Drug Interaction Report

MONITOR: Coadministration with blinatumomab may increase the plasma concentrations of drugs that are substrates of CYP450 isoenzymes. Initiation of blinatumomab treatment causes transient release of cytokines that may suppress CYP450 enzymes, although the potential for interaction has not been studied. Presumably, the highest drug-drug interaction risk would be during the first 9 days of the first cycle and the first 2 days of the second cycle.

MANAGEMENT: Caution is advised when blinatumomab is prescribed to patients receiving drugs that are metabolized by CYP450 isoenzymes, particularly those with a narrow therapeutic index such as carbamazepine, colchicine, cyclosporine, disopyramide, phenytoin, quinidine, theophylline, warfarin, macrolide immunosuppressants, vinca alkaloids, and some narcotic analgesics. Clinical and laboratory monitoring are recommended following the initiation of blinatumomab, and the individual dosage of the concomitant agents adjusted as needed.

GENERALLY AVOID: Grapefruit juice may significantly increase the plasma concentrations of orally administered everolimus. The mechanism is inhibition of CYP450 3A4 and P-glycoprotein activity in the gut wall by certain compounds present in grapefruit.

MANAGEMENT: Patients treated with everolimus should avoid consumption of grapefruit and grapefruit juice.