STRIBILD label updated

Recently the STRIBILD® (elvitegravir, cobicistat, emtricitabine, tenofovir disoproxil fumarate) tablet label was updated to include drug-drug interaction information with quetiapine and ledipasvir/sofosbuvir and to update section 12.2 with information on the effects on serum creatinine. The changes to the label are summarized below.

• Initiation of STRIBILD in patients taking quetiapine: 

Consider alternative antiretroviral therapy to avoid increases in quetiapine exposure.  If coadministration is necessary, reduce the quetiapine dose to 1/6 of the current dose and monitor for quetiapine-associated adverse reactions.  Refer to the quetiapine prescribing information for recommendations on adverse reaction monitoring.

• Initiation of quetiapine in patients taking STRIBILD:

Refer to the quetiapine prescribing information for initial dosing and titration of quetiapine.

• The safety of increased tenofovir concentrations in the setting of HARVONI® (ledipasivir/sofosbuvir) and STRIBILD has not been established.  Coadministration is not recommended.

12.2  Pharmacodynamics

Effects on Serum Creatinine

The effect of cobicistat on serum creatinine was investigated in a Phase 1 study in subjects with an eGFR of at least 80 mL per minute (N=18) and with an eGFR of 50 to 79 mL per minute (N=12). A statistically significant change of eGFRCG from baseline was observed after 7 days of treatment with cobicistat 150 mg among subjects with an eGFR of at least 80 mL per minute (-9.9 ± 13.1 mL/min) and subjects with an eGFR of 50 to 79 mL per minute (-11.9 ± 7.0 mL per minute). These decreases in eGFRCG were reversible after cobicistat was discontinued. The actual glomerular filtration rate, as determined by the clearance of probe drug iohexol, was not altered from baseline following treatment of cobicistat among subjects with an eGFR of at least 50 mL per minute, indicating cobicistat inhibits tubular secretion of creatinine, reflected as a reduction in eGFRCG, without affecting the actual glomerular filtration rate.

You will be able to view the complete label at drugs@fda or dailymed.

Richard Klein
Office of Health and Constituent Affairs
Food and Drug Administration

Kimberly Struble
Division of Antiviral Products
Food and Drug Administration

Steve Morin
Office of Health and Constituent Affairs
Food and Drug Administration

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