Midostaurin (Specialist drug)

How it works

It inhibits multiple receptor tyrosine kinases, including mutated FLT3 and KIT, blocking downstream signalling that drives proliferation and survival of malignant myeloid and mast cells.

Prescribing in practice

• It can prolong the QT interval and cause serious, sometimes fatal, pulmonary toxicity such as interstitial lung disease, so investigate new respiratory symptoms urgently and review concomitant QT-prolonging drugs.
• Severe nausea and vomiting are common and antiemetic prophylaxis is advised, with administration alongside food to improve tolerability.
• It is extensively metabolised by CYP3A4, so avoid or carefully manage strong CYP3A4 inhibitors and inducers per the SPC.

Monitoring

Monitor full blood count, electrolytes including magnesium and potassium, ECG for QT changes, and respiratory status throughout treatment.

Counselling the patient

• Take capsules with food and use the prescribed anti-sickness medicine.
• Report breathlessness, cough, fever or fainting promptly.
• Avoid grapefruit and tell the team about all other medicines, including over-the-counter products.

Evidence & guidelines

Midostaurin is a NICE-appraised specialist treatment for FLT3-mutated AML and advanced systemic mastocytosis, used within established haemato-oncology protocols.