Drug Interaction Report

GENERALLY AVOID: Coadministration with potent CYP450 3A4 inducers may significantly decrease the plasma concentrations 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.

MANAGEMENT: Given the risk of reduced or loss of clinical response, the manufacturer advises that the concomitant use of ritlecitinib with potent CYP450 3A4 inducers should generally be avoided. Alternative therapeutic agents with less enzyme induction potential should be considered.