Drug Interaction Report

Consumer information for this interaction is not currently available.

MONITOR: Coadministration with inhibitors of CYP450 3A4 may increase the plasma concentrations of unconjugated monomethyl auristatin E (MMAE), the anti-mitotic and cytotoxic component of telisotuzumab vedotin. Telisotuzumab vedotin is an antibody-drug conjugate (ADC) that releases MMAE via proteolytic cleavage, and MMAE has been shown in vitro to be primarily metabolized by CYP450 3A4. MMAE systemic exposure (AUC) is predicted to increase by 1.4-fold following concomitant administration of telisotuzumab vedotin with the potent CYP450 3A4 inhibitor ketoconazole. It is not known if, and to what extent, MMAE may interact with less potent CYP450 3A4 inhibitors.

MANAGEMENT: Caution is advised when telisotuzumab vedotin is used concomitantly with CYP450 3A4 inhibitors. Patients should be closely monitored for development or exacerbation of toxicities such as ocular surface disorders (e.g., dry eyes, keratitis, blurred vision), peripheral neuropathy, interstitial lung disease/pneumonitis, and peripheral edema. If serious adverse reactions occur, the dosing of telisotuzumab vedotin should be adjusted or withheld as necessary in accordance with the product labeling.

Take lapatinib on an empty stomach 1 hour before or 1 hour after a meal unless otherwise directed by your doctor. This will make it easier for your body to absorb the medication. The lapatinib dose is administered once daily and should not be divided. The usual dose of lapatinib is equal to 5 tablets. You may swallow each tablet one at a time, but take the entire lapatinib dose at the same time each day. If you are receiving therapy with lapatinib you should be advised to avoid grapefruits and grapefruit juice. Grapefruit can raise the levels of lapatinib in your body and lead to dangerous side effects.