Drug Interaction Report

GENERALLY AVOID: Coadministration of sacituzumab govitecan with inhibitors of uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) may increase the risk of adverse effects, such as nausea, vomiting, diarrhea, and neutropenia. The proposed mechanism involves increased exposure to the pharmacologically active metabolite SN-38, a topoisomerase I inhibitor linked to sacituzumab govitecan, which is metabolized via UGT1A1. Genetic variants of the UGT1A1 gene such as the UGT1A1*28 allele lead to reduced UGT1A1 enzyme activity and patients who are homozygous for the UGT1A1*28 allele are at increased risk for neutropenia from SN-38.

MANAGEMENT: Concomitant use of sacituzumab govitecan with UGT1A1 inhibitors should be avoided. If coadministration is unavoidable, patients should be closely monitored for the development of severe nausea, vomiting, diarrhea, and neutropenia. Patients should be advised to promptly report symptoms such as chills, fever, malaise, sore throat, mouth sores, unusual fatigue, bruising, or bleeding.

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of nilotinib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits. Because nilotinib 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.

ADJUST DOSING INTERVAL: Food increases the oral bioavailability of nilotinib. The mechanism of interaction is unknown. Compared to the fast state, nilotinib systemic exposure (AUC) increased by 82% when the dose was given 30 minutes after a high-fat meal. Because nilotinib 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.

MANAGEMENT: Patients treated with nilotinib should avoid consumption of grapefruit, grapefruit juice, and any supplement containing grapefruit extract. In addition, no food should be consumed for at least 2 hours before and 1 hour after a nilotinib dose.