A study of taselisib and palbociclib for breast cancer (PIPA)

The study team found that the side effects of having taselisib with palbociclib were tolerable and manageable. This was also the case when the people taking part had it with or without hormone therapy. 
 
Study design
This was a phase 1  study. There were 78 people in the study. Everyone had the PIKC3A gene change. There were 2 parts. 

In part 1 there were 20 people. The team found the best dose of taselisib and palbociclib to give. They used this for part 2. 

There were 3 groups in part 2. 

In group 1 there were 25 people with ER positive, HER2  negative advanced breast cancer . They had palbociclib, taselisib and fulvestrant.

In group 2 there were 26 people. Some people had ER negative advanced breast cancer and some had another type of solid tumour. They had palbociclib and taselisib.

In group 3 there were 7 people with ER positive, HER2 negative advanced breast cancer. They had palbociclib, taselisib and letrozole.

Results
The study team took blood samples to see what happened to taselisib and palbociclib in the body. They found that giving the 2 drugs together didn’t affect the amount of each drug the body absorbed.  

Side effects
The team looked at the most commonly reported side effects of the 58 people in the 3 groups in part 2. They found the most commonly reported side effects were:

• a drop in blood cells 
• tiredness (fatigue)
• diarrhoea

Stopping treatment
The team looked at the reasons people stopped treatment. For this they were able to look at 77 people. Of these the number that stopped were:

• 54 of the 77 people (70%) because a scan  showed their cancer was getting worse
• 13 of the 77 people (17%) because an examination or blood test showed their cancer was getting worse
• 3 of the 77 people (4%) because of a side effect that might be due to taking part in the trial 
• 7 out of 77 people (9%) due to other reasons such as withdrawing their consent and not having treatment for 28 days or more

Conclusion
The study team concluded that giving taselisib and palbociclib together was safe. They also said that the side effects were manageable. This was also the case if they had it with or without hormone therapy.

The say that the combination of taselisib, palbociclib and fulvestrant showed promise. This was for people with breast cancer that had the PIKC3A gene change, was ER positive and HER2 negative.  

And that taselisib with palbociclib might benefit people who have breast cancer that:

• has the PIKC3A gene change
• is not hormone dependent  and
• is HER2 negative 

This evidence shows that the 3 drugs together are useful and the team suggest further research to find out more. 

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.