Bioequivalence of the Once-Daily Single-Tablet Regimen of Darunavir, Cobicistat, Emtricitabine, and Tenofovir Alafenamide Compared to Combined Intake of the Separate Agents and the Effect of Food on Bioavailability.

The effect of food on the bioavailability of the components of the once-daily, single-tablet human immunodeficiency virus (HIV) type 1 regimen containing darunavir (DRV 800 mg), cobicistat (COBI 150 mg), emtricitabine (FTC 200 mg), and tenofovir alafenamide (TAF 10 mg) (D/C/F/TAF) (NCT02475135) and the bioequivalence of D/C/F/TAF versus combined intake of the separate agents (NCT02578550) were evaluated. These were 2 phase 1, open-label, randomized, 2-period crossover studies (7-day washout between treatments) in HIV-negative healthy volunteers. Twenty-four participants each received a single dose of D/C/F/TAF in fasted conditions (test) or after a standardized high-fat breakfast (reference). Ninety-six participants each received a single dose of D/C/F/TAF (test) or combined intake of a single DRV 800-mg tablet, a COBI 150-mg tablet, and an FTC/TAF 200/10-mg tablet (reference), both after a standardized regular-calorie, regular-fat breakfast. Pharmacokinetic profiles for all D/C/F/TAF components, safety, and tolerability were assessed. Following D/C/F/TAF in fasted conditions, DRV peak concentration, area under the concentration-time curve from time of administration until the last time point with a measurable concentration (AUC)last , and extrapolated to infinity (AUCinf ) were lower by 45%, 34%, and 30%, respectively, compared with fed conditions, with no clinically relevant differences in COBI, FTC, or TAF exposures between fed and fasted conditions. In the bioequivalence study 90% confidence intervals of the geometric mean ratios of all main pharmacokinetic parameters were within the 80.00% to 125.00% bioequivalence limits for DRV, COBI, FTC, and TAF. No grade 3/4 adverse events (AEs), serious AEs, deaths, or discontinuations due to AEs occurred. D/C/F/TAF is bioequivalent to combined administration of the separate agents. Consistent with other (co)formulations of DRV, DRV exposure was lower in fasted than in fed conditions as evaluated when taken with food, so D/C/F/TAF should be taken with food.