Drug Interactions between Brukinsa and Truseltiq

GENERALLY AVOID: Grapefruit and/or grapefruit juice may increase the plasma concentrations of zanubrutinib. 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 zanubrutinib was coadministered with the potent CYP450 3A4 inhibitor itraconazole (200 mg once daily), zanubrutinib peak plasma concentration (Cmax) and systemic exposure (AUC) increased 157% and 278%, respectively, in healthy volunteers. Data evaluating coadministration of zanubrutinib, in patients with B-cell lymphoma, and several other known CYP450 3A4 inhibitors have been reported. When zanubrutinib was coadministered with another CYP450 3A4 inhibitor, clarithromycin (250 mg twice daily), zanubrutinib Cmax and AUC increased 101% and 92%, respectively. The moderate CYP450 3A4 inhibitor diltiazem (180 mg once daily) increased both zanubrutinib Cmax and AUC increased by 62%. Another moderate CYP450 3A4 inhibitor, fluconazole (400 mg once daily), increased zanubrutinib Cmax and AUC 81% and 88%, respectively. Clinical data for less potent inhibitors are not available. In general, the effects of grapefruit products are concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit (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 zanubrutinib exposure may potentiate the risk of toxicities such as hemorrhage, infection, cytopenias, malignancies, and serious cardiac arrhythmias, primarily atrial fibrillation and atrial flutter.

Food does not affect the oral bioavailability of zanubrutinib. No clinically significant differences in zanubrutinib Cmax or AUC were observed following administration of a high-fat meal (approximately 1000 calories; 50% from fat) in healthy subjects.

MANAGEMENT: Zanubrutinib may be administered with or without food. Patients should avoid consumption of grapefruit, grapefruit juice, Seville oranges (a citrus relative of the grapefruit), and Seville orange juice during treatment with zanubrutinib. Close clinical monitoring for development of zanubrutinib-related toxicities, dosage adjustments, and/or withholding treatment in accordance with product labeling is advised. Additional consultation with individual package labeling, as well as relevant institutional protocols, may be advisable for further guidance.

ADJUST DOSING INTERVAL: Food may increase the oral bioavailability of infigratinib. Coadministration with a high-fat, high-calorie meal (800 to 1,000 calories, with approximately 50% of total calories from fat) in healthy subjects increased mean infigratinib peak plasma concentration (Cmax) and total systemic exposure (AUC) by 60% to 80% and 80% to 120%, respectively, and increased the median time to Cmax from 4 hours to 6 hours. When coadministered with a low-fat, low-calorie meal (approximately 330 calories, with 20% of total calories from fat), mean infigratinib Cmax and AUC increased by 90% and 70%, respectively, while the median time to Cmax did not change.

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of infigratinib and one of its active metabolites, BHS697, both of which are primarily metabolized by CYP450 3A4 in vitro. 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. Coadministration of infigratinib with multiple doses of itraconazole, a potent CYP450 3A4 inhibitor, increased infigratinib peak plasma concentration (Cmax) and total systemic exposure (AUC) by 164% and 622%, respectively, and the AUC for the active metabolite, BHS697, by 174%. 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 infigratinib and BHS697 may increase the incidence and severity of serious adverse reactions such as infections, anemia, pyrexia, abdominal pain, hypercalcemia, hyperphosphatemia, ocular toxicity (e.g., retinal pigment epithelial detachment), sepsis, stomatitis, diarrhea, palmar-plantar erythrodysesthesia syndrome, increased blood creatinine, increased lipase, and onycholysis.

MANAGEMENT: Infigratinib should be administered on an empty stomach at least one hour before or two hours after food. Patients should avoid consumption of grapefruit, grapefruit juice, or supplements that contain grapefruit during treatment with infigratinib.