A study looking at giving a biological therapy as well as combined chemotherapy and radiotherapy before surgery for cancer of the back passage (XERXES)

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

Cancer type:

Bowel (colorectal) cancer
Rectal cancer




Phase 1/2

This study is looking at giving the drug cetuximab as well as chemoradiation before surgery for cancer of the back passage (rectal cancer).

We know from research that cancer of the back passage (rectum) can be successfully treated with radiotherapy and chemotherapy before surgery. This combination of treatment works well for many people, but for some, the cancer comes back after a time.

A drug called cetuximab may help reduce the risk of the cancer coming back. Cetuximab is a type of biological therapy called a monoclonal antibody. Monoclonal antibodies can seek out cancer cells by looking for particular proteins on the cell’s surface.

People taking part in this study will have capecitabine chemotherapy with their radiotherapy, with or without cetuximab. The main aim of this study is to see if people do better with cetuximab, and which treatment plan works best. Researchers also hope to learn more about the safety and side effects of the combination of cetuximab, capecitabine and radiotherapy.

Who can enter

You can enter this study if

  • You have cancer of the back passage (rectum) that is called adenocarcinoma of the rectum
  • Your cancer is within 15 cm of the opening of your back passage
  • Your doctor has a sample of your cancer that can be tested at the end of the study to see if the cells are EGFR positive Open a glossary item
  • You need to have a combination of chemotherapy and radiotherapy (chemoradiation) to shrink your cancer before it can be removed with surgery
  • You are well enough to have surgery
  • You are well enough to carry out all your normal activities, apart from heavy physical work (performance status of 0 or 1)
  • You have satisfactory blood test results
  • You are willing and able to take the tablets given to you in the study correctly, and take part in all the study tests and visits
  • You are willing to use reliable contraception during the study treatment and for 6 months afterwards if there is a risk that you or your partner could become pregnant
  • You are at least 18 years old

You cannot enter this study if

  • You have any condition that would mean you couldn’t have radiotherapy, for example you have ulcerative colitis Open a glossary item, are taking sulphasalazine, have an abnormal opening in the body called a fistula Open a glossary item or areas of back passage (rectal) tissue that have stuck together
  • You have any condition that would stop you having capecitabine chemotherapy, for example a heart condition that is a cause for concern – you can check this with your doctor
  • You have already had radiotherapy to the area between your hip bones (your pelvis), or your back passage
  • You have already had chemotherapy for rectal cancer
  • You have had surgery anywhere in your pelvis, for example to remove your womb (hysterectomy) or your bladder (cystectomy)
  • You are opening your bowels more than 6 times a day, or you are unable to control your bowels and no one would be able to assess your diarrhoea (if you have a stoma Open a glossary item you can still take part)
  • You would have too much of your small bowel Open a glossary item in the way when you have radiotherapy to your back passage – you can check this with your doctor
  • The top of your cancer is above the level of the part of your spine called the sacrum – your doctor will be able to tell you this
  • You have, or are developing, a blockage (obstruction) in your bowel
  • You have an infection in your pelvis
  • You have a metal reinforcing tube (stent) in your back passage to stop the cancer blocking it off
  • You have a condition where your body does not make enough of an enzyme Open a glossary item called dihydropyrimidine dehydrogenase (you can ask your doctor about this)
  • You have a condition that would stop you absorbing tablets properly
  • Your cancer has spread to a distant part of your body, for example to your lungs, or you have had any other cancer in the last 5 years
  • You are taking medication as part of another clinical trial
  • You are pregnant or breastfeeding
  • You have any other condition that would make you unwell if you took part, or affect the results of the study - you can check this with your doctor

Trial design

This study is in 2 parts. Part 1 was completed a while ago. Part 2 is randomised. The people taking part are put into 2 groups by a computer. Neither you nor your doctor will be able to decide which group you are in.

If you are in group 1, you have cetuximab through a drip into vein, once a week for 4 weeks. You then have radiotherapy and capecitabine chemotherapy (chemoradiation) every weekday for 5 weeks. After this, you have cetuximab once a week, for 5 more weeks.

If you are in group 2 you will just have the chemoradiation.

After you finish treatment, you have your surgery as planned, which is not part of the study.

The team will also ask for permission to study the tissue removed for your diagnosis (biopsy). If you are having cetuximab in the study, the team would also like to take 2 fresh tissue samples during your first course of cetuximab. And a sample of tissue from your surgery.

Everyone will also give a number of blood samples.

Hospital visits

Before you start the study you will see the doctor and have some tests. These tests include

Everyone will come to hospital every weekday for 5 weeks for chemoradiation.

If you are having cetuximab in group 1, you will also come to the hospital once a week for 4 weeks before chemoradiation. And then once a week for 5 weeks after chemoradiation.

After your study treatment and before your surgery, you will have another MRI scan.

If you are having cetuximab, you will have an extra biopsy under local or general anaesthetic Open a glossary item

  • 4 hours after your first dose
  • About 3 weeks after this

You will give a study blood sample whenever you have a biopsy, and also

  • Before your first radiotherapy treatment, then at
  • 2 hours
  • 4 hours
  • 24 hours
  • 48 hours

Everyone taking part in the main study will see the study team for a check up at

  • 3 months
  • 6 months
  • 12 months
  • 24 months
  • 36 months

Side effects

Side effects of capecitabine include

Capecitabine may affect, or be affected by, other medication. If you take phenytoin, drugs to thin your blood, vitamin B6 (pyridoxine) or antiviral treatment you must tell your study doctor.

Side effects of cetuximab include

Side effects of rectal radiotherapy include

You can find out more about the side effects of capecitabine, cetuximab and rectal radiotherapy on CancerHelp UK.

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 R Glynne-Jones

Supported by

Experimental Cancer Medicine Centre (ECMC)
Merck Pharmaceuticals
NIHR Clinical Research Network: Cancer
University College London (UCL)

Questions about cancer? Contact our information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:

Oracle 568

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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