Drug Interaction Report

MONITOR CLOSELY: Coadministration of ponatinib and drugs that interfere with platelet function or coagulation may potentiate the risk of bleeding complications. Treatment with ponatinib is associated with severe, sometimes fatal hemorrhage including cerebral and gastrointestinal hemorrhage. In clinical trials, hemorrhagic events occurred in 24% of patients treated with ponatinib, and serious events occurred in 5% of patients. The incidence of serious bleeding events was higher in patients with accelerated phase or blast phase chronic myeloid leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL). Most hemorrhagic events occurred in patients with grade 4 thrombocytopenia.

MANAGEMENT: Concomitant use of other medications that interfere with platelet function or coagulation should be considered cautiously in patients treated with ponatinib. Close clinical and laboratory observation for bleeding complications is recommended during therapy. The INR should be monitored more frequently during coadministration of warfarin. Patients should be advised to promptly report any signs of bleeding to their physician, including pain, swelling, headache, dizziness, weakness, prolonged bleeding from cuts, increased menstrual flow, vaginal bleeding, nosebleeds, bleeding of gums from brushing, unusual bleeding or bruising, red or brown urine, or red or black stools.

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.

ADJUST DOSING INTERVAL: Food reduces the oral bioavailability of betrixaban. When administered with a low-fat (900 calories; 20% fat) or high-fat (900 calories; 60% fat) meal, betrixaban peak plasma concentration (Cmax) and systemic exposure (AUC) decreased relative to administration in the fasting state by an average of 70% and 61%, respectively, with the low-fat meal and 50% and 48%, respectively, with the high-fat meal. The effect of food on betrixaban pharmacokinetics could be observed for up to 6 hours after meal intake.

MANAGEMENT: The manufacturer recommends taking betrixaban at the same time each day with food.