Drug Interaction Report

MONITOR: Coadministration with CYP450 3A4 inducers may decrease the plasma concentration and pharmacologic effects of ritlecitinib. The proposed mechanism is increased clearance of ritlecitinib due to induction of the CYP450 3A4 isoenzyme, one of the pathways of elimination of ritlecitinib. When a single 50 mg dose of ritlecitinib was administered in combination with the potent CYP450 3A4 inducer rifampin (600 mg once daily for 8 days), the mean peak plasma concentration (Cmax) and systemic exposure (AUC) of ritlecitinib decreased by approximately 25% and 44%, respectively, compared to ritlecitinib administered alone. Data are not available of other, less potent inducers.

MANAGEMENT: Caution is advised when ritlecitinib is used with CYP450 3A4 inducers. The possibility of diminished therapeutic effects should be considered.

ADJUST DOSING INTERVAL: Food may increase the extent of tecovirimat absorption following oral administration. When the recommended oral dose of tecovirimat (600 mg every 12 hours) was administered with a meal (approximately 600 calories and 25 g of fat) in healthy adults weighing less than 120 kg, tecovirimat absorption increased by 39% relative to fasting.

MANAGEMENT: Oral tecovirimat should be taken within 30 minutes after a full meal containing moderate or high fat (approximately 600 calories and 25 g of fat) with 6 to 8 ounces of water.