A study looking at pertuzumab for HER2 positive breast cancer that has spread (PERUSE)

The trial team found that the combination of pertuzumab, trastuzumab and a taxane helped people with HER2 positive breast cancer that had spread. 

About this trial
This was an international phase 3 trial. Of the 1,436 people who were in the trial 1,429 had pertuzumab, trastuzumab and a taxane. During treatment some people swopped from one taxane to another. 

• 775 people initially had docetaxel.
• 589 people initially had paclitaxel.
• 65 people initially had nab paclitaxel.

On average everyone had 24 cycles of treatment  of pembrolizumab and 6 cycles of treatment of taxane.

Results
To find out how well treatment worked the team were able to look at 1,199 people. They had an area of caner the team could measure at the start. Overall treatment helped 959 people. For:

• 175 people there was no sign of their cancer (a complete response)
• 784 people their cancer had shrunk (a partial response)
• 180 people their cancer had stayed the same (stable disease)

Diagram 1

Of the remaining 60 people, for:

• 50 people their cancer had got worse (progressive disease)
• 10 people the team couldn’t measure how well the treatment worked

The team also looked at the median length of time people were without a sign of cancer. They found that overall was just over 20½ months (20.7). When they looked at the 3 taxanes separately the median length of time was:

• just under 19½ months (19.4) for docetaxel
• just over 23 months (23.2) for paclitaxel
• just over 19 months (19.2) for nab paclitaxel

Diagram 2

The team looked at the median length of time people lived after their treatment. They found there wasn’t much difference between the 3 taxanes. The median length of time was just under 5½ years (65 months). 

Side effects
Overall the most common side effects reported were:

• diarrhoea
• hair loss
• feeling or being sick
• tiredness (fatigue)
• feeling weak
• a skin rash
• stiff joints

There were differences in the side effects reported for each taxane. 

• Nerve damage (peripheral neuropathy) and nose bleeds were more common with both paclitaxel and nab paclitaxel than docetaxel.
• A high temperature with a low white blood cell count (febrile neutropenia) and a sore, inflamed mouth was more common with docetaxel than with paclitaxel or nab-paclitaxel.

The reported number and type of very bad side effects was similar for all 3 taxanes. 

This is apart from febrile neutropenia and a general drop in white blood cells. These were the highest in people who had docetaxel. And were the lowest in people who had nab paclitaxel. 

The side effects that caused people to stop pertuzumab and trastuzumab were heart-related problems. This was most commonly a change in the measurements of how well the heart works.

The side effects that caused people to stop their taxane were:

• nerve damage causing pins and needles, tingling and pain
• tiredness 
• diarrhoea

Conclusion
The team concluded that using other taxanes such as paclitaxel or nab paclitaxel instead of docetaxel was just as safe and helpful.  

This may give doctors more choices of treatments that are better tolerated for people with HER2 positive advanced breast cancer.

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.