Drug Interactions between capivasertib and elacestrant

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of elacestrant, 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 elacestrant (172 mg once daily) was administered with itraconazole, a potent CYP450 3A4 inhibitor, elacestrant peak plasma concentration (Cmax) and systemic exposure (AUC) increased by 4.4-fold and 5.3-fold, respectively. Concomitant use of fluconazole, a moderate CYP450 3A4 inhibitor, is predicted to increase elacestrant (345 mg single dose) Cmax and AUC by 1.6-fold and 2.3-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 elacestrant may increase the risk of adverse reactions such as musculoskeletal pain, nausea, dyslipidemia, increased liver enzymes, fatigue, decreased hemoglobin, and vomiting.

Administration of elacestrant (345 mg) with a high-fat meal (800 to 1000 calories, 50% fat) increased elacestrant Cmax and AUC by 42% and 22%, respectively, compared to fasted conditions.

MANAGEMENT: It may be advisable for patients to avoid consumption of grapefruit, grapefruit juice, or supplements that contain grapefruit during treatment with elacestrant. Elacestrant should be taken with food at approximately the same time each day.

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of capivasertib, 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 studied with other CYP450 3A4 inhibitors. Based on clinical studies and model-informed approaches, concomitant use with the potent CYP450 3A4 inhibitor itraconazole is predicted to increase capivasertib systemic exposure (AUC) by up to 1.7-fold and peak plasma concentration (Cmax) by up to 1.4-fold. Coadministration with the moderate CYP450 3A4 inhibitors erythromycin and verapamil is predicted to increase the AUC and Cmax of capivasertib by up to 1.5-fold 1.3-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 capivasertib may increase the risk of adverse effects such as diarrhea, cutaneous adverse reactions, decreased lymphocytes, decreased hemoglobin, hyperglycemia, nausea, and fatigue.

MANAGEMENT: It may be advisable for patients to avoid the consumption of grapefruit, grapefruit juice, or supplements that contain grapefruit during treatment with capivasertib.