A trial looking at atezolizumab before surgery for bladder cancer (ABACUS)

Cancer type:

Bladder cancer
Transitional cell cancer




Phase 2

This trial looked at atezolizumab for people whose bladder cancer had spread beyond the inner lining of the bladder, but not to another area of the body. 

More about this trial

Invasive bladder cancer means that the cancer has grown into the bladder wall. But it has not spread to other parts of the body. Doctors often treat it with an operation to remove the bladder (a cystectomy).  

Atezolizumab is a type of targeted cancer treatment called a monoclonal antibody

Some cancer cells produce a protein called PD-L1. This protein helps the cancer cells to hide away from the immune system. Atezolizumab blocks PD-L1, so the immune system can find and kill the cancer cells. 

Doctors wanted to find out if atezolizumab is useful for people with bladder cancer who are due to have surgery to remove their bladder. 

They also looked at different proteins (biomarkers) in blood samples and genetic changes in the cells. They wanted to see if these affected how well the treatment worked.

The main aims of this trial were to find out:

  • whether atezolizumab can help reduce the size of the bladder cancer
  • whether different proteins and genetic changes affect how well treatment works
  • more about the side effects

Summary of results

The research team found that atezolizumab worked for some people with bladder cancer that had grown into the bladder wall. And they were able to look at different proteins and genetic changes.

Trial design
Everyone in this trial had bladder cancer that had grown into the muscle wall but not spread to another part of the body. They were all due to have an operation to remove their bladder (a cystectomy). They were not able to have chemotherapy before their operation, which some people with bladder cancer have. 

Everyone had either one or two cycles Open a glossary item of atezolizumab before their operation. 

A total of 95 people joined this trial. Of these:

  • 20 people had 1 cycle of atezolizumab
  • 75 people had 2 cycles of atezolizumab
  • 87 people went on to have surgery as planned

The research team looked at how well treatment worked. They found that just over 3 out of 10 people (31%) had no more signs of cancer when they had their operation. This was a bit higher than they were expecting.

Nearly 8 out of 10 people (78%) had no sign of cancer a year after treatment. This is higher than you’d expect for people who had surgery alone. 

They also looked at the immune cells, the different proteins and the genetic changes in the blood samples and cancer cells of people taking part. 

They found that the proteins (biomarkers Open a glossary item) in people’s blood samples changed when they had treatment. But genetic changes in people’s cells when they had treatment were less likely.

Treatment tended to work better in people who had a higher number of active immune cells called T cells before they started treatment.

Treatment tended to work less well in people who had an increase in 2 specific biomarkers. These are called transforming growth factor and fibroblast activation protein, and are both involved with the growth of cancer cells.

How well treatment worked was not affected by whether cancer cells produced the PD-L1 protein or not. Or by the amount of genetic changes in the cells.

Side effects
Just over half of the people who took part (52%) had at least 1 side effect. Most were mild or didn’t last long. A small number of people had more severe side effects.

The most common side effects were:

  • extreme tiredness (fatigue)
  • loss of appetite (anorexia)
  • a temporary increase of a liver protein called transaminase (which shows in a blood test but doesn’t always cause symptoms)

Having atezolizumab didn’t seem to increase the chance of having problems after surgery. Some people did have side effects or complications following their operation. But no more than you would expect. 

The research team concluded that atezolizumab did help some people with bladder cancer that has grown into the bladder wall but not spread. And that they had learnt more about treating people in this situation.

They hope that in future they may be able to use levels of certain proteins to predict who is most likely to benefit from treatment. 

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) 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 Thomas Powles

Supported by

Cancer Research UK
Experimental Cancer Medicine Centre (ECMC)
F. Hoffmann-La Roche Ltd
Queen Mary University of London

Other information

This is the Cancer Research UK trial number CRUKE/15/014.

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:

Rate this page:

No votes yet
Thank you!
We've recently made some changes to the site, tell us what you think