Darunavir/cobicistat should not be used in combination with another antiretroviral that requires pharmacoenhancement since dosing recommendations for such combination have not been established. Darunavir/cobicistat should not be used concurrently with regimens containing cobicistat.

Darunavir/cobicistat is not recommended in combination with other antiretroviral drugs that require pharmacokinetic boosting (i.e., elvitegravir) because dosing recommendations for such combinations have not been established and co-administration may result in decreased plasma concentrations of the antiretroviral agents, leading to loss of therapeutic effect and development of resistance.

Stribild is indicated for use as a complete regimen for the treatment of HIV 1 infection and must not be administered with other antiretroviral products.

Stribild is a complete regimen for the treatment of HIV-1 infection; therefore, Stribild should not be administered with other antiretroviral medications for treatment of HIV-1 infection.

Coadministration of elvitegravir/cobicistat/emtricitabine/tenofovir-DF (Stribild, 150/150/200/300 mg, once daily) with darunavir (800 mg, once daily) was studied in a parallel groups of HIV positive patients (Stribild + DRV n=24; Stribild alone n=32; darunavir/cobicistat (800/150 mg once daily) n=32). Elvitegravir C24 decreased by 6.6% in the presence of darunavir, but cobicistat and darunavir C24s were unchanged. Due to the limitations of this study, drug-drug interactions between Stribild and darunavir cannot be entirely ruled out, but this study provides evidence that this combination may be safe.

The pharmacokinetic, efficacy, and safety of Genvoya and darunavir (800 mg once daily) versus a darunavir-based multi-tablet regimen was evaluated in treatment-experienced (2 and 3 class-drug regimen resistance), virologically suppressed, HIV-infected adults in a 48-week, multi-centre, randomized, open label study (GS-US-292-0119). Elvitegravir Ctrough was >10-fold above the elvitegravir protein binding-adjusted IC95 (45 ng/ml) and darunavir Ctrough was >22-fold above the darunavir protein binding-adjusted IC50 (55 ng/ml). The patients remained virologically suppressed and did not develop resistance in the Genvoya arm over 48 weeks of therapy. In addition, no subjects discontinued treatment due to adverse events. A switch to Genvoya and darunavir resulted in improvement in quantitative proteinuria compared with darunavir-containing regimens. The authors conclude that for treatment experienced individuals with >2 class resistance on complex high-pill burden regimens, switching to Genvoya and darunavir may provide a simple once-daily, two-pill option with superior efficacy and comparable tolerability.