Drug Interactions between encorafenib and lemborexant

GENERALLY AVOID: Coadministration with potent or moderate inhibitors of CYP450 3A4 may significantly increase the plasma concentrations of encorafenib, which is primarily metabolized by the isoenzyme. When a single 50 mg dose of encorafenib (equivalent to 0.1 times the recommended dose) was administered with posaconazole, a potent CYP450 3A4 inhibitor, encorafenib peak plasma concentration (Cmax) increased by 68% and systemic exposure (AUC) increased by 3-fold. When the same dose of encorafenib was administered with diltiazem, a moderate CYP450 3A4 inhibitor, encorafenib Cmax increased by 45% and AUC increased by 2-fold. Increased exposure to encorafenib may increase the risk of serious and life-threatening adverse effects such as hemorrhage, uveitis, QT prolongation, hepatotoxicity, dermatologic reactions, and new malignancies.

MANAGEMENT: Concomitant use of encorafenib with grapefruit or grapefruit juice should generally be avoided. If coadministration is required, the manufacturer recommends reducing the encorafenib dose to one-third of the dose used prior to addition of a potent CYP450 3A4 inhibitor or one-half of the dose used prior to addition of a moderate CYP450 3A4 inhibitor. After the inhibitor has been discontinued for 3 to 5 elimination half-lives, the encorafenib dose that was taken prior to initiating the inhibitor may be resumed.

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of lemborexant, which is primarily metabolized by CYP450 3A4. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Inhibition of hepatic CYP450 3A4 may also contribute. The interaction has not been studied with grapefruit juice but has been reported for other CYP450 3A4 inhibitors. When coadministered with itraconazole, a potent CYP450 3A4 inhibitor, lemborexant peak plasma concentration (Cmax) and systemic exposure (AUC) increased approximately 1.4-fold and 3.8-fold, respectively. When coadministered with fluconazole, a moderate CYP450 3A4 inhibitor, lemborexant Cmax and AUC increased approximately 1.6-fold and 4.2-fold, respectively. In general, the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition. Increased exposure to lemborexant may increase the risk of adverse reactions such as central nervous system (CNS) depression, sleep paralysis, hallucinations, complex sleep behaviors, worsening of depression or suicidal ideation, nightmares, palpitations, or headache.

After administration of a high-fat, high-calorie meal (approximately 1000 calories with 500 to 600 calories from fat), lemborexant Cmax decreased by 23%, AUC increased by 18%, and the time to maximum concentration (Tmax) was delayed by 2 hours.

MANAGEMENT: The manufacturer makes no recommendation regarding administration with food; however, the time to sleep onset may be delayed if taken with or soon after a meal. Patients should avoid consumption of grapefruit, grapefruit juice, or supplements that contain grapefruit during treatment with lemborexant.