Gilteritinib has been associated with prolonged QT interval, increasing the risk of cardiac arrhythmia. Patients with QTc > 500 msec should not be commenced on gilteritinib, and treatment should be interrupted.
QT prolongation can be observed in the first 3 months of treatment. Therefore, an electrocardiogram (ECG) should be performed prior to commencement of treatment and on day 8 and 15 of cycle 1, and prior to the start of the next 3 subsequent months of treatment. In addition, an ECG should be performed in case of dose increase, following the same schedule.
Hypokalaemia or hypomagnesaemia may increase the QT prolongation risk. Risk factors (e.g. electrolyte abnormalities) should be corrected, where possible, prior to commencement of gilteritinib and the concurrent use of drugs that may prolong the QT interval should be avoided. Note that azole antifungals may contribute to QTc prolongation.
If QT prolongation occurs, treatment interruption, dose modification or treatment discontinuation may be required. Consider review by a cardiologist.