A Phase 2 Randomized, Open-label Study to Evaluate the Safety and Efficacy of Broadly Neutralizing Antibodies (bNAbs) GS-5423 and GS-2872 in Combination With the Capsid Inhibitor Lenacapavir as Long-Acting Treatment Dosed Every 6 Months in Virologically Suppressed Adults With HIV-1 Infection
Phase: PHASE2
Conditions: HIV Infection
Sponsor: Gilead Sciences

CLINICAL STUDY PROTOCOL
Study Title:
A Phase 2 Randomized, Open-label Study to Evaluate the Safety 
and Efficacy of Broadly Neutralizing Antibodies (bNAbs) 
GS-5423 and GS-2872 in Combination With the Capsid Inhibitor 
Lenacapavir as Long-Acting Treatment Dosed Every 6 Months in 
Virologically Suppressed Adults With HIV-1 Infection 
Plain Language Short 
Title:
A Phase 2 Study of GS-5423 and GS-2872 in Combination With 
Capsid Inhibitor Lenacapavir in Virologically Suppressed Adults 
With HIV-1 Infection 
Sponsor:
Gilead Sciences, Inc.
333 Lakeside Drive
Foster City, CA 94404
USA
IND Number:
163095
EU CT Number:
Not Applicable
ClinicalTrials.gov 
Identifier:
Not Available
Diagnosis or Condition:
Virologically Suppressed Adults With HIV-1 Infection
Protocol ID:
GS-US-536-5939
Contact Information:
The medical monitor name and contact information will be 
provided on the Key Study Team Contact List.
Protocol Version/Date:
Amendment 3:             13 May 2024
Amendment History:
Original:
02 November 2022 
Amendment 1: 18 January 2023
Amendment 2: 26 June 2023
A high-level summary of the changes in each amendment is 
provided in Appendix 11.7.
Country-Specific 
Requirements:
Country-specific requirements, as applicable, are listed in 
Appendix 11.6.
GILEAU 

This study will be conducted under United States Food and Drug Administration investigational 
new drug application regulations (21 Code of Federal Regulations Part 312); however, sites 
located in the European Economic Area, the United Kingdom, and Switzerland are not included 
under the investigational new drug application and are not considered to be investigational new 
drug application sites.
This study will be conducted in compliance with this protocol and in accordance with the ethical 
principles that have their origin in the Declaration of Helsinki, and that are consistent with 
International Council for Harmonisation (ICH) Good Clinical Practice (GCP) and applicable 
regulatory requirements.
CONFIDENTIALITY STATEMENT
The information contained in this document, particularly unpublished data, is the property or 
under control of Gilead Sciences, Inc., and is provided to you in confidence as an investigator, 
potential investigator, or consultant, for review by you, your staff, and an applicable 
institutional review board or independent ethics committee. The information is only to be used 
by you in connection with authorized clinical studies of the investigational drug described in 
the protocol. You will not disclose any of the information to others without written 
authorization from Gilead Sciences, Inc., except to the extent necessary to obtain informed 
consent from those persons to whom the drug may be administered.

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TABLE OF CONTENTS
TABLE OF CONTENTS................................................................................................................................................3
LIST OF IN-TEXT TABLES .........................................................................................................................................6
LIST OF IN-TEXT FIGURES........................................................................................................................................6
LIST OF ABBREVIATIONS AND DEFINITION OF TERMS ...................................................................................7
PROTOCOL SYNOPSIS..............................................................................................................................................10
STUDY SCHEMA........................................................................................................................................................16
STUDY PROCEDURES TABLE ................................................................................................................................17
1.
INTRODUCTION................................................................................................................................................28
1.1.
Background..............................................................................................................................................28
1.2.
Background on Study Interventions ........................................................................................................29
1.2.1.
Lenacapavir ...........................................................................................................................29
1.2.2.
GS-5423.................................................................................................................................30
1.2.3.
GS-2872.................................................................................................................................30
1.2.4.
Clinical Studies of Lenacapavir With GS-5423 and GS-2872..............................................31
1.3.
Rationale for This Study..........................................................................................................................33
1.4.
Rationale for Dose Selection...................................................................................................................33
1.4.1.
GS-5423 and GS-2872 ..........................................................................................................33
1.4.2.
Lenacapavir ...........................................................................................................................35
1.5.
Risk/Benefit Assessment for the Study ...................................................................................................37
1.6.
Compliance..............................................................................................................................................38
2.
OBJECTIVES AND ENDPOINTS......................................................................................................................39
3.
STUDY DESIGN.................................................................................................................................................40
3.1.
Study Design Overview...........................................................................................................................40
3.1.1.
Randomized Phase.................................................................................................................40
3.1.2.
Extension Phase.....................................................................................................................40
3.2.
Duration of Intervention..........................................................................................................................41
3.3.
Protocol-Specific Discontinuation Criteria .............................................................................................41
3.3.1.
Criteria for Early Discontinuation for the Individual Participants ........................................41
3.3.2.
Criteria for Early Discontinuation of the Study ....................................................................42
3.3.3.
Loss to Follow-up..................................................................................................................42
3.4.
Definitions for Time of Primary Endpoint and End of Study .................................................................42
3.4.1.
Primary Endpoint...................................................................................................................42
3.4.2.
End of Study..........................................................................................................................42
3.5.
Poststudy Care.........................................................................................................................................43
3.6.
Source Data .............................................................................................................................................43
4.
PARTICIPANT POPULATION..........................................................................................................................44
4.1.
Number of Participants and Participant Selection...................................................................................44
4.1.1.
Participant Replacement........................................................................................................44
4.2.
Inclusion Criteria.....................................................................................................................................44
4.3.
Exclusion Criteria....................................................................................................................................46
5.
STUDY INTERVENTIONS AND CONCOMITANT MEDICATIONS ...........................................................48
5.1.
Randomization.........................................................................................................................................48
5.1.1.
Randomization.......................................................................................................................48
5.1.2.
Blinding .................................................................................................................................48

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5.2.
Description and Handling of Lenacapavir, GS-5423, and GS-2872.......................................................48
5.2.1.
Formulation ...........................................................................................................................48
5.2.2.
Packaging and Labeling ........................................................................................................49
5.2.3.
Storage and Handling ............................................................................................................49
5.3.
Dosage and Administration .....................................................................................................................50
5.3.1.
Additional IV Infusion Instructions.......................................................................................54
5.3.2.
Missed or Delayed Study Drug Doses...................................................................................55
5.4.
Prior and Concomitant Medications........................................................................................................55
5.5.
Accountability for Study Drug(s)............................................................................................................57
5.5.1.
Study Drug Return or Disposal .............................................................................................57
6.
STUDY PROCEDURES......................................................................................................................................58
6.1.
Informed Consent ....................................................................................................................................58
..................................................................58
6.2.
Screening, Participant Enrollment, and Treatment Assignment .............................................................58
6.3.
Instructions for Study Procedures ...........................................................................................................59
6.3.1.
Adverse Events......................................................................................................................59
6.3.2.
Concomitant Medications......................................................................................................59
6.3.3.
Electrocardiograms................................................................................................................59
6.3.4.
Medical History and Demography ........................................................................................59
6.3.5.
Clinical Laboratory Assessments ..........................................................................................60
6.3.6.
Pharmacokinetics...................................................................................................................61
6.3.7.
Immunogenicity Assessments ...............................................................................................63
6.3.8.
Biomarker Testing.................................................................................................................63
6.3.9.
Clinical Virology...................................................................................................................64
6.3.10.
Patient-Reported Outcomes...................................................................................................65
6.3.11.
Assessments for Early Study Drug Discontinuation .............................................................66
6.4.
Poststudy Care.........................................................................................................................................67
6.5.
Sample Storage........................................................................................................................................67
7.
ADVERSE EVENTS AND TOXICITY MANAGEMENT................................................................................68
7.1.
Definitions of Adverse Events and Serious Adverse Events...................................................................68
7.1.1.
Adverse Events......................................................................................................................68
7.1.2.
Serious Adverse Events.........................................................................................................68
7.1.3.
Study Drugs and Gilead Concomitant Medications Special Situations 
Reports...................................................................................................................................69
7.2.
Assessment of Adverse Events and Serious Adverse Events..................................................................70
7.2.1.
Assessment of Causality for Study Drugs and Procedures ...................................................70
7.2.2.
Assessment of Severity..........................................................................................................70
7.3.
Investigator Reporting Requirements and Instructions ...........................................................................70
7.3.1.
Requirements for Collection Before Study Drug Initiation ..................................................70
7.3.2.
Adverse Events......................................................................................................................71
7.3.3.
Serious Adverse Events.........................................................................................................71
7.3.4.
Study Drug Special Situations Reports .................................................................................71
7.3.5.
Concomitant Medications Reports ........................................................................................71
7.4.
Reporting Process for Serious Adverse Events and Special Situations Reports.....................................72
7.4.1.
Serious Adverse Event Reporting Process ............................................................................72
7.4.2.
Special Situations Reporting Process ....................................................................................73
7.5.
Gilead Reporting Requirements ..............................................................................................................74
7.6.
Clinical Laboratory Abnormalities and Other Abnormal Assessments as Adverse Events or 
Serious Adverse Events...........................................................................................................................75
7.7.
Toxicity Management..............................................................................................................................76
7.7.1.
Management of ISRs of Grade 3 or Higher or Persisting for More Than 
26 Weeks...............................................................................................................................77
CCI
CCI
1111 

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7.7.2.
Management of Ophthalmologic Toxicities/Symptoms of Ocular Disease..........................77
7.7.3.
Management of Other Toxicities...........................................................................................77
7.8.
Internal Safety Team ...............................................................................................................................79
8.
STATISTICAL CONSIDERATIONS.................................................................................................................80
8.1.
Analysis Objectives and Endpoints.........................................................................................................80
8.2.
Planned Analyses.....................................................................................................................................80
8.2.1.
Interim Analysis ....................................................................................................................80
8.2.2.
Primary Analysis ...................................................................................................................81
8.2.3.
Final Analysis........................................................................................................................81
8.3.
Analysis Conventions..............................................................................................................................81
8.3.1.
Analysis Sets .........................................................................................................................81
8.3.2.
Data Handling Conventions ..................................................................................................82
8.4.
Demographic and Baseline Characteristics Analysis..............................................................................82
8.5.
Efficacy Analysis.....................................................................................................................................83
8.5.1.
Primary Analysis ...................................................................................................................83
8.5.2.
Secondary Analyses...............................................................................................................83
8.6.
Safety Analysis........................................................................................................................................83
8.6.1.
Extent of Exposure ................................................................................................................83
8.6.2.
Adverse Events......................................................................................................................84
8.6.3.
Laboratory Evaluations .........................................................................................................84
8.6.4.
Other Safety Evaluations.......................................................................................................84
8.7.
Adjustments for Multiplicity ...................................................................................................................84
8.8.
Pharmacokinetic Analysis .......................................................................................................................85
8.9.
Immunogenicity Analysis........................................................................................................................85
8.10.
Patient-reported Outcomes Analysis .......................................................................................................85
8.11.
Sample Size .............................................................................................................................................85
8.12.
Data Monitoring Committee....................................................................................................................86
9.
RESPONSIBILITIES...........................................................................................................................................87
9.1.
Investigator Responsibilities ...................................................................................................................87
9.1.1.
Good Clinical Practice...........................................................................................................87
9.1.2.
Financial Disclosure ..............................................................................................................87
9.1.3.
Institutional Review Board/Independent Ethics Committee Review and 
Approval................................................................................................................................87
9.1.4.
Informed Consent ..................................................................................................................87
9.1.5.
Confidentiality.......................................................................................................................88
9.1.6.
Study Files and Retention of Records ...................................................................................88
9.1.7.
Case Report Forms ................................................................................................................90
9.1.8.
Investigator Inspections.........................................................................................................90
9.1.9.
Protocol Compliance .............................................................................................................90
9.2.
Sponsor Responsibilities .........................................................................................................................91
9.2.1.
Protocol Modifications ..........................................................................................................91
9.2.2.
Study Reports and Publications.............................................................................................91
9.3.
Joint Investigator/Sponsor Responsibilities ............................................................................................91
9.3.1.
Payment Reporting ................................................................................................................91
9.3.2.
Access to Information for Monitoring...................................................................................91
9.3.3.
Access to Information for Auditing or Inspections ...............................................................92
9.3.4.
Study Discontinuation ...........................................................................................................92
9.3.5.
Data Protection ......................................................................................................................92
10.
REFERENCES.....................................................................................................................................................93
11.
APPENDICES......................................................................................................................................................95

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11.1.
Investigator Signature Page.....................................................................................................................96
11.2.
Disaster and Public Health Emergency Risk Assessment and Mitigation Plan ......................................97
11.3.
Pregnancy Precautions, Definition of Childbearing Potential, and Contraceptive Requirements ........100
11.4.
Toxicity Grading Scale for Severity of Adverse Events and Laboratory Abnormalities......................103
11.5.
Management of Clinical and Laboratory Adverse Events ....................................................................104
11.6.
Country-Specific Requirements ............................................................................................................105
11.7.
Amendment History ..............................................................................................................................106
11.7.1.
Amendment 3 (13 May 2024) .............................................................................................106
11.7.2.
Amendment 2 (26 June 2023) .............................................................................................107
11.7.3.
Amendment 1 (18 January 2023) ........................................................................................108
11.8.
Sponsor Signature Page.........................................................................................................................109
LIST OF IN-TEXT TABLES
Table 1.
Study Procedures Table (Treatment Group 1).........................................................................17
Table 2.
Study Procedures Table (Treatment Group 3).........................................................................23
Table 3.
Treatment Group 1 Treatment Table.......................................................................................52
Table 4.
Treatment Group 3 Treatment Table.......................................................................................53
Table 5.
List of Representative Medications That are Prohibited or To Be Used With Caution 
Due to the Potential for Drug-Drug Interaction With LEN.....................................................55
Table 6.
Laboratory Analytes ................................................................................................................60
Table 7.
The Common Terminology Criteria for Adverse Events Version 5 Grading Scale................76
LIST OF IN-TEXT FIGURES
Figure 1.
Study Schema* ........................................................................................................................16
Figure 2.
Simulated Plasma Profile of LEN Following the Proposed SC LEN Regimen 
Administered Every 26 Weeks With an Oral PK Load on Days 1 and 2................................36

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LIST OF ABBREVIATIONS AND DEFINITION OF TERMS 
ADA
antidrug antibody
AE
adverse event
AIDS
acquired immunodeficiency syndrome
ALT
alanine aminotransferase
ART
antiretroviral therapy
ARV
antiretroviral
AST
aspartate aminotransferase
AUC
area under the concentration versus time curve
AUC0-t
partial area under the concentration versus time curve from time “0” to time “t”
AUClast
area under the concentration versus time curve from time zero to the last quantifiable 
concentration
BCRP
breast cancer resistance protein
bNAb
broadly neutralizing antibody
CD4
clusters of differentiation 4
CD8
clusters of differentiation 8
CI
confidence interval
Cmax
maximum observed concentration of drug
CRF
case report form
CSR
clinical study report
CTCAE
Common Terminology Criteria for Adverse Events
Ctrough
concentration at the end of the dosing interval
CYP
cytochrome P450 enzyme
DAIDS
Division of AIDS
DMC
data monitoring committee
DNA
deoxyribonucleic acid
ECG
electrocardiogram
eCRF
electronic case report form
EDC
electronic data capture
eGFR
estimated glomerular filtration rate
ESDD
early study drug discontinuation
EU
European Union
Fab
antigen-binding fragment
FAS
Full Analysis Set
Fc
crystallizable fragment
FcRn
neonatal Fc receptor
FDA
Food and Drug Administration
FIH
first in human
FSH
follicle-stimulating hormone
GCP
Good Clinical Practice

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Gilead
Gilead Sciences
HBV
hepatitis B virus
HCV
hepatitis C virus
HIV
human immunodeficiency virus
HIV-1
human immunodeficiency virus type 1
HIVDQoL
HIV-dependent quality of life
HIVTPQ
HIV Treatment Preference Questionnaire
HIVTSQ
HIV Treatment Satisfaction Questionnaire
HIVTSQc
HIV Treatment Satisfaction Questionnaire change version
HLT
high-level term
HTE
heavily treatment-experienced
IB
investigator’s brochure
IC90
90% inhibitory concentration
ICF
informed consent form
ICH
International Council for Harmonisation (of Technical Requirements for 
Pharmaceuticals for Human Use)
IND
investigational new drug
IQ
inhibitory quotient
IRB
institutional review board
IRT
interactive response technology
ISR
injection site reaction
IV
intravenous
LEN
lenacapavir
LLOQ
lower limit of quantitation
mAb
monoclonal antibody
MedDRA
Medical Dictionary for Regulatory Activities
PBMC
peripheral blood mononuclear cell
P-gp
P-glycoprotein
PK
pharmacokinetic(s)
POC
proof of concept
PRO
patient-reported outcome
PSD
post study drug
PT
preferred term
PWH
people with HIV-1
RNA
ribonucleic acid
SAC
Safety Assessment Committee
SAE
serious adverse event
SC
subcutaneous
SD
standard deviation
SOC
system organ class

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SSR
special situation report
t1/2
terminal elimination half-life
TEAE
treatment-emergent adverse event
TESAE
treatment-emergent serious adverse event
Tmax
time (observed time point) of Cmax
TN
treatment naive
UGT1A1
uridine diphosphate glucuronosyltransferase 1A1
ULN
upper limit of normal
US, USA
United States, United States of America
VF
virologic failure
VR
virologic rebound

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PROTOCOL SYNOPSIS
Gilead Sciences, Inc.
333 Lakeside Drive
Foster City, CA 94404
Study Title: A Phase 2 Randomized, Open-label, Study to Evaluate the Safety and Efficacy of 
Broadly Neutralizing Antibodies (bNAbs) GS-5423 and GS-2872 in Combination With the 
Capsid Inhibitor Lenacapavir as Long-Acting Treatment Dosed Every 6 Months in 
Virologically Suppressed Adults With HIV-1 Infection 
Short Title: A Phase 2 Study of GS-5423 and GS-2872 in Combination With Capsid Inhibitor 
Lenacapavir in Virologically Suppressed Adults With HIV-1 Infection 
IND Number: 163095 
EU CT Number: Not Applicable
ClinicalTrials.gov Identifier: Not Available
Study Centers Planned:
Approximately 55 centers globally
Objectives and Endpoints: 
Primary Objective
Primary Endpoint
•
To evaluate the efficacy of switching to a 
regimen of lenacapavir (LEN, Sunlenca®), 
GS-5423, and GS-2872 versus continuing on 
baseline oral antiretroviral (ARV) therapy (ART) 
as determined by the proportion of participants 
with HIV-1 RNA ≥ 50 copies/mL at Week 26
•
Proportion of participants with HIV-1 RNA 
≥ 50 copies/mL at Week 26 as determined by the 
United States (US) Food and Drug 
Administration (FDA)-defined snapshot 
algorithm
Secondary Objectives
Secondary Endpoints
•
To evaluate the efficacy of switching to a 
regimen of LEN, GS-5423, and GS-2872 versus 
continuing on baseline oral ART as determined 
by the proportion of participants with HIV-1 
RNA ≥ 50 copies/mL at Week 52
•
To evaluate the efficacy of switching to a 
regimen of LEN, GS-5423, and GS-2872 versus 
continuing on baseline oral ART as determined 
by the proportion of participants maintaining 
virologic suppression (HIV-1 RNA 
< 50 copies/mL) at Weeks 26 and 52
•
Proportion of participants with HIV-1 RNA 
≥ 50 copies/mL at Week 52 as determined by the 
US FDA‑defined snapshot algorithm
•
Proportion of participants with HIV-1 RNA 
< 50 copies/mL at Weeks 26 and 52 as 
determined by the US FDA-defined snapshot 
algorithm
•
Changes from baseline in CD4+ T-cell counts at 
Weeks 26 and 52
•
Proportion of participants experiencing 
treatment-emergent adverse events (TEAEs) 

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Secondary Objectives
Secondary Endpoints
•
To evaluate CD4+ T-cell counts at Weeks 26 and 
52
•
To evaluate the safety and tolerability of the 
2 treatment groups
•
To evaluate the pharmacokinetics (PK) of 
GS-5423, GS-2872, and LEN
•
To evaluate the immunogenicity of GS-5423 and 
GS-2872
•
Trough concentrations at Weeks 26 and 52 and 
PK parameters (AUC0-t, AUClast, t1/2, Cmax, and 
Tmax) for GS-5423, GS-2872, and LEN as 
appropriate
•
Incidence of anti–GS-5423 and anti–GS-2872 
antibodies 
Study Design:This is a Phase 2, randomized, open-label, active-controlled, multicenter study 
to evaluate the safety and efficacy of the long-acting regimen of LEN, GS-5423, and GS-2872. 
The study will include approximately 75 participants with sensitivity to GS-5423 and GS-2872 
by protocol-defined criteria, who meet all eligibility criteria, and who will be randomized 
without stratification in a 2:1 ratio to Treatment Groups 1 and 3.
Randomized Phase
Treatment Group 1
•
Participants in Treatment Group 1 will receive the long-acting regimen consisting of LEN, 
GS-5423, and GS-2872. 
•
Participants will discontinue their baseline oral ART following administration of the 
complete study drugs on Day 1 (oral LEN, subcutaneous [SC] injectable LEN, and 
intravenous [IV] infusions of GS-5423 and GS-2872) and will self-administer oral LEN on 
Day 2. Participants will also receive study drug (SC LEN and IV infusions of GS-5423 and 
GS-2872) at Week 26.
Treatment Group 3
•
Participants in Treatment Group 3 will continue their baseline oral ART as prescribed 
during the randomized phase. 
Extension Phase
Treatment Group 1
•
At Week 52, participants in Treatment Group 1 who receive the study drugs of LEN, 
GS-5423, and GS-2872, and complete the study through Week 52 with HIV-1 RNA 
< 50 copies/mL at the preceding Week 50 visit, will be given the option to participate in 
the study extension phase. In the study extension phase, participants will continue to 
receive their randomized study drugs every 26 weeks.
•
Participants who elect not to participate or are not eligible to participate in the extension 
phase will resume their baseline oral ART (or appropriate regimen selected by the 
investigator). 
Treatment Group 3

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Participants in Treatment Group 3 who complete the study through Week 52 (with HIV-1 
RNA < 50 copies/mL at the preceding Week 50 visit and in the absence of confirmed virologic 
rebound (VR) throughout the randomized phase of the study) will be given the option to 
participate in the extension phase and receive the study drugs of LEN, GS-5423, and GS-2872 
every 26 weeks. Treatment with study drugs will begin at Week 52 and at that time the 
baseline oral ART regimen will be discontinued. 
Number of Participants Planned: Approximately 75 total participants. 
Target Population: Adults with HIV-1 on ART with demonstrated virologic suppression 
(HIV-1 RNA < 50 copies/mL) for at least 12 months prior to screening who meet protocol 
criteria for sensitivity to the bNAbs.
Duration of Intervention: Fifty-two weeks during the randomized phase. Participants who 
are eligible to participate in the extension phase have the option to continue to receive study 
drug until the product becomes accessible to participants through an access program, is 
commercially available, or Gilead Sciences, Inc. (Gilead) elects to discontinue the study, 
whichever occurs first. 
Diagnosis and Main Eligibility Criteria:
•
Between 18 and 65 years of age, inclusive, at screening.
•
Body weight ≥ 40 kg at Screening Visit 2.
•
On stable oral ART consisting of no more than 2 drug classes (with the exception of 
pharmacologic boosters cobicistat or ritonavir) for ≥ 1 year prior to Screening Visit 2. 
A change in ART regimen ≥ 28 days prior to Screening Visit 2 for reasons other than 
virologic failure (VF) (eg, tolerability, simplification, drug-drug interaction profile) is 
allowed.
•
No clinically significant documented historical resistance to the current ART regimen 
with the exception of isolated nucleoside reverse transcriptase inhibitor mutations 
including M184V or ≤ 2 thymidine analog mutations (TAMs: M41L, D67N, K70R, 
L210W, T215Y, and/or K219Q).
•
Plasma HIV-1 RNA < 50 copies/mL at Screening Visit 2.
•
Documented plasma HIV-1 RNA < 50 copies/mL for ≥ 12 months preceding 
Screening Visit 2 (or undetectable HIV-1 RNA level according to the local assay being 
used if the limit of detection is ≥ 50 copies/mL). Virologic elevations of 
≥ 50 copies/mL (transient detectable viremia or “blips”) prior to screening are 
acceptable.
o
If HIV-1 sensitivity testing results are from > 12 months prior to screening 
(Inclusion Criterion 8), then documented plasma HIV-1 RNA < 50 copies/mL 
encompassing the time from sensitivity testing will be required.

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•
HIV-1 sensitivity results from screening or from the Study GS-US-536-5816 within 
36 months prior to Screening Visit 2 meeting specific criteria:
o
Proviral phenotypic sensitivity to both GS-5423 and GS-2872 by the 
PhenoSense Assay (Monogram Biosciences). GS-5423 phenotypic sensitivity is 
defined as 90% inhibitory concentration (IC90) ≤ 2 µg/mL; GS-2872 phenotypic 
sensitivity is defined as IC90 ≤ 2 µg/mL.
•
CD4+ T-cell count ≥ 200 cells/µL at Screening Visit 2.
•
Availability of a fully active alternative ART regimen, in the opinion of the 
investigator, in the event of discontinuation of the current ART regimen with 
development of resistance.
Participants who meet any of the following exclusion criteria are not eligible to be enrolled in 
this study:
•
Any prior receipt of LEN or a bNAb for HIV-1 treatment. 
•
Receipt of long-acting injectable ARV within 6 months of the Screening Visit 2.
•
Hepatitis C virus (HCV) antibody positive and HCV RNA detectable.
•
Chronic hepatitis B virus (HBV) infection, as determined by either: positive HBV 
surface antigen and negative HBV surface antibody, regardless of HBV core antibody 
status, at the screening visit, or positive HBV core antibody, negative HBV surface 
antibody regardless of HBV surface antigen status, at Screening Visit 2.
Study Procedures/Frequency: See Table 1 and Table 2.
Test Product, Dose, and Mode of Administration: Oral LEN, SC LEN injections, GS-5423 
and GS-2872 IV infusions.
Treatment Group 1:
On Day 1, oral LEN 600 mg, SC LEN 927 mg, IV GS-5423 2550 mg and IV GS-2872 
2550 mg will be administered. On Day 2, oral LEN 600 mg will be self-administered at home. 
At Weeks 26 and 52 and every 26 weeks during the extension phase SC LEN 927 mg, 
IV GS-5423 2550 mg, and IV GS-2872 2550 mg will be administered.
Treatment Group 3:
Participants in Treatment Group 3 will stay on their baseline oral ART regimen through 
Week 52. At Week 52, eligible participants will be administered oral LEN 600 mg, SC LEN 
927 mg, IV GS-5423 2550 mg, and IV GS-2872 2550 mg. At Week 52 + 1 day, oral LEN 
600 mg will be self-administered at home. During the extension phase, SC LEN 927 mg, 
IV GS-5423 2550 mg, and IV GS-2872 2550 mg will be administered every 26 weeks.
Reference Therapy, Dose, and Mode of Administration: Participants in Treatment Group 3 
will continue on their baseline oral ART.

Lenacapavir, GS-5423, GS-2872
Protocol GS-US-536-5939
Final
Gilead Sciences, Inc. 
Amendment 3
CONFIDENTIAL
Page 14
13 May 2024
Statistical Methods: 
The primary efficacy endpoint is the proportion of participants with HIV-1 
RNA ≥ 50 copies/mL at Week 26 as defined by the FDA-defined snapshot algorithm {U. S. 
Department of Health and Human Services 2015}. 
The 2-sided 95% CI of the difference in the proportion of participants with HIV-1 RNA 
≥ 50 copies/mL at Week 26 between Treatment Group 1 and Treatment Group 3 will be 
constructed based on an unconditional exact method using 2 inverted 1-sided tests {Chan 
1999}.
The proportion of participants with HIV-1 RNA ≥ 50 copies/mL at Week 52 and the 
proportion of participants with HIV-1 RNA < 50 copies/mL at Weeks 26 and 52 as determined 
by the US FDA-defined snapshot algorithm will be analyzed using the same methods as for 
the primary efficacy endpoint.
The changes from baseline in CD4+ T-cell count at Week 26 and Week 52 will be 
summarized by treatment group using descriptive statistics. The differences in changes from 
baseline in CD4+ T-cell count between the treatment groups (Treatment Group 1 versus 
Treatment Group 3) and the associated 95% CIs will be constructed using analysis of 
covariance models, including baseline CD4+ T-cell count as a covariate and treatment 
(Treatment Group 1 versus Treatment Group 3) as a fixed effect in the models. 
The number and proportion of participants experiencing TEAEs, serious adverse events 
(SAEs), and AEs leading to permanent study drug discontinuation, and treatment-emergent 
laboratory abnormalities will be summarized by treatment.
The incidence of anti-GS-5423 and anti-GS-2872 antibodies will be summarized by treatment 
group. 
For the PK analyses, the serum or plasma concentrations of each analyte (GS-5423, GS-2872, 
and LEN [and metabolites, if applicable]) over time, including trough concentrations at 
Weeks 26 and 52, will be listed and summarized by nominal time and treatment group using 
descriptive statistics. PK parameters (AUC0-t, AUClast, t1/2, Cmax, Tmax, as appropriate) will be 
listed and summarized by treatment group using descriptive statistics. Additional population 
PK analysis may be performed, as appropriate.
Independent Data Monitoring Committee
An independent data monitoring committee (DMC) will convene to review safety and efficacy 
data after approximately the first 50% of participants enrolled have completed their Week 12 
visit or prematurely discontinued from the study drug. 
A futility assessment will be conducted based on the proportion of participants with HIV-1 
RNA ≥ 50 copies/mL at Week 12 by the FDA-defined snapshot algorithm. If the lower bound 
of 95% CI of treatment difference [Treatment Group 1–Treatment Group 3] is > 0, the DMC 
may recommend discontinuation of Treatment Group 1 for futility. The final decision to 
discontinue a treatment group will be made by the sponsor based on the totality of efficacy, 
safety, PK, and other data. 

Lenacapavir, GS-5423, GS-2872
Protocol GS-US-536-5939
Final
Gilead Sciences, Inc. 
Amendment 3
CONFIDENTIAL
Page 15
13 May 2024
In addition, if 4 or more participants in Treatment Group 1 experience confirmed VR before 
all participants reach Week 26, an ad hoc DMC meeting may be convened to assess the data.
Further details will be provided in the DMC charter.

Lenacapavir, GS-5423, GS-2872
Protocol GS-US-536-5939
Final
Gilead Sciences, Inc. 
Amendment 3
CONFIDENTIAL
Page 16
13 May 2024
STUDY SCHEMA
Figure 1.
Study Schema*
*Treatment Group 2 was removed in Amendment 2
DMC = data monitoring committee; IV = intravenous; LEN = lenacapavir; Q6M = every 6 months; SC = subcutaneous 
a
In the treatment extension, participants randomized to Treatment Group 1 will continue to receive the study drugs every 
26 weeks as in their randomized treatment phase. Participants from Treatment Group 3 who enter the extension phase will 
switch to receive LEN, GS-5423, and GS-2872. Participants from Treatment Group 3 will also receive a LEN 600 mg oral 
loading dose at the Week 52 visit. Both participants from Treatment Groups 1 and 3 will receive LEN 927 mg SC, GS-5423 
2550 mg IV and GS-2872 2550 mg IV every 26 weeks.
Week: 
0 
26 
52 
78 
Dosing: • 
• 
• 
• 
Treatment Group 1 
n=50 
o LEN oral load+ 927 mg SC QGM 
o GS-5423 2550 mg+ GS-2872 2550 mg IV QGM 
Treatment extension• 
Screening 
o LEN 927 mg SC QGM 
o GS-5423 2550 mg + GS-2872 2550 mg IV QGM 
n=25 
Treatment Group 3 
o Stay on baseline oral ART 
1' endpoint 
2' endpoint 

Lenacapavir, GS-5423, GS-2872
Protocol GS-US-536-5939
Final
Gilead Sciences, Inc. 
Amendment 3
CONFIDENTIAL
Page 17
13 May 2024
STUDY PROCEDURES TABLE
Table 1.
Study Procedures Table (Treatment Group 1)
Screening
Randomized Phase
Extension Phaseu
Post Study 
Drug Follow-
upc 
Study Procedure
Visit 
1
Visit 
2a
Day 1
Day 2b
Day 8b
Day
15b
Wk 
4
Wk 
12
Wk 
24
Wk 
26
Wk 
38
Wk 
50
Wk 
52
Wk 
64, 
90, 
116, 
142
Wk 
76, 
102, 
128, 
154
Wk 
78, 
104, 
130, 
156
ESDDc
PSD 
Day 
30, 90, 
180
PSD 
Day 
270, 
365
Visit Window 
(Days)
Within 28 
Days of 
Screening 
Visit 2
± 3 Days
± 6 Days
± 6 Days
± 6 Days
Written informed 
consent
X
Medical history 
X
X
Review concomitant 
medications
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Review AEs 
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Complete physical 
examination
X
X
X
Focused physical 
examination
X
X
X
X
X
X
X
X
Height 
X
Weight 
X
X
X
X
X
X
X
X
X
X
X
Vital signsd
X
X
X
X
X
X
X
X
X
X
X
Proviral DNA 
phenotype
X
Proviral DNA 
genotype
X

Lenacapavir, GS-5423, GS-2872
Protocol GS-US-536-5939
Final
Gilead Sciences, Inc. 
Amendment 3
CONFIDENTIAL
Page 18
13 May 2024
Screening
Randomized Phase
Extension Phaseu
Post Study 
Drug Follow-
upc 
Study Procedure
Visit 
1
Visit 
2a
Day 1
Day 2b
Day 8b
Day
15b
Wk 
4
Wk 
12
Wk 
24
Wk 
26
Wk 
38
Wk 
50
Wk 
52
Wk 
64, 
90, 
116, 
142
Wk 
76, 
102, 
128, 
154
Wk 
78, 
104, 
130, 
156
ESDDc
PSD 
Day 
30, 90, 
180
PSD 
Day 
270, 
365
Visit Window 
(Days)
Within 28 
Days of 
Screening 
Visit 2
± 3 Days
± 6 Days
± 6 Days
± 6 Days
Chemistrye
X
X
X
X
X
X
X
X
X
X
X
Hematologye
X
X
X
X
X
X
X
X
X
X
X
TSH 
X
X
X
X
CD4+ and CD8+ T-
cell count
X
X
X
X
X
X
X
X
X
Xf
Serum pregnancy 
test
X
FSHg
X
Urinalysis
X
X
X
X
X
X
X
X
X
X
X
Urine pregnancy 
testh
X
X
X
X
X
X
X
X
X
X
X
HBV & HCV 
serology
X
HIV-1 RNA 
X
X
X
X
X
X
X
X
X
X
X
X
X
X
HIV-1 genotype/
phenotypei
 
X
HIV reservoir assay 
(PBMC)j 
X
X
X
X

Lenacapavir, GS-5423, GS-2872
Protocol GS-US-536-5939
Final
Gilead Sciences, Inc. 
Amendment 3
CONFIDENTIAL
Page 19
13 May 2024
Screening
Randomized Phase
Extension Phaseu
Post Study 
Drug Follow-
upc 
Study Procedure
Visit 
1
Visit 
2a
Day 1
Day 2b
Day 8b
Day
15b
Wk 
4
Wk 
12
Wk 
24
Wk 
26
Wk 
38
Wk 
50
Wk 
52
Wk 
64, 
90, 
116, 
142
Wk 
76, 
102, 
128, 
154
Wk 
78, 
104, 
130, 
156
ESDDc
PSD 
Day 
30, 90, 
180
PSD 
Day 
270, 
365
Visit Window 
(Days)
Within 28 
Days of 
Screening 
Visit 2
± 3 Days
± 6 Days
± 6 Days
± 6 Days
eGFR
X
X
X
X
X
X
X
X
X
X
X
ECGj
X
X
X
X
X
Plasma storage 
samples for virology 
testing
X
X
X
X
X
X
X
X
X
X
X
X
Immunogenicity 
(ADA) serum 
samplel
X
X
X
X
X
X
X
X
X
X
X
Serum PK samples 
(GS-5423 & 
GS-2872)m, n
X
X
X
X
X
X
X
X
X
X
X
X
X
Plasma PK sample 
for LENm, o 
X
X
X
X
X
X
X
X
X
X
X
X
X
CCI
CCI
-----------------------------------------------------------------------------

Lenacapavir, GS-5423, GS-2872
Protocol GS-US-536-5939
Final
Gilead Sciences, Inc. 
Amendment 3
CONFIDENTIAL
Page 20
13 May 2024
Screening
Randomized Phase
Extension Phaseu
Post Study 
Drug Follow-
upc 
Study Procedure
Visit 
1
Visit 
2a
Day 1
Day 2b
Day 8b
Day
15b
Wk 
4
Wk 
12
Wk 
24
Wk 
26
Wk 
38
Wk 
50
Wk 
52
Wk 
64, 
90, 
116, 
142
Wk 
76, 
102, 
128, 
154
Wk 
78, 
104, 
130, 
156
ESDDc
PSD 
Day 
30, 90, 
180
PSD 
Day 
270, 
365
Visit Window 
(Days)
Within 28 
Days of 
Screening 
Visit 2
± 3 Days
± 6 Days
± 6 Days
± 6 Days
Randomization
X
HIV Treatment 
Preference 
Questionnaire
X
X
X
X
HIVDQoL
X
X
X
X
HIVTSQsq
X
X
X
X
X
HIVTSQcq
X
LEN oral 
administrationr
X
X
LEN SC 
administration
X
X
X
X
GS-5423 IV infusion 
administrations
X
X
X
X
GS-2872 IV infusion 
administrations
X
X
X
X
CCI
CCI

Lenacapavir, GS-5423, GS-2872 
Protocol GS-US-536-5939 
Gilead Sciences, Inc. 
Final 
Amendment3 
ADA = antidmg antibody; AE = adverse event; ARV = antiretroviral; bNAb = broadly neutralizing antibody; CD4 = clusters of differentiation 4; CD8 = clusters of 
differentiation 8; DNA = deoxyribonucleic acid; ECG = electrocardiogram; eGFR = estimated glomemlar filtration rate; ESDD = early study dmg discontinuation; ET = early 
tennination; FSH = follicle-stimulating ho,mone; Gilead = Gilead Sciences; HBV = hepatitis B virus; HCV = hepatitis C vims; HIV = human immunodeficiency vims; HIV-
1 = human immunodeficiency vims type 1; HIVDQoL = HIV-dependent quality of life; HIVTSQc = HIV Treatment Satisfaction Questionnaire change version; HIVTSQs = HIV 
Treatment Satisfaction Questionnaire status version; IV = intravenous; LEN = lenacapavir; PBMC = peripheral blood mononuclear cell; PK = pha,macokinetic(s); PSD = post 
study diug; RNA = ribonucleic acid; SC = subcutaneous; TSH = thyroid-stimulating hormone; Wk = week 
Scre.ening Visit 2 will be erformed once results of GS-5423 and GS-2872 sensitivi testino from Visit 1 are reviewed and participant is deemed eligible to proceed. 
Re er to Section 6.3 .11 or ESDD an post-ESDD 30-, 90-, 180-, 270-, an 365- ay o ow-up visits. Counsel pa,ticipant regarding the importance of continuing a complete 
ARV therapy in accordance to standard of care, and refer participant to an appropriate HIV treatiuent facility. 
d 
Vital signs: blood pressure, pulse, and temperattu·e. On dosing days for LEN + GS-5423 + GS-2872, vital signs should be recorded prior to sta,t of stlldy dmg administration 
and 30 minutes (± 10 minutes) after completion of both GS-5423 and GS-2872 infusion, if coadministered or the GS-2872 infusion, if sequentially administered. 
e 
Refer to Table 6 for specific tests that are not on a standard chemistry panel ( eg, amylase/lipase, uric acid). 
f 
CD4+ and CD8+ T-cell counts at post-ESDD 90-day follow-up visit only. 
g 
An FSH test is required for pa,ticipants assigned female at biith who are younger than 54 years, have not undergone permanent sterilization, are not on hormonal 
conti·aception, and have stopped menstmating for at least 12 months but do not have docmnentation of ovarian honuonal failllle; see Appendix 11.3. 
h 
Pa,ticipants assigned female at biith of childbearing potential only. On dosing days, mine pregnancy test to be performed predose. A positive mine pregnancy test should be 
confomed with a senun pregnancy test. 
HIV-1 genotype and phenotype testing for pa,ticipants with confomed virologic failm·e and HIV-1 RNA:::: 200 copies/nll,. Refer to Section 6.3.9.2. 
HIV reservoir sample (PBMC) and ECG to be collected at Day 1, Week 26, Week 52, Week 104, and every 12 months thereafter. 
n 
Senun PK samples for GS-5423 and GS-2872 will be collected in all pa,ticipants as follows: 
• 
Day 1: 0 hollls (predose, 30 minutes prior to dosing of oral LEN) and within 5 minutes after the end of the second antibody infusion (GS-2872). 
• 
Week 26: 0 hollls (predose, 30 minutes prior to dosing of SC LEN) and within 5 minutes after the end of the second antibody infusion (GS-2872). 
• 
Week 52 and subsequent dosing days: 0 hollls (predose, 30 minutes prior to dosing of SC LEN) and within 5 minutes after the end of both antibody infusions (GS-5423 
and GS-2872), if coadininistered or the second antibody infusion (GS-2872), if sequentially adininistered. 
• 
A single any time sample at other scheduled visits. 
o 
Plasma samples for LEN will be collected in all participants as follows: 
• 
Day 1: 0 hollls (predose, 30 minutes prior to dosing of oral LEN) and within 5 minutes after the end of the second antibody infusion (GS-2872). 
• 
Week 26 and subsequent dosing days: 0 hollls (predose, 30 minutes prior to dosing of SC LEN). 
A sin le an time sam le at other scheduled visits. 
I' 
CONFIDENTIAL 
Page 21 
13 May 2024 

Lenacapavir, GS-5423, GS-2872
Protocol GS-US-536-5939
Final
Gilead Sciences, Inc. 
Amendment 3
CONFIDENTIAL
Page 22
13 May 2024
q
On visits when both HIVTSQs and HIVTSQc will be completed, HIVTSQs should be completed first.
r
Participants will take 2 oral LEN tablets on Day 1 at the clinic and self-administer 2 oral LEN tablets on Day 2 at home,
s
Refer to Section 5.3. If coadministered, infusion of GS-5423 and GS-2872 will begin immediately following (up to 1 hour after) the last SC LEN injection. If sequentially 
administered, infusion of GS-2872 will begin at least 15 minutes following (up to 1 hour after) the completion of GS-5423 IV infusion. The exact date and time of study drug 
administration must be carefully recorded. Participants will remain in a monitored clinical setting for at least 30 minutes after completion of GS-5423 and GS-2872 infusion, 
if coadministered or GS-2872 infusion if sequentially administered. For the Day 1 and Week 26 visits and all subsequent dosing visits, all study drugs are to be administered 
on the same day.
u
Participants may opt to continue study visits beyond Week 156 on the same schedule with study visits every 12 and 24 weeks between dosing visits (every 26 weeks) until the 
product becomes accessible to participants through an access program, is commercially available, or Gilead elects to discontinue the study, whichever occurs first.
CCI
CCI
CCI

Lenacapavir, GS-5423, GS-2872
Protocol GS-US-536-5939
Final
Gilead Sciences, Inc. 
Amendment 3
CONFIDENTIAL
Page 23
13 May 2024
Table 2.
Study Procedures Table (Treatment Group 3)
Screening
Randomized Phase
Extension Phases
ESDDb
Post Study Drug 
Follow-upcb
Study Procedure
Visit 1
Visit 
2a
Day 1
Wk 
12
Wk 
26
Wk 
38
Wk 
50
Wk 
52
Wk 
56
Wk 
64, 
90, 
116, 
142
Wk 
76, 
102, 
128, 
154
Wk 
78, 
104, 
130, 
156
PSD 
Day 
30, 90, 
180
PSD 
Day 
270, 
365
Visit Window (Days)
Within 28 
Days of 
Screening 
Visit 2
± 6 Days
± 6 Days
± 6 Days
Written informed consent
X
Medical history 
X
X
Review concomitant medications
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Review AEs 
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Complete physical examination
X
X
X
Focused physical examination
X
X
X
X
X
X
X
X
Height 
X
Weight 
X
X
X
X
X
X
X
X
X
X
X
Vital signsc
X
X
X
X
X
X
X
X
X
X
X
Proviral DNA phenotype
X
Proviral DNA genotype
X
Chemistryd
X
X
X
X
X
X
X
X
X
X
X
Hematologyd
X
X
X
X
X
X
X
X
X
X
X
TSH 
X
X
X
X
CD4+ and CD8+ T-cell count
X
X
X
X
X
X
X
X
X
Xe

Lenacapavir, GS-5423, GS-2872
Protocol GS-US-536-5939
Final
Gilead Sciences, Inc. 
Amendment 3
CONFIDENTIAL
Page 24
13 May 2024
Screening
Randomized Phase
Extension Phases
ESDDb
Post Study Drug 
Follow-upcb
Study Procedure
Visit 1
Visit 
2a
Day 1
Wk 
12
Wk 
26
Wk 
38
Wk 
50
Wk 
52
Wk 
56
Wk 
64, 
90, 
116, 
142
Wk 
76, 
102, 
128, 
154
Wk 
78, 
104, 
130, 
156
PSD 
Day 
30, 90, 
180
PSD 
Day 
270, 
365
Visit Window (Days)
Within 28 
Days of 
Screening 
Visit 2
± 6 Days
± 6 Days
± 6 Days
Serum pregnancy test
X
FSHf
X
Urinalysis
X
X
X
X
X
X
X
X
X
X
X
Urine pregnancy testg
X
X
X
X
X
X
X
X
X
HBV & HCV serology
X
HIV-1 RNA 
X
X
X
X
X
X
X
X
X
X
X
X
X
HIV-1 genotype/phenotypeh
 
X
X
HIV reservoir assay (PBMC)i 
X
X
X
X
eGFR
X
X
X
X
X
X
X
X
X
X
X
ECGi
X
X
X
X
X
Plasma storage samples for 
virology testing
X
X
X
X
X
X
X
X
X
X
X
Immunogenicity (ADA) serum 
samplek
X
X
X
X
X
X
Serum PK samples (GS-5423 & 
GS-2872)l, m
X
X
X
X
X
X
X
CCI

Lenacapavir, GS-5423, GS-2872
Protocol GS-US-536-5939
Final
Gilead Sciences, Inc. 
Amendment 3
CONFIDENTIAL
Page 25
13 May 2024
Screening
Randomized Phase
Extension Phases
ESDDb
Post Study Drug 
Follow-upcb
Study Procedure
Visit 1
Visit 
2a
Day 1
Wk 
12
Wk 
26
Wk 
38
Wk 
50
Wk 
52
Wk 
56
Wk 
64, 
90, 
116, 
142
Wk 
76, 
102, 
128, 
154
Wk 
78, 
104, 
130, 
156
PSD 
Day 
30, 90, 
180
PSD 
Day 
270, 
365
Visit Window (Days)
Within 28 
Days of 
Screening 
Visit 2
± 6 Days
± 6 Days
± 6 Days
Plasma PK sample for LENl, n 
X
X
X
X
X
X
X
Randomization
X
HIV Treatment Preference 
Questionnaire
X
X
X
X
HIVDQoL
X
X
X
X
HIVTSQso
X
X
X
X
X
HIVTSQco
X
Continue baseline oral ART
X
LEN oral administrationp
X
LEN SC administration
X
X
GS-5423 IV infusion 
administrationq
X
X
GS-2872 IV infusion 
administrationq
X
X
CCI

Lenacapavir, GS-5423, GS-2872 
Protocol GS-US-536-5939 
Gilead Sciences, Inc. 
ADA = antidmg antibody; AE = adverse event; ARV = antiretroviral; bNAb = broadly neutralizing antibody; CD4 = clusters of differentiation 4; CD8 = clusters of 
differentiation 8; DNA = deoxyribonucleic acid; ECG = electrocardiogram; eGFR = estimated glomemlar filtration rate; ESDD = early study dmg discontinuation; 
Final 
Amendment3 
FSH = follicle-stimulating honuone; Gilead = Gilead Sciences; HBV = hepatitis B vims; HCV = hepatitis C vims; HIV = human immunodeficiency vims; HIV-1 = human 
immunodeficiency vims type 1; HIVDQoL = HIV-dependent quality of life; HIVTSQc = HIV Treatment Satisfaction Questionnaire change version; 
HIVTSQs = HIV Treatment Satisfaction Questionnaire status version; IV = intravenous; LEN = lenacapavir; PBMC = peripheral blood mononuclear cell; 
PK = pha1macokinetic{s); PSD = post study dtug; RNA = ribonucleic acid; SC = subcutaneous; TSH = thyroid-stimulating honuone; Wk = week 
a 
Screening Visit 2 will be performed once results of GS-5423 and GS-2872 sensitivity testing from Visit 1 are reviewed and participant is deemed eligible to proceed. 
b 
For participants who discontinue the study prior to Week 52, only a ESDD and 30-day follow-up visit is required. For participants who receive study dtug in extension phase, 
refer to Section 6.3 .11 for ESDD and post-ESDD 30-, 90-, 180-, 270-, and 365-day follow-up visits. Counsel pa1t icipant regarding the importance of continuing a complete 
ARV therapy in accordance to standard of care, and refer participant to an appropriate HIV treatment facility. 
c 
Vital signs: blood pressure, pulse, and temperattu·e. On dosing days for LEN + GS-5423 + GS-2872, vital signs should be recorded prior to sta1t of stlldy dmg administration 
and 30 minutes (± 10 minutes) after completion of both GS-5423 and GS-2872 infusion, if coadministered or the GS-2872 infusion, if sequentially administered. 
d 
Refer to Table 6 for specific tests that are not on a standard chemistry panel ( eg, amylase/lipase, uric acid). 
e 
CD4+ and CD8+ T-cell count at post-ESDD 90-day follow-up visit only. 
f 
An FSH test is required for pa1t icipants assigned female at birth who are younger than 54 years, have not undergone permanent sterilization, are not on hormonal 
contraception, and have stopped menstmating for at least 12 months but do not have documentation of ovarian honuonal failllle; see Appendix 11.3. 
g 
Pa1t icipants assigned female at birth of childbearing potential only. On Week 52 and subsequent dosing days, urine pregnancy test to be performed predose. During the 
randomized and extension phase, a positive urine pregnancy test should be confinued with a senun pregnancy test. 
h 
HIV-1 genotype and phenotype testing for pa1t icipants with confomed virologic failure and HIV-1 RNA:::: 200 copies/mL. Refer to Section 6.3.9.2. 
HIV reservoir sam le PBMC and ECG to be collected at Da 1, Week 26, Week 52, Week 78, Week 104, and eve1 12 months thereafter. 
On osmg ays, ADA samp es must e co ecte pre ose. 
The exact date and time of collection of PK samples must be recorded. PK samples should be dt·awn from a separate catheter in the opposite anu from the one used for 
GS-5423 and GS-2872 IV infusions to avoid contantination. Refer to Section 6.3.6 for details. 
m 
Senun PK samples for GS-5423 and GS-2872 will be collected in all pa1t icipants as follows: 
• 
Week 52: 0 hollls (predose, 30 minutes prior to dosing of oral LEN) and within 5 minutes after the end of both antibody infusions (GS-5423 and GS-2872), if 
coadtninistered or the second antibody infusion (GS-2872), if sequentially adtninistered. 
• 
Week 78 and subsequent dosing visits: 0 hollls (predose, 30 minutes prior to dosing of SC LEN). 
• 
A single any time sample at other scheduled visits. 
n 
Plasma PK samples for LEN will be collected in all pa1t icipants as follows: 
• 
Week 52: 0 hollls (predose, 30 minutes prior to dosing of oral LEN) and within 5 minutes after the end of the infusion of both antibodies (GS-5423 and GS-2872), if 
coadtninistered or the second antibody infusion (GS-2872), if sequentially adtninistered. 
• 
Week 78 and subsequent dosing days: 0 hollls (predose, 30 minutes prior to dosing of SC LEN). 
A sin le an time sam le at other scheduled visits. 
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q
Refer to Section 5.3. If coadministered, infusion of GS-5423 and GS-2872 will begin at least 15 minutes (up to 1 hour after) after SC LEN injection. If sequentially 
administered, infusion of GS-2872 will begin at least 15 minutes following (up to 1 hour after) the completion of GS-5423 IV infusion. The exact date and time of study drug 
administration must be carefully recorded. Participants will remain in a monitored clinical setting for at least 30 minutes after completion of GS-5423 and GS-2872 infusion, 
if coadministered or GS-2872 infusion, if sequentially administered. For the Week 52, 78, and 104 visits and all subsequent dosing visits, all study drugs are to be 
administered on the same day. 
s
Participants may opt to continue study visits beyond Week 156 on the same schedule with study visits every 12 and 24 weeks between dosing visits (every 26 weeks) until the 
product becomes accessible to participants through an access program, is commercially available, or Gilead elects to discontinue the study, whichever occurs first.
CCI

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1.
INTRODUCTION
1.1.
Background
Human immunodeficiency virus type 1 (HIV-1) infection causes a serious life-threatening 
disease and remains one of the leading causes of morbidity and mortality worldwide. In the 
United States (US), there are approximately 1 million people with HIV-1 (PWH) infection, and 
globally there are over 39 million {UNAIDS Joint United Nations Programme on HIV/AIDS 
2023}. Advances in antiretroviral (ARV) therapy (ART) for HIV have led to significant 
improvements in morbidity and mortality by suppressing viral replication, preserving 
immunologic function, and averting disease progression to AIDS. However, current therapeutic 
strategies have been unable to eliminate the virus and cure HIV-1 infection.
While current combination ART for the treatment of HIV-1 infection is efficacious and 
well-tolerated, these agents need to be taken every day and require near-perfect adherence to 
minimize the emergence of drug-resistant variants. As a result, “treatment fatigue” can occur, 
defined as “decreased desire and motivation to maintain vigilance in adhering to a treatment 
regimen” among patients prescribed chronic or lifelong treatment {Claborn 2015}, which can 
lead to nonadherence and treatment failure. As such, there remains a significant medical need for 
ARVs that can be administered less frequently (ie, long-acting drug products), thereby providing 
an alternative treatment option for PWH. Identifying multiple ARVs with comparable dosing 
windows which can be combined in a regimen continues to pose a challenge in developing 
long-acting HIV treatment options.
Lenacapavir (LEN, Sunlenca®), which is administered subcutaneously once every 6 months, has 
the potential to address this unmet need, with suitable long-acting partner agents. Lenacapavir is 
a novel, first-in-class, multistage, selective inhibitor of HIV-1 capsid function targeted for the 
treatment of HIV-1 infection. Lenacapavir has potent antiviral activity with no overlapping 
resistance with any approved products. It has a low human clearance and is being developed as a 
long-acting ARV for treatment and for the prevention of HIV-1. 
Monoclonal antibodies (mAbs) with broad, neutralizing activity against HIV-1 envelope 
glycoproteins {Burton 2015} also have the potential to be dosed less frequently and paired with 
other long-acting treatments, thus potentially mitigating the challenges of lifelong adherence to 
daily therapy. Antibodies also engage the immune system which may contribute to a beneficial 
HIV-specific immune response {Niessl 2020}, including the potential clearance of latently 
infected cells {Gaebler 2022}, which is not achieved by ARV drugs. As biologics, broadly 
neutralizing antibodies (bNAbs) may spare PWH from adverse effects associated with chronic 
ART. 
HIV-1, however, is a diverse virus whose variants have varying levels of sensitivity for any 
bNAb. Therefore, any bNAbs identified to date have incomplete breadth when measured for 
their ability to neutralize a diversity of HIV-1 isolates {Nishimura 2017}. 3BNC117 and 
10-1074 are 2 of the most potent bNAbs that have been identified and clinically tested. Their 
combination is predicted to neutralize over 95% of HIV-1 variants {Kong 2015, Mouquet 2012, 

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Scheid 2011}. The parenteral administration of 3BNC117 and 10-1074 produces significant, 
transient reductions in plasma viremia in untreated PWH and maintains virologic suppression in 
virologically suppressed PWH who have received bNAbs at the time ART was interrupted 
{Caskey 2015, Caskey 2017, Gaebler 2022, Mendoza 2018, Sneller 2022}. When participants 
suppressed on ART with virus sensitive to 3BNC117 and 10-1074 discontinued ART and were 
dosed every 3 weeks with 3BNC117 and 10-1074, 9 of 11 (81%) participants maintained 
virologic suppression for a median of 21 weeks while plasma bNAbs concentrations remained 
high. Virologic rebound (VR) occurred when the concentration of one or both antibodies waned. 
Participants with early VR were found to harbor viruses resistant to 1 or both bNAbs at baseline 
when alternative methods were used for sensitivity testing {Mendoza 2018}. In a follow-up 
study, 3BNC117 and 10-1074 were administered together for over 20 weeks in PWH without 
prescreening for bNAb sensitivity and 13 of 17 (76%) maintained virologic suppression for at 
least 20 weeks when off other ART {Bar-On 2018}. In a posthoc analysis, the investigators did 
not find a correlation between outcomes and bNAb sensitivity at baseline. A third study 
demonstrated that 3BNC117 and 10-1074 maintained virologic suppression in 6 of 6 participants 
sensitive to both bNAbs, and observed early VR in a participant with resistance to both bNAbs at 
baseline {Sneller 2022}. The results of these studies provide early evidence for utilizing 
3BNC117 and 10-1074 as components for treatment of HIV-1, though they are inconclusive as 
to the optimal testing method and clinical value of screening for bNAb sensitivity.
3BNC117 and 10-1074 have undergone modifications to increase their half-lives, resulting in 
GS-5423 (3BNC117-LS) and GS-2872 (10-1074-LS), and allow for the maintenance of high 
bNAb concentrations over long durations without changing viral neutralization potency. 
Coadministration of 2 bNAbs has maintained viral suppression in a substantial proportion of 
virologically suppressed PWH (up to 60%-85% across studies) and a combination of LEN, 
GS-5423 and GS-2872 maintained virologic suppression in 90% of participants in the proof of 
concept (POC) Phase 1b Study GS-US-536-5816. Pairing the long-acting bNAbs GS-5423 and 
GS-2872 with the long-acting ARV drug LEN may overcome the limitations of earlier studies 
with bNAbs alone and enable a safe, effective, and robust long-acting treatment option for PWH.
1.2.
Background on Study Interventions
For the purpose of this protocol, study drug will be defined as LEN, GS-5423, GS-2872, and 
baseline oral ART.
1.2.1.
Lenacapavir
1.2.1.1.
General Information
Lenacapavir is a novel, first-in-class, multistage selective inhibitor of HIV-1 capsid function, 
which has potent antiviral activity, low human clearance, and physiochemical properties well 
suited for extended-release parenteral or oral formulations. 

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For further information on LEN, refer to the investigator’s brochure (IB), including information 
on the following: 
•
Nonclinical pharmacokinetics (PK) and in vitro metabolism
•
Nonclinical pharmacology and toxicology
•
Clinical experience
1.2.2.
GS-5423
1.2.2.1.
General Information
GS-5423 is a recombinant, fully human monoclonal antibody (mAb) of the IgG1κ isotype that 
targets the CD4 binding site of HIV-1 glycoprotein 120 and shows neutralization activity against 
> 80% of viral strains. GS-5423 (also known as teropavimab or 3BNC117-LS) is derived from 
3BNC117, differing only by 2 amino acid substitutions in the crystallizable fragment (Fc) 
portion of the antibody, which enhances the antibody binding affinity to the neonatal Fc receptor 
(FcRn), thus prolonging its half-life in vivo. Affinity binding to other Fc receptors remains 
unchanged. These modifications do not alter the antigen-binding fragment (Fab) of the antibody 
and therefore do not alter its interaction with antigen or safety profile. GS-5423 is a bNAb with 
potent antiviral activity and extended half-life that make it well suited for use as a long-acting 
parenteral ARV. GS-5423 has been characterized in nonclinical and clinical studies.
For further information on GS-5423, refer to the IB, including information on the following: 
•
Nonclinical PK and in vitro metabolism 
•
Nonclinical pharmacology and toxicology
•
Clinical experience
1.2.3.
GS-2872
1.2.3.1.
General Information
GS-2872 is a recombinant, fully human mAb of the IgG1λ isotype that specifically binds to the 
base of the V3 loop within the HIV-1 external membrane glycoprotein, gp120 and shows 
neutralization activity against 61% of viral strains. GS-2872 (also known as zinlirvimab or 
10-1074-LS) and the original antibody from which it is derived, 10-1074, differ only by 2 amino 
acid substitutions in the Fc portion of the antibody, which enhances the antibody binding affinity 
to the FcRn, thus prolonging its half-life in vivo. Affinity binding to other Fc receptors remains 
unchanged. These modifications do not alter the Fab region of the antibody and therefore do not 
alter its interaction with antigen or safety profile. GS-2872 is a bNAb with potent antiviral 
activity and extended half-life that make it well suited for use as a long-acting parenteral ARV. 
GS-2872 has been characterized in nonclinical and clinical studies. 

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For further information on GS-2872, refer to the IB, including information on the following: 
•
Nonclinical PK and in vitro metabolism 
•
Nonclinical pharmacology and toxicology 
•
Clinical experience
1.2.4.
Clinical Studies of Lenacapavir With GS-5423 and GS-2872
GS-US-536-5816 is a randomized, blinded, proof of concept Phase 1b study to evaluate the 
safety and efficacy of a single dose each of a long-acting regimen of LEN, GS-5423, and 
GS-2872 in adults with HIV-1 infection who are virologically suppressed (HIV-1 RNA 
< 50 copies/mL) on oral ART.
The primary cohort included eligible adults with HIV-1, no history of virologic failure (VF) or 
ARV drug resistance, a CD4+ T-cells nadir ≥ 350 cells/µL, screening CD4+ T-cells count > 500 
and on first-line ART for at least 2 years with demonstrated virologic suppression (HIV-1 RNA 
< 50 copies/mL) for at least 18 months who had sensitivity to both GS-5423 and GS-2872, as 
measured by the PhenoSense monoclonal antibody assay (Monogram Biosciences), were 
randomized in a 1:1 ratio to 2 treatment groups. 
All participants received GS-5423 (30 mg/kg intravenous [IV]) and oral LEN 600 mg Day 1 and 
Day 2 and LEN for subcutaneous (SC) injection 927 mg on Day 1. The 2 randomization arms 
differed only in the dose of GS-2872 that they received (10 mg/kg or 30 mg/kg administered IV).
Participants discontinued their background oral ARV regimen 1 day prior to receiving study 
drugs on Day 1. At Week 26, all participants who remained virologically suppressed, resumed 
their background oral ARV baseline regimen (or compatible regimen selected by the 
investigator) and return to the clinic for visits at Weeks 38 and 52. 
Twenty-one participants were enrolled into the primary cohort and randomized, 20 received the 
complete study drugs (10 in each treatment group), one participant received oral LEN and 
withdrew consent prior to completing dosing procedures. The median age of participants was 
44 years (range: 25 to 61 years), 18 (86%) were male sex at birth; and at baseline, all had HIV-1 
RNA < 50 copies/mL and CD4 count ≥ 500 cells/µL. 
The primary endpoint was the incidence of treatment-emergent serious adverse events (TESAEs) 
through Week 26. There were no TESAEs, no treatment-emergent adverse events (TEAEs) 
leading to discontinuation of study drug or study and no deaths. The most common TEAEs were 
injection site reactions (ISRs) related to administration of SC LEN injection. There was 
1 reported infusion-related reaction that was mild in severity and consisted of pyrexia and 
flushing after GS-2872 infusion which resolved without treatment. There were no clinically 
meaningful treatment-emergent laboratory abnormalities that were Grade 3 or higher. There was 
no observed difference in safety events between the 2 treatment groups. 

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Efficacy was assessed at Week 26 according to the US Food and Drug Administration (FDA) 
snapshot algorithm. At Week 26, 1 of 10 participants (10%) in the GS-2872 10 mg/kg treatment 
group and 0 of 10 participants in the GS-2872 30 mg/kg treatment group had HIV-1 RNA 
≥ 50 copies/mL. Nine of 10 participants (90%) in each group maintained viral suppression with 
HIV-1 RNA < 50 copies/mL at Week 26; 1 participant in the GS-2872 30 mg/kg group had no 
virologic data in the Week 26 window, their last on-study HIV-1 RNA was < 50 copies/mL. 
The mean (SD) CD4 cell counts at baseline were as follows: GS-2872 10 mg/kg group 
903 (303.7) cells/μL; GS-2872 30 mg/kg group 1086 (333.6) cells/μL. The CD4+ T-cell count 
was maintained at Week 26 for both treatment groups. 
For complete study details for the primary cohort, please refer to the IBs for GS-5423 and 
GS-2872. 
Study GS-US-536-5816 also included a pilot cohort of participants who met sensitivity criteria 
for either GS-5423 or GS-2872 but not both; the other inclusion and exclusion criteria were 
identical to the primary cohort. Pilot cohort participants were randomized in a 1:1 ratio to the 
same 2 dosing groups as the primary cohort; randomization was stratified by the sensitivity to 
GS-5423 or GS-2872. 
Eleven participants were enrolled into the pilot cohort and received the complete study drugs 
(5 in the GS-2872 10 mg/kg group and 6 in the GS-2872 30 mg/kg group). One participant 
restarted ART on Day 30 due to a protocol violation (chronic hepatis B infection) and continued 
on study; they are included in the safety analyses but excluded from the efficacy analyses. The 
median age of participants was 49 years (range: 28 to 63); 8 participants (73%) were assigned 
male at birth; and all had HIV-1 RNA < 50 copies/mL; and at baseline, all except 1 participant 
had CD4 cell count ≥ 500 cells/µL. 
The primary endpoint was the incidence of TESAEs through Week 26. There was 1 TESAE and 
no Grade 2 or higher AEs related to study drug. There were no TEAEs leading to discontinuation 
of study drug or study and no deaths. There was 1 TESAE of soft-tissue infection, which was not 
related to study drug or procedures. The most common TEAEs were ISRs related to 
administration of SC LEN injections. There were no infusion-related reactions and no treatment-
emergent laboratory abnormalities that were Grade 3 or 4. There was no observed difference in 
safety events between the 2 treatment groups. 
Efficacy was assessed at Week 26 according to the US FDA snapshot algorithm. At Week 26, 
2 of 4 participants (50%) in the GS-2872 10 mg/kg treatment group and 0 of 6 participants in the 
GS-2872 30 mg/kg treatment group had HIV-1 RNA ≥ 50 copies/mL. The 2 participants had 
VRwith HIV-1 RNA of 72 and 55 copies/mL respectively at Week 26; neither met the criteria 
for confirmed virologic failure (HIV-1 RNA ≥ 200 copies/mL on consecutive tests). 
The mean (SD) CD4 cell counts at baseline were as follows: GS-2872 10 mg/kg group 
1017 (628.7) cells/μL; GS-2872 30 mg/kg group 957 (189.1) cells/μL. The CD4+ T-cell count 
was maintained at Week 26 for both treatment groups.

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1.3.
Rationale for This Study
A combination of 2 potent bNAbs can control viral replication or maintain viral suppression in 
the absence of ART in PWH {Gaebler 2022, Mendoza 2018, Sneller 2022} though uncertainty 
remains on how to best identify people with sensitive viruses clinically. Some participants of 
clinical trials who received 2 bNAbs alone did not respond and had early VR, others rebounded 
when the serum antibody concentrations waned. In Study GS-US-536-5816, the bNAbs GS-5423 
and GS-2872 were combined with LEN to improve the breadth and increase the barrier to 
resistance and durability of the study drugs. As detailed above, virologically suppressed PWH 
who had sensitivity to both bNAbs were enrolled, and 19 of 20 participants who received the 
complete study regimen maintained virologic suppression while on study drug through Week 26 
or their last study visit. The combination regimen was safe and well tolerated.
The proposed Study GS-US-536-5939 builds directly on the findings of Study GS-US-536-5816. 
The study is open label to facilitate comparison of the study drugs, dosed parenterally every 
6 months, to the standard of care regimen given as an oral pill(s) daily. The primary efficacy 
endpoint (HIV-1 RNA ≥ 50 copies/mL) at Week 26 is set forth in guidance from the US FDA for 
Phase 2 studies in a virologically suppressed population. Participants will be treated in their 
randomized groups until secondary outcomes for safety and efficacy at Week 52 to gather data 
through multiple dosing intervals of the study drugs. 
Prior data suggests that engagement of the host immune system by bNAbs may contribute to 
enhanced HIV specific immune responses, control of HIV-1 replication even after neutralizing 
antibody concentrations decline and facilitate the clearance of latently infected cells, thus 
reducing an individual’s HIV latent reservoir {Lu 2016}. Because GS-5423 and GS-2872 are 
human antibodies targeting viral antigens, chronic use may not be associated with a risk for 
toxicities that accompanies the use of most small molecule ARVs. 
Developing safe and effective therapeutic options that maintain virologic suppression and 
facilitate adherence over a lifetime of therapy for PWH remains a priority. For many individuals, 
including some who struggle with daily oral pills, newer study drugs are needed to control viral 
replication, preserve immune function, and prevent clinical progression. In all PWH, the ideal 
goal of therapy remains complete and durable viral suppression. This Phase 2 study will build on 
the preliminary data demonstrating the efficacy and safety of a regimen consisting of LEN, 
GS-5423, and GS-2872 for the treatment of virologically suppressed PWH.
1.4.
Rationale for Dose Selection
1.4.1.
GS-5423 and GS-2872
In this study, the participants will receive 2550 mg of both GS-5423 and GS-2872 administered 
IV in combination with LEN every 26 weeks. The dose selection for GS-5423 and GS-2872 in 
this study is supported by data from the ongoing Phase 1b POC Study GS-US-536-5816, the 
first-in-human (FIH) studies of GS-5423 and GS-2872, YCO-0946 (NCT03254277) and 
YCO-0971 (NCT03554408) respectively, and the previously completed Phase 1 studies of the 

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non-LS fo1ms of each antibody, 3BNC117 and 10-1074 {Bar-On 2018, Caskey 2015, Caskey 
2017, Gaebler 2022, Mendoza 2018}. 
The ongoing Phase lb study (GS-US-536-5816) tested GS-5423 at 30 mg/kg and GS-2872 at 
10 or 30 mg/kg, administered IV as a single dose in combination with LEN. In the primaiy 
coho1i of the study, pa1iicipants who are sensitive to both bNAbs were enrolled, whereas in the 
pilot coho1i, paiiicipants who ai·e sensitive to only one of the bNAbs were enrolled. In both 
coho1is, GS-5423 at 30 mg/kg and GS-2872 at both 10 and 30 mg/kg were well tolerated with no 
significant safety findings. 
For the primaiy coho1i: at Week 26, 0 of 10 paiiicipants in the GS-2872 30 mg/kg group and 1 of 
10 paiiicipants (10.0%) in the GS-2872 10 mg/kg treatment group had HIV-1 RNA~ 50 
copies/mL. 
For the pilot cohort: at Week 26, 0 of 6 paiiicipants in the GS-2872 30 mg/kg group and 2 of 
4 paiiicipants (50.0%) in the GS-2872 10 mg/kg treatment group had HIV-1 RNA 
50 copies/mL. 
Pooled efficacy results from both coho1is of the Phase 1 b study showed no VRin 16 paiiicipants 
receiving GS-5423 30 mg/kg and GS-2872 30 mg/kg in combination with LEN; of 
14 paiiicipants receiving GS-5423 30 mg/kg and GS-2872 10 mg/kg in combination with LEN, 
3 paiiicipants had VR(21.4%), 1 from the primaiy coho1i and 2 from the pilot cohort. No 
paiiicipant met the criteria for confmned virologic failure. 
Single doses of GS-5423 and GS-2872 alone and in combination were also shown to be safe and 
well tolerated up to 30 mg/kg in the FIH Studies YCO-0946 and YCO-0971 in healthy 
volunteers and virologically suppressed PWH. 
The antiviral activities of the non-LS fonns of each antibody, 3BNC117 and 10-1074, have been 
studied in multiple Phase 1 studies. In studies in PWH undergoing analytical treatment 
intenuption (MCA-0906 {Mendoza 2018} and MCA-0965 {Gaebler 2022} ), it was observed 
that the virological suppression was generally maintained when sernm concentrations of both 
antibodies were above 10 µg/mL, although the data were limited, as only a single dose level was 
studied for both bNAbs. It is anticipated that GS-5423 and GS-2872 will demonstrate similar 
antiviral activity to the unmodified fo1ms (3BNC117 and 10-1074), at the same concentrations 
based on the location of the amino acid substitutions in the Fe region. 
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Based on the PK simulations, a single IV dose of 2550 mg GS-5423 or 2550 mg GS-2872 is 
anticipated to maintain concentrations above 10 µg/mL in nearly 100% of participants at 
6 months after dosing. 3BNC117 and 10-1074 have also been studied in viremic PWH as 
monotherapy and in combination {Bar-On 2018, Caskey 2015, Caskey 2017}. Correlations 
between serum antibody concentration and viral load reduction at the nadir from these studies 
suggest the antiviral response is saturated at the concentration range corresponding to the 
predicted Ctrough levels maintained with doses of 2550 mg of GS-5423 and 2550 mg of GS-2872 
at Week 26, although the data are limited.
The safety and efficacy results from studies with GS-5423 and GS-2872 taken together with 
PK modeling suggest that 2550 mg flat doses of GS-5423 and GS-2872 are expected to be safe 
and efficacious in combination with LEN to be evaluated in this Phase 2 study in virologically 
suppressed adults with HIV-1 infection.
1.4.2.
Lenacapavir
The LEN doses and formulations to be evaluated in this study are informed by antiviral activity, 
PK, and/or safety data from Phase 1b POC study (GS-US-200-4072), Phase 1 Studies 
GS-US-200-4071, GS-US-200-4538, and GS-US-200-5709, as well as available safety data from 
the ongoing Phase 2/3 clinical studies in heavily treatment-experienced (HTE) and treatment 
naive (TN) PWH (GS-US-200-4625 and GS-US-200-4334, respectively).
In the Phase 1b POC study (GS-US-200-4072), potent antiviral activity of LEN was 
demonstrated in TN and treatment-experienced but capsid inhibitor-naive PWH; the mean 
maximum HIV-1 RNA decline over 10-day monotherapy after single SC doses of 50 to 750 mg 
was 1.8 to 2.3 log10 copies/mL. All participants achieved at least 1 log10 copies/mL decline in 
their HIV-1 RNA at Day 10. Day 10 antiviral activity was comparable across a dose range of 
single doses of 50 to 750 mg. At these doses, mean LEN concentrations on Day 10 were 1.1- to 
20.5-fold higher than the paEC95 for wild type HIV-1 (ie, inhibitory quotient [IQ] = 1.1 to 20.5; 
paEC95 = 3.87 ng/mL in MT-4 cells). Study GS-US-200-4072 demonstrated that near maximal 
(94%) antiviral activity was observed at ≥ 15.5 ng/mL (4-fold higher than the paEC95 from 
MT-4 cells [ie, IQ4]), indicating that substantial increases in antiviral activity with an increase in 
LEN exposure beyond this concentration target are not expected. Based on these data and the 
safety data available to date, the proposed LEN regimen for both treatment groups targets an 
exposure whereby the lower bound of the 90% CI of the Ctrough is at ≥ IQ4 (15.5 ng/mL) starting 
within a few days of dosing initiation, and maintained through Week 26.
Considering this target, a SC LEN regimen (927 mg or 2 × 1.5 mL at 309 mg/mL, administered 
every 26 weeks) preceded by a 14-day oral lead-in is being evaluated in ongoing clinical 
Phase 2/3 studies in HTE and TN PWH (GS-US-200-4625 and GS-US-200-4334). This regimen 
was predicted to achieve target concentrations within a few days of initiation of dosing and 
maintain it throughout the 6-month dosing interval. As clinical data of LEN to date do not raise 
concern for acute safety issues, where an oral lead-in would be beneficial, a simplified LEN 
regimen is being proposed for this study: SC 927 mg LEN injection, 309 mg/mL (2 × 1.5 mL) 
administered on Day 1 along with oral tablet doses of LEN 600 mg (2 × 300 mg) administered 
on Day 1 and Day 2. This will be followed by SC doses of LEN 927 mg administered every 

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26 weeks. The proposed simplified regimen is predicted to achieve target concentrations within a 
few days of dosing initiation with exposures maintained throughout the duration of the 6-month 
dosing interval (Figure 2). This is supported by preliminary PK data available through Day 197 
postdose from Study GS-US-200-5709 (Cohort 2) where the proposed simplified regimen 
demonstrates good agreement between the observed and predicted/simulated data. This 
simplified regimen is being evaluated in ongoing clinical studies for prevention of HIV-1 
(GS-US-528-9023 and GS-US-412-5624).
Figure 2.
Simulated Plasma Profile of LEN Following the Proposed SC LEN 
Regimen Administered Every 26 Weeks With an Oral PK Load on 
Days 1 and 2
CI = confidence interval; IQ4 = inhibitory quotient of 4; IQ6 = inhibitory quotient of 6; LEN = lenacapavir; 
paEC95 = protein-adjusted 95% effective concentration from MT-4 cells (3.87 ng/mL); PK = pharmacokinetic(s); PO = orally; 
Q6MO = every 6 months; SC = subcutaneous
A) 
0 
11--1----------- z:u nglrnl (IQ6J 
8 10 , 
1 
2 
SC 900mg t 
P0 16C10mg t t 
B) 
100 
3 st~ Day 
6 
7 
IJ. 
OP .. 
n 
.A ~ 
= 90% C•I 
15.5 ngiJmL (1'04) 
Iii"'!!"!"------"""'"------. •8..,fold iP ECH(IQ.$) 
i 
i 
~ . 
•••••·• • • .. ·•••• •• ••1•••••• 1•• 
p.aE C.Ss ~IQ4.t 
10- ------- ------
, 
26 
52 
Da,y 1: Si(: 927mg 
Study W.eek 
Day 1: PO 611 mg1 
t · 
f· 
IDoy 2: PO 60 m!;!f,
. ------------
.SC 927mg Q6MO 

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1.5.
Risk/Benefit Assessment for the Study
Potential risks associated with the study include adverse events (AEs), including ISRs with 
SC administration of LEN, infusion-related reactions, and antidrug antibody (ADA)-mediated 
reactions from GS-5423 and GS-2872. Administration of anti–HIV-1 bNAbs, including GS-5423 
and GS-2872, as well as the original bNAbs on which they are based (3BNC117 and 10-1074), 
have been previously evaluated in humans. As observed with other mAbs, anti–HIV-1 bNAbs 
were generally considered safe and well tolerated, and infusion-reactions were more common for 
mAbs that contained murine elements, compared with fully human mAbs like GS-5423 and 
GS-2872. Clinical monitoring for possible immunologic symptoms will be conducted during and 
immediately following bNAb infusion, and study sites are required to have appropriate 
supportive medications available, including, but not limited to, diphenhydramine, 
acetaminophen, and glucocorticoids during IV infusions; and to follow a protocol-specified 
management plan for infusion-related reactions. 
In general, risks include those associated with frequent clinic visits and laboratory blood draws, 
and the associated pain and discomfort of multiple phlebotomies. Strategies to mitigate any 
potential risks include close monitoring of laboratory values as well as AEs. Parameters for 
monitoring of AEs will be well defined and closely followed.
A potential risk of virologic breakthrough with exposure to suboptimal therapeutic 
concentrations of the study drugs or unrecognized preexisting resistance to GS-5423, GS-2872, 
and/or LEN is the possible development of resistance to 1 or more study drugs. Data are limited 
to inform whether the protocol’s application of resistance testing for bNAbs can minimize this 
risk. A low rate of viral rebound was observed in Study GS-US-536-5816, which utilized the 
same sensitivity criteria as will be used in this study, suggesting that the study drugs will provide 
appropriately high efficacy in the study population. Strategies to further mitigate the risk for 
resistance include frequent assessments of HIV-1 RNA to ensure that virologic breakthrough is 
rapidly identified, thus limiting the time during which drug resistance mutations could emerge 
and data monitoring committee (DMC) futility assessments to identify and potentially 
discontinue treatment arms, thereby limiting the number of participants exposed to a treatment 
group that poses a risk to safety or efficacy. Each component of the study drugs is from a novel 
class without any known or predicted cross-resistance with currently approved ART, thus the 
development of resistance to any component of the study drugs would have limited impact on a 
participant’s future treatment options. 
The potential direct benefits of the study include a long-acting regimen that is administered once 
in 6 months rather than daily, thus freeing participants from the requirement of daily adherence 
to ensure efficacy. Participants may benefit from the novel bNAb containing regimen due to 
enhanced engagement of the immune system, reduction of the latent viral reservoir and/or 
improved immunologic control of HIV-1, but the magnitude and clinical importance of these 
potential effects have not been determined. Potential benefits to participants also include the use 
of bNAbs, which may result in reduced risk of end-organ toxicities associated with some ART, 
and the participant’s contribution to understanding the safety and tolerability of a novel 
long-acting treatment strategy including the PK of the regimen and contributions to helping 
develop new classes of ART with potential application for HIV-1 treatment, prevention, and 
cure. 

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An unanticipated event such as a disaster or public health emergency may pose additional 
potential risks to participants such as adequate study drug availability, interruptions to the study 
visit schedule, and adherence to protocol-specified safety monitoring or laboratory assessments. 
Refer to Appendix 11.2 for further details on the risks and risk mitigation strategy.
Considering the above, the benefit-risk balance for this study is considered positive.
1.6.
Compliance
This study will be conducted in compliance with this protocol and in accordance with the ethical 
principles that have their origin in the Declaration of Helsinki and that are consistent with 
International Council for Harmonisation (ICH) Good Clinical Practice (GCP) and applicable 
regulatory requirements.

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2.
OBJECTIVES AND ENDPOINTS
Primary Objective
Primary Endpoint 
•
To evaluate the efficacy of switching to a 
regimen of LEN, GS-5423, and GS-2872 
versus continuing on baseline oral ART as 
determined by the proportion of participants 
with HIV-1 RNA ≥ 50 copies/mL at Week 26
•
Proportion of participants with HIV-1 RNA 
≥ 50 copies/mL at Week 26 as determined by 
the US FDA-defined snapshot algorithm
Secondary Objectives
Secondary Endpoints
•
To evaluate the efficacy of switching to a 
regimen of LEN, GS-5423, and GS-2872 
versus continuing on baseline oral ART as 
determined by the proportion of participants 
with HIV-1 RNA ≥ 50 copies/mL at Week 52
•
To evaluate the efficacy of switching to a 
regimen of LEN, GS-5423, and GS-2872 
versus continuing on baseline oral ART as 
determined by the proportion of participants 
maintaining virologic suppression (HIV-1 
RNA < 50 copies/mL) at Weeks 26 and 52
•
To evaluate CD4+ T-cell counts at Weeks 26 
and 52
•
To evaluate the safety and tolerability of the 
2 treatment groups
•
To evaluate the PK of GS-5423, GS-2872, 
and LEN
•
To evaluate the immunogenicity of GS-5423 
and GS-2872
•
Proportion of participants with HIV-1 RNA 
≥ 50 copies/mL at Week 52 as determined by 
the US FDA-defined snapshot algorithm
•
Proportion of participants with HIV-1 RNA 
< 50 copies/mL at Weeks 26 and 52 as 
determined by the US FDA-defined snapshot 
algorithm
•
Changes from baseline in CD4+ T-cell counts 
at Weeks 26 and 52
•
Proportion of participants experiencing 
TEAEs 
•
Trough concentrations at Weeks 26 and 52 
and PK parameters (AUC0-t, AUClast, t1/2, Cmax, 
and Tmax) for GS-5423, GS-2872, and LEN as 
appropriate
•
Incidence of anti-GS-5423 and anti–GS-2872 
antibodies
CCI

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3.
STUDY DESIGN
3.1.
Study Design Overview
This is a Phase 2, randomized, open-label, active-controlled, multicenter study to evaluate the 
safety and efficacy of the long-acting regimen of LEN, GS-5423, and GS-2872. The study will 
include approximately 75 participants with sensitivity to GS-5423 and GS-2872 by 
protocol-defined criteria, who meet all eligibility criteria, and who will be randomized without 
stratification in a 2:1 ratio to Treatment Groups 1 and 3. Eligible participants have the option of 
participating in a study extension phase after completing study follow-up through Week 52.
3.1.1.
Randomized Phase
Treatment Group 1
Participants in Treatment Group 1 will receive the long-acting regimen consisting of LEN, 
GS-5423, and GS-2872.
Participants will discontinue their baseline oral ART following administration of the complete 
study drugs on Day 1 (SC LEN 927 mg, oral LEN 600 mg, and IV infusions of GS-5423 and 
GS-2872), and will self-administer oral LEN 600 mg at home on Day 2. Participants will also 
receive study drug (SC LEN and IV infusion of GS-5423 and GS-2872) at Week 26. 
All participants in Treatment Group 1 will return to the study center for visits at Weeks 4, 12, 24, 
26, 38, 50, and 52. 
Treatment Group 3
Participants in Treatment Group 3 will continue their baseline oral ART through Week 52. After 
Day 1, participants in Treatment Group 3 will return to the study center for visits at Weeks 12, 
26, 38, 50, and 52.
3.1.2.
Extension Phase
Treatment Group 1
At Week 52, participants in Treatment Group 1 who receive the study drug of LEN, GS-5423, 
GS-2872, and complete the study through Week 52 with HIV-1 RNA < 50 copies/mL at the 
preceding Week 50 visit, will be given the option to participate in the study extension phase. In 
the study extension phase, participants will continue to receive their randomized study drugs 
every 26 weeks.
Participants who elect not to participate or are not eligible to participate in the extension phase 
will resume their baseline oral ART (or appropriate regimen selected by the investigator). 

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Treatment Group 3
Participants in Treatment Group 3 who complete the study through Week 52 with HIV-1 RNA 
< 50 copies/mL at the preceding Week 50 visit and in the absence of confirmed VR (as defined 
in Section 6.3.9.2.2) throughout the randomized phase of the study will be given the option to 
participate in the extension phase and receive the study drugs of LEN, GS-5423, and GS-2872 
every 26 weeks at the dose specified for Treatment Group 1. Treatment with LEN, GS-5423, and 
GS-2872 will start at Week 52 and at that time the baseline oral ART will be discontinued. 
3.2.
Duration of Intervention
Participants who are eligible to participate may receive up to 52 weeks of treatment during the 
randomized phase. Participants who are eligible to participate in the extension phase have the 
option to continue to receive study drug until the product becomes accessible to participants 
through an access program, is commercially available, or Gilead elects to discontinue the study, 
whichever occurs first. 
3.3.
Protocol-Specific Discontinuation Criteria
3.3.1.
Criteria for Early Discontinuation for the Individual Participants
3.3.1.1.
Criteria for Early Discontinuation for the Individual Participant From Study 
Intervention
Study interventions will be discontinued in the following instances:
•
An AE that would, in the judgment of the investigator, affect assessments of clinical 
status to a significant degree. 
o
Following resolution of the AE, the participant may resume study dosing at the 
discretion of the investigator.
•
Unacceptable toxicity, such as a Grade 3 or higher infusion-related reaction to GS-5423 
or GS-2872, per Common Terminology Criteria for Adverse Events (CTCAE) grading 
scale as defined in Section 7.6, or toxicity that, in the judgment of the investigator, 
compromises the ability to continue study-specific procedures or is considered not to be 
in the participant’s best interest.
•
Lack of efficacy: Confirmed VF with emergent resistance to study drugs (refer to 
Section 6.3.9.2). 
•
Participant request to discontinue for any reason.
•
Participant noncompliance.
•
Pregnancy during the study; refer to Appendix 11.3.

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•
Loss to follow-up.
•
Discontinuation of the study by sponsor.
3.3.1.2.
Criteria for Early Discontinuation for the Individual Participant From the Study
The participant will be discontinued from the study early in the following instances:
•
Withdrawal of consent
•
Death
•
Investigator decision to remove participant from the study 
•
Loss to follow-up (see Section 3.3.3) 
•
Discontinuation of study at the request of Gilead
3.3.2.
Criteria for Early Discontinuation of the Study
The study will be discontinued in the following instance:
•
Discontinuation of the study at the request of Gilead, regulatory agency, or an 
institutional review board (IRB).
3.3.3.
Loss to Follow-up
Should the participant fail to return to the investigational site for a scheduled protocol-specific 
visit, sites will need to make at least 2 attempts by a combination of phone and certified mail to 
contact the participant. Sites must document both attempts to contact the participant. If a 
participant is contacted, the participant should be counseled on the importance of maintaining the 
protocol-specified visit scheduled. If a participant does not respond within 4 weeks after the 
second contact, the participant will be considered lost to follow-up and no additional contact will 
be required. 
3.4.
Definitions for Time of Primary Endpoint and End of Study
3.4.1.
Primary Endpoint
The date for the last participant visit for the primary endpoint is the date of the last visit to 
perform assessments for the primary analysis.
3.4.2.
End of Study
The end of this study will be the last participant’s last observation (or visit).

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3.5.
Poststudy Care 
Once a participant has completed their study participation, the long-term care of the participant 
will return to the responsibility of their primary treating physicians.
3.6.
Source Data
The source data for this study will be obtained from participants clinical/hospital records, central 
laboratory, specialty laboratory (eg, for PK/ADA and/or pharmacodynamic data), eCOA, and 
interactive response technology (IRT) data.

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4.
PARTICIPANT POPULATION
4.1.
Number of Participants and Participant Selection
Approximately 75 participants who are sensitive to both GS-5423 and GS-2872 by 
protocol-defined criteria and who meet the eligibility criteria will be randomized without 
stratification in a 2:1 ratio to Treatment Groups 1 and 3.
4.1.1.
Participant Replacement
Participants who discontinue before the end of the study will not be replaced.
4.2.
Inclusion Criteria
Participants must meet all of the following inclusion criteria to be eligible for participation in this 
study:
1) The ability to understand and sign a written informed consent form (ICF), which must be 
obtained prior to initiation of study procedures.
2) Between 18 and 65 years of age, inclusive, at screening.
3) Body weight ≥ 40 kg at Screening Visit 2.
4) On stable oral ART consisting of no more than 2 drug classes (with the exception of 
pharmacologic boosters cobicistat or ritonavir) for ≥ 1 year prior to Screening Visit 2. A 
change in ART regimen ≥ 28 days prior to Screening Visit 2 for reasons other than VF 
(eg, tolerability, simplification, drug-drug interaction profile) is allowed.
5) No clinically significant documented historical resistance to the current ART regimen 
with the exception of isolated nucleoside reverse transcriptase inhibitor mutations 
including M184V or ≤ 2 thymidine analog mutations (TAMs: M41L, D67N, K70R, 
L210W, T215Y, and/or K219Q).
6) Plasma HIV-1 RNA < 50 copies/mL at Screening Visit 2.
7) Documented plasma HIV-1 RNA < 50 copies/mL for ≥ 12 months preceding Screening 
Visit 2 (or undetectable HIV-1 RNA level according to the local assay being used if the 
limit of detection is ≥ 50 copies/mL). Virologic elevations of ≥ 50 copies/mL (transient 
detectable viremia or “blips”) prior to screening are acceptable.
A) If HIV-1 sensitivity testing results are from > 12 months prior to screening (Inclusion 
Criterion 8), then documented plasma HIV-1 RNA < 50 copies/mL encompassing the 
time from sensitivity testing will be required.

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8) HIV-1 sensitivity results from screening or from the Study GS-US-536-5816 within 
36 months prior to Screening Visit 2 meeting specific criteria:
A) Proviral phenotypic sensitivity to both GS-5423 and GS-2872 by the PhenoSense 
Assay (Monogram Biosciences). GS-5423 phenotypic sensitivity is defined as 
90% inhibitory concentration (IC90) ≤ 2 µg/mL; GS-2872 phenotypic sensitivity is 
defined as IC90 ≤ 2 µg/mL.
9) CD4+ T-cell count ≥ 200 cells/µL at Screening Visit 2.
10) Availability of a fully active alternative ART regimen, in the opinion of the investigator, 
in the event of discontinuation of the current ART regimen with development of 
resistance.
11) Estimated glomerular filtration rate (eGFR) ≥ 30 mL/min according to the Modification 
of Diet in Renal Disease formula {Lacombe 2008, Levey 2006}.
12) All of the following laboratory results at Screening Visit 2:
A) Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 5  upper 
limit of normal (ULN).
B) Total bilirubin ≤ 1.5 mg/dL, or normal direct bilirubin.
C) Absolute neutrophil count ≥ 750/mm3; (chronic neutropenia with no clinical 
significance can enroll at investigator discretion).
D) Platelets ≥ 50,000/mm3; and hemoglobin ≥ 8.5 g/dL.
13) Participants assigned female at birth of childbearing potential (as defined in 
Appendix 11.3) must have a negative serum pregnancy test at Screening Visit 2 and 
negative urine pregnancy test at Day 1 prior to study drug administration.
14) Participants assigned female at birth of childbearing potential who engage in heterosexual 
intercourse must agree to utilize protocol-specified method(s) of contraception as 
described in Appendix 11.3.

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4.3.
Exclusion Criteria
Participants who meet any of the following exclusion criteria are not eligible to be enrolled in 
this study:
1) Any prior receipt of LEN or a bNAb for HIV-1 treatment.
2) Receipt of long-acting injectable ARV within 6 months of Screening Visit 2.
3) Have been treated with immunosuppressant therapies or chemotherapeutic agents 
(eg, corticosteroids, immunoglobulins, and other immune- or cytokine-based therapies) 
within 4 weeks of Screening Visit 2 (with the exception of a single short course of 
corticosteroids lasting ≤ 7 days) or have a comorbid condition with an anticipated need 
ongoing immunosuppressive treatment during the study.
4) Pregnant participants assigned female at birth or plans to become pregnant during the 
course of the study.
5) Lactating participants assigned female at birth.
6) Participation in any other clinical study, including observational studies, without prior 
approval from the sponsor.
7) Clinically significant abnormal electrocardiogram (ECG) at the Screening Visit 2.
8) Hepatitis C virus (HCV) antibody positive and HCV RNA detectable.
9) Chronic hepatitis B virus (HBV) infection, as determined by either: positive HBV surface 
antigen and negative HBV surface antibody, regardless of HBV core antibody status, at 
the screening visit, or positive HBV core antibody, negative HBV surface antibody 
regardless of HBV surface antigen status, at Screening Visit 2.
10) Active, serious infections (other than HIV-1 infection) requiring systemic antibiotic or 
antifungal therapy within 30 days prior to Screening Visit 2.
11) Have poor venous access that would limit phlebotomy or IV infusion of study drugs.
12) Have a history of any of the following:
A) Opportunistic infection or illness indicative of Stage 3 HIV disease. 
B) Known hypersensitivity to the study drug, the metabolites, or formulation excipient.

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C) Malignancy within the past 5 years (prior to screening) or ongoing malignancy, other 
than basal cell carcinoma, or resected, noninvasive cutaneous squamous carcinoma.
D) Substance abuse or a psychiatric or medical condition that could, in the opinion of the 
investigator, compromise the participant’s ability to participate in the study.

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5.
STUDY INTERVENTIONS AND CONCOMITANT 
MEDICATIONS 
5.1.
Randomization 
5.1.1.
Randomization
Participants will be assigned a screening number in the IRT system at the time of consent.
Randomization and Day 1 visits must not occur until participant eligibility has been confirmed. 
Once eligibility has been confirmed, the investigator or designee will randomize the participant 
using the IRT system. Once a participant number has been assigned to a participant, it will not be 
reassigned to any other participants. The participant number assignment and randomization may 
be performed up to 3 days prior to Day 1 visit provided all screening procedures have been 
completed and participant eligibility criteria has been confirmed.
Participants who meet eligibility criteria will be randomized in a 2:1 ratio to Treatment Groups 1 
and 3.
5.1.2.
Blinding
Blinding of treatment assignments or data will not be performed in this study.
5.2.
Description and Handling of Lenacapavir, GS-5423, and GS-2872 
5.2.1.
Formulation
5.2.1.1.
Lenacapavir
Lenacapavir tablets, 300 mg, are capsule-shaped, film-coated beige tablets, debossed with “GSI” 
on one side of the tablet and “62L” on the other side of the tablet. Each tablet core contains the 
equivalent of 300 mg LEN free acid in the form of LEN sodium salt. In addition to the active 
ingredient, LEN tablets, 300 mg, contain the following inactive ingredients: microcrystalline 
cellulose, mannitol, poloxamer 407, copovidone, croscarmellose sodium, magnesium stearate, 
polyethylene glycol, polyvinyl alcohol, talc, titanium dioxide, iron oxide red, iron oxide black, 
and iron oxide yellow.
Lenacapavir injection, 309 mg/mL, is a clear, yellow to brown solution for SC injection. 
In addition to the active ingredient (LEN sodium), LEN injection, 309 mg/mL, contains the 
following inactive ingredients: polyethylene glycol 300 and water for injection.
5.2.1.2.
GS-5423
GS-5423 solution for infusion, 150 mg/mL, 1 mL/vial, or 2 mL/vial drug product will be 
supplied as a sterile, preservative-free, colorless to brownish yellow solution for 
IV administration. The drug product is composed of 150 mg/mL GS-5423 in histidine, acetate, 
trehalose, methionine, and polysorbate 20.

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5.2.1.3.
GS-2872
GS-2872 solution for infusion, 150 mg/mL, 1 mL/vial, or 2 mL/vial drug product will be 
supplied as a sterile, preservative-free, colorless to brownish yellow solution for 
IV administration. The drug product is composed of 150 mg/mL GS-2872 in histidine, acetate, 
trehalose, methionine, and polysorbate 20.
5.2.2.
Packaging and Labeling
5.2.2.1.
Lenacapavir
Lenacapavir tablets, 300 mg, are packaged in white, high-density polyethylene bottles. 
Each bottle contains either 4 or 5 tablets, silica gel desiccant, and polyester packing material. 
Each bottle is enclosed with a white, continuous thread, child-resistant polypropylene screw cap 
fitted with an induction-sealed, and aluminum-faced liner.
Lenacapavir injection, 309 mg/mL, is supplied as a sterile solution packaged in a single-use clear 
vial fitted with a rubber stopper and an aluminum flip-off seal.
5.2.2.2.
GS-5423
GS-5423 solution for infusion, 150 mg/mL, 1 mL/vial, or 2 mL/vial drug product is supplied as 
single-use 2R, Type I clear glass vials, with coated elastomeric stoppers, capped with 
polypropylene flip-off caps with aluminum overseals.
5.2.2.3.
GS-2872
GS-2872 solution for infusion, 150 mg/mL, 1 mL/vial, or 2 mL/vial drug product is supplied as 
single-use 2R, Type I clear glass vials, with coated elastomeric stoppers, capped with 
polypropylene flip-off caps with aluminum overseals.
Study drugs to be distributed to centers in the US shall be labeled to meet applicable 
requirements of the US FDA and/or other local regulations.
5.2.3.
Storage and Handling
Until administration and dispensation to the participants, all study drugs should be stored in a 
securely locked area, accessible only to authorized site personnel. To ensure the stability and 
proper identification, study drugs should not be stored in a container other than the container in 
which they were supplied. Consideration should be given to handling, preparation, and disposal 
through measures that minimize drug contact with the body. Appropriate precautions should be 
followed to avoid direct eye contact or exposure when handling.

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5.2.3.1.
Lenacapavir
Lenacapavir tablets, 300 mg, should be stored below 30 °C (86 °F). Storage conditions are 
specified on the study drug label. 
Lenacapavir injection, 309 mg/mL should be stored below 30 °C (86 °F) and protected from 
light. Storage conditions are specified on the study drug label.
5.2.3.2.
GS-5423
GS-5423 solution for infusion, 150 mg/mL, 1 mL/vial, or 2 mL/vial drug product, should be 
stored at 2 °C to 8 °C and protected from light. Storage conditions are specified on the study 
drug label.
5.2.3.3.
GS-2872
GS-2872 solution for infusion, 150 mg/mL, 1 mL/vial, or 2 mL/vial drug product, should be 
stored at 2 °C to 8 °C and protected from light. Storage conditions are specified on the study 
drug label.
5.3.
Dosage and Administration 
Treatment Group 1
Dose and administration of LEN, GS-5423, and GS-2872 for Treatment Group 1 are described 
below and in Table 3. 
Day 1:
Participants will receive the following study drugs. All study drugs should be administered on 
the same day (ie, no visit window is permitted for Day 1 study drug administration).
•
Oral LEN 600 mg will be administered orally with approximately 240 mL water, without 
regard to food.
•
SC LEN 927 mg will be administered within 30 minutes after oral LEN, as 2 SC injections at 
separate injection sites in the abdomen, within 15 minutes.
•
GS-5423 2550 mg IV infusion will be administered immediately following (up to 1 hour 
after) the last SC LEN injection. Infusions of GS-5423 will be administered over 
•
GS-2872 2550 mg IV infusion will be administered at least 15 minutes following (up to 
1 hour after) the completion of GS-5423 IV infusion. Infusions of GS-2872 will be 
administered over 
Participants will discontinue their baseline oral ART following administration of the complete 
study drugs on Day 1.
CCI
CCI
-
-

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Paiiicipants will self-administer oral LEN 600 mg at home with approximately 240 mL water, 
without regai·d to food, at approximately the same time as the oral LEN dose for loading on 
Day 1. 
Week 26: 
Virologic suppression (HIV-1 RNA < 50 copies/mL) from the preceding visit must be confnmed 
prior to proceeding with dosing visits. 
Infusions of GS-5423 and GS-2872 will be sequentially administered following SC LEN 
injection: 
• 
LEN 927 mg, as 2 SC injections at sepai·ate injection sites in the abdomen, within 15 minutes 
• 
GS-5423 IV infusion of2550 mg 
• 
GS-2872 IV infusion of2550 mg 
Week 52 and Every 26 Weeks During the Extension Phase: 
Virologic suppression (HIV-1 RNA < 50 copies/mL) from the preceding visit must be confnmed 
prior to proceeding with dosing visits. 
At each dosing visit, the following study diugs will be administered: 
• 
LEN 927 mg, as 2 SC injections at sepai·ate injection sites in the abdomen, within 15 minutes 
• 
Infusions of GS-5423 and GS-2872 can either be coadininistered (prefe1Ted option) or 
administered sequentially (investigator discretion) following SC LEN injection: 
-
Coadministration 
GS-5423 2550 mg and GS-2872 2550 mg IV infusion will be administered as a single 
infusion immediatel followin 
u to 1 how- after the last SC LEN 
-
Sequential administration 
GS-5423 2550 mg IV infusion will be administered immediately following (up to 
1 ho~last SC LEN injection. Infusions of GS-5423 will be adininistered 
over-
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■
GS-2872 2550 mg IV infusion will be administered at least 15 minutes following (up 
to 1 hour after) the completion of GS-5423 IV infusion. Infusions of GS-2872 will be 
administered over 
Table 3.
Treatment Group 1 Treatment Table 
Study Day
Treatment Group 1
Day 1
LEN 600 mg (two 300-mg tablets, PO)
LEN 927 mg (two 1.5-mL injections, SC)
GS-5423 2550 mg (IV infusion)
GS-2872 2550 mg (IV infusion)
Day 2
LEN 600 mg (two 300-mg tablets, PO)
Weeks 26, 52, and every 26 weeks during extension 
phasea
LEN 927 mg (two 1.5-mL injections, SC)
GS-5423 2550 mg (IV infusion)
GS-2872 2550 mg (IV infusion)
ART = antiretroviral therapy; DMC = data monitoring committee; IV = intravenous; LEN = lenacapavir; PO = orally; 
SC = subcutaneous
a
Participants in Treatment Group 1 who reach Week 52 and meet criteria to enter the extension phase will receive the study 
regimen every 26 weeks during the extension phase. 
Treatment Group 3
Day 1 Through Week 52:
Participants in Treatment Group 3 will stay on their baseline oral ART through Week 52.
Week 52:
Participants in Treatment Group 3 who are eligible and elect to participate in the extension phase 
will receive the study drugs of LEN, GS-5423, and GS-2872 as described below and in Table 4. 
Participants will receive the following study drugs. All study drugs should be administered on 
the same day (ie, no visit window is permitted for Week 52 study drug administration): 
•
Oral LEN 600 mg will be administered orally with approximately 240 mL water, without 
regard to food.
•
SC LEN 927 mg will be administered within 30 minutes after oral LEN for loading, as 
2 SC injections at separate injection sites in the abdomen, within 15 minutes. 
•
Infusions of GS-5423 and GS-2872 will either be coadministered (preferred option) or 
administered sequentially (at investigator discretion) following SC LEN injection:
Coadministration
■
GS-5423 2550 mg and GS-2872 2550 mg IV infusion will be administered as a single 
infusion immediately following (up to 1 hour after) the last SC LEN injection. 
Infusions of GS-5423 and GS-2872 will be administered over 
 minutes. 
 
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Sequential administration
■
GS-5423 2550 mg IV infusion will be administered immediately following (up to 
1 hour after) the last SC LEN injection. Infusions of GS-5423 will be administered 
over
 minutes. 
■
GS-2872 2550 mg IV infusion will be administered at least 15 minutes following (up 
to 1 hour after) the completion of GS-5423 IV infusion. Infusions of GS-2872 will be 
administered over 
 minutes. 
Participants will discontinue their baseline oral ART following administration of the complete 
study drugs on Week 52.
Week 52 + 1 Day:
Participants will self-administer oral LEN 600 mg at home with approximately 240 mL water, 
without regard to food, at approximately the same time as the oral LEN dose on Week 52.
Every 26 Weeks During the Extension Phase:
Virologic suppression (HIV-1 RNA < 50 copies/mL) from the preceding visit must be confirmed 
prior to proceeding with dosing visits. 
At each dosing visit, the following study drugs will be administered:
•
LEN 927 mg, as 2 SC injections at separate injection sites in the abdomen, within 15 minutes
•
Infusions of GS-5423 and GS-2872 will either be coadministered (preferred option) or 
sequentially administered (investigator discretion)
Table 4.
Treatment Group 3 Treatment Table
Study Day
Treatment Group 3
Day 1 through Week 52
Continue background regimen
Week 52 
LEN 600 mg (two 300-mg tablets, PO)
LEN 927 mg (two 1.5-mL injections, SC)
GS-5423 2550 mg (IV infusion)
GS-2872 2550 mg (IV infusion)
Week 52 + 1 Day (at home)
LEN 600 mg (two 300-mg tablets, PO)
Every 26 weeks during extension phase
LEN 927 mg (two 1.5-mL injections, SC)
GS-5423 2550 mg (IV infusion)
GS-2872 2550 mg (IV infusion)
ART = antiretroviral therapy; DMC = data monitoring committee; IV = intravenous; LEN = lenacapavir; PO = orally; 
SC = subcutaneous
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5.3.1.
Additional IV Infusion Instructions
GS-5423 and GS-2872, will be coadministered or administered as sequential separate 
IV infusions. If coadministered, the infusion of GS-5423 and GS-2872 will begin immediately 
following (up to 1 hour after) the last SC LEN injection. If sequentially administered, infusion of 
GS-5423 will begin immediately following (up to 1 hour after) the last SC LEN injection. 
Infusion of GS-2872 will begin at least 15 minutes following (up to 1 hour after) the completion 
of GS-5423 IV infusion. 
Initial infusions of GS-5423 and GS-2872 will be administered over 
minutes if 
coadministered as a single infusion. At subsequent coadministration dosing visits, infusions of 
GS-5423 and GS-2872 may be administered over 
 minutes and
 minutes, at investigator 
discretion. If sequentially administered, separate infusions of GS-5423 and GS-2872 will each be 
administered over 
 minutes. 
Participants will remain in a monitored clinical setting for at least 30 minutes after completion of 
the GS-5423 and GS-2872 infusion, if coadministered, or GS-2872 infusion, if sequentially 
administered. Vital signs (blood pressure, pulse, and temperature) will be recorded 30 minutes 
(± 10 minutes) after completion of the GS-5423 and GS-2872 infusion, if coadministered, or 
GS-2872 infusion, if sequentially administered. If symptoms occur, the symptoms and timing of 
occurrence will be recorded on the electronic case report form (eCRF).
Supportive medications, including but not limited to diphenhydramine, acetaminophen, and 
steroids, will be available in the clinic settings during the IV infusions.
Study drug infusion will be temporarily stopped if an infusion-related adverse reaction occurs. 
Symptom severity will be evaluated, and supportive medications provided as clinically indicated. 
For mild-moderate infusion-related reactions, after symptoms have resolved, drug infusion may 
be resumed at half the initial rate. If the symptoms, in the judgment of the investigator, 
compromise the ability to continue study-specific procedures and are considered to not be in the 
participant’s best interests, or recurrent symptoms prevent completion of infusion, the infusion 
will be permanently discontinued. 
Premedications will not be routinely administered prior to study drug administration. Participants 
who experience mild-moderate infusion-related reactions may be premedicated for subsequent 
infusions if determined necessary by the investigator. Premedication may consist of one or more 
of the following medications: diphenhydramine 25 mg (oral), ibuprofen 400 to 600 mg (oral), 
acetaminophen 500 to 650 mg (oral), prednisone 20 to 40 mg (oral) or equivalent alternative 
steroid.
The exact time of study drug administrations must be recorded in the source document. For 
additional information, refer to the study Pharmacy Manual.
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5.3.2.
Missed or Delayed Study Drug Doses
If more than 28 weeks have elapsed since the participant’s last dose, the investigator must 
contact the medical monitor, and the participant should be instructed to resume their baseline 
oral ART (or alternative ART selected by the investigator). If it is determined to be clinically 
appropriate for the participant to continue the study regimen, the participant will discontinue 
their oral ART and restart the study regimen as described in Section 5.3, which will include oral 
LEN, SC LEN, and IV infusions of GS-5423 and GS-2872 (as described on Day 1 and Day 2 for 
Treatment Group 1; and Week 52 and Week 52 + 1 day as described for Treatment Group 3). 
Subsequent doses will be administered every 26 weeks thereafter. 
5.4.
Prior and Concomitant Medications
Clinical data indicate LEN is a substrate of P-glycoprotein (P-gp) transporters, and an inhibitor 
of cytochrome P450 enzyme (CYP) 3A enzymes (moderate), breast cancer resistance protein 
(BCRP), and P-gp transporters. In vitro data suggest LEN is also a substrate of CYP3A and 
uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) enzymes. Concomitant use of LEN 
with some medications or herbal/natural supplements that are inhibitors or inducers of CYP3A, 
UGT1A1, or P-gp may result in increased or decreased LEN exposure, respectively. 
Concomitant use of LEN with some medications or herbal/natural supplements that are 
substrates of CYP3A, P-gp, or BCRP may result in increased exposure of these medications.
Representative medications listed in Table 5 and herbal/natural supplements are currently 
excluded or should be used with caution while participating in this study; this table is not 
exhaustive. Any medication that is not on the list should be reviewed by the medical monitor 
prior to screening and throughout the study. Vitamins, acetaminophen, ibuprofen, and hormonal 
medications are allowed during the study period. Participants should discontinue disallowed 
concomitant medications 30 days prior to initiation of study drug, unless otherwise specified.
Vaccinations should not be administered within 14 days prior to infusion of GS-5423 and 
GS-2872.
Table 5.
List of Representative Medications That are Prohibited or To Be Used 
With Caution Due to the Potential for Drug-Drug Interaction With 
LEN
Medication Class
Prohibited Medications
Use Discouraged and To Be Used With 
Caution
Anticoagulants
—
Dabigatran etexilate: monitoring and/or dose 
reduction may be needed for certain 
populations per prescribing information
Anticonvulsants
Carbamazepine, oxcarbazepine, 
phenobarbital, phenytoin
—
Antimycobacterials
Rifampin, rifabutin, rifapentine
—
Antiretroviral agents
Any ARV not part of the study 
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Medication Class
Prohibited Medications
Use Discouraged and To Be Used With 
Caution
Digoxin
—
Digoxin: concomitant use may result in 
increased levels of digoxin; use with caution 
and with appropriate monitoring of serum 
digoxin levels
Ergot derivatives
Ergotamine, ergonovine, 
dihydroergotamine, 
methylergonovine, ergometrine
—
Herbal/natural 
supplements
St John’s wort, echinacea, milk 
thistle (ie, silymarin), Chinese herb 
sho-saiko-to 
(or Xiao-Shai-Hu-Tang)
—
3-Hydroxy-3-
methylglutaryl-coenzyme 
A (HMG-CoA) reductase 
inhibitors
—
Concentrations of some statins may increase 
with LEN. Start with the lowest dose and 
titrate to clinical response. For each of the 
following statins, the maximum allowed 
dose is:
Simvastatin: 10 mg
Lovastatin: 20 mg
Atorvastatin: 40 mg
Careful monitoring for signs and symptoms 
of muscle weakness or myopathy, 
including rhabdomyolysis.
Phosphodiesterase-5 
inhibitors
—
Sildenafil, vardenafil, tadalafil: It is 
recommended that a single dose of sildenafil 
no more than 25 mg in 48 hours, vardenafil 
no more than 2.5 mg in 72 hours, or tadalafil 
no more than 10 mg in 72 hours be 
coadministered.
Sedatives/hypnotics
—
Midazolam, triazolam
Systemic corticosteroids
—
Concomitant use may increase corticosteroid 
exposure. Limit use to 7 days or less
ARV = antiretroviral; LEN = lenacapavir
There are no substantial safety or efficacy data regarding the concomitant administration of the 
COVID‑19 vaccines or the monkeypox vaccines (JYNNEOS and ACAM2000) and LEN, 
GS-5423, and GS-2872. Participants for whom it is clinically indicated- should receive the 
COVID‑19 and/or monkeypox vaccines, and study visits should continue as planned if 
vaccination occurs while the participant is on the study. Every attempt should be made to receive 
vaccinations > 2 weeks prior to or > 2 weeks after dosing of the study drugs. Investigators should 
follow local guidelines for concomitant administration of the COVID-19 and monkeypox 
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Tecovirimat is a drug with activity against orthopoxviruses. It is currently FDA approved for 
treatment of smallpox and available under IND for treatment of monkeypox for select patient 
groups. Clinically significant drug-drug interactions with LEN are not anticipated, contact the 
medical monitor for approval if tecovirimat is indicated for a study participant.
5.5.
Accountability for Study Drug(s) 
The investigator is responsible for ensuring adequate accountability of all used and unused study 
drug, (vials and bottles). This includes acknowledgment of receipt of each shipment of study 
drug (quantity and condition). All used and unused study drug bottles dispensed to participants 
must be returned to the site.
Each study site must keep accountability records that capture:
•
The date received and quantity of study drug (vials and bottles)
•
The date, participant number, and the study drug kit number dispensed
•
The date, quantity of used and unused study drug (bottles) returned, along with the initials of 
the person recording the information
5.5.1.
Study Drug Return or Disposal
Gilead recommends that used and unused study drug supplies be destroyed at the site. If the site 
has an appropriate standard operating procedure for drug destruction as determined by Gilead, 
the site may destroy used (empty or partially empty) and unused study drug supplies in 
accordance with that site’s approved procedural documents. A copy of the site’s approved 
procedural document will be obtained for the electronic trial master file. If the study drug is 
destroyed at the site, the investigator must maintain accurate records for all study drugs 
destroyed. Records must show the identification and quantity of each unit destroyed, the method 
of destruction, and the person who disposed of the study drugs. Upon study completion, copies 
of the study drug accountability records must be filed at the site. Another copy will be provided 
to Gilead. 
If the site does not have an appropriate standard operating procedure for study drug destruction, 
used and unused study drugs are to be sent to the designated disposal facility for destruction. 
The study monitor will provide instructions for return.
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6.
STUDY PROCEDURES
The study procedures to be conducted for each participant screened or enrolled in the study are 
presented in tabular form in Table 1 and Table 2 and described in the sections below. 
The investigator must document any deviation from the protocol procedures and notify Gilead or 
the contract research organization.
6.1.
Informed Consent
Written informed consent must be obtained from each participant before initiation of any 
study-related procedures. Refer to Section 9.1.4 for further information regarding informed 
consent.
6.2.
Screening, Participant Enrollment, and Treatment Assignment
Due to the extended laboratory processing time of the GS-5423 and GS-2872 proviral DNA 
phenotype testing (up to approximately 10 weeks), the screening visit will be performed in 
2 parts (Table 1 and Table 2). Participants meeting all of the inclusion criteria and none of the 
exclusion criteria will return to the clinic within 28 days after the Screening Visit 2 for the Day 1 
visit. 
If the screening window is exceeded in an otherwise eligible participant, the participant is 
allowed to rescreen (Screening Visit 2) 1 time after approval from the sponsor. Once a 
participant has started the rescreening process, a new screening window (28 days) will begin, 
during which time screening procedures will be repeated.
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Entry into screening does not guarantee enrollment into the study. In order to manage the total 
study enrollment, Gilead, at its sole discretion, may suspend screening and/or enrollment at any 
site or study wide at any time.
Participants must continue to take their baseline oral ART until completion of study drug 
administration at the Day 1 visit (Treatment Group 1) or Week 52 visit (Treatment Group 3). 
Once the ICF has been obtained, all screening and eligibility tests and assessments have been 
assessed, and study eligibility has been confirmed, participants will be randomized to receive 
study drug on Day 1. Participants will receive the study drugs as described in Section 5.3.
6.3.
Instructions for Study Procedures
Study procedure and assessments are outlined in Table 1 and Table 2. The extension phase will 
continue beyond Week 156 with study visits at every 12 and 24 weeks between dosing visits 
(every 26 weeks). 
6.3.1.
Adverse Events
From the time informed consent is obtained through the first administration of study drug, record 
all serious adverse events (SAEs), as well as any AEs related to protocol-required procedures, on 
the AE eCRF. All other untoward medical occurrences observed during the screening period, 
including exacerbation or changes in medical history, are to be considered medical history. 
After study drug administration, report all AEs and SAEs. See Section 7 for additional details.
6.3.2.
Concomitant Medications
Review of concomitant medications will occur at the time points shown in Table 1 and Table 2. 
See Section 5.3.1 for more information about concomitant medications.
6.3.3.
Electrocardiograms
Electrocardiograms will be assessed at the time points shown in Table 1 and Table 2.
6.3.4.
Medical History and Demography
Medical history and demographic information are to be collected for each participant at 
screening as follows:
•
Review medical history including HIV-1 disease-related events, available historical 
genotype/phenotype reports, available HIV-1 treatment history, substance (ie, illicit drug) 
use, and medications taken within 30 days of the screening visit.
•
Obtain demographic information, including sex at birth, sexual orientation, and gender 
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6.3.5.
Clinical Laboratory Assessments
Blood and urine samples will be collected throughout the study as outlined in Table 1 and 
Table 2. Laboratory assessments are listed in Table 6.
Table 6.
Laboratory Analytes
Safety Laboratory Measurements 
Chemistry
(Serum or Plasma)
Hematology
Urinalysis
Other Laboratory Measurements
ALT
AST
Alkaline phosphatase
Gamma-
glutamyltransferase
Total bilirubin
Direct bilirubin
Indirect bilirubin
Total protein
Albumin
Lactate dehydrogenase
Creatinine 
phosphokinase
Bicarbonate
Blood urea nitrogen
Calcium
Chloride
Creatinine
Glucose
Phosphorus
Magnesium
Potassium
Sodium
Uric acid
Amylase
Lipase
Thyroid-stimulating 
hormone
CBC
Color & clarity
Specific gravity
pH
Glucose
Ketones
Urobilinogen
Blood 
Nitrate
Leukocyte esterase
Protein
Uric acid
Pregnancy test
Serum pregnancy test
Serum FSH
CD4+ and CD8+ T-cell count, and 
CD4/CD8 ratio 
Proviral DNA phenotype and 
genotype
Plasma HIV-1 RNA
HIV-1 Genotype/Phenotype
HBcAb, HBsAg, HBsAb, HCVAb, 
HCV RNA
HIV reservoir assay
Immunogenicity (ADA) serum 
sample
Plasma storage samples
Pharmacokinetics
ADA = antidrug antibody; ALT = alanine aminotransferase; AST = aspartate aminotransferase; CBC = complete blood count; 
CD4 = clusters of differentiation 4; CD8 = clusters of differentiation 8; FSH = follicle-stimulating hormone; HIV = human 
immunodeficiency virus; HIV-1 = human immunodeficiency virus type 1; HBcAb = hepatitis B core antibody; 
HBsAb = hepatitis B surface antibody; HBsAg = hepatitis B surface antigen; HCV = hepatitis C virus; HCVAb = hepatitis C 
virus antibody; RNA = ribonucleic acid
Refer to Table 1 and Table 2 for collection time points.

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6.3.6.
Pharmacokinetics 
Blood sample for the determination of plasma LEN and serum GS-5423 and GS-2872 
concentrations will be collected in all participants at scheduled time points. The exact date and 
time of collection of PK samples must be carefully recorded. PK samples should be drawn from 
a separate catheter in the opposite arm from the one used for GS-5423 and GS-2872 IV infusions 
to avoid contamination. 
Concentrations of LEN in plasma samples and GS-5423 and GS-2872 in serum samples will be 
determined using validated bioanalytical methods.
6.3.6.1.
Pharmacokinetic Assessments for Treatment Group 1
The following serum PK and plasma PK samples will be collected for all participants in 
Treatment Group 1: 
Serum PK for GS-5423 and GS-2872:
•
Day 1: 0 hours (predose, ≤ 30 minutes prior to dosing of oral LEN) and within 5 minutes 
after the end of the second antibody infusion (GS-2872).
•
Week 26: 0 hours (predose, ≤ 30 minutes prior to dosing of SC LEN injection) and within 
5 minutes after the end of the second antibody infusion (GS-2872).
•
Week 52, and subsequent dosing days: 0 hours (predose, ≤ 30 minutes prior to dosing of 
SC LEN) and within 5 minutes after the end of both antibody infusions (GS-5423 and 
GS-2872), if coadministered or after the end of the second antibody infusion (GS-2872), if 
sequentially administered.
•
A single any time sample at scheduled visits as outlined in Table 1.
Plasma PK for LEN:
•
Day 1: 0 hours (predose, ≤ 30 minutes prior to dosing of oral LEN) and within 5 minutes 
after the end of the second antibody infusion (GS-2872).
•
Week 26 and subsequent dosing days: 0 hours (predose, ≤ 30 minutes prior to dosing of 
SC LEN).
•
A single any time sample at other scheduled visits as outlined in Table 1.

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6.3.6.2.
Pharmacokinetic Assessments for Treatment Group 3
The following serum PK and plasma PK samples will be collected for all participants in 
Treatment Group 3:
Serum PK for GS-5423 and GS-2872:
•
Week 52: 0 hours (predose, ≤ 30 minutes prior to dosing of oral LEN) and within 5 minutes 
after the end of both antibody infusions (GS-5423 and GS-2872), if coadministered or the 
second antibody infusion (GS-2872), if sequentially administered.
•
Week 78 and subsequent dosing visits: 0 hours (predose, ≤ 30 minutes prior to dosing of 
SC LEN).
•
A single any time sample at other scheduled visits as outlined in Table 2.
Plasma PK for LEN:
•
Week 52: 0 hours (predose, ≤ 30 minutes prior to dosing of oral LEN) and within 
5 minutes after the end of both antibody infusions (GS-5423 and GS-2872), if coadministered 
or the second antibody infusion (GS-2872), if sequentially administered.
•
Week 78 and subsequent dosing days: 0 hours (predose, ≤ 30 minutes prior to dosing of 
SC LEN).
•
A single any time sample at other scheduled visits as outlined in Table 2.
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6.3.7.
Immunogenicity Assessments
Blood samples will be collected to assess for the presence of serum ADA against GS-5423 and 
GS-2872 at scheduled time points according to Table 1 for Treatment Group 1 and Table 2 for 
Treatment Group 3.
Anti-GS-5423 and anti-GS-2872 antibodies will be determined in serum samples using validated 
bioanalytical methods.
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6.3.9.
Clinical Virology 
6.3.9.1.
Virology Testing 
6.3.9.1.1.
Virology Samples to Address the Study Objectives
Plasma samples will be collected from all participants who have provided consent for this study 
to assess HIV-1 RNA viral load at the time points specified in Table 1 and Table 2, including 
potential HIV-1 viral load retesting. Stored plasma samples may be used to assess HIV-1 
genotype and phenotype at baseline or in confirmed cases of VF, as defined in Section 6.3.9.2. 
PBMC samples will be collected at screening for proviral DNA phenotype testing. PBMC 
samples for genotyping will be collected at screening but results are not required to determine 
eligibility. PBMC samples will be collected at the additional time points specified in Table 1 and 
Table 2 and may be used to characterize the HIV-1 reservoir. 
6.3.9.2.
Virologic Failure 
Participants experiencing VR, as defined below, will be considered to be in a situation of VF and 
may be subject to resistance analysis.
6.3.9.2.1.
Management of Virologic Rebound Participants who meet the following criteria 
will be considered to have VR:
a.
At any visit after Day 1, a rebound in HIV-1 RNA ≥ 50 copies/mL, which is subsequently 
confirmed at the following scheduled or unscheduled visit, or
b.
HIV-1 RNA ≥ 50 copies/mL at study drug discontinuation
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At any visit after Day 1, if the HIV-1 RNA is ≥ 50 copies/mL and < 200 copies/mL, a reflex 
HIV-1 RNA repeat test will be conducted on stored plasma samples, if available. If the repeat 
result is < 50 copies/mL, no further action is required. If the repeat result is ≥ 50 copies/mL, 
participants will be asked to return to the clinic for a scheduled or unscheduled blood draw 
(2 to 3 weeks after the date of the original test with HIV-1 RNA ≥ 50 copies/mL) for 
confirmation of VR. If VR is confirmed and HIV-1 RNA is ≥ 50 copies/mL and 
< 200 copies/mL, the participant will be asked to return to the clinic for a scheduled or 
unscheduled blood draw (2 to 3 weeks after the date of the confirmatory draw) and the 
participant should be discussed with the medical monitor. If VR is confirmed and HIV-1 RNA is 
≥ 200 copies/mL, the plasma sample from either the first instance or the confirmation visit will 
be used for HIV-1 capsid and envelope genotypic and phenotypic testing. A plasma sample from 
the confirmation visit will be the primary sample used for HIV-1 PR, RT, and IN genotypic and 
phenotypic testing. After a participant’s first postbaseline resistance test, additional testing will 
be conducted on a case-by-case basis. Any participant may be discontinued at investigator’s 
discretion or per local treatment guidelines.
If no resistance is detected from the genotype or phenotype, the participant may remain on study 
drugs, and the HIV-1 RNA test should be repeated (2 to 3 weeks after the date of confirmed test 
with HIV-1 RNA ≥ 50 copies/mL). If HIV-1 RNA levels remain ≥ 50 copies/mL, the 
participant’s discontinuation should be discussed with the medical monitor. If resistance to study 
drug is detected, participants receiving a long-acting study drug regimen will be restarted on 
their baseline oral ART regimen (or compatible regimen selected by the investigator) and 
continue on-study follow-up but will not receive additional doses of the study drugs. 
Investigators who opt to discontinue study drugs for an individual participant must discuss with 
the medical monitor prior to study drug discontinuation.
For participants who are off study drug but remain on study, it will be the investigator’s 
discretion to manage VR.
6.3.9.2.2.
Resistance Analysis at Participant’s Last Visit
Participants with HIV-1 RNA ≥ 200 copies/mL at the last visit (ie, not confirmable) and on study 
drugs will be evaluated for resistance.
6.3.10.
Patient-Reported Outcomes
Patient-reported outcome questionnaires (if available) will be completed by participants in both 
treatment groups at the visits specified in Table 1 and Table 2, and include HIV-dependent 
quality of life (HIVDQoL), the HIV Treatment Satisfaction Questionnaire status version 
(HIVTSQs), HIV Treatment Satisfaction Questionnaire change version (HIVTSQc), and the 
HIV Treatment Preference Questionnaire (HIVTPQ).

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6.3.11.
Assessments for Early Study Drug Discontinuation
6.3.11.1.
Early Study Drug Discontinuation During the Randomized Phase
Treatment Group 1:
Participants who discontinue study drug prior to Week 52 should return to the clinic for an early 
study drug discontinuation (ESDD) visit to be performed within 72 hours of decision to 
discontinue study drug.
The participant will be asked to continue to attend scheduled study visits for at least 52 weeks 
past the last dosing visit. 
•
If the participant discontinues study drug but continues to attend the scheduled study visits 
for 52 weeks from their last dosing visit, they will complete all assessments except dosing 
and complete the study. No further follow-up visits are required. 
•
If the participant discontinues study drug and does not continue to attend study visits for 
52 weeks from their last dosing visit, the participant is required to attend follow-up visits at 
30, 90, and 180 days post-ESDD, as well as every 90 days thereafter until at least 365 days 
from the last study drug dosing visit. Refer to Table 1 for assessments. 
At the 30-, 90-, 180-, and subsequent (referred to as 270- and 365-day) follow-up visits, as 
applicable, any assessment with abnormal results that the investigator determines to have a 
possible or probable causal relationship with the study drugs will be repeated weekly (or as often 
as deemed prudent by the investigator) until the abnormality is resolved, returns to baseline, or is 
otherwise explained. Gilead may request that certain AEs be followed beyond the 
protocol-defined follow-up period.
If a participant discontinues study drug dosing (eg, as a result of an AE), every attempt should be 
made to keep the participant in the study and continue to perform the required study-related 
follow-up and procedures (see Section 3.3). If this is not possible or acceptable to the participant 
or investigator, the participant may be withdrawn from the study. 
Treatment Group 3:
Participants who discontinue from the study prior to Week 52 should return to the clinic for an 
ESDD visit to be performed within 72 hours of decision to discontinue; only a 30-day follow-up 
visit is required.
6.3.11.2.
Early Study Drug Discontinuation During the Extension Phase 
For participants who decide to discontinue study drug during the extension phase but prior to 
study completion, an ESDD visit should be performed within 72 hours of decision to discontinue 
study drug. 
The participant will be asked to continue to attend scheduled study visits for at least 
52 weeks past the last dosing visit.

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• 
If the paiiicipant discontinues study drng but continues to attend the scheduled study visits 
for 52 weeks from their last dosing visit, they will complete all assessments except dosing 
and complete the study. No fmiher follow-up visits are required. 
• 
If the paiiicipant discontinues study dmg and does not continue to attend the scheduled study 
visits for 52 weeks from their last dosing visit, the paiiicipant is required to attend follow-up 
visits at 30, 90, and 180 days post-ESDD, as well as eve1y 90 days thereafter until at least 
365 days from the last study drng dosing visit. Refer to Table 1 and Table 2 for assessments. 
At the 30-, 90-, 180-, and subsequent (refened to as 270- and 365-day) follow-up visits, as 
applicable, any assessment with abnonnal results that the investigator detennines to have a 
possible or probable causal relationship with the study diugs, will be repeated weekly ( or as 
often as deemed prndent by the investigator) until the abno1mality is resolved, retmns to 
baseline, or is othe1w ise explained. Gilead may request that ce1iain AEs be followed beyond the 
protocol-defined follow-up period. 
If a pa1iicipant discontinues study di11g dosing ( eg, as a result of an AE), eve1y attempt should be 
made to keep the paiiicipant in the study and continue to perfonn the required study-related 
follow-up and procedmes (see Section 3.3). If this is not possible or acceptable to the paiiicipant 
or investigator, the pa1iicipant may be withdi·awn from the study. 
6.4. 
Poststudy Care 
After the paiiicipant has completed/te1minated their pa1iicipation in the study, long-te1m cai·e of 
the paiiicipant will retmn to the responsibility of their primaiy treating physicians. 
6.5. 
Sample Storage 
The stored biological sainples may be used by the sponsor or its research pa1iner for additional 
testing to provide supplemental data to answer questions that relate to the main study. At the end 
of this study, these sainples ma be retained in stora e b the s onsor for a eriod u to 15 years 
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7.
ADVERSE EVENTS AND TOXICITY MANAGEMENT
7.1.
Definitions of Adverse Events and Serious Adverse Events
7.1.1.
Adverse Events
An AE is any untoward medical occurrence in a clinical study participant administered a study 
drug that does not necessarily have a causal relationship with the treatment. An AE can therefore 
be any unfavorable and/or unintended sign, symptom, or disease temporally associated with the 
use of a study drug, whether or not the AE is considered related to the study drug. Adverse 
events may also include pretreatment or posttreatment complications that occur as a result of 
protocol-specified procedures or special situations (Section 7.1.3). 
An AE does not include the following:
•
Medical or surgical procedures such as surgery, endoscopy, tooth extraction, or transfusion. 
The condition that led to the procedure may be an AE and must be reported.
•
Preexisting diseases, conditions, or laboratory abnormalities present or detected before the 
screening visit that do not worsen.
•
Situations where an untoward medical occurrence has not occurred (eg, hospitalization for 
elective surgery, social and/or convenience admissions).
•
Overdose without clinical sequelae (Section 7.1.3).
•
Any medical condition or clinically significant laboratory abnormality with an onset date 
before the ICF is signed and not related to a protocol-associated procedure is not an AE but 
rather considered to be preexisting and should be documented as medical history.
•
Preexisting events that increase in severity or change in nature after study drug initiation or 
during or as a consequence of participation in the clinical study will also be considered AEs.
7.1.2.
Serious Adverse Events
An SAE is defined as an event that, at any dose, results in the following:
•
Death
•
A life-threatening situation (Note: 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 that hypothetically might have caused death if it were more severe.)
•
In-patient hospitalization or prolongation of existing hospitalization.
•
Persistent or significant disability/incapacity.

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•
A congenital anomaly/birth defect.
•
A medically important event or reaction: such events may not be immediately 
life-threatening or result in death or hospitalization but may jeopardize the participant or may 
require intervention to prevent 1 of the other outcomes constituting SAEs. Medical and 
scientific judgment must be exercised to determine whether such an event is reportable under 
expedited reporting rules. Examples of medically important events include intensive 
treatment in an emergency room or at home for allergic bronchospasm; blood dyscrasias or 
convulsions that do not result in hospitalization; and development of drug dependency or 
drug abuse. 
7.1.3.
Study Drugs and Gilead Concomitant Medications Special Situations 
Reports
Special situations reports include all reports of medication error, abuse, misuse, overdose, 
occupational exposure, drug interactions, exposure via breastfeeding, unexpected benefit, 
transmission of infectious agents via the product, counterfeit of falsified medicine, and 
pregnancy regardless of an associated AE. 
Medication error is any unintentional error in the prescribing, dispensing, preparation for 
administration or administration of a study drug while the medication is in the control of a health 
care professional, participant, or consumer. Medication errors may be classified as a medication 
error without an AE, which includes situations of missed dose, medication error with an AE, 
intercepted medication error, or potential medication error.
Abuse is defined as persistent or sporadic intentional excessive use of a study drug by a 
participant.
Misuse is defined as any intentional and inappropriate use of a study drug that is not in 
accordance with the protocol instructions or the local prescribing information.
An overdose is defined as an accidental or intentional administration of a quantity of a study 
drug given per administration or cumulatively that is above the maximum recommended dose as 
per protocol or in the product labeling (as it applies to the daily dose of the participant in 
question). In cases of a discrepancy in drug accountability, overdose will be established only 
when it is clear that the participant has taken the excess dose(s). Overdose cannot be established 
when the participant cannot account for the discrepancy, except in cases in which the 
investigator has reason to suspect that the participant has taken the additional dose(s).
Occupational exposure is defined as exposure to a study drug as a result of one’s professional or 
nonprofessional occupation.
Drug interaction is defined as any drug/drug, drug/food, or drug/alcohol interaction.
Unexpected benefit is defined as an unintended therapeutic effect where the results are judged to 
be desirable and beneficial. 

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Transmission of infectious agents is defined as any suspected transmission of an infected agent 
through a Gilead study drug.
Counterfeit or falsified medicine is defined as any study drug with a false representation of (a) its 
identity, (b) its source, or (c) its history.
7.2.
Assessment of Adverse Events and Serious Adverse Events
The investigator or qualified subinvestigator is responsible for assessing AEs and SAEs for 
causality and severity, and for final review and confirmation of accuracy of event information 
and assessments.
7.2.1.
Assessment of Causality for Study Drugs and Procedures 
The investigator or qualified subinvestigator is responsible for assessing the relationship for each 
study drug using clinical judgment and the following considerations:
•
No: Evidence exists that the AE has an etiology other than the study drug. For SAEs, an 
alternative causality must be provided (eg, preexisting condition, underlying disease, 
intercurrent illness, concomitant medication).
•
Yes: There is reasonable possibility that the AE may have been caused by the study drug.
It should be emphasized that ineffective treatment should not be considered as causally related in 
the context of AE reporting. 
The relationship to study procedures (eg, invasive procedures such as venipuncture or biopsy) 
should be assessed using the following considerations:
•
No: Evidence exists that the AE has an etiology other than the study procedure.
•
Yes: The AE occurred as a result of protocol procedures (eg, venipuncture).
7.2.2.
Assessment of Severity
The severity of AEs will be graded using the Division of AIDS (DAIDS) Toxicity Grading 
Scale, Version 2.1 dated July 2017. For each episode, the highest grade attained should be 
reported as defined in the Toxicity Grading Scale (Appendix 11.4).
7.3.
Investigator Reporting Requirements and Instructions 
7.3.1.
Requirements for Collection Before Study Drug Initiation
After informed consent, but before initiation of study drug, the following types of events must be 
reported on the applicable eCRFs: all SAEs and any AEs that are related to protocol-required 
procedures.

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7.3.2.
Adverse Events
Following initiation of study drug, collect all AEs, regardless of cause or relationship, until the 
end of the study duration and report the AEs on the eCRFs as instructed.
All AEs and clinically significant laboratory abnormalities should be followed until resolution or 
until the AE is stable, if possible. Gilead may request that certain AEs be followed beyond the 
protocol-defined follow-up period.
7.3.3.
Serious Adverse Events
All SAEs, regardless of cause or relationship, that occur after the participant first consents to 
participate in the study (ie, signing the ICF) and throughout the duration of the study, including 
the posttreatment follow-up visit, must be reported on the applicable eCRFs and to Gilead 
Patient Safety as instructed below in this section. This also includes any SAEs resulting from 
protocol-associated procedures performed after the ICF is signed.
Any SAEs and deaths that occur throughout the duration of the study, including the 
protocol-required posttreatment follow-up period, regardless of causality, should also be 
reported.
Investigators are not obligated to actively seek SAEs after the protocol-defined follow-up period; 
however, if the investigator learns of any SAEs that occur after the protocol-defined follow-up 
period has concluded and the event is deemed relevant to the use of study drug, the investigator 
should promptly document and report the event to Gilead Patient Safety.
Instructions for reporting SAEs are described in Section 7.4.1.
7.3.4.
Study Drug Special Situations Reports
All study drug special situation reports (SSRs) that occur from study drug initiation and 
throughout the duration of the study, including the posttreatment follow-up visit, must be 
reported to Gilead Patient Safety (Section 7.4.2). Adverse events and SAEs resulting from SSRs 
must be reported in accordance with the AE and SAE reporting guidance (Section 7.3).
7.3.5.
Concomitant Medications Reports
7.3.5.1.
Gilead Concomitant Medications Special Situations Report
Special situations reports involving a Gilead concomitant medication (not considered study 
drug), that occur after the participant first consents to participate in the study (ie, signing of the 
ICF) and throughout the duration of the study, including the posttreatment follow-up visit, must 
be reported to Gilead Patient Safety utilizing the paper SSR (Section 7.4.2.2).

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7.3.5.2.
Non-Gilead Concomitant Medications Report
Special situations involving non-Gilead concomitant medications do not need to be reported on 
the SSR form; however, for special situations that result in AEs because of a non-Gilead 
concomitant medication, the AE should be reported on the AE eCRF. 
Any inappropriate use of concomitant medications prohibited by this protocol should not be 
reported as “misuse,” but may be more appropriately documented as a protocol deviation.
All clinical sequelae in relation to these SSRs will be reported as AEs or SAEs at the same time 
using the AE eCRF and/or the SAE eCRF. Details of the symptoms and signs, clinical 
management, and outcome will be reported, when available.
7.4.
Reporting Process for Serious Adverse Events and Special Situations Reports
7.4.1.
Serious Adverse Event Reporting Process
For fatal or life-threatening events, copies of hospital case reports, autopsy reports, and other 
documents are also to be transmitted by email or fax when requested and applicable. 
Transmission of such documents should occur without personal participant identification, 
maintaining the traceability of a document to the participant identifiers.
Additional information may be requested to ensure the timely completion of accurate safety 
reports.
Any medications necessary for treatment of the SAE must be recorded onto the concomitant 
medication section of the participant’s eCRF and the SAE narrative section of the Safety Report 
Form eCRF.
7.4.1.1.
Electronic Serious Adverse Event Reporting Process
Site personnel will record all SAE data on the applicable eCRFs and from there transmit the SAE 
information to Gilead Patient Safety within 24 hours of the investigator’s knowledge of the 
initial event and of any updates from the time of the ICF signature throughout the duration of the 
study, including the protocol-required posttreatment follow-up period. 
If for any reason it is not possible to record and transmit the SAE information electronically, 
record the SAE on the paper SAE reporting form and transmit within 24 hours to:
Gilead Patient Safety 
Email: Safety_FC@gilead.com
or
Fax: 1-650-522-5477

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If an SAE has been reported via a paper form because the eCRF database has been locked, no 
further action is necessary. If the database is not locked, any SAE reported via paper must be 
transcribed as soon as possible on the applicable eCRFs and transmitted to Gilead Patient Safety.
7.4.2.
Special Situations Reporting Process 
7.4.2.1.
Electronic Special Situations Reporting Process for Study Drug
Site personnel will record all SSR data on the applicable eCRFs and from there transmit the SSR 
information within 24 hours of the investigator’s knowledge to Gilead Patient Safety from study 
drug initiation throughout the duration of the study, including the protocol-required 
posttreatment follow-up period. 
If for any reason it is not possible to record and transmit the SSR information electronically, 
record the SSR on the paper special situations reporting form and transmit within 24 hours to:
Gilead Patient Safety 
Email: Safety_FC@gilead.com 
or
Fax: 1-650-522-5477
If an SSR has been reported via a paper form because the eCRF database has been locked, no 
further action is necessary. If the database is not locked, any SSR reported via paper must be 
transcribed as soon as possible on the applicable eCRFs and transmitted to Gilead Patient Safety.
See Section 7.4.2.2 for instructions on reporting special situations with Gilead concomitant 
medications. 
7.4.2.2.
Reporting Process for Gilead Concomitant Medications
Special situations that involve Gilead concomitant medications that are not considered study 
drug must be reported within 24 hours of the investigator’s knowledge of the event to Gilead 
Patient Safety utilizing the paper SSR form and transmitted to:
Gilead Patient Safety 
Email: Safety_FC@gilead.com
or
Fax: 1-650-522-5477 
Any inappropriate use of concomitant medications prohibited by this protocol should not be 
reported as “misuse,” but may be more appropriately documented as a protocol deviation.
Special situations involving non-Gilead concomitant medications do not need to be reported on 
the SSR form; however, special situations that result in AEs because of a non-Gilead 
concomitant medication, must be reported on the AE eCRF.

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7.4.2.3.
Pregnancy Reporting Process
The investigator should report pregnancies identified after initiation of study drug and 
throughout the study, including the protocol-required posttreatment follow-up period per 
Appendix 11.3. Pregnancies should be reported to Gilead Patient Safety within 24 hours of 
becoming aware of the pregnancy using the pregnancy report form. Contact details for 
transmitting the pregnancy report form are as follows:
Gilead Patient Safety 
Email: Safety_FC@gilead.com
or
Fax: 1-650-522-5477
The pregnancy itself is not considered an AE, nor is an induced elective abortion to terminate a 
pregnancy without medical reasons.
All other premature terminations of pregnancy (eg, a spontaneous abortion, an induced 
therapeutic abortion because of complications or other medical reasons) must be reported within 
24 hours as an SAE, as described in Section 7.4.1. The underlying medical reason for this 
procedure should be recorded as the AE term.
A spontaneous abortion is always considered to be an SAE and will be reported as described in 
Section 7.4.1. Furthermore, any SAE occurring as an adverse pregnancy outcome after the study 
must be reported to the Gilead Patient Safety.
The participant should receive appropriate monitoring and care until the conclusion of the 
pregnancy. The outcome of the pregnancy should be reported to Gilead Patient Safety using the 
pregnancy outcome report form. If the end of the pregnancy occurs after the study has been 
completed, the outcome should be reported directly to Gilead Patient Safety.
Gilead Patient Safety contact information is as follows: email: Safety_FC@gilead.com and
fax: +1 (650) 522-5477. 
Refer to Appendix 11.3 for Pregnancy Precautions, Definition for Childbearing Potential, and 
Contraceptive Requirements.
7.5.
Gilead Reporting Requirements
Depending on relevant local legislation or regulations, including the applicable US FDA Code of 
Federal Regulations, the European Union (EU) Clinical Trials Directive (2001/20/EC) and 
relevant updates, and other country-specific legislation or regulations, Gilead may be required to 
expedite to worldwide regulatory agencies reports of SAEs, which may be in the form of line 
listings, serious adverse drug reactions, or suspected unexpected serious adverse reactions. 
In accordance with the EU Clinical Trials Directive (2001/20/EC), Gilead or a specified designee 
will notify worldwide regulatory agencies and the relevant independent ethics committee in 
concerned Member States of applicable suspected unexpected serious adverse reactions as 
outlined in current regulations.

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Assessment of expectedness for SAEs will be determined by Gilead using reference safety 
information specified in the IB as applicable. 
All investigators will receive a safety letter notifying them of relevant suspected unexpected 
serious adverse reaction reports associated with any study drug. The investigator should notify 
the IRB or independent ethics committee of suspected unexpected serious adverse reaction 
reports as soon as is practical, where this is required by local regulatory agencies, and in 
accordance with the local institutional policy. 
To minimize the possibility of exposing participants to unusual risk, the safety information from 
this study will also be reviewed by an independent DMC. The DMC will make recommendations 
regarding the study according to the DMC charter. 
7.6.
Clinical Laboratory Abnormalities and Other Abnormal Assessments as 
Adverse Events or Serious Adverse Events
Laboratory abnormalities without clinical significance are not to be recorded as AEs or SAEs. 
However, laboratory abnormalities (eg, clinical chemistry, hematology, urinalysis) that require 
medical or surgical intervention or lead to study drug interruption, modification, or 
discontinuation must be recorded as an AE, as well as an SAE, if applicable. In addition, 
laboratory or other abnormal assessments (eg, ECG, x-rays, vital signs) that are associated with 
signs and/or symptoms must be recorded as an AE or SAE if they meet the definition of an AE 
or SAE as described in Sections 7.1.1 and 7.1.2. If the laboratory abnormality is part of a 
syndrome, record the syndrome or diagnosis (eg, anemia), not the laboratory result (ie, decreased 
hemoglobin).
Severity should be recorded and graded according to the DAIDS Toxicity Grading Scale, 
Version 2.1 dated July 2017 (Appendix 11.4). For AEs associated with laboratory abnormalities, 
the event should be graded on the basis of the clinical severity in the context of the underlying 
conditions; this may or may not be in agreement with the grading of the laboratory abnormality.
The CTCAE Version 5 grading scale will be used to grade AEs determined to be infusion-related 
reactions (see Table 7).

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Table 7.
The Common Terminology Criteria for Adverse Events Version 5 
Grading Scale
CTCAE Term
Grade 
1
Grade 
2
Grade 
3
Grade 
4
Grade 
5
Infusion-related 
reaction
Mild transient 
reaction; infusion 
interruption not 
indicated; 
intervention not 
indicated
Therapy or 
infusion 
interruption 
indicated but 
responds promptly 
to symptomatic 
treatment 
(eg, antihistamines, 
NSAIDS, 
narcotics, 
IV fluids); 
prophylactic 
medications 
indicated for 
≤ 24 hours
Prolonged 
(eg, not rapidly 
responsive to 
symptomatic 
medication and/or 
brief interruption 
of infusion); 
recurrence of 
symptoms 
following initial 
improvement; 
hospitalization 
indicated for 
clinical sequelae
Life-threatening 
consequences; 
urgent 
intervention 
indicated
Death
CTCAE = Common Terminology Criteria for Adverse Events; IV = intravenous; NSAIDs = nonsteroidal anti-inflammatory 
drugs
7.7.
Toxicity Management 
All clinical and clinically significant laboratory toxicities will be managed according to uniform 
guidelines detailed in Appendix 11.5, and as outlined below:
Grade 3 or 4 clinically significant laboratory abnormalities should be confirmed by repeat testing 
as soon as possible, and preferably within 3 calendar days after receipt of the original test results.
Treatment-emergent toxicities will be noted by the investigator and brought to the attention of 
the medical monitor, and the appropriate course of action will be discussed and decided. Whether 
or not considered treatment-related, all participants experiencing AEs must be monitored 
periodically until symptoms subside, any abnormal laboratory values have resolved or returned 
to baseline levels or they are considered irreversible, or until there is a satisfactory explanation 
for the changes observed.
Any questions regarding toxicity management should be directed to the medical monitor.
All clinical sequelae in relation to SSRs will be reported as AEs or SAEs at the same time using 
the AE eCRF and/or the SAE report form. Details of the symptoms and signs, clinical 
management, and outcome will be reported, when available.
For management of infusion-related reactions, please see Section 5.3.1. 

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7.7.1.
Management of ISRs of Grade 3 or Higher or Persisting for More Than 
26 Weeks
In clinical studies of SC LEN, Grade 3 or higher AEs of ISRs were uncommon. Some 
participants experienced AEs of injection site nodule and induration, which decreased in size 
over 6 months or longer. For AEs of ISRs related to SC LEN injection that are Grade 3 or higher 
or persisting for more than 26 weeks, particularly nodule and/or induration, the investigator must 
contact the medical monitor and discuss the appropriate next steps for further assessment and 
management of ISR. ISRs that last longer than 26 weeks will be followed clinically until 
resolution or study completion, and the time of resolution will be documented. Photographic 
documentation of ISRs that meet above criteria is recommended but not mandatory. If obtained, 
documentation may be shared with the sponsor and study team.
7.7.2.
Management of Ophthalmologic Toxicities/Symptoms of Ocular Disease
As described in the GS-5423 IB, in normal human tissue and rat tissue cross-reactivity studies, 
plasma membrane staining with a related fluoresceinated antibody, 3BNC117-FITC, was 
observed in conjunctival recesses in the human eye (1/3 donors) and the rat eye (1/2 donors). 
These findings were not observed in a normal human tissue cross-reactivity study of 3BNC117 
and GS-5423. Additionally, in more than 150 participants in 5 clinical studies of 3BNC117, 
eye-related symptoms were carefully monitored, and ophthalmology exams, including slit-lamp 
examinations, were performed. These ophthalmology exams did not reveal any changes from 
baseline or pathology consistent with an effect related to a therapeutic antibody. However, if 
symptoms of ocular disease (eg, pruritus, conjunctival erythema, dryness, increased lacrimation, 
diplopia) develop after study infusions and persist for > 48 hours, or more urgent management is 
clinically indicated, participants should be promptly referred to an ophthalmologist for diagnosis 
and management.
7.7.3.
Management of Other Toxicities
Unless otherwise specified in Section 7.7, toxicities will be managed according to the guidelines 
below and as described in Appendix 11.5.
•
All clinically significant Grade 3 and 4 laboratory abnormalities should be repeated within 
3 calendar days to confirm toxicity grade. Confirmation of toxicity grade is required prior to 
the next dose of study drug for any Grade 3 and 4 laboratory abnormality that in the opinion 
of the investigator is clinically significant and may pose a risk to the participant’s safety.
•
Clinical events and clinically significant laboratory abnormalities will be graded according to 
the DAIDS Toxicity Grading Scale, Version 2.1 dated July 2017 (refer to Appendix 11.4).
Any questions regarding toxicity management should be directed to the medical monitor.

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7.7.3.1.
Grades 1 and 2 Laboratory Abnormality or Clinical Event Management of 
Clinical and Laboratory Adverse Events
Continue investigational medicinal product at the discretion of the investigator.
7.7.3.2.
Grade 3 Laboratory Abnormality or Clinical Event
•
For Grade 3 clinically significant laboratory abnormality or clinical event, investigational 
medicinal product may be continued if the event is considered to be unrelated to 
investigational medicinal product.
•
For a Grade 3 clinical event, or clinically significant laboratory abnormality confirmed by 
repeat testing, that is considered to be related to investigational medicinal product, 
investigational medicinal product should be withheld until the toxicity returns to Grade 2 or 
lower.
•
If a laboratory abnormality recurs to Grade 3 or 4 following rechallenge with investigational 
medicinal product and is considered related to investigational medicinal product, then 
investigational medicinal product should be permanently discontinued, and the participant 
managed according to local practice including switching to an effective alternative 
ARV regimen with consideration of the long duration of exposure of investigational 
medicinal products and the risk of resistance if viremic. Recurrence of laboratory 
abnormalities considered unrelated to investigational medicinal product may not require 
permanent discontinuation.
7.7.3.3.
Grade 4 Laboratory Abnormality or Clinical Event
For a Grade 4 clinical event or clinically significant Grade 4 laboratory abnormality confirmed 
by repeat testing that is considered related to investigational medicinal product, investigational 
medicinal product should be permanently discontinued, and the participant managed according to 
local practice including switching to an effective alternative ARV regimen with consideration of 
the long duration of exposure of investigational medicinal products and the risk of resistance if 
viremic. The participant should be followed as clinically indicated until the laboratory 
abnormality returns to baseline or is otherwise explained, whichever occurs first. A clinically 
significant Grade 4 laboratory abnormality that is not confirmed by repeat testing should be 
managed according to the algorithm for the new toxicity grade.
Investigational medicinal product may be continued without dose interruption for a clinically 
nonsignificant Grade 3-4 laboratory abnormality (eg, creatine kinase elevation after strenuous 
exercise, or triglyceride elevation that is nonfasting or that can be medically managed) or a 
Grade 3-4 clinical event considered unrelated to investigational medicinal product.

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7.8.
Internal Safety Team 
Per Gilead’s signal management process, an internal safety team consisting of members not 
directly involved in conduct of the study may review clinical study data for safety reasons. 
The internal safety team provides recommendations to relevant safety committees within 
Gilead’s signal management process on further actions to protect participants involved in the 
LEN, GS-5423, and GS-2872 development program.

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8.
STATISTICAL CONSIDERATIONS
Details of the statistical methods will be provided in the statistical analysis plan, including any 
deviations from the original statistical analyses planned.
8.1.
Analysis Objectives and Endpoints
Objectives and endpoints are listed in Section 2.
8.2.
Planned Analyses
8.2.1.
Interim Analysis 
Before the final analysis, interim analyses may be conducted and the analyses may be submitted 
to regulatory agencies to seek guidance for the overall clinical development program and to 
support regulatory filings. Also, interim analyses may be used for publication and presentation at 
scientific meetings.
8.2.1.1.
Planned Interim Analyses 
In addition to the primary analysis, there will be 1 planned interim analysis:
•
Week 52 analysis after all participants have completed their Week 52 visit or prematurely 
discontinued study drug
8.2.1.2.
Data Monitoring Committee Analysis
There will be 1 planned DMC analysis after approximately the first 50% of participants enrolled 
have completed their Week 12 visit or prematurely discontinued from the study drug. Safety data 
will be reviewed by the DMC without formal stopping rules. A futility assessment will be 
conducted based on the proportion of participants with HIV-1 RNA ≥ 50 copies/mL at Week 12 
as defined by the FDA-defined snapshot algorithm. If the lower bound of 95% CI of treatment 
difference (Treatment Group 1–Treatment Group 3) is > 0, the DMC may recommend 
discontinuation of Treatment Group 1 for futility. The final decision to discontinue a treatment 
group will be made by the sponsor based on the totality of efficacy, safety, PK, and other data.
In addition, if 4 or more participants in Treatment Group 1 experience confirmed VR (as defined 
in Section 6.3.9.2.2) before all participants reach Week 26, an ad hoc DMC meeting may be 
convened to assess the data.
A DMC meeting may be convened, and the supporting analyses conducted at other times during 
the study as deemed necessary. Further details will be provided in the DMC charter.
Lastly, no alpha penalty due to the DMC analyses will be applied for the primary analysis of the 
primary efficacy endpoint given that the study is not adequately powered for a formal efficacy 
evaluation. 

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8.2.2.
Primary Analysis 
The primary analysis of the primary endpoint will be conducted after all participants enrolled 
have completed the Week 26 visit or have prematurely discontinued study drug, outstanding data 
queries have been resolved or adjudicated as unresolvable, and the data have been cleaned and 
finalized for the analysis. This analysis of the primary endpoint will serve as the final analysis 
for this endpoint and will be used to evaluate the efficacy of the long-acting regimen consisting 
of LEN, GS-5423, and GS-2872.
8.2.3.
Final Analysis
The final analysis will be performed after all participants have completed or prematurely 
discontinued from the study, outstanding data queries have been resolved or adjudicated as 
unresolvable, and the data have been cleaned and finalized.
8.3.
Analysis Conventions
8.3.1.
Analysis Sets
8.3.1.1.
Efficacy
The primary analysis set for efficacy analysis is defined as the Full Analysis Set, which will 
include all randomized participants who have received at least 1 dose of either the complete 
long-acting study drug regimen (ie, SC LEN + GS-5423 + GS-2872) or baseline oral ART 
regimen on or after Day 1. Participants will be grouped according to the treatment to which they 
were randomized.
8.3.1.2.
Safety
The primary analysis set for safety analyses is defined as the Safety Analysis Set, which will 
include all participants who (1) are randomized into the study and (2) have received at least 
1 dose of study drug. Participants will be grouped according to the treatment which they actually 
received.
8.3.1.3.
Pharmacokinetics
8.3.1.3.1.
Pharmacokinetic Analysis Set
The primary analysis set for general PK analyses is defined as the PK Analysis Set, which will 
include all randomized participants who have received at least 1 dose of GS-5423, GS-2872, or 
LEN, and have at least 1 nonmissing PK concentration value reported by the PK laboratory for 
the corresponding analytes (eg, GS-5423, GS-2872, LEN, and metabolites, if applicable).

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8.3.1.4.
Immunogenicity
The Immunogenicity Analysis Set will include all randomized participants who received at least 
1 dose of GS-5423 or GS-2872 and had at least 1 nonmissing value for each immunogenicity 
evaluation (ie, anti–GS-5423 antibody or anti–GS-2872 antibody).
8.3.2.
Data Handling Conventions
HIV-1 RNA reported results of “No HIV-1 RNA detected” and “< 20 copies/mL HIV-1 RNA 
Detected” will be imputed as 19 copies/mL for analysis purposes. The HIV-1 RNA reported 
results will be used for listing purposes.
Laboratory data (other than HIV-1 RNA) that are continuous in nature but are above the upper 
limit of quantitation or less than the lower limit of quantitation (LLOQ) will be imputed to the 
value of the upper or lower limit plus or minus 1 significant digit, respectively (eg, if the result of 
a continuous laboratory test is < 5.4, a value of 5.3 will be assigned).
Missing data can have an impact upon the interpretation of the study data. In general, values for 
missing data will not be imputed. However, a missing pretreatment laboratory result would be 
treated as normal (ie, no toxicity grade) for the laboratory abnormality summary.
8.4.
Demographic and Baseline Characteristics Analysis
Demographic and baseline measurements will be summarized using standard descriptive 
methods including sample size, mean, SD, median, first quartile, third quartile, minimum, and 
maximum for continuous variables and frequency and percentages for categorical variables.
Demographic summaries will include sex at birth, sexual orientation, gender identity, race, 
ethnicity, and age.
Baseline data will include a summary of body weight, height, body mass index, and HIV-1 
infection (eg, CD4+ T-cell count).
CCI

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8.5.
Efficacy Analysis
8.5.1.
Primary Analysis
The primary efficacy endpoint is the proportion of participants with HIV-1 RNA ≥ 50 copies/mL 
at Week 26 as determined by the US FDA–defined snapshot algorithm {U. S. Department of 
Health and Human Services 2015}. The primary analysis of the efficacy will be based on the Full 
Analysis Set (FAS).
The 2-sided 95% CI of the difference in the proportion of participants with HIV-1 RNA 
≥ 50 copies/mL at Week 26 between Treatment Group 1 and Treatment Group 3 will be 
constructed based on an unconditional exact method using 2 inverted 1-sided tests {Chan 1999}. 
8.5.2.
Secondary Analyses
The proportion of participants with HIV-1 RNA ≥ 50 copies/mL at Week 52 and the proportion 
of participants with HIV-1 RNA < 50 copies/mL at Weeks 26 and 52 as determined by the 
US FDA-defined snapshot algorithm will be analyzed using the same methods as for the primary 
efficacy endpoint based on the FAS. 
The changes from baseline in CD4+ T-cell count at Week 26 and Week 52 will be summarized 
by treatment group using descriptive statistics. The differences in changes from baseline in 
CD4+ T-cell count between the treatment groups (Treatment Group 1 versus Treatment Group 3) 
and the associated 95% confidence intervals will be constructed using analysis of covariance 
models, including baseline CD4+ T-cell count as a covariate and treatment (Treatment Group 1 
versus Treatment Group 3) as a fixed effect in the models.
8.6.
Safety Analysis
Safety data will be summarized by treatment group using the Safety Analysis Set. For Treatment 
Group 1, all safety data collected on or after the first dose date of study drug will be included. 
For Treatment Group 3, all safety data collected on or after the first dose date of study drug and 
up to 30 days after the last dose date will be included. All data will be summarized by treatment 
according to the study drug received. All collected data will be included in data listings for all 
enrolled participants.
8.6.1.
Extent of Exposure
A participant’s extent of exposure to study drug will be generated from the study drug 
administration data in the case report form (CRF). Exposure data will be summarized by 
treatment group.
Dosing information for individual participants will be listed.

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8.6.2.
Adverse Events
Clinical and laboratory AEs will be coded using the current version of the Medical Dictionary 
for Regulatory Activities (MedDRA). System organ class (SOC), high-level group term, 
high-level term (HLT), preferred term (PT), and lower-level term will be attached to the clinical 
database.
Events will be summarized on the basis of the date of onset for the event. For Treatment 
Group 1, a TEAE will be defined as any AE that begins on or after the date of first dose of study 
drug. For Treatment Group 3, a TEAE will be defined as any AE that begins on or after the date 
of first dose of study drug and up to 30 days after the last dose date; or any AE leading to study 
drug discontinuation.
Summaries (number and proportion of participants) of treatment-emergent AEs and SAEs (by 
SOC, HLT [if applicable], and PT) by treatment group will be provided. Additional summaries 
will include summaries for AEs by grade, investigator’s assessment of relationship to study drug, 
and effect on study drug dosing.
8.6.3.
Laboratory Evaluations
Selected laboratory data (using conventional units) will be summarized using only observed data. 
Absolute values and change from baseline at all scheduled visits will be summarized by 
treatment group.
Graded laboratory abnormalities will be defined using the grading scheme in The DAIDS 
Toxicity Grading Scale, Version 2.1, dated July 2017 (Appendix 11.4).
The number and proportion of participants experiencing treatment-emergent laboratory 
abnormalities will be summarized by treatment group. For Treatment Group 1, 
treatment-emergent laboratory abnormalities are defined as values that increase at least 1 toxicity 
grade from baseline at any time postbaseline. For Treatment Group 3, treatment-emergent 
laboratory abnormalities are defined as values that increase at least 1 toxicity grade from baseline 
at any time postbaseline up to and including the date of last dose of study drug plus 30 days. If 
baseline data are missing, then any graded abnormality (ie, at least a Grade 1) will be considered 
treatment emergent. 
All laboratory abnormalities will be included in a data listing.
8.6.4.
Other Safety Evaluations
Vital signs and safety ECG data will be summarized by treatment group.
8.7.
Adjustments for Multiplicity
No adjustments will be made for multiplicity. Nominal 95% CIs and tests performed at the 
nominal 0.05 alpha level will be provided.

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8.8.
Pharmacokinetic Analysis 
The serum or plasma concentrations of each analyte (GS-5423, GS-2872, and LEN [and 
metabolites, if applicable]) over time, including trough concentrations at Weeks 26 and 52, will 
be listed and summarized by nominal time and treatment group using descriptive statistics. 
PK parameters (AUC0-t, AUClast, t1/2, Cmax, Tmax, as appropriate) will be listed and summarized 
by treatment group using descriptive statistics. 
Additional population PK analysis and analysis of the relationship between PK and efficacy or 
safety endpoints may be performed, as appropriate. 
8.9.
Immunogenicity Analysis
Immunogenicity to GS-5423 and GS-2872 will be assessed using a 3-tier (screen, confirmatory, 
and titer) approach on study samples using a validated immunoassay. The incidence of 
anti-GS-5423 and anti-GS-2872 antibodies will be summarized by treatment group for the 
Immunogenicity Analysis Set. Titer summaries may also be generated, if relevant. 
8.10.
Patient-reported Outcomes Analysis
The patient-reported outcomes pertaining to quality of life (HIVDQoL), treatment satisfaction 
(HIVTSQs/HIVTSQc), and treatment preference (HIVTPQ) may be summarized by treatment 
group and visit using descriptive statistics.
8.11.
Sample Size
A sample size of 50 participants in Treatment Group 1 and 25 participants in Treatment Group 3 
was chosen to estimate the proportion of participants with HIV-1 RNA ≥ 50 copies/mL at 
Week 26 as determined by the US FDA-defined snapshot algorithm to allow for the planning of 
Phase 3 studies. This study is not formally powered for treatment comparison.
Assuming no failure (0%) in Treatment Group 3 at Week 26, the number of failures in Treatment 
Group 1 at Week 26 would need to be ≥ 8 (16%) for the 95% CI for the difference between 
treatment (Treatment Group 1 versus Treatment Group 3) in the proportion of participants with 
HIV-1 RNA ≥ 50 copies/mL at Week 26 to exclude 0. Similarly, assuming 1 failure (4%) in 
Treatment Group 3 at Week 26, the number of failures in Treatment Group 1 would need to be 
≥ 12 (24%) for the 95% CI for the difference between treatment (Treatment Group 1 versus 
Treatment Group 3) in the proportion of participants with HIV-1 RNA ≥ 50 copies/mL at 
Week 26 to exclude 0. The 95% CI is estimated based on an exact unconditional method {Chan 
1999}.
If the underlying incidence of a specific AE is 5%, there is a 92.3% chance of observing at least 
1 AE among 50 participants in Treatment Group 1 and a 72.3% chance of observing at least 
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8.12.
Data Monitoring Committee 
A multidisciplinary DMC consisting of non-Gilead personnel will review the progress of the 
study, perform interim reviews of safety and efficacy data, and provide recommendation to 
Gilead whether the nature, frequency, and severity of AEs associated with study drug warrant the 
early termination of the study in the best interests of the participants, whether the study should 
continue as planned, or whether the study should continue with modifications. The DMC may 
also provide recommendations as needed regarding study design.
The DMC’s specific activities will be defined by a mutually agreed charter, which will define the 
DMC’s membership, conduct, and meeting schedule.
While the DMC will be asked to advise Gilead regarding future conduct of the study, including 
possible early study or treatment group termination, Gilead retains final decision-making 
authority on all aspects of the study.

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9.
RESPONSIBILITIES
9.1.
Investigator Responsibilities
9.1.1.
Good Clinical Practice
The investigator will ensure that this study is conducted in accordance with ICH E6(R2) 
addendum to its guideline for GCP and applicable laws and regulations.
9.1.2.
Financial Disclosure
The investigator and subinvestigators will provide prompt and accurate documentation of their 
financial interest or arrangements with the sponsor or proprietary interests in the study drug. This 
documentation must be provided before the investigator’s (and any subinvestigator’s) 
participation in the study. The investigator and subinvestigator agree to notify Gilead of any 
change in reportable interests during the study and for 1 year following completion of the study. 
Study completion is defined as the date when the last participant completes the protocol-defined 
activities.
9.1.3.
Institutional Review Board/Independent Ethics Committee Review and 
Approval
The investigator (or Gilead as appropriate according to local regulations) will submit this 
protocol, ICF, and any accompanying material to be provided to the participant (such as 
advertisements, participant information sheets, or descriptions of the study used to obtain 
informed consent) to an IRB. The investigator will not begin any study participant activities until 
approval from the IRB has been documented and provided as a letter to the investigator.
Before implementation, the investigator will submit to and receive documented approval from 
the IRB for any modifications made to the protocol or any accompanying material to be provided 
to the participant after initial IRB approval, with the exception of those necessary to reduce 
immediate risk to study participants.
9.1.4.
Informed Consent
The investigator is responsible for obtaining written informed consent from each individual 
participating in this study after adequate explanation of the aims, methods, objectives, and 
potential hazards of the study before undertaking any study-related procedures. The investigator 
must use the most current IRB-approved ICF for documenting written informed consent. Each 
ICF (or assent as applicable) will be appropriately signed and dated by the participant or the 
participant’s legally authorized representative, the person conducting the consent discussion, and 
an impartial witness (if required by IRB or local requirements). 

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The investigator must ensure that paiiicipants anonymity will be strictly maintained and that 
their identities are protected from unauthorized paiiies. Only an identification code and any other 
unique identifier(s) as allowed by local law (such as year of bi1ih) will be recorded on any fo1m 
or biological sample submitted to Gilead, IRB, or the laborato1y. Laborato1y specimens must be 
labeled in such a way as to protect paii icipant identity while allowing the results to be recorded 
to the proper pa1iicipant. Note: The investigator must keep a screening log with details for all 
paii icipants screened and enrolled in the study, in accordance with the site procedures and 
regulations. paiticipant data will be processed in accordance with all applicable regulations. 
The investigator agrees that all info1mation received from Gilead, including but not limited to the 
IB, this protocol, eCRFs, study drng info1mation, and any other study info1mation, remains the 
sole and exclusive prope1iy of Gilead during the conduct of the study and thereafter. This 
info1mation is not to be disclosed to any third paiiy ( except employees or agents directly 
involved in the conduct of the study or as required by law) without prior written consent from 
Gilead. The investigator fmi her agrees to take all reasonable precautions to prevent the 
disclosure by any employee or agent of the investigational site to any third party or othe1wise 
into the public domain. 
9.1.6. 
Study Files and Retention of Records 
The investigator must maintain adequate and accurate records to enable the conduct of the study 
to be fully documented and the study data to be subsequently verified. These documents should 
be classified into at least the following 2 categories: (1) investigator's study file and 
(2) paii icipant clinical source documents. 
The investigator's study file will contain the protocoVamendments, eCRFs, IRB, and 
governmental approval with conespondence, the ICF(s), diug records, staff cmTiculum vitae and 
authorization fo1ms, and other appropriate documents and conespondence. 
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The required source data should include sequential notes containing at least the following 
information for each participant:
•
Participant identification
•
Documentation that participant meets eligibility criteria (ie, medical history, physical 
examination, and confirmation of diagnosis [to support inclusion and exclusion criteria])
•
Documentation of the reason(s) a consented participant is not enrolled
•
Participation in study (including study number)
•
Study discussed and date of informed consent
•
Dates of all visits
•
Documentation that protocol-specific procedures were performed
•
Results of efficacy parameters, as required by the protocol
•
Start and end date (including dose regimen) of study drug, including dates of dispensing and 
return
•
Record of all AEs and other safety parameters (start and end date; causality and severity) and 
documentation that adequate medical care has been provided for any AE
•
Concomitant medication (start and end date; dose if relevant; dose changes)
•
Date of study completion and reason for early discontinuation, if it occurs
All clinical study documents must be retained by the investigator for at least 2 years or according 
to local laws, whichever is longer, after the last approval of a marketing application in an 
ICH region (ie, the US, Europe, or Japan) and until there are no pending or planned marketing 
applications in an ICH region; or, if no application is filed or if the application is not approved 
for such indication, for 2 years after the investigation is discontinued and regulatory authorities 
have been notified. Investigators may be required to retain documents longer if specified by 
regulatory requirements, by local regulations, or by an agreement with Gilead. The investigator 
must notify Gilead before destroying any clinical study records.
Should the investigator wish to assign the study records to another party or move them to another 
location, Gilead must be notified in advance.

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If the investigator cannot provide for this archiving requirement at the investigational site for any 
or all of the documents, special arrangements must be made between the investigator and Gilead 
to store these records securely away from the site so that they can be returned sealed to the 
investigator in case of an inspection. When source documents are required for the continued care 
of the participant, appropriate copies should be made for storage away from the site.
9.1.7.
Case Report Forms
An eCRF casebook will be completed by an authorized study personnel member whose training 
for this function is completed in the electronic data capture (EDC) system unless otherwise 
directed. The eCRF casebook will only capture the data required per the protocol schedule of 
events and procedures, unless collected by a nonelectronic data capture vendor system (eg, 
central laboratory). The Inclusion/Exclusion Criteria and Enrollment eCRFs should be completed 
only after all data related to eligibility are available. Data entry should be performed in 
accordance with the CRF Completion Guidelines provided by the sponsor. Subsequent to data 
entry, a study monitor may perform source data verification. System-generated or manual queries 
will be issued in the EDC system as data discrepancies are identified by the study monitor or 
Gilead personnel who routinely review the data for completeness, correctness, and consistency. 
The site investigator, site coordinator, or other designee is responsible for responding to the 
queries in a timely manner, within the system, either by confirming the data as correct or 
updating the original entry, and providing the reason for the update (eg, data entry error). 
Original entries as well as any changes to data fields will be stored in the audit trail of the 
system. Regular oversight by the principal investigator of the data entered into the EDC system 
is expected to occur on an ongoing basis throughout the study to ensure quality and 
completeness. At a minimum, before any interim, final, or other time points (as instructed by 
Gilead), the investigator will apply his/her electronic signature to confirm that the forms have 
been reviewed and that the entries accurately reflect the information in the source documents. At 
the conclusion of the study, Gilead will provide the site investigator with a read-only archive 
copy of the data entered. This archive must be stored in accordance with the records retention 
requirements outlined in Section 9.1.6.
9.1.8.
Investigator Inspections
The investigator will make available all source documents and other records for this study to 
Gilead’s appointed study monitors, to IRB, or to regulatory authority or health authority 
inspectors.
9.1.9.
Protocol Compliance
The investigator is responsible for ensuring the study is conducted in accordance with the 
procedures and evaluations described in this protocol.

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9.2.
Sponsor Responsibilities
9.2.1.
Protocol Modifications
Protocol modifications, except those intended to reduce immediate risk to study participants, 
may be made only by Gilead. The investigator must submit all protocol modifications to the IRB 
in accordance with local requirements and receive documented IRB approval before 
modifications can be implemented.
9.2.2.
Study Reports and Publications
A clinical study report (CSR) will be prepared and provided to the regulatory agency(ies) when 
applicable and in accordance with local regulatory requirements. Gilead will ensure that the 
report meets the standards set out in the ICH Guideline for Structure and Content of Clinical 
Study Reports (ICH E3). Note that an abbreviated report may be prepared in certain cases. For 
studies with sites in countries following the EU Regulation No. 536/2014, a CSR will be 
submitted within 1 year (6 months for pediatric studies, in accordance with Regulation [EC] 
No. 1901/2006) after the global end of study (as defined in Section 3.4.2).
Investigators in this study may communicate, orally present, or publish study data in scientific 
journals or other scholarly media in accordance with the Gilead clinical trial agreement.
9.3.
Joint Investigator/Sponsor Responsibilities
9.3.1.
Payment Reporting
Investigators and their study personnel may be asked to provide services performed under this 
protocol (eg, attendance at investigator meetings). If required under the applicable statutory and 
regulatory requirements, Gilead will capture and disclose to federal and state agencies any 
expenses paid or reimbursed for such services, including any clinical study payments, meal 
and/or travel expenses or reimbursements, consulting fees, and any other transfer of value.
9.3.2.
Access to Information for Monitoring
In accordance with regulations and guidelines, the study monitor must have direct access to the 
investigator’s source documentation and any participant records in order to verify the adherence 
to the protocol and the accuracy of the data recorded in the eCRF. The study monitor is 
responsible for routine review of the eCRF at regular intervals throughout the study to verify 
adherence to the protocol and the completeness, consistency, and accuracy of the data being 
entered on them. The investigator agrees to cooperate with the study monitor to ensure that any 
problems detected through any type of monitoring (central, off-site, on-site) are resolved.

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9.3.3.
Access to Information for Auditing or Inspections
Representatives of regulatory authorities or Gilead may conduct inspections or audits of the 
clinical study. If the investigator is notified of an inspection by a regulatory authority, the 
investigator agrees to notify the Gilead study monitor immediately. The investigator agrees to 
provide to representatives of a regulatory agency or Gilead access to records, facilities, and 
personnel for the effective conduct of any inspection or audit.
9.3.4.
Study Discontinuation
Gilead reserves the right to terminate the study at any time, and the investigator has the right to 
terminate the study at his or her site. Should this be necessary, both parties will arrange 
discontinuation procedures and notify the participant, appropriate regulatory authority(ies), and 
IRB. In terminating the study, Gilead and the investigator will ensure that adequate consideration 
is given to the protection of the participants’ interests.
9.3.5.
Data Protection
Enterprise level technical and organizational controls have been developed at Gilead for the 
purpose of data protection. This includes user authentication and identification, fine grained 
access controls, end-to-end data encryption, security monitoring, network segregation, and 
physical security controls. Users of Gilead systems are provided training for security awareness 
and privacy. 
To prepare for the possibility of a data security breach, Gilead maintains a business continuity 
and disaster recovery plan and conducts regular disaster recovery testing to ensure that Gilead 
systems are recoverable if a cyber or data security incident is experienced. Gilead’s detailed 
incident response plan for any cyber or data security incident is based on the following 5 steps: 
detection, analysis, containment, eradication, and recovery. Gilead’s standard clinical trial 
agreement with study sites also includes data privacy language and arrangements in case of data 
security breaches as follows: 
Gilead and institutions will both act in accordance with the applicable data protection law. 
Furthermore, the study site and Gilead will cooperate with each other to take the necessary 
measures in order to comply with the applicable data protection law. Both Gilead and the study 
site shall implement appropriate technical and organizational measures to meet the requirements 
of the EU General Data Protection Regulation. If either party becomes aware of a personal data 
breach related to data processed under this agreement, that party shall promptly notify the other 
party. In such a case, parties will fully cooperate with each other to remedy the personal data 
breach and promptly fulfill the (statutory) notification obligations. A personal data breach refers 
to a personal data breach as described in Article 4, Article 33, and Article 34 of the EU General 
Data Protection Regulation and applicable national data protection laws.

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10.
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structural convergence of broad and potent HIV antibodies that mimic CD4 
binding. Science 2011;333 (6049):1633-7.
Sneller MC, Blazkova J, Justement JS, Shi V, Kennedy BD, Gittens K, et al. Combination anti-
HIV antibodies provide sustained virological suppression. Nature 2022;606 
(7913):375-81.
U. S. Department of Health and Human Services, Food and Drug Administration (FDA), Center 
for Drug Evaluation and Research (CDER). Human Immunodeficiency Virus-1 
Infection: Developing Antiretroviral Drugs for Treatment. Guidance for Industry. 
Silver Spring, MD.  November, 2015.
UNAIDS Joint United Nations Programme on HIV/AIDS. UNAIDS DATA 2023. 2023. 

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11.
APPENDICES

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11.1.
Investigator Signature Page
GILEAD SCIENCES, INC.
333 LAKESIDE DRIVE
FOSTER CITY, CA 94404
A Phase 2 Randomized, Open-label Study to Evaluate the Safety and Efficacy of Broadly 
Neutralizing Antibodies (bNAbs) GS-5423 and GS-2872 in Combination With the Capsid 
Inhibitor Lenacapavir as Long-Acting Treatment Dosed Every 6 Months in Virologically 
Suppressed Adults With HIV-1 Infection
Amendment 3: 13 May 2024
CLINICAL STUDY PROTOCOL ACKNOWLEDGMENT
INVESTIGATOR STATEMENT
I have read the protocol, including all appendices, and I agree that it contains all necessary 
details for me and my staff to conduct this study as described. I will conduct this study as 
outlined herein and will make a reasonable effort to complete the study within the time 
designated.
I will provide all study personnel under my supervision copies of the protocol and access to all 
information provided by Gilead Sciences, Inc. I will discuss this material with them to ensure 
that they are fully informed about the drugs and the study.
Principal Investigator Name (Printed)
Signature
Date
Site Number

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11.2.
Disaster and Public Health Emergency Risk Assessment and Mitigation Plan 
During an ongoing disaster or public health emergency (hereafter referred to as an “event”), 
potential risks associated with participants being unable to attend study visits have been 
identified for this study. 
These risks can be summarized as follows:
1) Study drug supplies to participants and sites:
a) Participants may be unable to return to the site to get the study drug, or the site may be 
unable to accept any participant visits. Without study drugs, the participant would not be 
able to continue receiving the study drug as planned per protocol.
Mitigation plan: study drug supplies may be provided to the participant from the site 
without a clinic visit, once it is confirmed that the participant may safely continue study 
drug as determined by the principal investigator. A remote study visit, via phone or video 
conferencing, must be performed before remote study drug resupply. At the earliest 
opportunity, the site will schedule in-person participant visits and return to the protocol’s 
regular schedule of study procedures. A qualified courier may be used to ship the study 
drug from sites to study participants if permitted by the local ethics 
committee/institutional review board/regulatory authority as applicable and with 
sponsor's approval.
b) Shipments of study drug could be delayed because of transportation issues. Without study 
drug, the participant would not be able to continue receiving the study drug as planned 
per protocol.
Mitigation plan: the site’s study drug inventory should be closely monitored. Site staff 
should notify the sponsor or delegate if they foresee shortage in study drug inventory or if 
there is any interruption in local shipping service. The sponsor will continue to monitor 
inventory at the study drug depot and investigational sites. Manual shipments will be 
triggered as necessary.
2) Participant safety monitoring and follow-up:
a) Participants may be unable or unwilling to come to the investigational site for their 
scheduled study visits as required per protocol.
Mitigation plan: For participants who may be unable or unwilling to visit the 
investigational site for their scheduled study visits as required per protocol, the principal 
investigator or qualified delegate will conduct a remote study visit, via phone or video 
conferencing, to assess the participant within the target visit window date whenever 
possible. During the remote study visit, the following information at minimum will be 
reviewed: 

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i)
Confirm if participant has experienced any adverse events (AEs)/serious adverse 
events (SAEs)/special situations (including pregnancy) and follow up on any 
unresolved AEs/SAEs.
ii) Review the current list of concomitant medications and document any new 
concomitant medications.
iii) If applicable, confirm electronic diary questionnaires and participant-reported 
outcomes have been completed and transmitted.
iv) If applicable, confirm the participant’s study drug supply is sufficient to last until the 
next planned visit date. If study drug resupply is needed, it will be provided as 
described above in (1).
v) If applicable, remind the participant to maintain current dosing and to keep all 
dispensed study drug kits for return at the next on-site visit.
b) Participants may be unable or unwilling to travel to the site for planned assessments 
(eg, safety blood draws); hence samples may not be sent for central laboratory analyses.
Mitigation plan: Local laboratories or other vendors may be utilized as appropriate to 
monitor participant safety until the participant can return to the site for their regular 
follow up per protocol. Any changes in the party conducting laboratory assessments for 
the study because of the event will be documented accordingly. Pregnancy testing may be 
performed using a home urine pregnancy test if local laboratory pregnancy testing is not 
feasible.
c) Participants may be unable or unwilling to attend the study visit to sign an updated 
informed consent form version.
Mitigation plan: The site staff will follow their approved consent process and remain in 
compliance with the local ethics committee/institutional review board and national laws 
and regulations. Remote consent will be allowed if has been approved by the local ethics 
committee/institutional review board. The consent process will be documented and 
confirmed by normal consent procedure at the earliest opportunity.
3) Protocol and monitoring compliance:
a) Protocol deviations may occur in case scheduled visits cannot be conducted as planned 
per protocol.
Mitigation plan: If it is not possible to complete a required procedure, an unscheduled 
visit should be conducted as soon as possible when conditions allow. The situation should 
be recorded and explained as a protocol deviation. Any missed participant visits or 
deviation to the protocol because of the event must be reported in the electronic case 
report form and described in the clinical study report (CSR). Any remote study visits that 

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are conducted in lieu of clinic visits because of the event will be documented as a 
protocol deviation related to the event.
b) Study monitors may be unable to carry out source data review or source data verification, 
or study drug accountability or assess protocol and Good Clinical Practice compliance. 
This may lead to delays in source data verification, an increase in protocol deviations, or 
underreporting of AEs.
Mitigation plan: The study monitor is to remain in close communication with the site to 
ensure data entry and query resolution. Remote source data verification may be arranged 
if allowed by local regulation and the Study Monitoring Plan. The study monitor is to 
reference the Study Monitoring Plan for guidance on how to conduct an off-site 
monitoring visit. The study staff is to save and document all relevant communication in 
the study files. The status of sites that cannot accept monitoring visits and/or participants 
on site, must be tracked centrally and updated on a regular basis.
4) Missing data and data integrity:
There may be an increased amount of missing data because of participants missing 
visits/assessments. This could have an impact on the analysis and the interpretation of 
clinical study data. 
Mitigation plan: Implications of a event on methodological aspects for the study will be 
thoroughly assessed and documented, and relevant actions will be taken as appropriate 
(eg, modification of the statistical analysis plan) and in compliance with regulatory 
authorities’ guidance. Overall, the CSR will describe the impact of the event on the 
interpretability of study data.
Risks will be assessed continuously, and temporary measures will be implemented to mitigate 
these risks as part of a mitigation plan, as described above. These measures will be 
communicated to the relevant stakeholders as appropriate and are intended to provide alternate 
methods that will ensure the evaluation and assessment of the safety of participants who are 
enrolled in this study. 
Since these potential risks are considered mitigated with the implementation of these measures, 
the expected benefit-risk assessment of the study drug(s) in study participants remains 
unchanged. 

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11.3.
Pregnancy Precautions, Definition of Childbearing Potential, and 
Contraceptive Requirements
1) Definitions
a. Definition of Childbearing Potential
For the purposes of this study, a participant assigned female at birth is considered of childbearing 
potential following the initiation of puberty (Tanner stage 2) until becoming postmenopausal 
unless the participant is permanently sterile or has medically documented ovarian failure.
Participants assigned female at birth are considered to be in a postmenopausal state when they 
are at least 54 years of age with cessation of previously occurring menses for at least 12 months 
without an alternative cause. In addition, participants assigned female at birth younger than 
54 years with amenorrhea of at least 12 months also may be considered postmenopausal if their 
follicle-stimulating hormone level is in the postmenopausal range and they are not using 
hormonal contraception or hormonal replacement therapy.
Permanent sterilization includes hysterectomy, bilateral oophorectomy, or bilateral 
salpingectomy in a participant assigned female at birth of any age.
b. Definition of Fertility in a Participant Assigned Male at Birth
For the purposes of this study, a participant assigned male at birth is considered fertile after the 
initiation of puberty unless the participant is permanently sterile by bilateral orchidectomy or 
medical documentation.
2)
Contraception Requirements for Participants Assigned Female at Birth and of 
Childbearing Potential
1) Study Drug Effects on Pregnancy and Hormonal Contraception
Lenacapavir (LEN) data on pregnant participants are limited or not available. Data from 
nonclinical toxicity studies of LEN have demonstrated no adverse effect on fertility or 
embryo-fetal development. Based on in vitro and in vivo drug-drug interaction liability 
assessment, a clinically significant drug-drug interaction with LEN and hormonal contraceptives 
is not expected; an oral contraception drug-drug interaction study was not done. Please refer to 
the latest version of the investigator’s brochure (IB) for additional information.
GS-5423 and GS-2872 data on pregnant participants are limited or not available. As per 
International Council for Harmonisation guidance, monoclonal antibodies directed at viral 
targets, such as GS-5423 and GS-2872, do not require reproductive toxicity studies. As protein 
biologics, GS-5423 and GS-2872 are unlikely to have human 
genotoxicity/teratogenicity/fetotoxicity. A reduction in the clinical efficacy of hormonal 
contraception is not expected as GS-5423 and GS-2872 are not cytokine modulators and not 
anticipated to affect the expression of cytochrome P450 enzymes. Please refer to the latest 
version of the IB for additional information.

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2) Contraception Requirements for Participants Assigned Female at Birth and of 
Childbearing Potential
The inclusion of participants assigned female at birth and of childbearing potential requires using 
at least an acceptable effective contraceptive measure. They must have a negative serum 
pregnancy test at screening and a negative pregnancy test on the Day 1 visit prior to the dose of 
study drugs. In the event of a delayed menstrual period (over 1 month between menstruations), a 
pregnancy test must be performed to rule out pregnancy. This is applicable also for participants 
assigned female at birth and of childbearing potential with infrequent or irregular periods. 
Pregnancy tests will be performed per the study procedures tables (Table 1 and Table 2).
Duration of required contraception for participants assigned female at birth and of childbearing 
potential enrolled in this clinical study should start from the screening visit until 6 months 
following last dose of study drug.
Participants assigned female at birth and of childbearing potential must agree to 1 of the 
following contraceptive methods:
•
Complete abstinence from intercourse of reproductive potential. Abstinence is an acceptable 
method of contraception only when it is in line with the participant’s preferred and usual 
lifestyle.
Or
Consistent and correct use of 1 of the following methods of birth control listed below:
•
Hormonal and nonhormonal intrauterine device
•
Bilateral tubal occlusion (upon medical assessment of surgical success)
•
Vasectomy in the partner assigned male at birth (upon medical assessment of surgical 
success)
Or
Participants assigned female at birth and of childbearing potential who initiate use of a hormonal 
contraceptive greater than 5 days after onset of menses as their method of birth control should 
use additional backup contraception (eg, condoms) for 7 days or avoid sexual intercourse for 
7 days. Hormonally based contraceptives or barrier methods permitted for use in this protocol are 
as follows:
•
Hormonal methods 
Oral contraceptives (either combined or progesterone only)
Injectable progesterone

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Subdermal contraceptive implant
Transdermal contraceptive patch
Contraceptive vaginal ring
•
Barrier methods 
Male condom (with or without spermicide)
Female condom (with or without spermicide)
Diaphragm with spermicide
Cervical cap with spermicide
Sponge with spermicide
Inclusion of methods of contraception in this list of permitted methods does not imply that the 
method is approved in any country or region. Methods should only be used if locally approved. 
Participants assigned female at birth and of childbearing potential must also refrain from egg 
donation and in vitro fertilization during treatment and until the end of contraception 
requirement.
3)
Contraception Requirements for Participants Assigned Male at Birth
No contraception measures are needed.
4)
Unacceptable Birth Control Methods
Birth control methods that are unacceptable include periodic abstinence (eg, calendar, ovulation, 
symptothermal, postovulation methods), withdrawal (coitus interruptus), spermicides only, and 
lactational amenorrhea method. A female condom and a male condom should not be used 
together.
5)
Procedures to Be Followed in the Event of Pregnancy
Participants assigned female at birth will be instructed to notify the investigator if they become 
pregnant or suspect they are pregnant at any time from start of the study until at least 700 days 
following the last dose of study drug. Study drug must be discontinued immediately.
Instructions for reporting pregnancy and pregnancy outcome are outlined in Section 7.4.2.3. 

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11.4.
Toxicity Grading Scale for Severity of Adverse Events and Laboratory 
Abnormalities
The Division of AIDS (DAIDS) Table for Grading the Severity of Adult and Pediatric Adverse 
Events, Corrected Version 2.1, July 2017. The DAIDS scale is available at the following 
location: https://rsc.niaid.nih.gov/sites/default/files/daidsgradingcorrectedv21.pdf 

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11.5.
Management of Clinical and Laboratory Adverse Events
AE = adverse event
Grade 1 
Continue study drug 
dosing at the discretion of 
the investigator 
Grnd, 31 r 
Grnd, 4 
Confirm toxicity grade of 
AE and/or repeat 
j 
laborat01y ~ssessment to ----+ 
confum tox1c1ty grade of 
laborat01y abn01mality 
l 
If confinned Grade 3 laborat01y abnonnality or 
AE, and possibly or probably refated 
If confumed and 
unrelated to study 
drng(s), dosing may 
continue at the 
to study drug(s): 
discretion of the 
1. Withhold study drug(s) until :S Grade 2 
investigator. 
2. Restait all study drng(s) at full dose upon 
discussion with Gilead Medical Monitor 
1 
If Grade 3 or 4 recurrence is 
confumed and possibly or 
probably related to study 
drng(s), discontinue all study 
drng(s) pe1manently, and manage 
the pmticipant according to local 
practice. 
1 
If Grade 3 or 4 recurrence is 
confumed and unrelated to study 
drng(s), continue all 
investigational medicinal 
product(s) at the same dose at the 
discretion of the investigator. 
If confinned Grade 4 
laborat01y abn01mality or 
AE, and possibly or 
probably related to study 
drug(s), discontinue study 
dosing pe1manently, a11d 
ma11age paitici pant 
according to local practice. 
Pmticipai1t should be 
followed as clinically 
indicated until the 
laborat01y abn01mality 
returns to baseline, or is 
otl1e1w ise explained. 

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11.6.
Country-Specific Requirements
Not applicable.

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11.7.
Amendment History
A high-level summary of amendment history is provided in tabular form below. Minor changes 
such as the correction of typographic errors, grammar, or formatting are not detailed.
A separate tracked change (red-lined) document comparing the previous version of the protocol 
to this amendment will be made available upon the publication of this protocol.
11.7.1.
Amendment 3 (13 May 2024)
Rationale for Key Changes Included in Amendment 3
Affected Sections
Updated the dosage and administration guidance to reflect coadministration 
option starting at Week 52 (in conjunction with sequential administration). 
Study Procedures Table 
(Tables 1 and 2), Sections 5.3 
and 6.3.6
Updated HIV reservoir assay to include peripheral blood mononuclear cells 
(PBMCs).
Study Procedures Table 
(Tables 1 and 2)
Sample collection guidance split into 2 footnotes for better clarity (HIV 
reservoir sample and electrocardiogram data in 1 footnote and biomarker 
samples [PBMC and plasma] in a separate footnote).
Study Procedures Table 
(Tables 1 and 2)
Updated wording in the risk assessment and risk mitigation plan to align with 
the current protocol template.
Section 1.5,  Appendix 11.2
Added details regarding management of virologic rebound.
Section 6.3.9.2
Removed details regarding Fisher exact test per decision of Biostatistics group.
Section 8.4
Added section on data protection requirements to align with the standard text 
in the current Gilead protocol template.
Section 9.3.5
Minor editorial and formatting changes.
Throughout, as needed
CCI

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11.7.2.
Amendment 2 (26 June 2023)
Rationale for Key Changes Included in Amendment 2
Affected Sections
Emerging data from Study GS-US-536-5816 suggest a higher rate of virologic 
rebound in participants assigned to the GS-2872 10 mg/kg group; therefore, 
Treatment Group 2 was removed, leading to changes in dosage information 
and the statistical analysis plan including sample size.
Synopsis, Study Schema, Study 
Procedures Table, Sections 1, 
2, 3, 4, 5, 6, 8
The number of study centers increased from 50 to 55.
Synopsis
Updated the window period of the PK sampling for study drugs to 
≤ 30 minutes prior to dosing of oral LEN for consistency.
Study procedures Table 1 
(footnote ‘o’) and Section 
6.3.6.1
Clarified that HIV-1 sensitivity results from screening or from the Study 
GS-US-536-5816 within 36 months prior to Screening Visit 2 meeting specific 
criteria will be considered for the inclusion in the study.
Section 4.2
Aligned the screening visit (Screening Visit 2) as per the study procedure 
tables for the study assessments for eligibility.
Synopsis, Sections 4.2 and 4.3
Updated the background information for GS-5423 and GS-2872 to include 
their synonyms ‘zinlirvimab’and ‘teropavimab’ respectively.
Sections 1.2.2.1 and 1.2.3.1
Updated the language to clarify that the data from the DMC analysis and/or 
primary analysis will not be considered for the extension phase dose selection.
Synopsis, Study Schema 
(footnote a), Table 3 and 4 
(footnote a), Sections 3.1.2, 5.3
Updated background information with respect to clinical studies of lenacapavir 
with GS-5423 and GS-2872.
Section 1.2.4
Clarified that the participants in Treatment Group 1 who reach Week 52 and 
meet criteria to enter the extension phase will receive the study regimen every 
26 weeks during the extension phase.
Section 5.3, Table 3 footnote
Updated to clarify that a plasma sample from the confirmation visit will be the 
primary sample used for HIV-1 PR, RT, and IN genotypic and phenotypic 
testing.
Section 6.3.9
Minor changes to correct typographic errors, language, and to provide 
clarifications.
Throughout, as needed

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11.7.3.
Amendment 1 (18 January 2023)
Rationale for Key Changes Included in Amendment 1
Affected Sections
Instructions for management of ISRs persisting for more than 26 weeks were 
revised to clarify that ISRs lasting longer than 26 weeks will be followed 
clinically until resolution or study completion, and the time of resolution will be 
documented.
Section 7.7.1
Instructions for the management of ophthalmologic symptoms were added.
Section 7.7.2
Dosing and administration instructions for the handling of missed or delayed 
dosing were added for the cases that more than 28 weeks have passed since the 
last study drug dose.
Section 5.3.2
A footnote was added to clarify that participants eligible for the extension phase 
may opt to continue study visits beyond the last week listed under the Extension 
Phase column in the Study Procedures Table (Week 156), consistent with 
Section 3.2.
Study Procedures Table
Minor changes to correct typographic errors and clarifications.
Throughout, as needed

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11.8.
Sponsor Signature Page
GILEAD SCIENCES, INC.
333 LAKESIDE DRIVE
FOSTER CITY, CA 94404
A Phase 2 Randomized, Open-label Study to Evaluate the Safety and Efficacy of Broadly 
Neutralizing Antibodies (bNAbs) GS-5423 and GS-2872 in Combination With the Capsid 
Inhibitor Lenacapavir as Long-Acting Treatment Dosed Every 6 Months in Virologically 
Suppressed Adults With HIV-1 Infection
Protocol Amendment 3: 13 May 2024
APPROVAL OF CLINICAL STUDY PROTOCOL
This protocol has been approved by Gilead Sciences, Inc. The following signature documents 
this approval. 
[See appended electronic signature]
Senior Associate Clinical Development 
Director, Virology
Signature
[See appended electronic signature]
Date
PPD

Protocol GS-US-536-5939 Amd 3.0
ELECTRONIC SIGNATURES
Signed by
Meaning of Signature
Server Date
(dd-MMM-
yyyy hh:mm:ss)
Clinical Development
eSigned
09-May-2024
16:41:26
PPD