Relative Bioavailability and Food Effect for Darunavir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Fixed Dose Combination

The purpose of this study is to evaluate the pharmacokinetics and relative bioavailability of Emtricitabine (FTC) and Tenofovir alafenamide (TAF) when administered as a fixed-dose combination (FDC) with darunavir (DRV) and cobicistat (COBI) (darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) relative to administration as an FDC with Elvitegravir (EVG) and COBI (Elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide), under fed conditions in healthy subjects (Panel 1); evaluate the single-dose pharmacokinetics and relative bioavailability of DRV, COBI, FTC and TAF when administered as an FDC (D/C/F/TAF) or as separate agents (D+C+FTC/TAF), under fed conditions in healthy subjects (Panel 2) and to evaluate the impact of food (fasting or high-fat breakfast) on the single-dose pharmacokinetics of DRV, COBI, FTC, and TAF when administered as an FDC (D/C/F/TAF) in healthy subjects (Panel 3).

This is a Phase 1, 3-panel, open-label, randomized, 2-way crossover study in healthy subjects. Healthy subjects will be divided over 3 panels (Panel 1, 2 and 3). Subjects will be randomized within each panel. In each panel, during 2 subsequent sessions, each subject will receive 2 treatments (Treatments A and B in Panel 1, Treatments C and D in Panel 2, and Treatments E and F in Panel 3). Each treatment is defined as follows: Treatment A: single oral dose of D/C/F/TAF 800/150/200/10 milligram (mg) as FDC tablet under fed conditions (standardized regular breakfast); Treatment B: single oral dose of E/C/F/TAF 150/150/200/10 mg as FDC tablet under fed conditions; Treatment C: single oral dose of D/C/F/TAF 800/150/200/10 mg as FDC tablet under fed conditions; Treatment D: single oral dose of DRV as 800-mg tablet, FTC/TAF as 200/10 mg tablet and COBI 150 mg tablet under fed conditions. Treatment E: single oral dose of D/C/F/TAF 800/150/200/10 mg as FDC tablet, under fasted condition and Treatment F: single oral dose of D/C/F/TAF 800/150/200/10 mg tablet, with a standardized high-fat breakfast. Each treatment will be separated by a washout period of at least 7 days. Primarily pharmacokinetic parameters will be assessed. Subjects' safety will be assessed throughout.

Eligibility Criteria:
Inclusion Criteria:

* Subject must be a non-smoker for at least 3 months prior to selection
* Subject must have a body mass index (BMI, weight in kg divided by the square of height in meters) of 18.5 to 30.0 kg/m\^2, extremes included
* Subject must be healthy on the basis of physical examination, medical history, vital signs, and 12-lead ECG performed at screening. If the results are outside the normal reference ranges, the subject may be included only if they are not listed under the exclusion criteria and if the Investigator judges the abnormalities or deviations from normal to be not clinically significant. This determination must be recorded in the subject's source documents and initialed by the Investigator
* Subject must be healthy on the basis of clinical laboratory tests performed at screening. If the results of the biochemistry panel, hematology, or urinalysis are outside the normal reference ranges, the subject may be included only if the abnormalities or deviations from normal are not listed in the exclusion criteria, and the Investigator judges they are not clinically significant. This determination must be recorded in the subject's source documents and initialed by the Investigator
* Subject must be willing and able to adhere to the prohibitions and restrictions specified in this protocol

Exclusion Criteria:

* Subject has a positive human immunodeficiency virus-1 (HIV-1) or HIV-2 test at screening
* Subject has hepatitis A, B, or C infection (confirmed by a positive hepatitis A antibody immunoglobulin M (IgM), hepatitis B surface antigen, and/or hepatitis C virus antibody, respectively) at screening
* Subject has currently significant and active diarrhea, nausea, or constipation that in the Investigator's opinion could influence drug absorption or bioavailability
* Subject has any history of renal insufficiency
* Subject has known allergies, hypersensitivity, or intolerance to DRV, COBI (GS-9350), EVG (Panel 1 only), FTC, TAF or their excipients