Drug Interaction Report

MONITOR: The concomitant or sequential administration of multiple antineoplastic agents may result in additive toxicities, particularly in the bone marrow, gastrointestinal tract and heart.

MANAGEMENT: Close clinical and laboratory monitoring for hematologic and nonhematologic toxicities are recommended when antineoplastic agents are administered concurrently or during close intervals. Dosing adjustments may be necessary. The manufacturers' recommendations and institutional protocols for dosage, treatment regimens, monitoring, and management of toxicities should be consulted.

GENERALLY AVOID: Coadministration with grapefruit juice may increase the plasma concentrations of trabectedin. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit.

GENERALLY AVOID: Coadministration of trabectedin with other agents known to induce hepatotoxicity such as alcohol may potentiate the risk of liver injury. Reversible, acute increases in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) have occurred frequently in patients treated with trabectedin alone or with pegylated liposomal doxorubicin in clinical trials. In one U.S. trial with 378 patients, grade 3 or 4 elevated liver function tests (defined as elevations in ALT, AST, total bilirubin, or alkaline phosphatase) were reported in 35% of patients receiving trabectedin. ALT or AST elevations greater than eight times the upper limit of normal (ULN) occurred in 18% of patients, and drug-induced liver injury (defined as concurrent elevations in ALT or AST more than three times ULN, alkaline phosphatase less than two times ULN, and total bilirubin at least two times ULN) occurred in 1.3% of patients.

MANAGEMENT: Consumption of grapefruit or grapefruit juice during treatment with trabectedin should be avoided. Excessive use of alcohol is also not recommended. Patients should be advised to seek medical attention if they experience potential signs and symptoms of hepatotoxicity such as fever, rash, itching, anorexia, nausea, vomiting, fatigue, malaise, right upper quadrant pain, dark urine, pale stools, and jaundice. Monitoring of alkaline phosphatase, bilirubin, AST, and ALT should occur regularly during trabectedin treatment in accordance with the product labeling, or as often as necessary when clinical symptoms develop. Trabectedin must not be used in patients with elevated bilirubin at the time of initiation of cycle. Elevated liver function tests should be managed with treatment interruption, dosage reduction, or permanent discontinuation depending on the severity and duration of abnormality.