Drug Interactions between atazanavir and brigatinib

ADJUST DOSING INTERVAL: Administration of atazanavir with food enhances oral bioavailability and reduces pharmacokinetic variability. According to the manufacturer, administration with a light meal increased the peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of a single 400 mg dose of atazanavir by 57% and 70%, respectively, relative to the fasting state. Administration with a high-fat meal resulted in a mean increase of 35% in atazanavir AUC and no change in Cmax compared to fasting. The coefficient of variation of AUC and Cmax decreased by approximately one-half when given with either a light or high-fat meal compared to the fasting state.

MANAGEMENT: To ensure maximal oral absorption, atazanavir should be administered with or immediately after a meal.

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of brigatinib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. 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. Itraconazole, a potent CYP450 3A4 inhibitor, has been shown to double brigatinib systemic exposure (AUC) in healthy volunteers. Increased exposure to brigatinib may increase the risk of adverse effects such as nausea, vomiting, diarrhea, hypertension, bradycardia, hyperglycemia, visual disturbances, lymphopenia, anemia, and elevations in pancreatic enzymes and creatine phosphokinase.

Food does not significantly affect the oral bioavailability of brigatinib. When brigatinib was administered to healthy volunteers after a high-fat meal (920 calories; 59 g fat, 58 g carbohydrates, 40 g proteins), brigatinib peak plasma concentration (Cmax) decreased by 13% and systemic exposure (AUC) did not change compared to administration after overnight fasting.

MANAGEMENT: Brigatinib may be taken with or without food. Patients should avoid consumption of grapefruit and grapefruit juice during treatment with brigatinib.