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

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.

MONITOR: Coadministration with berotralstat may increase the plasma concentrations and effects of drugs that are substrates of the efflux transporter P-glycoprotein (P-gp). The mechanism is decreased clearance due to inhibition of P-gp activity by berotralstat. The administration of a 300 mg dose of berotralstat (twice the recommended daily dose) increased the peak plasma concentration (Cmax) and systemic exposure (AUC) of the sensitive P-gp substrate digoxin, by approximately 1.6-fold and 1.5-fold, respectively. Clinical data are not available.

MANAGEMENT: Caution is advised when berotralstat is coadministered with drugs that are substrates of P-gp, particularly those with a narrow therapeutic index. This interaction has only been reported at twice the recommended daily dose of berotralstat. Clinical and laboratory monitoring should be considered following the initiation or discontinuation of berotralstat, and the individual dosage of the concomitant agents adjusted as needed.

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.

MONITOR: Coadministration with berotralstat may increase the plasma concentrations and effects of drugs that are substrates of CYP450 3A4 and/or 2D6. The mechanism is decreased clearance due to inhibition of CYP450 3A4 and 2D6 activity by berotralstat. Berotralstat is considered a moderate inhibitor of CYP450 3A4 and 2D6. In drug interaction studies, berotralstat reportedly increased the peak plasma concentration (Cmax) and systemic exposure (AUC) of the sensitive CYP450 3A4 substrate midazolam by approximately 1.5-fold and 2.25-fold, respectively, and the CYP450 3A4 substrate amlodipine by approximately 1.5-fold and 1.75-fold, respectively. It increased the Cmax and AUC of the sensitive CYP450 2D6 substrate dextromethorphan by approximately 2.9-fold and 2.7-fold, respectively, and the CYP450 2D6 substrate desipramine by 1.7-fold and 1.9-fold, respectively. Clinical data are not available.

MANAGEMENT: Caution is advised when berotralstat is coadministered with drugs that are substrates of CYP450 3A4 and/or 2D6, particularly those with a narrow therapeutic index. Clinical and laboratory monitoring are recommended following the initiation of berotralstat, and the individual dosages of the concomitant agents adjusted as needed.

MONITOR: Coadministration of berotralstat with drugs that are both substrates of the isoenzyme CYP450 3A4 as well as inhibitors of the efflux transporters P-glycoprotein (P-gp) and/or breast cancer resistance protein (BCRP) may lead to an increase in the plasma concentrations and effects of both drugs. Berotralstat is considered a moderate CYP450 3A4 inhibitor and has been reported in drug interaction studies to increase the peak plasma concentration (Cmax) and systemic exposure (AUC) of the sensitive CYP450 3A4 substrate midazolam by approximately 1.5-fold and 2.25-fold, respectively. In addition, berotralstat is a substrate of both P-gp and BCRP. Coadministration with the potent P-gp and BCRP inhibitor cyclosporine increased berotralstat peak plasma concentration (Cmax) and total systemic drug exposure (AUC 0-inf) by 25% and 69%, respectively. Increased plasma concentrations of berotralstat may increase the risk of adverse effects, including the potential for QT prolongation. Berotralstat may cause concentration-dependent prolongation of the Fridericia-corrected QT interval (QTcF). A mean increase in the QTcF interval of 15.9 milliseconds has been reported at three times the recommended dose of berotralstat; however, berotralstat has not been shown to prolong the QT interval to any clinically relevant extent when administered at the recommended daily dose of 150 mg.

MANAGEMENT: During concomitant use of berotralstat with drugs that are substrates of CYP450 3A4, particularly those with a narrow therapeutic index, clinical and laboratory monitoring for patient response and tolerance and individual dose adjustments as needed are recommended. Conversely, while no dose adjustments of berotralstat are recommended, monitoring for adverse events may be advisable during concomitant use of berotralstat with drugs that are also P-gp and/or BCRP inhibitors. Patients should be advised to contact their physician if they experience any undue adverse effects from their medications. Patients should seek prompt medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, lightheadedness, fainting, palpitations, irregular heartbeat, shortness of breath, or syncope. In addition, the prescribing information for concomitant medications should be consulted and dosages adjusted as needed.