Pharmacokinetic interactions between cobicistat-boosted elvitegravir and darunavir in HIV-infected patients.

Objectives: To evaluate if there are significant drug-drug interactions between cobicistat-boosted elvitegravir and 800 mg darunavir once daily taken simultaneously, as has been suggested previously.

Methods: The study population consisted of three groups of unselected volunteers taking a regimen of elvitegravir, cobicistat, emtricitabine and tenofovir disoproxil fumarate (150, 150, 200 and 300 mg, respectively) co-formulated in a single tablet plus 800 mg darunavir (group A); only co-formulated elvitegravir, cobicistat, emtricitabine and tenofovir disoproxil fumarate (group B); and cobicistat-boosted darunavir (800 mg darunavir + 150 mg cobicistat) plus two nucleos(t)ide analogues (group C). Elvitegravir, cobicistat and darunavir concentrations at the end of the dosing interval ( C 24 ) were quantified using a validated LC with tandem MS method.