A trial looking at enadenotucirev with chemoradiotherapy for rectal cancer (CEDAR)

Cancer type:

Bowel (colorectal) cancer
Rectal cancer




Phase 1

This trial looked at having enadenotucirev with chemoradiotherapy for people with cancer of the back passage (rectal cancer) that was locally advanced.

Enadenotucirev is a virus treatment for cancer. You pronounce enadenotucirev as en-ad-in-oh-too-sir-ev. 

Locally advanced rectal cancer is cancer that has spread into the surrounding tissue.

Cancer Research UK supported this trial. 

The trial was open for people to join between 2019 and 2022. The team presented the results at a conference in 2023.

More about this trial

Chemotherapy with radiotherapy (chemoradiotherapy Open a glossary item) is a treatment for people with locally advanced rectal cancer. The chemotherapy helps make the cancer cells more sensitive to the radiotherapy.

Researchers were looking for ways to make chemoradiotherapy work better. They thought enadenotucirev (EnAd) might work.

EnAd is a virus. It kills cancer cells but causes very few problems to the healthy cells. It only grows in cancer cells and passes from one cancer cell to another. When it reaches healthy cells it stops growing. And so doesn’t harm any healthy cells.

People in the trial had EnAd as part of their chemoradiotherapy. 

The aims of this trial were to find:

  • the best dose of EnAd to give 
  • when to give it 
  • how often to give it
  • how well it works with chemoradiotherapy

Summary of results

13 people took part in this Phase 1 Open a glossary item trial. Everyone had EnAd with their chemoradiotherapy. 

The team wanted to look at 4 different dose schedules of EnAd. But they didn’t start anyone on the 4th dose schedule. This was because 2 people having the 3rd dose schedule had a severe side effect.

These side effects were:

  • kidney problems
  • fluid build up in the legs 

All other side effects reported were mild to moderate. The most common side effects were chills, tiredness (fatigue) and diarrhoea.

At 13 weeks the team looked at how well EnAd worked according to the dose schedule. They found that the 3rd dose schedule gave the best result. 

Of the 13 people, 2 missed 1 dose of EnAd due to having COVID-19. 

The team looked at whether the cancer had got smaller or stopped growing after the treatment for each dose schedule.

Dose schedule 1
Of the 2 people who took part they found that the cancer hadn’t shrunk or stopped growing.

Dose schedule 2
Of the 4 people who had this dose and the cancer got smaller or stopped growing for 2 of them.

Dose schedule 3
Of the 6 people who took part and the cancer got smaller of stopped growing for 3 of them.  

The team also took tissue samples and blood samples. They are continuing to look at these samples to find out more about how EnAd works. 

The team concluded that EnAd with chemoradiotherapy didn’t cause too many side effects. 

They found the 3rd dose schedule was the best and this is the one to use when doing a phase 2 trial Open a glossary item.

The team also concluded that it could help stop the cancer growing and reduce the size of the cancer and suggest further research should be done. 
Where this information comes from    
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) but may not have been published in a medical journal. The figures we quote above were provided by the research team. 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 Maria Hawkins

Supported by

Cancer Research UK
Oncology Clinical Trials Office (OCTO)
PsiOxus Therapeutics Ltd
University of Oxford

Other information

This is Cancer Research UK trial number is CRUK/17/015.

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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