Drug Interaction Report

MONITOR CLOSELY: Coadministration of capmatinib with strong CYP450 3A4 inhibitors may increase the risk and severity of capmatinib adverse effects, such as interstitial lung disease, pneumonitis, and hepatotoxicity. The proposed mechanism is decreased clearance due to inhibition of CYP450 3A4, which is one of the primary enzymes responsible for the metabolic clearance of capmatinib. Coadministration with itraconazole (a strong CYP450 3A4 inhibitor) increased the systemic exposure (AUC) of capmatinib by 42%, but did not affect the peak plasma concentration (Cmax) of capmatinib.

MANAGEMENT: Close monitoring is recommended whenever capmatinib is used with a strong CYP450 3A4 inhibitor. Clinical and laboratory monitoring should be considered whenever a strong CYP450 3A4 inhibitor is added to or withdrawn from therapy with capmatinib, and the dosage adjusted as necessary based on clinical response and toxicity. Patients should be monitored for the development of adverse effects.

ADJUST DOSING INTERVAL: Food may reduce the systemic bioavailability of amprenavir from fosamprenavir oral suspension. The mechanism of interaction has not been described. According to the product labeling, administration of fosamprenavir oral suspension (1400 mg single dose) with a high-fat meal (967 kcal, 67 g fat, 33 g protein, 58 g carbohydrate) reduced amprenavir peak plasma concentration (Cmax) by 46% and systemic exposure (AUC) by 28% compared to administration in a fasted state. The time to reach peak plasma level (Tmax) was delayed by 0.72 hours. In contrast, the same high-fat meal did not affect the pharmacokinetics of amprenavir from fosamprenavir tablets.

MANAGEMENT: Fosamprenavir suspension should be administered on an empty stomach in adults, but with food in pediatric patients to aid palatability and compliance. If emesis occurs within 30 minutes after dosing the suspension, the dose should be repeated. Fosamprenavir tablets may be taken with or without food.