Drug Interaction Report

MONITOR: Coadministration of brentuximab vedotin with other agents known to induce hepatotoxicity may potentiate the risk of liver injury. Serious cases of hepatotoxicity, some fatal, have occurred in patients treated with brentuximab vedotin. Cases were consistent with hepatocellular injury, including elevations of transaminases and/or bilirubin, and typically occurred after the first dose or after a rechallenge. Preexisting liver disease and elevated baseline liver enzymes may also increase the risk.

MANAGEMENT: The risk of hepatic injury should be considered when brentuximab vedotin is used with other agents that are potentially hepatotoxic (e.g., acetaminophen; alcohol; androgens and anabolic steroids; antituberculous agents; azole antifungal agents; ACE inhibitors; cyclosporine (high dosages); disulfiram; endothelin receptor antagonists; interferons; ketolide and macrolide antibiotics; kinase inhibitors; minocycline; nonsteroidal anti-inflammatory agents; HIV reverse transcriptase inhibitors; proteasome inhibitors; retinoids; sulfonamides; tamoxifen; thiazolidinediones; tolvaptan; vincristine; zileuton; anticonvulsants such as carbamazepine, hydantoins, felbamate, and valproic acid; lipid-lowering medications such as fenofibrate, lomitapide, mipomersen, niacin, and statins; herbals and nutritional supplements such as black cohosh, chaparral, comfrey, DHEA, kava, pennyroyal oil, and red yeast rice). Patients should be advised to seek medical attention if they experience potential signs and symptoms of hepatotoxicity such as fever, rash, itching, anorexia, nausea, vomiting, fatigue, malaise, right upper quadrant pain, dark urine, pale stools, and jaundice. Liver enzymes and bilirubin should be measured before and during treatment, especially in patients with underlying hepatic disease or marked baseline transaminase elevations. Patients experiencing new, worsening, or recurrent hepatotoxicity may require a delay, change in dosage, or discontinuation of brentuximab vedotin in accordance with the product labeling.

ADJUST DOSING INTERVAL: Food enhances the oral bioavailability of bosutinib. When given with a high-fat meal, bosutinib peak plasma concentration (Cmax) and systemic exposure (AUC) increased by 1.8- and 1.7-fold, respectively.

GENERALLY AVOID: Coadministration with grapefruit juice is likely to increase the plasma concentrations of bosutinib, which is primarily metabolized by CYP450 3A4. However, the interaction has not been studied. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit.

MANAGEMENT: Bosutinib should be administered with a meal. The consumption of grapefruit, grapefruit juice, and supplements that contain grapefruit extract should be avoided.