A trial to find out if more people with bowel cancer could have cetuximab and panitumumab (ARIEL)

Cancer type:

Bowel (colorectal) cancer
Colon cancer
Secondary cancers




Phase 4

This trial is looking at biomarkers Open a glossary item to see if cetuximab and panitumumab could help more people. 

It is for people who have bowel cancer:

Depending on the levels of biomarkers, you may have treatment as part of this trial.

More about this trial

Cetuximab and panitumumab are targeted cancer drugs Open a glossary item called monoclonal antibodies. They work by blocking signals that tell cancer cells to divide and grow. They attach to a specific protein called epidermal growth factor receptor (EGFR) found on the surface of some cancer cells. You might have them to treat bowel cancer that has spread elsewhere in the body. 

Researchers know that these types of drugs don’t work as well for bowel cancer that starts on the right side. Doctors are looking for ways to improve treatment for this group of people. 

They are running this trial to see if doing some extra tests on cancer cells can help. The extra tests measure the levels of 2 biomarkers Open a glossary item. These are called AREG and EREG. We know from research that cetuximab and panitumumab work best for people whose bowel cancer cells have high levels of these biomarkers. To measure the biomarkers, researchers are using tissue samples. 

The main aims of this trial are to find out if:

  • it is possible to measure the levels of these 2 biomarkers 
  • high levels of biomarkers mean that adding cetuximab or panitumumab could improve treatment

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 the registration part of the trial if all of the following apply. You:

  • have adenocarcinoma Open a glossary item of the bowel (colon) that started on the right side. Your doctor will know this.
  • have cancer that has spread elsewhere in the body or you can’t have surgery to remove cancer that has grown into surrounding tissues
  • have bowel cancer that has a normal RAS gene 
  • have cancer that your doctor can measure on a scan
  • have satisfactory blood test results 
  • are well enough to have trial treatment 
  • have a sample of cancer tissue available for the trial team to do some tests on 
  • are at least 18 years old 

To have the treatment in this trial all of the following must apply. You:

  • must be registered for this trial
  • have high levels of at least one of two markers called AREG and EREG in your bowel cancer cells. Your doctor tests a sample of cancer tissue to check this.
  • have a normal RAS gene in your bowel cancer cells 
  • have cancer that your doctor can measure on a scan  
  • are up and about for more than half the day, you can look after yourself but might not be able to work (performance status 0, 1 or 2)
  • are well enough to have combination chemotherapy alongside cetuximab or panitumumab
  • are willing to use reliable contraception during the trial and for a period after if there is any chance you or your partner could become pregnant

Who can’t take part

You cannot join the registration part of the trial if any of these apply. You:

  • have a change in the RAS gene in your bowel cancer cells 
  • have had already had chemotherapy for bowel cancer that has spread to another part of the body 
  • have already had cetuximab, panitumumab or a similar drug 
  • have had another cancer in the past that the trial team think could affect you taking part in this trial

You cannot have the treatment in this trial if any of the following apply. You:

  • have had more than one cycle of chemotherapy Open a glossary item since you were registered to join the trial 
  • are allergic to irinotecan, oxaliplatin, fluorouracil (5FU) or anything they contain 
  • have had scarring on the lungs or active inflammation of the lungs (pneumonitis Open a glossary item
  • have had inflammation of the front part of your eye (cornea) or severe dry eye
  • have had a severe skin reaction in the past and having cetuximab or panitumumab could make it worse. Your doctor will know this. 
  • have had a live vaccination Open a glossary item within 4 weeks of joining a treatment group. Please note that the approved COVID-19 vaccines are allowed as they aren’t a live vaccine.
  • are pregnant or breastfeeding

Trial design

This phase 4 trial is taking place in the UK. The trial is in 2 parts:

  • registration 
  • treatment

The team need about 440 people to join the registration part of the trial. Of those they think about 162 will have high levels of the biomarkers Open a glossary item and will be suitable for trial treatment. 

Registration (part 1)
The researchers measure the levels of 2 biomarkers called AREG and EREG. To do this they use tissue samples from when you were diagnosed. 

Having high levels of one or both markers means that you might be suitable to join the treatment part of the trial.

You can’t join the treatment part if you have low levels of both of these tumour markers. Your doctor will talk to you about other treatment options. 

Treatment (part 2)
This part of the trial is randomised. A computer puts you into a treatment group. There are 2 groups. You have 1 of the following:

  • standard chemotherapy (group 1)
  • standard chemotherapy and cetuximab or panitumumab (group 2)

You have treatment for as long as it is working, the side effects aren’t too bad and you and your doctor wish you to continue. This will be for at least 16 weeks. 

Chemotherapy (group 1 and group 2)
Everyone has chemotherapy. This is the treatment you would have even if you didn’t join the trial. 

In this trial you have one of the following combinations of chemotherapy:

Your doctor will talk to you about which combination they think is best. 

You have chemotherapy every 2 weeks. Each 2 week period is called a cycle of treatment. Open a glossary item You have all these drugs as a drip into a vein. On the first day of each treatment cycle you have:

  • oxaliplatin or irinotecan
  • folinic acid
  • fluorouracil (5FU)

You have 5FU as a continuous infusion over 2 days. You have it through a small pump. You carry the pump on a belt or in a small bag. You can go home with the pump. The nurses will tell you how to look after it. It is disconnected on the third day. 

Group 2
In group 2 you have chemotherapy as described above. You also have cetuximab or panitumumab. Your doctor decides whether you should have cetuximab or panitumumab. They’ll talk to you about this. 

You have cetuximab or panitumumab once every 2 weeks. You have them as a drip into a vein. You have this on the same day as you have chemotherapy. Cetuximab takes up to 2 hours each time. Panitumumab takes up to an hour each time. 

Quality of life
The trial team ask you to fill out a questionnaire:

  • before you start treatment
  • at set times during treatment

The questionnaire asks about side effects and how you’ve been feeling. This is called a quality of life study.

Hospital visits

You see the doctor and have some tests before you can join the trial. These include:

  • blood tests 
  • a CT scan (unless you have had a recent one)

You have regular blood tests and check ups with the trial team during treatment. This is to see how you are getting on. This also includes an appointment at 1 year after joining a treatment group. 

You have a CT scan:

  • when you start treatment
  • at 8 weeks 
  • at 16 weeks

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. 
The most common side effects of cetuximab and panitumumab include:

  • skin rash, dry skin and nail problems
  • low levels of magnesium in the blood
  • a mild allergic reaction. This can cause a skin rash, itching, swelling of the lips, face or throat, breathing difficulties, fever and chills. Your nurse will give you medicines beforehand to try to prevent a reaction.

The trial team will talk to you about the possible side effects of treatment. 

We have more information about:


Milton Keynes

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 Jenny Seligmann
Professor Richard Adams

Supported by

University of Leeds
National Institute for Health Research (NIHR) Efficacy and Mechanism Evaluation (EME) Programme

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.

Wendy took part in a new trial studying the possible side effect of hearing loss

A picture of Wendy

"I was delighted to take part in a clinical trial as it has the potential to really help others in the future.”

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