Drug Interaction Report

Coadministration with CYP450 3A4 inhibitors is not expected to have clinically significant effects on the plasma concentrations of cabazitaxel, a narrow therapeutic index drug, which is primarily metabolized via the isoenzyme. A drug interaction study in patients with advanced cancers (n=13), revealed repeated administration of the moderate CYP450 3A4 inhibitor aprepitant (125 mg or 80 mg once daily) did not modify the exposure to cabazitaxel (15 mg/m2 intravenous). Clinical data with less potent CYP450 3A4 inhibitors are not available.

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of crizotinib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits. Because crizotinib is associated with concentration-dependent prolongation of the QT interval, increased levels may potentiate the risk of ventricular arrhythmias such as torsade de pointes and sudden death.

Food has no significant effect on the gastrointestinal absorption of crizotinib. According to the product labeling, a high-fat meal reduced crizotinib peak plasma concentration (Cmax) and systemic exposure (AUC) by approximately 14%.

MANAGEMENT: Patients treated with crizotinib should avoid consumption of grapefruit, grapefruit juice, and any supplement containing grapefruit extract. Crizotinib may be taken without regards to food.