An Open-Label One-way Interaction Clinical Trial to Evaluate the Pharmacokinetic Interactions Between GSK3640254 and Tenofovir Alafenamide/Emtricitabine in Healthy Subjects
Phase: PHASE1
Conditions: HIV Infections
Sponsor: ViiV Healthcare

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TITLE PAGE
Protocol Title: An Open-Label One-way Interaction Clinical Trial to Evaluate the 
Pharmacokinetic Interactions Between GSK3640254 and Tenofovir 
Alafenamide/Emtricitabine in Healthy Subjects
Protocol Number: 208134
Compound Number:
GSK3640254
Study Phase: Phase I
Short Title: Study to Evaluate the Effect of GSK3640254 on the PK of Tenofovir 
Alafenamide/Emtricitabine
US IND Sponsor Name and Legal Registered Address:
ViiV Healthcare Company
Five Moore Drive
P.O. 13398
Research Triangle Park, NC 27709-3398, USA
Telephone: 
In some countries, local law requires that the Clinical Trial sponsor is a local 
company legal entity. In these instances, the appropriate company to be identified as 
Sponsor must be agreed with the global ViiV Healthcare clinical team and signed off 
by the Vice President, Global Research and Medical Strategy 
This study is sponsored by ViiV Healthcare. PPD with GlaxoSmithKline are 
supporting ViiV Healthcare in the conduct of this study.
Medical Monitor Name and Contact Information: Can be found in the Study 
Reference Manual
Regulatory Agency Identifying Number(s):
IND: 139,838
Approval Date: 27-DEC-2018
Copyright 2018 the ViiV Healthcare group of companies. All rights reserved. 
Unauthorized copying or use of this information is prohibited.
 
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TABLE OF CONTENTS
PAGE
1.
PROTOCOL SUMMARY..........................................................................................6
1.1.
Synopsis.......................................................................................................6
1.2.
Schema ........................................................................................................7
1.3.
Schedule of Activities (SoA)..........................................................................8
2.
INTRODUCTION....................................................................................................12
2.1.
Study Rationale ..........................................................................................12
2.2.
Background ................................................................................................12
2.2.1.
Background and Key Safety Data with a Prior Maturation 
Inhibitor........................................................................................12
2.2.2.
Preliminary Safety and Pharmacokinetic Data in Study 
207187 ........................................................................................13
2.2.3.
Preliminary Safety and Pharmacokinetic Data in Study 
208131 ........................................................................................14
2.2.4.
Tenofovir Alafenamide/Emtricitabine............................................14
2.3.
Benefit/Risk Assessment ............................................................................15
2.3.1.
Risk Assessment .........................................................................16
2.3.2.
Benefit Assessment.....................................................................18
2.3.3.
Overall Benefit: Risk Conclusion..................................................18
3.
OBJECTIVES AND ENDPOINTS...........................................................................18
4.
STUDY DESIGN ....................................................................................................19
4.1.
Overall Design ............................................................................................19
4.2.
Scientific Rationale for Study Design ..........................................................19
4.3.
Justification for Dose ..................................................................................20
4.4.
End of Study Definition ...............................................................................21
5.
STUDY POPULATION...........................................................................................21
5.1.
Inclusion Criteria.........................................................................................21
5.2.
Exclusion Criteria........................................................................................22
5.3.
Lifestyle Considerations..............................................................................24
5.3.1.
Meals and Dietary Restrictions ....................................................24
5.3.2.
Caffeine, Alcohol, and Tobacco ...................................................25
5.3.3.
Activity .........................................................................................25
5.4.
Screen Failures...........................................................................................25
6.
STUDY INTERVENTION........................................................................................25
6.1.
Study Intervention(s) Administered .............................................................26
6.2.
Preparation/Handling/Storage/Accountability..............................................26
6.3.
Measures to Minimize Bias: Randomization and Blinding ...........................26
6.4.
Study Intervention Compliance ...................................................................27
6.5.
Concomitant Therapy..................................................................................27
6.6.
Dose Modification .......................................................................................27
6.7.
Intervention after the End of the Study........................................................27
7.
DISCONTINUATION OF STUDY INTERVENTION AND PARTICIPANT 
DISCONTINUATION/WITHDRAWAL.....................................................................27
7.1.
Discontinuation of Study Intervention..........................................................27
 
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7.1.1.
Liver Chemistry Stopping Criteria ................................................28
7.1.1.1.
Study Intervention Restart or Rechallenge After 
Liver Stopping Criteria Met .........................................28
7.1.2.
QTc Stopping Criteria ..................................................................28
7.1.3.
Columbia-Suicide Severity Rating Scale Criteria..........................28
7.1.4.
Individual Participant Laboratory Abnormality and Adverse 
Event Stopping Criteria................................................................29
7.2.
Participant Discontinuation/Withdrawal from the Study ...............................29
7.3.
Lost to Follow Up........................................................................................29
8.
STUDY ASSESSMENTS AND PROCEDURES .....................................................30
8.1.
Efficacy Assessments.................................................................................30
8.2.
Safety Assessments ...................................................................................31
8.2.1.
Physical Examinations.................................................................31
8.2.2.
Vital Signs....................................................................................31
8.2.3.
Electrocardiograms......................................................................31
8.2.4.
Clinical Safety Laboratory Assessments ......................................32
8.2.5.
Suicidal Risk Monitoring and Management of Emergent 
Psychiatric Symptoms..................................................................32
8.2.6.
Gastrointestinal Toxicity Evaluation and Monitoring Plan.............33
8.3.
Adverse Events and Serious Adverse Events.............................................35
8.3.1.
Time Period and Frequency for Collecting AE and SAE 
Information...................................................................................35
8.3.2.
Method of Detecting AEs and SAEs.............................................35
8.3.3.
Follow-up of AEs and SAEs.........................................................36
8.3.4.
Regulatory Reporting Requirements for SAEs .............................36
8.3.5.
Pregnancy ...................................................................................36
8.4.
Treatment of Overdose...............................................................................36
8.5.
Pharmacokinetics .......................................................................................37
8.6.
Pharmacodynamics ....................................................................................37
8.7.
Genetics .....................................................................................................37
8.8.
Biomarkers .................................................................................................38
8.9.
Medical Resource Utilization and Health Economics ..................................38
9.
STATISTICAL CONSIDERATIONS........................................................................38
9.1.
Statistical Hypotheses.................................................................................38
9.2.
Sample Size Determination ........................................................................38
9.2.1.
Sample Size Assumptions ...........................................................38
9.2.2.
Sample Size Sensitivity................................................................39
9.3.
Populations for Analyses ............................................................................40
9.4.
Statistical Analyses.....................................................................................40
9.4.1.
Pharmacokinetic Analyses...........................................................40
9.4.2.
Safety Analyses...........................................................................42
9.4.3.
Other Analyses ............................................................................42
9.5.
Interim Analyses .........................................................................................42
9.5.1.
Data Monitoring Committee (DMC)..............................................42
10. SUPPORTING DOCUMENTATION AND OPERATIONAL 
CONSIDERATIONS...............................................................................................43
10.1.
Appendix 1: Abbreviations and Trademarks................................................43
10.2.
Appendix 2: Clinical Laboratory Tests.........................................................46
 
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10.3.
Appendix 3: Contraceptive Guidance and Collection of Pregnancy 
Information..................................................................................................48
10.3.1.
Definitions:...................................................................................48
10.4.
Appendix 4: Regulatory, Ethical, and Study Oversight 
Considerations............................................................................................49
10.4.1.
Regulatory and Ethical Considerations ........................................49
10.4.2.
Financial Disclosure.....................................................................49
10.4.3.
Informed Consent Process ..........................................................49
10.4.4.
Data Protection............................................................................50
10.4.5.
Publication Policy.........................................................................50
10.4.6.
Dissemination of Clinical Study Data ...........................................51
10.4.7.
Data Quality Assurance ...............................................................51
10.4.8.
Source Documents ......................................................................52
10.4.9.
Study and Site Closure ................................................................52
10.4.10. Publication Policy.........................................................................52
10.5.
Appendix 5: Liver Safety: Required Actions and Follow-up 
Assessments ..............................................................................................54
10.6.
Appendix 6: Adverse Events: Definitions and Procedures for 
Recording, Evaluating, Follow-up, and Reporting .......................................56
10.6.1.
Definition of AE............................................................................56
10.6.2.
Definition of SAE..........................................................................57
10.6.3.
Recording and Follow-Up of AE and SAE....................................58
10.6.4.
Reporting of SAE to VH/GSK.......................................................60
10.7.
Appendix 7: Genetics..................................................................................61
11. REFERENCES.......................................................................................................62
 
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1.
PROTOCOL SUMMARY
1.1.
Synopsis
Protocol Title: An Open-Label One-way Interaction Clinical Trial to Evaluate the 
Pharmacokinetic Interactions Between GSK3640254 and Tenofovir 
Alafenamide/Emtricitabine in Healthy Subjects
Short Title: Study to Evaluate the Effect of GSK3640254 on the PK of Tenofovir 
Alafenamide/Emtricitabine
Rationale: This is an open-label, single-sequence, one-way drug interaction study to 
investigate the effect of GSK3640254 on the pharmacokinetics (PK) of tenofovir
alafenamide (TAF) and emtricitabine (FTC). Treatment of human immunodeficiency 
virus (HIV) infection frequently involves combination therapy. It is important to 
understand any interactions and resulting changes in exposure (if any) when HIV 
medications are given in combination. Data from this study will contribute to dosing 
recommendations when GSK3640254 and TAF/FTC are given in combination.
Objectives and Endpoints:
Objective
Endpoint
Primary

To assess the effect of GSK3640254 on the 
PK of TAF, FTC, and the active metabolite 
of TAF prodrug, TFV under fed conditions in 
healthy participants

AUC(0-) and Cmax for TAF

AUC(0-), Cmax, and Cfor FTC and TFV
Secondary

To assess the safety and tolerability of 
TAF/FTC administered alone and when 
coadministered with GSK3640254 in 
healthy participants

To characterize the steady-state PK of 
GSK3640254 in the presence of TAF/FTC 
in healthy participants

To characterize the steady-state PK of TAF, 
FTC, and TFV alone and in combination 
with GSK3640254 in healthy participants

Safety and tolerability parameters for 
AEs/SAEs, observed and change from 
baseline clinical laboratory assessments, 
ECGs, and vital sign measurements

AUC(0-), Cmax, C, and Tmax for 
GSK3640254

Tmax for TAF, FTC, and TFV
AE = adverse event; AUC (0-) = area under the plasma concentration-time curve from time 0 to the end of the dosing 
interval at steady state; Cmax = maximum observed concentration; C= Plasma concentration at the end of the 
dosing interval; ECG = electrocardiogram; FTC = emtricitabine; PK = pharmacokinetics; SAE = serious adverse event; 
TAF = tenofovir alafenamide; TFV = tenofovir; Tmax = time of maximum observed concentration.
 
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Overall Design: This is a Phase 1, open-label, fixed-sequence 2-period, one-way drug 
interaction study designed to assess the pharmacokinetics (PK), safety, and tolerability of 
GSK3640254 and TAF/FTC when administered alone and in combination in healthy 
participants.
The study will consist of a screening period and 2 sequential treatment periods. 
Participants will be screened with 28 days before the first dose of study intervention. 
There is no washout between the last dose of study intervention in Period 1 and initiation 
of study intervention in Period 2. The participants will fast overnight for at least 8 hours
prior to dosing and will receive the moderate fat meal 30 minutes prior to dosing. 
Participants will eat this meal in 30 minutes or less. Dose administration will occur 
within 5 minutes of completion of meal consumption.
Pharmacokinetic blood samples for analysis of TAF, FTC, and TFV will be collected 
before dosing (0 hour) on Days 2 through 14 (Period 1) and Days 1 through 7 (Period 2) 
and up to 24 hours after TAF/FTC dosing on Period 1, Day 14 and Period 2, Day 7.
Pharmacokinetic blood samples for analysis of GSK3640254 will be collected before 
dosing (0 hour) on Days 2 through 7 (Period 2) and up to 24 hours after GSK3640254 
dosing on Day 7.
Safety and tolerability will be assessed by monitoring and recording of adverse events,
clinical laboratory test results, vital sign measurements, 12-lead electrocardiogram 
results, and physical examination findings.
Study assessments will be performed as indicated in the Schedule of Activities. 
Participants will be confined to the clinic from Day –1 until discharge on Period 2, Day 
10.
Disclosure Statement: This is a single group, single arm study that has no masking.
Number of Participants: Approximately 16 participants will be treated to ensure that 
12 evaluable participants complete the study.
Intervention Groups and Duration: The treatments will be as follows:

Treatment A: TAF/FTC 25/200 mg once daily (QD) on Days 1 through 14
(Period 1)

Treatment B: TAF/FTC 25/200 mg QD coadministered with GSK3640254 
200 mg QD on Days 1 through 7 (Period 2)
The duration of the study, including Screening, is approximately 52 days.
Data Monitoring Committee: No
1.2.
Schema
A summary of the overall study design is presented in Figure 1.
 
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Figure 1
Study Design Schematic
1.3.
Schedule of Activities (SoA)

Screening procedures may be done over more than 1 visit but must all be 
completed within 28 days prior to the first dose of study intervention.

The following demographic parameters will be captured: year of birth, sex, race, 
and ethnicity.

Medical/medication/family history will be assessed as related to the 
inclusion/exclusion criteria.
Screening Visit
Procedure
Screening (up to 28 days before Day 1)
Outpatient visit
X
Informed consent
X
Inclusion and exclusion criteria
X
Demography
X
Full physical examination including height and weight 1
X
Laboratory assessments (hematology, chemistry, urinalysis)
X
12-lead electrocardiogram (ECG)
X
Vital sign measurements
X
Medication/drug/alcohol history
X
Past and current medical conditions  
X
Columbia-Suicide Severity Rating Scale (C-SSRS)
X
Serum pregnancy test
X
Follicle-stimulating hormone (FSH) (as needed, to confirm 
postmenopausal status)
X
Drug, alcohol, and cotinine screen
X
HIV, Hepatitis B and C screening
X
HIV = human immunodeficiency virus.
1
A full physical examination will include at a minimum, assessments of the skin, cardiovascular (CV), respiratory, 
gastrointestinal (GI), and neurological systems.
 
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Time and Events Table
Procedure
Period 1
Period 2
Follow-up
Notes
Day 
–1
Day
1-5
Day 
6-13
Day 
14
Day 1
Day 2
Day 3
Day 4
Day 5
Day 6
Day 7
Day 8
Day 91
Day 10
Admit to clinic
X
Discharge from clinic
X
Brief physical examination
X
X
A brief physical 
examination will include, 
at a minimum, 
assessments of the skin, 
lungs, cardiovascular 
system, and abdomen 
(liver and spleen).
Vital sign measurements
X
X
D7
X
X
X
X
X
Single 12-lead ECG
X
D1
X
X
X
X
All ECGs in Period 1
and 2 will be pre-dose, 
post-dose at 2 hours, 
and post-dose 4 hours.
The predose ECGs on 
Day 1 of both Period 1
and Period 2 will be 
taken in triplicate.
Drug, alcohol, and 
cotinine screen
X
See Appendix 2 for 
specific tests to be 
performed.
Laboratory assessments 
(hematology, chemistry, 
urinalysis)
X
D7
X
X
X
X
See Appendix 2 for 
specific tests to be 
performed.
Pregnancy test 
X
X
Columbia-Suicide Severity 
Rating Scale 
X
X
 
 
 
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Procedure
Period 1
Period 2
Follow-up
Notes
Day 
–1
Day
1-5
Day 
6-13
Day 
14
Day 1
Day 2
Day 3
Day 4
Day 5
Day 6
Day 7
Day 8
Day 91
Day 10
Genetic sample (Optional)
X
Study intervention: 
TAF/FTC 25/200 mg
X
X
X
X
X
X
X
X
X
X
Study intervention: 
GSK3640254 200 mg
X
X
X
X
X
X
X
TAF, FTC, and TFV serial 
PK sampling
X
X
X
X
Blood collection for PK 
analysis of TAF, FTC,
and TFV will be 
collected at 0.25, 0.5, 
0.75, 1, 1.5, 2, 3, 4, 5, 6, 
8, 12, and 24 hours 
postdose (Period 1, 
Day 14 and Period 2, 
Day 7).
TAF, FTC, and TFV 
trough PK sampling 
D2-5
X
X
X
X
X
X
X
X
X
Blood collection for TAF, 
FTC, and TFV trough 
PK samples will be 
collected on Period 1, 
Days 2 through 14 and 
Period 2, Days 1
through 7.
GSK3640254 serial PK 
sampling
X
X
Blood collection for PK 
analysis of 
GSK3640254 will be 
collected at 1, 2, 2.5, 3, 
3.5, 4, 4.5, 5, 6, 8, 12, 
and 24 hours postdose
(Period 2, Day 7).
 
 
 
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Procedure
Period 1
Period 2
Follow-up
Notes
Day 
–1
Day
1-5
Day 
6-13
Day 
14
Day 1
Day 2
Day 3
Day 4
Day 5
Day 6
Day 7
Day 8
Day 91
Day 10
GSK3640254 trough PK 
sampling
X
X
X
X
X
X
Blood collection for 
GSK3640254 trough PK 
samples will be 
collected on Period 2, 
Days 2 through 7.
AE review
===============================================================================
SAE review
======================================================================================
Concomitant medication 
review
======================================================================================
AE = adverse event; D = Day; ECG = electrocardiogram; FTC = emtricitabine; PK = pharmacokinetic; SAE = serious adverse event; TAF = tenofovir alafenamide; TFV = tenofovir; W = 
washout.
1
Evaluations scheduled for Period 2, Day 9 will also be performed for participants who discontinue early.

The timing and number of planned study assessments, including safety, PK, or other assessments may be altered during the 
course of the study based on newly available data (e.g., to obtain data closer to the time of peak plasma concentrations) to ensure 
appropriate monitoring. 

Any changes in the timing or addition of time points for any planned study assessments as the result of emerging PK data from
this study must be documented and approved by the relevant study team member and then archived in the sponsor and site study 
files, but will not constitute a protocol amendment. The Institutional Review Board (IRB)/Independent Ethics Committee (IEC) 
will be informed of any safety issues that constitute a substantial amendment and require alteration of the safety monitoring 
scheme or amendment of the informed consent form (ICF). The changes will be approved by the competent authorities (CA) and 
the ethics committee (EC) before implementation.
 
 
 
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2.
INTRODUCTION
2.1.
Study Rationale
This is an open-label, single-sequence, one-way drug interaction study to investigate the 
effect of GSK3640254 on the pharmacokinetics of tenofovir alafenamide/emtricitabine
(TAF/FTC). Treatment of human immunodeficiency virus (HIV) infection frequently 
involves combination therapy. It is important to understand any interactions and resulting 
changes in exposure (if any) when HIV medications are given in combination. Data from 
this study will contribute to dosing recommendations when GSK3640254 and TAF/FTC
are given in combination.
2.2.
Background
GSK3640254 is an HIV maturation inhibitor (MI) which is improved over prior 
developmental MIs in the following ways: (1) it exhibits significantly improved 
pan-genotypic coverage and potency against polymorphic variants; (2) in vitro data 
suggest that GSK3640254 exhibits a higher barrier to emergence of resistant viruses 
(except for A364V); (3) GSK3640254 has improved potency in vitro toward all HIV-1 
subtypes; (4) it has potential for improved gastrointestinal (GI) tolerability; and (5) it has 
a projected lower once-daily human dose. Summaries of the pre-clinical and clinical 
studies are included in the Clinical Investigator's Brochure (CIB) [GSK Document 
Number 2018N379610_00].
2.2.1.
Background and Key Safety Data with a Prior Maturation Inhibitor
Bristol-Myers Squibb (BMS), and later ViiV Healthcare (VH), developed a structurally 
similar HIV-1 MI (BMS-955176/GSK3532795), which was studied through Phase 2b 
studies in both treatment-naïve (AI468038/205891) and experienced (AI468048/205892) 
HIV-1 infected adults. In study AI468038/205891, a greater number of participants who 
received GSK3532795 experienced GI intolerability (most frequently Grade 1 to 2 
diarrhea and abdominal pain). A detailed examination of all GI adverse events (AEs) 
(regardless of grade/relationship) revealed a relationship with dose [GSK Document 
Number 2016N302783_00]. Ultimately, the rate of GI intolerability in the GSK3532795 
dose groups in the Phase 2b study 205891 led in part to VH’s decision to end all trials 
and not progress to Phase 3 studies. Gastrointestinal AEs were also previously observed 
in healthy participants in Phase 1 studies with varying doses, durations, and formulations 
of GSK3532795. In both studies, the most common GI AEs were abdominal pain and 
diarrhea.
Aside from mild to moderate GI intolerability, 2 serious AEs (SAEs) occurred in the 
Phase I thorough QT study AI468044/206220 [BMS Document Number 930109388] at 
supra-therapeutic doses: 1 healthy participant had an episode of acute psychosis and
another had suicidal ideation/homicidal ideation as diagnosed through an interview by a 
psychiatrist. The 2 participants received GSK3532795 240 mg twice daily and 240 mg 
once daily (QD) with food, respectively. These events were assessed as related to study 
drug, but were not observed in any other clinical study with GSK3532795. The most 
 
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frequent neuropsychiatric AEs in studies with GSK3532795 were headache, dizziness, 
and sleep abnormalities (e.g., insomnia, abnormal dreams).
2.2.2.
Preliminary Safety and Pharmacokinetic Data in Study 207187
The primary objective of the first time in human (FTIH) clinical trial (207187) was to 
investigate the safety and tolerability of GSK3640254 following single and repeated daily 
administration. A total of 78 healthy men were ultimately randomized: 20 in the 
single-ascending dose (SAD, doses ranging from 1 to 700 mg) and 58 in the 
multiple-ascending dose (MAD, 50 to 320 mg QD for 14 days). A comprehensive 
summary of results is described in the CIB [GSK Document Number 2018N379610_00] 
and the Study Synopsis [GSK Document Number 2018N375461_00]. A concise 
summary of the data is presented below.
No deaths or SAEs were reported. There were 4 AEs leading to discontinuation. Only 1 
of these AEs was related to study medication. A subject who received GSK3640254 
200 mg QD developed a maculopapular rash after 8 days of study medication. The rash 
lasted for 6 days and there were no laboratory abnormalities. A dermatology consultant 
concluded this was a drug rash and the subject later received fexofenadine 180 mg QD/a 
topical steroid cream with resolution. The other 3 AEs occurred in SAD portion of the 
study (depression in a subject who received placebo and 2 subjects with viral infection). 
There were 9 subjects with 12 AEs assessed as related to study medication by the 
principal investigator (11 Grade 1; 1 Grade 2). The most clinically notable was a subject 
who developed elevated transaminases while receiving GSK3640254 50 mg QD for 
14 days. Specifically, there was a progressive rise in alanine aminotransferase (ALT) 
during treatment with a peak ALT of 83 IU/L on Day 16. The remaining liver chemistries 
were normal throughout. An ultrasound showed a subcapsular area of heterogenous 
echogenicity within segment 7, measuring approximately 35 × 23 × 36 mm. Follow-up 
magnetic resonance imaging and liver chemistries were normal. This subject also had 
3 unrelated AEs during the course of an isolated increased ALT: musculoskeletal 
stiffness, contact dermatitis, and headache. All other related AEs are described in the 
CIB) [GSK Document Number 2018N379610_00] and the Study Synopsis [GSK 
Document Number 2018N375461_00].
In the SAD portion of the study, 17 subjects experienced 60 individual AEs (58 Grade 1; 
2 Grade 2). The 2 Grade 2 AEs were headache and depression (both unrelated). The most 
frequent AEs were headache (6 subjects), contact dermatitis primarily due to 
electrocardiogram (ECG) electrodes (5 subjects), and diarrhea (4 subjects). There was no 
dose/AE relationship. 
In the MAD portion of the study, 43 subjects experienced 126 individual AEs 
(123 Grade 1; 3 Grade 2). The 3 Grade 2 AEs were headache (1 related and 1 unrelated) 
and back pain (unrelated). The most frequent AEs were headache (15 subjects), contact 
dermatitis (8 subjects), dizziness (7 subjects), contusion (6 subjects), fatigue (6 subjects), 
and back pain (4 subjects).
There were no clinically significant abnormal fluctuations or trends in vital signs in the 
SAD or MAD cohorts. There were no abnormal clinically significant arrhythmias or QT 
 
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prolongations (values >500 msec or increases >60 msec from Baseline) observed for any 
participant in the SAD or MAD. There were no laboratory abnormality trends across 
doses that were clinically significant or associated with any symptoms.
Preliminary GSK3640254 PK parameters derived based on nominal sampling times 
following single doses of 1 to 700 mg administered after a moderate calorie and fat 
breakfast showed GSK3640254 was slowly absorbed with a median time of maximum 
observed concentration (Tmax) observed between 3 to 4.5 hours after dosing with a 
moderate fat breakfast and slowly eliminated with a mean half-life ranging from 22 to 
26 hours. In general, exposure (maximum observed concentration [Cmax] and area under 
the plasma concentration-time curve [AUC]) increased in a close-to-dose-proportional 
manner from 1 to 400 mg with no further increase in exposure at 700 mg. 
Repeat dose preliminary PK parameters following administration of GSK3640254 50 to 
320 mg QD for 14 days were determined on Day 1 and Day 14 and showed a median 
Tmax ranging between 3.8 to 4.3 hours. The mean half-life ranged from approximately 
22 to 29 hours. Overall, there was a trend of a slightly less than dose-proportional 
increase in Cmax and AUC from time 0 to 24 hours after dosing (AUC[0-24]) from 50 to 
320 mg. The exposure on Day 14 was, on average, 1.9- to 2.3-fold higher than that of 
Day 1 for Cmax and 2.2- to 2.6-fold higher than Day 1 for AUC(0-24). Detailed 
summary statistics are available in the Study Synopsis [GSK Document 
Number 2018N375461_00].
2.2.3.
Preliminary Safety and Pharmacokinetic Data in Study 208131
The FTIH Study 207187 used a bis-hydrochloride salt capsule formulation of 
GSK3640254, which is not suitable for long term clinical development. 
Study 208131 was a single-center, open-label, 2-period, 2-sequence crossover design, 
conducted in 14 healthy subjects in the United Kingdom. This study was designed to 
assess the relative bioavailability of the formulation planned for Phase 2a (mesylate salt 
in a capsule) to the FTIH formulation (bis-hydrochloride salt in a capsule) administered 
following a moderate calorie and fat meal. All subjects completed dosing and the blinded 
preliminary safety data showed a total of 11 AEs (all Grade 1). Two AEs of headache 
were related to study drug. The most common AE was headache (3 instances). There 
were 3 GI AEs (abdominal pain, bleeding gums, and flatulence). There were no cardiac 
or psychiatric AEs. There were no clinically significant changes in vital signs, ECG 
parameters, or safety laboratory parameters.
Preliminary PK results from Study 208131 showed that in the presence of a moderate fat 
meal, the relative bioavailability of GSK3640254 following 200 mg GSK3640254 
mesylate salt administration relative to 200 mg GSK3640254 bis-hydrochloride salt 
administration was 110% and 116% based AUC from time zero extrapolated to infinity 
(AUC[0-]) and Cmax, respectively.
2.2.4.
Tenofovir Alafenamide/Emtricitabine
Descovy (tenofovir alafenamide/emtricitabine) was first approved in the United States 
(US) in 2015 [DESCOVY US Prescribing Information, 2017]. Tenofovir 
 
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alafenamide/emtricitabine are both HIV nucleoside analog reverse transcriptase 
inhibitors. Tenofovir alafenamide and emtricitabine are rapidly and extensively absorbed 
following oral administration with peak plasma concentrations occurring at 1 to 3 hours 
after dose.
Tenofovir alafenamide has a 0.51-hour median plasma half-life with a mean plasma 
Cmax and AUC from time 0 to the end of the dosing interval at steady state (AUC[0-τ])
of 0.16 µg/mL and 0.21 µg*h/mL, respectively, after repeat dosing under fed conditions. 
The pharmacologically active metabolite of the TAF prodrug is tenofovir (TFV), which 
has a mean plasma Cmax and AUC(0-τ) of 0.02 µg/mL and 0.29 µg*h/mL, respectively, 
after repeat dosing under fed conditions. Emtricitabine has a 10-hour median plasma 
half-life with a mean plasma Cmax and AUC(0-τ) of 2.1 µg/mL and 11.7 µg*h/mL, 
respectively, after repeat dosing under fed conditions. Both FTC and TFV are 
subsequently phosphorylated intracellularly, resulting in very long (approximately 2 to 
6 days) intracellular half-lives. In addition, TAF/FTC lacks many of the associated drug 
interactions, specifically with oral contraceptives, statins, antidepressants, anxiolytics, 
anticoagulants, and other medications commonly taken by HIV-positive patients. For 
more details, please reference the current Descovy label [DESCOVY US Prescribing 
Information, 2017].
2.3.
Benefit/Risk Assessment
Based upon preclinical and clinical studies, the major risks for GSK3640254 are GI 
intolerability (e.g., abdominal pain and diarrhea), prolongation of the corrected QT 
interval (QTc), and neuropsychiatric safety. Reproduction of preclinical GI toxicity 
findings (e.g., single-cell parietal cell necrosis) would be unlikely during the limited 
dosing of GSK3640254 in this study. One preclinical study showed 1 dog with an 
increased QTc interval when given a single dose of GSK3640254, although preliminary 
results from Study 207187 did not demonstrate any abnormal clinically significant 
arrhythmias or QTc prolongations (values >500 msec or increases >60 msec from 
Baseline). Finally, the protocol will exclude potential participants with any pre-existing 
significant psychiatric condition or positive (abnormal) response confirmed by the 
investigator on a clinician (or qualified designee) administered Columbia-Suicide 
Severity Rating Scale (C-SSRS). The C-SSRS assessment will also be administered by a 
clinician (or qualified designee) during the on-treatment portion of the study.
To ensure the overall safety of participants (including, but not limited to, the risk of GI 
intolerability, QTc prolongation, and neuropsychiatric safety), this clinical study will 
include healthy adults who will receive clinical, ECG, and laboratory evaluations during 
their participation.
Tenofovir alafenamide/emtricitabine was approved in the US in 2015. The risks are 
outlined in the USPI [DESCOVY US Prescribing Information, 2017].
More detailed information about the known and expected benefits and risks and 
reasonably expected AEs of GSK3640254 may be found in the CIB [GSK Document 
Number 2018N379610_00].
 
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2.3.1.
Risk Assessment
Potential Risk of Clinical Significance
Summary of Data/Rationale for Risk
Mitigation Strategy
Investigational Product (IP) GSK3640254
Cardiovascular (QT prolongation) 
Preclinically, GSK3640254 inhibited cardiac hERG/IKr 
potassium, cardiac SCN5A sodium and L-type 
calcium channel currents recorded from HEK 293 
cells stably transfected with complementary DNA 
(cDNA) from the ion channels. In a single-dose safety 
pharmacology study in telemeterized dogs, increases 
in QT interval (up to 20 ms) occurred primarily in 1 
dog given 17 mg/kg. Later, there were no 
GSK3640254-related effects on electrocardiogram 
(ECG) parameters in dogs given up to 25 mg/kg/day 
for 4 weeks.
In the FTIH Study 208187, no participants exhibited 
QTc change from baseline >60 msec or QTc 
>500 msec.
Screening: Protocol exclusion criteria based on 
screening ECG parameters and cardiac medical 
history.
On-Treatment: Participants will have ECG 
monitoring (at a clinically reasonable frequency) 
during the course of the study (see SoA, 
Section 1.3) with QTc stopping criteria (see 
Section 7.1.2).
Gastrointestinal (GI) intolerability and 
toxicity
Clinical signs indicative of GI intolerability (sporadic 
vomiting and abnormal feces beginning on Day 1 and 
continuing throughout the dosing periods) occurred 
mainly in dogs at 1 mg/kg/day. Additionally, toxicity 
findings of single-cell necrosis of parietal cells and/or 
chief cells were present in preclinical species. These 
findings were reversible. Finally, GI intolerability 
(predominately abdominal pain and diarrhea) was 
seen with a structurally related compound 
GSK3532795 which was evaluated through Phase 2b 
dosing. 
Screening: Protocol exclusion criterion based on 
pre-existing GI pathology or baseline GI 
signs/symptoms.
On-Treatment: Participants will undergo 
continuous evaluation for AEs during their 
participation in the study; there will be individual 
clinical stopping criteria based upon intensity of 
treatment-emergent AEs. A GI toxicity evaluation 
and monitoring plan will be available to guide 
investigators should GI AEs emerge (See 
Section 8.2).
 
 
 
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Potential Risk of Clinical Significance
Summary of Data/Rationale for Risk
Mitigation Strategy
Neurologic/psychiatric safety
Two psychiatric serious adverse events in previous 
maturation inhibitor GSK3532795 clinical program 
(acute psychosis, homicidal/suicidal ideation) were 
seen at supratherapeutic doses in healthy subjects in 
the thorough QT (TQT) study.
From a neurologic and psychiatric AE summary and 
pharmacokinetic/pharmacodynamic analysis for 
GSK3532795 across all studies mild Grade 1 
headache and Grade 1 sleep abnormalities were the 
predominant AEs, with a trend for increasing 
neurologic and psychiatric AEs with increasing dose 
(based on TQT and Phase 2b studies). No 
exposure-response relationship was seen for select 
neurologic and psychiatric AEs (based on TQT and 
Phase 2b studies). Central nervous system 
penetration data for GSK3532795 and GSK3640254 
in rats demonstrate a similarly low brain 
distribution/penetration.
Screening: Protocol exclusion criterion based on 
any pre-existing psychiatric condition (including 
results of psychological assessment) for 
participants. Participants will have a clinician (or 
qualified designee) administered 
Columbia-Suicide Severity Rating Scale
(C-SSRS) and will be included given no positive 
(abnormal) response.
On-Treatment: Participants will undergo 
physical examinations and laboratory testing. In 
addition, participants will undergo continuous 
evaluation for AEs during their participation in the 
study; there are individual clinical stopping 
criteria based upon incidence and intensity of 
treatment-emergent AEs. 
Participants will be housed throughout study 
conduct to ensure rapid diagnosis and 
management of any potential event.
The C-SSRS will be administered during and 
after the treatment phase of the study. In the 
event of a positive (abnormal) response 
confirmed by the investigator, the participant will 
discontinue from the trial and the investigator will 
arrange for urgent specialist psychiatric 
evaluation and management. Guidance for the 
investigator on the management of emergent 
psychiatric symptoms will be available (see 
Section 8.2.5).
Finally, there are clinical stopping criteria based 
upon intensity of treatment-emergent psychiatric 
AEs (see Section 7.1.4).
 
 
 
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2.3.2.
Benefit Assessment
This is a study in healthy participants; no medical benefits will be derived by volunteers’ 
participation.
2.3.3.
Overall Benefit: Risk Conclusion
Given the preclinical profile of GSK3640254, the clinical profile of a structurally similar 
MI (GSK3532795), the clinical data gathered from Studies 207187 and 208131, and the 
planned clinical procedures and evaluations in this study, the potential risks to 
participants receiving GSK3640254 are low, evaluable, and manageable. Descovy 
(tenofovir alafenamide/emtricitabine) was first approved in the US in 2015. The risks are 
outlined in the USPI [DESCOVY US Prescribing Information, 2017]. The potential risks 
to participants receiving TAF/FTC are low, evaluable, and manageable.
3.
OBJECTIVES AND ENDPOINTS
Objective
Endpoint
Primary

To assess the effect of GSK3640254 on the 
PK of TAF, FTC, and the active metabolite 
of TAF prodrug, TFV under fed conditions in 
healthy participants

AUC(0-) and Cmax for TAF

AUC(0-), Cmax, and Cfor FTC and TFV
Secondary

To assess the safety and tolerability of 
TAF/FTC administered alone and when 
coadministered with GSK3640254 in 
healthy participants

To characterize the steady-state PK of 
GSK3640254 in the presence of TAF/FTC 
in healthy participants

To characterize the steady-state PK of TAF, 
FTC, and TFV alone and in combination 
with GSK3640254 in healthy participants

Safety and tolerability parameters for 
AEs/SAEs, observed and change from 
baseline clinical laboratory assessments, 
ECGs, and vital sign measurements

AUC(0-), Cmax, C, and Tmax for 
GSK3640254

Tmax for TAF, FTC, and TFV
AE = adverse event; AUC (0-) = area under the plasma concentration-time curve from time 0 to the end of the dosing 
interval at steady state; Cmax = maximum observed concentration; C= Plasma concentration at the end of the 
dosing interval; ECG = electrocardiogram; FTC = emtricitabine; PK = pharmacokinetics; SAE = serious adverse event; 
TAF = tenofovir alafenamide; TFV = tenofovir; Tmax = time of maximum observed concentration.
 
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4.
STUDY DESIGN
4.1.
Overall Design
This is a Phase 1, open-label, fixed-sequence 2-period, one-way drug interaction study 
designed to assess the PK, safety, and tolerability of GSK3640254 and TAF/FTC when
administered alone and in combination in healthy participants.
The study will consist of a screening period and 2 sequential treatment periods. 
Participants will be screened within 28 days before the first dose of study intervention. 
The treatments will be as follows:

Treatment A: TAF/FTC 25/200 mg QD on Days 1 through 14 (Period 1)

Treatment B: TAF/FTC 25/200 mg QD coadministered with GSK3640254 
200 mg QD on Days 1 through 7 (Period 2)
There is no washout between the last dose of study intervention (Treatment A) in 
Period 1 and initiation of study intervention (Treatment B) in Period 2. The participants 
will fast overnight for at least 8 hours prior to dosing and will receive a moderate fat meal 
30 minutes prior to dosing. Participants will eat this meal in 30 minutes or less. Dose 
administration will occur within 5 minutes of completion of meal consumption.
Pharmacokinetic blood samples for analysis of TAF, FTC, and TFV will be collected 
before dosing (0 hour) on Days 2 through 14 (Period 1) and Days 1 through 7 (Period 2) 
and up to 24 hours after TAF/FTC dosing on Period 1, Day 14 and Period 2, Day 7. 
Pharmacokinetic blood samples for analysis of GSK3640254 will be collected before 
dosing (0 hour) on Days 2 through 7 (Period 2) and up to 24 hours after GSK3640254 
dosing on Day 7.
Safety and tolerability will be assessed by monitoring and recording of AEs, clinical 
laboratory test results, vital sign measurements, 12-lead ECG results, and physical 
examination findings.
Study assessments will be performed as indicated in the Schedule of Activities (SoA) 
(Section 1.3). Participants will be confined to the clinic from Day –1 until discharge on 
Period 2, Day 10.
4.2.
Scientific Rationale for Study Design
This is an open-label, single-sequence, one-way drug interaction study to investigate the 
PK interactions between GSK3640254 and TAF/FTC. Treatment of HIV infection 
frequently involves combination therapy. It is important to understand any interactions 
and resulting changes in exposure (if any) when HIV medications are given in 
combination, and any subsequent dosing modifications recommended.
The inhibitory potential (direct and metabolism-dependent inhibition) of GSK3640254 
towards 7 major human hepatic cytochrome P450 (CYP) enzymes was evaluated in 
human liver microsomes (CIB) [GSK Document Number 2018N379610_00]. 
 
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GSK3640254 demonstrated minimal direct inhibition of all 7 CYP isoforms tested (half 
maximal inhibitory concentration [IC50] values >13.3 µM). At the maximum projected 
clinical dose of 200 mg, there is a low risk for clinically meaningful CYP-mediated drug-
drug interactions (DDIs) with substrates of CYP1A2, CYP2B6, CYP2C8, CYP2C9, 
CYP2C19, CYP2D6, and CYP3A4.
GSK3640254 did not demonstrate human pregnane X receptor or vitamin D receptor 
mediated transactivation of CYP3A. Therefore, it is unlikely that GSK3640254 would 
induce CYP3A, or other pregnane X receptor and vitamin D receptor regulated 
enzymes/transporters in humans. In addition, GSK3640254 was tested in a panel of CYP 
induction assays using inducible cryopreserved human primary hepatocytes and showed 
no induction (EC50 >5 µM) of CYP3A4, CYP2B6, and CYP1A2.
GSK3640254 is an inhibitor of organic anion-transporting polypeptide (OATP)1B3 and 
multi-drug resistance protein (MRP)2 in vitro and has a potential of generating DDIs with 
substrates of these transporters at the projected human systemic exposures. The IC50 
values of GSK3640254 against OATP1B3 and MRP2 were 0.55 and 2.2 µM, 
respectively. In addition, GSK3640254 was an inhibitor of uridine diphosphate 
glucuronosyltransferase (UGT)1A1 in vitro (IC50 = 3.9 µM) and clinical DDIs via this 
mechanism could be possible although literature reports have not revealed clinical DDIs 
with greater than 2-fold change in exposure, with a few exceptions, due to UGT1A1 
inhibition [Lin, 2002, Williams, 2004]. Clinically meaningful DDI risk due to UGT1A1 
inhibition by GSK3640254 is likely minimal. Tenofovir alafenamide (a substrate of 
p-glycoprotein, breast cancer-resistant protein, OATP1B1, and OATP1B3) and FTC are 
primarily excreted by the kidneys by a combination of glomerular filtration and active 
tubular secretion. GSK3640254 is an inhibitor of OATP1B3; however, there is a low risk 
of meaningful DDI as TAF elimination primarily occurs in urine. This study will aid in 
understanding these interactions and resulting changes in exposure (if any) when given in 
combination.
This study is designed in accordance with the US Food and Drug Administration 
Guidance for Industry, Clinical Drug Interaction Studies—Study Design, Data Analysis, 
and Clinical Implications [DHHS, 2017] to assess the PK, safety, and tolerability of 
GSK3640254 and TAF/FTC when administered alone and in combination.
4.3.
Justification for Dose
The doses of 200 mg GSK3640254 and 25/200 mg TAF/FTC were selected for this 
study. The maximum projected clinical dose of GSK3640254 is 200 mg QD. The 
apparent terminal phase half-life (t1/2) of GSK3640254 was approximately 22 hours in 
the MAD portion of Study 207187 at the 200-mg dose, and predicted time to steady state 
is approximately 5 days. Tenofovir alafenamide/emtricitabine 25/200 mg QD was 
selected for this study because it is the currently recommended dose for HIV-infected 
patients. The t1/2 of TAF is approximately 0.5 hours and the t1/2 of FTC is 
approximately 10 hours.
Dosing of GSK3640254 QD from Period 2, Days 1 to 7 should be sufficient to bring 
plasma concentrations to steady state. There is no subsequent need for a washout of 
 
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GSK3640254 since the primary remaining evaluation is for coadministered TAF/FTC
and GSK3640254 at steady state.
4.4.
End of Study Definition
A participant is considered to have completed the study if he or she has completed all 
phases of the study including the final date on which data were or are expected to be 
collected.
The end of the study is defined as the date of the last visit of the last participant in the 
study or last scheduled procedure shown in the SoA (Section 1.3) for the last participant 
in the study.
5.
STUDY POPULATION
Prospective approval of protocol deviations to recruitment and enrollment criteria, also 
known as protocol waivers or exemptions, is not permitted.
5.1.
Inclusion Criteria
Participants are eligible to be included in the study only if all the following criteria apply:
Age
1.
Participant must be 18 to 55 years of age inclusive, at the time of signing the 
informed consent.
Type of Participant and Disease Characteristics
2.
Participants who are healthy as determined by the investigator or medically qualified 
designee based on a medical evaluation including medical history, physical 
examination, laboratory tests, and cardiac monitoring (history and ECG).
Weight
3.
Body weight ≥50.0 kg (110 lbs) for men and ≥45.0 kg (99 lbs) for women and body 
mass index (BMI) within the range 18.5 to 31.0 kg/m2 (inclusive).
Sex
4.
Male or female
a. Female participants:
A female participant is eligible to participate if she is not pregnant, not breastfeeding, 
and not a woman of childbearing potential (WOCBP) as defined in Appendix 3.
Informed Consent
5.
Capable of giving signed informed consent as described in Appendix 4 which 
includes compliance with the requirements and restrictions listed in the ICF and in 
this protocol.
 
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5.2.
Exclusion Criteria
Participants are excluded from the study if any of the following criteria apply:
Medical History
1.
Current or chronic history of liver disease, or known hepatic or biliary abnormalities 
(with the exception of Gilbert’s syndrome or asymptomatic gallstones).
2.
A pre-existing condition interfering with normal GI anatomy or motility (e.g., 
gastroesophageal reflux disease, gastric ulcers, gastritis), hepatic and/or renal 
function, that could interfere with the absorption, metabolism, and/or excretion of the 
study drugs or render the subject unable to take oral study intervention.
3.
Any history of significant underlying psychiatric disorder including, but not limited 
to, schizophrenia, bipolar disorder with or without psychotic symptoms, other 
psychotic disorders, or schizotypal (personality) disorder.
4.
Any history of major depressive disorder with or without suicidal features, or anxiety 
disorders, that required medical intervention (pharmacologic or not) such as 
hospitalization or other inpatient treatment and/or chronic (>6 months) outpatient 
treatment. Participants with other conditions such as adjustment disorder or 
dysthymia that have required shorter term medical therapy (<6 months) without 
inpatient treatment and are currently well-controlled clinically or resolved may be 
considered for entry after discussion and agreement with the ViiV Medical Monitor.
5.
Any pre-existing physical or other psychiatric condition (including alcohol or drug 
abuse), which, in the opinion of the investigator (with or without psychiatric 
evaluation), could interfere with the participant’s ability to comply with the dosing 
schedule and protocol evaluations or which might compromise the safety of the
participant.
6.
Medical history of cardiac arrhythmias or cardiac disease or a family or personal 
history of long QT syndrome.
7.
History of any kidney disease or current or chronic history of impaired renal function 
as indicated by an estimated creatinine clearance <80 mL/min.
Creatinine clearance (CrCL) is estimated by either of the following methods:
a.
the Modification of Diet in Renal Disease (MDRD) equation:  
eGFR(mL/min/1.73 m2) = 175 x (SCr)-1.154 x (Age)-0.203 x 0.742 [if female] x 
1.212 [if African American]
GFR is expressed in mL/min/1.73 m2, SCr is serum creatinine expressed in 
mg/dL, and age is expressed in years.
b.
the Cockcroft-Gault equation:
CrCL(mL/min) ={((l40–age) x weight)/(72xSCr)}x 0.85 (if female)
CrCL is expressed in mL/min, age is expressed in years, weight is expressed 
in kg, and SCr is serum creatinine expressed in mg/dL
 
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Laboratory Assessments
8.
Presence of Hepatitis B surface antigen (HBsAg) at Screening or within 3 months 
prior to starting study intervention.
9.
Positive Hepatitis C antibody test result at Screening or within 3 months prior to 
starting study intervention AND positive on reflex to Hepatitis C RNA.
10. Positive HIV-1 and -2 antigen/antibody immunoassay at Screening.
11. ALT >1.5 × upper limit of normal (ULN). A single repeat of ALT is allowed within 
a single screening period to determine eligibility.
12. Bilirubin >1.5 × ULN (isolated bilirubin >1.5 × ULN is acceptable if bilirubin is 
fractionated and direct bilirubin <35%).
13. Any acute laboratory abnormality at Screening which, in the opinion of the 
investigator, should preclude participation in the study of an investigational 
compound. 
14. Any Grade 2 to 4 laboratory abnormality at Screening, with the exception of creatine 
phosphokinase (CPK) and lipid abnormalities (e.g., total cholesterol, triglycerides, 
etc), and ALT (described above), will exclude a participant from the study unless the 
investigator can provide a compelling explanation for the laboratory result(s) and has 
the assent of the sponsor. A single repeat of any laboratory abnormality is allowed 
within a single screening period to determine eligibility.
15. A positive test result for drugs of abuse (including marijuana), alcohol, or cotinine 
(indicating active current smoking) at Screening or before the first dose of study 
intervention.
Prior/Concomitant Therapy
16. Unable to refrain from the use of prescription or non-prescription drugs, including 
vitamins, herbal and dietary supplements (including St John’s wort) within 7 days (or 
14 days if the drug is a potential enzyme inducer) or 5 half-lives (whichever is 
longer) prior to the first dose of study medication and for the duration of the study.
17. Treatment with any vaccine within 30 days prior to receiving study intervention.
18. Unwillingness to abstain from excessive consumption of any food or drink 
containing grapefruit and grapefruit juice, Seville oranges, blood oranges, or 
pomelos or their fruit juices within 7 days prior to the first dose of study 
intervention(s) until the end of the study.
Prior/Concurrent Clinical Study Experience
19. Participation in another concurrent clinical study or prior clinical study (with the 
exception of imaging trials) prior to the first dosing day in the current study: 30 days, 
5 half-lives, or twice the duration of the biological effect of the study intervention 
(whichever is longer). 
20. Where participation in the study would result in donation of blood or blood products 
in excess of 500 mL within 56 days.
 
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Diagnostic Assessments
21. Any positive (abnormal) response confirmed by the investigator on a screening 
clinician- or qualified designee-administered C-SSRS.
22. Any significant arrhythmia or ECG finding (e.g., prior myocardial infarction, 
sinoatrial pauses, bundle branch block, or conduction abnormality) which, in the 
opinion of the investigator or VH/GSK Medical Monitor, will interfere with the 
safety for the individual participant.
23. Exclusion criteria for screening ECG (a single repeat is allowed for eligibility 
determination):
Males
Females
Heart rate
<45 or >100 bpm
<50 or >100 bpm
PR Interval
<120 or >200 msec
QRS duration
<70 or >110 msec
QTcF interval 
>450 msec
>470 msec
Note: A heart rate from 100 to 110 bpm can be rechecked by ECG or vital signs within 
30 minutes to verify eligibility.
Other Exclusions
24. History of regular alcohol consumption within 6 months of the study defined as: an 
average weekly intake of >14 units. One unit is equivalent to 8 g of alcohol: a 
half-pint (~240 mL) of beer, 1 glass (125 mL) of wine, or 1 (25 mL) measure of 
spirits.
25. Regular use of tobacco- or nicotine-containing products within 3 months prior to 
Screening.
26. History of sensitivity to any of the study medications, or components thereof or a 
history of drug or other allergy that, in the opinion of the investigator or medical 
monitor, contraindicates their participation.
5.3.
Lifestyle Considerations
5.3.1.
Meals and Dietary Restrictions

Refrain from excessive consumption of red wine, grapefruit and grapefruit juice, 
Seville oranges, blood oranges, or pomelos or their fruit juices within 7 days 
prior to the first dose of study intervention(s) until the end of the study.
Excessive consumption is defined as more than one glass of wine or juice or one 
fruit per day, in combination.

Unless otherwise indicated, all doses of GSK3640254 and TAF/FTC in this 
study will be administered in the fed state. The participants will fast overnight 
for at least 8 hours prior to dosing and will receive a moderate fat meal 
30 minutes prior to dosing. Participants will eat this meal in 30 minutes or less. 
Dose administration will occur within 5 minutes of completion of meal 
consumption. Participants will not receive any further food until 4 hours 
post-dose on serial PK sampling days (Period 1, Day 14 and Period 2, Day 7). 
 
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The moderate fat meal will contain about 600 calories with approximately 30% 
of them coming from fat.

No water is allowed from 2 hours prior to dosing until 2 hours after dosing 
except for the glass of water needed to administer the study intervention (e.g.,
240 mL). Water is allowed ad libitum at all other times.

A standard lunch will be provided 4 hours after dosing. A standard dinner will 
be served approximately 10 hours after dosing. The food content of meals must 
be identical on serial PK sampling days.
5.3.2.
Caffeine, Alcohol, and Tobacco

Participants will abstain from ingesting caffeine- or xanthine-containing 
products (e.g., coffee, tea, cola drinks, and chocolate) for 24 hours before the 
start of dosing until after collection of the final PK sample.

Participants will abstain from alcohol for 48 hours before the start of dosing 
until after collection of the final PK sample. 

Use of tobacco and nicotine-containing products will not be allowed from 
3 months prior to Screening until after the final visit.

Participants must have a negative drug test at Screening and Day –1, and must 
abstain from recreational drug use from Screening until after the final visit.
5.3.3.
Activity

Participants will abstain from strenuous exercise for 24 hours before each blood 
collection for clinical laboratory tests. Participants may participate in light 
recreational activities during studies (e.g., watching television, reading).
5.4.
Screen Failures
Screen failures are defined as participants who consent to participate in the clinical study 
but are not subsequently entered in the study. A minimal set of screen failure information 
is required to ensure transparent reporting of screen failure participants to meet the 
Consolidated Standards of Reporting Trials (CONSORT) publishing requirements and to 
respond to queries from regulatory authorities. Minimal information includes 
demography, screen failure details, eligibility criteria, and any SAEs.
Individuals who do not meet the criteria for participation in this study (screen failure) 
may not be rescreened.
6.
STUDY INTERVENTION
Study intervention is defined as any investigational intervention(s), marketed product(s), 
placebo, or medical device(s) intended to be administered to a study participant according 
to the study protocol.
 
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6.1.
Study Intervention(s) Administered
Intervention Name
GSK3640254
Descovy (tenofovir 
alafenamide/emtricitabine)
Type 
drug
drug
Dose Formulation
capsule
tablet
Unit Dose 
Strength(s)
100 mg
25/200 mg
Dosage Level(s)
200 mg once daily
25/200 mg once daily
Route of 
Administration
oral
oral
IMP and NIMP
IMP
IMP
Sourcing
Provided centrally by the Sponsor 
Purchased by the Investigator
Packaging and 
Labeling
Provided in high-density 
polyethylene (HDPE) bottles. Each 
bottle will be labeled as required per 
country requirement.
Provided in HDPE bottles. Each 
bottle will be labeled as required per 
country requirement.
6.2.
Preparation/Handling/Storage/Accountability
1.
The investigator or designee must confirm appropriate temperature conditions have 
been maintained during transit for all study intervention received and any 
discrepancies are reported and resolved before use of the study intervention.
2.
Only participants enrolled in the study may receive study intervention and only 
authorized site staff may supply or administer study intervention. All study 
interventions must be stored in a secure, environmentally controlled, and monitored 
(manual or automated) area in accordance with the labeled storage conditions with 
access limited to the investigator and authorized site staff.
3.
The investigator, institution, or the head of the medical institution (where applicable) 
is responsible for study intervention accountability, reconciliation, and record 
maintenance (i.e., receipt, reconciliation, and final disposition records).
4.
Further guidance and information for the final disposition of unused study 
intervention are provided in the Study Reference Manual (SRM). 
5.
Under normal conditions of handling and administration, study intervention is not 
expected to pose significant safety risks to site staff.
6.
A Material Safety Data Sheet/equivalent document describing occupational hazards 
and recommended handling precautions either will be provided to the investigator, 
where this is required by local laws, or is available upon request from VH/GSK.
6.3.
Measures to Minimize Bias: Randomization and Blinding
This is an open-label study. All participants will receive the same treatment.
 
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6.4.
Study Intervention Compliance

When the individual dose for a participant is prepared from a bulk supply, the 
preparation of the dose will be confirmed by a second member of the study site 
staff. 

When participants are dosed at the site, they will receive study intervention 
directly from the investigator or designee, under medical supervision. The date 
and time of each dose administered in the clinic will be recorded in the source 
documents. The dose of study intervention and study participant identification 
will be confirmed at the time of dosing by a member of the study site staff other 
than the person administering the study intervention. Study site personnel will 
examine each participant’s mouth to ensure that the study intervention was 
ingested.
6.5.
Concomitant Therapy
Acetaminophen/paracetamol at doses of 2 grams/day are permitted for use any time 
during the study and their use documented in the CRF.
6.6.
Dose Modification
Not applicable.
6.7.
Intervention after the End of the Study
Participants will not receive any additional treatment from VH/GSK, or with 
GSK3640254 or TAF/FTC, after the completion of the study because only healthy 
volunteers are eligible for study participation.
7.
DISCONTINUATION OF STUDY INTERVENTION AND 
PARTICIPANT DISCONTINUATION/WITHDRAWAL
7.1.
Discontinuation of Study Intervention
In rare instances, it may be necessary for a participant to permanently discontinue study 
intervention. If study intervention is permanently discontinued, the participant will 
remain in the study to be evaluated for safety. See the SoA (Section 1.3) for data to be 
collected at the time of discontinuation of study intervention.
 
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7.1.1.
Liver Chemistry Stopping Criteria
Liver chemistry stopping and increased monitoring criteria have been designed to assure 
participant safety and evaluate liver event etiology (in alignment with the Food and Drug 
Administration premarketing clinical liver safety guidance: 
https://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guid
ances/UCM174090.pdf).
Discontinuation of study intervention for abnormal liver tests is required when a 
participant has an ALT ≥3 × ULN or if the investigator believes study intervention 
discontinuation is in the best interest of the participant. 
Details of liver safety follow-up procedures are described in Appendix 5.
7.1.1.1.
Study Intervention Restart or Rechallenge After Liver Stopping Criteria 
Met
Study intervention restart or rechallenge after liver chemistry stopping criteria are met by 
any participant in this study is not allowed.
7.1.2.
QTc Stopping Criteria
The same Fridericia QT correction formula (QTcF) must be used for each individual 
participant to determine eligibility for and discontinuation from the study. This formula 
may not be changed or substituted once the participant has been enrolled.

The Baseline QTcF should be based on averaged QTcF values of triplicate 
ECGs obtained over a brief (e.g., 5-10 minute) recording period from the Day 1 
pre-dose ECG.

A randomized participant that develops an on-treatment QTcF >500 msec or an 
increase from baseline QTcF >60 msec should have two repeat unscheduled 
ECG’s within 10 minutes. Using these triplicate ECGs, if the average QTcF
>500 msec or an increase from baseline QTcF >60 msec, the participant will be
withdrawn from the study. Finally, this participant should have repeated 
unscheduled ECGs until their QTcF measurement returns to their original 
averaged QTcF value at Day 1 pre-dose.
See the SoA (Section 1.3) for data to be collected at the time of intervention 
discontinuation and follow-up and for any further evaluations that need to be completed.
7.1.3.
Columbia-Suicide Severity Rating Scale Criteria
Emergence of any positive (abnormal) response confirmed by the investigator on a 
clinician (or qualified designee) administered C-SSRS during the on-treatment phase of 
the study will be cause for discontinuation of study intervention.
Refer to the SoA (Section 1.3) for data to be collected at the time of intervention 
discontinuation and follow-up and for any further evaluations that need to be completed.
 
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7.1.4.
Individual Participant Laboratory Abnormality and Adverse Event 
Stopping Criteria
Investigators should make every effort to have a discussion with the medical monitor 
before the next dose to help assess if the study intervention should be stopped. 

Any clinically significant AE deemed to require discontinuation of study 
intervention

Any Grade 3 or higher rash or Grade 2 rash with evidence of systemic 
involvement 

Any allergic or hypersensitivity reactions to either or both drugs

Any Grade 3 or higher psychiatric AE

New onset suicidal ideation

Any Grade 3 or higher AE related to study intervention

Any Grade 4 AE or laboratory abnormalities (with the exception of an 
asymptomatic Grade 4 cholesterol, triglyceride, or CPK increase)
7.2.
Participant Discontinuation/Withdrawal from the Study

A participant may withdraw from the study at any time at his/her own request, 
or may be withdrawn at any time at the discretion of the investigator for safety, 
behavioral, compliance, or administrative reasons. This is expected to be 
uncommon.

A subject who is withdrawn from the study for any reason related to safety 
(listed in Section 7.1.4 or otherwise) will be continued to be followed to assess 
the outcome of the safety event that triggered discontinuation of study drug.

At the time of discontinuing from the study, if possible, an early discontinuation 
visit should be conducted, as shown in the SoA. See SoA (Section 1.3) for data 
to be collected at the time of study discontinuation and follow-up and for any 
further evaluations that need to be completed.

The participant will be permanently discontinued both from the study 
intervention and from the study at that time.

If the participant withdraws consent for disclosure of future information, the 
sponsor may retain and continue to use any data collected before such a 
withdrawal of consent.

If a participant withdraws from the study, he/she may request destruction of any 
samples taken and not tested, and the investigator must document this in the site 
study records.
7.3.
Lost to Follow Up
A participant will be considered lost to follow up if he or she repeatedly fails to return for 
scheduled visits and is unable to be contacted by the study site. 
 
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The following actions must be taken if a participant fails to return to the clinic for a 
required study visit:

The site must attempt to contact the participant and reschedule the missed visit 
as soon as possible and counsel the participant on the importance of maintaining 
the assigned visit schedule and ascertain whether or not the participant wishes to 
and/or should continue in the study.

Before a participant is deemed lost to follow up, the investigator or designee 
must make every effort to regain contact with the participant (where possible, 
3 telephone calls and, if necessary, a certified letter to the participant’s last 
known mailing address or local equivalent methods). These contact attempts 
should be documented in the participant’s medical record.

Should the participant continue to be unreachable, he/she will be considered to 
have withdrawn from the study. 
Discontinuation of specific sites or of the study as a whole are handled as part of 
Appendix 4.
8.
STUDY ASSESSMENTS AND PROCEDURES

Study procedures and their timing are summarized in the SoA (Section 1.3). 

Protocol waivers or exemptions are not allowed.

Immediate safety concerns should be discussed with the sponsor immediately 
upon occurrence or awareness to determine if the participant should continue or 
discontinue study intervention.

Adherence to the study design requirements, including those specified in the 
SoA, is essential and required for study conduct.

All screening evaluations must be completed and reviewed to confirm that 
potential participants meet all eligibility criteria. The investigator will maintain 
a screening log to record details of all participants screened and to confirm 
eligibility or record reasons for screening failure, as applicable. 

Procedures conducted as part of the participant’s routine clinical management 
(e.g., blood count) and obtained before signing of ICF may be utilized for 
screening or baseline purposes provided the procedure met the 
protocol-specified criteria and was performed within the time frame defined in 
the SoA.

The maximum amount of blood collected from each participant over the 
duration of the study, including any extra assessments that may be required, will 
not exceed 500 mL.

Repeat or unscheduled samples may be taken for safety reasons or for technical 
issues with the samples.
8.1.
Efficacy Assessments
Not applicable.
 
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8.2.
Safety Assessments
Planned time points for all safety assessments are provided in the SoA (Section 1.3).
8.2.1.
Physical Examinations

A full physical examination will include, at a minimum, assessments of the skin, 
cardiovascular, respiratory, GI, and neurological systems. Height and weight 
will also be measured and recorded.

A brief physical examination will include, at a minimum, assessments of the 
skin, lungs, cardiovascular system, and abdomen (liver and spleen).

Investigators should pay special attention to clinical signs related to previous 
serious illnesses.
8.2.2.
Vital Signs

Oral temperature, pulse rate, respiratory rate, and blood pressure will be 
assessed.

Blood pressure and pulse measurements will be assessed in the semi-recumbent 
position with a completely automated device. Manual techniques will be used 
only if an automated device is not available.

Blood pressure and pulse measurements should be preceded by at least 
5 minutes of rest for the participant in a quiet setting without distractions 
(e.g., television, cell phones).

Vital signs (to be taken before blood collection for laboratory tests) will consist 
of 3 blood pressure and pulse measurements (3 consecutive blood pressure and 
pulse readings will be recorded at intervals of at least 1 minute). Each 
measurement will be recorded in the case report form (CRF).
8.2.3.
Electrocardiograms

On Period 1, Day 1 and Period 2, Day 1, triplicate ECGs will be taken prior to 
dosing. The ECGs should be recorded over a brief (e.g., 5 to 10 minutes) 
recording period. Each measurement will be recorded in the CRF.

Single 12-lead ECG will be obtained at other time points as outlined in the SoA 
(Section 1.3) using an ECG machine that automatically calculates the heart rate 
and measures PR, QRS, QT, and QTcF intervals. Refer to Section 7.1.2 for 
QTcF withdrawal criteria and additional QTcF readings that may be necessary.

Twelve-lead ECGs will be performed with the participant in a supine or 
semi-supine position after a rest of at least 10 minutes.

At each time point at which triplicate ECGs are required, 3 individual ECG 
tracings should be obtained as closely as possible in succession, but no more 
than 2 minutes apart. The full set of triplicates should be completed over a brief 
(e.g., 5 to 10 minutes) recording period.
 
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8.2.4.
Clinical Safety Laboratory Assessments

Refer to Appendix 2 for the list of clinical laboratory tests to be performed and 
to the SoA (Section 1.3) for the timing and frequency. 

The investigator must review the laboratory report, document this review, and 
record any clinically relevant changes occurring during the study in the AE 
section of the CRF. The laboratory reports must be filed with the source 
documents. Clinically significant abnormal laboratory findings are those which 
are not associated with the underlying disease, unless judged by the investigator 
to be more severe than expected for the participant's condition.

All laboratory tests with values considered clinically significantly abnormal 
during participation in the study or within 7 days after the last dose of study 
intervention should be repeated until the values return to normal or Baseline or 
are no longer considered significantly abnormal by the investigator or medical 
monitor. 

If such values do not return to normal/baseline within a period of time judged 
reasonable by the investigator, the etiology should be identified and the sponsor 
notified.

All protocol-required laboratory assessments, as defined in Appendix 2, must be 
conducted in accordance with the laboratory manual and the SoA.
8.2.5.
Suicidal Risk Monitoring and Management of Emergent 
Psychiatric Symptoms
GSK3640254 is not a central nervous system active drug nor is it being developed for a 
neurologic or psychiatric condition. However, given the risk of suicidal ideation 
identified with previous MI GSK3532795, all participants will undergo screening using 
the C-SSRS administered by a clinician (or qualified designee); any positive (abnormal) 
response confirmed by the investigator will exclude them from participating. A repeat 
assessment will be done at the end of the treatment phase of the study. In case of positive 
(abnormal) response confirmed by the investigator, the participant will discontinue from 
the trial and the investigator will arrange for urgent specialist psychiatric evaluation and 
management.
As described in Section 7.1.4, new onset suicidal ideation at any time will result in 
immediate discontinuation from the trial and the investigator will arrange for urgent 
specialist psychiatric evaluation and management.
The definitions of behavioral suicidal events used in this scale are based on those used in 
the Columbia-Suicide History Form [Posner, 2007]. Questions are asked on suicidal 
behavior, suicidal ideation, and intensity of ideation. Screening visit questions will be in 
relation to lifetime experiences and current experiences (within the past 2 months) and all 
subsequent questioning in relation to the last assessment.
Emergent non-suicidal Psychiatric AE Evaluation and Management:
 
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
Any Grade 1 or 2 psychiatric AE: A Grade 1 or 2 psychiatric AE may result in 
additional unscheduled visits (in-clinic or at home) as clinically indicated. This 
may include a more in-depth assessment of AE through interview, additional 
unscheduled clinical labs, and/or imaging. Psychiatric consultation may be 
required at the discretion of the investigator. Any pharmacotherapy should be 
discussed with the medical monitor.

Any Grade 3 or 4 psychiatric AE: As described in Section 7.1.4, a Grade 3 or 4 
psychiatric AE will result in discontinuation from the trial and emergency 
psychiatric evaluation (including potential hospitalization and pharmacotherapy 
as indicated).
8.2.6.
Gastrointestinal Toxicity Evaluation and Monitoring Plan
Preclinical toxicology studies in rats and dogs have suggested a potential for GI-related 
toxicity with GSK3640254. This section provides general guidance to the investigator on 
the evaluation and management of primarily upper GI symptoms (Table 1). The 
investigator may contact the VH/GSK Medical Monitor to discuss evaluation and 
management (including discontinuation of a participant) of any GI symptoms throughout 
the study.
Table 1
Gastrointestinal Toxicity Evaluation and Management
HISTORY
For symptoms of all grades, a thorough history forms the foundation 
of proper evaluation and management. The following are potential 
manifestations of some GI clinical syndromes that may occur 
(possibly in combination) during the clinical study. 
Nausea and Vomiting
The investigator should attempt to identify the etiology of these symptoms 
(and whether it is intraperitoneal, extraperitoneal, medication related, 
infection related, or due to a metabolic disorder [Hasler, 2012]. 
Medications can cause nausea and vomiting acutely. 
Dyspepsia
The investigator should identify the presence of red flags (odynophagia, 
unexplained weight loss, recurrent vomiting, GI bleeding, jaundice, 
palpable mass or adenopathy, or family history of GI malignancy). 
Symptoms of dyspepsia could include early satiety, bloating, or belching. 
Additionally, atypical symptoms of dyspepsia could include: pharyngitis, 
asthma, bronchitis, hoarseness, chest pain, or abdominal pain. 
Other Clinical 
Syndromes
Additional diagnostic criteria for other GI disorders potentially encountered 
in the clinical study are available elsewhere [Rome Foundation, 2018].
PHYSICAL 
EXAMINATION
Physical examination should complement elements obtained from 
the history [Hasler, 2012]. Acutely, the investigator may assess for 
signs of intravascular volume depletion (e.g., orthostasis) and/or 
aspiration of vomitus as appropriate. Abdominal tenderness and 
guarding may indicate inflammation. The presence of fecal blood 
can indicate mucosal damage (e.g., from an ulcer). Complete 
 
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evaluation of dyspepsia should include an oral examination (poor 
dentition or pharyngeal erythema) and lungs for wheezing. 
DIAGNOSTIC 
EVALUATION AND 
MANAGEMENT
A major goal in the diagnostic evaluation of a participant with upper 
GI symptoms is to quickly arrive at a final diagnosis without
exposing the participant to unnecessary (invasive) testing; 
investigators should exercise good clinical judgment in this regard 
[Soll, 2009]. A major goal of therapy is directed at correcting the 
underlying identifiable medical or surgical abnormalities. 
Consultation (e.g., gastroenterologist) is recommended as clinically 
indicated.
Grade 1 symptoms
Participants may be treated symptomatically. If participants develop 
dyspepsia alone, generally only limited and direct diagnostic testing 
should be performed. If the participant has dyspepsia they should limit 
alcohol, caffeine, chocolate, tobacco, and eating directly before bedtime. 
Grade 2 symptoms
Diagnostic testing may include but is not limited to the following (as 
clinically indicated):

Serum chemistries and assessment of hemoglobin if not recently 
performed 

Testing for Helicobacter pylori

Polymerase chain reaction for viruses (e.g., cytomegalovirus)
For participants who are infected with H. pylori, discontinuation from the 
study is necessary. Management should be targeted at addressing the 
underlying pathology.
Grade 3 symptoms 1
Diagnostic testing may include but is not limited to the following (as 
clinically indicated):

The testing outlined above in Grade 2

A barium swallow 

Computed tomography scan to identify GI inflammation 

Upper endoscopy with biopsy as indicated (e.g., mucosal injury or the 
presence of red flags)
Management should be targeted at addressing the underlying pathology.
Grade 4 symptoms 1
Diagnostic testing may include but is not limited to the following (as 
clinically indicated):

The testing outlined above in Grade 2 and Grade 3

An acute abdominal series
Initial management can include correction of hemodynamic and 
electrolyte abnormalities as clinically indicated. After stabilization, 
management should be targeted at addressing the underlying pathology.
GI = gastrointestinal.
1
A Grade 4 or related Grade 3 AE: The Investigator will discontinue the participant from the study and perform an 
evaluation/management plan incorporating elements above.
 
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8.3.
Adverse Events and Serious Adverse Events
The definitions of an AE or SAE can be found in Appendix 6. As described in 
Appendix 6, intensity of AEs (and laboratory abnormalities) will be graded using the 
most recent version of the Division of AIDS (DAIDS) grading table at the time of the last 
participant last visit. While the study population will consist of HIV-1 seronegative 
healthy volunteers, the DAIDS criteria will be used in later clinical studies (Phase 2a and 
beyond); additionally, the DAIDS criteria have a more conservative grading scale relative 
to other scales (e.g., CTCAE v 4.0). Thus, participant safety evaluation and monitoring 
will be more conservative.
The investigator and any qualified designees are responsible for detecting, documenting, 
and reporting events that meet the definition of an AE or SAE, and remain responsible for 
following up AEs that are serious, considered related to the study intervention or the 
study, or that caused the participant to discontinue the study (see Section 7).
8.3.1.
Time Period and Frequency for Collecting AE and SAE 
Information

All SAEs will be collected from the signing of the ICF until the end of the study 
at the time points specified in the SoA (Section 1.3).

All AEs will be collected from the start of intervention until the end of the study 
at the time points specified in the SoA (Section 1.3).

Medical occurrences that begin before the start of study intervention but after 
obtaining informed consent will be recorded on the Medical History/Current 
Medical Conditions section of the CRF, not the AE section.

All SAEs will be recorded and reported to the sponsor or designee immediately 
and under no circumstance should this exceed 24 hours, as indicated in 
Appendix 6. The investigator will submit any updated SAE data to the sponsor 
within 24 hours of it being available.

Investigators are not obligated to actively seek AEs or SAEs after the conclusion 
of the study participation. However, if the investigator learns of any SAE, 
including a death, at any time after a participant has been discharged from the 
study, and he/she considers the event to be reasonably related to the study 
intervention or study participation, the investigator must promptly notify the 
sponsor.
8.3.2.
Method of Detecting AEs and SAEs

The methods of recording, evaluating, and assessing causality of AEs and SAEs 
and the procedures for completing and transmitting SAE reports are provided in 
Appendix 6.

Care will be taken not to introduce bias when detecting an AE and/or SAE. 
Open-ended and non-leading verbal questioning of the participant is the
preferred method to inquire about AE occurrence.
 
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8.3.3.
Follow-up of AEs and SAEs
After the initial AE/SAE report, the investigator is required to proactively follow each 
participant at subsequent visits/contacts. All SAEs will be followed until the event is 
resolved, stabilized, otherwise explained, or the participant is lost to follow-up (as 
defined in Section 7.3). Further information on follow-up procedures is given in 
Appendix 6.
8.3.4.
Regulatory Reporting Requirements for SAEs

Prompt notification by the investigator to the sponsor of an SAE is essential so 
that legal obligations and ethical responsibilities towards the safety of 
participants and the safety of a study intervention under clinical investigation are 
met. 

The sponsor has a legal responsibility to notify both the local regulatory 
authority and other regulatory agencies about the safety of a study intervention 
under clinical investigation. The sponsor will comply with country-specific 
regulatory requirements relating to safety reporting to the regulatory authority, 
IRB/IEC, and investigators.

Investigator safety reports must be prepared for suspected unexpected serious 
adverse reactions (SUSAR) according to local regulatory requirements and 
sponsor policy and forwarded to investigators as necessary.

An investigator who receives an investigator safety report describing a SAE or 
other specific safety information (e.g., summary or listing of SAEs) from the 
sponsor will review and then file it along with the CIB and will notify the 
IRB/IEC, if appropriate according to local requirements.
8.3.5.
Pregnancy

Details of all pregnancies in female participants will be collected after the start 
of study intervention and through the end of pregnancy (termination or 
delivery).

If a pregnancy is reported, the investigator should inform VH/GSK within 
24 hours of learning of the pregnancy and should follow the procedures outlined 
in Appendix 3.

Abnormal pregnancy outcomes (e.g., spontaneous abortion, fetal death, 
stillbirth, congenital anomalies, ectopic pregnancy) are considered SAEs.
8.4.
Treatment of Overdose
For this study, any dose of GSK3640254 or TAF/FTC greater than the planned dose 
within a 24-hour time period (±2 hours) will be considered an overdose.
VH/GSK does not recommend specific treatment for an overdose. The investigator will 
use clinical judgment to treat an overdose.
 
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In the event of an overdose, the investigator should:
1.
Contact the medical monitor immediately.
2.
Closely monitor the participant for AE/SAE and laboratory abnormalities until 
GSK3640254 or TAF/FTC can no longer be detected systemically (at least 5 days).
3.
Obtain a plasma sample for PK analysis immediately and through 7 days after the 
date of the last dose of study intervention if requested by the medical monitor 
(determined on a case-by-case basis).
4.
Document the quantity of the excess dose as well as the duration of the overdosing in 
the CRF.
Decisions regarding dose interruptions or modifications will be made by the investigator 
in consultation with the medical monitor based on the clinical evaluation of the 
participant.
8.5.
Pharmacokinetics

Whole blood samples of approximately 2 mL will be collected for measurement 
of plasma concentrations of GSK3640254 as specified in the SoA (Section 1.3). 

Separate whole blood samples of approximately 4 mL will be collected for 
measurement of plasma concentrations of TAF, FTC, and TFV as specified in 
the SoA (Section 1.3). 

A maximum of 10 samples may be collected at additional time points during the 
study if warranted and agreed upon between the investigator and the sponsor. 
Instructions for the collection and handling of biological samples will be 
provided by the sponsor. The actual date and time (24-hour clock time) of each 
sample will be recorded.

Samples will be used to evaluate the PK of GSK3640254 and TAF, FTC, and 
TFV. Each plasma sample will be divided into 2 aliquots (1 each for PK and a 
back-up). Samples collected for analyses of GSK3640254 and TAF, FTC, and 
TFV plasma concentration may also be used to evaluate safety aspects related to 
concerns arising during or after the study.

Once the plasma has been analyzed for GSK3640254 and TAF, FTC, and TFV, 
any remaining plasma may be analyzed for other compound-related metabolites 
and the results reported under a separate protocol.
8.6.
Pharmacodynamics
Pharmacodynamic endpoints are not evaluated in this study.
8.7.
Genetics
A 10-mL blood sample for DNA isolation will be collected from participants who have 
consented to participate in the genetics analysis component of the study. Participation is 
optional. Participants who do not wish to participate in the genetic research may still 
participate in the study.
 
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In the event of DNA extraction failure, a replacement genetic blood sample may be 
requested from the participant. Signed informed consent will be required to obtain a 
replacement sample unless it was included in the original consent.
See Appendix 7 for information regarding genetic research. Details on processes for 
collection and shipment and destruction of these samples can be found in the SRM.
8.8.
Biomarkers
Biomarkers are not evaluated in this study.
8.9.
Medical Resource Utilization and Health Economics
Medical Resource Utilization and Health Economics parameters are not evaluated in this 
study.
9.
STATISTICAL CONSIDERATIONS
9.1.
Statistical Hypotheses
There is no formal research hypothesis that will be statistically tested in this study.
Coadministration of GSK3640254 and TAF and FTC may increase the exposure of TAF, 
FTC, and the metabolite TFV, and coadministration of GSK3640254 with TAF and FTC 
are expected to have no significant impact on the exposure of GSK3640254.
9.2.
Sample Size Determination
9.2.1.
Sample Size Assumptions
Based on the results from a previous PK study for TAF and FTC (GS-US-120-0118) the 
intra-subject coefficient of variation (CVw) was <20% for AUC(0-τ) and Cmax. 
Therefore, it is decided that 20% would be a conservative estimate on which the sample 
size calculation is based. Since it is expected that coadministration of GSK3640254 and 
TAF/FTC may increase the exposure of TAF, FTC, and the metabolite TFV, a range for 
point estimate (PE) for a ratio of 1.0, 1.1, and 1.2 were explored.
Based on the results from preliminary PK studies for GSK3640254 (GSK Study 207187 
and 208131) the CVw ranged from 17% to 38% and 13% to 31%, respectively, for AUC
(0-τ) and Cmax. Therefore, it is decided that 38% would be a conservative estimate on 
which the sample size calculation is based. Since it is expected that coadministration of 
GSK3640254 with TAF/FTC is expected to have no significant impact on the exposure 
of GSK3640254 a range for PE for a ratio of 0.9, 1.0, and 1.1 were explored.
For TAF/FTC, with a sample size of 12 evaluable subjects, it is estimated that the 
precision (i.e., half-width of the 90% confidence interval [CI] on the log and ratio scale), 
and CI on the original scale for each PE will be as follows:
Drug
CVw (%)
Half-Width 
(log scale)
Half-Width 
(original scale)
Point Estimate
90% CI
TAF/FTC
20
0.145
0.156
1.0
(0.865, 1.156)
1.1
(0.952, 1.272)
1.2
(1.038, 1.387)
 
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For GSK3640254, with a sample size of 12 evaluable subjects, it is estimated that the 
precision (i.e., half-width of the 90% CI on the log and ratio scale), and CI on the original 
scale for each PE will be as follows:
Drug
CVw (%)
Half-Width 
(log scale)
Half-Width 
(original scale)
Point Estimate
90% CI
GSK3640254
38
0.269
0.309
0.9
(0.688, 1.178)
1.0
(0.764, 1.309)
1.1
(0.841, 1.440)
9.2.2.
Sample Size Sensitivity
For a sensitivity analysis, assuming a range of within-subject variability, a sample size of 
12 evaluable subjects, it is estimated that the precision (i.e., half-width of the 90% CI on 
the log and ratio scale), and CI on the original scale for each PE will be as follows:  
Drug
CVw (%)
Half-Width 
(log scale)
Half-Width 
(original scale)
Point Estimate
90% CI
TAF/FTC or 
GSK3640254
10
0.073
0.076
0.9
(0.837, 0.968)
1.0
(0.930, 1.076)
1.1
(1.023, 1.183)
1.2
(1.116, 1.291)
20
0.145
0.156
0.9
(0.779, 1.040)
1.0
(0.865, 1.156)
1.1
(0.952, 1.272)
1.2
(1.038, 1.387)
30
0.215
0.240
0.9
(0.726, 1.116)
1.0
(0.807, 1.240)
1.1
(0.887, 1.364)
1.2
(0.968, 1.488)
40
0.283
0.327
0.9
(0.678, 1.194)
1.0
(0.754, 1.327)
1.1
(0.829, 1.460)
1.2
(0.904, 1.593)
Approximately 16 participants will be treated to ensure that 12 evaluable participants
complete the study.
 
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9.3.
Populations for Analyses
For purposes of analysis, the following populations are defined:
Population
Description
Screened
All participants who sign the ICF.
Safety
All participants who receive at least 1 dose of study medication. This 
population will be used for all demographic and safety summaries.
Pharmacokinetic 
Concentration
The PK Concentration Population will include all participants who 
undergo plasma PK sampling and have evaluable PK assay results. 
This population will be used for the concentration listing.
Pharmacokinetic Parameter
The PK Parameter Population will include all participants who 
undergo plasma PK sampling and have evaluable PK parameters 
estimated. This population will be used for PK parameter listing, 
plotting of the concentration-time data and PK parameter summary.
9.4.
Statistical Analyses
9.4.1.
Pharmacokinetic Analyses
Plasma GSK3640254 and TAF, FTC, and TFV concentration-time data will be analyzed 
by PPD, under the oversight of Clinical Pharmacology Modeling & Simulation 
department within GSK, using noncompartmental methods with Phoenix WinNonlin 
Version 6.4 or higher. Statistical analysis will be performed by PPD, under the oversight 
of Clinical Statistics, GSK. Calculations will be based on the actual sampling times 
recorded during the study.
 
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Endpoint
Statistical Analysis Methods
Primary

The primary endpoints of this study are PK-related. The analysis for the 
primary PK endpoints will be performed for the PK Parameter Population. 
Plasma concentrations of TAF, FTC, and TFV will be subjected to PK 
analyses using noncompartmental methods.

Based on the individual concentration-time data the following primary plasma 
parameters will be estimated:

TAF (Periods 1 and 2): AUC(0-) and Cmax

FTC and TFV (Periods 1 and 2): AUC(0-), Cmax, and C

Analyses will be performed to assess the effect of GSK3640254 on the PK of 
TAF, FTC, and TFV, as appropriate. Analyses will be performed on the 
natural logarithms of AUC(0-), C, and Cmax using linear mixed-effect 
models with treatment as a fixed effect and subject as a random effect. 
Effects will be estimated, and CIs will be constructed for the following 
treatment comparison:

Period 2 versus Period 1

Point estimates and 90% CIs for treatment differences on the log scale 
derived from the model will be exponentiated to obtain estimates for 
geometric mean ratios and CIs on the original scale.

Summary statistics (arithmetic mean, geometric mean, median, standard 
deviation, minimum, maximum, and coefficient of variation) for plasma TAF, 
FTC, and TFV PK parameter values will be summarized by study day.
Secondary

Plasma concentrations of GSK3640254 will be subjected to PK analyses 
using noncompartmental methods.

Based on the individual concentration-actual time data the following 
secondary plasma parameters will be estimated:

TAF, FTC, and TFV (Periods 1 and 2): Tmax 

GSK3640254 (Period 2): AUC(0-), Cmax, C, and Tmax (note: 
GSK3640254 PK parameter values in the presence of TAF/FTC from this 
study will be compared with GSK3640254 PK parameter values from
previous studies)

Summary statistics (arithmetic mean, geometric mean, median, standard 
deviation, minimum, maximum, and coefficient of variation) for plasma 
GSK3640254 and TAF, FTC, and TFV PK parameter values will be 
summarized by study day. 

Additionally, predose (trough) PK plasma concentrations (TAF, FTC, and 
TFV: Days 2 through 14 [Period 1] and 1 through 7 [Period 2]; GSK3640254: 
Days 2 through 7 [Period 2]) will be summarized using the PK Concentration 
Population, and used to assess achievement of steady state.
Exploratory
Will be described in the reporting and analysis plan
 
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9.4.2.
Safety Analyses
All safety analyses will be performed on the Safety Population. 
Safety data will be presented in tabular format and summarized descriptively according to 
GSK’s Integrated Data Standards Library (IDSL) standards. No formal statistical analysis 
of the safety data will be conducted.
The details of the statistical analyses of safety and PK data will be provided in the 
reporting and analysis plan.
9.4.3.
Other Analyses
Not applicable.
9.5.
Interim Analyses
No interim analysis is planned.
9.5.1.
Data Monitoring Committee (DMC)
Not applicable.
 
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10.
SUPPORTING DOCUMENTATION AND OPERATIONAL
CONSIDERATIONS
10.1.
Appendix 1: Abbreviations and Trademarks
AE
Adverse event
ALT
Alanine aminotransferase
AST
Aspartate aminotransferase
AUC
Area under the plasma concentration-time curve
AUC(0-)
Area under the plasma concentration-time curve from 
time zero extrapolated to infinity
AUC(0-)
Area under the plasma concentration-time curve from 
time 0 to the end of the dosing interval at steady state
AUC(0-24)
Area under the plasma concentration-time curve from 
time 0 to 24 hours after dosing
BMI
Body Mass Index
BMS
Bristol-Myers Squibb
CA
Competent Authorities
cDNA
Complementary Deoxyribonucleic acid
CFR
Code of Federal Regulations
CI
Confidence interval
CIB
Clinical Investigator's Brochure 
Cmax
Maximum observed concentration 
CONSORT
Consolidated Standards of Reporting Trials 
CPK
Creatine phosphokinase
CRF
Case report form
C-SSRS
Columbia-Suicide Severity Rating Scale
C
Plasma concentration at the end of the dosing interval
CV
Cardiovascular
CVw
Intra-subject coefficient of variation
CYP
Cytochrome P450
DAIDS
Division of AIDS
DDI
Drug-drug interaction
EC
Ethics Committee
ECG
Electrocardiogram 
FSH
Follicle-stimulating hormone
FTC
Emtricitabine
FTIH
First-time-in-human
GCP
Good Clinical Practice
 
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GI
Gastrointestinal
GSK
GlaxoSmithKline 
IC50
Half maximal inhibitory concentration
HBsAg
Hepatitis B surface antigen
HDPE
High-density Polyethylene
HIPPA
Health Insurance Portability and Accountability Act
HIV
Human immunodeficiency virus
HRT
Hormonal replacement therapy
ICF
Informed consent form 
ICH
International Council for Harmonisation
IDSL
Integrated Data Standards Library
IEC
Independent Ethics Committee 
IgM
Immunoglobulin M
INR
International normalized ratio
IRB
Institutional Review Board 
LDH
Lactate dehydrogenase
MAD
Multiple-ascending dose
µg
Micrograms
mg
Milligrams
MI
Maturation inhibitor
MRP
Multi-drug resistance protein
OATP
Organic anion-transporting polypeptide
PE
Point estimate
PK
Pharmacokinetic(s)
QD
Once daily
QTc
Corrected QT interval
QTcF
Fridericia QT correction formula
SAD
Single-ascending dose
SAE
Serious adverse event 
SoA
Schedule of activities
SRM
Study Reference Manual 
SUSAR
Suspected unexpected serious adverse reactions
t1/2
Terminal phase half-life
TAF/FTC
Tenofovir alafenamide/emtricitabine
TFV
Tenofovir
Tmax
Time of maximum observed concentration
TQT
Thorough QT
UGT
Uridine diphosphate glucuronosyltransferase
 
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ULN
Upper limit of normal 
US
United States
USPI
United States Prescribing Information
VH
ViiV Healthcare
WOCBP
Woman of childbearing potential 
Trademark Information
Trademarks of ViiV Healthcare
Trademarks not owned by the ViiV 
Healthcare
NONE
DAIDS
DESCOVY
 
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10.2.
Appendix 2: Clinical Laboratory Tests

The tests detailed in Table 2 will be performed by the local laboratory. 

Protocol-specific requirements for inclusion or exclusion of participants are 
detailed in Section 5 of the protocol.

Additional tests may be performed at any time during the study as determined 
necessary by the investigator or required by local regulations.

Pregnancy Testing
Refer to Section 5.1 Inclusion Criteria for screening pregnancy criteria.
Pregnancy testing (urine or serum as required by local regulations) should be 
conducted at the time points indicated in the SoA (Section 1.3).
Additional serum or urine pregnancy tests may be performed, as determined 
necessary by the investigator or required by local regulation, to establish the 
absence of pregnancy at any time during the participant's participation in the 
study.
Table 2
Protocol-Required Safety Laboratory Assessments
Laboratory 
Assessments
Parameters
Hematology
Platelet Count
Red Blood Cell Indices:
White blood cell count with 
differential:
Red Blood Cell Count
Mean corpuscular volume
Neutrophils
Hemoglobin
Mean corpuscular hemoglobin 
Lymphocytes
Hematocrit
Monocytes
Eosinophils
Basophils
Clinical Chemistry 1
Blood urea nitrogen
Aspartate aminotransferase
Globulin
Creatinine
Alanine aminotransferase
Anion gap
Glucose (fasting)
Gamma-glutamyl transferase
Alkaline phosphatase
Potassium
Total and direct bilirubin
Uric acid
Sodium
Lactate dehydrogenase
Creatine phosphokinase
Calcium
Total cholesterol
Serum lipase
Chloride
Triglycerides
Serum amylase
Phosphorus
Total protein
Carbon dioxide
Albumin
Routine Urinalysis

Specific gravity

pH, glucose, protein, blood, ketones, bilirubin, urobilinogen, nitrite, and leukocyte 
esterase by dipstick

Microscopic examination (if blood, leukocyte esterase, or protein is abnormal)
 
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Laboratory 
Assessments
Parameters
Other Screening 
Tests

Serology: HIV-1 and -2 antigen/antibody immunoassay, Hepatitis B surface 
antigen (HBsAg), Hepatitis C (Hep C antibody)

Alcohol, cotinine, and drug screen (to include at minimum amphetamines, 
barbiturates, cocaine, opiates, cannabinoids, and benzodiazepines)

Pregnancy 2
1.
Details of liver chemistry stopping criteria and required actions and follow-up assessments after liver stopping or 
monitoring event are given in Section 7.1 and Appendix 7. All events of ALT 3 ULN and bilirubin 2 × ULN 
(>35% direct bilirubin) or ALT 3 × ULN and international normalized ratio (INR) >1.5, if INR measured, which 
may indicate severe liver injury (possible Hy’s Law), must be reported as an SAE (excluding studies of hepatic 
impairment or cirrhosis).
2.
Local urine testing will be standard for the protocol unless serum testing is required by local regulation or IRB/IEC.
 
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10.3.
Appendix 3: Contraceptive Guidance and Collection of 
Pregnancy Information
10.3.1.
Definitions:
Woman of Childbearing Potential (WOCBP)
A woman is considered fertile following menarche and until becoming post-menopausal 
unless permanently sterile (see below).
If fertility is unclear (e.g., amenorrhea in adolescents or athletes) and a menstrual cycle 
cannot be confirmed before first dose of study intervention, additional evaluation should 
be considered.
Women in the following categories are not considered WOCBP
1.
Premenarchal
2.
Premenopausal female with 1 of the following:

Documented hysterectomy

Documented bilateral salpingectomy

Documented bilateral oophorectomy
For individuals with permanent infertility due to an alternate medical cause other than the 
above, (e.g., müllerian agenesis, androgen insensitivity), investigator discretion should be 
applied to determining study entry.
Note: Documentation can come from the site personnel’s review of the participant’s 
medical records, medical examination, or medical history interview.
3.
Postmenopausal female

A postmenopausal state is defined as no menses for 12 months without an 
alternative medical cause. 

A high follicle-stimulating hormone (FSH) level in the postmenopausal range 
may be used to confirm a postmenopausal state in women not using hormonal 
contraception or hormonal replacement therapy (HRT). However, in the 
absence of 12 months of amenorrhea, confirmation with more than 1 FSH 
measurement (>40 IU/L or mIU/mL) is required. 

Females on HRT and whose menopausal status is in doubt will be required to 
use 1 of the non-estrogen hormonal highly effective contraception methods if 
they wish to continue their HRT during the study. Otherwise, they must 
discontinue HRT to allow confirmation of postmenopausal status before 
study enrollment.
 
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10.4.
Appendix 4: Regulatory, Ethical, and Study Oversight 
Considerations
10.4.1.
Regulatory and Ethical Considerations

This study will be conducted in accordance with the protocol and with:

Consensus ethical principles derived from international guidelines 
including the Declaration of Helsinki and Council for International 
Organizations of Medical Sciences International Ethical Guidelines

Applicable International Council for Harmonisation (ICH) Good Clinical 
Practice (GCP) Guidelines

Applicable laws and regulations

The protocol, protocol amendments, ICF, CIB, and other relevant documents 
(e.g., advertisements) must be submitted to an IRB/IEC by the investigator and 
reviewed and approved by the IRB/IEC before the study is initiated. 

Any amendments to the protocol will require IRB/IEC approval before 
implementation of changes made to the study design, except for changes 
necessary to eliminate an immediate hazard to study participants. 

The investigator will be responsible for the following:

Providing written summaries of the status of the study to the IRB/IEC 
annually or more frequently in accordance with the requirements, policies, 
and procedures established by the IRB/IEC

Notifying the IRB/IEC of SAEs or other significant safety findings as 
required by IRB/IEC procedures

Providing oversight of the conduct of the study at the site and adherence to 
requirements of 21 Code of Federal Regulations (CFR), ICH guidelines, 
the IRB/IEC, European regulation 536/2014 for clinical studies (if 
applicable), and all other applicable local regulations
10.4.2.
Financial Disclosure
Investigators and sub-investigators will provide the sponsor with sufficient, accurate 
financial information as requested to allow the sponsor to submit complete and accurate 
financial certification or disclosure statements to the appropriate regulatory authorities. 
Investigators are responsible for providing information on financial interests during the 
course of the study and for 1 year after completion of the study.
10.4.3.
Informed Consent Process

The investigator or his/her representative will explain the nature of the study to 
the participant or his/her legally authorized representative and answer all 
questions regarding the study. 

Participants must be informed that their participation is voluntary. Participants 
or their legally authorized representative will be required to sign a statement of 
 
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informed consent that meets the requirements of 21 CFR 50, local regulations, 
ICH guidelines, Health Insurance Portability and Accountability Act (HIPAA) 
requirements, where applicable, and the IRB/IEC or study center. 

The medical record must include a statement that written informed consent was 
obtained before the participant was enrolled in the study and the date the written 
consent was obtained. The authorized person obtaining the informed consent 
must also sign the ICF.

Participants must be re-consented to the most current version of the ICF(s) 
during their participation in the study. 

A copy of the ICF(s) must be provided to the participant or the participant’s 
legally authorized representative. 

Participants who are rescreened are required to sign a new ICF.
The ICF may contain a separate section that addresses the use of remaining mandatory 
samples for optional exploratory research in accordance with SOP-GSKF-410. The 
investigator or authorized designee will explain to each participant the objectives of the 
exploratory research. Participants will be told that they are free to refuse to participate 
and may withdraw their consent at any time and for any reason during the storage period. 
A separate signature will be required to document a participant's agreement to allow any 
remaining specimens to be used for exploratory research. Participants who decline to 
participate will not provide this separate signature.
10.4.4.
Data Protection

Participants will be assigned a unique identifier by the sponsor. Any participant 
records or datasets that are transferred to the sponsor will contain the identifier 
only; participant names or any information which would make the participant 
identifiable will not be transferred. 

The participant must be informed that his/her personal study-related data will be 
used by the sponsor in accordance with local data protection law. The level of 
disclosure must also be explained to the participant. 

The participant must be informed that his/her medical records may be examined 
by Clinical Quality Assurance auditors or other authorized personnel appointed 
by the sponsor, by appropriate IRB/IEC members, and by inspectors from 
regulatory authorities.
10.4.5.
Publication Policy

The results of this study may be published or presented at scientific meetings. If 
this is foreseen, the investigator agrees to submit all manuscripts or abstracts to 
the sponsor before submission. This allows the sponsor to protect proprietary 
information and to provide comments.

The sponsor will comply with the requirements for publication of study results. 
In accordance with standard editorial and ethical practice, the sponsor will 
generally support publication of multicenter studies only in their entirety and not 
 
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as individual site data. In this case, a coordinating investigator will be 
designated by mutual agreement.

Authorship will be determined by mutual agreement and in line with 
International Committee of Medical Journal Editors authorship requirements.
10.4.6.
Dissemination of Clinical Study Data

Where required by applicable regulatory requirements, an investigator signatory 
will be identified for the approval of the clinical study report. The investigator 
will be provided reasonable access to statistical tables, figures, and relevant 
reports and will have the opportunity to review the complete study results at a 
VH/GSK site or other mutually-agreeable location.

VH/GSK will also provide the investigator with the full summary of the study 
results. The investigator is encouraged to share the summary results with the 
study participants, as appropriate.

The procedures and timing for public disclosure of the protocol and results 
summary and for development of a manuscript for publication for this study will 
be in accordance with VH/GSK Policy.

VH/GSK intends to make anonymized patient-level data from this study 
available to external researchers for scientific analyses or to conduct further 
research that can help advance medical science or improve patient care. This 
helps ensure the data provided by study participants are used to maximum effect 
in the creation of knowledge and understanding.
10.4.7.
Data Quality Assurance

All participant data relating to the study will be recorded on printed or electronic 
CRF unless transmitted to the sponsor or designee electronically (e.g., 
laboratory data). The investigator is responsible for verifying that data entries 
are accurate and correct by physically or electronically signing the CRF. 

The investigator must maintain accurate documentation (source data) that 
supports the information entered in the CRF. 

The investigator must permit study-related monitoring, audits, IRB/IEC review, 
and regulatory agency inspections and provide direct access to source data 
documents. 

Monitoring details describing strategy (e.g., risk-based initiatives in operations 
and quality such as Risk Management and Mitigation), methods, responsibilities, 
and requirements, including handling of noncompliance issues and monitoring 
techniques (central, remote, or on-site monitoring) are provided in the 
Monitoring Plan.

The sponsor or designee is responsible for the data management of this study 
including quality checking of the data. 

The sponsor assumes accountability for actions delegated to other individuals 
(e.g., contract research organizations).
 
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
Study monitors will perform ongoing source data verification to confirm that 
data entered into the CRF by authorized site personnel are accurate, complete, 
and verifiable from source documents; that the safety and rights of participants 
are being protected; and that the study is being conducted in accordance with the 
currently approved protocol and any other study agreements, ICH GCP, and all 
applicable regulatory requirements. 

Records and documents, including signed ICF, pertaining to the conduct of this 
study must be retained by the investigator for 25 years from the issue of the final 
Clinical Study Report/equivalent summary unless local regulations or 
institutional policies require a longer retention period. No records may be 
destroyed during the retention period without the written approval of the 
sponsor. No records may be transferred to another location or party without 
written notification to the sponsor.
10.4.8.
Source Documents

Source documents provide evidence for the existence of the participant and 
substantiate the integrity of the data collected. Source documents are filed at the 
investigator’s site.

Data reported on the CRF or entered in the eCRF that are transcribed from 
source documents must be consistent with the source documents or the 
discrepancies must be explained. The investigator may need to request previous 
medical records or transfer records, depending on the study. Also, current 
medical records must be available.

Definition of what constitutes source data can be found in the SRM.
10.4.9.
Study and Site Closure
VH/GSK or its designee reserves the right to close the study site or terminate the study at 
any time for any reason at the sole discretion of VH/GSK. Study sites will be closed upon 
study completion. A study site is considered closed when all required documents and 
study supplies have been collected and a study-site closure visit has been performed.
The investigator may initiate study-site closure at any time, provided there is reasonable 
cause and sufficient notice is given in advance of the intended termination.
Reasons for the early closure of a study site by the sponsor or investigator may include 
but are not limited to:

Failure of the investigator to comply with the protocol, the requirements of the 
IRB/IEC or local health authorities, the sponsor's procedures, or GCP guidelines

Inadequate recruitment of participants by the investigator

Discontinuation of further study intervention development
10.4.10.
Publication Policy

The results of this study may be published or presented at scientific meetings. If 
this is foreseen, the investigator agrees to submit all manuscripts or abstracts to 
 
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the sponsor before submission. This allows the sponsor to protect proprietary 
information and to provide comments.

The sponsor will comply with the requirements for publication of study results. 
In accordance with standard editorial and ethical practice, the sponsor will 
generally support publication of multicenter studies only in their entirety and not 
as individual site data. In this case, a coordinating investigator will be 
designated by mutual agreement.

Authorship will be determined by mutual agreement and in line with 
International Committee of Medical Journal Editors authorship requirements.
 
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10.5.
Appendix 5: Liver Safety: Required Actions and Follow-up 
Assessments
The procedures listed below are to be followed if a participant meets the liver chemistry 
stopping criteria defined in Section 7.1:

Immediately withdraw the participant from study intervention

Notify the VH/GSK Medical Monitor within 24 hours of learning of the 
abnormality to confirm the participant’s study intervention cessation and 
follow-up.

Complete the “Safety Follow-Up Procedures” listed below.

Complete the liver event CRFs. If the event also meets the criteria of an SAE 
(see Appendix 6), the SAE data collection tool will be completed separately 
with the relevant details.
Safety Follow-Up Procedures for participants with ALT ≥3 × ULN:

Monitor participants weekly until liver chemistries (ALT, aspartate 
aminotransferase [AST], alkaline phosphatase, bilirubin) resolve, stabilize, or 
return to within baseline values.
Safety Follow-Up Procedures for participants with ALT ≥3 × ULN and total 
bilirubin ≥2 × ULN (>35% direct bilirubin); or ALT ≥3 × ULN and INR1 >1.5:

This event is considered an SAE (see Appendix 6). Serum bilirubin fractionation 
should be performed if testing is available. If fractionation is unavailable, 
urinary bilirubin is to be measured via dipstick (a measurement of direct 
bilirubin, which would suggest liver injury).

Make every reasonable attempt to have participants return to the clinic within 
24 hours for repeat liver chemistries, additional testing, and close monitoring 
(with specialist or hepatology consultation recommended).

Monitor participants twice weekly until liver chemistries (ALT, AST, alkaline 
phosphatase, bilirubin) resolve, stabilize, or return to within baseline values.
In addition, for all participants with ALT ≥3 × ULN, every attempt must be made to 
also obtain the following:

Viral hepatitis serology including: Hepatitis A IgM antibody, Hepatitis B 
surface antigen, and Hepatitis B Core Antibody (IgM), Hepatitis C RNA, 
Cytomegalovirus IgM antibody, Epstein-Barr viral capsid antigen IgM antibody 
(or if unavailable, obtain heterophile antibody or monospot testing), Hepatitis E 
IgM antibody.

Blood sample for PK analysis, obtained within 48 hours of last dose. Record the 
date/time of the PK blood sample draw and the date/time of the last dose of 
study intervention prior to blood sample draw on the CRF. If the date or time of 
the last dose is unclear, provide the participant’s best approximation. If the 
date/time of the last dose cannot be approximated OR a PK sample cannot be 
 
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collected in the time period indicated above, do not obtain a PK sample. 
Instructions for sample handling and shipping are included in the SRM.

Serum creatine phosphokinase (CPK) and lactate dehydrogenase (LDH).

Fractionate bilirubin, if total bilirubin ≥2 × ULN.

Assess eosinophilia

Record the appearance or worsening of clinical symptoms of hepatitis (fatigue, 
nausea, vomiting, right upper quadrant pain or tenderness, fever, rash, or 
eosinophilia) on the AE CRF.

Record use of concomitant medications, acetaminophen, herbal remedies, other 
over-the-counter medications, or putative hepatotoxins on the Concomitant 
Medications CRF.

Record alcohol use on the Liver Events CRF.
The following are required for participants with ALT ≥3 × ULN and bilirubin 
≥2 × ULN (>35% direct) but are optional for other abnormal liver chemistries:

Anti-nuclear antibody, anti-smooth muscle antibody, and Type 1 anti-liver 
kidney microsomal antibodies.

Serum acetaminophen adduct HPLC assay (quantifies potential acetaminophen 
contribution to liver injury in participants with definite or likely acetaminophen 
use in the preceding week [James, 2009]).

Liver imaging (ultrasound, magnetic resonance, or computerized tomography) to 
evaluate liver disease.

The Liver Imaging and/or Liver Biopsy CRFs are also to be completed if these 
tests are performed.
 
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10.6.
Appendix 6: Adverse Events: Definitions and Procedures for 
Recording, Evaluating, Follow-up, and Reporting
10.6.1.
Definition of AE
AE Definition

An AE is any untoward medical occurrence in a clinical study participant, temporally 
associated with the use of a study intervention, whether or not considered related to 
the study intervention.

NOTE: An AE can therefore be any unfavorable and unintended sign (including an 
abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally 
associated with the use of a study intervention.
Events Meeting the AE Definition

Any abnormal laboratory test results (hematology, clinical chemistry, or urinalysis) or 
other safety assessments (e.g., ECG, radiological scans, vital signs measurements), 
including those that worsen from Baseline, considered clinically significant in the 
medical and scientific judgment of the investigator (i.e., not related to progression of 
underlying disease).

Exacerbation of a chronic or intermittent pre-existing condition including either an 
increase in frequency and/or intensity of the condition.

New conditions detected or diagnosed after study intervention administration even 
though it may have been present before the start of the study.

Signs, symptoms, or the clinical sequelae of a suspected DDI.

Signs, symptoms, or the clinical sequelae of a suspected overdose of either study 
intervention or a concomitant medication. Overdose per se will not be reported as an 
AE/SAE unless it is an intentional overdose taken with possible suicidal/self-harming 
intent. Such overdoses should be reported regardless of sequelae.
Events NOT Meeting the AE Definition 

Any clinically significant abnormal laboratory findings or other abnormal safety 
assessments which are associated with the underlying disease, unless judged by the 
investigator to be more severe than expected for the participant’s condition.

The disease/disorder being studied or expected progression, signs, or symptoms of the 
disease/disorder being studied, unless more severe than expected for the participant’s 
condition.

Medical or surgical procedure (e.g., endoscopy, appendectomy): the condition that 
leads to the procedure is the AE.

Situations in which an untoward medical occurrence did not occur (social and/or 
 
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convenience admission to a hospital).

Anticipated day-to-day fluctuations of pre-existing disease(s) or condition(s) present 
or detected at the start of the study that do not worsen.
10.6.2.
Definition of SAE
If an event is not an AE per definition above, then it cannot be an SAE even if serious 
conditions are met (e.g., hospitalization for signs/symptoms of the disease under study, 
death due to progression of disease).
A SAE is defined as any untoward medical occurrence that, at any dose:
o
Results in death
o
Is life-threatening
The term “life-threatening”' in the definition of “serious” refers to an event in which the 
participant was at risk of death at the time of the event. It does not refer to an event, 
which hypothetically might have caused death, if it were more severe.
Requires inpatient hospitalization or prolongation of existing hospitalization
In general, hospitalization signifies that the participant has been detained (usually 
involving at least an overnight stay) at the hospital or emergency ward for observation 
and/or treatment that would not have been appropriate in the physician’s office or 
outpatient setting. Complications that occur during hospitalization are AEs. If a 
complication prolongs hospitalization or fulfills any other serious criteria, the event is 
serious. When in doubt as to whether “hospitalization” occurred or was necessary, the AE 
should be considered serious.
Hospitalization for elective treatment of a pre-existing condition that did not worsen from 
Baseline is not considered an AE.
Results in persistent disability/incapacity

The term disability means a substantial disruption of a person’s ability to conduct 
normal life functions.

This definition is not intended to include experiences of relatively minor medical 
significance such as uncomplicated headache, nausea, vomiting, diarrhea, influenza, 
and accidental trauma (e.g., sprained ankle) which may interfere with or prevent 
everyday life functions but do not constitute a substantial disruption.
Is a congenital anomaly/birth defect
Other situations:

Medical or scientific judgment should be exercised in deciding whether SAE 
reporting is appropriate in other situations such as important medical events that may 
not be immediately life-threatening or result in death or hospitalization but may 
 
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jeopardize the participant or may require medical or surgical intervention to prevent 
1 of the other outcomes listed in the above definition. These events should usually be 
considered serious.
Examples of such events include invasive or malignant cancers, intensive treatment 
in an emergency room or at home for allergic bronchospasm, blood dyscrasias or 
convulsions that do not result in hospitalization, or development of drug dependency 
or drug abuse.
10.6.3.
Recording and Follow-Up of AE and SAE
AE and SAE Recording

When an AE/SAE occurs, it is the responsibility of the investigator to review all 
documentation (e.g., hospital progress notes, laboratory, and diagnostics reports) 
related to the event.

The investigator will then record all relevant AE/SAE information in the CRF.

It is not acceptable for the investigator to send photocopies of the participant’s 
medical records to VH/GSK in lieu of completion of the GSK AE/SAE CRF page.

There may be instances when copies of medical records for certain cases are 
requested by VH/GSK. In this case, all participant identifiers, with the exception of 
the participant number, will be redacted on the copies of the medical records before 
submission to VH/GSK.

The investigator will attempt to establish a diagnosis of the event based on signs, 
symptoms, and/or other clinical information. Whenever possible, the diagnosis (not 
the individual signs/symptoms) will be documented as the AE/SAE.
Assessment of Intensity
The investigator will make an assessment of intensity for each AE and SAE reported 
during the study using the DAIDS grading table Version 2.1, March 2017 
(https://rsc.tech-res.com/docs/default-source/safety/daidsgradingcorrecetedv21.pdf) and 
assign it to 1 of the following categories: 

Mild: no or minimal interference with usual social & functional activities 

Moderate: greater than minimal interference with usual social and functional 
activities

Severe: inability to perform usual social and functional activities. An AE that is 
assessed as severe should not be confused with an SAE. Severe is a category utilized 
for rating the intensity of an event; and both AE and SAE can be assessed as severe.

Life Threatening: inability to perform basic self-care functions
An event is defined as “serious” when it meets at least 1 of the predefined outcomes as 
described in the definition of an SAE, NOT when it is rated as severe.
 
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Assessment of Causality

The investigator is obligated to assess the relationship between study intervention and 
each occurrence of each AE/SAE.

A “reasonable possibility” of a relationship conveys that there are facts, evidence, 
and/or arguments to suggest a causal relationship, rather than a relationship cannot be 
ruled out.

The investigator will use clinical judgment to determine the relationship.

Alternative causes, such as underlying disease(s), concomitant therapy, and other risk 
factors, as well as the temporal relationship of the event to study intervention 
administration will be considered and investigated.

The investigator will also consult the CIB and/or Product Information, for marketed 
products, in his/her assessment.

For each AE/SAE, the investigator must document in the medical notes that he/she 
has reviewed the AE/SAE and has provided an assessment of causality.

There may be situations in which an SAE has occurred and the investigator has 
minimal information to include in the initial report to VH/GSK. However, it is very 
important that the investigator always make an assessment of causality for every 
event before the initial transmission of the SAE data to VH/GSK.

The investigator may change his/her opinion of causality in light of follow-up 
information and send an SAE follow-up report with the updated causality assessment.

The causality assessment is 1 of the criteria used when determining regulatory 
reporting requirements.
Follow-up of AE and SAE

The investigator is obligated to perform or arrange for the conduct of supplemental 
measurements and/or evaluations as medically indicated or as requested by VH/GSK 
to elucidate the nature and/or causality of the AE or SAE as fully as possible. This 
may include additional laboratory tests or investigations, histopathological 
examinations, or consultation with other health care professionals.

If a participant dies during participation in the study or during a recognized follow-up 
period, the investigator will provide VH/GSK with a copy of any post-mortem 
findings including histopathology.

New or updated information will be recorded in the originally completed CRF.

The investigator will submit any updated SAE data to VH/GSK within 24 hours of 
receipt of the information.
 
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10.6.4.
Reporting of SAE to VH/GSK
SAE Reporting to VH/GSK via Electronic Data Collection Tool

The primary mechanism for reporting SAE to VH/GSK will be the electronic data 
collection tool.

If the electronic system is unavailable, then the site will use the paper SAE data 
collection tool (see next section) in order to report the event within 24 hours.

The site will enter the SAE data into the electronic system as soon as it becomes 
available.

The investigator or medically-qualified sub-investigator must show evidence within 
the electronic CRF (e.g., check review box, signature, etc.) of review and verification 
of the relationship of each SAE to study intervention/study participation (causality) 
within 72 hours of SAE entry into the eCRF.

After the study is completed at a given site, the electronic data collection tool will be 
taken off-line to prevent the entry of new data or changes to existing data.

If a site receives a report of a new SAE from a study participant or receives updated 
data on a previously reported SAE after the electronic data collection tool has been 
taken off-line, then the site can report this information on a paper SAE form (see next 
section) or to the medical monitor by telephone.

Contacts for SAE reporting can be found in the SRM.
SAE Reporting to VH/GSK via Paper CRF

Facsimile transmission of the SAE paper CRF is the preferred method to transmit 
this information to the medical monitor.

In rare circumstances and in the absence of facsimile equipment, notification by 
telephone is acceptable with a copy of the SAE data collection tool sent by overnight 
mail or courier service.

Initial notification via telephone does not replace the need for the investigator to 
complete and sign the SAE CRF pages within the designated reporting time frames.

Contacts for SAE reporting can be found in SRM.
 
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10.7.
Appendix 7: Genetics
USE/ANALYSIS OF DNA

Genetic variation may impact a participant’s response to study intervention, 
susceptibility, severity, and progression of disease. Variable response to study 
intervention may be due to genetic determinants that impact drug absorption, 
distribution, metabolism, and excretion; mechanism of action of the drug; 
disease etiology; and/or molecular subtype of the disease being treated. 
Therefore, where local regulations and IRB/IEC allow, a blood sample will be 
collected for DNA analysis.

DNA samples will be used for research related to GSK3640254 or HIV and 
related diseases. They may also be used to develop tests/assays including 
diagnostic tests related to GSK3640254 or HIV MIs and HIV. Genetic research 
may consist of the analysis of 1 or more candidate genes or the analysis of 
genetic markers throughout the genome or analysis of the entire genome (as 
appropriate).

DNA samples will be analyzed if it is hypothesized that this may help further 
understand the clinical data. 

The samples may be analyzed as part of a multi-study assessment of genetic 
factors involved in the response to GSK3640254 or study interventions of this 
class. The results of genetic analyses may be reported in the clinical study report 
or in a separate study summary.

The sponsor will store the DNA samples in a secure storage space with adequate 
measures to protect confidentiality. 

The samples will be retained while research on GSK3640254 (or study 
interventions of this class) or HIV continues but no longer than 15 years after 
the last participant’s last visit or other period as per local requirements.
 
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11.
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