Drug Interaction Report

MONITOR: Lazertinib may increase the concentration and adverse effects of drugs which rely on CYP450 3A4 and/or breast cancer resistance protein (BCRP) for clearance via inhibition of the isoenzyme and/or the efflux transporter. However, for drugs whose therapeutic effects are dependent on the formation of active metabolites via CYP450 3A4 (e.g., amiodarone, cyclophosphamide, ifosfamide), inhibition of this isoenzyme may result in a reduction in efficacy. In one pharmacokinetic study, healthy participants (n=20) received the sensitive CYP450 3A4 substrate midazolam and BCRP substrate rosuvastatin at baseline and again with steady-state lazertinib. Coadministration increased midazolam's peak plasma concentration (Cmax) and systemic exposure (AUC) by 1.4- and 1.5-fold, respectively. Likewise, rosuvastatin's Cmax and AUC increased by 2.2- and 2-fold, respectively. Data for less sensitive substrates or drugs metabolized and/or transported by multiple routes are unavailable.

MANAGEMENT: Caution is advised if lazertinib is used concurrently with agents that are substrates of CYP450 3A4 and/or the efflux transporter BCRP. This may be particularly important in cases where minimal changes in the substrate's concentration could result in serious adverse reactions (if the agent is cleared via CYP450 3A4 and/or BCRP) or a significant reduction in efficacy (if the medication has active metabolites formed via CYP450 3A4). Dose adjustments and/or increased monitoring may be required. Consultation with the labeling of the substrate in question is advised.

GENERALLY AVOID: Coadministration with grapefruit juice may increase the plasma concentrations of macitentan, which is primarily metabolized by CYP450 3A4. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. The interaction has not been studied with grapefruit juice but has been reported for ketoconazole, a potent CYP450 3A4 inhibitor. In ten healthy subjects, coadministration of a single 10 mg oral dose of macitentan on day 5 of treatment with ketoconazole (400 mg daily for 24 days) resulted in an approximately 2-fold increase in macitentan systemic exposure compared to administration alone. However, the clinical significance of the interaction is unclear. 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. Pharmacokinetic interactions involving grapefruit juice are also subject to a high degree of interpatient variability, thus the extent to which a given patient may be affected is difficult to predict.

MANAGEMENT: Until further information is available, patients receiving macitentan therapy should avoid the consumption of grapefruit or grapefruit juice.