A Phase 1a/1b Study to Evaluate the Safety and Tolerability of Repeated Doses of Nonreplicating Arenavirus Vector Therapeutic Vaccines GS-2829 and GS-6779 in Healthy Participants and Participants With Chronic Hepatitis B (CHB)
Phase: PHASE1
Conditions: Chronic Hepatitis B
Sponsor: Gilead Sciences

CLINICAL STUDY PROTOCOL
Study Title:
A Phase 1a/1b Study to Evaluate the Safety and Tolerability of 
Repeated Doses of Nonreplicating Arenavirus Vector Therapeutic 
Vaccines GS-2829 and GS-6779 in Healthy Participants and 
Participants With Chronic Hepatitis B (CHB)
Short Title:
Study of HBV Therapeutic Vaccines GS-2829 and GS-6779 in 
Healthy Participants and Participants With Chronic Hepatitis B
Sponsor:
Gilead Sciences, Inc.
333 Lakeside Drive
Foster City, CA 94404
USA
IND Number:
Not Applicable
EudraCT Number:
Not Applicable
ClinicalTrials.gov ID:
NCT05770895
Indication:
Chronic Hepatitis B (CHB)
Protocol ID:
GS-US-642-5670
Contact Information:
The medical monitor name and contact information will be 
provided on the Key Study Team Contact List.
Protocol Version/Date:
Original:
01 September 2022
Amendment 1:
22 November 2022
Amendment 2:
20 July 2023
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.
(r) GILEAU 

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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The information contained in this document, particularly unpublished data, is the property or 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
GLOSSARY OF ABBREVIATIONS AND DEFINITION OF TERMS ......................................................................7
PROTOCOL SYNOPSIS................................................................................................................................................9
STUDY SCHEMA........................................................................................................................................................15
STUDY PROCEDURES TABLES ..............................................................................................................................18
1.
INTRODUCTION................................................................................................................................................32
1.1.
Background..............................................................................................................................................32
1.2.
Background on Investigational Product ..................................................................................................33
1.2.1.
GS-2829 and GS-6779 ..........................................................................................................34
1.2.2.
Information About Comparator (Placebo).............................................................................35
1.2.3.
Information About Auxiliary Medicinal Products ................................................................35
1.3.
Rationale for This Study..........................................................................................................................36
1.4.
Rationale for the Dose Selection of the Investigational Product.............................................................37
1.5.
Risk/Benefit Assessment for the Study ...................................................................................................37
1.6.
Compliance..............................................................................................................................................39
2.
OBJECTIVES AND ENDPOINTS......................................................................................................................40
3.
STUDY DESIGN.................................................................................................................................................41
3.1.
Study Design ...........................................................................................................................................41
3.1.1.
Safety Review Team and Charter..........................................................................................43
3.2.
Duration of Dosing..................................................................................................................................43
3.3.
Protocol-Specific Discontinuation Criteria .............................................................................................44
3.3.1.
Criteria for Early Discontinuation for the Individual Participant From the 
Investigational Product..........................................................................................................45
3.3.2.
Criteria for Early Discontinuation for the Individual Participant From the 
Study......................................................................................................................................45
3.3.3.
Criteria for Early Discontinuation of a Cohort (Stopping Rules)..........................................46
3.3.4.
Criteria for Early Termination of the Study ..........................................................................47
3.3.5.
Reporting a Loss to Follow-Up .............................................................................................47
3.4.
Definitions for Time of Primary Endpoint and End of Study .................................................................47
3.4.1.
Primary Endpoint...................................................................................................................47
3.4.2.
End of Study..........................................................................................................................47
3.5.
Source Data .............................................................................................................................................47
4.
PARTICIPANT POPULATION..........................................................................................................................48
4.1.
Number of Participants and Participant Selection...................................................................................48
4.1.1.
Participant Replacement........................................................................................................48
4.2.
Phase 1a Healthy Participant Inclusion/Exclusion Criteria.....................................................................48
4.2.1.
Inclusion Criteria...................................................................................................................48
4.2.2.
Exclusion Criteria..................................................................................................................49
4.3.
Phase 1b Virally Suppressed CHB Participant Inclusion/Exclusion Criteria .........................................51
4.3.1.
Inclusion Criteria...................................................................................................................51
4.3.2.
Exclusion Criteria..................................................................................................................52
5.
STUDY INTERVENTIONS AND CONCOMITANT MEDICATIONS ...........................................................55

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5.1.
Randomization, Blinding, and Treatment Code Access..........................................................................55
5.1.1.
Randomization.......................................................................................................................55
5.1.2.
Blinding .................................................................................................................................55
5.1.3.
Procedures for Breaking the Blind on Treatment Codes.......................................................56
5.2.
Description and Handling of the Investigational Product .......................................................................56
5.2.1.
Formulation ...........................................................................................................................56
5.2.2.
Packaging and Labeling ........................................................................................................56
5.2.3.
Storage and Handling ............................................................................................................56
5.3.
Dosage and Administration .....................................................................................................................57
5.4.
Fasting and Meals....................................................................................................................................57
5.5.
Dispensing, Accountability, and Disposal or Return of Investigational Products ..................................58
5.6.
Concomitant Medications and Other Protocol Restrictions ....................................................................59
5.6.1.
Concomitant Medications......................................................................................................59
5.6.2.
Other Protocol Restrictions ...................................................................................................60
6.
STUDY ASSESSMENTS....................................................................................................................................61
6.1.
Informed Consent ....................................................................................................................................61
.............................................................................61
6.2.
Participant Enrollment and Treatment Assignment ................................................................................62
6.3.
Instructions for Study Procedures ...........................................................................................................62
6.3.1.
Adverse Events......................................................................................................................62
6.3.2.
Screening Assessments..........................................................................................................62
6.3.3.
Treatment Assessments .........................................................................................................63
6.3.4.
Participant Diaries for Reactogenicity...................................................................................63
6.3.5.
Clinical Virology...................................................................................................................63
6.3.6.
Sample Collection for Biomarker Evaluation .......................................................................64
6.4.
Safety Assessments .................................................................................................................................65
6.4.1.
Electrocardiogram Assessment .............................................................................................65
6.4.2.
Physical Examination ............................................................................................................65
6.4.3.
Vital Signs .............................................................................................................................66
6.4.4.
Body Mass Index...................................................................................................................66
6.4.5.
Clinical Laboratory Tests/Assessments.................................................................................66
6.4.6.
Creatinine Clearance .............................................................................................................69
6.4.7.
Concomitant Medications/Protocol Restrictions...................................................................69
6.5.
Posttreatment Assessments......................................................................................................................69
6.6.
Assessments for Early Discontinuation From Investigational Product or From the Study.....................69
6.6.1.
Assessments for End of Study...............................................................................................69
6.7.
Sample Storage........................................................................................................................................70
7.
ADVERSE EVENTS AND TOXICITY MANAGEMENT................................................................................71
7.1.
Definitions of Adverse Events and Serious Adverse Events...................................................................71
7.1.1.
Adverse Events......................................................................................................................71
7.1.2.
Serious Adverse Events.........................................................................................................71
7.1.3.
Investigational Products and Gilead Concomitant Therapy Special 
Situation Reports...................................................................................................................72
7.2.
Assessment of Adverse Events and Serious Adverse Events..................................................................73
7.2.1.
Assessment of Causality for Investigational Products and Procedures.................................73
7.2.2.
Assessment of Severity..........................................................................................................73
7.3.
Investigator Reporting Requirements and Instructions ...........................................................................74
7.3.1.
Requirements for Collection Prior to Investigational Product Initiation...............................74
7.3.2.
Adverse Events......................................................................................................................74
7.3.3.
Serious Adverse Events.........................................................................................................74
7.3.4.
Investigational Product Special Situations Reports...............................................................74
7.3.5.
Concomitant Therapy Reports...............................................................................................75
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7.4.
Reporting Process for Serious Adverse Events and Special Situations Reports.....................................75
7.4.1.
Serious Adverse Event Reporting Process ............................................................................75
7.4.2.
Special Situations Reporting Process ....................................................................................76
7.5.
Gilead Reporting Requirements ..............................................................................................................78
7.6.
Clinical Laboratory Abnormalities and Other Abnormal Assessments as Adverse Events or 
Serious Adverse Events...........................................................................................................................78
7.7.
Toxicity Management..............................................................................................................................78
7.7.1.
Grades 1 and 2 Laboratory Abnormality or Clinical Event ..................................................79
7.7.2.
Grades 3 Laboratory Abnormality or Clinical Event ............................................................79
7.7.3.
Grades 4 Laboratory Abnormality or Clinical Event ............................................................79
7.7.4.
Management of ALT Elevation or Flare ...............................................................................80
7.7.5.
Potential Immune-mediated Adverse Events on Study.........................................................81
8.
STATISTICAL CONSIDERATIONS.................................................................................................................82
8.1.
Analysis Objectives and Endpoints.........................................................................................................82
8.2.
Planned Analyses.....................................................................................................................................82
8.2.1.
Interim Analysis ....................................................................................................................82
8.2.2.
Final Analysis........................................................................................................................82
8.3.
Analysis Conventions..............................................................................................................................82
8.3.1.
Analysis Sets .........................................................................................................................82
8.3.2.
Data Handling Conventions ..................................................................................................83
8.4.
Demographic Data and Baseline Characteristics Analysis .....................................................................83
8.5.
Safety Analysis........................................................................................................................................83
8.5.1.
Extent of Exposure ................................................................................................................83
8.5.2.
Adverse Events......................................................................................................................84
8.5.3.
Laboratory Evaluations .........................................................................................................84
8.5.4.
Other Safety Evaluations.......................................................................................................85
8.6.
Pharmacodynamic Biomarker Analysis (Immunogenicity) ....................................................................85
8.7.
Other Exploratory Biomarker Analyses ..................................................................................................85
8.8.
Sample Size .............................................................................................................................................85
9.
RESPONSIBILITIES...........................................................................................................................................86
9.1.
Investigator Responsibilities ...................................................................................................................86
9.1.1.
Good Clinical Practice...........................................................................................................86
9.1.2.
Financial Disclosure ..............................................................................................................86
9.1.3.
Independent Ethics Committee Review and Approval .........................................................86
9.1.4.
Informed Consent ..................................................................................................................86
9.1.5.
Confidentiality.......................................................................................................................87
9.1.6.
Study Files and Retention of Records ...................................................................................87
9.1.7.
Case Report Forms ................................................................................................................88
9.1.8.
Investigator Inspections.........................................................................................................89
9.1.9.
Protocol Compliance .............................................................................................................89
9.2.
Sponsor Responsibilities .........................................................................................................................89
9.2.1.
Protocol Modifications ..........................................................................................................89
9.2.2.
Study Reports and Publications.............................................................................................89
9.3.
Joint Investigator/Sponsor Responsibilities ............................................................................................90
9.3.1.
Payment Reporting ................................................................................................................90
9.3.2.
Access to Information for Monitoring...................................................................................90
9.3.3.
Access to Information for Auditing or Inspections ...............................................................90
9.3.4.
Study Discontinuation ...........................................................................................................91
10.
REFERENCES.....................................................................................................................................................92
11.
APPENDICES......................................................................................................................................................95

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11.1.
Investigator Signature Page.....................................................................................................................96
11.2.
Authorization Status of Study Interventions ...........................................................................................97
11.3.
Pandemic Risk Assessment and Mitigation Plan ....................................................................................98
11.4.
Pregnancy Precautions, Definition of Childbearing Potential, and Contraceptive Requirements ........101
11.5.
Management of Clinical and Laboratory Adverse Events ....................................................................105
11.6.
Toxicity Grading Scale for Severity of Adverse Events and Laboratory Abnormalities......................106
11.7.
Potential Immune-mediated Conditionsa...............................................................................................107
11.8.
Country-Specific Requirements ............................................................................................................111
11.9.
Amendment History ..............................................................................................................................112
11.9.1.
Amendment 2 (20 July 2023)..............................................................................................112
11.9.2.
Amendment 1 (23 November 2022)....................................................................................113
11.10. Sponsor Signature Page.........................................................................................................................114
LIST OF IN-TEXT TABLES
Table 1.
Schedule of Assessments, Phase 1a – Cohorts 1 and 2 (Two Total Doses)............................18
Table 2.
Schedule of Assessments, Phase 1a – Cohorts 3, 4 and Phase 1b - Cohorts 5 and 6 
(Four Total Doses)...................................................................................................................21
Table 3.
Schedule of Assessments, Phase 1a – Cohort 8 and Phase 1b - Cohort 7 (Six Total 
Doses) ......................................................................................................................................25
Table 4.
Sampling for Biomarker Assessments for Phase 1a – Cohorts 1 and 2 (Two Total 
Doses) ......................................................................................................................................29
Table 5.
Sampling for Biomarker Assessments for Phase 1a – Cohorts 3 and 4 and Phase 1b - 
Cohorts 5 and 6 (Four Total Doses) ........................................................................................30
Table 6.
Sampling for Biomarker Assessments for Phase 1a – Cohort 8 and Phase 1b - 
Cohort 7 (Six Total Doses)......................................................................................................31
Table 7.
Study Objectives and Endpoints..............................................................................................40
Table 8.
Investigational Product Dose Timing......................................................................................44
Table 9.
Prohibited and Cautionary Medications ..................................................................................59
Table 10.
Laboratory Analytes ................................................................................................................67
Table 11.
ALT Elevation Monitoring and Toxicity Management...........................................................81
LIST OF IN-TEXT FIGURES
Figure 1.
Overall Study Schema, Phase 1a and Phase 1b.......................................................................15
Figure 2.
Schema for Cohorts 1 and 2 (Two Total Doses) .....................................................................16
Figure 3.
Schema for Cohorts 3, 4, 5, and 6 (Four Total Doses)............................................................16
Figure 4.
Schema for Cohorts 7 and 8 (Six Total Doses) .......................................................................17

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GLOSSARY OF ABBREVIATIONS AND DEFINITION OF TERMS
AE
adverse event
ALP
alkaline phosphatase
ALT
alanine aminotransferase
AST
aspartate aminotransferase
AxMP
auxiliary medicinal product
BMI
body mass index
CD4
clusters of differentiation 4
CD8
clusters of differentiation 8
CFR
Code of Federal Regulations
CHB
chronic hepatitis B
CK
creatine kinase
CLcr
creatinine clearance
CMV
cytomegalovirus
CTCAE
Common Terminology Criteria for Adverse Events
DNA
deoxyribonucleic acid
ECG
electrocardiogram
eCRF
electronic case report form
EDC
electronic data capture
ELISpot
enzyme-linked immunospot assay
ESLD
end-stage liver disease
ET
early termination
EU
European Union
EudraCT
European Clinical Trials Database
FDA
Food and Drug Administration
FFU
focus-forming unit
GCP
Good Clinical Practice
GGT
gamma-glutamyl transferase
Gilead
Gilead Sciences/Gilead Sciences, Inc.
GLP
Good Laboratory Practice
HAV
hepatitis A virus
HBcrAg
hepatitis B core-related antigen
HBeAb
hepatitis B e antibody
HBeAg
hepatitis B e antigen
HBsAb
hepatitis B surface antibody
HBsAg
hepatitis B surface antigen
HBV
hepatitis B virus
HCC
hepatocellular carcinoma
HCV
hepatitis C virus
HDV
hepatitis D virus
HEPES
N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid
HEV
hepatitis E virus

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HIV
human immunodeficiency virus
HIV-1
human immunodeficiency virus type 1
IB
investigator’s brochure
ICF
informed consent form
ICH
International Council for Harmonisation (of Technical Requirements for 
Pharmaceuticals for Human Use)
IEC
independent ethics committee
IFN
interferon
IFN-γ
interferon gamma
Ig
immunoglobulin
IND
investigational new drug
INR
international normalized ratio
IRT
Interactive Response Technology
LCMV
lymphocytic choriomeningitis virus
LLOQ
lower limit of quantification
MedDRA
Medical Dictionary for Regulatory Activities
NA
nucleos(t)ide analogues
PBMC
peripheral blood mononuclear cell
PBO
placebo
PCR
polymerase chain reaction
PICV
Pichinde virus
PIMMC
potential immune-mediated condition
PS
Patient Safety
PT
preferred term
QT (interval)
electrocardiographic interval between the beginning of the Q wave and termination of 
the T wave, representing the time for both ventricular depolarization and 
repolarization to occur
rHSA
recombinant human serum albumin
rLCMV
replication-deficient lymphocytic choriomeningitis virus
RNA
ribonucleic acid
SAE
serious adverse event
SARS-CoV-2
severe acute respiratory syndrome coronavirus 2
SRT
Safety Review Team
SSR
special situation report
SUSAR
suspected unexpected serious adverse reaction
TEAE
treatment-emergent adverse event
ULN
upper limit of normal
US, USA
United States, United States of America

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PROTOCOL SYNOPSIS
Gilead Sciences, Inc.
333 Lakeside Drive
Foster City, CA 94404
USA
Study Title: A Phase 1a/1b Study to Evaluate the Safety and Tolerability of Repeated Doses 
of Nonreplicating Arenavirus Vector Therapeutic Vaccines GS-2829 and GS-6779 in Healthy 
Participants and Participants With Chronic Hepatitis B (CHB)
Short Title: Study of HBV Therapeutic Vaccines GS-2829 and GS-6779 in Healthy 
Participants and Participants With Chronic Hepatitis B
IND Number: Not Applicable
EudraCT Number: Not Applicable
ClinicalTrials.gov Identifier: NCT05770895
Study Centers Planned: This is a multicenter study to be conducted at 1 site in New Zealand 
for Phase 1a activities and approximately 15 sites globally for Phase 1b activities.
Objectives and Endpoints:
Primary Objective
Primary Endpoint
•
To evaluate the safety and tolerability of repeated 
dosing of GS-2829 and GS-6779 in healthy 
participants and in virally suppressed participants 
with CHB
•
Proportion of participants with treatment-
emergent adverse events (AEs), serious adverse 
events (SAEs), and laboratory abnormalities 
Secondary Objective
Secondary Endpoints
•
To evaluate the immunogenicity of repeated 
dosing of GS-2829 and GS-6779 in healthy 
participants and in virally suppressed participants 
with CHB
•
Incidence and magnitude of vaccine-induced 
T-cell responses
Study Design:
This protocol is a blinded, placebo-controlled, randomized Phase 1a and Phase 1b study to 
evaluate the safety, tolerability, and immunogenicity of repeated doses of GS-2829 and 
GS-6779 administered by intramuscular injection in healthy participants (Phase 1a) and 
participants with CHB (Phase 1b). The study will comprise 8 cohorts, which will enroll up to 
10 participants each, with a 4:1 randomization to either the active viral vectors GS-2829 
and/or GS-6779 or placebo (PBO).
An overview of the study design is described below and shown in Figure 1, Figure 2, Figure 3, 
and Figure 4.

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The investigational products GS-2829 and GS-6779 are available as ≥ 1.0  107 focus-forming 
units (FFU)/mL. There are 2 doses in this study: high dose (0.5 mL of the undiluted solution) 
and low dose (0.5 mL of the 10-fold dilution of the high dose).
Following completion of screening, eligible participants will be randomized to receive the 
investigational product (viral vector or PBO) as shown below:
Phase 1a Healthy Participant Cohorts
•
Cohort 1 – Single low dose of GS-2829 or PBO on Day 1 and Day 57.
•
Cohort 2 – Single low dose of GS-6779 or PBO on Day 1 and Day 57.
•
Cohort 3 – Single low dose of GS-2829 or PBO on Day 1 and Day 57; and single low dose 
of GS-6779 or PBO on Day 29 and Day 85.
•
Cohort 4 – Single high dose of GS-2829 or PBO on Day 1 and Day 57; and single high 
dose of GS-6779 or PBO on Day 29 and Day 85.
•
Cohort 8 – Single high dose of GS-2829 or PBO on Day 1, Day 57, and Day 113; and 
single high dose of GS-6779 or PBO on Day 29, Day 85, and Day 141.
Phase 1b Virally Suppressed CHB Participant Cohorts
•
Cohort 5 – Single low dose of GS-2829 or PBO on Day 1 and Day 57; and single low dose 
of GS-6779 or PBO on Day 29 and Day 85.
•
Cohort 6 – Single high dose of GS-2829 or PBO on Day 1 and Day 57; and single high 
dose of GS-6779 or PBO on Day 29 and Day 85.
•
Cohort 7 – Single high dose of GS-2829 or PBO on Day 1, Day 57, and Day 113; and 
single high dose of GS-6779 or PBO on Day 29, Day 85, and Day 141.
Cohorts 1, 2, and 3
Cohorts 1 and 2 will enroll concurrently and will receive investigational product in 2 groups, a 
sentinel group (2 active and 1 PBO, randomly assigned) and the remainder (6 active and 1 
PBO), for a total of approximately 10 healthy participants per cohort. Dosing the remainder of 
Cohorts 1 and 2 and initiation of Cohort 3 will commence at the discretion of the investigator 
in consultation with the sponsor’s medical monitor upon evaluation of available safety data 
through at least 14 days after the first dose of investigational product in Cohort 1 and 2 
sentinel participants. The duration of this review period may be increased based on emerging 
preliminary safety data. Decisions to initiate a higher dose level cohort and any required 
revisions to postdose monitoring will be made upon the review of all available safety data by 
the Safety Review Team (SRT).
Cohorts 4 and 5
Initiation of Cohorts 4 and 5, which will run concurrently, will be determined at the discretion 
of the SRT based on the evaluation of available safety data through Day 43 (14 Days after the 
initial dose of both investigational products for all participants enrolled in Cohort 3), in 
addition to all available safety data from Cohorts 1 and 2. The decision on cohort initiation 
will be based on prespecified criteria agreed upon by the SRT and documented in the SRT 

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charter. The duration of this review period may be increased based on the emerging and 
cumulative safety data.
Cohort 8
Initiation of Cohort 8 will be determined at the discretion of the SRT based on the evaluation 
of available safety data through Day 43 (14 days after all participants in Cohort 3 have 
completed the initial dose of both investigational products), in addition to all available safety 
data from prior cohorts. Initiation of a third dose of 2-vector combination, therapy will be 
determined at the discretion of the SRT based on the evaluation of the available safety data 
through Day 99 (14 days after all participants in Cohort 4 have completed the second dose of 
both investigational products), in addition to all available safety data. The decision on cohort 
initiation will be based on prespecified criteria agreed upon by the SRT and documented in the 
SRT charter. The duration of this review period may be increased based on the emerging and 
cumulative safety data. 
Cohort 6
Initiation of Cohort 6 will be determined at the discretion of the SRT based on the evaluation 
of available safety data through Day 43 (14 days after initial dose of both the investigational 
products for all participants enrolled in Cohort 4), available safety data from participants 
enrolled in Cohort 5, and all available safety data from all dosed cohorts, and dosing will be 
initiated only in the absence of dose-limiting toxicity and/or meeting any prespecified stopping 
criteria. The duration of this review period may be increased based on the emerging and 
cumulative safety data.
Cohort 7
Initiation of Cohort 7 will be determined at the discretion of the SRT based on the evaluation 
of available safety data through Day 43 (14 days after initial dose of both the investigational 
products for all participants enrolled in Cohort 4), available safety data from participants 
enrolled in Cohort 5, and all available safety data from all dosed cohorts. Initiation of the third 
dose of 2 vector combination therapy will be determined at the discretion of SRT based on the 
evaluation of the available safety data through Day 99 (14 days after all participants in Cohort 
4 have completed the second dose of both investigational products), in addition to all available 
safety data. The decision on cohort initiation will be based on prespecified criteria agreed upon 
by the SRT and documented in the SRT charter. The duration of this review period may be 
increased based on the emerging and cumulative safety data.
Number of Participants Planned: Approximately 80 participants are planned for 8 cohorts. 
of 10 participants each: 50 healthy participants for Phase 1a activities and 30 participants 
diagnosed with CHB for Phase 1b activities.

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Target Population: 
Phase 1a: Healthy male and nonpregnant, nonlactating female participants, aged 18 through 
60 years, inclusive
Phase 1b: Male and nonpregnant, nonlactating female participants diagnosed with CHB, aged 
18 through 65 years, inclusive
Duration of Intervention:
•
Cohorts 1 and 2 will receive 2 total doses over 56 days (Days 1 and 57).
•
Cohorts 3, 4, 5, and 6 will receive 4 total doses over 84 days (Days 1, 29, 57, and 85).
•
Cohorts 7 and 8 will receive 6 total doses over 140 days (Days 1, 29, 57, 85, 113, and 
141).
•
All participants will be followed for safety for 24 weeks following their last dose of 
investigational product (through Day 225 for Cohorts 1 and 2; through Day 253 for 
Cohorts 3, 4, 5, and 6; and Day 309 for Cohorts 7 and 8).
Diagnosis and Main Eligibility Criteria:
Phase 1a: Eligible participants will include those assigned male sex at birth or those who are 
nonpregnant, nonlactating, assigned female at birth, aged 18 through 60 years inclusive, with a 
body mass index (BMI) of ≤ 32.0 kg/m2, with normal or nonclinically significant 12-lead 
electrocardiogram (ECG) evaluations, and no significant medical history. Participants will also 
be in good general health as determined by the investigator and have no prior history of 
hepatitis B virus (HBV) infection as demonstrated with a negative hepatitis B surface antigen 
(HBsAg) and hepatitis B core antibody test. Participants are prohibited from receipt of any 
investigational product or vaccine within 3 months of screening (with the exception of 
influenza and SARS-CoV-2 vaccines, which if needed, should be administered at least 14 days 
before or after an investigational product administration; participants should be encouraged to 
receive any needed vaccinations prior to enrollment) and should not receive ongoing therapy 
with any prohibited medications listed in the protocol.
Phase 1b: Eligible participants will include those assigned male sex at birth or those who are 
nonpregnant, nonlactating, assigned female at birth, aged 18 through 65 years, inclusive, with 
a BMI of ≤ 32.0 kg/m2, and with normal or nonclinically significant 12-lead ECG evaluations. 
Participants must have documented evidence of CHB based on one of the following: positive 
HBsAg or HBV DNA at least 6 months prior to the screening visit; or historical liver biopsy 
consistent with CHB infection. Participants must have no evidence of advanced fibrosis by 
FibroScan. Participants are prohibited from receipt of any investigational product or vaccine 
within 3 months of screening (with the exception of influenza and SARS-CoV-2 vaccines, 
which, if needed, should be administered at least 14 days before or after an investigational 
product administration; participants should be encouraged to receive any needed vaccinations 
prior to enrollment) and should not receive ongoing therapy with any prohibited medications 
listed in the protocol.

GS-2829 and GS-6779
Protocol GS-US-642-5670
Final
Gilead Sciences, Inc.
Amendment 2
CONFIDENTIAL
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Phase 1b participants in Cohorts 5, 6, and 7 must be receiving an approved HBV-active oral 
antiviral agent for ≥ 6 months prior to screening with HBV DNA less than the lower limit of 
quantification (LLOQ) for ≥ 3 months prior to screening with no plan to stop HBV-active 
antivirals during the study.
Study Procedures/Frequency:
All participants will provide informed consent, complete all screening procedures and 
assessments, and must meet all eligibility criteria prior to administration of investigational 
product on Day 1. 
Study procedures including investigational product administration, safety follow-up via 
collection of AEs, laboratory assessments, participant diary review, immunogenicity, and 
biomarker assessments, HBV genomic sequencing and phenotyping, and other procedures are 
described in the protocol Sections 5 and 6 and the scheduling and frequency of these 
procedures are detailed in the study assessment tables (Table 1, Table 2, and Table 3).
Test Product, Dose, and Mode of Administration:
GS-2829 – Low-dose intramuscular administration will be ≥ 0.5  106 FFU
GS-6779 – Low-dose intramuscular administration will be ≥ 0.5  106 FFU
GS-2829 – High-dose intramuscular administration will be ≥ 0.5  107 FFU
GS-6779 – High-dose intramuscular administration will be ≥ 0.5  107 FFU
Reference Therapy, Dose, and Mode of Administration:
The comparator will be an inactive PBO comprising a solution of human serum albumin with 
visual characteristics similar to the investigational products to be administered intramuscularly 
at the same volume as the investigational products.
Statistical Methods:
All analyses and summaries will be presented by population and treatment group. Data from 
participants who receive PBO may be pooled across cohorts within the same population.
The AE data will be listed by participant. The incidence of treatment-emergent AEs, SAEs, 
and AEs leading to discontinuation of investigational product will be summarized by 
treatment, system organ class, high-level term (if applicable), and preferred term using the 
current version of the MedDRA.
Listings of individual participant laboratory results will be provided. Laboratory results and 
change from baseline values for selected laboratory tests will be summarized by scheduled 
visits. The incidence of treatment-emergent laboratory abnormalities will be summarized by 
population and treatment.
Vital signs and ECG data will be summarized by population, treatment group, and visit.
The immunogenicity analysis will be based on the proportion of participants with 
investigational product-induced HBV-specific T-cell response, as determined by the interferon 

GS-2829 and GS-6779
Protocol GS-US-642-5670
Final
Gilead Sciences, Inc.
Amendment 2
CONFIDENTIAL
Page 14
20 July 2023
gamma (IFN-γ) enzyme-linked immunospot assay (ELISpot) assay and will be summarized by 
population and treatment group. The magnitude of the total investigational product-induced 
HBV-specific T-cell response, as determined by the IFN-γ ELISpot assay, will be summarized 
by population and treatment group.
Sample Size:
The sample size in this study is determined based on practical considerations and empirical 
experience with similar types of studies. No formal power and sample size calculation were 
performed. Overall, a total sample size of approximately 80 participants (10 participants 
per cohort, including 8 active and 2 PBO) is expected to provide a suitable assessment of the 
safety, tolerability, and immunogenicity of treatment with the investigational product.

GS-2829 and GS-6779 
Protocol GS-US-642-5670 
Gilead Sciences, Inc. 
STUDY SCHEMA 
Figure 1. 
Overall Study Schema, Phase la and Phase lb 
Cohort 1•: 
Low doses of 
GS-2829 0< 
Placebo In HP 
Cohor12•: 
Low doses of 
GS-6779 0< 
Placebo In HP 
t Total : doses 
+ Total 4 doses 
• Total of6 doses 
Cohort:3': 
l ow doses of 
GS-2829 and 
GS-6779 or 
Placll>o In HP 
Doslrg dCcl'locts 
4, S,and8 k 
dependent on &ta 
fromCohon: 3 043 
and al available 
safety&tafrom 
prior cohorts 
Cohort4*: 
High dous of 
GS-2829 and 
GS-6779 or 
Placll>o In HP 
COhorts•: 
Low doses of 
GS-2829 and 
GS-6779 or 
Placebo In 
1/trally 
suppressed 
CHB 
lheth.,doourse of 
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t. dependent on data from Cdlcrt • 
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avalable safetydata 
from al dosed cohorts 
Final 
Amendment2 
Cohort 8°: 
High dousof 
GS-2829 and 
GS-6779 0< 
Placll>o In HP 
Cohort 1°: 
High doses of 
GS-2829 and 
GS-6779 0< 
Placll>o In 
1/trally 
suppressed 
CHB 
Cohort 6": 
High doses of 
GS-2829 and 
GS-6779 0< 
Placll>o In 
1/trally 
suppressed 
CHB 
Cobor·ts 1, 2, and 3: Cohorts 1 and 2 will enroll concurrently and will receive investigational product in 2 groups, a sentinel group (2 active 
and 1 PBO, randomly assigned) and the remainder ( 6 active and 1 PBO), for a total of approximately 10 healdiy participants per cohort 
Dosing the remainder of Cohorts 1 and 2 and initiation of Cohort 3 will commence at the discretion of the investigator in consultation with die 
sponsor's medical monitor upon evaluation of available safety data through at least 14 days after the first dose of investigational product in 
Cohort 1 and 2 sentinel participants. The duration of diis review period may be increased based on emerging preliminary safety data. 
Decisions to initiate a higher dose level cohort and any required revisions to postdose monitoring will be made upon die review of all 
available safety data by die SRT 
Cobor·ts 4 and 5: Initiation of Cohorts 4 and 5, which will run concurrently, will be determined at the discretion of the SRTbasedon die 
evaluation of available safety data dirough Day 43 (14 Days after die initial dose ofboth investigational products for all participants in 
enrolled in Cohort 3), in addition to all available safety data from Cohorts 1 and 2. The decision on cohort initiation will be based on 
prespecified criteria agreed upon by the SRT and docwnented in die SRT charter. The duration of diis review period may be increased based 
on die emerging and cumulative safety data. 
Cobor·t 8: Initiation of Cohort 8 will be determined at die discretion of die SRT based on the evaluation of available safety data through Day 
43 (14 days after all participants in Cohort 3 have completed the initial dose ofbodi investigational products), in addition to all available 
safety data from prior cohorts. Initiation of a third dose of 2-vector combination, dierapy will be deteimined at the discretion of the SRT based 
on die evaluation of die available safety data dirough Day 99 (14 days after all participants in Cohort 4 have completed the second dose of 
bodi investigational products), in addition to all available safety data. The decision on cohort initiation will be based on prespecified criteria 
agreed upon by die SRT and documented in the SRT charter. Toe duration of this review period may be increased based on the emerging and 
cumulative safety data. 
Cobor·t 6: Initiation of Cohort 6 will be determined at die discretion of die SRT based on the evaluation of available safety data through Day 
43 (14 days after initial dose ofbodi the investigational products for all participants enrolled in Cohort 4), available safety data from 
participants enrolled in Cohort 5, and all available safety data from all dosed cohorts, and dosing will be initiated only in die absence of dose-
limiting toxicity and/or meeting any prespecified stopping criteria Toe duration of this review period may be increased based on die emerging 
and cumulative safety data. 
Cobor·t 7: Initiation of Cohort 7 will be determined at die discretion of die SRT based on the evaluation of available safety data through 14 
days (Day 43) after initial dose ofbodi the investigational products for all participants enrolled in Cohort 4, available safety data from 
participants enrolled in Cohort 5, and all available safety data from all dosed cohorts. Initiation of the diird dose of 2 vector combination 
dierapy will be determined at the discretion of SRT based on the evaluation of die available safety data dirough Day 99 (14 days after all 
participants in Cohort 4 have comple1led the second dose ofbodi investigational products), in addition to all available safety data. The decision 
on cohort initiation will be based on prespecified criteria agreed upon by the SRT and docwnented in die SRT charter. The duration of this 
review period may be increased based on die emerging and cumulative safety data. 
CHB = chronic hepatitis B; D = Day; HBV = hepatitis B vims; HP = healthy participant; SRT = Safety Review Team 
CONFIDENTIAL 
Page 15 
20 July 2023 

GS-2829 and GS-6779
Protocol GS-US-642-5670
Final
Gilead Sciences, Inc.
Amendment 2
CONFIDENTIAL
Page 16
20 July 2023
Figure 2.
Schema for Cohorts 1 and 2 (Two Total Doses)
HBV = hepatitis B virus; HP = healthy participant; PBMC = peripheral blood mononuclear cell
Note: A follow-up phone call will be performed on Days 2, 3, 58, and 59.
Figure 3.
Schema for Cohorts 3, 4, 5, and 6 (Four Total Doses)
Day -45
8
Phase 1a 
• Cohort 3: Low Doses of GS-2829 and GS-6779 or Placebo in HP
• Cohort 4: High Doses of GS-2829 and GS-6779 or Placebo in HP
Phase 1b
• Cohort 5: Low Doses of GS-2829 and GS-6779 or Placebo in virally 
suppressed participants with CHB
• Cohort 6: High Doses of GS-2829 and GS-6779 or Placebo in 
virally suppressed participants with CHB
15
29
57
71
85
113
141**
Baseline
1
Screening
GS-2829 dose or Placebo
GS-6779 dose or Placebo
PBMC for Biomarker Cellular Assays
Serum for HBV-Targeting Antibody Measurements
Whole Blood for Biomarker Analysis
HBV Neutralizing Antibody and Antivector Antibody Assessment
HBV Viral Biomarkers (Phase 1b only)
HBV Genomic Sequencing (Phase 1b only)
HBV Genotyping (Phase 1b only)
Day 141, Day 197 and Day 225 visits are only required for female 
participants of childbearing potential
43
92
169
99
225**
253
X
197**
**
X
X
X
X
X
X
X
X
CHB = chronic hepatitis B; HBV = hepatitis B virus; HP = healthy participant; PBMC = peripheral blood mononuclear cell
Note: A follow-up phone call will be performed on Days 2, 3, 30, 31, 58, 59, 86, and 87.
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13 
6. 

GS-2829 and GS-6779
Protocol GS-US-642-5670
Final
Gilead Sciences, Inc.
Amendment 2
CONFIDENTIAL
Page 17
20 July 2023
Figure 4.
Schema for Cohorts 7 and 8 (Six Total Doses)
Day -45
8
Phase 1a 
• Cohort 8: High Doses of GS-2829 and GS-6779 or Placebo in HP
Phase 1b
• Cohort 7: High Doses of GS-2829 and GS-6779 or Placebo in 
virally suppressed participants with CHB
15
29
57
71
85
113
141  
Baseline
1
Screening
GS-2829 dose or Placebo
GS-6779 dose or Placebo
PBMC for Biomarker Cellular Assays
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Whole Blood for Biomarker Analysis
HBV Neutralizing Antibody and Antivector Antibody Assessment
HBV Viral Biomarkers (Phase 1b only)
HBV Genomic Sequencing (Phase 1b only)
HBV Genotyping (Phase 1b only)
Day 197, Day 253, and Day 281 visits are only required for female 
participants of childbearing potential
43
169
99
225 253**
X
**
X
X
X
X
X
281** 309
127
X
X
148
X
197**
155
X
CHB = chronic hepatitis B; HBV = hepatitis B virus; HP = healthy participant; PBMC = peripheral blood mononuclear cell
Note: A follow-up phone call will be performed on Days 2, 3, 30, 31, 58, 59, 86, 87, 114, 115, 142, and 143..
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13 

GS-2829 and GS-6779
Protocol GS-US-642-5670
Final
Gilead Sciences, Inc.
Amendment 2
CONFIDENTIAL
Page 18
20 July 2023
STUDY PROCEDURES TABLES
Table 1.
Schedule of Assessments, Phase 1a – Cohorts 1 and 2 (Two Total Doses)
Study Period
Screen
Active Dosing
Safety Follow-up
Study Day
Baseline
Day 1
Day
8
Day
15
Day
29
Day
57
Day
64
Day
71
Day
85
Day
113a
Day
141
Day
169a
Day
197a
Day
225
ET
Visit Window (Days)
45 Days
N/A
± 1
± 1
± 3
± 3
± 1
± 1
± 3
± 7
± 7
± 7
± 7
± 7
N/A
Study Weeks
1
1
2
4
8
9
10
12
16
20
24
28
32
Dosing (PBO or IP)b
X
X
Written informed consent; I/E 
criteria; medical history 
X
Adverse events and 
concomitant medications 
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
General Assessments and Laboratory Assessments
Complete physical 
examinationc
X
X
X
X
X
Symptom-directed physical 
examinationd
X
X
X
X
X
X
X
HIV-1, HBV, and HCV testing 
X
Xc
Xc,e
Xe
X
Height 
X
Weight 
X
X
X
X
X
12-lead ECG
X
X
X
Vital signs 
X
Xf
X
X
X
Xf
X
X
X
X
X
X
Urinalysis 
X
Xc
X
X
Xc
X
X
X
X
X
Hematologyg 
X
Xc
X
X
Xc
X
X
X
X
X
FSHh
X
Serum pregnancy testi
X
Xc
X
Xc
X
X
X
X
X
X
X
Urine pregnancy testi 
X
X

GS-2829 and GS-6779
Protocol GS-US-642-5670
Final
Gilead Sciences, Inc.
Amendment 2
CONFIDENTIAL
Page 19
20 July 2023
Study Period
Screen
Active Dosing
Safety Follow-up
Study Day
Baseline
Day 1
Day
8
Day
15
Day
29
Day
57
Day
64
Day
71
Day
85
Day
113a
Day
141
Day
169a
Day
197a
Day
225
ET
Visit Window (Days)
45 Days
N/A
± 1
± 1
± 3
± 3
± 1
± 1
± 3
± 7
± 7
± 7
± 7
± 7
N/A
Study Weeks
1
1
2
4
8
9
10
12
16
20
24
28
32
Urine drug and alcohol screen 
X
Xc
Chemistry and liver function 
testsj
X
Xc
X
X
Xc
X
X
X
X
X
Creatinine clearancek
X
X
X
X
X
X
Coagulationl
X
Xc
X
X
Xc
X
X
X
X
X
Local and Systemic Reactogenicity
Dispense participant 
diarym
X
X
Review Participant 
diarym
X
X
X
X
Immunology and Biomarkers
PBMC collection for 
biomarker cellular assays
Xc
X
X
X
Xc
X
X
X
X
X
X
Serum collection for 
HBV-targeting antibody 
measurements
Xc
X
Xc
X
X
X
X
Whole blood collection for 
biomarker analysis
Xc
X
Xc
X
X
Clinical Virology
Serum collection for HBV 
neutralizing antibody and 
antivector antibody assessment
Xc
X
X
Xc
X
X
X
X
ECG = electrocardiogram; ET = early termination; FSH = follicle-stimulating hormone; HBV = hepatitis B virus; HCV = hepatitis C virus; HIV-1 = human immunodeficiency 
virus type 1; I/E = inclusion/exclusion; IP = investigational product; N/A = not applicable; PBMC = peripheral blood mononuclear cell; PBO = placebo; Screen = screening
I 
I 
I I I I I I I I I I I I I 
I 
I 
I I I I I I I I I I I I I 

GS-2829 and GS-6779
Protocol GS-US-642-5670
Final
Gilead Sciences, Inc.
Amendment 2
CONFIDENTIAL
Page 20
20 July 2023
a
These visits are only required for pregnancy testing for women of childbearing potential. Participants who are able to access an at-home urine pregnancy test from the clinical 
site may conduct their pregnancy test at home and will be contacted by site staff to confirm the result. If urine pregnancy results are equivocal or positive, a serum pregnancy 
test will be required.
b
Participant shall receive the appropriate investigational product or PBO, as detailed in Section 5.3 and Table 8. Sentinel participants will be observed at the study site for at 
least 8 hours after investigational product administration on Day 1, and for at least 4 hours following each administration of investigational product for all subsequent doses. 
All other Phase 1a participants will be monitored in the clinic for at least 4 hours following each dose of investigational product. Participants will receive a follow-up phone 
call for 2 consecutive days following each dose to review protocol restrictions, adverse events, any concomitant medication usage, and completion of participant diaries.
c
Collection of vital signs, physical examination, and blood/urine samples should be completed prior to investigational product administration.
d
Symptom-driven physical examinations shall be performed as deemed necessary.
e
At the discretion of the investigator. 
f
Indicated assessment shall be performed prior to dosing and within 15 to 30 minutes following investigational product administration.
g
Hematology assessments are listed in Section 6.4.5.
h
An FSH test is required for participants assigned female at birth who are younger than 54 years, not on hormonal contraception, and who have stopped menstruating for at 
least 12 months but do not have documentation of ovarian hormonal failure.
i
For participants assigned female at birth and of childbearing potential. On days of investigational product administration, urine pregnancy testing is also required to determine 
pregnancy status prior to dosing.
j
Chemistry and liver function assessments are listed in Section 6.4.5.
k
Central laboratory will calculate creatinine clearance.
l
Coagulation assessments are listed in Section 6.4.5. 
m
Participants will be asked to record potential vaccine reactions based on solicited events via diary for 7 days following each administration of investigational product. Review 
of participant reactogenicity data will occur at each visit after vaccination up to 7 days postdose or beyond for cases with ongoing events after 7 days postdose.

GS-2829 and GS-6779
Protocol GS-US-642-5670
Final
Gilead Sciences, Inc.
Amendment 2
CONFIDENTIAL
Page 21
20 July 2023
Table 2.
Schedule of Assessments, Phase 1a – Cohorts 3, 4 and Phase 1b - Cohorts 5 and 6 (Four Total Doses)
Study Period
Screen
Active Dosing
Safety Follow-up
Study Day 
Baseline 
Day 1
Day
8
Day
15
Day
29
Day
43
Day
57
Day
71
Day
85
Day
92
Day
99
Day
113
Day
141a
Day
169
Day
197a
Day
225a
Day
253
ET
Visit Window (Days) 
45 
Days
N/A
± 1
± 1
± 3
± 1
± 3
± 1
± 3
± 1
± 1
± 3
± 7
± 7
± 7
± 7
± 7
N/A
Study Weeks
1
1
2
4
6
8
10
12
13
14
16
20
24
28
32
36
Dosing (PBO or IP)b
X
X
X
X
Written informed 
consent; I/E criteria; 
medical history 
X
Adverse events and 
concomitant 
medications 
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
General Assessments and Laboratory Assessments 
Complete physical 
examinationc
X
X
X
X
X
X
X
Symptom-directed 
physical examinationd
X
X
X
X
X
X
X
X
HIV-1 testing 
X
Xe
X
HBV testingp
X
Xc
Xc,e
Xe
X
HCV testing
X
Xe
X
HDV testingl
X
Height 
X
Weight 
X
X
X
X
X
X
X
12-lead ECG 
X
X
X
X
Vital signs 
X
Xf
X
Xf
X
Xf
X
Xf
X
X
X
X
X
X
Urinalysis 
X
Xc
Xc
Xc
X
Xc
X
X
X
X
X
Hematologyg 
X
Xc
X
Xc
X
Xc
X
Xc
X
X
X
X
X
FSHh
X
Serum pregnancy testi
X
Xc
Xc
Xc
Xc
X
X
X
X
X
X
X

GS-2829 and GS-6779
Protocol GS-US-642-5670
Final
Gilead Sciences, Inc.
Amendment 2
CONFIDENTIAL
Page 22
20 July 2023
Study Period
Screen
Active Dosing
Safety Follow-up
Study Day 
Baseline 
Day 1
Day
8
Day
15
Day
29
Day
43
Day
57
Day
71
Day
85
Day
92
Day
99
Day
113
Day
141a
Day
169
Day
197a
Day
225a
Day
253
ET
Visit Window (Days) 
45 
Days
N/A
± 1
± 1
± 3
± 1
± 3
± 1
± 3
± 1
± 1
± 3
± 7
± 7
± 7
± 7
± 7
N/A
Study Weeks
1
1
2
4
6
8
10
12
13
14
16
20
24
28
32
36
Urine pregnancy testi
Xc
Xc
Xc
Xc
Urine drug and alcohol 
screen 
X
X
Chemistry and liver 
function testsj 
X
Xc
X
Xc
X
Xc
X
Xc
X
X
X
X
X
Creatinine clearancek
X
X
X
X
X
X
X
Autoantibody testl
X
FibroScan for 
participants with none 
in past 6 monthsl 
X
Coagulationm
X
Xc
X
Xc
X
Xc
X
Xc
X
X
X
X
X
Local and Systemic Reactogenicity 
Dispense participant 
diaryn
X
X
X
X
Review participant 
diaryn
X
X
X
X
X
X
Immunology and Biomarkers 
PBMC collection for 
biomarker cellular 
assays
Xc
X
X
Xc
X
Xc
X
Xc
X
X
X
X
X
Serum collection for 
HBV-targeting antibody 
measurements 
Xc
Xc
Xc
Xc
X
X
X
Whole blood collection 
for biomarker analysis 
Xc
X
Xc
X
Xc
X
Xc
X
X
I I 
I I I I I I I I I I I I I I I I 

GS-2829 and GS-6779
Protocol GS-US-642-5670
Final
Gilead Sciences, Inc.
Amendment 2
CONFIDENTIAL
Page 23
20 July 2023
Study Period
Screen
Active Dosing
Safety Follow-up
Study Day 
Baseline 
Day 1
Day
8
Day
15
Day
29
Day
43
Day
57
Day
71
Day
85
Day
92
Day
99
Day
113
Day
141a
Day
169
Day
197a
Day
225a
Day
253
ET
Visit Window (Days) 
45 
Days
N/A
± 1
± 1
± 3
± 1
± 3
± 1
± 3
± 1
± 1
± 3
± 7
± 7
± 7
± 7
± 7
N/A
Study Weeks
1
1
2
4
6
8
10
12
13
14
16
20
24
28
32
36
Clinical Virology 
HBV neutralizing 
antibody and antivector 
antibody assessment
Xc
X
Xc
Xc
Xc
X
X
X
X
HBV viral biomarkerso,l
Xc
X
Xc
Xc
Xc
X
X
X
X
HBV genomic 
sequencingl
Xc
Xc
Xc
Xc
X
X
X
X
HBV genotypingl
X
Xc
DNA = deoxyribonucleic acid; ECG = electrocardiogram; ET = early termination; FSH = follicle-stimulating hormone; HBcrAg = hepatitis B core-related antigen; 
HBeAg = hepatitis B e antigen; HBsAg = hepatitis B surface antigen; HBV = hepatitis B virus; HCV = hepatitis C virus; HDV = hepatitis D virus; HIV-1 = human 
immunodeficiency virus type 1; I/E = inclusion/exclusion; IP = investigational product; N/A = not applicable; PBMC = peripheral blood mononuclear cell; PBO = placebo; 
RNA = ribonucleic acid; Screen = screening
a
These visits are only required for pregnancy testing for women of childbearing potential. Participants who are able to access an at-home urine pregnancy test from the clinical 
site may conduct their pregnancy test at home and will be contacted by site staff to confirm the result. If urine pregnancy results are equivocal or positive, a serum pregnancy 
test will be required.
b
Participant shall receive the appropriate investigational product or PBO, as detailed in Section 5.3 and Table 8. Participants in Cohorts 3 and 4 will be monitored in the clinic 
for at least 4 hours following each dose of investigational product. Participants in Cohorts 5 and 6 will be monitored in the clinic for at least 2 hours following each dose of 
investigational product. Participants may be required to remain in the clinic for additional observation at the discretion of the investigator. Participants will receive a follow-up 
phone call for 2 consecutive days following each dose to review protocol restrictions, adverse events, any concomitant medication usage, and completion of participant 
diaries.
c
Collection of vital signs, physical examinations, and blood/urine samples should be completed prior to investigational product administration.
d
Symptom-driven physical examinations shall be performed as deemed necessary.
e
At the discretion of the investigator.
f
Indicated assessment shall be taken prior to dosing and within 15 to 30 minutes following investigational product administration.
g
Hematology assessments are listed in Section 6.4.5.
h
An FSH test is required for participants assigned female at birth who are younger than 54 years, not on hormonal contraception, and who have stopped menstruating for at 
least 12 months but do not have documentation of ovarian hormonal failure.
i
For participants assigned female at birth and of childbearing potential. On days of investigational product administration, urine pregnancy testing is also required to determine 
pregnancy status prior to dosing.
j
Chemistry and liver function assessments are listed in Section 6.4.5.
k
Central laboratory will calculate creatinine clearance. 
l
Required for Phase 1b only.

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m
Coagulation assessments are listed in Section 6.4.5.
n
Participants will be asked to record potential vaccine reactions based on solicited events via diary for 7 days following each administration of investigational product. Review 
of participant reactogenicity data will occur at each visit after vaccination up to 7 days postdose or beyond for cases with ongoing events after 7 days postdose. 
o
To include the assessments of: HBV DNA, quantitative HBsAg, anti-HBsAg antibody, HBcrAg, HBeAg, HBV RNA.
p
Phase 1a: HBV testing is for HBsAg with reflex to HBV DNA, and hepatitis B core antibody. Phase 1b: HBV testing is for HBsAg, hepatitis B core antibody, HBV DNA, 
and quantitative HBsAg. 

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Table 3.
Schedule of Assessments, Phase 1a – Cohort 8 and Phase 1b - Cohort 7 (Six Total Doses)
Study Period
Screen
Active Dosing
Safety Follow-up
Study Day 
Base-
line 
Day 1
Day
8
Day
15
Day
29
Day
43
Day
57
Day
71
Day
85
Day
99
Day
113
Day
127
Day
141
Day
148
Day 
155
Day
169
Day
197a
Day
225
Day
253 a
Day
281 a
Day
309
ET
Visit Window 
(Days) 
45 
Days
N/A
± 1
± 1
± 3
± 1
± 3
± 1
± 3
± 1
± 3
± 3
± 3
± 3
± 7
± 7
± 7
± 7
± 7
± 7
± 7
N/A
Study Weeks
1
1
2
4
6
8
10
12
14
16
18
20
21
22
24
28
32
36
40
44
Dosing (PBO 
or IP)b
X
X
X
X
X
X
Written 
informed 
consent; I/E 
criteria; 
medical 
history 
X
Adverse 
events and 
concomitant 
medications 
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
General Assessments and Laboratory Assessments 
Complete 
physical 
examinationc
X
X
X
X
X
X
X
X
X
Symptom-
directed 
physical 
examinationd
X
X
X
X
X
X
X
X
X
X
HIV-1 testing 
X
Xe
X
HBV testing p
X
Xc
Xc,e
Xe
X
HCV testing
X
Xe
X
HDV testingl
X
Height 
X
Weight 
X
X
X
X
X
X
X
X
X
12-lead ECG 
X
X
X
X
X

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Study Period
Screen
Active Dosing
Safety Follow-up
Study Day 
Base-
line 
Day 1
Day
8
Day
15
Day
29
Day
43
Day
57
Day
71
Day
85
Day
99
Day
113
Day
127
Day
141
Day
148
Day 
155
Day
169
Day
197a
Day
225
Day
253 a
Day
281 a
Day
309
ET
Visit Window 
(Days) 
45 
Days
N/A
± 1
± 1
± 3
± 1
± 3
± 1
± 3
± 1
± 3
± 3
± 3
± 3
± 7
± 7
± 7
± 7
± 7
± 7
± 7
N/A
Study Weeks
1
1
2
4
6
8
10
12
14
16
18
20
21
22
24
28
32
36
40
44
Vital signs 
X
Xf
X
Xf
X
Xf
X
Xf
X
Xf
X
Xf
X
X
X
X
X
X
Urinalysis 
X
Xc
Xc
Xc
X
Xc
X
Xc
X
Xc
X
X
X
X
X
Hematologyg 
X
Xc
X
Xc
X
Xc
X
Xc
X
Xc
X
Xc
X
X
X
X
X
FSHh
X
Serum 
pregnancy testi
X
Xc
Xc
Xc
Xc
Xc
Xc
X
X
X
X
X
X
X
Urine 
pregnancy
testi
Xc
Xc
Xc
Xc
Xc
Xc
Urine drug 
and alcohol 
screen 
X
X
Chemistry and 
liver function 
testsj 
X
Xc
X
Xc
X
Xc
X
Xc
X
Xc
X
Xc
X
X
X
X
X
Creatinine 
clearancek
X
X
X
X
X
X
X
X
X
X
Autoantibody 
testl
X
FibroScan for 
participants 
with none in 
past 6 monthsl 
X
Coagulationm
X
Xc
X
Xc
X
Xc
X
Xc
X
Xc
X
Xc
X
X
X
X
X
Local and Systemic Reactogenicity 
Dispense 
participant 
diaryn
X
X
X
X
X
X
I I I I I I I I I I I I I I I I I I I I I I 

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Study Period
Screen
Active Dosing
Safety Follow-up
Study Day 
Base-
line 
Day 1
Day
8
Day
15
Day
29
Day
43
Day
57
Day
71
Day
85
Day
99
Day
113
Day
127
Day
141
Day
148
Day 
155
Day
169
Day
197a
Day
225
Day
253 a
Day
281 a
Day
309
ET
Visit Window 
(Days) 
45 
Days
N/A
± 1
± 1
± 3
± 1
± 3
± 1
± 3
± 1
± 3
± 3
± 3
± 3
± 7
± 7
± 7
± 7
± 7
± 7
± 7
N/A
Study Weeks
1
1
2
4
6
8
10
12
14
16
18
20
21
22
24
28
32
36
40
44
Review 
participant 
diaryn
X
X
X
X
X
X
X
Immunology and Biomarkers 
PBMC 
collection for 
biomarker 
cellular assays
Xc
X
Xc
X
Xc
X
Xc
X
Xc
X
X
X
X
X
Serum 
collection for 
HBV-
targeting 
antibody 
measurements 
Xc
Xc
Xc
Xc
Xc
Xc
X
X
X
Whole blood 
collection for 
biomarker 
analysis 
Xc
Xc
X
Xc
X
Xc
X
Xc
X
X
Clinical Virology
HBV 
neutralizing 
antibody and 
antivector 
antibody 
assessment
Xc
X
Xc
Xc
Xc
Xc
Xc
X
X
X
X
HBV viral 
biomarkerso,l
Xc
X
Xc
Xc
Xc
Xc
Xc
X
X
X
X
HBV genomic 
sequencingl
Xc
Xc
Xc
Xc
Xc
Xc
X
X
X
X
HBV 
genotypingl
X
Xc

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Amendment 2
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DNA = deoxyribonucleic acid; ECG = electrocardiogram; ET = early termination; FSH = follicle-stimulating hormone; HBcrAg = hepatitis B core-related antigen; 
HBeAg = hepatitis B e antigen; HBsAg = hepatitis B surface antigen; HBV = hepatitis B virus; HCV = hepatitis C virus; HDV = hepatitis D virus; HIV-1 = human 
immunodeficiency virus type 1; I/E = inclusion/exclusion; IP = investigational product; N/A = not applicable; PBMC = peripheral blood mononuclear cell; PBO = placebo; RNA = 
ribonucleic acid; Screen = screening
a
These visits are only required for pregnancy testing for women of childbearing potential. Participants who are able to access an at-home urine pregnancy test from the clinical 
site may conduct their pregnancy test at home and will be contacted by site staff to confirm the result. If urine pregnancy results are equivocal or positive, a serum pregnancy 
test will be required.
b
Participant shall receive the appropriate investigational product or PBO, as detailed in Section 5.3 and Table 8. Participants in Cohort 7 will be monitored in the clinic for at 
least 2 hours following each dose of investigational product. Participants may be required to remain in the clinic for additional observation at the discretion of the investigator. 
Participants will receive a follow-up phone call for 2 consecutive days following each dose to review protocol restrictions, adverse events, any concomitant medication usage, 
and completion of participant diaries.
c
Collection of vital signs, physical examinations, and blood/urine samples should be completed prior to investigational product administration.
d
Symptom-driven physical examinations shall be performed as deemed necessary.
e
At the discretion of the investigator.
f
Indicated assessment shall be taken prior to dosing and within 15 to 30 minutes following investigational product administration.
g
Hematology assessments are listed in Section 6.4.5.
h
An FSH test is required for participants assigned female at birth who are younger than 54 years, not on hormonal contraception, and who have stopped menstruating for at 
least 12 months but do not have documentation of ovarian hormonal failure.
i
For participants assigned female at birth and of childbearing potential. On days of investigational product administration, urine pregnancy testing is also required to determine 
pregnancy status prior to dosing.
j
Chemistry and liver function assessments are listed in Section 6.4.5.
k
Central laboratory will calculate creatinine clearance. 
l
Required for Phase 1b only.
m
Coagulation assessments are listed in Section 6.4.5.
n
Participants will be asked to record potential vaccine reactions based on solicited events via diary for 7 days following each administration of investigational product. Review 
of participant reactogenicity data will occur at each visit after vaccination up to 7 days postdose or beyond for cases with ongoing events after 7 days postdose. 
o
To include the assessments of: HBV DNA, quantitative HBsAg, anti-HBsAg antibody, HBcrAg, HBeAg, HBV RNA.
p
HBV testing is for HBV surface antigen and antibody.

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Amendment 2
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Table 4, Table 5, and Table 6 are for biomarker collections only.
Table 4.
Sampling for Biomarker Assessments for Phase 1a – Cohorts 1 and 2 (Two Total Doses)
Active Dosing
Safety Follow-up
Sample Type
Day 
1
Day 
8
Day 
15
Day 
29
Day 
57
Day 
64
Day 
71
Day 
85
Day 141
Day 225
ET
Visit Window 
(Days)
N/A
± 1
± 1
± 3
± 3
± 1
± 1
± 3
± 7
± 7
N/A
Study Weeks
Biomarker Assay
1
1
2
4
8
9
10
12
20
32
PBMC
HBV-specific 
IFN-γ T-cell 
ELISpot
X
X
X
X
X
X
X
X
X
PBMC
T-cell ICS
X
X
X
X
X
X
X
PBMC
HBV-specific 
B-cells
X
X
X
X
X
PBMC
CyTOF
X
X
X
X
X
PBMC
Single cell 
multiomics
X
X
X
X
X
PBMC
TCR repertoire
X
X
X
X
X
Serum
HBV-specific 
antibodies
X
X
X
X
X
X
X
Serum
Immune 
complexes
X
X
X
X
X
X
X
Plasma
Cytokine analysis
X
X
X
X
X
Whole blood
Bulk gene 
expression
X
X
X
X
X
CyTOF = cytometry by time of flight; ELISpot = enzyme-linked immunospot assay; ET = early termination; HBV = hepatitis B virus; ICS = intracellular cytokine staining; 
IFN-γ = interferon gamma; N/A = not applicable; PBMC = peripheral blood mononuclear cell; TCR = T-cell receptor

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Table 5.
Sampling for Biomarker Assessments for Phase 1a – Cohorts 3 and 4 and Phase 1b - Cohorts 5 and 6 
(Four Total Doses)
Active Dosing
Safety Follow-up
Sample Type
Day 
1
Day
8
Day
15
Day
29
Day
43
Day
57
Day
71
Day
85
Day
92
Day
99
Day
113
Day
169
ET
Visit Window 
(Days)
N/A
± 1
± 1
± 3
± 1
± 3
± 1
± 3
± 1
± 1
± 3
± 7
N/A
Study Weeks
Biomarker 
Assay
1
1
2
4
6
8
10
12
13
14
16
24
PBMC
HBV-specific 
IFN-γ T-cell 
ELISpot
X
X
X
X
X
X
X
X
X
X
X
PBMC
T-cell ICS
X
X
X
X
X
X
X
X
X
X
PBMC
HBV-specific 
B-cells
X
X
X
X
X
PBMC
CyTOF
X
X
X
X
X
X
PBMC
Single cell 
multiomics
X
X
X
X
X
X
X
X
X
X
PBMC
TCR 
repertoire
X
X
X
X
X
X
X
Serum
HBV-specific 
antibodies
X
X
X
X
X
X
X
Serum
Immune 
complexes
X
X
X
X
X
X
X
Plasma
Cytokine 
analysis
X
X
X
X
X
X
X
X
X
Whole blood
Bulk gene 
expression
X
X
X
X
X
X
X
X
X
CyTOF = cytometry by time of flight; ELISpot = enzyme-linked immunospot assay; ET = early termination; HBV = hepatitis B virus; ICS = intracellular cytokine staining; 
IFN-γ = interferon gamma; N/A = not applicable; PBMC = peripheral blood mononuclear cell; TCR = T-cell receptor

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Table 6.
Sampling for Biomarker Assessments for Phase 1a – Cohort 8 and Phase 1b - Cohort 7 (Six Total Doses)
Active Dosing
Safety Follow-up
Sample 
Type
Day 
1
Day
8
Day
29
Day
57
Day
71
Day
85
Day
99
Day
113
Day
127
Day
141
Day
148
Day
155
Day
169
Day
225
ET
Visit 
Window 
(Days)
N/A
± 1
± 3
± 3
± 1
± 3
± 1
± 3
± 3
± 3
± 3
± 3
± 7
± 7
N/A
Study 
Weeks
Biomarker 
Assay
1
1
4
8
10
12
14
16
18
20
21
22
24
32
PBMC
HBV-specific 
IFN-γ T-cell 
ELISpot
X
X
X
X
X
X
X
X
X
X
X
X
PBMC
T-cell ICS
X
X
X
X
X
X
X
X
X
X
X
PBMC
HBV-specific 
B-cells
X
X
X
X
X
X
X
PBMC
CyTOF
X
X
X
X
X
X
PBMC
Single cell 
multiomics
X
X
X
X
X
X
X
X
X
X
X
PBMC
TCR 
repertoire
X
X
X
X
X
X
X
Serum
HBV-specific 
antibodies
X
X
X
X
X
X
X
X
X
Serum
Immune 
complexes
X
X
X
X
X
X
X
X
X
Plasma
Cytokine 
analysis
X
X
X
X
X
X
X
X
X
X
Whole 
blood
Bulk gene 
expression
X
X
X
X
X
X
X
X
X
X
CyTOF = cytometry by time of flight; ELISpot = enzyme-linked immunospot assay; ET = early termination; HBV = hepatitis B virus; ICS = intracellular cytokine staining; 
IFN-γ = interferon gamma; N/A = not applicable; PBMC = peripheral blood mononuclear cell; TCR = T-cell receptor

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1.
INTRODUCTION
1.1.
Background
Chronic hepatitis B (CHB) is the most prevalent viral hepatitis disease, globally affecting close 
to 296 million individuals {World Health Organization (WHO) 2021}. Most people living with 
CHB are in the Western Pacific Region and Sub-Saharan Africa, where 116 and 82 million 
people, respectively, are chronically infected. The International Agency for Research on Cancer 
estimates that, globally, 1 in 3 of all cases of hepatocellular carcinoma (HCC) are secondary to 
CHB. In Africa and East Asia, the proportion is closer to 60% {Singal 2020}. There are currently 
several prophylactic hepatitis B virus (HBV) vaccines commercially available with efficacies 
approaching 95% in some populations. Coverage has improved significantly since 2019 but is 
not optimal {Pattyn 2021} as there is still a high rate of new cases of HBV annually in many 
regions of the world. Chronic infection with HBV has multiple clinical sequelae such as chronic 
liver disease that progresses to cirrhosis, and end-stage liver disease (ESLD) in approximately 
7% of cases even with nucleos(t)ide analogues (NAs) therapy {Liaw 2004}.
Currently, 2 classes of drugs have been approved for treatment of CHB, NAs, and interferons 
(IFNs). Nucleos(t)ide analogues are very effective at suppressing viral replication and reducing 
the risk of complications of CHB, but for those who meet current treatment criteria, lifelong 
therapy is required. Additionally, concerns of adherence, cost, and potential HBV reactivation 
secondary to treatment interruptions have limited use of NAs to only a subset of patients with 
CHB. Pegylated IFN-based therapies have achieved modest levels of HBV DNA suppression 
and hepatitis B surface antigen (HBsAg) loss in the range of 3% to 3.5%, ie, functional cure 
(defined as HBV DNA suppression, HBsAg loss with or without anti-HBsAg seroconversion) 
{Ren 2019}. This treatment unfortunately is poorly tolerated. Combinations of NAs and IFNs 
have been evaluated in prior studies attempting to achieve HBV functional cure but HBsAg loss 
has been achieved in only up to 9% of patients {Ren 2019}. 
Immune correlates of functional cure in individuals with resolved acute HBV and CHB on NA 
therapy show that cure is associated with increases in HBV-specific CD4+ and CD8+ T-cells 
{Boni 2012, Hoogeveen 2022, Hoogeveen 2019, Maini 2018}. Consistent with the clinical 
observations, studies in CD8-depleted nonhuman primates suggest that HBV-specific CD8+ 
T-cells are critical for eliminating existing HBV-infected hepatocytes {Thimme 2003}. 
Furthermore, numerous studies show that HBV-specific CD8+ T-cell responses are associated 
with improved viral control and functional cure {Chen 2020, de Niet 2016, Fisicaro 2010, Pallett 
2017}. Therefore, therapeutic strategies, such as vaccination, will need to induce a strong 
CD8+ T-cell response to maximize the likelihood of achieving a functional cure {Boni 2012, 
Chen 2020, de Niet 2016, Fisicaro 2010, Hoogeveen 2019, Maini 2018, Pallett 2017}. Induction 
of anti-HBsAg antibody responses is also highly desirable for patients with CHB, as viral 
rebound is less likely to occur after HBsAg loss in patients who also achieve anti-HBsAg 
seroconversion {Yip 2018}. 

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Different combinations of investigational products are currently in clinical testing for their ability 
to induce HBV functional cure {Roca Suarez 2021}. Functional cure is expected to significantly 
reduce risk of progression to ESLD and HCC. These treatment concepts usually include 3 main 
components: (1) viral antigen reduction strategies, (2) immune system modulation with the aim 
of reversing T-cell exhaustion, and (3) stimulation of an HBV-specific immune response targeted 
at viral elimination. Therapeutic vaccines are considered a key component of such treatment 
strategies {Cargill 2021}. In this effort, therapeutic vaccines are used to stimulate an individual’s 
immune system by stimulating HBV-specific responses against infected hepatocytes. 
Consequently, current efforts to develop HBV therapeutic vaccines seek to induce a 
polyfunctional response through the activation of HBV-specific T-cell responses and the 
induction of cross-reactive antibodies against different genotypes of HBV circulating globally. In 
a recent Phase 1b/2a study, the heterologous vector-based investigational therapeutic vaccine 
VTP-300 comprising chimpanzee adenoviral vector (ChAdOx1-HBV) and modified vaccinia 
Ankara boost HBV (MVA-HBV) induced a sustained decline in HBsAg levels both as 
monotherapy and combined with nivolumab with no vaccine-related serious adverse events 
(SAEs). One individual being treated with vaccine combined with nivolumab achieved HBsAg 
loss {Evans 2022}.
The investigational therapeutic vaccine proposed for this study is based on a nonreplicating 
arenavirus vector encoding 3 highly conserved HBV proteins: the HBV core, HBsAg, and a 
truncated inactive version of the HBV polymerase. A prior Phase 1 clinical study investigating a 
cytomegalovirus (CMV) vaccine based on a similar platform revealed that vaccinated individuals 
mounted both CD8+ and CD4+ T-cell responses that were specific for vaccine vector-encoded 
CMV glycoprotein B and phosphoprotein 65 {Schwendinger 2022}. These arenavirus vector 
vaccines use the platform used in the CMV vaccine, which has a safety profile similar to the 
current standard of care vaccines {Schwendinger 2022}. As detailed in Section 1.2.1.2 and the 
investigator's brochure (IB), GS-2829 and GS-6779 induce potent HBV-specific T-cell and 
anti-HBsAg responses and have the potential to promote functional cure, either as monotherapy 
in select patients or in combination with other agents.
1.2.
Background on Investigational Product
The investigational product is a vaccine developed on a nonreplicating arenavirus vector 
platform. A CMV vaccine developed on a similar arenavirus vector platform has been shown to 
induce indication-specific dose-dependent immune responses {Schwendinger 2022}. The 
proposed product is delivered sequentially as an alternating 2-vector therapy using different 
arenavirus viral vectors (GS-2829 and GS-6779) and will be compared with an inactive placebo 
(PBO).
A list of study interventions and their authorization status is provided in Appendix 11.2.

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1.2.1.
GS-2829 and GS-6779
1.2.1.1.
General Information
GS-2829 is an HBV-specific immunotherapy consisting of 2 coformulated nonreplicating 
arenavirus vectors derived from Pichinde virus (PICV). GS-1164202 encodes the HBV core and 
HBsAg proteins separated by a translational skip site {Liu 2017}, while GS-1164203 encodes a 
truncated and inactive version of the HBV polymerase. GS-2829 is also referred to as a 
“therapeutic vaccine” because it is intended to utilize the patient’s own immune system to induce 
a strong CD8+ T-cell response against HBV, along with HBV-specific CD4+ T-cells and 
anti-HBsAg antibodies. 
GS-2829 vectors were generated by replacing the glycoprotein gene of a wild-type arenavirus 
with an HBV antigen of interest, leaving the RNA replication and protein expression machinery 
intact while preventing the production of any new virions. These vectors are capable of entering 
cells, expressing the encoded HBV proteins, and eliciting an HBV-specific immune response, 
but are incapable of forming new infectious particles. Consequently, GS-2829 vectors are 
described as “nonreplicating” vectors. 
GS-6779 is an HBV-specific immunotherapy consisting of 2 coformulated nonreplicating 
arenavirus vectors derived from lymphocytic choriomeningitis virus (LCMV). GS-1069374 
encodes the HBV core and HBsAg proteins separated by a translational skip site {Liu 2017} 
while GS-1069370 encodes a truncated and inactive version of the HBV polymerase. GS-6779 is 
also referred to as a “therapeutic vaccine” because it is intended to utilize the patient’s own 
immune system to induce a strong CD8+ T-cell response against HBV, along with HBV-specific 
CD4+ T-cells and anti-HBsAg antibody. 
GS-6779 vectors were generated by replacing the glycoprotein gene of a wild-type arenavirus 
with an HBV antigen of interest, leaving the RNA replication and protein expression machinery 
intact while preventing the production of any new virions. GS-6779 vectors are capable of 
entering cells, expressing the encoded HBV proteins, and eliciting an HBV-specific immune 
response, but are incapable of forming new infectious particles. Consequently, GS-6779 vectors 
are described as “nonreplicating” vectors.
Immunizations of nonhuman primates with GS-2829 and GS-6779 in an alternating, sequential 
manner led to consistent, high-magnitude, HBV-specific CD8+ T-cell responses against all 
3 encoded HBV antigens, and further induced high titers of anti-HBsAg antibody. As strong 
CD8+ T-cell responses and anti-HBsAg antibodies are associated with immune clearance and 
long-term control of CHB {Boni 2012, Hoogeveen 2022, Yip 2018}, therapeutic vaccination 
with GS-2829 and GS-6779 may mediate functional cure in patients with CHB. For further 
information on GS-2829 and GS-6779, refer to the IB, including information on the following:
•
Nonclinical pharmacology and toxicology

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1.2.1.2.
Nonclinical Pharmacology and Toxicology
GS-2829 and GS-6779 have been evaluated for pharmacodynamic effect (immunogenicity) in 
nonhuman primates and have been shown to induce robust and consistent T-cell and antibody 
responses to HBV antigens. The number and schedule of GS-2829 and GS-6779 doses were 
optimized in cynomolgus macaque studies. Nonclinical toxicology was evaluated in a 
repeated-dose Good Laboratory Practice (GLP)-compliant toxicity and local tolerability study in 
cynomolgus macaques and alternating 2-vector therapy with GS-2829 and GS-6779 was well 
tolerated at 2.65  107 focus-forming unit (FFU)/dose GS-2829 and 1.59  107 FFU/dose 
GS-6779. Nonadverse findings were limited to transient increased body temperature and very 
slight edema and/or slight erythema and minimal to moderate mixed cell infiltration at the 
injection sites. These are typical vaccine-related effects.
The biodistribution and persistence of replication-deficient LCMV (rLCMV)-based vector (ie, 
the vector used in GS-6779) was evaluated in C57BL/6 mice following a single intramuscular 
injection. Quantifiable rLCMV vector genome was detected starting at 1-hour postdose (first 
sampling time point) and was below the quantifiable level in blood and tissues by Day 28, except 
the injection sites for males that remained quantifiable on Day 56, demonstrating clearance from 
blood and tissues. 
The biodistribution of the PICV-based vector (ie, the vector used in GS-2829) is being evaluated 
in an ongoing study in Wistar Han rats following a single intramuscular injection. Similar to the 
LCMV vector used in GS-6779, the PICV-based vector is also a nonreplicating arenavirus-based 
vector that is expected to be cleared from injection site, blood, and tissues and would not raise 
any nonclinical safety concern.
Further overviews of the nonclinical pharmacology and toxicology for GS-2829 and GS-6779 
are provided in the IB.
1.2.2.
Information About Comparator (Placebo)
The comparator will be an inactive PBO comprising a solution of human serum albumin with 
visual characteristics similar to GS-2829 and GS-6779.
1.2.3.
Information About Auxiliary Medicinal Products 
Treatment cohorts are described in Section 3.1. There will be no auxiliary medicinal products 
(AxMPs) used for participants in Cohorts 1 through 4 and in Cohort 8.
Auxiliary medicinal products will only be used in Cohorts 5 through 7, as participants in these 
cohorts are required to continue to receive NA therapy for HBV. Although prior studies have 
shown improvement in HBV-specific immune response after NA therapy {Stoop 2007}, the rate 
of HBsAg loss remains very low (approximately 0.5% to 1.0% per year in CHB) {Liaw 1991} 
{Chu 2007}. In this study, NA therapy is considered to be background treatment, thus, is an 
AxMP. Commercially available HBV NA therapy (ie, tenofovir and entecavir-based therapies), 
either as single agents or in combination will be appropriate in Cohort 5 through Cohort 7. 
These HBV active NAs have been used extensively in the treatment of HBV globally, have a 
well characterized safety profile, and have been shown to be well tolerated. 

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1.3.
Rationale for This Study
Current standard of care for HBV treatment, though effective at reducing progression to 
advanced liver disease and HCC, requires lifelong therapy. The nonreplicating arenavirus vectors 
GS-2829 and GS-6779 given as an alternating 2-vector therapy have shown broad polyfunctional 
HBV-specific T-cell and antibody response in nonclinical studies (Section 1.2.1.1). These results 
suggest that GS-2829 and GS-6779 may induce HBsAg loss and HBsAg seroconversion as 
monotherapy or combined with other agents. 
This study will evaluate the safety of these products in both healthy participants and 
subsequently in virally suppressed individuals with CHB. The study will be a randomized 
blinded clinical study evaluating the safety, tolerability, and immunogenicity of GS-2829 and/or 
GS-6779 compared with PBO. Participants will be randomized in a 4:1 ratio of active to PBO to 
ensure a clear comparison. 
The primary goal is to establish the safety and tolerability profile of alternating 2-vector therapy 
of GS-2829 and GS-6779 in healthy participants (Phase 1a) and virally suppressed participants 
with CHB (Phase 1b). This will be evaluated in a stepwise manner in the Phase 1a based on the 
following in healthy participants: 
•
Individual vector monotherapy (Cohorts 1 and 2), administered once every 8 weeks 
•
Alternating 2-vector combination therapy (GS-2829, followed by GS-6779), administered 
once every 4 weeks at the low-dose (Cohort 3) and high-dose levels (Cohort 4)
•
Extension of the high-dose level alternating 2-vector combination therapy with an additional 
administration of each investigational product (Cohort 8)
Study drug administration is further detailed in Section 3.2, Table 8. 
Phase 1b will evaluate the safety and tolerability profile of the alternating 2-vector therapy with 
GS-2829 and GS-6779 in virally suppressed CHB patients as follows:
•
Alternating 2-vector combination therapy, administered once every 4 weeks at the low-dose 
(Cohort 5) and high-dose (Cohort 6) levels 
•
Extension of the high-dose level alternating 2-vector combination therapy to include an 
additional administration of each investigational product (Cohort 7)
Study drug administration is further detailed in Section 3.2, Table 8.
Dose level, and the number of doses of 2-vector combination therapy has the potential to 
augment the vaccine-elicited immune response. It is critical to optimize the magnitude and 
durability of the HBV-specific immune response, believed to be a fundamental component of 
achieving an HBV cure, that is generated by the vaccine. Secondary to establishing the safety 
and tolerability profile, the magnitude and durability of the HBV-specific immune responses 
elicited by the alternating 2-vector therapy will be explored in healthy (Phase 1a) and virally 
suppressed CHB participants (Phase 1b).

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1.4.
Rationale for the Dose Selection of the Investigational Product 
In the GLP tolerability study (TX-488-2009), 1-vector repeat administration and alternating 
2-vector therapy with 2.65  107 FFU/dose GS-2829 and/or 1.59  107 FFU/dose GS-6779 every 
2 weeks for a total of 6 doses in cynomolgus monkeys were well tolerated and no dose-limiting 
safety signals were identified. 
Administration of the alternating 2-vector therapy with GS-2829 and GS-6779 in cynomolgus 
monkeys every 4 weeks induced robust HBV-specific T-cell responses at both dose levels as 
measured by interferon gamma (IFN-γ) enzyme-linked immunospot assay (ELISpot). The 
cumulative 4 total dose regimen at a frequency of dosing of every 4 weeks elicited the highest 
immune response compared with every 2-week dosing and alternating 2- and 4-week dosing. 
Extension of treatment (one additional dose of 2-vector therapy) had a comparable safety profile 
with a potential increase in the magnitude of the elicited immune response. Please refer to the IB 
for further details on the effect of increasing the number of total doses. 
Starting dose levels for GS-2829 and GS-6779 were selected to achieve a 10-fold lower dose 
than the well-tolerated dose in cynomolgus monkeys, consistent with a lower pharmacodynamic 
effect noted in previous clinical experience with arenavirus vectors using a 10-fold dose range 
{Schwendinger 2022}. In nonhuman primate studies up to the target dose for both vectors, the 
most common vaccination-related adverse effects were transient elevated body temperature and 
edema/erythema at the injection sites. The elevated body temperature was self-limiting and 
resolved by 24 hours postdose, whereas edema/erythema resolved by 72 hours postdose. Further 
details for these studies are provided in the IB.
1.5.
Risk/Benefit Assessment for the Study
Potential risks of a participant’s study involvement include unknown adverse events (AEs), 
general risks associated with frequent clinic visits and laboratory blood draws, local events of 
injection including site pain, swelling, and erythema, as well as systemic events of fatigue, fever, 
arthralgia, myalgia, headache, and nausea. Strategies to mitigate these risks include close 
monitoring of participants’ clinical status, laboratory values, and AEs in the immediate postdose 
period and beyond. Parameters for discontinuation of the investigational product due to AEs will 
be well defined and closely followed.
This is a first-in-human study and there may be unknown risks associated with the 
investigational product. This may include allergic and hypersensitivity reactions and/or 
anaphylaxis, which have been observed in similar vaccines. Due to these risks, sentinel 
participants will be observed at the study site for at least 8 hours after investigational product 
administration on Day 1, and for at least 4 hours following each administration of investigational 
product for all subsequent doses. All other Phase 1a participants will be monitored in the clinic 
for at least 4 hours following each dose of investigational product. Participants in Cohorts 5, 6, 
and 7 will be monitored in the clinic for at least 2 hours following each dose of investigational 
product. Participants may be required to remain in the clinic for additional observation at the 
discretion of the investigator. Participants who experience hypersensitivity or anaphylaxis will 
discontinue the investigational product and will not be rechallenged. The duration of the 
monitoring period may be revised based on recommendations of the Safety Review Team (SRT). 

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As described in Section 1.3, the safety profile will be established in a stepwise manner in healthy 
participants in the Phase 1a portion of the study. Specific information on the study design, safety 
data to be evaluated by the SRT, and stopping rules is detailed in Section 3. In addition to the 
monitoring strategy described previously in this section for this first-in-human study, the 
following will be implemented to support the safety profile and manage the unknown risks 
associated with of the investigational products as monotherapy, combination therapy at low- and 
high-dose levels, and extension of the treatment duration to include an additional administration 
of 2-vector therapy (detailed in Section 3.2, Table 8):
•
The investigational products will be first tested in the monotherapy setting to evaluate the 
safety of repeated low-dose levels of the vectors (Cohorts 1 and 2). 
•
As detailed in Section 3.2, Table 8, alternating 2-vector combination therapy will be 
administered once every 4 weeks and will be first evaluated at the low-dose level (Cohort 3), 
and then at the high-dose level (Cohort 4). 
•
The low-dose level safety profile will be established first in healthy participants (Phase 1a, 
Cohort 3) after a cumulative evaluation of Day 43 safety data (2 weeks after the completion 
of the first dose of the 2-vector combination therapy) and the available cumulative safety data 
from all prior cohorts, before initiating the alternating 2-vector therapy at the high-dose level 
in healthy participants (Cohorts 4 and 8), and the low-dose level in virally suppressed CHB 
participants (Cohort 5, Phase 1b). 
•
The safety profile of the high-dose level will be established in healthy participants (Cohort 4, 
Phase 1a) based on evaluation of Day 43 safety data (2 weeks after completion of the first 
dose of each investigational product of the 2-vector combination therapy) and the available 
cumulative safety data from all prior cohorts, before initiating the high-dose level in virally 
suppressed CHB participants (Cohorts 6 and 7, Phase 1b). 
•
The decision to extend the treatment duration to a third dose of each investigational product 
of 2-vector combination therapy (Cohort 8, Phase 1a and/or Cohort 7, Phase 1b) will be 
based on evaluation of all the Cohort 4 Day 99 (2 weeks after completion of the second dose 
of 2-vector therapy) safety data, in addition to all other available cumulative safety data from 
all dosed cohorts. 
This stepwise, gated approach will mitigate any unknown risks of dose-level increases, and the 
additional dose of alternating 2-vector therapy. Based on the current information (included in the 
IB), it is anticipated that the overall benefit-risk profile is comparable between 2 versus 3 doses 
of 2-vector combination therapy in healthy participants, and participants with CHB. 
Immune-mediated conditions have been reported in some studies and in clinical use of some 
vaccines. In this early-stage protocol, individuals with a history of autoimmune diseases are 
excluded. Investigational product will be stopped for any participant with a new onset or 
worsening of any potentially immune-mediated condition, regardless of assessment of 
relationship to study vaccination. Management of such events will be based on the best available 
local standard of care. A list of potential immune-mediated conditions is provided in 
Appendix 11.7.

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The investigational product has induced HBV-specific immune responses in nonhuman primate 
studies indicating a potential to mediate functional cure in individuals with CHB. There is 
however no clinical data suggesting any known direct benefit to participants in this study. The 
data from this study will, however, support the development of GS-2829 and GS-6779, products 
that when used in combination therapy could help achieve a curative treatment for HBV.
An infectious disease pandemic may pose additional risks to investigational product availability, 
study visit schedule, and adherence to protocol-specified safety- monitoring or laboratory 
assessments. Refer to Appendix 11.3 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
The study objectives and endpoints are outlined in Table 7.
Table 7.
Study Objectives and Endpoints
Primary Objective
Primary Endpoint
•
To evaluate the safety and tolerability of repeated 
dosing of GS-2829 and GS-6779 in healthy 
participants and in virally suppressed participants 
with CHB
•
Proportion of participants with treatment-emergent 
AEs, SAEs, and laboratory abnormalities
Secondary Objective
Secondary Endpoints
•
To evaluate the immunogenicity of repeated 
dosing of GS-2829 and GS-6779 in healthy 
participants and in virally suppressed participants 
with CHB
•
Incidence and magnitude of vaccine-induced 
T-cell responses
Exploratory Objectives
Exploratory Endpoints
•
To further evaluate the T- and B-cell 
immunogenicity and mechanism of action of 
GS-2829 and GS-6779 in healthy participants and 
in virally suppressed participants with CHB
•
Postvaccination changes in T-cell subset 
frequencies and activation status from baseline 
levels 
•
Postvaccination changes in HBV-specific B-cell 
subset frequencies from baseline levels
•
Postvaccination changes in HBV antigen-antibody 
immune complexes from baseline levels 
•
Postvaccination changes in HBV-specific 
antibodies from baseline levels 
•
Postvaccination changes in HBV-specific 
neutralizing antibodies from baseline levels
•
To evaluate the impact of GS-2829 and GS-6779 
on HBV-specific viral biomarkers in participants 
with CHB
•
Change in HBsAg from baseline 
•
Proportion of participants with HBsAg loss with 
or without HBsAg seroconversion 
•
Changes in quantitative HBV RNA, HBV DNA, 
hepatitis B core-related antigen (HBcrAg), 
hepatitis B e antigen (HBeAg), and other HBV 
viral biomarkers from baseline
•
Genomic sequencing of HBV in virally suppressed 
participants as needed
•
To characterize the relationship between 
immunologic changes and circulating HBV viral 
markers
•
Correlation between changes in immunological 
biomarkers and circulating HBV viral markers 
from baseline
•
To evaluate the presence of antivector antibodies 
and their impact on immunogenicity and virologic 
endpoints
•
Postvaccination changes in vector-specific 
antibodies from baseline levels

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3.
STUDY DESIGN
3.1.
Study Design
This protocol describes a blinded, placebo-controlled, randomized Phase 1a and Phase 1b study 
to evaluate the safety, tolerability, and immunogenicity of repeated doses of GS-2829 and 
GS-6779 in healthy participants (Phase 1a) and participants with CHB (Phase 1b). The study will 
comprise 8 cohorts, which will enroll approximately 10 participants each, with a 4:1 
randomization either active viral vectors GS-2829 and/or GS-6779 or PBO. The dosing 
schedules by cohort are provided in Table 8.
Healthy participants aged 18 through 60 years will be enrolled into the Phase 1a part of the 
study; and participants with CHB aged 18 through 65 years will be enrolled into the Phase 1b 
part of the study. To ensure there is enough information to assess any differential for safety and 
tolerability by sex at birth, enrollment of participants of both sexes is encouraged.
An overview of the study design is described below and shown in Figure 1, Figure 2, and 
Figure 3.
The investigational products GS-2829 and GS-6779 are available as ≥ 1.0  107 FFU/mL. There 
are 2 dose levels in this study: high dose (0.5 mL of the undiluted solution) and low dose 
(0.5 mL of the 10-fold dilution of the high dose).
Phase 1a activities will be performed in healthy participants at a single study site. Healthy 
participants will be enrolled into 1 of 5 cohorts to receive the investigational product as follows:
•
Cohort 1 – Single low dose of GS-2829 or PBO on Day 1 and Day 57.
•
Cohort 2 – Single low dose of GS-6779 or PBO on Day 1 and Day 57.
•
Cohort 3 – Single low dose of GS-2829 or PBO on Day 1 and Day 57; and single low dose of 
GS-6779 or PBO on Day 29 and Day 85.
•
Cohort 4 – Single high dose of GS-2829 or PBO on Day 1 and Day 57; and single high dose 
of GS-6779 or PBO on Day 29 and Day 85.
•
Cohort 8 – Single high dose of GS-2829 or PBO on Day 1, Day 57, and Day 113; and single 
high dose of GS-6779 or PBO on Day 29, Day 85, and Day 141.
Phase 1b activities will be performed at multiple study sites (approximately 15) in participants 
diagnosed with CHB who are virally suppressed (Cohort 5, 6, and 7). These participants will be 
enrolled into 1 of 3 cohorts to receive the investigational product as follows:
•
Cohort 5 – Single low dose of GS-2829 or PBO on Day 1 and Day 57; and single low dose of 
GS-6779 or PBO on Day 29 and Day 85.

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•
Cohort 6 – Single high dose of GS-2829 or PBO on Day 1 and Day 57; and single high dose 
of GS-6779 or PBO on Day 29 and Day 85.
•
Cohort 7 - Single high dose of GS-2829 or PBO on Day 1, Day 57 and Day 113; and single 
high dose of GS-6779 or PBO on Day 29, Day 85, and Day 141.
Cohorts 1, 2, and 3
Cohorts 1 and 2 will enroll concurrently and will receive investigational product in 2 groups, a 
sentinel group (2 active and 1 PBO, randomly assigned) and the remainder (6 active and 1 PBO), 
for a total of approximately 10 healthy participants per cohort. Dosing the remainder of 
Cohorts 1 and 2 and initiation of Cohort 3 will commence at the discretion of the investigator in 
consultation with the sponsor’s medical monitor upon evaluation of available safety data through 
at least 14 days after the first dose of investigational product in Cohort 1 and 2 sentinel 
participants. The duration of this review period may be increased based on emerging preliminary 
safety data. Decisions to initiate a higher dose level cohort and any required revisions to postdose 
monitoring will be made upon the review of all available safety data by the SRT.
Cohorts 4 and 5
Initiation of Cohorts 4 and 5, which will run concurrently, will be determined at the discretion of 
the SRT based on the evaluation of available safety data through Day 43 (14 Days after the 
initial dose of both investigational products for all participants enrolled in Cohort 3), in addition 
to all available safety data from Cohorts 1 and 2. The decision on cohort initiation will be based 
on prespecified criteria agreed upon by the SRT and documented in the SRT charter. The 
duration of this review period may be increased based on the emerging and cumulative safety 
data.
Cohort 8
Initiation of Cohort 8 will be determined at the discretion of the SRT based on the evaluation of 
available safety data through Day 43 (14 days after all participants in Cohort 3 have completed 
the initial dose of both investigational products), in addition to all available safety data from 
prior cohorts. Initiation of a third dose of 2-vector combination therapy will be determined at the 
discretion of the SRT based on the evaluation of the available safety data through Day 99 
(14 days after all participants in Cohort 4 have completed the second dose of both investigational 
products), in addition to all available safety data. The decision on cohort initiation will be based 
on prespecified criteria agreed upon by the SRT and documented in the SRT charter. The 
duration of this review period may be increased based on the emerging and cumulative safety 
data. 
Cohort 6
Initiation of Cohort 6 will be determined at the discretion of the SRT based on the evaluation of 
available safety data through Day 43 (14 days after initial dose of both the investigational 
products for all participants enrolled in Cohort 4), available safety data from participants enrolled 

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in Cohort 5, and all available safety data from all dosed cohorts, and dosing will be initiated only 
in the absence of dose-limiting toxicity and/or meeting any prespecified stopping criteria. The 
duration of this review period may be increased based on the emerging and cumulative safety 
data.
Cohort 7
Initiation of Cohort 7 will be determined at the discretion of the SRT based on the evaluation of 
available safety data through Day 43 (14 days after initial dose of both the investigational 
products for all participants enrolled in Cohort 4), available safety data from participants enrolled 
in Cohort 5, and all available safety data from all dosed cohorts. Initiation of the third dose of 
2-vector combination therapy will be determined at the discretion of SRT based on the 
evaluation of the available safety data through Day 99 (14 days after all participants in Cohort 4 
have completed the second dose of both investigational products), in addition to all available 
safety data. The decision on cohort initiation will be based on prespecified criteria agreed upon 
by the SRT and documented in the SRT charter. The duration of this review period may be 
increased based on the emerging and cumulative safety data. 
3.1.1.
Safety Review Team and Charter
An SRT will make decisions on initiating enrollment of higher dose cohorts and initiating the 
third dose of both investigational products based on available safety data in prior study cohorts 
as described in Section 3.1. There will be 3 planned SRT reviews in this protocol. Ad hoc 
reviews can be convened at the discretion of the SRT during the study based on new safety 
concerns and/or the protocol stopping rules (Section 3.3.3).
An SRT charter defining the team membership, meeting conduct, and decision-making process 
will be agreed upon by all team members before the first meeting. The data reviewed at the team 
meetings to make cohort transition decisions will be defined in the charter. The quality control 
checks performed on the data reviewed and used for making these decisions will also be 
described in the charter.
Source data verification may not be performed before SRT meetings. Alternative data quality 
control checks that are performed on data used to make dosing continuation or transition 
decisions are described in the SRT charter.
3.2.
Duration of Dosing
The investigational product will be administered as a single agent or sequential injected doses as 
shown in Table 8.

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Table 8.
Investigational Product Dose Timing
Cohort
1
2
3
4
8
5
6
7
Population
HP
HP
HP
HP
HP
CHB 
(Supp)
CHB 
(Supp)
CHB 
(Supp)
Dose Level
Lowa
Lowa
Lowa
Highb
Highb
Lowa
Highb
Highb
Study Day 1
GS-2829 
or PBO 
IM
GS-
-6779 or 
PBO IM
GS-2829 
or PBO 
IM
GS-2829 
or PBO 
IM
GS-2829 
or PBO 
IM
GS-2829 
or PBO 
IM
GS-2829 
or PBO 
IM
GS-2829 
or PBO 
IM
Study Day 29
GS-6779 
or PBO 
IM
GS-6779 
or PBO 
IM
GS-6779 
or PBO 
IM
GS-6779 
or PBO 
IM
GS-6779 
or PBO 
IM
GS-6779 
or PBO 
IM
Study Day 57
GS-2829 
or PBO 
IM
GS-6779 
or PBO 
IM
GS-2829 
or PBO 
IM
GS-2829 
or PBO 
IM
GS-2829 
or PBO 
IM
GS-2829 
or PBO 
IM
GS-2829 
or PBO 
IM
GS-2829 
or PBO 
IM
Study Day 85
GS-6779 
or PBO 
IM
GS-6779 
or PBO 
IM
GS-6779 
or PBO 
IM
GS-6779 
or PBO 
IM
GS-6779 
or PBO 
IM
GS-6779 
or PBO 
IM
Study 
Day 113
GS-2829 
or PBO 
IM
GS-2829 
or PBO 
IM
Study 
Day 141
GS-6779 
or PBO 
IM
GS-6779 
or PBO 
IM
Total number 
of doses 
(injections)
2
2
4
4
6
4
4
6
CHB = chronic hepatitis B; FFU = focus-forming unit; HP = healthy participant; IM = intramuscular; PBO = placebo; 
Supp = suppressed
a
Low dose = 0.5 mL of a 10-fold dilution of high-dose investigational product.
b
High dose = 0.5 mL of high-dose investigational product (≥ 1.0  107 FFU/mL).
All participants will be followed for safety for 6 months after their last dose of investigational 
product.
3.3.
Protocol-Specific Discontinuation Criteria
GS-2829 and GS-6779 have been evaluated in nonclinical studies without any identified 
dose-limiting toxicity up to the highest proposed dose. In this first in human protocol, the 
following rules will guide early discontinuations from the study.

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3.3.1.
Criteria for Early Discontinuation for the Individual Participant From the 
Investigational Product
Administration of the investigational product should be discontinued in the following instances:
•
If a participant experiences a Grade 3 or higher treatment-emergent AE (TEAE; excluding 
nausea, headache, measured grades of erythema and edema/induration alone) or confirmed 
Grade 3 or higher laboratory abnormality (except for those with a physiologic explanation for 
the events [eg, blood in urine occurring in a menstruating female, creatine phosphokinase 
elevation after strenuous exercise, triglyceride elevation that is nonfasting, etc]) considered 
clinically significant by the investigator and judged as related to the investigational product
•
Any AE, laboratory abnormality or intercurrent illness which, in the opinion of the 
investigator, indicates that continued participation in the study is not in the best interest of the 
participant
•
Participant request to discontinue for any reason
•
Participant noncompliance
•
Pregnancy during the study (refer to Appendix11.4)
•
Loss to follow-up
•
Investigator discretion
•
Discontinuation of the study by the sponsor
If a participant refuses to receive the remaining doses of investigational product as the result of 
an AE that is judged by the investigator as related to investigational product, an early termination 
(ET) visit should be completed, and every attempt should be made to retain the participant in the 
study to continue study evaluations. Following the receipt of any abnormal results believed to be 
related to investigational product at the ET visit, further testing should be repeated weekly or as 
often as deemed clinically appropriate by the investigator until the abnormality resolves, returns 
to baseline visit levels, or is otherwise explained. 
If the participant withdraws consent from the study, the ET evaluations and/or procedures should 
be performed within 7 days of the decision to discontinue from the study.
3.3.2.
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
•
Participant request to discontinue for any reason
•
Participant noncompliance
•
Death 

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3.3.3.
Criteria for Early Discontinuation of a Cohort (Stopping Rules)
3.3.3.1.
Stopping Rules for Cohorts 1 to 4 and 8 (Phase 1a)
Dosing of an individual cohort (ie, 1, 2, 3, 4 or 8) will be suspended when:
•
2 or more participants in each cohort (Cohort 1, 2, or 3) or cohorts with the same high-dose 
level (Cohorts 4 and 8) experience a treatment-emergent, investigational product-related 
Grade 3 or higher clinical AE with the same preferred term (with the exception of headache, 
nausea, measured grades of erythema, or edema/induration)
•
1 or more participants in each cohort (Cohort 1, 2, or 3) or cohorts with the same high-dose 
level (Cohorts 4 and 8) experience a treatment-emergent, investigational product-related SAE
•
2 or more participants in each cohort (Cohort 1, 2, or 3) or cohorts with the same high-dose 
level (Cohorts 4 and 8) experience confirmed treatment-emergent, investigational 
product-related Grade 3 or higher clinically significant laboratory abnormality (as determined 
by the investigator based on clinical evaluation of the participant) unless there is an obvious 
physiological explanation for the event
•
The number and/or severity of AEs justifies discontinuation of the study
Decisions to reinitiate a study cohort will be made by the sponsor in consultation with the 
investigators and pending a safety review by the SRT of all safety data generated in participants 
dosed to date. For individuals already receiving investigational product, the decision whether to 
complete the full course of study treatment will be made by the sponsor with disclosure of new 
information to the study participant.
3.3.3.2.
Stopping Rules for Cohorts 5 to 7 (Phase 1b)
Dosing of an individual cohort (ie, 5, 6, or 7) will be suspended when:
•
2 or more participants in Cohort 5 or cohorts with the same high-dose level (Cohorts 6 and 7) 
experience a treatment-emergent, investigational product-related Grade 3 or higher clinical 
AE with the same preferred term (with the exception of headache, nausea, measured grades 
of erythema, or edema/induration).
•
2 or more participants in Cohort 5 or cohorts with the same high-dose level (Cohorts 6 and 7) 
experience confirmed treatment-emergent, investigational product-related Grade 3 or higher 
clinically significant laboratory abnormality (with the exception of clinically insignificant 
Grade 3 or 4 cholesterol, triglyceride, or glucose). Alanine aminotransferase (ALT) 
elevations without any evidence of hepatic injury are excluded and will be managed and 
followed up based on the guideline provided in Section 7.7.4 and Table 11.
•
The number and/or severity of AEs justifies discontinuation of any study cohort.

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An SRT review of all safety data generated in participants who have received investigational 
product will be initiated. No new participants will be enrolled or initiated on investigational 
product; however, for individuals already receiving the investigational product, the decision 
whether to complete the full course of investigational product will be made by the sponsor, 
investigator, and where applicable or required, by review by regulatory agencies with disclosure 
of new information to the study participants.
3.3.4.
Criteria for Early Termination of the Study
The study will be stopped in the following instances:
•
On recommendation of the SRT based on review of the available safety data
•
Discontinuation of the study at the request of Gilead Sciences (Gilead) or a regulatory agency 
or an independent ethics committee (IEC)
3.3.5.
Reporting a Loss to Follow-Up
Should the participant fail to return to the study site for a scheduled protocol-specified visit, the 
site will need to make at least 3 attempts by a combination of telephone, email, or mail to contact 
the participant. The site must document all attempts to contact the participant. If a participant 
does not respond within 3 months after the initial 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 last visit for the primary endpoint is the date of the last visit to 
perform assessments for the final analysis.
3.4.2.
End of Study
The end of the study is defined as the last participant’s last observation (or visit).
3.5.
Source Data
The source data for this study will be obtained from the participating sites, central laboratory, 
specialty laboratory, the Interactive Response Technology (IRT), and/or other vendors as 
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4.
PARTICIPANT POPULATION
4.1.
Number of Participants and Participant Selection
Approximately 80 unique participants will be enrolled in the study; study participants will 
include male and nonpregnant, nonlactating, female participants aged 18 through 60 years in 
Phase 1a cohorts, and aged 18 through 65 years in Phase 1b cohorts. As described in Section 3.1, 
participants who will be enrolled in:
•
Phase 1a cohorts will be healthy participants 
•
Phase 1b cohorts will have confirmed CHB and will be virally suppressed 
Enrollment of participants of both sexes is encouraged. Participants will be enrolled from several 
sites across the countries where the study will be conducted. Within these countries, recruitment 
efforts will be broad enough to capture a fair representation of the population but, due to the 
small sample size per study cohort, no specific quotas will be provided by race and/or ethnicity.
4.1.1.
Participant Replacement
If necessary, replacement participants may be enrolled after discussion and approval from Gilead 
if a current participant is considered nonevaluable. Replacement participants will not be enrolled 
for participants who discontinue the study due to investigational product-related AEs. Sites will 
be encouraged to make efforts to retain all individuals who may wish to discontinue the study 
due to AEs. Ideally, such participants will receive no further investigational product but will 
continue all visits on schedule.
The primary outcome of interest in this study is the safety and tolerability of GS-2829 and 
GS-6779 used in combination, so participants who receive only 1 of the 2 vectors and 
discontinue the study for non-AE related reasons and participants requiring prolonged systemic 
steroid therapy may be replaced to ensure the collection of evaluable data but will be encouraged 
to remain on study for evaluation of safety. 
4.2.
Phase 1a Healthy Participant Inclusion/Exclusion Criteria
4.2.1.
Inclusion Criteria
Phase 1a participants must meet all of the following inclusion criteria at screening (or as stated 
otherwise) to be eligible for participation in this study:
1) Have the ability to understand and sign a written informed consent form (ICF), which must 
be obtained prior to initiation of study procedures.
2) Assigned male sex at birth or female sex at birth (and be nonpregnant and nonlactating).

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3) Participants assigned male at birth and participants assigned female at birth and of 
childbearing potential who engage in heterosexual intercourse must agree to use 
protocol-specified methods of contraception as described in Appendix 11.4.
4) Be aged 18 through 60 years, inclusive, at enrollment.
5) Have a calculated body mass index (BMI) of ≤ 32.0 kg/m2.
6) Must, in the opinion of the investigator, be in good health based upon medical history and 
physical examination, including vital signs. 
7) Laboratory evaluations and 12-lead electrocardiogram (ECG) evaluations must be without 
clinically significant abnormalities as assessed by the investigator.
8) Nondiabetic with a hemoglobin A1c < 6.5%.
9) Must be willing and able to comply with all study requirements.
10) No prior history of HBV infection with a negative HBsAg and hepatitis B core antibody.
11) Have liver biometric tests such as ALT, aspartate aminotransferase (AST), alkaline 
phosphatase (ALP), and total bilirubin at or below the upper limit of normal (ULN).
12) Have a calculated creatinine clearance (CLcr) of at least 90 mL/min (using the 
Cockcroft-Gault method {Cockcroft 1976}) based on serum creatinine and actual body 
weight as measured for:
•
Participant assigned male at birth:
(140 − Age [years])  (Weight [kg]) = CLcr (mL/min)
72  (Serum Creatinine [mg/dL])
•
Participant assigned female at birth: (140 − Age [years])  (Weight [kg])  0.85 = CLcr (mL/min)
72  (Serum Creatinine [mg/dL])
4.2.2.
Exclusion Criteria
Phase 1a participants who meet any of the following exclusion criteria at screening will not be 
enrolled in this study:
1) Have any serious or active medical or psychiatric illness (including depression) that, in the 
opinion of the investigator, would interfere with participant treatment, assessment, or 
compliance with the protocol. This would include renal, hepatic, cardiac, hematological, 
pulmonary (including chronic asthma), endocrine (including diabetes), central nervous, 
gastrointestinal (including an ulcer), vascular, metabolic (thyroid disorders, adrenal disease), 
immunodeficiency disorders, active infection, or malignancy that are clinically significant or 
requiring treatment.
2) History or evidence of autoimmune disease or known immunodeficiency of any etiology.

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3) Have a history of any of the following:
a) Significant serious skin disease, such as but not limited to rash, food allergy, eczema, 
psoriasis, or urticaria.
b) Significant drug sensitivity or drug allergy (such as anaphylaxis or hepatoxicity).
c) Known hypersensitivity to the investigational product, metabolites, or to formulation 
excipients (see Section 5).
d) Significant cardiac disease (including history of myocardial infarction based on ECG 
and/or clinical history, any history of ventricular tachycardia, congestive heart failure, or 
dilated cardiomyopathy with left ventricular ejection fraction ≤ 40%); or a family history 
of long QT syndrome, or unexplained death in an otherwise healthy individual between 
the ages of 1 and 30 years.
e) Severe peptic ulcer disease, gastroesophageal reflux disease, or other gastric acid 
hypersecretory conditions requiring prolonged (≥ 6 months) medical treatment.
4) Cancer diagnosis within 5 years prior to study entry, other than squamous or basal cell 
carcinoma of the skin. Participants under evaluation for possible malignancy are not eligible.
5) Current diagnosis of HIV or hepatitis C virus (HCV). Participants who test positive for HCV 
antibody will require HCV RNA testing by quantitative polymerase chain reaction (PCR) for 
confirmation of active disease. Participants who are HCV antibody positive, but have a 
documented negative HCV RNA are eligible. 
6) Use of any systemic antibiotics within 30 days of screening.
7) Receipt of any HBV vaccine within 12 months of screening visit or planning HBV 
vaccination during the study period.
8) Receipt of any investigational product within 3 months or vaccine within 3 months of 
screening (with the exception of influenza and SARS-CoV-2 vaccines, which if needed, 
should be administered at least 14 days before or after an investigational product 
administration).
9)
Receipt of immunoglobulin or other blood products withing 3 months of screening.
10) Have current alcohol or substance abuse history judged by the investigator to potentially 
interfere with participant compliance.
11) Positive serum pregnancy test at screening or positive urine pregnancy on Day 1 
(Appendix 11.4).
12) Male participants unwilling to refrain from sperm donation during and until at least 6 months 
after the last dose of investigational product. 

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13) Female participants unwilling to refrain from egg donation and in vitro fertilization during 
and until at least 6 months after the last dose of investigational product.
14) Have poor venous access that limits phlebotomy.
15) Have taken any prescription medications or over-the-counter medications, including herbal 
products, within 28 days prior to start of investigational product dosing, with the exception of 
vitamins and/or acetaminophen and/or ibuprofen and/or hormonal contraceptive medications.
16) Have been treated with systemic steroids, immunosuppressant therapies, or chemotherapeutic 
agents within 3 months prior to screening or is expected to receive these agents during the 
study (eg, corticosteroids, immunoglobulins, other immune or cytokine-based therapies).
17) Requirement for ongoing therapy with or prior use of any prohibited medications listed in 
Section 5.6.1.
18) Participation in any other clinical study (including observational studies) without prior 
approval from the sponsor is prohibited while participating in the study.
19) Believed by the investigator to be inappropriate for study participation for any reason not 
otherwise listed.
4.3.
Phase 1b Virally Suppressed CHB Participant Inclusion/Exclusion Criteria
4.3.1.
Inclusion Criteria
Phase 1b participants must meet all of the following inclusion criteria at screening (or as stated 
otherwise) to be eligible for participation in this study:
1) Have the ability to understand and sign a written ICF, which must be obtained prior to 
initiation of study procedures.
2) Assigned male sex at birth or female sex at birth (and be nonpregnant and nonlactating).
3) Participants assigned male at birth and participants assigned female at birth and of 
childbearing potential who engage in heterosexual intercourse must agree to use 
protocol-specified methods of contraception as described in Appendix11.4
4) Be aged 18 through 65 years, inclusive, at enrollment.
5) Have a calculated BMI of ≤ 32.0 kg/m2.
6) Documented evidence of CHB based on one of the following:
a) Positive HBsAg or HBV DNA at least 6 months prior to the screening visit; OR 
b) Historical liver biopsy consistent with CHB infection available.

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7) Quantitative HBsAg greater than the LLOQ and ≤ 5000 IU/mL at screening. 
8) Have no evidence of advanced fibrosis by FibroScan (defined as FibroScan < 9 kPa within 
6 months of screening). If a historical FibroScan is not available, this can be done at 
screening.
9) 12-lead ECG evaluations must be without clinically significant abnormalities as assessed by 
the investigator.
10) Nondiabetic with a hemoglobin A1c < 6.5%.
11) Must be willing and able to comply with all study requirements.
12) Have a calculated CLcr of at least 60 mL/min (using the Cockcroft-Gault method {Cockcroft 
1976}) based on serum creatinine and actual body weight as measured for:
•
Participant assigned male at birth:
(140 − Age [years])  (Weight [kg]) = CLcr (mL/min)
72  (Serum Creatinine [mg/dL])
•
Participant assigned female at birth: (140 − Age [years])  (Weight [kg])  0.85 = CLcr (mL/min)
72  (Serum Creatinine [mg/dL])
13) Alanine aminotransferase < 3  ULN; international normalized ratio (INR) ≤ ULN; 
albumin ≥ 3.5 g/dL; direct bilirubin ≤ 1.5  ULN; platelets within the normal limit. 
14) Must have received an approved HBV-active oral antiviral agent for ≥ 6 months prior to 
screening with HBV DNA below LLOQ for ≥ 3 months prior to screening and with no plan 
to stop HBV-active antivirals during the study.
4.3.2.
Exclusion Criteria
Phase 1b participants who meet any of the following exclusion criteria at screening will not be 
enrolled in this study:
1) Have any serious or active medical or psychiatric illness (including depression) that, in the 
opinion of the investigator, would interfere with participant treatment, assessment, or 
compliance with the protocol. This would include renal, cardiac, hematological, pulmonary 
(including chronic asthma), endocrine (including diabetes), central nervous, gastrointestinal 
(including an ulcer), vascular, metabolic (thyroid disorders, adrenal disease), 
immunodeficiency disorders, active infection, or malignancy that are clinically significant or 
requiring treatment.
2) History or evidence of autoimmune disease or known immunodeficiency of any etiology.
3) Have a history of any of the following:
a) Significant serious skin disease, such as but not limited to rash, food allergy, eczema, 
psoriasis, or urticaria.

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b) Significant drug sensitivity or drug allergy (such as anaphylaxis or hepatoxicity).
c) Known hypersensitivity to the investigational product, metabolites, or to formulation 
excipients (see Section 5).
d) Significant cardiac disease (including history of myocardial infarction based on ECG 
and/or clinical history, any history of ventricular tachycardia, congestive heart failure, or 
dilated cardiomyopathy with left ventricular ejection fraction ≤ 40%); or a family history 
of long QT syndrome, or unexplained death in an otherwise healthy individual between 
the ages of 1 and 30 years.
4) Cancer diagnosis within 5 years prior to study entry, other than squamous or basal cell 
carcinoma of the skin. Participants under evaluation for possible malignancy are not eligible.
5) Current diagnosis of HIV, HCV, or hepatitis D virus (HDV). Participants who test positive 
for HCV antibody will require HCV RNA by quantitative PCR for confirmation of active 
disease. Participants with a known history of HCV or a positive HCV antibody test will not 
require an HCV antibody at screening and will only require HCV RNA by quantitative PCR 
for confirmation of active disease.
6) Use of systemic antibiotics within 30 days of screening.
7) Receipt of any HBV vaccine within 12 months of screening visit or planning HBV 
vaccination during the study period.
8) Receipt of any investigational product within 3 months or vaccine within 3 months of 
screening (with the exception of influenza and SARS-CoV-2 vaccines, which if needed, 
should be administered at least 14 days before or after an investigational product 
administration).
9) Receipt of solid organ or bone marrow transplant.
10) Receipt of immunoglobulin or other blood products within 3 months of screening.
11) Have current alcohol or substance abuse history judged by the investigator to potentially 
interfere with participant compliance.
12) Positive serum pregnancy test at screening or positive urine pregnancy on Day 1 
(Appendix 11.4).
13) Male participants unwilling to refrain from sperm donation during and until at least 
6 months after the last dose of investigational product. 
14) Female participants unwilling to refrain from egg donation and in vitro fertilization during 
and until at least 6 months after the last dose of investigational product.
15) Have poor venous access that limits phlebotomy.

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16) Have taken any over-the-counter medications, including herbal products, within 28 days 
prior to start of investigational product dosing, with the exception of vitamins and/or 
acetaminophen and/or ibuprofen and/or hormonal contraceptive medications.
17) Have been treated with systemic steroids, immunosuppressant therapies, or 
chemotherapeutic agents within 3 months prior to screening or is expected to receive these 
agents during the study (eg, corticosteroids, immunoglobulins, other immune or 
cytokine-based therapies).
18) Requirement for ongoing therapy with or prior use of any prohibited medications listed in 
Section 5.6.1.
19) Participation in any other clinical study (including observational studies) without prior 
approval from the sponsor is prohibited while participating in the study.
20) Believed by the investigator to be inappropriate for study participation for any reason not 
otherwise listed.

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5.
STUDY INTERVENTIONS AND CONCOMITANT 
MEDICATIONS
5.1.
Randomization, Blinding, and Treatment Code Access
5.1.1.
Randomization 
Participants will be assigned a screening number in the IRT system at the time of consent.
Once eligibility has been confirmed, the investigator or designee will randomize the participant 
using the IRT system. Eligible participants will be randomized in a 4:1 ratio to receive GS-2829 
and/or GS-6779, or PBO starting on Day 1. It is the responsibility of the investigator to ensure 
that the participant is eligible for the study prior to enrollment. 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 the Day 1 visit 
provided all screening procedures have been completed and participant eligibility has been 
confirmed. 
If necessary, replacement participants may be enrolled after discussion and approval from the 
sponsor (Section 4.1.1). A new unique participant number will be assigned to the replacement 
participant.
Participation in any other clinical study (including observational studies) without prior approval 
from the sponsor is prohibited while participating in this study. 
5.1.2.
Blinding 
This study is designed as a randomized and blinded study, in which Gilead personnel including 
the medical monitor, Gilead contracted study monitors, and the site pharmacists (or designee), 
will be unblinded while the investigational site personnel and study participants will remain 
blinded. To mitigate the risks of inadvertently releasing the treatment information, Gilead 
personnel will only be provided with the unblinded information when there is a need to access 
such information based on their function or role for data analysis to support dose determination 
or safety monitoring. Individuals in Clinical Packaging and Labeling or Clinical Supply 
Management may have an Unblinded Inventory Manager role in the IRT for purposes of 
investigational product inventory management. Individuals in Patient Safety (PS) who are 
responsible for safety signal detection, investigational new drug safety reporting, and/or 
expedited reporting of suspected unexpected serious adverse reactions (SUSARs) may be 
unblinded to individual case data and/or group-level summaries. Should Gilead personnel receive 
unblinded information, they will maintain the confidentiality of the unblinded information and 
will not communicate the information to blinded site personnel or participants. The blinding will 
be preserved at the participant level, the group level summaries without revealing the individual 
participant treatment assignment may be provided to the investigator without further 
documentation.

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5.1.3.
Procedures for Breaking the Blind on Treatment Codes
In the event of a medical emergency where breaking the blind is required to provide medical care 
to the participant, the investigator may obtain the treatment assignment for that participant from 
the IRT system. The sponsor recommends but does not require that the investigator contact the 
Gilead medical monitor before breaking the blind. Treatment assignment should remain blinded 
unless that knowledge is necessary to determine participant emergency medical care. The 
rationale for unblinding must be clearly explained in source documentation, along with the date 
on which the treatment assignment was obtained. The investigator is requested to contact the 
Gilead medical monitor promptly in case of any treatment unblinding.
Blinding of study treatment is critical to the integrity of this clinical study. Therefore, if a 
participant’s treatment assignment is disclosed to the investigator, the participant will have study 
treatment discontinued. All participants will be followed until study completion unless consent to 
do so is specifically withdrawn by the participant.
5.2.
Description and Handling of the Investigational Product 
5.2.1.
Formulation
GS-2829 drug product is formulated as a sterile, preservative-free solution intended for 
intramuscular administration. The drug product is composed of ≥ 1.0  107 FFU/mL GS-2829 in 
N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES), sodium chloride, glycine, 
poloxamer 188, and recombinant human serum albumin (rHSA).
GS-6779 drug product is formulated as a sterile, preservative-free solution intended for 
intramuscular administration. The drug product is composed of ≥ 1.0  107 FFU/mL GS-6779 in 
HEPES, sodium chloride, glycine, poloxamer 188, and rHSA. 
Placebo for GS-2829 and GS-6779 has the same inactive ingredients as GS-2829 and GS-6779. 
5.2.2.
Packaging and Labeling
The investigational products will be supplied in single-use 2R Type I clear glass vials, with 
elastomeric stoppers, and capped with aluminum seals with polypropylene flip-off caps.
Investigational products to be distributed to centers in participating countries shall be labeled to 
meet applicable requirements of the United States Food and Drug Administration (FDA), 
European Union (EU) Guideline to Good Manufacturing Practice - Annex 13 (Investigational 
Medicinal Products), and/or other local regulations.
5.2.3.
Storage and Handling
All investigational products should be stored at ≤ −65 °C and protected from light. Storage 
conditions are specified on the investigational product labels. 

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Until dispensed to the participant, all investigational products should be stored in a securely 
locked area, accessible only to authorized site personnel. To ensure stability and proper 
identification, the investigational product should be stored in the containers in which it is 
supplied until preparation for dosing to the participant.
5.3.
Dosage and Administration 
Following completion of screening assessments, eligible participants will be administered 
GS-2829 and/or GS-6779 or PBO in the schedule provided in Table 8. 
Investigational product or PBO will be administered at 0.5 mL intramuscularly into the deltoid 
muscle of the arm at the following doses:
•
GS-2829 – Low dose will be prepared as a 10-fold dilution of the high-dose investigational 
product
•
GS-6779 – Low dose will be prepared as a 10-fold dilution of the high-dose investigational 
product
•
GS-2829 – High dose will be ≥ 0.5  107 FFU (0.5 mL of the investigational product 
provided at ≥ 1.0  107 FFU/mL)
•
GS-6779 – High dose will be ≥ 0.5  107 FFU (0.5 mL of the investigational product 
provided at ≥ 1.0  107 FFU/mL)
Investigational product or PBO is to be administered after baseline evaluations are completed, as 
indicated in Table 1, Table 2, and Table 3. Females of childbearing potential will require a urine 
pregnancy test performed on the day of administration to confirm nonpregnant status prior to 
dosing. 
Sentinel group participants are to be monitored in the clinic for at least 8 hours following the first 
administration of investigational product. All subsequent doses for the sentinels and all other 
Phase 1a participants will be monitored in the clinic for at least 4 hours following each dose of 
investigational product. Participants in Cohorts 5 to 7 will be monitored in the clinic for at least 
2 hours following each dose of investigational product. Participants may be required to remain in 
the clinic for additional observation at the discretion of the investigator. 
Participants in Cohorts 5 through 7 will also receive ongoing treatment with NAs (approved 
HBV oral antivirals), which are considered AxMPs for this study. Self-administered tenofovir 
and entecavir-based therapies are allowed at doses used for standard of care.
5.4.
Fasting and Meals
No fasting or alteration of diet is required prior to administration of the investigational product.

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5.5.
Dispensing, Accountability, and Disposal or Return of Investigational 
Products 
The investigator (or designee, eg, study site pharmacist) will acknowledge receipt of the 
investigational product (after reviewing the shipment’s content and condition). The investigator 
(or designee) will maintain an accurate inventory of all investigational product(s). Each dose of 
the investigational product(s) administered at the study site will be administered by qualified 
study site staff. The dose of investigational product(s) administered to participants in the clinic 
under the supervision of staff will be accurately recorded on the Investigational Product 
Accountability form provided by Gilead (or on equivalent documentation maintained by the 
study site), which indicates the date and quantity of each dosage formulation dispensed to 
individual participants.
Gilead recommends that used and unused investigational products should be destroyed at the 
site. If the site has an appropriate standard operating procedure for investigational product 
destruction as determined by Gilead, the site may destroy used (empty or partially empty) and 
unused investigational products 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 investigational products are destroyed on site, the investigator must maintain 
accurate records for all investigational products that are destroyed. Records must show the 
identification and quantity of each unit destroyed, the method of destruction, and the person who 
disposed of the investigational product. Upon study completion, copies of the investigational 
product accountability records must be filed at the site. Another copy will be returned to Gilead. 
If the site does not have an appropriate procedural document for investigational product 
destruction, used and unused investigational products are to be sent to the designated disposal 
facility for destruction. The study monitor will provide instructions for return.
The study monitor will review investigational product supplies and associated records at periodic 
intervals.

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5.6.
Concomitant Medications and Other Protocol Restrictions
5.6.1.
Concomitant Medications
Table 9.
Prohibited and Cautionary Medications
Medication Class
Medications to Be Used With 
Caution
Prohibited Medications
Vaccines
Elective standard-of-care vaccines 
(eg, influenza and SARS-CoV-2) will 
need to be spaced by at least 14 days 
before or after an investigational 
product administration when possible.
Any vaccine within 3 months of screening, 
hepatitis B vaccine formulations other than 
the study product within 12 months of 
screening and during the study period, and 
live vaccines (including live influenza 
vaccines) during the study period
Immunosuppressive 
agents
Topical steroids for skin rash and 
other relevant conditions are allowed 
during the study. Short-term systemic 
steroids for ≤ 14 days are allowed for 
managing AEs that occur on protocol.
Systemic steroids up to 8 weeks after the last 
investigational product dose, 
immunosuppressive therapies, or 
chemotherapeutic agents prior to screening, 
immunoglobulins and other immune of 
cytokine-based therapies, within 3 months of 
screening and during the study period. Any 
such use will require sponsor’s approval 
whenever possible.
Immunomodulators and 
monoclonal antibodies
Any use of SARS-CoV-2 monoclonal 
antibodies during the course of the 
study will need to be reported to the 
sponsor.
Previous use within 12 months of screening 
or current use of humanized or human 
monoclonal or polyclonal antibodies, and 
immunomodulators such as tacrolimus, 
cyclosporine, methotrexate, sulfasalazine 
etc.
Antibiotics
During the treatment phase and up to 
8 weeks after last dose of the 
investigational product, treatment of 
acute infections with systemic 
antibiotics.
Use of systemic antibiotics within 30 days of 
screening.
NSAIDs
Encouraged to avoid use of NSAIDs 
up to 3 days after each investigational 
product administration.
Not applicable.
Herbal supplements
Not applicable.
All use prohibited up to 8 weeks after last 
dose of investigational product except with 
sponsors approval.
NSAIDs = nonsteroidal anti-inflammatory drugs; SARS-CoV-2 = severe acute respiratory syndrome coronavirus 2
The following agents are excluded while participants are in the study (from screening until the 
last study visit, as appropriate):
•
Any and all illegal or illicit drug use, including use of prescription drugs outside the care of 
the prescribing physician.
•
Recreational or medical cannabinoids or derivatives.

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Use of a concomitant medication must be reported on the appropriate electronic case report 
forms (eCRF).
If a participant requires use of a prohibited medication, a request for such use must be reviewed 
by the sponsor and if approved, participants may continue to participate in the study. Decisions 
on the use of cautionary medications will need to follow protocol specifications as documented 
in Table 9.
There is no substantial safety data regarding the concomitant administration of the SARS-CoV-2 
vaccines, influenza vaccines, and GS-2829 and GS-6779. Participants are allowed to receive the 
SARS-CoV-2 vaccine; however, administering such vaccines within 14 days of investigational 
product should be avoided. Participants should be encouraged to receive any needed vaccinations 
prior to enrollment. Study visits should continue as planned if vaccination occurs while the 
participant is on the study. Investigators should follow local guidelines for concomitant 
administration of the SARS-CoV-2 vaccines with the investigational product. 
5.6.2.
Other Protocol Restrictions
Participants will be encouraged to avoid strenuous or prolonged exercise, as well as saunas, 
steam baths, and sunbathing or other prolonged ultraviolet exposure (eg, in a tanning salon) from 
the screening evaluation until completion of the last study visit, as these activities are known to 
affect certain clinical laboratory test parameters (eg, creatine kinase [CK]) and will provide false 
indicators of a potentially treatment-related toxicity. 
Upon every visit to the clinic, each participant will be questioned as to their compliance with the 
above protocol restrictions. If a participant is unable to comply with any of the restrictions 
described above, the participant’s continued participation in the study will be reevaluated by the 
investigator in consultation with the sponsor.

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STUDY ASSESSMENTS 
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The study procedures to be conducted for each paiticipant emolled in the study are presented in 
tabulai· f01m in Table 1, Table 2, and Table 3 and ai·e described in the sections below. 
Any deviation from protocol procedures should be noted in the paiticipant's clinical chart and 
appropriate eCRFs. In addition, the sponsor should be promptly notified of any protocol 
deviations. 
The study sites will not initiate dosing until the following have all been met: 
• 
The IEC or other applicable regulato1y agencies have reviewed and approved the study and 
the info1med consent document. 
• 
All requested regulato1y doclllllents have been submitted to and approved by Gilead. 
• 
A master services agreement and/or study agreement is executed. 
• 
The study initiation meeting has been conducted by Gilead (or designee). 
A study initiation meeting will include but is not limited to a review of the protocol, the IB, 
investigational product, and investigator responsibilities. 
Doclllllentation of the personally signed and dated ICF for each participant, using the 
study-specific, !EC-approved ICF, is required before initiating the screening process. 
6.1. 
Informed Consent 
Written info1med consent (Section 9 .1.4) must be obtained from each paiticipant before initiation 
of any screening procedure. After a paiticipant has provided infonned consent, the investigator 
and other study personnel will dete1mine if the paiticipant is eligible for paiticipation in the 
study (Section 6.3.2). 
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6.2.
Participant Enrollment and Treatment Assignment
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.
It is the responsibility of the investigator to ensure that participants are eligible to participate in 
the study prior to enrollment and continue to remain eligible throughout the study.
Once the ICF has been obtained, all screening tests and evaluations have been assessed, and 
study eligibility has been confirmed, participants will be enrolled to receive investigational 
product on Day 1. Baseline assessments as well as confirmation of negative urine pregnancy 
tests in women of childbearing potential will need to be completed prior to dosing. 
Participants will receive the study treatment assignments as described in Section 5.3 and Table 8.
6.3.
Instructions for Study Procedures
6.3.1.
Adverse Events
From the time informed consent is obtained through the first administration of investigational 
product, record all 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 
investigational product administration, report all AEs and SAEs. Evaluation of AEs will occur at 
the visits shown in Table 1, Table 2, and Table 3. See Section 7 for additional details.
6.3.2.
Screening Assessments
A sufficient number of participants will be screened to identify the planned number of 
participants for randomization.
Screening laboratory assessments may be repeated once within 45 days prior to administration of 
investigational product for exclusionary laboratory values if, in the investigator’s opinion, one of 
the following are met: there is reason to believe the retest value will be within accepted 
parameters, if the initial value was deemed to be inaccurate or inconsistent with the participant’s 
previous result(s), if the initial value was generated in error (eg, mishandled sample), or there is 
another relevant extenuating circumstance. In any instance, the site should obtain approval from 
Gilead prior to repeating the laboratory assessment.
Participants should be instructed to fast (no food or drink, except water), starting from midnight 
(00:00) or earlier, as appropriate, on the evening prior to the screening visit to ensure an 
approximate 8-hour fast prior to the fasted blood sample collection the next morning.

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The screening assessment will include a review of the inclusion/exclusion criteria (Sections 4.2 
and 4.3) and completion of all screening procedures as outlined in Table 1, Table 2, and Table 3. 
Eligible participants meeting all of the inclusion criteria and none of the exclusion criteria will be 
instructed on all protocol requirements.
6.3.3.
Treatment Assessments
Study procedures and assessments are outlined in Table 1, Table 2, and Table 3.
Sentinel group participants are to be monitored in the clinic for at least 8 hours following the first 
administration of investigational product. All subsequent doses for the sentinels and all other 
Phase 1a participants will be monitored in the clinic for at least 4 hours following administration 
of investigational product. Participants in Cohorts 5 through 7 will be monitored in the clinic for 
at least 2 hours following the administration of investigational product. Participants may be 
required to remain in the clinic for additional observation at the discretion of the investigator. At 
the end of this observation period, participants will need to be assessed for any postinjection 
reactions and AEs, any reportable events will need to be recorded in the eCRF.
Participants will be contacted by phone on the following days to review protocol restrictions, 
AEs, any concomitant medication usage, and completion of their participant diaries:
Cohorts 1 and 2: Days 2, 3, 58, and 59.
Cohorts 3, 4, 5, and 6: Days 2, 3, 30, 31, 58, 59, 86, and 87.
Cohorts 7 and 8: Days 2, 3, 30, 31, 58, 59, 86, 87, 114, 115, 142, and 143.
6.3.4.
Participant Diaries for Reactogenicity
Participants will be asked to record potential investigational product reactions based on solicited 
events via a diary for 7 days following each administration of investigational product. Review of 
participant reactogenicity data will occur at the next visit that is greater than 7 days postdose 
(Table 1, Table 2, and Table 3). Solicited events will include, but may not be limited to, 
temperature, local events of injection-site pain, swelling, erythema, induration, and systemic 
events of fatigue, fever, arthralgia, myalgia, headache, and nausea. Any reactogenicity event that 
meets the criteria for AEs based on Section 7.1.1 must be reported in the appropriate eCRF.
6.3.5.
Clinical Virology
6.3.5.1.
Sample Collection for Antivector Antibody Evaluation 
The incidence of antivector antibodies against GS-2829 and GS-6779 may be assessed in 
samples collected at the time points shown in Table 1, Table 2, and Table 3. Samples that are 
found to be positive for antivector antibodies may be further characterized. 

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6.3.5.2.
HBV Viral Biomarkers
Phase 1b only: HBV viral biomarkers (HBsAg, HBV DNA, HBV RNA, HBcrAg, and HBeAg) 
will be collected at the time points indicated in Table 2 and Table 3 and evaluated as needed. 
6.3.5.3.
Sample Collection for Genomic Sequencing
Phase 1b only: Blood samples from virally suppressed participants will be collected for genomic 
sequencing and genotyping of HBV at the time points indicated in Table 2 and Table 3 and 
evaluated as needed.
6.3.6.
Sample Collection for Biomarker Evaluation
6.3.6.1.
Biomarker Samples to Address the Study Objectives 
Biological specimens will be collected from all participants who have provided consent to 
participate in this study and may be used to evaluate the association of systemic and/or 
tissue-based biomarkers with investigational product response and dosage selection, and to better 
understand drug-induced biological pathways and/or HBV biology.
Because biomarker science is a rapidly evolving area of investigation, and AEs in particular are 
difficult to predict, it may not be possible to prospectively specify all tests that may be done on 
the specimens provided. The specific analyses will include, but may not be limited to, the 
biomarkers and assays listed below. The testing outlined below is based upon the current state of 
scientific knowledge. It may be modified during or after the end of the study to remove tests no 
longer indicated and/or to add new tests based upon new state-of-the-art knowledge.
Blood samples will be collected to measure biomarkers that will include, but may not be limited 
to:
•
investigational product-induced T-cell responses by IFN-γ ELISpot
•
phenotype and function of HBV-specific T-cell and B-cell responses 
•
peripheral soluble protein (including cytokines, chemokines, and inflammatory markers)
•
HBV-targeted antibody responses 
Samples will be collected at the time points outlined in Table 1, Table 2, and Table 3. A more 
detailed breakdown of the biomarker assays is also provided in Table 4, Table 5, and Table 6.
Samples collected for biomarker assessments will be destroyed no later than 20 years after the 
end of the study or per country requirements (Section 9.1.4).

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Safety Assessments 
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Safety will be evaluated throughout the study. Refer to Table 1, Table 2, and Table 3 for a 
schedule of safety assessments. 
6.4.1. 
Electrocardiogram Assessment 
Recording of the ECG will occur at screening (Table 1, Table 2, and Table 3). 
Paiiicipants should rest quietly in the supine position for a minimum of 10 minutes prior to each 
scheduled 12-lead ECG acquisition and should remain in that position until the recording is 
complete. 
The investigator or other qualified individual at the study center will review the ECG for 
abnonnalities. 
Collection of additional ECGs for routine safety monitoring at additional time points or days is at 
the discretion of the investigator based on GCP. 
6.4.2. 
Physical Examination 
Physical examinations conducted throughout the study will be a complete physical examination 
or a symptom-driven physical examination, as outlined in Table 1, Table 2, and Table 3. The 
complete physical examination conducted at screening will also include the following 
assessments: 
• 
General appeai·ance, and the following body systems: head, neck, thyroid, eyes, eai·s, nose, 
throat, mouth, and tongue; chest (excluding breasts); respirato1y, cardiovasculai·; lymph 
nodes; abdomen; skin, hair, nails; musculoskeletal; neurological. Genitourinai·y and breast 
examinations should not be conducted unless clinically indicated. 
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•
Review medical history, including history of allergies, prior and current use of nicotine or 
nicotine-containing products, alcohol and illegal/illicit drug use, and prior and current (within 
30 days) medication use.
6.4.3.
Vital Signs
Vital sign measurements include blood pressure, heart rate, and body temperature and should be 
collected once participants have been seated or are in the supine position. Participant position for 
measurement should be kept consistent throughout the study. Refer to Table 1, Table 2, and 
Table 3 for vital signs collection time points.
6.4.4.
Body Mass Index
Height (cm) and weight (kg) will be collected at screening for calculation of BMI for inclusion 
criteria.
6.4.5.
Clinical Laboratory Tests/Assessments
Blood and urine samples for safety evaluations will be collected throughout the study as outlined 
in Table 1, Table 2, and Table 3.
No fasting or alteration of diet is required for this study, with the exception of fasting prior to the 
collection of laboratory assessments performed for screening. Participants should be instructed to 
fast (no food or drink, except water), starting from midnight (00:00) or earlier, as appropriate, on 
the evening prior to the screening visit to ensure an approximate 8 hour fast prior to the fasted 
blood sample collection the next morning.

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Table 10.
Laboratory Analytes
Safety Laboratory Measurements
Chemistry
(Serum or Plasma)
Hematology
Urinalysis
Other Laboratory Measurements
ALP
AST
ALT
GGT
Total bilirubin
Direct and indirect 
bilirubin
Total protein
Albumin
Lactate dehydrogenase
Bicarbonate
BUN
Calcium
Chloride
Creatinine
Glucose
Hemoglobin A1c
Phosphorus
Magnesium
Potassium
Sodium
Lipase
Total cholesterol
High-density 
lipoprotein
Low-density lipoprotein
Triglycerides
CPK/CK
Uric acid
CBC with 
differential, and 
platelets
Coagulation panel, 
including 
prothrombin time, 
aPTT, and INR
Color and clarity
Specific gravity
pH
Glucose
Protein
Blood and 
microscopic (reflex if 
positive)
Leukocyte esterase 
and microscopic 
(reflex if positive)
Serum pregnancy test
Urine pregnancy test
Serum FSH
Plasma HBV DNA, HBV RNA, 
HBV surface antigen
HBV surface antibody
HBV core-related antigen
HBeAg
HBeAb
HIV serology
HDV antibody
HCV antibody serology reflex to 
HCV RNA
HBV immunogenicity (IFN-γ 
ELISpot assay)
HBV-1-specific T-cell phenotype 
and function
Peripheral soluble proteins 
(including cytokines, chemokines, 
and inflammatory markers)
Antivector immune responses
Autoantibodies: ANA, anti-SMA, 
AMA, and anti-TPO
ALP = alkaline phosphatase; ALT = alanine aminotransferase; AMA = antimitochondrial antibody; ANA = antinuclear antibody; 
aPTT = activated partial thromboplastin time; AST = aspartate aminotransferase; BUN = blood urea nitrogen; CBC = complete 
blood count; CK = creatine kinase; CPK = creatine phosphokinase; DNA = deoxyribonucleic acid; ELISpot = enzyme-linked 
immunospot assay; FSH = follicle-stimulating hormone; GGT = gamma-glutamyl transferase; HBV = hepatitis B virus; 
HBeAb = hepatitis B e antibody; HBeAg = hepatitis B e antigen; HCV = hepatitis C virus; HDV = hepatitis D virus; 
HIV = human immunodeficiency virus; IFN = interferon; INR = international normalized ratio; RNA = ribonucleic acid; 
SMA = smooth muscle antibody; TPO = thyroid peroxidase 
Refer to Table 1, Table 2, and Table 3 for collection time points.

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6.4.5.1.
Blood Sampling
Blood samples will be collected for the following laboratory analyses:
•
Hematology: Hematocrit, hemoglobin, platelet count, red blood cell count, white blood cell 
count with differential (absolute and percentage), including lymphocytes, monocytes, 
neutrophils, eosinophils, basophils, and mean corpuscular volume 
•
Coagulation panel: prothrombin time, activated partial thromboplastin time, and INR 
•
Chemistry (fasting at screening only; otherwise nonfasting): ALP, AST, ALT, 
gamma-glutamyl transferase (GGT), total bilirubin, direct and indirect bilirubin, total 
cholesterol, high-density lipoprotein, low-density lipoprotein, triglycerides, total protein, 
albumin, lactate dehydrogenase, creatine phosphokinase/CK, bicarbonate, blood urea 
nitrogen, calcium, chloride, creatinine, glucose, hemoglobin A1c, phosphorus, magnesium, 
potassium, sodium, uric acid, and lipase. 
•
Serum pregnancy test for all women of childbearing potential (Note: 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)
•
Follicle-stimulating hormone testing (screening only) for participants assigned female at birth 
who are younger than 54 years, not on hormonal contraception, and who have stopped 
menstruating for at least 12 months but do not have documentation of ovarian hormonal 
failure
•
HIV-1, HBV, and HCV testing
•
HDV testing (Phase 1b only)
6.4.5.2.
Urine Samples
Urine samples will be collected for urinalysis and alcohol and drug screen assessments, which 
may include alcohol, amphetamines, barbiturates, benzodiazepines, cocaine, marijuana, 
3,4-methylenedioxymethamphetamine, methadone, opiates, and phencyclidine at screening and 
Day 1. 
6.4.5.3.
Pregnancy Testing
Serum pregnancy testing will be performed at screening and baseline (Day 1). On all dosing 
days, urine pregnancy testing will be performed in addition to serum testing to confirm 
pregnancy status for all women of childbearing potential. Pregnancy testing will continue every 
28 days posttreatment as shown in Table 1, Table 2, and Table 3 until the end of study follow-up. 

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For Cohorts 1 to 2, safety follow-up Day 113, Day 169, and Day 197; for Cohorts 3 to 6, safety 
follow-up Day 141, Day 197, and Day 225; and for Cohorts 7 to 8, safety follow-up Day 169, 
Day 197, Day 225, Day 253, Day 281, and Day 309 are required only for pregnancy testing for 
women of childbearing potential. These participants will come to the site and undergo serum 
pregnancy testing, with the exception of participants who are able to access an at-home urine 
pregnancy test from the clinical site; these participants may conduct their pregnancy test at home 
and will be contacted by site staff to confirm the result.
6.4.6.
Creatinine Clearance
Weight will be collected at screening to calculate CLcr for inclusion criteria. For all other CLcr 
calculations, the most current recorded weight will be used.
6.4.7.
Concomitant Medications/Protocol Restrictions
Review of concomitant medications, and review of protocol restrictions will occur at the times 
shown in Table 1, Table 2, and Table 3. See Sections 4.2.2, 4.3.2, and 5.6 for more information 
about concomitant medications.
6.5.
Posttreatment Assessments
The last investigational product administered will be Day 57 for participants in Cohorts 1 and 2, 
Day 85 for participants in Cohorts 3, 4, 5, and 6, and Day 141 for Cohorts 7 and 8. Safety and 
biomarker analyses follow-up visits are planned for all participants. Study procedures and 
assessments are outlined in Table 1, Table 2, and Table 3.
6.6.
Assessments for Early Discontinuation From Investigational Product or 
From the Study
If a participant discontinues dosing with the investigational product (see Section 3.3), for 
example as a result of an AE, the ET visit evaluation and/or procedures outlined in Table 1, 
Table 2, and Table 3 should be performed within 7 days of last investigational product dose. If 
the last investigational product dose was received more than 7 days prior to decision to 
discontinue future dosing, the ET visit should be completed at the next scheduled study visit. 
Every attempt should be made to keep the participant on the study and continue to perform 
study-related follow-up and procedures. Evaluations indicating abnormal results believed to be 
related to investigational product at the ET visit should be repeated weekly or as often as deemed 
appropriate by the investigator until the abnormality resolves, returns to baseline visit levels, or 
is otherwise explained.
If a participant withdraws consent from the study, the ET visit will be their last study visit.
6.6.1.
Assessments for End of Study
A participant who completes the study will have an end of study visit for assessments and 
procedures specified in Table 1, Table 2, and Table 3. 

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Sample Storage 
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Stored biological samples may be used by Gilead or its research partner for future testing to 
provide additional data to answer questions that relate to the main study. At the end of this study, 
these samples ma be retained in stora e b Gilead for u to 20 ears or er countr 
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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 an 
investigational product that does not necessarily have a causal relationship with that 
investigational product. An AE can, therefore, be any unfavorable and/or unintended sign, 
symptom, or disease temporally associated with the use of an investigational product, whether or 
not considered related to the investigational product. 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, and 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 (see 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 medical history.
Preexisting events that increase in severity or change in nature after investigational product 
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.)

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•
Inpatient hospitalization or prolongation of existing hospitalization.
•
Persistent or significant disability/incapacity.
•
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 a 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.
Investigational Products and Gilead Concomitant Therapy Special Situation 
Reports
Special situations reports (SSRs) 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 an investigational product while the medication is in the 
control of a health care professional, patient, 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 an investigational product 
by a participant.
Misuse is defined as any intentional and inappropriate use of an investigational product 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 an 
investigational product 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 an investigational product as a result of one’s 
professional or nonprofessional occupation.

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Drug interaction is defined as any drug/drug, drug/food, drug/alcohol, or drug/device interaction. 
Unexpected benefit is defined as an unintended therapeutic effect where the results are judged to 
be desirable and beneficial. 
Transmission of infectious agents is defined as any suspected transmission of an infected agent 
through a Gilead investigational product.
Counterfeit or falsified medicine is defined as any investigational product 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 Investigational Products and Procedures
The investigator or qualified subinvestigator is responsible for assessing the relationship for each 
investigational product using clinical judgment and the following considerations:
•
No: Evidence exists that the AE has an etiology other than the investigational product. 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 investigational 
product.
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 Common Terminology Criteria for Adverse Events 
(CTCAE), Version 5.0. For each episode, the highest grade attained should be reported as 
defined in the toxicity grading scale (Appendix 11.6).

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7.3.
Investigator Reporting Requirements and Instructions 
7.3.1.
Requirements for Collection Prior to Investigational Product Initiation
After informed consent, but prior to initiation of the investigational product, the following types 
of events must be reported on the applicable eCRFs: all SAEs and any AEs related to 
protocol-mandated procedures.
7.3.2.
Adverse Events
Following initiation of study treatment, collect all AEs, regardless of cause or relationship, until 
the end of study follow-up (24 weeks) after last administration of investigational product and 
report the AEs on the eCRF 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 occurs after the participant first consents to 
participate in the study (ie, signing the informed consent) and throughout the duration of the 
study, including the posttreatment follow-up visit, must be reported on the applicable eCRFs and 
PS as instructed below in this section. This also includes any SAEs resulting from 
protocol-associated procedures performed after informed consent is signed.
Any SAEs and deaths that occur after the posttreatment follow-up visit but within 24 weeks of 
the last dose of investigational product, regardless of causality, should also be reported. 
Investigators are not obligated to actively seek SAEs after the protocol-defined follow-up period; 
however, if an 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 the investigational product, 
the investigator should promptly document and report the event to PS.
Instructions for reporting SAEs are described in Section 7.4.1.
7.3.4.
Investigational Product Special Situations Reports
All investigational product SSRs that occur from investigational product initiation and 
throughout the duration of the study, including the posttreatment follow-up visit, must be 
reported to PS (Section 7.4.2). Adverse events and SAEs resulting from SSRs must be reported 
in accordance to the AE and SAE reporting guidance (Section 7.4).

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7.3.5.
Concomitant Therapy Reports
7.3.5.1.
Gilead Concomitant Therapy Special Situations Report
Special situations reports involving a Gilead concomitant therapy (not considered investigational 
product), that occurs after the participant first consents to participate in the study (ie, signing the 
informed consent) and throughout the duration of the study, including the posttreatment 
follow-up visit, must be reported to PS utilizing the paper SSR (Section 7.4.2.2).
7.3.5.2.
Non-Gilead Concomitant Therapy 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 due to a non-Gilead concomitant 
medication, the AE should be reported on the AE form. 
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 report form. 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 PS within 24 hours of the investigator’s knowledge of the event from ICF 
signature throughout the duration of the study, including the protocol-required posttreatment 
follow-up period. 
If it is not possible to record and transmit the SAE information electronically, record the SAE on 
the paper SAE reporting form and transmit the report within 24 hours:

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Patient Safety 
Email: Safety_FC@gilead.com 
or
Fax: +1-650-522-5477
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 PS.
7.4.2.
Special Situations Reporting Process 
7.4.2.1.
Electronic Special Situations Reporting Process for Investigational Product 
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 PS from investigational product 
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 the SSR information electronically, record the SSR 
on the paper SSR form and transmit the report to:
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 PS. 
See Section 7.1.3 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 
investigational product must be reported within 24 hours of the investigator’s knowledge of the 
event to PS utilizing the paper SSR form to:
Patient Safety
Email: Safety_FC@gilead.com 
or
Fax: +1-650-522-5477

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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 due to a non-Gilead concomitant 
medication, must be reported as an AE.
7.4.2.3.
Pregnancy Reporting Process
The investigator should report pregnancies in female study participants and/or female partners of 
male participants that are identified after initiation of investigational product and throughout the 
study, including the protocol-required posttreatment follow-up period in participants and/or 
pregnancies in partners resulting from exposure to sperm from a participant in the study period in 
which contraceptive measures are needed. Pregnancies should be reported to PS using the paper 
pregnancy report form within 24 hours of becoming aware of the pregnancy. 
Contact details for transmitting the pregnancy report form are as follows:
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 due to 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 poststudy must 
be reported to PS; however, if the SAE occurs in a partner, the pregnancy-related SAE will not 
be captured in eCRF but should be reported via the paper pregnancy outcome report form.
The participant should receive appropriate monitoring and care until the conclusion of the 
pregnancy. The outcome of the pregnancy/partner pregnancy should be reported to PS using the 
pregnancy outcome report form. If the end of the pregnancy/partner pregnancy occurs after the 
study has been completed, the outcome should be reported directly to PS. Patient Safety contact 
information is as follows: 
Patient Safety 
Email: Safety_FC@gilead.com 
or
Fax: +1-650-522-5477

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Refer to Appendix 11.4 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 United States 
(US) FDA CFR, the European Union Clinical Trials Directive (2001/20/EC)/EU Regulation 
536/2014 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 SUSARs. In accordance with the 
European Union Clinical Trials Directive (2001/20/EC)/EU Regulation 536/2014, Gilead or a 
specified designee will notify worldwide regulatory agencies and the relevant IEC in concerned 
member states of applicable SUSARs as outlined in current regulations.
The investigator should notify the IEC of SUSAR reports as soon as is practical, where this is 
required by local regulatory agencies, and in accordance with the local institutional policy. 
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 investigational product 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, respectively. 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 CTCAE, Version 5.0 (Section 7.2.2). 
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.
7.7.
Toxicity Management
All treatment-emergent toxicities will be noted by the investigator and brought to the attention of 
the Gilead 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 Gilead medical monitor.

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All clinical and clinically significant laboratory toxicities will be managed according to uniform 
guidelines detailed in Appendix11.5, 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. The investigational product may be continued without dose interruption for a 
clinically insignificant Grade 3 and 4 laboratory abnormality (eg, CK elevation after 
strenuous exercise, triglyceride elevation that is nonfasting or that can be medically 
managed). Recurrence of laboratory abnormalities considered unrelated to the investigational 
product may not require permanent discontinuation.
•
Grade 3 or 4 clinical events, if considered unrelated to the investigational product, may not 
require dose interruption and continuation of the investigational product is at the discretion of 
the investigator.
The Gilead medical monitor should be consulted prior to investigational product discontinuation 
when medically feasible.
7.7.1.
Grades 1 and 2 Laboratory Abnormality or Clinical Event
•
For a Grade 1 or 2 clinical event or clinically significant laboratory abnormality, continue the 
investigational product at the discretion of the investigator.
7.7.2.
Grades 3 Laboratory Abnormality or Clinical Event
•
For a Grade 3 clinical event or clinically significant laboratory abnormality confirmed by 
repeat testing that is considered to be related to the investigational product (with the 
exception of ALT and AST elevations), the investigational product should be withheld until 
the toxicity returns to Grade 2 or below. 
•
If a laboratory abnormality recurs to Grade 3 or higher following rechallenge with the 
investigational product and this is considered related to the investigational product, then the 
investigational product should be permanently discontinued, and the participant managed 
according to local standard of care. Recurrence of laboratory abnormalities considered 
unrelated to the investigational product may not require permanent discontinuation.
•
Detailed information on ALT elevation and flare management is provided in Section 7.7.4.
7.7.3.
Grades 4 Laboratory Abnormality or Clinical Event
•
For a Grade 4 clinical event or clinically significant laboratory abnormality confirmed by 
repeat testing considered to be related to the investigational product, investigational product 
should be permanently discontinued, and the participant managed according to local practice. 
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.
•
Detailed information on ALT elevation and flare management is provided in Section 7.7.4.

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7.7.4.
Management of ALT Elevation or Flare
For Cohorts 1 to 4 and 8
Participants with a serum ALT and/or AST > 5  ULN, or ALT > 3  ULN and total bilirubin 
> 2  ULN with or without associated symptoms should be managed according to the guidance 
below. 
Study dosing in an individual participant will be placed on hold and serum ALT or AST meeting 
the criteria above should be confirmed as soon as possible and ideally within 3 days of receipt of 
results. A clinical assessment should be performed and should include a history of recent travel 
and exposures, alcohol consumption, and strenuous exercise. The assessment should also include 
a physical examination, evaluation of the participant’s mental status, and the following 
laboratory tests:
•
Serum ALT and AST, total and direct bilirubin, GGT, INR, serum albumin, alcohol 
screening and urine drug screen
•
If the ALT elevation is confirmed, the central clinical laboratory will conduct reflex testing 
for HIV, plasma HBV DNA, serology for HBV (HBsAg, hepatitis B surface antibody 
[HBsAb], HBeAg, and hepatitis B e antibody [HBeAb]), anti-HDV immunoglobulin (Ig)M 
and HDV RNA, hepatitis A virus (HAV) IgM, HCV antibody, HCV RNA, and hepatitis E 
virus (HEV) IgM 
Participants should be monitored weekly or more frequently if clinically indicated until their 
ALT < 5  ULN. They should then be monitored every 2 weeks until values return to normal. 
Investigational product may be restarted based on the recommendations of the SRT or if a 
self-limited nondrug etiology is identified.
For those with suspected drug-induced liver injury based on Hy’s law (ALT or AST > 3  ULN 
and total bilirubin > 2  ULN), liver biopsy may be performed. 
For Cohorts 5 to 7
Participants with a serum ALT and/or AST > 5  ULN, or ALT > 3  ULN and total bilirubin 
> 2  ULN with or without associated symptoms should be managed according to the guidance 
below. 
All on-treatment elevated serum ALT assessments should be confirmed as soon as possible and 
ideally within 3 days of receipt of results. During the visit, a clinical assessment of the 
participant should be performed. The assessment should include a physical examination, 
evaluation of the participant's mental status, and the following laboratory tests:
•
Serum ALT and AST, ALP, total and direct bilirubin, GGT, INR, serum albumin, complete 
blood count, and urine drug screen

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•
If the ALT elevation is confirmed, the central clinical laboratory will conduct reflex testing 
for HIV, HBV DNA, qualitative HBV serology (HBeAg and HBeAb; HBsAg and HBsAb), 
HAV IgM, HCV RNA, anti-HDV IgM, HDV RNA, HEV IgM, antinuclear antibody, 
antimitochondrial antibody, smooth muscle antibody, and liver/kidney microsome
Based on the results of the confirmatory tests, the following study treatment modifications are 
recommended. 
Table 11.
ALT Elevation Monitoring and Toxicity Management
Liver Toxicity Criteria
Action
Confirmed, ALT and or AST ≥ 10  ULN without 
evidence of hepatic toxicity as defined below
Cohort 5 to 7: Stop investigational product. Evaluate 
adherence to NA therapy and review recent HBV DNA 
results. Evaluate for other causes of hepatoxicity. 
Participant must be monitored weekly or more 
frequently if clinically indicated until ALT returns to 
nadir. Investigative product may be restarted when 
ALT < 5  ULN upon discussion with medical 
monitor. Dosing may also be reinitiated upon the 
recommendations of the SRT.
Persistent ALT and or AST > 2 × baseline and 
≥ 5 × ULN without evidence of hepatic toxicity, as 
defined below
Cohorts 5 to 7: Continue investigative product. ALT 
should be evaluated every 2 weeks or more frequently 
as clinically needed, until values return to nadir. 
Confirmed ALT and or AST > 2 × nadir, with evidence 
of hepatic toxicity, defined as any one of the following 
confirmed laboratory abnormalities:
Total bilirubin > 2 × baseline or nadir AND 
> 2.5 mg/dL in the absence of Gilbert’s disease
Elevated INR > 0.5 above baseline AND > ULN
Abnormal serum albumin > 1 g/dL decrease from 
baseline
Cohorts 5 to 7: Permanently discontinue 
investigational product. Evaluate adherence to NA 
therapy and review recent HBV DNA results. Evaluate 
for etiology of ALT elevation. Participant should be 
monitored weekly until ALT < 5 × ULN, and total 
bilirubin, INR, and albumin values return to normal or 
baseline levels. Liver biopsy may be performed based 
on investigator’s clinical judgment to determine 
etiology.
ALT = alanine aminotransferase; AST = aspartate aminotransferase; DNA = deoxyribonucleic acid; HBV = hepatitis B virus; 
INR = international normalized ratio; NA = nucleos(t)ide analogue; SRT = Safety Review Team; TAF = tenofovir alafenamide; 
ULN = upper limit of normal
7.7.5.
Potential Immune-mediated Adverse Events on Study 
Potential immune-mediated conditions (PIMMC) are AEs that include autoimmune diseases and 
other inflammatory and/or neurologic disorders of interest, which may or may not have an 
autoimmune etiology. PIMMCs have been reported in some vaccine studies and in the clinical 
use of some vaccines {Tavares Da Silva 2013}. For this study, any new onset or worsening of a 
preexisting PIMMC will need to be reported regardless of grade. A list of PIMMC is provided in 
Appendix 11.7. 

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8.
STATISTICAL CONSIDERATIONS
Details of the statistical methods will be provided in the statistical analysis plan and the 
biomarker 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 
Prior to the final analysis, interim analyses may be conducted at the discretion of the sponsor and 
the results from these analyses may be submitted to regulatory agencies to facilitate the overall 
clinical program development or to scientific meetings or journals to disseminate the findings.
8.2.1.1.
Dose-escalation Analysis
For the purpose of making the decision to escalate from the low- to high-dose level or to increase 
the number of doses (at the high dose) from 2 doses of each investigational product, to 3 doses of 
each investigational product (see Section 3.1), interim analyses of relevant safety data will be 
conducted by Gilead. Safety assessments (eg, AEs, ECG, laboratory test results) will be 
displayed by cohort to facilitate these decisions while preserving the blind at the participant 
level.
Review of relevant safety data will be conducted by the SRT to facilitate the decision to escalate 
from the low to high dose; and to increase from 2 doses of each investigational product to 
3 doses of each investigational product (high-dose level).
8.2.2.
Final Analysis
The unblinded final analysis will be performed after all participants have completed the study, 
outstanding data queries have been resolved or adjudicated as unresolvable, and the data have 
been cleaned and finalized. The analysis of the primary endpoints will be conducted at the time 
of the final analysis. 
8.3.
Analysis Conventions
8.3.1.
Analysis Sets
8.3.1.1.
All Randomized Analysis Set
The All Randomized Analysis Set will include all participants randomized into the study after 
screening. This is the primary analysis set for safety listings.

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8.3.1.2.
Safety
The Safety Analysis Set will include all randomized participants who received at least 1 dose of 
investigational product. Participants who received treatment other than that to which they were 
assigned will be analyzed according to the treatment received.
The Safety Analysis Set is the primary analysis set for safety analyses. All data collected during 
the study will be included in the safety summaries.
8.3.1.3.
Pharmacodynamics (Immunogenicity) 
The Immunogenicity Analysis Set will include all randomized participants who received at least 
1 dose of investigational product and have at least 1 nonmissing value for immunogenicity 
evaluation after administration of the investigational product. 
8.3.2.
Data Handling Conventions
Laboratory data that are continuous in nature but are less than the LLOQ or above the 
upper limit of quantification will be imputed to the value of the lower or upper limit minus or 
plus 1 significant digit, respectively (eg, if the result of a continuous laboratory test is less 
than 20, a value of 19 will be assigned; if the result of a continuous laboratory test is less 
than 20.0, a value of 19.9 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 Data and Baseline Characteristics Analysis
Demographic and baseline measurements will be summarized, and descriptive statistics will be 
provided. Demographic summaries will include sex, race, ethnicity, and age at baseline. 
Baseline data will include a summary of body weight, height, BMI, and HBV genotype 
(for Phase 1b participants only). Additional baseline characteristics may be added, as applicable.
8.5.
Safety Analysis
All safety data collected on or after the date that investigational product was first administered 
up to study completion will be summarized by population and treatment group according to the 
investigational product received. Data for the pretreatment period and up to study completion 
will be included in data listings. 
8.5.1.
Extent of Exposure
A participant’s extent of exposure to investigational product data will be generated from the 
investigational product administration data. Exposure data will be listed.

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8.5.2.
Adverse Events
The analysis of data on safety and reactogenicity events will be based on the Safety Analysis Set. 
Data from participants receiving PBO in different cohorts may be combined within the same 
population for the final analysis.
Clinical and laboratory AEs will be coded using the current version of the MedDRA. 
System organ class, high-level group term, high-level term, 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. A treatment-emergent 
AE will be defined as: 
•
Any AE that begins on or after the date of first dose of investigational product and through 
the duration of the study; or any AE leading to investigational product discontinuation.
Summaries (number and percentage of participants) of treatment-emergent AEs (by system 
organ class, high-level term, if applicable, and PT) will be provided by population and treatment 
group using the current version of MedDRA.
•
All TEAEs
•
TEAEs of Grade 3 or higher
•
TEAEs of Grade 2 or higher
•
All treatment-related TEAEs
•
Treatment-related TEAEs of Grade 3 or higher
•
Treatment-related TEAEs of Grade 2 or higher
•
All treatment-emergent SAEs
•
All treatment-related treatment-emergent SAEs
•
All TEAEs leading to premature discontinuation of any investigational product
•
All TEAEs leading to temporary interruption of any investigational product
All AEs collected during the study will be presented in the data listings.
8.5.3.
Laboratory Evaluations
Selected laboratory test data will be summarized using only observed data. Change from baseline 
at all scheduled time points will be summarized. Graded laboratory abnormalities will be defined 
using the grading scheme in Section 11.6. 

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The incidence of treatment-emergent laboratory abnormalities, defined as values that increase by 
at least 1 toxicity grade from baseline levels at any time after baseline evaluation through the 
duration of the study, will be summarized by population and treatment group.
Laboratory abnormalities that occur before the first dose of investigational product will be 
included in a data listing.
8.5.4.
Other Safety Evaluations
Vital signs and ECG data will be summarized by population, treatment group, and visit.
8.6.
Pharmacodynamic Biomarker Analysis (Immunogenicity)
The pharmacodynamic biomarker (immunogenicity) analysis will be based on the proportion of 
participants with investigational product-induced HBV-specific T-cell response, as determined 
by the IFN-γ ELISpot assay, and will be summarized by population and treatment group.
The magnitude of the total investigational product-induced HBV-specific T-cell response, as 
determined by the IFN-γ ELISpot assay, will be summarized by population and treatment group.
The immunoassay result listing will also be included. 
8.7.
Other Exploratory Biomarker Analyses 
Biomarker analyses may include additional measurements of HBV-specific immune response 
including intracellular cytokine staining, anti-HBsAg antibodies, anti-HBsAg immune 
complexes, HBV-specific B-cells, and antivector neutralizing antibodies. Further analyses may 
include gene expression profiling, serum cytokine analysis, T-cell receptor repertoire 
sequencing, peripheral blood mononuclear cell (PBMC) single cell RNA sequencing, and PBMC 
cytometry by time of flight immune phenotyping. Data for each assay performed will be 
summarized by population and/or treatment group and postvaccination changes at defined time 
points calculated against the baseline. The details for the exploratory biomarker analyses will be 
described in a separate biomarker analysis plan.
8.8.
Sample Size
The sample size in this study is determined based on practical considerations and empirical 
experience with similar types of studies. No formal power and sample size calculation was 
performed. Overall, a total sample size of approximately 80 participants (10 participants 
per cohort, (including 8 active and 2 PBO) is expected to provide a suitable assessment of the 
safety, tolerability, and immunogenicity of treatment with the investigational product.

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9.1. 
9.1.1. 
RESPONSIBILITIES 
Investigator Responsibilities 
Good Clinical Practice 
Final 
Amendment2 
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 an angements with the sponsor or proprietaiy interests in the investigational 
product. This documentation must be provided prior to the investigator's (and any 
subinvestigator's) paiiicipation in the study. The investigator and subinvestigator agree to notify 
Gilead of any change in repo1iable interests during the study and for 1 year following completion 
of the study. Study completion is defined as the date when the last paiiicipant completes the 
protocol-defined activities. 
9.1.3. 
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 pa1iicipant (such as 
adve1iisements, paiiicipant infonnation sheets, or descriptions of the study used to obtain 
info1med consent) to an IEC. The investigator will not begin any study paiiicipant activities until 
approval from the IEC has been documented and provided as a letter to the investigator. 
Before implementation, the investigator will submit to and receive documented approval from 
the IEC for any modifications made to the protocol or any accompanying material to be provided 
to the paiiicipant after initial IEC approval, with the exception of those necessa1y to reduce 
immediate risk to study paiiicipants. 
9.1.4. 
Informed Consent 
The investigator is responsible for obtaining written infonned consent from each individual 
paiiicipating in this study after adequate explanation of the aims, methods, objectives, and 
potential hazai·ds of the study before unde1iaking any study-related procedures. The investigator 
must use the most cunent !EC-approved ICF for documenting written info1med consent. Each 
ICF will be appropriately signed and dated by the paiiicipant, the person conducting the consent 
discussion, and also by an impaiiial witness if required by the IEC or local requirements. 
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9.1.5. 
Confidentiality 
Final 
Amendment2 
The investigator must ensure that paiiicipants' anonymity will be strictly maintained and that 
their identities ai·e 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, IEC, or the laborato1y. Laborato1y specimens must be 
labeled in such a way as to protect paiiicipant identity while allowing the results to be recorded 
to the proper paiticipant. Refer to specific laborato1y instructions or in accordance with local 
regulations. NOTE: The investigator must keep a screening log with details for all paiiicipants 
screened and enrolled in the study. 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, investigational product infonnation, and any other study infonnation, 
remain the sole and exclusive prope1iy of Gilead during the conduct of the study and thereafter. 
This infonnation 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) paiiicipant clinical source documents. 
The investigator's study file will contain the protocol/amendments, eCRFs, IEC, and 
governmental approval with con espondence, ICF, diu g records, staff cuniculum vitae and 
authorization fo1ms, and other appropriate documents and conespondence. 
The required source data should include sequential notes containing at least the following 
info1mation for each paiiicipant: 
• 
Paiiicipant identification (name, date of bi1i h, gender) 
• 
Documentation that paiiicipant meets eligibility criteria, ie, histo1y , physical exainination, 
and confnmation of diagnosis (to support inclusion and exclusion criteria) 
• 
Documentation of the reason(s) a consented paiiicipant is not enrolled 
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•
Participation in study (including study number)
•
Study discussed and date of informed consent
•
Dates of all visits
•
Documentation that protocol-specific procedures were performed
•
Start and end dates (including dose regimen) of investigational product, 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 (including start and end dates, dose if relevant, and 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, 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.
If the investigator cannot provide for this archiving requirement at the study 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 Case Report Form Completion Guidelines provided by the sponsor. 
Subsequent to data entry, a study monitor may perform source data verification. 

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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 IECs, 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.
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 IECs in 
accordance with local requirements and receive documented IEC approval before modifications 
may be implemented.
9.2.2.
Study Reports and Publications
A clinical study report will be prepared and provided to the regulatory agency(ies) when 
applicable. 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. 
Results will be submitted within 1 year (6 months for pediatric studies) of the global last 
participant last visit date. 

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Investigators in this study may communicate, orally present, or publish in scientific journals or 
other scholarly media only after the following conditions have been met:
•
The results of the study in their entirety have been publicly disclosed by or with the consent 
of Gilead in an abstract, manuscript, or presentation form or the study has been completed at 
all study sites for at least 2 years.
•
The investigator will submit to Gilead any proposed publication or presentation along with 
the respective scientific journal or presentation forum at least 30 days before submission of 
the publication or presentation. 
•
No such communication, presentation, or publication will include Gilead’s confidential 
information (see Section 9.1.5).
•
The investigator will comply with Gilead’s request to delete references to its confidential 
information (other than the study results) in any paper or presentation and agrees to withhold 
publication or presentation for an additional 60 days in order to obtain patent protection if 
deemed necessary.
9.3.
Joint Investigator/Sponsor Responsibilities
9.3.1.
Payment Reporting
Investigators and their study staff may be asked to provide services performed under this 
protocol (eg, attendance at investigator's 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 accuracy of the data recorded in the eCRFs. The study monitor is responsible 
for routine review of the eCRFs 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.
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.

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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 participants, appropriate regulatory authority(ies), and 
IEC. In terminating the study, Gilead and the investigator will ensure that adequate consideration 
is given to the protection of the participants’ interests.

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10.
REFERENCES
Boni C, Laccabue D, Lampertico P, Giuberti T, Vigano M, Schivazappa S, et al. Restored 
function of HBV-specific T cells after long-term effective therapy with 
nucleos(t)ide analogues. Gastroenterology 2012;143 (4):963-73 e9.
Cargill T, Barnes E. Therapeutic vaccination for treatment of chronic hepatitis B. Clinical and 
experimental immunology 2021;205 (2):106-18.
Chen C, Jiang X, Liu X, Guo L, Wang W, Gu S, et al. Identification of the association between 
HBcAg-specific T cell and viral control in chronic HBV infection using a cultured 
ELISPOT assay. J Leukoc Biol 2020:1-11.
Chu CM, Liaw YF. HBsAg seroclearance in asymptomatic carriers of high endemic areas: 
appreciably high rates during a long-term follow-up. Hepatology 2007;45 
(5):1187-92.
Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron 
1976;16:31-41.
de Niet A, Stelma F, Jansen L, Sinnige MJ, Remmerswaal EB, Takkenberg RB, et al. Restoration 
of T cell function in chronic hepatitis B patients upon treatment with interferon 
based combination therapy. J Hepatol 2016;64 (3):539-46.
Evans T, Bussey L, Teo SL, Tria A, Brown A, Mehta R, et al. Phase 1b/2a study of heterologous 
ChAdOx1-HBV/MVA-HBV therapeutic vaccination (VTP-300) as monotherapy 
and combined with low-dose nivolumab in virally-suppressed patients with CHB 
on nucleos(t)ide analogues [Poster #3328]. International Liver Congress; 2022 
June 22-26; London, UK. 
Fisicaro P, Valdatta C, Massari M, Loggi E, Biasini E, Sacchelli L, et al. Antiviral intrahepatic 
T-cell responses can be restored by blocking programmed death-1 pathway in 
chronic hepatitis B. Gastroenterology 2010;138 (2):682-93, 93 e1-4.
Hoogeveen RC, Dijkstra S, Bartsch LM, Drescher H, Aneja J, Robidoux MP, et al. Hepatitis B 
virus-specific CD4 T-cell responses differentiate functional cure from chronic 
surface antigen(+) infection [Pre-Proof]. J Hepatol 2022.
Hoogeveen RC, Robidoux MP, Schwarz T, Heydmann L, Cheney JA, Kvistad D, et al. 
Phenotype and function of HBV-specific T cells is determined by the targeted 
epitope in addition to the stage of infection. Gut 2019;68 (5):893-904.
Liaw Y-F, Sheen I-S, Chen T-J, Chu C-M, Pao C-C. Incidence, determinants and significance of 
delayed clearance of serum HBsAg in chronic hepatitis B virus infection: a 
prospective study. Hepatology 1991;13 (4):627-31.

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Liaw Y-F, Sung JJY, Chow WC, Farrell G, Lee C-Z, Yuen H, et al. Lamivudine for patients with 
chronic hepatitis B and advanced liver disease. N Engl J Med 2004;351 
(15):1521-31.
Liu Z, Chen O, Wall JBJ, Zheng M, Zhou Y, Wang L, et al. Systematic comparison of 2A 
peptides for cloning multi-genes in a polycistronic vector. Sci Rep 2017;7 
(1):2193.
Maini MK, Pallett LJ. Defective T cell immunity in HBV: why therapeutic vaccination needs a 
helping hand [Preprint]. 2018.
Pallett LJ, Davies J, Colbeck EJ, Robertson F, Hansi N, Easom NJW, et al. IL-2(high) tissue-
resident T cells in the human liver: Sentinels for hepatotropic infection. J Exp 
Med 2017;214 (6):1567-80.
Pattyn J, Hendrickx G, Vorsters A, Van Damme P. Hepatitis B Vaccines. J Infect Dis 2021;224 
(12 Suppl 2):S343-S51.
Ren H, Huang Y. Effects of pegylated interferon-alpha based therapies on functional cure and 
the risk of hepatocellular carcinoma development in patients with chronic 
hepatitis B. J Viral Hepat 2019;26 Suppl 1:5-31.
Roca Suarez AA, Testoni B, Zoulim F. HBV 2021: New therapeutic strategies against an old foe. 
Liver Int 2021;41 Suppl 1:15-23.
Schwendinger M, Thiry G, De Vos B, Leroux-Roels G, Bruhwyler J, Huygens A, et al. A 
Randomized Dose-Escalating Phase I Trial of a Replication-Deficient 
Lymphocytic Choriomeningitis Virus Vector-Based Vaccine Against Human 
Cytomegalovirus. J Infect Dis 2022;225 (8):1399-410.
Singal AG, Lampertico P, Nahon P. Epidemiology and surveillance for hepatocellular 
carcinoma: New trends [Author Manuscript]. J Hepatol 2020;72 (2):250-61.
Stoop JN, van der Molen RG, Kuipers EJ, Kusters JG, Janssen HL. Inhibition of viral replication 
reduces regulatory T cells and enhances the antiviral immune response in chronic 
hepatitis B. Virology 2007;361 (1):141-8.
Tavares Da Silva F, De Keyser F, Lambert PH, Robinson WH, Westhovens R, Sindic C. Optimal 
approaches to data collection and analysis of potential immune mediated disorders 
in clinical trials of new vaccines. Vaccine 2013;31 (14):1870-6.
Thimme R, Wieland S, Steiger C, Ghrayeb J, Reimann KA, Purcell RH, et al. CD8(+) T cells 
mediate viral clearance and disease pathogenesis during acute hepatitis B virus 
infection. J Virol 2003;77 (1):68-76.

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World Health Organization (WHO). Global progress report on HIV, viral hepatitis and sexually 
transmitted infections, 2021. Accountability for the global health sector strategies 
2016–2021: actions for impact. Web Annex 1: Key data at a glance. 2021:
Yip TC, Wong GL, Wong VW, Tse YK, Lui GC, Lam KL, et al. Durability of hepatitis B 
surface antigen seroclearance in untreated and nucleos(t)ide analogue-treated 
patients. J Hepatol 2018;68:63-72.

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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 USA
STUDY ACKNOWLEDGEMENT
A Phase 1a/1b Study to Evaluate the Safety and Tolerability of Repeated Doses of 
Nonreplicating Arenavirus Vector Therapeutic Vaccines GS-2829 and GS-6779 in Healthy 
Participants and Participants With Chronic Hepatitis B (CHB) 
AMENDMENT 2: 20 July 2023
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.
Investigator Name (Printed)
Signature
Date
Site Number

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11.2.
Authorization Status of Study Interventions
Study Intervention 
Name
Category
Authorized in at Least 
1 Country Following EU 
Regulation No. 536/2014
To Be Used per Label 
(Marketed Products Only)
GS-2829
Investigational 
product/vaccine
NA
NA
GS-6779
Investigational 
product/vaccine
NA
NA
Placebo
Reference 
drug/vaccine
NA
NA
Nucleos(t)ide 
analogues (approved 
HBV oral antivirals)
AxMPs
Yes
Yes
AxMPs = auxiliary medicinal products; EU = European Union; HBV = hepatitis B virus; NA = not applicable

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11.3.
Pandemic Risk Assessment and Mitigation Plan
During an ongoing pandemic, 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) Investigational product supplies to participants and sites:
a) Participants may be unable to return to the site for a number of visits to get the 
investigational product, or the site may be unable to accept any participant visits. Without 
investigational products, the participant would not be able to stay on the investigational 
product as planned per protocol.
Mitigation plan: For participants who may be unable to continue the schedule in person, 
at the earliest opportunity, the site will schedule in-person participant visits and return to 
the protocol’s regular schedule of assessments. 
b) Shipments of investigational product could be delayed because of transportation issues. 
Without investigational products, the participant would not be able to continue receiving 
the investigational product as planned per protocol.
Mitigation plan: The site’s investigational product inventory should be closely monitored. 
Site staff should notify the sponsor or delegate if they foresee shortage in investigational 
product inventory or if there is any interruption in local shipping service. The sponsor 
will continue to monitor inventory at the investigational product 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 virtual study visit, via phone or video 
conferencing, to assess the participant within target visit window date whenever possible. 
During the remote study visit, the following information at minimum will be reviewed: 
i)
Confirm if participant has experienced any adverse events (AEs)/serious adverse 
events (SAEs)/special situations (including pregnancy) and follow-up on any 
unresolved AE/SAEs.
ii) Review current list of concomitant medications and document any new concomitant 
medications.
iii) Confirm if participant diary has been completed.

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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 visit per protocol. Any changes in the party conducting laboratory assessments 
for the study due to the pandemic 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 local independent ethics committee (IEC) and national laws and 
regulations. Remote consent will be allowed if has been approved by the local IEC. 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 occur 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 due to the pandemic must be reported in the eCRF and described 
in the clinical study report. Any virtual study visits that are conducted in lieu of clinic 
visits due to the pandemic will be documented as a protocol deviation related to the 
pandemic.
b) Study monitors may be unable to carry out source data review or source data verification 
(SDV), or investigational product accountability or assess protocol and Good Clinical 
Practice compliance. This may lead to delays in SDV, 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 SDV may be arranged if allowed. The 
study monitor is to reference the Study Monitoring Plan (or equivalent plan) for guidance 
on how to conduct a remote 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.

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4) Missing data and data integrity:
a) There may be an increased amount of missing data due to participants missing 
visits/assessments. This could have an impact on the analysis and the interpretation of 
clinical study data. 
Mitigation plan: Implications of a pandemic on methodological aspects for the study will 
be thoroughly assessed and documented, and relevant actions will be taken as appropriate 
(ie, modification of the statistical analysis plan) and in compliance with regulatory 
authorities’ guidance. Overall, the clinical study report will describe the impact of the 
pandemic 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 GS-2829 and GS-6779 in study participants will remain 
unchanged. 

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11.4.
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 Female Participants Assigned Female at Birth and of 
Childbearing Potential
a. Investigational Product Effects on Pregnancy and Hormonal Contraception
GS-2829 and GS-6779 are contraindicated in pregnancy as the effect on fetal development is 
unknown. There are no data on the use of GS-2829 and GS-6779 in pregnant women. 
Nonclinical toxicology studies of GS-2829 and GS-6779 for evaluating genotoxicity, fertility, or 
embryo-fetal development have not been performed. There are no available data to indicate that 
there is no reduction in clinical efficacy of hormonal contraception. Women of childbearing 
potential should use highly effective contraception for at least 6 months following the last dose 
of investigational product. Refer to the latest version of the investigator’s brochure for additional 
information.

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b. 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 the 
use of highly effective contraceptive measures with a failure rate of less than 1% per year. They 
must have a negative serum pregnancy test at screening and a negative pregnancy test before 
vaccination. Pregnancy tests will be performed at monthly intervals thereafter until the end of 
contraception requirement.
Duration of required contraception for participants assigned female at birth and of childbearing 
potential in this clinical study should start from the screening visit until 6 months after the last 
dose of investigational product.
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: 
Nonhormonal intrauterine device (IUD) 
Hormonal IUD (must be used in conjunction with a barrier method)
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 wish to use a 
hormonally based method must use it in conjunction with a barrier method, preferably a male 
condom. Hormonal methods are restricted to those associated with the inhibition of 
ovulation. Hormonally based contraceptives and barrier methods permitted for use in this 
protocol are as follows:
Hormonal methods (each method must be used with a barrier method, preferably male 
condom)
■Oral contraceptives (either combined or progesterone only)
■Injectable progesterone

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■Subdermal contraceptive implant
■Transdermal contraceptive patch
■Contraceptive vaginal ring
Barrier methods (each method must be used with a hormonal method)
■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
It is theoretically possible that a relevant systemic concentration of investigational product may 
be achieved in a partner assigned female at birth from exposure to the participant’s seminal fluid 
and pose a potential risk to an embryo/fetus. A participant assigned male at birth with a partner 
assigned female at birth and of childbearing potential must use condoms during treatment and 
until 6 months after last dose of investigational product. If the partner assigned female at birth 
and of childbearing potential is not pregnant, additional contraception recommendations should 
also be considered.
Participants assigned male at birth must also refrain from sperm donation during treatment and 
until the end of contraception requirement.
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.

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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 to end of study. 
Investigational product must be discontinued immediately.
Participants assigned male at birth whose partner has become pregnant or suspects they are 
pregnant from start of study to 6 months after the last investigational product dose must also 
report the information to the investigator 
Instructions for reporting pregnancy, partner pregnancy, and pregnancy outcome are outlined in 
Section 7.4.2.3.

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11.5.
Management of Clinical and Laboratory Adverse Events
I 
Grade 1 
I I 
Grade 2 
I I 
Grade 3 
I I 
Grade 4 
I 
I I 
1 
I 
I 
Continue study drug dosing at the 
H 
Repeat laboratory or clinical 
If confirmed Grade 4, 
discretion of the investigator 
assessment to confirm toxicity grade 
and related to study 
drug(s), discontinue 
study drug(s) dosing 
permanently, and 
manage participant 
according to local 
If confirmed Grade 3, and related to study drug(s): 
If confirmed and 
practice. Participant 
should be followed as 
unrelated to study 
clinically indicated 
1. Withhold study drug(s) until!, Grade 2 
drug(s), dosing may 
until the laboratory 
2. Restart all study drug(s) at full dose upon discussion with the 
continue at the 
abnormality returns 
Gilead medical monitor 
discretion of the 
to baseline, or is 
investigator. 
otherwise explained. 
' 
' 
If Grade 3 or 4 recurrence is 
If Grade 3 or 4 
confirmed and related to study 
recurrence is confirmed 
drug(s), discontinue all study 
and unrelated to study 
drug(s) permanently, and 
drug(s), continue all 
manage the participant 
study drug(s) at the same 
according to local practice. 
dose at the discretion of 
the investigator. 

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11.6.
Toxicity Grading Scale for Severity of Adverse Events and Laboratory 
Abnormalities
The Common Terminology Criteria for Adverse Events (CTCAE), Version 5.0 
(November 2017) will be used in this study.
https://ctep.cancer.gov/protocoldevelopment/electronic_applications/docs/CTCAE_v5_Quick_R
eference_8.5x11.pdf

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11.7.
Potential Immune-mediated Conditionsa
This list of potential immune-mediated conditions is not to be considered exhaustive, and 
investigators may use clinical judgment in applying this list and may consult the medical monitor 
in situations they believe a new event in a participant may be immune mediated but is not in the 
list below.
Neuroinflammatory disorders
•
Cranial nerve inflammatory disorders, including paralyses/paresis (eg, Bell’s palsy)
•
Optic neuritis
•
Multiple sclerosis
•
Transverse myelitis
•
Acute disseminated encephalomyelitis, including site-specific variants: encephalitis, 
encephalomyelitis, myelitis, myeloradiculoneuritis, cerebellitis
•
Myasthenia gravis (including Lambert-Eaton myasthenic syndrome)
•
Immune-mediated peripheral neuropathies and plexopathies (including Guillain-Barré 
syndrome, Miller Fisher syndrome and other variants, chronic inflammatory demyelinating 
polyneuropathy, multifocal motor neuropathy and polyneuropathies associated with 
monoclonal gammopathy)
•
Narcolepsy
Musculoskeletal disorders
•
Systemic lupus erythematosus
•
Systemic sclerosis (with limited or diffuse cutaneous involvement)
•
Dermatomyositis
•
Polymyositis
•
Antisynthetase syndrome
•
Rheumatoid arthritis
•
Juvenile chronic arthritis (including Still's disease)
•
Polymyalgia rheumatica

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•
Spondyloarthritis, including ankylosing spondylitis, reactive arthritis (Reiter's syndrome) and 
undifferentiated spondyloarthritis
•
Psoriatic arthropathy
•
Relapsing polychondritis
•
Mixed connective tissue disorder
Skin disorders
•
Psoriasis
•
Vitiligo
•
Erythema nodosum
•
Autoimmune bullous skin diseases (including pemphigus, pemphigoid, and dermatitis 
herpetiformis)
•
Cutaneous lupus erythematosus
•
Alopecia areata
•
Lichen planus
•
Sweet's syndrome
•
Morphea
Liver disorders
•
Autoimmune hepatitis
•
Primary biliary cirrhosis
•
Primary sclerosing cholangitis
•
Autoimmune cholangitis

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Gastrointestinal disorders
•
Crohn's disease
•
Ulcerative colitis
•
Ulcerative proctitis
•
Celiac disease
Metabolic and Endocrine disorders
•
Autoimmune thyroiditis (including Hashimoto thyroiditis)
•
Grave's or Basedow's disease
•
Diabetes mellitus type I
•
Addison's disease
Vasculitides
•
Large vessels vasculitis including giant cell arteritis such as Takayasu's arteritis and temporal 
arteritis
•
Medium sized and/or small vessels vasculitis including: polyarteritis nodosa, Kawasaki's 
disease, microscopic polyangiitis, Wegener's granulomatosis, Churg–Strauss syndrome 
(allergic granulomatous angiitis), Buerger's disease (thromboangiitis obliterans), necrotizing 
vasculitis and antineutrophil cytoplasmic antibody positive vasculitis (type unspecified), 
Henoch-Schonlein purpura, Behcet's syndrome, leukocytoclastic vasculitis
Others
•
Autoimmune hemolytic anemia
•
Autoimmune thrombocytopenia
•
Antiphospholipid syndrome
•
Pernicious anemia
•
Autoimmune glomerulonephritis (including immunoglobulin A nephropathy, 
glomerulonephritis rapidly progressive, membranous glomerulonephritis, 
membranoproliferative glomerulonephritis, and mesangioproliferative glomerulonephritis)
•
Uveitis

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•
Autoimmune myocarditis/cardiomyopathy
•
Sarcoidosis
•
Stevens-Johnson syndrome
•
Sjogren's syndrome
•
Idiopathic pulmonary fibrosis
•
Goodpasture syndrome
•
Raynaud's phenomenon
a
Da Silva, Fernanda Tavares, et al. "Optimal approaches to data collection and analysis of potential immune mediated 
disorders in clinical trials of new vaccines." Vaccine 31.14 (2013): 1870-1876.

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11.8.
Country-Specific Requirements
Not applicable.

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11.9.
Amendment History
High-level summaries of the history of this study’s amendments are provided in tabular form in 
the subsections below (from most recent amendment to oldest), with changes listed in each table 
in order of importance. Minor changes such as the correction of typographic errors, grammar, or 
formatting are not detailed.
A separate tracked change (red-lined) document comparing the original protocol to this 
amendment will be made available upon the publication of this protocol.
11.9.1.
Amendment 2 (20 July 2023)
Rationale for Key Changes Included in Amendment 2
Affected Sections
Two cohorts (7 and 8) were added to investigate the addition of a third dose of 
each vaccine. This brings the number of participants for the study to 
approximately 80.
Synopsis, Section 1, 
Section 3, Section 4, 
Section 6, and Section 7 
The previous viremic cohort (Cohort 7 ) was removed from the study and replaced 
with virally suppressed CHB participants in order establish the safety and 
tolerability, and immunogenicity profile of 3 doses in this population. Secondary 
to establishing the safety profile, will inform on the impact of 3 versus 2 doses on 
magnitude and durability of vaccine-elicited immune responses.
Throughout, as needed
The upper limit of the age range for Phase 1b participants was increased from 60 
to 65 years, inclusive, to increase enrollment
Throughout, as needed
An additional Safety Review Team (SRT) review was added to review data prior 
to initiating the third dose of the vaccines
Synopsis, Section 3 
Select biomarker/safety assessments for Phase 1b have been removed from the 
assessments to reduce the blood volume draw
Synopsis, Section 6
Safety language as related to reporting toxicity levels has been updated to indicate 
that participants receiving the same high-dose level (Cohorts 4 and 8 for Phase 1a, 
and Cohorts 6 and 7 for Phase 1b) will be considered cumulative events for 
stopping rules.
Section 3.3.3.1
Clarification of use of systemic antibiotics has been added to the concomitant 
medications.
Section 5.6.1
Minor changes to correct typographic errors and ensure consistency and clarity 
were made.
Throughout, as needed

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11.9.2.
Amendment 1 (23 November 2022)
Rationale for Key Changes Included in Amendment 1
Affected Sections
The number of planned Phase 1b study centers was increased for improved 
enrollment.
Synopsis
Study schemas were updated to include genotyping for Cohorts 5 and 6.
Study Schema
Laboratory requirements were updated, genotyping at screening for Cohorts 5 and 
6 was added, hepatitis D virus testing and autoantibody testing for healthy 
volunteers were removed, and in-clinic postdose monitoring period was extended 
for all participants.
Table of Assessments, 
Section 4, and Section 5
Change was made to align stopping rules to European Medicines Agency 
requirements.
Section 3
Change was made to align early discontinuation rules to United States Food and 
Drug Administration requirements.
Section 3
Inclusion criteria for Cohorts 5 and 6 were updated to aide with enrollment.
Section 4
Inclusion criteria for Cohort 7 were updated to remove “genotype identifiable” 
simplifying the screening process.
Section 4
Change was made to add follow-up telephone calls after each dose of 
investigational product
Figures 2 and 3, Table of 
Assessments, and Section 6
Appendices were added for country-specific requirements and amendment 
history.
Appendices 11.8 and 11.9
Minor changes to correct typographic errors and ensure consistency and clarity 
were made.
Throughout, as needed

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11.10.
Sponsor Signature Page
GILEAD SCIENCES, INC.
333 LAKESIDE DRIVE
FOSTER CITY, CA 94404 USA
A Phase 1a/1b Study to Evaluate the Safety and Tolerability of Repeated Doses of 
Nonreplicating Arenavirus Vector Therapeutic Vaccines GS-2829 and GS-6779 in Healthy 
Participants and Participants With Chronic Hepatitis B (CHB) 
AMENDMENT 2: 20 July 2023
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
Signature
[See appended electronic signature]
Date
PPD-

protocol GS-US-642-5670 amd-2
ELECTRONIC SIGNATURES
Signed by
Meaning of Signature
Server Date
(dd-MMM-
yyyy hh:mm:ss)
Clinical Development
eSigned
20-Jul-2023
16:52:32
PPD-