A trial comparing bosutinib with imatinib as treatment for chronic myeloid leukaemia

Cancer type:

Blood cancers

Chronic leukaemia

Chronic myeloid leukaemia (CML)

Leukaemia

Status:

Results

Phase:

Phase 3

This trial compared bosutinib with imatinib to treat newly diagnosed chronic myeloid leukaemia (CML).

More about this trial

There are different phases of chronic myeloid leukaemia (CML). They are:

chronic phase
accelerated phase
blast phase

This trial was for people with CML in the chronic phase. This is when the leukaemia is still developing slowly.

Doctors can treat chronic phase CML with a drug called imatinib (Glivec). This works well, but researchers wanted to see if bosutinib (Bosulif) would work better and not cause too many side effects.

Bosutinib is a type of cancer growth blocker. It stops signals that cancer cells use to grow and divide.

The aims of this trial were to find out:

if bosutinib works better than imatinib
how well bosutinib works for chronic phase CML
more about the side effects

Summary of results

This trial showed that bosutinib worked better than imatinib and didn’t cause too many side effects.

The research team recruited patients in 2014 and 2015, and published the results in 2017.

Results

This trial recruited 536 people with newly diagnosed chronic myeloid leukaemia (CML). They all had CML that was in the chronic phase. They were put in to 1 of 2 treatments groups at random, and:

half had bosutinib tablets once a day
half had imatinib tablets once a day

The trial team looked at how well the drugs worked a year after starting treatment. They measured this in two ways.

The first way they measured how well treatment worked was to look for the number of leukaemia cells in blood samples. It’s called major molecular response (MMR) when there are only a very tiny number of these cells in the blood.

The number of people who had a major molecular response was:

nearly 5 out of 10 people (47%) who had bosutinib
nearly 4 out of 10 people (37%) who had imatinib

The second way they measured how well treatment worked was to look for cells in the bone marrow that have a specific genetic change. It’s called complete cytogenetic response (CCyR) when there are none of these cells in the bone marrow.

The number of people who had a complete cytogenetic response was:

nearly 8 out of 10 people (77%) who had bosutinib
nearly 7 out of 10 people (66%) who had imatinib

They also found that people who had bosutinib responded to treatment quicker than those who had imatinib.

When they looked at how many people’s leukaemia had progressed to either the accelerated phase or the blast phase, it was:

4 people (1.6%) who’d had bosutinib
6 people (2.5%) who’d had imatinib

Side effects

Nearly everyone taking part had at least 1 side effect. But some were mild or went away with time. The number of people who had more severe side effects was:

nearly 6 out of 10 people (56%) who had bosutinib
more than 4 out of 10 people (43%) who had imatinib

The most common side effects of bosutinib were:

diarrhoea
feeling sick
a drop in blood clotting cells (platelets)
a change in liver function tests

The most common side effects of imatinib were:

feeling sick
diarrhoea
muscle spasms
a drop in a specific type of white blood cell (neutrophils)

Conclusion

The research team concluded that bosutinib worked better than imatinib for people with newly diagnosed chronic phase chronic myeloid leukaemia. And that it didn’t cause too many serious side effects. They suggest it could be a useful treatment option for people in this situation.

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.