Drug Interaction Report

MONITOR: Coadministration with inhibitors of CYP450 3A4 may increase the plasma concentrations of ponatinib, which is a substrate of the isoenzyme. In 22 healthy volunteers, administration of a single 15 mg oral dose of ponatinib in combination with the potent CYP450 3A4 inhibitor ketoconazole (400 mg daily) increased ponatinib peak plasma concentration (Cmax) and systemic exposure (AUC) by 47% and 78%, respectively, compared to administration of ponatinib alone. No data are available for use with less potent CYP450 3A4 inhibitors.

MANAGEMENT: Caution is advised if ponatinib is used in combination with moderate CYP450 3A4 inhibitors. Patients should be monitored for potentially increased side effects such as thromboembolism, ischemia, congestive heart failure, hypertension, hepatotoxicity, pancreatitis, myelosuppression, hemorrhage, and fluid retention.

GENERALLY AVOID: Coadministration with grapefruit juice is likely to increase the plasma concentrations of ponatinib, which is primarily metabolized by CYP450 3A4. However, the interaction has not been studied. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit.

MANAGEMENT: The consumption of grapefruit, grapefruit juice, and supplements that contain grapefruit extract should be avoided during treatment with ponatinib.