Drug Interactions between atazanavir and elbasvir / grazoprevir

CONTRAINDICATED: Coadministration with inhibitors of organic anion transporting polypeptides (OATP) 1B1 and/or 1B3 may significantly increase the plasma concentrations of grazoprevir, which is a substrate of the hepatic uptake transporters. In 12 study subjects, administration of a single 200 mg dose of grazoprevir with a single 600 mg intravenous dose of rifampin, a potent OATP1B1 inhibitor, resulted in greater than 10-fold increases in grazoprevir peak plasma concentration (Cmax) and systemic exposure (AUC) compared to administration of grazoprevir alone. A single 600 mg oral dose of rifampin administered during multiple-dosing of grazoprevir 200 mg once daily increased the Cmax and AUC of grazoprevir by 6.5- and 8.4-fold, respectively. Pharmacokinetic studies with other OATP1B1 inhibitors have reported similar results. In one study, administration of grazoprevir 200 mg once daily with atazanavir/ritonavir 300 mg/100 mg once daily increased grazoprevir Cmax, AUC and Cmin by 6.2-, 10.6- and 11.6-fold, respectively (n=12). Likewise, administration with darunavir/ritonavir 600 mg/100 mg twice daily increased grazoprevir Cmax, AUC and Cmin by 5.3-, 7.5- and 8.1-fold, respectively (n=13), while administration with lopinavir/ritonavir 400 mg/100 mg twice daily increased grazoprevir Cmax, AUC and Cmin by 7.3-, 12.9- and 21.7-fold, respectively (n=13). A single 400 mg dose of cyclosporine increased grazoprevir Cmax, AUC and Cmin by 17.0-, 15.2- and 3.4-fold, respectively (n=14). High plasma levels of grazoprevir may increase the risk of adverse effects such as alanine aminotransferase (ALT) elevations.

MANAGEMENT: Concomitant use of elbasvir-grazoprevir with OATP 1B1 or 1B3 inhibitors is considered contraindicated.

GENERALLY AVOID: Coadministration with potent inhibitors of CYP450 3A4 may significantly increase the plasma concentrations of elbasvir, which is a substrate of the isoenzyme. In 10 study subjects, administration of elbasvir (50 mg once daily) with the potent CYP450 3A4 inhibitors atazanavir/ritonavir (300 mg/100 mg once daily) increased elbasvir peak plasma concentration (Cmax), systemic exposure (AUC) and trough plasma concentration (Cmin) by 4.15-fold, 4.76-fold and 6.45-fold, respectively, compared to elbasvir alone. Likewise, administration with lopinavir/ritonavir 400 mg/100 mg twice daily increased elbasvir Cmax, AUC, and Cmin by 2.87-, 3.71-, and 4.58-fold, respectively (n=10), while administration with darunavir/ritonavir 600 mg/100 mg twice daily increased elbasvir Cmax, AUC, and Cmin by 1.67-, 1.66-, and 1.82-fold, respectively (n=10). Another potent CYP450 3A4 inhibitor, ketoconazole (400 mg once daily), increased the Cmax, AUC, and Cmin of a single 50 mg dose of elbasvir by 1.29-, 1.80, and 1.89-fold, respectively (n=7).

MANAGEMENT: Concomitant use of elbasvir with potent CYP450 3A4 inhibitors should generally be avoided.