Drug Interaction Report

MONITOR CLOSELY: Coadministration of cabozantinib and drugs that interfere with platelet function or coagulation may potentiate the risk of bleeding complications. Treatment with cabozantinib is associated with severe, sometimes fatal hemorrhage including hemoptysis and gastrointestinal hemorrhage. In clinical trials, the incidence of Grade 3 hemorrhagic events was higher in patients receiving cabozantinib compared with placebo (3% vs. 1%).

MANAGEMENT: Concomitant use of other medications that interfere with platelet function or coagulation should be considered cautiously in patients treated with cabozantinib. 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.

ADJUST DOSING INTERVAL: Food may alter the oral bioavailability of cabozantinib. When healthy subjects were given a single 140 mg oral dose with a high-fat meal, cabozantinib peak plasma concentration (Cmax) and systemic exposure (AUC) increased by 41% and 57%, respectively, relative to administration under fasting conditions. In clinical studies, patients were administered cabozantinib without food.

GENERALLY AVOID: Coadministration with grapefruit juice is likely to increase the plasma concentrations of cabozantinib, 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: Cabozantinib should be administered at least one hour before or two hours after a meal. The consumption of grapefruit, grapefruit juice, and supplements that contain grapefruit extract should be avoided.