Drug Interactions between cobicistat / darunavir / emtricitabine / tenofovir alafenamide and revumenib

ADJUST DOSE: Coadministration with potent inhibitors of CYP450 3A4 may significantly increase the plasma concentrations of revumenib, which has been shown to be primarily metabolized by the isoenzyme. In pharmacokinetic studies in patients with relapsed or refractory acute leukemia, revumenib area under the concentration-time curve (AUC) and peak plasma concentration (Cmax) increased 2-fold following concomitant use with the potent CYP450 3A4 inhibitors posaconazole, itraconazole, and voriconazole, and 2.5-fold following concomitant use with the potent CYP450 3A4 inhibitor cobicistat. Increased exposure to revumenib may increase the risk of QT interval prolongation, which has been associated with ventricular arrhythmias including torsade de pointes and sudden death.

MANAGEMENT: If concomitant use of revumenib with potent CYP450 3A4 inhibitors is required, the manufacturer recommends a dose reduction of revumenib. For patients weighing 40 kilograms or more, reduce the dose from 270 mg orally twice daily to 160 mg orally twice daily. For patients weighing less than 40 kilograms, reduce the dose from 160 mg/m2 orally twice daily to 95 mg/m2 orally twice daily based on the patient's body surface area (BSA). Following discontinuation of the potent CYP450 3A4 inhibitor, revumenib dosing may be increased to the recommended dose for patients not receiving a potent CYP450 3A4 inhibitor, after at least 5 half-lives of the inhibitor. Patient tolerability should be assessed throughout treatment, and for those experiencing certain serious adverse effects (e.g., QT prolongation and torsade de pointes arrhythmia, differentiation syndrome, neutropenia, thrombocytopenia), revumenib treatment should be interrupted and/or the dose should be further reduced in accordance with product labeling. Additional adverse effects to closely monitor for include nausea, infection, hypokalemia, hemorrhage, and musculoskeletal pain. It is advised to perform an electrocardiogram (ECG) prior to the initiation of revumenib, at least once a week for the first 4 weeks, and at least monthly thereafter to monitor for QT prolongation. Revumenib should not be started if baseline QTc is greater than 450 msec. Likewise, treatment should be interrupted and the dose adjusted in patients who develop QTc prolongation greater than 480 msec. Patients should be advised to seek prompt medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, lightheadedness, fainting, palpitation, irregular heart rhythm, shortness of breath, or syncope.

MONITOR: Coadministration of tenofovir and darunavir-ritonavir or darunavir-cobicistat may result in increased plasma concentrations of tenofovir and darunavir. Increased tenofovir plasma concentration may increase the risk for tenofovir-related renal adverse effects, including renal impairment, renal failure, elevated creatinine, and Fanconi syndrome. The mechanism of this interaction is unknown; however, increased tenofovir concentrations may be related to inhibition of P-glycoprotein by darunavir, cobicistat, or ritonavir in the renal tubules. Cobicistat may decrease estimated creatinine clearance via inhibition of tubular secretion of creatinine; however, renal glomerular function does not appear to be affected. In 12 study subjects, administration of darunavir-ritonavir (300 mg-100 mg twice daily) with tenofovir (300 mg once daily) increased the systemic exposure (AUC) and trough plasma concentration (Cmin) of darunavir by 21% and 24%, respectively, compared to administration without tenofovir. Tenofovir AUC and Cmin also increased by 22% and 37%, respectively, in the presence of darunavir-ritonavir. Data are lacking to determine whether concomitant use of tenofovir with cobicistat-containing regimens is associated with a greater risk of renal complications compared with regimens that do not include cobicistat.

MANAGEMENT: Caution and close monitoring of renal function is recommended if darunavir-ritonavir or darunavir-cobicistat is to be used in combination with tenofovir, particularly in patients with risk factors for renal impairment. No dose adjustments appear necessary during coadministration of darunavir-ritonavir with tenofovir. However, initiation of cobicistat or cobicistat-containing regimens is not recommended in patients with CrCl less than 70 mL/min if any coadministered medicine requires dose adjustment based on renal function (including tenofovir) or is nephrotoxic.

MONITOR: Concomitant use of tenofovir with cobicistat may increase the risk for tenofovir-related renal adverse effects, including renal impairment, renal failure, elevated creatinine, and Fanconi syndrome. The mechanism of this interaction has not been described. Cobicistat may decrease estimated creatinine clearance via inhibition of tubular secretion of creatinine; however, renal glomerular function does not appear to be affected. When given concomitantly with cobicistat, the systemic exposure (AUC) and trough plasma concentrations (Cmin) of tenofovir was also increased by 23% and 55%, respectively. However, data are lacking to determine whether concomitant use of tenofovir with cobicistat-containing regimens is associated with a greater risk of renal complications compared with regimens that do not include cobicistat.

MANAGEMENT: Initiation of cobicistat or cobicistat-containing regimens is not recommended in patients with CrCl less than 70 mL/min if any coadministered medicine requires dose adjustment based on renal function (including tenofovir), or is nephrotoxic. If concomitant therapy is necessary, monitoring of renal function is recommended, particularly in patients with risk factors for renal impairment.

GENERALLY AVOID: Cobicistat may increase the plasma concentrations of antiretroviral agents. The plasma concentrations of cobicistat may also be increased or reduced in the presence of antiretroviral agents. The proposed mechanism is cobicistat inhibition of the CYP450 3A4 isoenzyme, of which antiretroviral agents may be substrates, and the inhibition or induction of CYP450 3A4 by concomitant antiretroviral medications. Cobicistat is a mechanism-based inhibitor and substrate of CYP450 3A4 with no antiretroviral activity of its own. Rather, it is indicated in its capacity as a pharmacokinetic booster of CYP450 3A4 to increase the systemic exposure of some antiretroviral medications such as atazanavir, darunavir, and elvitegravir, which are substrates of this isoenzyme. Concomitant use of other antiretroviral agents with cobicistat may also increase the plasma levels and risk of side effects associated with these medicines. In contrast, concomitant use of cobicistat-boosted atazanavir or darunavir with CYP450 3A4 inducers nevirapine, etravirine, or efavirenz may reduce the plasma concentrations of cobicistat, darunavir, and atazanavir, leading to a potential loss of therapeutic effect and development of resistance to darunavir and atazanavir. Pharmacokinetic data are not available.

MANAGEMENT: Cobicistat is not intended for use with more than one antiretroviral medication that requires pharmacokinetic enhancement, such as two protease inhibitors or elvitegravir in combination with a protease inhibitor. In addition, cobicistat should not be used concomitantly with ritonavir due to their similar effects on CYP450 3A4. According to some authorities, use of the antiretroviral combinations of atazanavir-cobicistat or darunavir-cobicistat concomitantly with the CYP450 3A4 inducers efavirenz, etravirine, or nevirapine is also not recommended. Other authorities consider the administration of atazanavir-cobicistat with efavirenz or nevirapine to be contraindicated. Since dosing recommendations have only been established for a number of antiretroviral medications, product labeling and current antiretroviral treatment guidelines should be consulted.

Coadministration with mild or moderate inhibitors of CYP450 3A4 may increase the plasma concentrations of revumenib, which has been shown to be primarily metabolized by the isoenzyme. However, clinically significant differences in revumenib pharmacokinetics were not observed when used concomitantly with the moderate CYP450 3A4 inhibitors fluconazole and isavuconazole. Based on these observations, revumenib may be administered with mild or moderate CYP450 3A4 inhibitors without the need for dose adjustments.