Study of Bictegravir/Emtricitabine/Tenofovir Alafenamide Fixed Dose Combination in Adolescents and Children With Human Immunodeficiency Virus-1

HIV-1 Infection Clinical Trial

Official title:

A Phase 2/3, Open-Label Study of the Pharmacokinetics, Safety, and Antiviral Activity of the GS-9883/Emtricitabine/Tenofovir Alafenamide (GS-9883/F/TAF) Fixed Dose Combination (FDC) in HIV-1 Infected Adolescents and Children

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT02881320
• Other study ID #: GS-US-380-1474
• Secondary ID: 2016-002345-39
• Status: Recruiting
• Phase: Phase 2/Phase 3
• Start date: September 21, 2016
• Est. completion date: December 2024

Study information

• Verified date: April 2024
• Source: Gilead Sciences
• Contact: Gilead Study Team
• Email: GS-US-380-1474[@]gilead.com
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

The goals of this clinical study are to learn how Bictegravir/Emtricitabine/Tenofovir Alafenamide fixed dose combination (FDC) interacts with the body, confirm the dose, and also to learn more about the safety and tolerability of Bictegravir/Emtricitabine/Tenofovir Alafenamide FDC in adolescents and children with HIV-1.

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 172
• Est. completion date: December 2024
• Est. primary completion date: June 2024
• Accepts healthy volunteers: No
• Gender: All
• Age group: 1 Month to 17 Years

Eligibility

Key Inclusion Criteria:

Cohort 1: HIV-1 infected adolescents (12 to < 18 years of age and screening weight = 35 kg) who are virologically suppressed for = 6 months prior to screening. Cohort 2: HIV-1 infected children (6 to < 12 years of age and screening weight = 25 kg) who are virologically suppressed for = 6 months prior to screening. Cohort 3: HIV-1 infected children (= 2 years of age and screening weight of = 14 to < 25 kg) who are virologically suppressed for = 6 months prior to screening. Cohort 4 Group 1: HIV-1 infected children (= 2 years of age and screening weight of = 14 to < 25 kg) who are virologically suppressed for = 6 months prior to screening and unable to swallow tablets.

• Documented plasma HIV-1 ribonucleic acid (RNA) < 50 copies/mL on a stable regimen (or undetectable HIV-1 RNA level according to the local assay being used if the limit of detection is = 50 copies/mL) for = 6 months preceding the Screening visit. Unconfirmed virologic elevations of = 50 copies/mL (transient detectable viremia, or "blip") prior to screening are acceptable. If the lower limit of detection of the local HIV-1 RNA assay is < 50 copies/mL (eg, < 20 copies/mL), the plasma HIV-1 RNA level cannot exceed 50 copies/mL on two consecutive HIV-1 RNA tests.
• Stable antiretroviral regimen of 2 nucleoside reverse transcriptase inhibitors (NRTIs) in combination with a third agent for a minimum of 6 months prior to the screening visit. Individuals undergoing dose modifications to their antiretroviral regimen for growth or who are switching medication formulation(s) are considered to be on a stable antiretroviral regimen.
• Estimated glomerular filtration rate (eGFR) = 90 mL/min/1.73 m^2 according to the Schwartz Formula.
• No documented or suspected resistance to emtricitabine (FTC), tenofovir (TFV), or integrase strand transfer inhibitors (INSTIs) including, but not limited to, the reverse transcriptase resistance mutations K65R and M184V/I. Cohort 4 Group 2-4: HIV-1 infected children (= 1 month of age and screening weight of = 3 to < 14 kg) who are treatment naive or on antiretroviral (ARV) treatment for = 1 month prior to screening.
• Positive confirmatory HIV test (confirmatory nucleic acid-based testing if < 18 months of age).
• On a stable ARV regimen for = 1 month or treatment naive (Individual is considered treatment naive if ARVs were given for prevention of mother-to-child transmission but not for HIV treatment).
• For < 1 year of age, eGFR = the minimum normal values for age according to the information below using the Schwartz Formula,
• 30 mL/min/1.73 m^2 for age > 4 weeks to = 95 days.
• 39 mL/min/1.73 m^2 for age = 96 days to = 6 months.
• 49 mL/min/1.73 m^2 for age > 6 months to < 12 months.
• For = 1 year of age, eGFR = 90 mL/min/1.73 m^2 using the Schwartz Formula.
• No documented or suspected resistance to FTC, TFV, or INSTIs including, but not limited to, the reverse transcriptase resistance mutation K65R.
• For individuals < 14 kg, M184V/I AND HIV-1 RNA < 50 copies/mL will be allowed. Individuals with HIV-1 RNA > 50 copies/mL should not have FTC, TFV, or INSTI resistance mutations.
• Last dose of nevirapine (NVP) or efavirenz (EFV), if applicable, = 14 days prior to enrollment. Note: Other protocol defined Inclusion/Exclusion criteria may apply.

Related Conditions & MeSH terms

• HIV-1 Infection

Intervention

Drug:
• B/F/TAF (Adult Strength)
50/200/25 mg FDC tablets administered orally once daily without regard to food.
• B/F/TAF (Low Dose)
30/120/15 mg FDC tablets administered orally once daily without regard to food.
• B/F/TAF (TOS)
2 x B/F/TAF 15/60/7.5 mg (total daily dose 30/120/15 mg) FDC tablets administered orally as TOS, once daily.
• B/F/TAF (TOS)
2 x B/F/TAF 3.75/15/1.88 mg (total daily dose 15/60/7.52 mg) FDC tablets administered orally as TOS, twice daily.
• B/F/TAF (TOS)
1 x B/F/TAF 3.75/15/1.88 mg (total daily dose 7.5/30/3.76 mg) FDC tablets administered orally as TOS, twice daily.
• B/F/TAF (TOS)
1 x B/F/TAF 1.88/7.5/0.94 mg (total daily dose 3.76/15/1.88 mg) FDC tablets administered orally as TOS, twice daily

Locations

Country	Name	City	State
South Africa	Department of Paediatrics and Child Health	Bloemfontein
South Africa	Be Part Ypluntu Centre	Cape Town
South Africa	FAMCRU, Ward J8	CapeTown
South Africa	Dr. J Fourie Medical Centre	Dundee
South Africa	Enhancing Care Foundation, Durban International Clinical Research Site	Durban
South Africa	Clinical HIV Research Unit(CHRU), Wits Health Consortium, Department of Medicine, University of the Witwatersrand	Johannesburg
South Africa	Empilweni Service and Research Unit (ESRU)	Johannesburg
South Africa	Wits RHI Shandukani Research Centre, Wits Reproductive Health & HIV Institute	Johannesburg
South Africa	VX Pharma(Pty) Ltd	Pretoria
South Africa	Perinatal HIV Research Unit	Soweto
Thailand	Faculty of Medicine Siriraj Hospital, Mahidol University	Bangkok
Thailand	The HIV Netherlands Australia Thailand Research Collaboration	Bangkok
Thailand	Faculty of Medicine, Khon Kaen University	Khon Kaen
Uganda	Baylor College of Medicine Children's Foundation - Uganda	Kampala
Uganda	Joint Clinical Research Centre	Kampala
Uganda	Makerere University, Johns Hopkins (MU-JHU) Research Collaboration	Kampala
United States	Grady Health System Ponce Center Family and Youth Clinic	Atlanta	Georgia
United States	Wayne Pediatric Clinic	Detroit	Michigan
United States	Duke Children's Health Center, Pediatric Infectious Diseases	Durham	North Carolina
United States	Midway Immunology and Research Center	Fort Pierce	Florida
United States	University of Florida Health	Gainesville	Florida
United States	St. Jude Children's Research Hospital	Memphis	Tennessee
United States	Bellevue Hospital	New York	New York
United States	St. Christopher's Hospital for Children/Section of Immunology	Philadelphia	Pennsylvania
United States	USF Clinic at Children's Medical Services (study visits and drug storage)	Tampa	Florida
United States	Children's National Health System	Washington	District of Columbia

Sponsors (1)

Lead Sponsor	Collaborator
Gilead Sciences

Countries where clinical trial is conducted

United States,  South Africa,  Thailand,  Uganda, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	PK Parameter: AUCtau of Bictegravir	AUCtau is defined as concentration of drug over time (the area under the concentration verses time curve over the dosing interval). Cohorts 1 & 2 Part A will participate in an Intensive PK Evaluation at Week 2 or Week 4. Samples will be collected at 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, and 24 hours post-dose.; Cohort 3 Part A will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, and 24 hours post-dose.; Cohort 4 Groups 2, 3, and 4 participants will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose) 0.5, 1, 2, 4, and 8 hours post-dose.	Week 2 or Week 4 for Cohorts 1 & 2: 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, & 24 hours postdose; Week 2 for Cohort 3: 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, & 24 hours post-dose; Week 2 for Cohort 4: 0 (predose) 0.5, 1, 2, 4, & 8 hours postdose
Primary	PK Parameter: Ctau of Bictegravir	Ctau is defined as the observed drug concentration at the end of the dosing interval. Cohorts 1 & 2 Part A will participate in an Intensive PK Evaluation at Week 2 or Week 4. Samples will be collected at 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, and 24 hours post-dose.; Cohort 3 Part A will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, and 24 hours post-dose.; Cohort 4 Groups 2, 3, and 4 participants will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose) 0.5, 1, 2, 4, and 8 hours post-dose.	Week 2 or Week 4 for Cohorts 1 & 2: 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, & 24 hours postdose; Week 2 for Cohort 3: 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, & 24 hours post-dose; Week 2 for Cohort 4: 0 (predose) 0.5, 1, 2, 4, & 8 hours postdose
Primary	PK Parameter: AUClast of TAF (Cohort 4)	AUClast is defined as area under the concentration versus time curve from time zero to the last quantifiable concentration.; Cohort 4 Groups 2, 3, and 4 participants will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose) 0.5, 1, 2, 4, and 8 hours post-dose.	Week 2 for Cohort 4: 0 (predose) 0.5, 1, 2, 4, & 8 hours postdose
Primary	PK Parameter: Cmax of TAF (Cohort 4)	Cmax is defined as maximum observed concentration of drug. Cohort 4 Groups 2, 3, and 4 participants will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose) 0.5, 1, 2, 4, and 8 hours post-dose.	Week 2 for Cohort 4: 0 (predose) 0.5, 1, 2, 4, & 8 hours postdose
Primary	Percentage of Participants Experiencing Treatment-Emergent Adverse Events (AEs) Through Week 24		Up to 24 weeks
Primary	Percentage of Participants Experiencing Treatment-Emergent Laboratory Abnormalities Through Week 24		Up to 24 weeks
Secondary	Proportion of Participants with Plasma HIV-1 RNA < 50 copies/mL at Week 24 as Defined by the US FDA-Defined Snapshot Algorithm		Week 24
Secondary	Proportion of Participants with Plasma HIV-1 RNA < 50 copies/mL at Week 48 as Defined by the US FDA-Defined Snapshot Algorithm		Week 48
Secondary	Change from Baseline in CD4+ Cell Counts at Week 24		Baseline, Week 24
Secondary	Change from Baseline in CD4+ Cell Counts at Week 48		Baseline, Week 48
Secondary	Change from Baseline in CD4+ Cell Count Percentages at Week 24		Baseline, Week 24
Secondary	Change from Baseline in CD4+ Cell Count Percentages at Week 48		Baseline, Week 48
Secondary	PK Parameter: Tmax of Bictegravir	Tmax is defined as the time (observed time point) of Cmax. Cohorts 1 & 2 Part A will participate in an Intensive PK Evaluation at Week 2 or Week 4. Samples will be collected at 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, and 24 hours post-dose.; Cohort 3 Part A will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, and 24 hours post-dose.; Cohort 4 Groups 2, 3, and 4 participants will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose) 0.5, 1, 2, 4, and 8 hours post-dose.	Week 2 or Week 4 for Cohorts 1 & 2: 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, & 24 hours postdose; Week 2 for Cohort 3: 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, & 24 hours post-dose; Week 2 for Cohort 4: 0 (predose) 0.5, 1, 2, 4, & 8 hours postdose
Secondary	PK Parameter: Cmax of Bictegravir	Cmax is defined as the maximum observed concentration of drug. Cohorts 1 & 2 Part A will participate in an Intensive PK Evaluation at Week 2 or Week 4. Samples will be collected at 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, and 24 hours post-dose.; Cohort 3 Part A will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, and 24 hours post-dose.; Cohort 4 Groups 2, 3, and 4 participants will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose) 0.5, 1, 2, 4, and 8 hours post-dose.	Week 2 or Week 4 for Cohorts 1 & 2: 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, & 24 hours postdose; Week 2 for Cohort 3: 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, & 24 hours post-dose; Week 2 for Cohort 4: 0 (predose) 0.5, 1, 2, 4, & 8 hours postdose
Secondary	PK Parameter: AUClast of Bictegravir	AUClast is defined as the area under the concentration of drug from time zero to the last observable concentration. Cohorts 1 & 2 Part A will participate in an Intensive PK Evaluation at Week 2 or Week 4. Samples will be collected at 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, and 24 hours post-dose.; Cohort 3 Part A will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, and 24 hours post-dose.; Cohort 4 Groups 2, 3, and 4 participants will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose) 0.5, 1, 2, 4, and 8 hours post-dose.	Week 2 or Week 4 for Cohorts 1 & 2: 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, & 24 hours postdose; Week 2 for Cohort 3: 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, & 24 hours post-dose; Week 2 for Cohort 4: 0 (predose) 0.5, 1, 2, 4, & 8 hours postdose
Secondary	PK Parameter: T1/2 of Bictegravir	T1/2 is defined as the estimate of the terminal elimination half-life of the drug. Cohorts 1 & 2 Part A will participate in an Intensive PK Evaluation at Week 2 or Week 4. Samples will be collected at 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, and 24 hours post-dose.; Cohort 3 Part A will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, and 24 hours post-dose.; Cohort 4 Groups 2, 3, and 4 participants will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose) 0.5, 1, 2, 4, and 8 hours post-dose.	Week 2 or Week 4 for Cohorts 1 & 2: 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, & 24 hours postdose; Week 2 for Cohort 3: 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, & 24 hours post-dose; Week 2 for Cohort 4: 0 (predose) 0.5, 1, 2, 4, & 8 hours postdose
Secondary	PK Parameter: Apparent Clearance (CL) of Bictegravir	CL is defined as the systemic clearance of the drug following study drug administration. Cohorts 1 & 2 Part A will participate in an Intensive PK Evaluation at Week 2 or Week 4. Samples will be collected at 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, and 24 hours post-dose.; Cohort 3 Part A will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, and 24 hours post-dose.; Cohort 4 Groups 2, 3, and 4 participants will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose) 0.5, 1, 2, 4, and 8 hours post-dose.	Week 2 or Week 4 for Cohorts 1 & 2: 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, & 24 hours postdose; Week 2 for Cohort 3: 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, & 24 hours post-dose; Week 2 for Cohort 4: 0 (predose) 0.5, 1, 2, 4, & 8 hours postdose
Secondary	PK Parameter: Apparent Vz of Bictegravir	Vz is defined as the volume of distribution of the drug after study drug administration. Cohorts 1 & 2 Part A will participate in an Intensive PK Evaluation at Week 2 or Week 4. Samples will be collected at 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, and 24 hours post-dose.; Cohort 3 Part A will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, and 24 hours post-dose.; Cohort 4 Groups 2, 3, and 4 participants will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose) 0.5, 1, 2, 4, and 8 hours post-dose.	Week 2 or Week 4 for Cohorts 1 & 2: 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, & 24 hours postdose; Week 2 for Cohort 3: 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, & 24 hours post-dose; Week 2 for Cohort 4: 0 (predose) 0.5, 1, 2, 4, & 8 hours postdose
Secondary	PK Parameter: AUCtau of TAF and FTC	AUCtau is defined as concentration of drug over time (the area under the concentration verses time curve over the dosing interval). Cohorts 1 & 2 Part A will participate in an Intensive PK Evaluation at Week 2 or Week 4. Samples will be collected at 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, and 24 hours post-dose.; Cohort 3 Part A will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, and 24 hours post-dose.; Cohort 4 Groups 2, 3, and 4 participants will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose) 0.5, 1, 2, 4, and 8 hours post-dose.	Week 2 or Week 4 for Cohorts 1 & 2: 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, & 24 hours postdose; Week 2 for Cohort 3: 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, & 24 hours post-dose; Week 2 for Cohort 4: 0 (predose) 0.5, 1, 2, 4, & 8 hours postdose
Secondary	PK Parameter: AUClast of TAF and FTC (Cohorts 1, 2, and 3)	AUClast is defined as the area under the concentration of drug from time zero to the last observable concentration. Cohorts 1 & 2 Part A will participate in an Intensive PK Evaluation at Week 2 or Week 4. Samples will be collected at 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, and 24 hours post-dose.; Cohort 3 Part A will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, and 24 hours post-dose.	Week 2 or Week 4 for Cohorts 1 & 2: 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, & 24 hours postdose; Week 2 for Cohort 3: 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, & 24 hours post-dose
Secondary	PK Parameter: AUClast of FTC (Cohorts 4)	AUClast is defined as area under the concentration versus time curve from time zero to the last quantifiable concentration.; Cohort 4 Groups 2, 3, and 4 participants will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose) 0.5, 1, 2, 4, and 8 hours post-dose.	Week 2 for Cohort 4: 0 (predose) 0.5, 1, 2, 4, & 8 hours postdose
Secondary	PK Parameter: Cmax of TAF and FTC (Cohorts 1, 2, and 3)	Cmax is defined as the maximum observed concentration of drug. Cohorts 1 & 2 Part A will participate in an Intensive PK Evaluation at Week 2 or Week 4. Samples will be collected at 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, and 24 hours post-dose.; Cohort 3 Part A will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, and 24 hours post-dose.	Week 2 or Week 4 for Cohorts 1 & 2: 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, & 24 hours postdose; Week 2 for Cohort 3: 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, & 24 hours post-dose
Secondary	PK Parameter: Cmax of FTC (Cohorts 4)	Cmax is defined as maximum observed concentration of drug. Cohort 4 Groups 2, 3, and 4 participants will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose) 0.5, 1, 2, 4, and 8 hours post-dose.	Week 2 for Cohort 4: 0 (predose) 0.5, 1, 2, 4, & 8 hours postdose
Secondary	PK Parameter: Ctau of TAF and FTC	Ctau is defined as the observed drug concentration at the end of the dosing interval. Cohorts 1 & 2 Part A will participate in an Intensive PK Evaluation at Week 2 or Week 4. Samples will be collected at 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, and 24 hours post-dose.; Cohort 3 Part A will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, and 24 hours post-dose.; Cohort 4 Groups 2, 3, and 4 participants will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose) 0.5, 1, 2, 4, and 8 hours post-dose.	Week 2 or Week 4 for Cohorts 1 & 2: 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, & 24 hours postdose; Week 2 for Cohort 3: 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, & 24 hours post-dose; Week 2 for Cohort 4: 0 (predose) 0.5, 1, 2, 4, & 8 hours postdose
Secondary	PK Parameter: Tmax of TAF and FTC	Tmax is defined as the time (observed time point) of Cmax. Cohorts 1 & 2 Part A will participate in an Intensive PK Evaluation at Week 2 or Week 4. Samples will be collected at 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, and 24 hours post-dose.; Cohort 3 Part A will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, and 24 hours post-dose.; Cohort 4 Groups 2, 3, and 4 participants will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose) 0.5, 1, 2, 4, and 8 hours post-dose.	Week 2 or Week 4 for Cohorts 1 & 2: 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, & 24 hours postdose; Week 2 for Cohort 3: 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, & 24 hours post-dose; Week 2 for Cohort 4: 0 (predose) 0.5, 1, 2, 4, & 8 hours postdose
Secondary	PK Parameter: T1/2 of TAF and FTC	T1/2 is defined as the estimate of the terminal elimination half-life of the drug. Cohorts 1 & 2 Part A will participate in an Intensive PK Evaluation at Week 2 or Week 4. Samples will be collected at 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, and 24 hours post-dose.; Cohort 3 Part A will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, and 24 hours post-dose.; Cohort 4 Groups 2, 3, and 4 participants will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose) 0.5, 1, 2, 4, and 8 hours post-dose.	Week 2 or Week 4 for Cohorts 1 & 2: 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, & 24 hours postdose; Week 2 for Cohort 3: 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, & 24 hours post-dose; Week 2 for Cohort 4: 0 (predose) 0.5, 1, 2, 4, & 8 hours postdose
Secondary	PK Parameter: Apparent CL of TAF and FTC	CL is defined as the systemic clearance of the drug following study drug administration. Cohorts 1 & 2 Part A will participate in an Intensive PK Evaluation at Week 2 or Week 4. Samples will be collected at 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, and 24 hours post-dose.; Cohort 3 Part A will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, and 24 hours post-dose.; Cohort 4 Groups 2, 3, and 4 participants will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose) 0.5, 1, 2, 4, and 8 hours post-dose.	Week 2 or Week 4 for Cohorts 1 & 2: 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, & 24 hours postdose; Week 2 for Cohort 3: 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, & 24 hours post-dose; Week 2 for Cohort 4: 0 (predose) 0.5, 1, 2, 4, & 8 hours postdose
Secondary	PK Parameter: Apparent Vz of TAF and FTC	Vz is defined as the volume of distribution of the drug after study drug administration. Cohorts 1 & 2 Part A will participate in an Intensive PK Evaluation at Week 2 or Week 4. Samples will be collected at 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, and 24 hours post-dose.; Cohort 3 Part A will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, and 24 hours post-dose.; Cohort 4 Groups 2, 3, and 4 participants will participate in an Intensive PK evaluation at Week 2. Samples will be collected at 0 (pre-dose) 0.5, 1, 2, 4, and 8 hours post-dose.	Week 2 or Week 4 for Cohorts 1 & 2: 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, & 24 hours postdose; Week 2 for Cohort 3: 0 (pre-dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, 8, & 24 hours post-dose; Week 2 for Cohort 4: 0 (predose) 0.5, 1, 2, 4, & 8 hours postdose
Secondary	Percentage of Participants Experiencing Treatment-Emergent Adverse Events Through Week 48		Up to 48 weeks
Secondary	Percentage of Participants Experiencing Treatment-Emergent Laboratory Abnormalities Through Week 48		Up to 48 weeks
Secondary	Acceptability of B/F/TAF Formulation at Day 1 (All Cohorts)	Participants or legal guardian will be asked: if study drug shape and size were acceptable (for Cohort 1 and Cohort 2); about ease of swallowability and the shape and size of study drug when swallowed (for Cohort 3); about their understanding of instructions, preparation of the study drug formulation and study drug administration and taste (for Cohort 4)	Day 1
Secondary	Palatability of B/F/TAF Formulation at Day 1 (All Cohorts)	Participants or legal guardian will be asked about the study drug taste (All Cohorts)	Day 1
Secondary	Acceptability of B/F/TAF Formulation at Week 4 (All Cohorts)	Participants or legal guardian will be asked: if study drug shape and size were acceptable (for Cohort 1 and Cohort 2); about ease of swallowability and the shape and size of study drug when swallowed (for Cohort 3).; about their understanding of instructions, preparation of the study drug formulation and study drug administration and taste (for Cohort 4)	Week 4
Secondary	Palatability of B/F/TAF Formulation at Week 4 (All Cohorts)	Participants or legal guardian will be asked about the study drug taste (All Cohorts)	Week 4
Secondary	Acceptability of B/F/TAF Formulation at Week 24 (Cohort 3 and Cohort 4)	Participants or legal guardian will be asked: about ease of swallowability and the shape and size of study drug when swallowed (for Cohort 3).; about their understanding of instructions, preparation of the study drug formulation and study drug administration and taste (for Cohort 4)	Week 24
Secondary	Palatability of B/F/TAF Formulation at Week 24 (Cohort 3 and Cohort 4)	Participants or legal guardian will be asked about the study drug taste	Week 24
Secondary	Acceptability of B/F/TAF Formulation at Week 48 (Cohort 3 and Cohort 4)	Participants or legal guardian will be asked: about ease of swallowability and the shape and size of study drug when swallowed (for Cohort 3).; about their understanding of instructions, preparation of the study drug formulation and study drug administration and taste (for Cohort 4)	Week 48
Secondary	Palatability of B/F/TAF Formulation at Week 48 (Cohort 3 and Cohort 4)	Participants or legal guardian will be asked about the study drug taste	Week 48
Secondary	Acceptability of B/F/TAF Formulation at Week 1 (Cohort 4)	Participants or legal guardian will be asked about their understanding of instructions, preparation of the study drug formulation and study drug administration and taste	Week 1
Secondary	Palatability of B/F/TAF Formulation at Week 1 (Cohort 4)	Participants or legal guardian will be asked about the study drug taste	Week 1
Secondary	Acceptability of B/F/TAF Formulation at Week 2 (Cohort 4)	Participants or legal guardian will be asked about their understanding of instructions, preparation of the study drug formulation and study drug administration and taste	Week 2
Secondary	Palatability of B/F/TAF Formulation at Week 2 (Cohort 4)	Participants or legal guardian will be asked about the study drug taste	Week 2