Bosutinib

How it works

It inhibits the BCR-ABL fusion kinase, and also Src-family kinases, blocking the aberrant signalling that drives proliferation of the leukaemic clone.

Prescribing in practice

• Diarrhoea is very common and can be severe early in treatment, and hepatotoxicity with marked transaminase rises may occur, requiring monitoring and dose interruption.
• It is a specialist haematology agent; fluid retention, myelosuppression and QT prolongation also warrant attention.
• Exposure is increased by strong CYP3A inhibitors and reduced by inducers, and absorption is affected by gastric acid, so review interacting medicines.

Monitoring

Monitor liver function and full blood count regularly, particularly in the early months, along with fluid status and haematological response.

Counselling the patient

• Report severe or persistent diarrhoea, abdominal pain, or yellowing of the skin or eyes.
• Take the tablets with food and avoid grapefruit and St John's wort.
• Effective contraception is advised during treatment.

Evidence & guidelines

Its efficacy in chronic myeloid leukaemia is established in the BFORE and earlier registration trials and reflected in its licensed use.