A trial looking at capecitabine with or without bevacizumab for colorectal cancer (QUASAR 2)

Cancer type:

Bowel (colorectal) cancer
Colon cancer
Rectal cancer




Phase 3

This trial compared capecitabine and bevacizumab with capecitabine alone for bowel (colorectal) cancer. It was for people whose cancer was thought to have a high risk of spreading to another part of the body. 

More about this trial

Surgery is a common treatment for bowel cancer. And doctors often treat colorectal cancer with chemotherapy after surgery to help stop the cancer coming back. 

Two drugs commonly used are 5FU and capecitabine (Xeloda). Capecitabine is similar to 5FU but is a tablet rather than an injection.

Doctors thought the combination of capecitabine and bevacizumab (Avastin) might be better at stopping the cancer coming back. But they weren’t sure. 

Bevacizumab is type of biological therapy called a monoclonal antibody.

In this trial, some people had capecitabine. And some had capecitabine and bevacizumab. 

The aim of the trial was to find out which was best at stopping colorectal cancer coming back after surgery. And to find out more about the side effects. 

Summary of results

The team found that the combination of bevacizumab and capecitabine wasn’t any better than capecitabine alone.

This phase 3 trial was randomised. 1,952 people took part and were put into 1 of 2 treatment groups:

  • 977 had capecitabine 
  • 975 had capecitabine and bevacizumab

QUASAR2 Trial Diagram

Of these the researchers were able to look at the results of 1,941 people:

  • 968 had capecitabine 
  • 973 had capecitabine and bevacizumab

The team looked at the number of people who were alive and had no sign of cancer 3 years after treatment. They found the number was similar in both groups. It was:

  • 712 people in the capecitabine group
  • 704 people in the capecitabine and bevacizumab group

The most severe side effects of the combination of capecitabine and bevacizumab were:

  • hand and foot syndrome 
  • diarrhoea
  • high blood pressure
  • protein in the urine
  • problems with wound healing

The team also looked at substances in blood and tissue samples (biomarkers Open a glossary item) that could tell them how well the treatment was working. They found that a small group of people with certain biomarkers might benefit from having bevacizumab with capecitabine after surgery to remove their bowel cancer.

The trial team concluded that combining bevacizumab with capecitabine didn’t benefit people after surgery to remove their cancer. But for a small group of people whose cancer cells have a certain biomarker there might be a benefit. And this would be worth studying further.  

We have based this summary on information from the research team. The information they sent us has been reviewed by independent specialists (peer reviewed Open a glossary item) and published in a medical journal. The figures we quote above were provided by the trial team who did the research. We have not analysed the data ourselves.

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 David Kerr 

Supported by

Cancer Research UK
Experimental Cancer Medicine Centre (ECMC)
NIHR Clinical Research Network: Cancer
University of Oxford
Australasian Gastro-Intestinal Trials Group (AGITG)


Other information

This is Cancer Research UK trial number CRUKE/02/017.

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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