Istodax (romidepsin) lyophilized powder
Detailed View: Safety Labeling Changes Approved By FDA Center for Drug Evaluation and Research (CDER) – June 2013
Drugs that Inhibit Cytochrome P450 3A4 Enzymes
- Romidepsin is metabolized by CYP3A4. Strong CYP3A4 inhibitors increase concentrations of romidepsin. In a pharmacokinetic drug interaction trial the strong CYP3A4 inhibitor ketoconazole increased romidepsin (AUC0-∞) by approximately 25%.
- Monitor for toxicity related to increased romidepsin exposure and follow the dose modifications for toxicity when romidepsin is initially co-administered with strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, clarithromycin, atazanavir, indinavir, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, voriconazole).
Drugs that Induce Cytochrome P450 3A4 Enzymes
- Avoid co-administration of ISTODAX with rifampin.
- In a pharmacokinetic drug interaction trial with co-administered rifampin (a strong CYP3A4 inducer), romidepsin exposure was increased by approximately 80% and 60% for AUC0-∞ and Cmax, respectively. Typically, co-administration of CYP3A4 inducers decrease concentrations of drugs metabolized by CYP3A4. The increase in exposure seen after co-administration with rifampin is likely due to rifampin’s inhibition of an undetermined hepatic uptake process that is predominantly responsible for the disposition of Istodax.
- It is unknown if other potent CYP3A4 inducers (e.g., dexamethasone, carbamazepine, phenytoin, rifabutin, rifapentine, phenobarbital, St. John’s Wort) would alter the exposure of Istodax. Therefore, the use of other potent CYP3A4 inducers should be avoided when possible.