Drug Interaction Report

MONITOR: Coadministration with glasdegib may increase the plasma concentrations of drugs that are substrates of the P-glycoprotein (P-gp) and/or breast cancer resistance protein (BCRP) efflux transporters. In vitro data suggest that glasdegib may have the potential to inhibit P-gp (in the gastrointestinal (GI) tract) and BCRP (systemically and in the GI tract) at clinically relevant concentrations, which may result in decreased clearance of concomitantly administered P-gp and BCRP substrates. The clinical relevance is unknown.

MANAGEMENT: Caution is advised if glasdegib is coadministered with drugs that are substrates of P-gp and/or BCRP, particularly those with a narrow therapeutic range. Clinical and laboratory monitoring should be considered whenever glasdegib is added to or withdrawn from therapy with these drugs, and dosages adjusted as necessary. Patients should be monitored for the development of adverse effects.

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.

GENERALLY AVOID: Coadministration with grapefruit or grapefruit juice may increase the plasma concentrations of glasdegib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall induced by certain compounds present in grapefruit. When glasdegib was coadministered with ketoconazole, a potent CYP450 3A4 inhibitor, glasdegib peak plasma concentration (Cmax) and systemic exposure (AUC) increased by 1.4- and 2.4-fold, respectively, compared to administration of glasdegib alone. The interaction has not been studied with other, less potent CYP450 3A4 inhibitors. Because grapefruit juice inhibits primarily intestinal rather than hepatic CYP450 3A4, the magnitude of interaction is greatest for those drugs that undergo significant presystemic metabolism by CYP450 3A4 (i.e., drugs with low oral bioavailability). 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. Pharmacokinetic interactions involving grapefruit juice are also subject to a high degree of interpatient variability, thus the extent to which a given patient may be affected is difficult to predict.

When administered with a high-fat, high-calorie meal (800 to 1000 total calories, 500 to 600 fat calories, 250 carbohydrate calories, and 150 protein calories), glasdegib Cmax and AUC decreased by 31% and 16%, respectively.

MANAGEMENT: Glasdegib may be administered with or without food. Coadministration of grapefruit or grapefruit juice with glasdegib should preferably be avoided.