treatment for people with advanced prostate cancer.

Standard care
You see the doctor regularly while you are having docetaxel. You have blood tests and scans (standard tests) to see how well the treatment is working.  

You continue to have docetaxel for as long as your doctor thinks it is helping you. This can be for up to 8 months. You stop having docetaxel if doctors think the treatment is no longer working. You then may be able to have cabazitaxel.  

CTC-guided group
You see the doctor and have standard tests. You also have blood tests to check the number of circulating tumour cells (CTCs). 

Doctors look at the standard tests and the number of CTCs to see how well the treatment is working. You: 

  • have docetaxel for as long as the amount of CTCs show that the treatment is working
  • stop docetaxel if the amount of CTCs shows (and your doctor agrees) that the treatment is no longer working  

You may be able to have cabazitaxel after stopping docetaxel. Your doctor can tell you more about this. 

Quality of life 
The research team might ask you to complete a quality of life questionnaire before each chemotherapy treatment. 

The questionnaire asks about how you have been feeling and about any side effects you have had. You don’t have to agree to this if you don’t want to. You can still take part in this study. 

Tissue sample 
The trial team will ask to use a tissue sample of your cancer that was taken either when you were diagnosed or during surgery. 

Doctors may also ask you to have extra bone marrow biopsies:

  • on the 1st day you have docetaxel 
  • before you start cabazitaxel 
  • at end of cabazitaxel

You don’t have to agree to the extra bone marrow biopsies if you don’t want to. You can still take part in this study.

Hospital visits

You see a doctor and have some tests before taking part. These tests might include: 

During the trial, you see the trial doctor before each chemotherapy treatment. This is for blood tests and a physical examination. This would also happen if you weren’t taking part in this study. 

You have a bone scan and a CT scan or MRI scan. Your doctor can tell you how often you have the scans. It depends on the standard of care at your local hospital. This continues for as long as the treatment is helping you and the side effects aren’t too bad. 

When you finish treatment, you see the trial doctor after a month. You then see or speak with the trial team every 3 months

Side effects

The trial team monitors you while you are having treatment and between treatments. They will give you a phone number to call them if you are worried about anything. 

The trial team will let you know about the possible side effects before you start treatment. 

Docetaxel and cabazitaxel are 2 common treatments for prostate cancer. We have information about the 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

Professor Johann de Bono

Supported by

Institute of Cancer Research (ICR)
Janssen Diagnostics
Menarini Silicon Biosystems
Movember Foundation
National Institute for Health Research (NIHR)
Prostate Cancer UK
Sanofi

Questions about cancer? Contact our information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:

14895

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

Over 60,000 cancer patients enrolled on clinical trials in the UK last year.

Last reviewed:

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