Drug Interaction Report

MONITOR: Data from animal studies suggest that coadministration at the same time as brincidofovir may reduce the immune response to the live smallpox vaccine (vaccinia virus). The immune response to live-attenuated, non-replicating smallpox vaccine (modified vaccinia virus Ankara) may also be reduced. Potential interactions between brincidofovir and vaccines have not been studied in humans. The clinical impact of this potential interaction is unknown.

MANAGEMENT: The potential for reduced immune response to the live smallpox vaccine and live-attenuated, non-replicating smallpox vaccine should be monitored if coadministered with brincidofovir.

ADJUST DOSING INTERVAL: Administration with food decreases the oral bioavailability of brincidofovir. According to the product labeling, administration of brincidofovir tablets with a low-fat meal (approximately 400 calories, 25% of calories from fat) was associated with a reduction in the systemic exposure (AUC) and peak plasma concentration (Cmax) of brincidofovir by 31% and 49%, respectively, compared to administration under fasting. However, no clinically meaningful changes in intracellular concentrations of cidofovir diphosphate were observed. The effect of food on the oral suspension formulation has not been evaluated.

MANAGEMENT: Brincidofovir oral tablets and suspension should be taken on an empty stomach. If necessary, the oral tablets may be taken with a low-fat meal.