A trial of plerixafor for certain cancers that have spread (CAM-PLEX)

The research team found that plerixafor can help immune cells get into pancreatic and bowel cancers.

Trial design
This trial was for people with pancreatic cancer or bowel (colorectal) cancer that had spread.

The trial was in 2 parts. 

In part 1, people had different doses of plerixafor. The first few people had the lowest dose. They didn’t have any serious side effects, so the next few people had a higher dose. And so on, until they found the best dose to give. This is called dose escalation. 

The research team used the results of part 1 to decide which dose was best to use in future studies.

In part 2, everyone had the same dose of plerixafor. This is called dose expansion.

Everyone had plerixafor continuously for 7 days, through a PICC line (peripherally inserted central line).  The line was attached to a small, portable pump.

The researchers took samples of the cancer before and after treatment. They compared the number and type of immune cells in the cancer samples.

Results
A total of 26 people joined this trial:

• 10 people had pancreatic cancer
• 15 people had bowel cancer
• 1 person had neuroendocrine cancer

24 of them went on to have treatment.

There were 17 people in part 1, the dose escalation part of the trial. They had 4 different doses of plerixafor. No one in the first 3 groups had any serious side effects. Two people who had the highest dose had some side effects. So the research team decided the 3rd dose was the one to use in future studies.

There were 7 people in part 2, the dose expansion part of the trial. They all had the 3rd dose used in part 1.

The effect on cancer cells
There are several types of cells and proteins involved when our immune system responds to cancer. These include:

• proteins called CXCR4 and CXCL12
• types of white blood cells (lymphocytes) called T cells and B cells

The results of this trial showed that, after plerixafor, there was an increase in:

• the amount of the CXCR4 protein 
• the number and activity of T cells and B cells 

How well treatment worked
The research team looked at how well treatment worked in 23 people who took part. This wasn’t the main aim of the trial. And it’s difficult to draw any firm conclusions with such small numbers of people.

They found that the cancer had:

• not got smaller in anyone
• stayed the same in 13 people
• continued to grow in 10 people

Conclusion
The research team concluded that plerixafor helped increase the number of immune system cells within pancreatic and bowel cancers.

They suggest a longer course of plerixafor is looked at in other trials, possibly alongside immunotherapy treatments. 

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 ) 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.