Open-Label, Global, Multicenter, Randomized, Phase 3 Study of Sacituzumab Govitecan Versus Docetaxel in Patients With Advanced or Metastatic Non-Small Cell Lung Cancer (NSCLC) With Progression on or After Platinum-Based Chemotherapy and Anti-PD-1/PD-L1 Immunotherapy
Phase: PHASE3
Conditions: Non-Small Cell Lung Cancer
Sponsor: Gilead Sciences

CLINICAL STUDY PROTOCOL
Study Title:
Open-Label, Global, Multicenter, Randomized, Phase 3 Study of 
Sacituzumab Govitecan Versus Docetaxel in Patients With 
Advanced or Metastatic Non-Small Cell Lung Cancer (NSCLC) 
With Progression on or After Platinum-Based Chemotherapy and 
Anti-PD-1/PD-L1 Immunotherapy
Sponsor:
Gilead Sciences, Inc.
333 Lakeside Drive
Foster City, CA 94404
USA
IND Number:
156176
EU CT Number:
2021‐003578‐30
ClinicalTrials.gov 
Identifier:
NCT05089734
Indication:
Non-Small Cell Lung Cancer
Protocol ID:
GS-US-577-6153
Contact Information:
The medical monitor name and contact information will be 
provided on the Key Study Team Contact List.
Protocol 
Version/Date:
Original:
11 August 2021
Amendment 1:
15 September 2021
Amendment 2:
22 December 2022
This study will be conducted under United States Food and Drug Administration investigational 
new drug application regulations (21 Code of Federal Regulations Part 312); however, sites 
located in the European Economic Area, the United Kingdom, and Switzerland are not included 
under the investigational new drug application and are considered non-investigational new drug 
application sites.
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The information contained in this document, particularly unpublished data, is the property or 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................................................................................................................................................2
LIST OF APPENDICES.................................................................................................................................................5
LIST OF IN-TEXT TABLES .........................................................................................................................................5
LIST OF IN-TEXT FIGURES........................................................................................................................................5
LIST OF ABBREVIATIONS AND DEFINITION OF TERMS ...................................................................................6
PROTOCOL SYNOPSIS................................................................................................................................................8
STUDY SCHEMA........................................................................................................................................................14
STUDY PROCEDURES TABLE ................................................................................................................................15
1.
INTRODUCTION................................................................................................................................................20
1.1.
Background..............................................................................................................................................20
1.2.
Sacituzumab Govitecan...........................................................................................................................21
1.2.1.
General Information ..............................................................................................................21
1.2.2.
Nonclinical Pharmacology and Toxicology ..........................................................................21
1.2.3.
Clinical Studies of Sacituzumab Govitecan ..........................................................................22
1.3.
Information About Docetaxel..................................................................................................................25
1.3.1.
Description of Docetaxel.......................................................................................................25
1.4.
Rationale for This Study..........................................................................................................................25
1.5.
Rationale for Dose Selection of Sacituzumab Govitecan........................................................................25
1.6.
Rationale for Open-Label Study Design .................................................................................................26
1.7.
Risk/Benefit Assessment for the Study ...................................................................................................26
1.7.1.
Clinical Data for Docetaxel...................................................................................................26
1.8.
Compliance..............................................................................................................................................27
2.
OBJECTIVES AND ENDPOINTS......................................................................................................................28
3.
STUDY DESIGN.................................................................................................................................................30
3.1.
Study Design Overview...........................................................................................................................30
3.2.
Study Treatments.....................................................................................................................................31
3.3.
Duration of Treatment .............................................................................................................................31
3.4.
Discontinuation Criteria ..........................................................................................................................32
3.4.1.
Discontinuation From Study Treatment ................................................................................32
3.4.2.
Discontinuation From the Study............................................................................................32
3.4.3.
Lost to Follow-up ..................................................................................................................33
3.4.4.
Safety and Survival Follow-up..............................................................................................33
3.5.
Definitions for End of Study ...................................................................................................................33
3.6.
Poststudy Care.........................................................................................................................................34
3.7.
Source Data .............................................................................................................................................34
4.
PATIENT POPULATION ...................................................................................................................................35
4.1.
Number of Patients and Patient Selection ...............................................................................................35
4.1.1.
Patient Replacement ..............................................................................................................35
4.2.
Inclusion Criteria.....................................................................................................................................35
4.3.
Exclusion Criteria....................................................................................................................................37
5.
STUDY DRUGS ..................................................................................................................................................39
5.1.
Randomization and Treatment Codes Access .........................................................................................39
5.2.
Description and Handling of Sacituzumab Govitecan ............................................................................39

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5.2.1.
Formulation ...........................................................................................................................39
5.2.2.
Packaging and Labeling ........................................................................................................39
5.2.3.
Storage and Handling ............................................................................................................39
5.3.
Premedication and Prophylaxis for Sacituzumab Govitecan ..................................................................40
5.4.
Dosage and Administration of Sacituzumab Govitecan..........................................................................40
5.5.
Dose Modification and Treatment Delays of Sacituzumab Govitecan ...................................................41
5.5.1.
Dose Reductions and Discontinuation of Sacituzumab Govitecan .......................................42
5.5.2.
Treatment Delays of Sacituzumab Govitecan .......................................................................43
5.6.
Prior and Concomitant Medications With Sacituzumab Govitecan........................................................43
5.6.1.
Prior and Concomitant Medications That are Prohibited or Used With 
Caution With Sacituzumab Govitecan ..................................................................................44
5.7.
Description and Handling of Docetaxel ..................................................................................................44
5.7.1.
Formulation ...........................................................................................................................44
5.7.2.
Packaging and Labeling ........................................................................................................44
5.7.3.
Storage and Handling ............................................................................................................45
5.8.
Premedication and Prophylaxis for Docetaxel ........................................................................................45
5.9.
Dosage and Administration of Docetaxel................................................................................................45
5.10.
Dose Modification and Treatment Delays for Docetaxel........................................................................45
5.11.
Prior and Concomitant Medications With Docetaxel..............................................................................46
5.12.
Accountability for Study Drugs...............................................................................................................46
5.12.1.
Study Drug Return or Disposal .............................................................................................46
6.
STUDY PROCEDURES......................................................................................................................................47
6.1.
Informed Consent ....................................................................................................................................47
6.2.
Screening, Patient Enrollment, and Treatment Assignment....................................................................47
6.3.
Instructions for Study Procedures ...........................................................................................................48
6.3.1.
Adverse Events......................................................................................................................48
6.3.2.
Prior and Concomitant Medications......................................................................................48
6.3.3.
Vital Signs .............................................................................................................................48
6.3.4.
Electrocardiograms................................................................................................................48
6.3.5.
Clinical Laboratory Assessments ..........................................................................................49
6.3.6.
ECOG Performance Status....................................................................................................50
6.3.7.
Efficacy Assessments ............................................................................................................50
6.3.8.
Pharmacokinetics...................................................................................................................51
6.3.9.
Immunogenicity Assessments ...............................................................................................51
6.3.10.
Immunohistology Evaluation of Tumor ................................................................................51
6.3.11.
UGT1A1 Genotype ...............................................................................................................51
6.3.12.
Biomarker Testing.................................................................................................................51
6.3.13.
Quality of Life Assessments..................................................................................................54
6.4.
Assessments for Discontinuation From Study Treatment.......................................................................54
6.5.
Sample Storage........................................................................................................................................54
7.
ADVERSE EVENTS AND TOXICITY MANAGEMENT................................................................................55
7.1.
Definitions of Adverse Events and Serious Adverse Events...................................................................55
7.1.1.
Adverse Events......................................................................................................................55
7.1.2.
Serious Adverse Events.........................................................................................................55
7.1.3.
Study Drugs and Gilead Concomitant Medications Special Situations 
Reports...................................................................................................................................56
7.2.
Assessment of Adverse Events and Serious Adverse Events..................................................................57
7.2.1.
Assessment of Causality for Study Drugs and Procedures ...................................................57
7.2.2.
Assessment of Severity..........................................................................................................58
7.3.
Investigator Reporting Requirements and Instructions ...........................................................................58
7.3.1.
Requirements for Collection Before Study Drug Initiation ..................................................58
7.3.2.
Adverse Events......................................................................................................................58

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7.3.3.
Serious Adverse Events.........................................................................................................58
7.3.4.
Study Drug Special Situations Reports .................................................................................59
7.3.5.
Concomitant Medications Reports ........................................................................................59
7.4.
Reporting Process for Serious Adverse Events and Special Situations Reports.....................................59
7.4.1.
Serious Adverse Event Reporting Process ............................................................................59
7.4.2.
Special Situations Reporting Process ....................................................................................60
7.5.
Gilead Reporting Requirements ..............................................................................................................62
7.6.
Clinical Laboratory Abnormalities and Other Abnormal Assessments as Adverse Events or 
Serious Adverse Events...........................................................................................................................62
7.7.
Toxicity Management..............................................................................................................................63
8.
STATISTICAL CONSIDERATIONS.................................................................................................................64
8.1.
Analysis Objectives and Endpoints.........................................................................................................64
8.2.
Planned Analyses.....................................................................................................................................64
8.2.1.
Interim Analyses....................................................................................................................64
8.2.2.
Final Analysis........................................................................................................................64
8.3.
Analysis Conventions..............................................................................................................................64
8.3.1.
Analysis Sets .........................................................................................................................64
8.3.2.
Data Handling Conventions ..................................................................................................65
8.4.
Demographic and Baseline Characteristics Analysis..............................................................................66
8.5.
Efficacy Analysis.....................................................................................................................................66
8.5.1.
Primary Analysis ...................................................................................................................66
8.5.2.
Secondary Analyses...............................................................................................................66
8.5.3.
Exploratory Analyses ............................................................................................................67
8.6.
Safety Analysis........................................................................................................................................67
8.6.1.
Extent of Exposure ................................................................................................................67
8.6.2.
Adverse Events......................................................................................................................67
8.6.3.
Laboratory Evaluations .........................................................................................................68
8.6.4.
Other Safety Evaluations.......................................................................................................68
8.7.
Adjustments for Multiplicity ...................................................................................................................68
8.8.
Pharmacokinetic Analysis .......................................................................................................................70
8.9.
Immunogenicity Analysis........................................................................................................................70
8.10.
Biomarker Analysis.................................................................................................................................70
8.11.
Sample Size .............................................................................................................................................70
8.12.
Data Monitoring Committee....................................................................................................................71
9.
RESPONSIBILITIES...........................................................................................................................................72
9.1.
Investigator Responsibilities ...................................................................................................................72
9.1.1.
Good Clinical Practice...........................................................................................................72
9.1.2.
Financial Disclosure ..............................................................................................................72
9.1.3.
Institutional Review Board/Independent Ethics Committee Review and 
Approval................................................................................................................................72
9.1.4.
Informed Consent ..................................................................................................................72
9.1.5.
Confidentiality.......................................................................................................................73
9.1.6.
Study Files and Retention of Records ...................................................................................73
9.1.7.
Case Report Forms ................................................................................................................75
9.1.8.
Investigator Inspections.........................................................................................................75
9.1.9.
Protocol Compliance .............................................................................................................75
9.2.
Sponsor Responsibilities .........................................................................................................................75
9.2.1.
Protocol Modifications ..........................................................................................................75
9.2.2.
Study Report and Publications ..............................................................................................76
9.3.
Joint Investigator/Sponsor Responsibilities ............................................................................................76
9.3.1.
Payment Reporting ................................................................................................................76
9.3.2.
Access to Information for Monitoring...................................................................................76

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9.3.3.
Access to Information for Auditing or Inspections ...............................................................76
9.3.4.
Study Discontinuation ...........................................................................................................76
10.
REFERENCES.....................................................................................................................................................77
11.
APPENDICES......................................................................................................................................................80
LIST OF APPENDICES
Appendix 1.
Investigator Signature Page.....................................................................................................81
Appendix 2.
Pandemic Risk Assessment and Mitigation Plan ....................................................................82
Appendix 3.
Pregnancy Precautions, Definition for Female of Childbearing Potential, and 
Contraceptive Requirements....................................................................................................85
Appendix 4.
Toxicity Grading Scale for Severity of Adverse Events and Laboratory 
Abnormalities ..........................................................................................................................89
Appendix 5.
Eastern Cooperative Oncology Group Performance Status Criteria .......................................90
Appendix 6.
Response Evaluation Criteria in Solid Tumors (RECIST Version 1.1) ..................................91
Appendix 7.
UGT1A1 Inhibitors and Inducers............................................................................................94
Appendix 8.
Required Prior Treatment With Targeted Therapy Requirement for Patients With 
Known Actionable Genomic Alterations ................................................................................95
Appendix 9.
Additional Country-Specific Requirements for United Kingdom and European 
Union .......................................................................................................................................96
Appendix 10.
Amendment History ................................................................................................................97
LIST OF IN-TEXT TABLES
Table 1.
GS-US-577-6153: Study Procedures Table.............................................................................15
Table 2.
Guidance for Premedication and Prophylaxis for Toxicities Associated With 
Sacituzumab Govitecan ...........................................................................................................40
Table 3.
Recommended Dose Modification Schedule for Sacituzumab Govitecan..............................42
Table 4.
Laboratory Tests......................................................................................................................49
LIST OF IN-TEXT FIGURES
Figure 1.
GS-US-577-6153 Study Schema.............................................................................................14
Figure 2.
Hierarchical Testing Procedures..............................................................................................69

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LIST OF ABBREVIATIONS AND DEFINITION OF TERMS
ADA
antidrug antibody
ADC
antibody-drug conjugate
AE
adverse event
ALK
anaplastic lymphoma kinase
BRAF
proto-oncogene B-raf
CI
confidence interval
Cmax
maximum observed concentration of drug
CNS
central nervous system
COVID-19
coronavirus disease 2019
CR
complete response
CSR
clinical study report
CT
computed tomography
Ctrough
concentration at the end of the dosing interval
DCR
disease control rate
DMC
data monitoring committee
DOR
duration of response
EC
ethics committee
ECG
electrocardiogram
ECOG
Eastern Cooperative Oncology Group
eCRF
electronic case report form
EDC
electronic data capture
EGFR
epidermal growth factor receptor
EORTC QLQ-C30 v3
European Organisation for Research and Treatment of Cancer Quality of Life 
Questionnaire-Core 30 Version 3
EOT
end of treatment
EQ-5D-3L
EQ-5D-3 level
EU
European Union
FDA
Food and Drug Administration
FDG
fluorodeoxyglucose (18F)
FFPE
formalin-fixed, paraffin-embedded
GCP
Good Clinical Practice
Gilead
Gilead Sciences
HIV
human immunodeficiency virus
HR
hazard ratio
IARC
International Agency for Research on Cancer
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
IRB
institutional review board

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IRT
Interactive Response Technology
ITT
intent to treat
IUD
intrauterine device
IV
intravenous
MRI
magnetic resonance imaging
MTD
maximum tolerated dose
mTNBC
metastatic triple-negative breast cancer
mUC
metastatic urothelial cancer
NCI-CTCAE
National Cancer Institute-Common Terminology Criteria for Adverse Events
NSCLC
non-small cell lung cancer
NSCLC-SAQ
non-small cell lung cancer Symptom Assessment Questionnaire
NTRK
neurotrophic tyrosine receptor kinase
ORR
objective response rate
OS
overall survival
PD
progressive disease
PD-1
programmed death protein 1
PD-L1
programmed death ligand 1
PET
positron emission tomography
PFS
progression-free survival
PGIC
Patient Global Impression of Change
PGIS
Patient Global Impression of Severity
PK
pharmacokinetic(s)
PR
partial response
PRO-CTCAE
Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse 
Events
QOL
quality of life
RECIST
Response Evaluation Criteria in Solid Tumors
ROS1
ROS proto-oncogene 1
SAE
serious adverse event
SAP
statistical analysis plan
SD
stable disease
SG
sacituzumab govitecan
SSR
special situation report
TEAE
treatment-emergent adverse event
TKI
tyrosine kinase inhibitor
Trop-2
trophoblast cell surface antigen-2
UGT1A1
uridine diphosphate glucuronosyltransferase 1A1
ULN
upper limit of normal
US
United States

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PROTOCOL SYNOPSIS
Gilead Sciences, Inc.
333 Lakeside Drive
Foster City, CA 94404
Study Title: Open-Label, Global, Multicenter, Randomized, Phase 3 Study of Sacituzumab 
Govitecan Versus Docetaxel in Patients With Advanced or Metastatic Non-Small Cell Lung 
Cancer (NSCLC) With Progression on or After Platinum-Based Chemotherapy and 
Anti-PD-1/PD-L1 Immunotherapy
IND Number: 156176
EU CT Number: 2021‐003578‐30
ClinicalTrials.gov Identifier: NCT05089734
Study Centers Planned: Approximately 250 centers globally. 
Objectives and Endpoints: 
Primary Objective
Primary Endpoint

To compare the overall survival (OS) of sacituzumab 
govitecan (SG) versus docetaxel.

OS is defined as the time from the date of 
randomization until death due to any cause in the 
Intent-to-Treat (ITT) Analysis Set.
Secondary Objectives
Secondary Endpoints
To compare the effect of SG versus docetaxel on the 
following:

Progression-free survival (PFS) as assessed by the 
investigator per Response Evaluation Criteria in Solid 
Tumors (RECIST) Version 1.1.

PFS is defined as the time from the date of 
randomization until the date of objective disease 
progression or death (whichever comes first) as 
assessed by the investigator per RECIST Version 1.1.

Objective response rate (ORR) as assessed by the 
investigator per RECIST Version 1.1.

ORR is defined as the proportion of patients who 
achieve a complete response (CR) or partial response 
(PR) that is confirmed at least 4 weeks later as 
assessed by the investigator per RECIST Version 1.1.

Duration of response (DOR) as assessed by the 
investigator per RECIST Version 1.1.

DOR is defined as the time from the first 
documentation of CR or PR to the earlier of the 
first documentation of progressive disease (PD) or 
death from any cause (whichever comes first) as 
assessed by the investigator per RECIST Version 1.1.

Disease control rate (DCR) as assessed by the 
investigator per RECIST Version 1.1.

DCR is defined as the proportion of patients who 
achieve a CR, PR, or stable disease (SD) as assessed 
by the investigator per RECIST Version 1.1.

Safety and tolerability.

Incidence of treatment-emergent adverse events 
(TEAEs) and clinical laboratory abnormalities.

Quality of life (QOL) using non–small cell lung cancer 
(NSCLC) Symptom Assessment Questionnaire 
(NSCLC-SAQ).

Time to first deterioration in shortness of breath 
domain as measured by NSCLC-SAQ.

Time to first deterioration in NSCLC-SAQ total score. 

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Exploratory Objectives
Exploratory Endpoints

To characterize the pharmacokinetics (PK) and 
immunogenicity of SG.

Peak (Cmax) and trough (Ctrough) concentrations over 
time and antidrug antibodies (ADAs) over time.

To assess disease-related symptoms and health related 
QOL using EQ-5D-3 level (EQ-5D-3L); 
NSCLC-SAQ; the European Organisation for 
Research and Treatment of Cancer Quality of Life 
Questionnaire-Core 30 Version 3 (EORTC QLQ-C30 
v3); Patient Global Impression of Severity (PGIS); and 
Patient Global Impression of Change (PGIC).

Mean change from baseline of total score and all 
domains of NSCLC--SAQ not assessed as secondary 
endpoints.

Mean change from baseline of all domains of EORTC 
QLQ-C30 v3.

The proportion of patients with meaningful change in 
each QOL domain while on treatment.

Time to first improvement and time to first 
deterioration in each QOL domain not assessed as 
secondary endpoints.

To assess and compare treatment-related symptoms 
using the Patient-Reported Outcomes version of the 
Common Terminology Criteria for Adverse Events 
(PRO-CTCAE).

Frequency, severity, or interference of 
treatment-related symptoms.

To assess tumor expression of trophoblast cell surface 
antigen-2 (Trop-2) as a potential predictive biomarker 
of response to SG.

Correlation of clinical response with baseline tumor 
Trop-2 expression.

To explore blood and tumor biomarkers that may be 
associated with response to SG treatment.

Correlation of clinical response with tumor, tumor 
microenvironment, and blood biomarkers at baseline 
and after SG treatment.

Clearance of circulating tumor DNA upon SG 
treatment.
Study Design: Study GS-US-577-6153 is an open-label, global, multicenter, randomized, 
Phase 3 study to compare the efficacy and safety of SG versus docetaxel in patients with 
advanced or metastatic NSCLC with progression on or after platinum-based chemotherapy and 
anti-programmed death protein 1 (PD-1)/programmed death ligand 1 (PD-L1) immunotherapy 
received either in combination or sequentially. Patients with actionable genomic alterations 
will also be included if they have received prior treatment with an appropriate tyrosine kinase 
inhibitor (TKI). 
Patient participation will include screening, randomization, treatment, and follow-up. 
Screening will last no longer than 28 days to confirm eligibility and establish disease 
characteristics prior to randomization and treatment.
Approximately 580 eligible patients will be randomly assigned in a 1:1 ratio to receive either 
SG (Investigational Arm A) or docetaxel (Control Arm B). Randomization will be stratified 
based on histology (squamous versus nonsquamous), response to last prior immune therapy 
received (best response PD/SD vs CR/PR on immune therapy), and if they have received prior 
therapy for actionable genomic alteration (yes vs no).

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The primary endpoint of the study is OS. Secondary efficacy endpoints are PFS, ORR, DOR, 
and DCR as assessed by the investigator per RECIST Version 1.1; time to first deterioration in 
NSCLC-SAQ total score; and time to first deterioration in shortness of breath as measured by 
NSCLC-SAQ. Safety will be assessed by the reporting of adverse events (AEs), assessments 
of vital signs, laboratory results, and extent of exposure to study drug. Additional QOL 
assessments will be conducted. Pharmacokinetics, ADA, and various biomarkers will also be 
assessed.
Patients will receive study drug until PD, death, unacceptable toxicity, or another treatment 
discontinuation criterion is met. Follow-up will begin at the time of the completion of the end 
of treatment visit, which will occur 30 days (± 7) after the last dose of study drug. All patients 
will be followed for survival until 1 of the discontinuation criteria from the study is met.
An independent data monitoring committee will be convened at regular intervals to assess the 
progress of this study, review safety data, and conduct the interim efficacy analysis.
Following completion of global enrollment, additional patients may be enrolled at sites in 
mainland China in the China Extension Cohort, to ensure adequate number of Chinese 
participants are enrolled to meet local regulatory requirements. Those participants enrolled in 
China after global enrollment is complete will not be a part of the primary analysis for global 
study. The details on China extension cohort is provided in China-specific amendment.
Number of Patients Planned: 
Global Study: Approximately 580 eligible patients will be enrolled.
Target Population: Patients with advanced or metastatic NSCLC with progression on or after 
platinum-based chemotherapy and anti-PD-1/PD-L1 immunotherapy.
Duration of Treatment: Patients will receive study drug until PD, death, unacceptable 
toxicity, or another treatment discontinuation criterion is met.
Treatment with either SG or docetaxel beyond the initial investigator-assessed PD per RECIST 
Version 1.1 is permitted if there is evidence of clinical benefit per the investigator and the 
patient is tolerating study drug. The following clinical criteria should be met for patients to 
continue to receive treatment beyond the investigator-assessed progression: 

Absence of symptoms and signs indicating clinically significant progression of disease

No decline in performance status

Absence of symptomatic rapid disease progression requiring urgent medical intervention 
(eg, symptomatic pleural effusion, spinal cord compression)
Sponsor consultation is required before patients initiate the treatment beyond progression. If 
this occurs, the patient will remain in the study and continue to be monitored according to the 
study procedures table. All patients will be followed for survival until 1 of the discontinuation 
criteria from the study is met 

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Diagnosis and Main Eligibility Criteria: Female or male patients, 18 years of age or older, 
must be able to give signed, written informed consent and comply with protocol requirements. 
Patients must have pathologically documented Stage 4 NSCLC. Patients must have progressed 
after platinum-based chemotherapy in combination with anti-PD-1/PD-L1 antibody OR 
platinum-based chemotherapy and anti-PD-1/PD-L1 antibody (in either order) sequentially. 
No additional treatments are allowed in the recurrent/metastatic setting for patients with no 
actionable genomic alterations. Patients with epidermal growth factor receptor (EGFR), 
anaplastic lymphoma kinase (ALK), or any other known actionable genomic alterations must 
have also received treatment with at least 1 locally approved and available TKI appropriate to 
the genomic alteration. Patients must have documented radiographic disease progression while 
on or after receiving the most recent treatment regimen for advanced or metastatic NSCLC.
Study Procedures/Frequency: The study procedures table and study schema are presented in 
Table 1 and Figure 1, respectively.
Test Product, Dose, and Mode of Administration: Sacituzumab govitecan is administered at 
10 mg/kg via intravenous (IV) infusion on Days 1 and 8 of a 21-day cycle.
Reference Therapy, Dose, and Mode of Administration: Docetaxel is administered at 
75 mg/m2 via IV infusion on Day 1 of a 21-day cycle.
Statistical Methods:
Analysis Sets
The ITT Analysis Set will include all randomized patients according to the treatment arm to 
which the patient is randomized, unless otherwise specified. This is the primary analysis set 
for all efficacy analyses.
The Safety Analysis Set will include all patients who received at least 1 dose of any study 
drug, with treatment assignments designated according to the actual treatment received. This is 
the primary analysis set for all safety analyses.
The PK analysis will be conducted on Pharmacokinetic Analysis Set, defined as all 
randomized patients who received at least 1 dose of SG per the protocol and have at least 
1 measurable posttreatment serum concentration of SG.
The immunogenicity analysis will be conducted on Immunogenicity Analysis Set, defined as 
all randomized patients who received at least 1 dose of SG and have at least 1 evaluable 
posttreatment anti-SG antibody test result.
The biomarker analysis will be conducted on the Biomarker Analysis Set, defined as all 
patients who received any study drug and have at least 1 evaluable posttreatment biomarker 
measurement available.
Quality of life assessments will be analyzed for patients in the ITT Analysis Set.

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Primary Efficacy Analysis
The primary analysis of OS for comparing SG versus docetaxel will be performed in the ITT 
Analysis Set using the log-rank test stratified by randomization stratification factors. The 
hazard ratio (HR) and its 95% CI estimated using a Cox proportional hazard regression model 
stratified by randomization stratification factors will also be presented. Overall survival will be 
summarized by treatment arm using Kaplan-Meier estimates, which will include median and 
the proportion of patients alive at benchmark time points such as 12 and 18 months. 
Kaplan-Meier plots will be provided.
Secondary Efficacy Analyses
At the time of the OS interim analysis, PFS, ORR, and other secondary endpoints will be 
mature for the final analysis, which will be approximately 23 months after the first patient is 
randomized.
The secondary endpoint PFS assessed by the investigator per RECIST Version 1.1 will be 
performed using the same methods as described for the primary OS analysis. Patients who 
have not progressed or died at the time of analysis will be censored according to the censoring 
rules similar to those described in the United States Food and Drug Administration Guidance 
for Industry Clinical Trial Endpoints for the Approval of NSCLC Drugs and Biologics. The 
detailed PFS censoring rules will be described in the statistical analysis plan.
The ORR will be based on RECIST Version 1.1 using investigator-assessed response data. 
The ORR will be analyzed and compared between the treatment arms using the Cochran 
Mantel-Haenszel test stratified by the stratification factors used for randomization. The 2-sided 
95% CIs for each treatment will be calculated using the Clopper-Pearson exact method.
Kaplan-Meier estimates of median DOR and its 95% CI will be calculated for responders 
(CR or PR) in each treatment arm. 
Disease control rate will be analyzed using the same methods as described for ORR.
The NSCLC-SAQ instrument will generate scores for 5 domains and a total score for each 
assessment visit. The analysis of time to first symptom deterioration in NSCLC-SAQ total 
score and time to first deterioration in NSCLC-SAQ shortness of breath domain will be 
conducted between the 2 treatment groups using the log-rank test stratified by randomization 
stratification factors in the ITT Analysis Set. 
Safety Analysis
Safety data will be summarized by treatment arm using descriptive statistics for TEAEs, 
clinical laboratory tests, vital signs, and concomitant medications. Information regarding study 
drug administration, study drug compliance, and other safety variables will also be 
summarized descriptively by treatment arm.

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Pharmacokinetic Analysis
Serum samples for PK analysis will be collected for patients who receive SG. Plasma 
concentrations and PK parameters (ie, Cmax, Ctrough) will be listed and summarized for SG, total 
SN-38, free SN-38, and total antibody using descriptive statistics.
Immunogenicity Analysis
Serum samples for ADA analysis will be collected for patients who receive SG. The impact of 
immunogenicity, if detected, will be evaluated in relation to PK and clinical responses, 
safety/tolerability, and efficacy.
Biomarker Analysis
Baseline Trop-2 analysis will be performed and correlated with clinical outcomes. The 
baseline level, absolute level, and change from baseline level over time will be summarized 
using descriptive statistics for each biomarker at the sample collection time point by treatment 
arm, as appropriate. Exploratory analyses may be performed to evaluate the association of 
each biomarker or combination of biomarkers with clinical outcomes.
Sample Size Calculation
Global Study
Approximately 580 eligible patients will be randomly assigned in a 1:1 ratio to receive either 
SG or docetaxel over a planned nonuniform accrual period of 19 months.
The sample size is estimated based on the primary endpoint of OS. The assumed OS treatment 
effect under the alternative hypothesis is an average HR of 0.70 for SG versus docetaxel, 
which is characterized by a median OS of 11 months on docetaxel treatment and a median OS 
of 15.7 months on SG treatment assuming OS is exponentially distributed. A total of 336 death 
events are required to detect a statistically significant difference at overall 1-sided alpha of 
2.5% with 90% power based on a log-rank test. It is estimated that approximately 580 patients 
will provide 336 death events after approximately 29 months of survival follow-up after the 
first patient is randomized. EAST® 6.5 was used to calculate the sample size.
China Extension Study
Following completion of the global enrollment, additional participants may be enrolled at sites in 
mainland China in the China Extension cohort, to ensure adequate number of Chinese 
participants are enrolled to meet local regulatory requirements. Those participants enrolled in 
China after global enrollment is complete will not be a part of the primary analysis for global 
study. The details on China extension cohort is provided in China-specific amendment. 
This study will be conducted in accordance with the guidelines of Good Clinical Practice, 
including archiving of essential documents.

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STUDY SCHEMA
Figure 1.
GS-US-577-6153 Study Schema
ALK = anaplastic lymphoma kinase; CR = complete response; D = day; DOR = duration of response; DCR = disease control 
rate; EGFR = epidermal growth factor receptor; IO = immuno-oncology; mNSCLC = metastatic non-small cell lung cancer; 
non-sq = non-squamous; ORR = objective response rate; OS = overall survival; PD = progressive disease; PD-L1 = programmed 
death ligand 1, PFS = progression-free survival; PR = partial response; PRO = patient-reported outcomes; q3wk = every 3 weeks; 
SD = stable disease; SOC = standard of care; s/p = status post; sq = squamous; vs = versus
 
 
 
 
 
 
 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
 
 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
  
 
 
 
 
 
 
 
 
 
 
 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 

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STUDY PROCEDURES TABLE
Table 1.
GS-US-577-6153: Study Procedures Table
Phase
Pretreatment
Treatment
Posttreatment
(21-Day Cycles)
Period
Screening
Cycle 1
Cycle 2 Through Last Cycle
End of 
Treatmenta
Follow-up
Day
Days −28
to −1
Day 1
Day 8
Day 1
Day 8
30 Days 
(± 7) After 
Last Dose
Every 
12 Weeks 
From 
EOT Visit 
(± 7)
Notes
Written informed 
consent
X
Demography
X
Medical/surgical history
X
Including prior 
anticancer, 
anticancer surgery, 
and radiation 
therapy
Vital signsb
X
X
X
X
X
X
Blood pressure, 
pulse, respiratory 
rate, and body 
temperature; 
Section 6.3.3
ECOG
X
X
X
X
Complete physical 
examination
X
Clinically-targeted 
physical examination
X
X
X
Height
X

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Phase
Pretreatment
Treatment
Posttreatment
(21-Day Cycles)
Period
Screening
Cycle 1
Cycle 2 Through Last Cycle
End of 
Treatmenta
Follow-up
Day
Days −28
to −1
Day 1
Day 8
Day 1
Day 8
30 Days 
(± 7) After 
Last Dose
Every 
12 Weeks 
From 
EOT Visit 
(± 7)
Notes
Weight
X
X
X
X
ECGc
X
X
QOL questionnairesd
X
X
X
Hematology
X
X
X
X
X
X
See Section 6.3.5
Chemistry
X
X
X
X
X
X
See Section 6.3.5
Creatinine clearance
X
PT/INR, PTTe
X
LDH and uric acidf
X
Hepatitis and HIV 
testing
X
See Table 4
Blood sample for 
UGT1A1 genotyping
X
Urinalysis
X
See Table 4
FSH
X
Conduct as needed 
per Appendix 3 for 
determination of 
childbearing 
potential

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Phase
Pretreatment
Treatment
Posttreatment
(21-Day Cycles)
Period
Screening
Cycle 1
Cycle 2 Through Last Cycle
End of 
Treatmenta
Follow-up
Day
Days −28
to −1
Day 1
Day 8
Day 1
Day 8
30 Days 
(± 7) After 
Last Dose
Every 
12 Weeks 
From 
EOT Visit 
(± 7)
Notes
Serum pregnancy testg
X
For female patients 
of childbearing 
potential
Urine pregnancy testh
X
X
X
X
PKi
X
X
See footnote
X
Immunogenicityj
X
See footnote
X
Blood samples for 
biomarkers
X
Xk
Optional genomic 
research (biomarker)
Xl
Tumor tissue for EGFR, 
ALK, or PD-L1 testing 
if status unknownm
X
Tumor tissue for Trop-2 
and other biomarkers 
(archival or newly 
acquired)n
X
SG administration
X
X
X
X
Docetaxel administration
X
X
CT or MRI tumor 
assessmentso
X
Throughout study

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Phase
Pretreatment
Treatment
Posttreatment
(21-Day Cycles)
Period
Screening
Cycle 1
Cycle 2 Through Last Cycle
End of 
Treatmenta
Follow-up
Day
Days −28
to −1
Day 1
Day 8
Day 1
Day 8
30 Days 
(± 7) After 
Last Dose
Every 
12 Weeks 
From 
EOT Visit 
(± 7)
Notes
Bone scan, whole body 
bone MRI, or 18F-FDG 
PET scanp
X
As clinically indicated
If known or 
suspected bone 
metastasis
Adverse events
X
Throughout study
Xq
Prior and concomitant 
medications
X
Throughout study
Subsequent anticancer 
therapy
X
Survival information
X
ADA = antidrug antibody; ALK = anaplastic lymphoma kinase; C = cycle; CR = complete response; CT = computed tomography; D = day; ECG = electrocardiogram; 
ECOG = Eastern Cooperative Oncology Group; EGFR = epidermal growth factor receptor; EORTC QLQ-C30 v3 = European Organisation for Research and Treatment of Cancer 
Quality of Life Questionnaire-Core 30 Version 3; EOT = end of treatment; EQ-5D-3L = EQ-5D-3 level; FDG = fluorodeoxyglucose (18F); FFPE = formalin-fixed, 
paraffin-embedded; FSH = follicle-stimulating hormone; INR = international normalized ratio; IV = intravenous; LDH = lactate dehydrogenase; MRI = magnetic resonance 
imaging; NSCLC = non-small cell lung cancer; NSCLC-SAQ = Non–small Cell Lung Cancer Symptom Assessment Questionnaire; PD = progressive disease; PD-1 = programmed 
death protein 1; PD-L1 = programmed death ligand 1; PET = positron emission tomography; PGIC = Patient Global Impression of Change; PGIS = Patient Global Impression of 
Severity; PK = pharmacokinetic; PR = partial response; PRO-CTCAE = Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events; 
PT = prothrombin time; PTT = partial thromboplastin time; QOL = quality of life; SAE = serious adverse event; SG = sacituzumab govitecan; UGT1A1 = uridine diphosphate 
glucuronosyltransferase 1A1
Treatment visit windows are permitted either 1 day before or within 2 days after scheduled visits and ± 7 days for imaging.
a
An EOT visit will occur 30 days (± 7) after the last dose of study drug.
b
Vitals to be assessed at screening and at predose during treatment.
c
Twelve (12)-lead ECG will be obtained at screening and prior to infusion on C1D1. Abnormal findings should be evaluated as clinically indicated, including repeated ECGs. 
ECGs may be performed at other time points during the study if clinically indicated. See Section 6.3.4 for further information.
d
EQ-5D-3L, NSCLC-SAQ, EORTC QLQ-C30 v3, PGIS, PGIC, and PRO-CTCAE will be assessed on Day 1 prior to dosing of every cycle for the duration that patients are 
receiving SG or docetaxel treatment until and at the EOT visit. The QOL assessments will be conducted before other study procedures occur, including study drug 
administration.

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e
PT/INR and PTT testing will be conducted at screening and as clinically indicated. See Section 6.3.5 for further information.
f
LDH and uric acid testing will be conducted at screening and as clinically indicated. See Section 6.3.5 for further information.
g
Serum pregnancy test will be conducted at screening as discussed in Appendix 3.
h
During posttreatment, pregnancy testing will continue every 28 days after the last dose of study drug up to 6 months after the last dose of study drug per the duration of 
required contraception as discussed in Appendix 3. Testing during the posttreatment period may be performed at home and the result self-reported by the patient. See 
Section 7.4.2.3 for pregnancy reporting. If a urine pregnancy test is positive or equivocal, a confirmatory serum pregnancy test will be required.
i
Serum samples for PK analysis will be collected for patients who receive SG. Collection times for PK samples are at predose and after the end of infusion on C1D1 and C1D8 
and on Day 8 of Cycles 2, 6, and 10. Thereafter, PK samples will be collected at predose on Day 8 every 8 cycles (eg, C18D8, C26D8, etc) and at the EOT visit. The 
collection window is within 30 minutes prior to the start of infusion for predose samples and within 10 minutes after the end of infusion for postdose samples.
j
Serum samples for immunogenicity (ADA) analysis will be collected for patients who receive SG. Collection times for ADA samples are at predose on C1D1 and on Day 8 of 
Cycles 2, 6, and 10. Thereafter, samples will be collected at predose on Day 8 every 8 cycles (eg, C18D8, C26D8, etc) and at the EOT visit. The collection window for ADA 
sample is within 30 minutes prior to the start of infusion for predose samples.
k
Sample to be collected at screening and at predose on Day 1 of Cycles 2 and 3.
l
If the optional genomic sample is not collected at C1D1, it may be collected at any other study visit.
m
Local tumor tissue testing will be conducted according to the study procedures table if EGFR, ALK, or PD-L1 status is unknown. If local testing is unavailable, tumor tissue 
testing can be performed by the central laboratory. For patients with squamous cell carcinoma, EGFR and ALK testing is optional.
n
Archival tumor tissue (FFPE block) that was obtained preferably within 12 months prior to initial dosing (C1D1) or newly acquired tumor tissues from an evaluable core or 
excisional biopsy collected from patients within signing of the informed consent to prior to initial dosing (C1D1) may be submitted to the central laboratory. Tissue samples 
older than 12 months are acceptable. If tumor blocks are not available, it is recommended to submit freshly-cut unstained slides, sections of 4-5-micron thickness, serially cut 
from a single FFPE block and mounted on positively charged slides. Refer to the Laboratory Manual for further details. All efforts should be made to submit tumor tissue to 
the central laboratory. Consult with the sponsor if a sample is unavailable and the patient is unwilling to undergo a biopsy procedure.
o
CT or MRI scans with IV contrast (unless contrast use is medically contraindicated) of chest, abdomen, pelvis, and any other involved disease sites (brain MRI required if 
clinically indicated, as determined by the investigator during screening, on-treatment, follow-up, and confirmation of response; brain MRI required if positive at screening, as 
determined by the investigator during on-treatment and follow-up. Once received at post-screening time point, examination will be required at all subsequent time points) are 
required in all patients at screening and every 6 weeks for first 12 months, and then every 9 weeks from the date of randomization until the occurrence of radiologic PD per 
RECIST Version 1.1 criteria requiring discontinuation of treatment. For each patient, the same imaging technique should be used throughout the study. Clinical progression 
leading to patient discontinuation should be documented by CT or MRI scan of target lesions if clinically feasible. Patients who discontinue treatment due to toxicity or for 
any reason other than objective progression will continue to obtain radiologic response assessments according to the protocol-required schedule until radiologic PD or 
initiation of subsequent anticancer therapy. For patients with evidence of CR and PR, a confirmatory scan must be obtained a minimum of 4 to 6 weeks after initial 
documentation of response. Additional CT or MRI scans may be performed at the discretion of the investigator to assess disease status as medically indicated. These results 
should be recorded. All radiology images and reports for screening, response, and progression will be provided to the central imaging vendor and held for potential further 
review.
p
If a patient has known or suspected bone metastasis, a bone scan (99m-technetium polyphosphonate scintigraphy, whole body bone MRI, or 18F-NaF/FDG PET) to assess 
bone metastases will be performed within 6 weeks before C1D1 (historical scans are acceptable). Bone scan, whole body bone MRI, or 18F-FDG-PET scan required if 
clinically indicated, as determined by the investigator. For patients with evidence of complete response (CR) and partial response (PR), a confirmatory scan must be obtained 
a minimum of 4 to 6 weeks after initial documentation of response. In patients whose body CT/MRI scans indicate that CR has been achieved, a bone scan or 18F-NaF/FDG 
PET will be required at confirmation of CR to exclude the presence of new bone metastases or if clinically indicated, and will occur within 1 week, but not more than 2 weeks 
following a CR, as assessed by the investigator. For each patient, the same imaging technique used at screening should be used throughout the study to ensure comparability. 
Lesions detected on bone scans must be followed with cross-sectional imaging. All radiology images and reports for screening, response, and progression will be provided to 
the central imaging vendor and held for potential further review.
q
Only SAEs should be reported (see Section 7.3.3).

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1.
INTRODUCTION
1.1.
Background
Lung cancer is the leading cause of cancer-related mortality worldwide. It was estimated that in 
2020, there were over 2 million new cases of lung cancer and approximately 1.8 million deaths 
worldwide {International Agency for Research on Cancer (IARC) 2020}. In the United States 
(US) in 2021, it is estimated that there will be over 235,000 new cases of lung cancer and over 
131,000 deaths {American Cancer Society 2021}. Approximately 80% to 85% of all lung 
cancers are non-small cell lung cancer (NSCLC) {Ettinger 2019} and more than half of these are 
still identified at an advanced stage {Siegel 2019}.
Several genomic alterations have been identified in NSCLC that have an impact on therapy 
selection and molecular testing is part of the standard of care in the evaluation of NSCLC. 
Among these, epidermal growth factor receptor (EGFR) gene mutations (10% to 50% of 
NSCLC) and anaplastic lymphoma kinase (ALK) gene rearrangements (5%) are most common 
and are associated with response to EGFR and ALK tyrosine kinase inhibitors (TKIs), which are 
widely approved and in clinical use as first-line agents in these subtypes. Other genomic 
alterations such as ROS proto-oncogene 1 (ROS1), gene rearrangements, proto-oncogene B-raf 
(BRAF) point mutations MET exon 14 skipping, RET, and neurotrophic tyrosine receptor kinase 
(NTRK) mutations occur more rarely but have approved therapies targeting such alterations. 
Unfortunately, only a minority of new cases of NSCLC harbor actionable genomic alterations 
although the list is growing.
Recent advances with immune checkpoint inhibitor therapy have dramatically improved the 
prognosis of advanced lung cancer and these immune checkpoint inhibitor therapies, as 
monotherapy (programmed death protein1 [PD-1] ≥ 50%) or in combination with 
platinum-doublet chemotherapy (regardless of programmed death ligand 1 [PD-L1] expression), 
are mainly used in the frontline metastatic setting based on results of KN-024, KN-042, KN189, 
and KN407 and similar studies for patients who do not have actionable genomic alterations. 
Platinum doublet chemotherapy with or without PD-L1 inhibitor remains the standard treatment 
for patients with actionable genomic alterations when they have failed treatment with targeted 
agents or such treatment is not available. After failure of immune checkpoint inhibitor therapy 
and platinum-based chemotherapy, there are limited treatment options for most patients. 
According to National Comprehensive Cancer Network guidelines, the use of single-agent 
chemotherapy (including taxanes) is the standard of care for patients with recurrent or metastatic 
NSCLC after failure of platinum-based therapy and/or immune checkpoint therapy regardless of 
presence of genomic alterations and PD-L1 status {Ettinger 2019}. The main options for 
single-agent chemotherapy in this setting generally include docetaxel (with or without 
ramucirumab) and pemetrexed (for nonsquamous tumors if not previously used). In a study of 
docetaxel versus best supportive care in relapsed NSCLC, the median progression-free survival 
(PFS) was approximately 3 months with a median overall survival (OS) of approximately 6 to 
8 months {Shepherd 2000}. These numbers have been borne out in more contemporaneous 
studies with docetaxel following failure of platinum-based regimens in NSCLC {Horn 2017, 

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Mazieres 2021}. Although docetaxel is considered standard of care in patients failing 
platinum-based regimens and checkpoint inhibitors, novel agents remain a significant unmet 
medical need in subsequent treatment of advanced NSCLC.
1.2.
Sacituzumab Govitecan
1.2.1.
General Information
Sacituzumab govitecan (SG) is an antibody-drug conjugate (ADC) composed of the following 
3 components:
1) The humanized monoclonal antibody, hRS7 IgG1κ, which binds to trophoblast cell surface 
antigen-2 (Trop-2), a transmembrane calcium signal transducer that is overexpressed in many 
epithelial cancers, including triple-negative breast cancer
2) The camptothecin-derived agent SN-38, a topoisomerase I inhibitor
3) A hydrolyzable linker, with the company designation as CL2A that links the humanized 
monoclonal antibody to SN-38
Binding of Trop-2 by the parental RS7 antibody has been shown to result in internalization and 
processing of the antibody by the targeted cells {Shih 1994, Stein }. Because of its hydrolyzable 
linker, SG will release its SN-38 payload both intra- and extracellularly in the tumor 
microenvironment {Goldenberg 2015, Govindan 2013}. Sacituzumab govitecan delivers 
significantly greater amounts of SN-38 to a Trop-2-expressing tumor than conventional 
irinotecan chemotherapy {Sharkey 2015}. The extracellular release of SN-38 from SG also 
allows for bystander killing of Trop-2 negative tumor cells {Lopez 2020, Perrone 2020, Zeybek 
2020}. Thus, SG can deliver cytotoxic chemotherapy to tumors, including adjacent cancer cells, 
in concentrations that are higher than those with standard chemotherapy and may reduce toxic 
effects in normal tissues that do not express the target.
For further information on SG, refer to the current investigator’s brochure (IB).
1.2.2.
Nonclinical Pharmacology and Toxicology
In the nonclinical program, SG demonstrated antitumor activity and significant inhibition of 
tumor growth in various epithelial cancer xenograft models compared to controls; SG also 
demonstrated low cytotoxicity in multiple cell lines representative of different epithelial tumors 
(half-maximal inhibitory concentration values ranged from 1.95 nM to 23.14 nM). Nonclinical 
studies confirmed that the majority of SN-38 administered as SG remains bound to the ADC in 
the serum and is not circulating as the free cytotoxic payload.
No evidence of hematological toxicity and no abnormal histology findings were observed in 
nonclinical acute toxicity studies in Swiss-Webster Mice with SG at doses of up to 
750 mg/kg/dose (ie, cumulative doses of up to 1500 mg/kg). In nonclinical toxicology studies 
with Cynomolgus monkeys, SG administered 50 mg/kg/dose (human equivalent 

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dose = 16 mg/kg/dose) for 4 treatment cycles (Days 1 and 8 of a 21-day cycle) was considered a 
no observed adverse effect level and 120 mg/kg/dose administered 3 days apart (1 treatment 
cycle) was associated with mortality. In monkeys, target organs included the gastrointestinal tract 
(necrosis, erosions, inflammation, fibrosis, hemorrhage, and edema), bone marrow (reduced 
cellularity) with concomitant reductions in red blood cells, white blood cells, and platelets; 
female reproductive tract; lymphoid organs (lymphoid depletion); kidney (periarteritis); and skin 
(hair loss, pigmentation).
SN-38 is a camptothecin and hence might be carcinogenic and is a known developmental 
toxicant {CAMPTOSAR 2014}.
For additional information on the SG nonclinical program, refer to the current IB.
1.2.3.
Clinical Studies of Sacituzumab Govitecan
Based on the results of Studies IMMU-132-05 and IMMU-132-06, SG has been approved in the 
US for the treatment of adult patients with metastatic triple-negative breast cancer (mTNBC) 
who have received 2 or more prior therapies, at least 1 of them for metastatic disease and has 
received accelerated approval in the US for the treatment of adult patients with metastatic 
urothelial cancer (mUC) who have previously received a platinum-containing chemotherapy and 
either PD-1 or PD-L1 inhibitor.
As of January 2021, clinical data are available for 3 clinical studies (2 completed and 1 ongoing) 
in which 795 patients were treated with SG:

IMMU-132-01, a Phase 1/2, open-label, basket study in patients with metastatic epithelial 
cancers that were either relapsed or refractory after at least 1 standard therapeutic regimen for 
their tumor type (N = 495). Fifty-four patients with NSCLC were enrolled; 8 at a starting 
dose of 8 mg/kg and 46 at a starting dose of 10 mg/kg on Days 1 and 8 of 21-day cycles.

IMMU-132-05, a Phase 3 study of SG compared with single-agent chemotherapy in patients 
with unresectable locally advanced or mTNBC who had received at least 2 prior therapies 
(N = 582 including 258 with SG and 224 with single-agent chemotherapy); included a 
pharmacokinetic (PK)-electrocardiogram (ECG) substudy of 29 patients from the SG-treated 
group to assess the effects of SG on cardiac repolarization (QTc interval) and other ECG 
parameters.

IMMU-132-06, an ongoing Phase 2 study in patients with locally advanced or mUC 
(N = 135) that included: 1) a cohort of patients who progressed after prior platinum-based 
and PD-1/PD-L1 inhibitor therapy (N = 113) and 2) a cohort of patients who were platinum 
ineligible and received PD-1/PD-L1 inhibitor therapy in the first line metastatic setting 
(N = 22).
Summaries of PK, clinical efficacy, and clinical safety are provided in the following sections. 
For additional information on the SG clinical program, refer to the current IB.

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1.2.3.1.
Summary of Clinical Safety
Unresectable Locally Advanced/Metastatic Triple-Negative Breast Cancer and Locally 
Advanced/Metastatic Urothelial Cancer
The safety profile for SG was similar in the treatment of mTNBC and mUC. The most common 
adverse events (AEs) were nausea, diarrhea, neutropenia, fatigue, alopecia, anemia, vomiting, 
and constipation. The most clinically relevant Grade 3 or Grade 4 AEs with SG were neutropenia 
and diarrhea. The most frequent AEs that led to treatment modification were neutropenia and 
diarrhea. The frequent AEs leading to permanent discontinuation of study drug were fatigue, 
diarrhea, pneumonia, and neutropenia.
Neutropenia occurred in the first cycle of treatment and resolved within approximately 1 week of 
onset. Most cases of neutropenia were not febrile, were nonserious, and could be managed with 
granulocyte-colony stimulating factor administration and/or dose reduction after Cycle 1.
Diarrhea with SG occurred within the first treatment cycle (median time of 12 days to first event) 
and resolved within approximately 1 week of onset. Most of the cases of diarrhea were 
nonsevere, nonserious, and did not lead to either a treatment interruption or dose reduction.
Higher incidences of neutropenia, febrile neutropenia, and anemia were seen in patients who 
were homozygous for the uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1)*28 allele 
compared with patients who were heterozygous for the UGT1A1*28 allele and patients who 
were homozygous for the wild-type allele.
No evidence for QTc prolongation was seen with SG in the PK-ECG substudy in the mTNBC 
study.
For further information on SG, refer to the current IB.
Non-Small Cell Lung Cancer
In Study IMMU-132-01 (data cutoff of 01 March 2019), the most common AEs (≥ 25% of 
patients) reported in NSCLC patients (N = 54) were nausea (83.3%), diarrhea (66.7%), fatigue 
(51.9%), alopecia (48.1%), vomiting (44.4%), constipation (42.6%), decreased appetite (38.9%), 
anemia (35.2%), and neutropenia (29.6%). The frequencies of these most common AEs were 
similar between the patients with NSCLC group and the overall population across multiple tumor 
types and starting doses (N = 495; 402 patients received 10 mg/kg of SG, 81 received 8 mg/kg of 
SG, and 12 received ≥ 12 mg/kg of SG) with the exception of nausea and neutropenia 
(the incidence of nausea was > 10% higher in patients with NSCLC versus the overall population 
and neutropenia was ≥ 10% higher in the overall population versus patients with NSCLC). These 
AEs are consistent with the known safety profile of SG.

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For patients with NSCLC, Grade 3 or higher AEs were reported in 79.6% of patients, serious 
AEs (SAEs) in 42.6%, AEs leading to study drug discontinuation in 3.7%, and AEs leading to 
dose interruption in 42.6%. The incidence of these was similar to or lower than the overall 
population.
No events of pneumonitis or interstitial lung disease were reported in patients with NSCLC.
1.2.3.2.
Summary of Clinical Efficacy
Non-Small Cell Lung Cancer
Sacituzumab govitecan has been evaluated in patients with metastatic NSCLC in 2 clinical 
studies: IMMU-132-01 (completed; 54 patients enrolled) and IMMU-132-11 (ongoing; 
preliminary results are not available yet).
In IMMU-132-01, objective response rate (ORR) based on local response assessment was 16.7% 
for the NSCLC population; all responses were partial responses (PRs). The majority of patients 
had at least a 30% reduction in the size of the target lesion.
Median duration of response (DOR) by local assessment was 6.0 months (range: 2.5 to 21.0). 
The Kaplan-Meier estimate of the percentage of patients with a response of 6 months was 44.4% 
(95% CI: 13.6, 71.9).
Unresectable Locally Advanced/Metastatic Triple-Negative Breast Cancer
In Study IMMU-132-05, a statistically significant and clinically meaningful benefit for SG over 
single-agent chemotherapy was seen for PFS (hazard ratio [HR], 0.41; P < 0.0001) and OS 
(HR: 0.48; P < 0.0001). Significant benefits with SG for PFS and OS were seen irrespective of 
BRCA status and in all other prespecified subgroups, including by age and other previous 
treatments for mTNBC, including prior treatment with PD-1/PD-L1. The ORR was also 
significantly improved with SG versus single-agent chemotherapy in Study IMMU-132-05 
(35% vs 5%).
In Study IMMU-132-01, ORR and median DOR for patients with mTNBC were 33.3% and 
7.7 months, respectively. Median PFS and median OS were 5.6 and 13.0 months, respectively.
Locally Advanced/Metastatic Urothelial Cancer
In patients who progressed after prior platinum-based and PD-1/PD-L1 inhibitor therapy, ORR 
was 27% in Studies IMMU-132-01 and IMMU-132-06 with an associated median DOR of 
20 months (mUC subgroup N = 15; median follow-up duration of approximately 12 months) and 
7.2 months (median follow-up duration of 9.1 months), respectively. The clinical benefit rates 
for Studies IMMU-132-01 and IMMU-132-06 were 44.4% and 37.2%, respectively.

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1.3.
Information About Docetaxel
1.3.1.
Description of Docetaxel
Docetaxel is an anticancer cytotoxic agent classified as an antimicrotubule inhibitor. Docetaxel is 
indicated for the treatment of multiple solid tumors, including advanced NSCLC, as a single 
agent {Taxotere® 1995, Taxotere® 1996}.
1.4.
Rationale for This Study
There remains a high unmet need for novel agents in the treatment of advanced NSCLC 
particularly in patients who have failed treatment with immune checkpoint inhibitors and 
platinum-based chemotherapy due to poor outcomes with current treatment in this patient 
population. Even though much progress has been made in development of targeted treatments for 
specific genomic alterations, eventually most patients have progressive disease (PD) on these 
treatments after which they are treated with platinum chemotherapy and immune checkpoint 
inhibitors. For patients whose cancers have failed the aforementioned treatments, very few 
treatment options exist, and they represent a patient population of high unmet medical need. 
Sacituzumab govitecan has demonstrated encouraging activity and a manageable safety profile in 
advanced NSCLC and thus warrants further evaluation. A Phase 3, randomized, multicenter 
study is the most reliable design, with randomization and a global footprint providing 
minimization of potential bias. Docetaxel, the comparator agent for this study, is the appropriate 
standard of care in this setting and has been evaluated in numerous studies in patients with 
NSCLC, so that both its efficacy and safety profiles are well established. Overall survival as the 
primary endpoint remains the most robust and unbiased endpoint in cancer clinical studies, and 
the endpoint most important to both patients and clinicians. The current study design will 
therefore provide a reliable assessment of SG in the treatment of NSCLC in patients with PD 
after a platinum-based regimen and a checkpoint inhibitor.
1.5.
Rationale for Dose Selection of Sacituzumab Govitecan
In Study IMMU-132-01 in patients with diverse metastatic solid cancers including mTNBC and 
NSCLC, dose escalation was performed according to a standard 3 + 3 design and based on 
planned initial dose levels of 8, 12, and 18 mg/kg. An SG dose of 12 mg/kg was formally 
identified as the maximum tolerated dose (MTD) but was associated with dose delays and 
reductions in several patients. In order to determine a maximum acceptable dose, additional 
patients were treated at the 8 mg/kg dose level and an intermediate dose cohort of 10 mg/kg was 
added. The 8 mg/kg and 10 mg/kg dose levels were shown to be better tolerated in the first cycle 
than the formally determined MTD of 12 mg/kg, allowing repeated cycles with a better safety 
profile. There were no major differences in safety (worsening of AE incidences or severity) 
between the 8 mg/kg and the 10 mg/kg dose levels, and there was a trend for better efficacy in 
patients with mTNBC with the 10 mg/kg dose {Ocean 2017}. Based on these results, the 
10 mg/kg dose of SG was selected as the maximum acceptable dose.

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1.6.
Rationale for Open-Label Study Design
The treatment schedules for SG and docetaxel are different. Sacituzumab govitecan is 
administered on Days 1 and 8 of a 21-day cycle while docetaxel is administered only on Day 1 of 
a 21-day cycle. Moreover, docetaxel requires premedication with corticosteroids 3 days prior to 
treatment administration, which may be difficult to implement and place undue burden on 
patients if given in a blinded fashion. 
1.7.
Risk/Benefit Assessment for the Study
The outlook for patients with NSCLC who have developed progressive neoplastic disease despite 
treatment with a platinum-based regimen and a checkpoint inhibitor is dire, with median survival 
times measured in months. In addition, both progressive neoplastic disease in the lung as well as 
metastatic disease in patients with advanced NSCLC produce severe morbidity and a markedly 
diminished quality of life (QOL). Given the demonstrated response and clinical benefit rates for 
SG and the ongoing need for novel therapies in the treatment of advanced lung cancer, the 
risk/benefit equation favors the continued development of SG in the population of patients with 
NSCLC who have progressive neoplastic disease despite treatment with a platinum-based 
regimen and a checkpoint inhibitor.
An infectious disease pandemic may pose additional risks to study drug availability, the study 
visit schedule, and adherence to protocol-specified safety monitoring or laboratory assessments. 
Refer to Appendix 2 for further details on the risks and risk mitigation strategy.
1.7.1.
Clinical Data for Docetaxel
Docetaxel is approved for use as monotherapy in multiple solid tumors including NSCLC, head 
and neck squamous cell carcinoma, breast cancer, hormone refractory prostate cancer, and 
gastric adenocarcinoma. Docetaxel is also widely used as standard of care in multiple solid 
tumors, including mUC and mNSCLC, who fail frontline chemotherapy and/or immune 
checkpoint therapy {Taxotere® 1995, Taxotere® 1996}.
The most common AEs across all docetaxel indications are infections, neutropenia, anemia, 
febrile neutropenia, hypersensitivity, thrombocytopenia, neuropathy, dysgeusia, dyspnea, 
constipation, anorexia, nail disorders, fluid retention, asthenia, pain, nausea, diarrhea, vomiting, 
mucositis, alopecia, skin reactions, and myalgia {Taxotere® 1995, Taxotere® 1996}. Docetaxel 
is contraindicated in patients with neutrophil counts less than 1500 cells/mm3 and in patients 
with hypersensitivity to docetaxel or polysorbate 80 {Taxotere® 1995, Taxotere® 1996}. 
Docetaxel carries a black box warning for toxic deaths, hepatotoxicity, neutropenia, 
hypersensitivity reactions, and fluid retention. In addition, cutaneous reactions, severe skin 
toxicity, neurologic reactions (including paresthesia, dysesthesia, and pain), asthenia, and 
potential fetal harm have been observed with docetaxel.
Docetaxel has been evaluated in several randomized clinical studies in patients with NSCLC 
following failure of platinum-based regimens, with early studies comparing docetaxel to other 
chemotherapy agents and more recent studies comparing docetaxel to checkpoint inhibitors.

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In a study comparing docetaxel to best supportive care, docetaxel produced an ORR of 7.1% and 
a median OS of 7 months; 1-year survival was 37% {Shepherd 2000}. In the TAX 320 study 
comparing docetaxel to either vinorelbine or ifosfamide, docetaxel produced an ORR of 6.7% 
with PFS of 26 weeks; 1-year survival was 32% {Fossella 2000}. In a study comparing 
docetaxel to pemetrexed, docetaxel was associated with an ORR of 8.8% and median OS of 
7.9 months {Hanna 2004}.
More contemporaneous studies of docetaxel versus checkpoint inhibitors have shown similar 
results. A pooled analysis of the CheckMate 017 and CheckMate 057 studies of nivolumab 
versus docetaxel in platinum failures, the 1-year PFS for docetaxel was 9% (in nonsquamous 
NSCLC) and 14% in squamous NSCLC {Horn 2017}. In the OAK and POPLAR studies 
comparing atezolizumab and docetaxel, docetaxel had median OS values of 9.7 and 9.8 months, 
respectively. In the Keynote 010 study comparing pembrolizumab to docetaxel, docetaxel was 
associated with a median OS of 8.2 months, a median PFS of 4.1 months, and an ORR of 8% 
{Mazieres 2021}.
In summary, docetaxel is used as a standard of care option for second and later lines of therapy 
for multiple solid tumor types after frontline chemotherapy and/or immune checkpoint therapy 
and has been evaluated extensively in patients with NSCLC.
1.8.
Compliance
This study will be conducted in compliance with this protocol, Good Clinical Practice (GCP), 
and all applicable regulatory requirements.

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2.
OBJECTIVES AND ENDPOINTS
Primary Objective
Primary Endpoint

To compare the OS of SG versus docetaxel.

OS is defined as the time from the date of 
randomization until death due to any cause in the 
Intent-to-Treat (ITT) Analysis Set.
Secondary Objectives
Secondary Endpoints
To compare the effect of SG versus docetaxel on the 
following:

PFS as assessed by the investigator per 
Response Evaluation Criteria in Solid Tumors 
(RECIST) Version 1.1.

PFS is defined as the time from the date of 
randomization until the date of objective disease 
progression or death (whichever comes first) as 
assessed by the investigator per RECIST 
Version 1.1.

ORR as assessed by the investigator per 
RECIST Version 1.1.

ORR is defined as the proportion of patients who 
achieve a complete response (CR) or PR that is 
confirmed at least 4 weeks later as assessed by the 
investigator per RECIST Version 1.1.

DOR as assessed by the investigator per 
RECIST Version 1.1.

DOR is defined as the time from the first 
documentation of CR or PR to the earlier of the first 
documentation of PD or death from any cause 
(whichever comes first) as assessed by the 
investigator per RECIST Version 1.1.

Disease control rate (DCR) as assessed by the 
investigator per RECIST Version 1.1.

DCR is defined as the proportion of patients who 
achieve a CR, PR, or stable disease (SD) as assessed 
by the investigator per RECIST Version 1.1.

Safety and tolerability.

Incidence of treatment-emergent adverse events 
(TEAEs) and clinical laboratory abnormalities.

QOL using NSCLC Symptom Assessment 
Questionnaire (NSCLC-SAQ).

Time to first deterioration in shortness of breath 
domain as measured by NSCLC-SAQ.

Time to first deterioration in NSCLC-SAQ total 
score.

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Exploratory Objectives
Exploratory Endpoints

To characterize the PK and immunogenicity of 
SG.

Peak (Cmax) and trough (Ctrough) concentrations over 
time and antidrug antibodies (ADAs) over time.

To assess disease-related symptoms and 
health-related QOL using EQ-5D-3 level 
(EQ-5D-3L); NSCLC-SAQ; the European 
Organisation for Research and Treatment of 
Cancer Quality of Life Questionnaire-Core 30 
Version 3 (EORTC QLQ-C30 v3); Patient 
Global Impression of Severity (PGIS); and 
Patient Global Impression of Change (PGIC).

Mean change from baseline of total score and all 
domains of NSCLC-SAQ not assessed as secondary 
endpoints.

Mean change from baseline of all domains of 
EORTC QLQ-C30 v3.

The proportion of patients with meaningful change 
in each QOL domain while on treatment.

Time to first improvement and time to first 
deterioration in each QOL domain not assessed as 
secondary endpoints.

To assess and compare treatment-related 
symptoms using Patient-Reported Outcomes 
version of the Common Terminology Criteria 
for Adverse Events (PRO-CTCAE).

Frequency, severity, or interference of 
treatment-related symptoms.

To assess tumor expression of Trop-2 as a 
potential predictive biomarker of response to 
SG.

To explore blood and tumor biomarkers that 
may be associated with response to SG 
treatment.

Correlation of clinical response with baseline tumor 
Trop-2 expression.

Correlation of clinical response with tumor, tumor 
microenvironment, and blood biomarkers at baseline 
and after SG treatment.

Clearance of circulating tumor DNA upon SG 
treatment.

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3.
STUDY DESIGN
3.1.
Study Design Overview
Study GS-US-577-6153 is an open-label, global, multicenter, randomized, Phase 3 study to 
compare the efficacy and safety of SG versus docetaxel in patients with advanced or metastatic 
NSCLC with progression on or after platinum-based chemotherapy and anti-PD-1/PD-L1 
immunotherapy received either in combination or sequentially. Patients with actionable genomic 
alterations will also be included if they have received prior treatment with an appropriate TKI 
(see Appendix 8).
This study will be conducted in approximately 250 centers globally. Patient participation will 
include screening, randomization, treatment, and follow-up. Screening will last no longer than 
28 days to confirm eligibility and establish disease characteristics prior to randomization and 
treatment. The study procedures table and study schema are presented in Table 1 and Figure 1, 
respectively.
Approximately 580 eligible patients will be randomly assigned in a 1:1 ratio to receive either SG 
(Investigational Arm A) or docetaxel (Control Arm B). Randomization will be stratified based on 
histology (squamous vs nonsquamous), response to last prior immune therapy received (best 
response PD/SD vs CR/PR on immune therapy), and if they have received prior therapy for 
actionable genomic alteration (yes vs no). 
The primary endpoint of the study is OS. Secondary efficacy endpoints are PFS, ORR, DOR, and 
DCR as assessed by the investigator per RECIST Version 1.1; time to first deterioration in 
NSCLC-SAQ total score; and time to first deterioration in shortness of breath as measured by 
NSCLC-SAQ. Safety will be assessed by the reporting of AEs, assessments of vital signs, 
laboratory results, and extent of exposure to study drug. Additional QOL assessments will be 
conducted. Pharmacokinetics, ADA, and various biomarkers will also be assessed.
Sacituzumab govitecan will be administered at 10 mg/kg via IV infusion on Days 1 and 8 of a 
21-day cycle. Docetaxel will be administered at 75 mg/m2 via IV infusion on Day 1 of a 21-day 
cycle. Patients will receive study drug until PD, death, unacceptable toxicity, or another 
treatment discontinuation criterion is met. Follow-up will begin at the time of the completion of 
the end of treatment (EOT) visit, which will occur 30 days (± 7) after the last dose of study drug. 
All patients will be followed for survival until 1 of the discontinuation criteria from the study is 
met.
An independent data monitoring committee (DMC) will be convened at regular intervals to 
assess the progress of this study, review safety data, and conduct the interim efficacy analysis.

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Extension Study in China
After the enrollment period of the global study is completed, subjects from China will continue 
to be enrolled in the extension study, to collect additional efficacy and safety data in patients 
from mainland China in order to support future local registration in China. The extension study 
will be identical to the global study (eg, inclusion and exclusion criteria, study endpoints, 
primary and secondary objectives, study procedures), with the exception of an additional 
supplemental statistical analysis plan (SAP) for Chinese patients. 
3.2.
Study Treatments
This is a randomized, open-label study. Eligible patients will be randomly assigned (1:1) to 
receive either:

Sacituzumab govitecan 10 mg/kg via IV infusion on Days 1 and 8 of a 21-day cycle 
(ie, 2 weekly doses plus 1 week without treatment)

Docetaxel 75 mg/m2 via IV infusion on Day 1 of a 21-day cycle (ie, once every 3 weeks)
The details of study drugs administered in this study are described in Section 5. Details regarding 
the formulation, packaging, and labeling of SG and docetaxel are provided in Sections 5.2 and 
5.7, respectively.
3.3.
Duration of Treatment
Patients will receive study drug until PD, death, unacceptable toxicity, or another treatment 
discontinuation criterion is met (see Section 3.4 for further details about discontinuation criteria).
Treatment with either SG or docetaxel beyond the initial investigator-assessed PD per RECIST 
Version 1.1 (Appendix 6) is permitted if there is evidence of clinical benefit per the investigator 
and the patient is tolerating study drug. The following clinical criteria should be met for patients 
to continue to receive treatment beyond the investigator-assessed progression. 

Absence of symptoms and signs indicating clinically significant progression of disease

No decline in performance status

Absence of symptomatic rapid disease progression requiring urgent medical intervention 
(eg, symptomatic pleural effusion, spinal cord compression)
Sponsor consultation is required before patients initiate any treatment beyond progression. If this 
occurs, the patient will remain in the study and continue to be monitored according to the study 
procedures table (Table 1). All patients will be followed for survival until 1 of the 
discontinuation criteria from the study is met (Section 3.4.2).

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3.4.
Discontinuation Criteria
3.4.1.
Discontinuation From Study Treatment
Study drug may be discontinued in the following instances:

Intercurrent illness that would, in the judgment of the investigator, affect assessments of 
clinical status to a significant degree.

Unacceptable toxicity, or toxicity that, in the judgment of the investigator, compromises the 
ability to continue study-specific procedures or is considered not to be in the patient’s best 
interest. Discontinuation criteria for toxicities, dose delays, or failure to resolve a toxicity are 
detailed in Section 5.5 and Section 5.10.

Initiation of alternative anticancer therapy, including any investigational agent

Disease progression with no evidence of clinical benefit (see Section 6.3.7)

Patient request to discontinue for any reason.

Patient noncompliance.

Pregnancy during the study (see Appendix 3).

Discontinuation of the study at the request of Gilead Sciences (hereafter referred to as 
Gilead) or an institutional review board (IRB) or independent ethics committee (IEC)

Lost to follow-up

Investigator or treating physician decision in the absence of any of the above
Study drug discontinuation should not result in patient discontinuation from the study and the 
patient should continue to be followed up in the study for PD and survival as per Section 3.4.4. 
Reasons for discontinuation from the study are outlined in Section 3.4.2.
3.4.2.
Discontinuation From the Study
Patients will discontinue the study under any of the following instances:

Death

Patient withdrawal of consent from the study

Lost to follow-up (Section 3.4.3)

Termination of the study at the request of Gilead or an IRB/IEC

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3.4.3.
Lost to Follow-up
Should the patient fail to return to the study site for a scheduled protocol-specific visit, sites will 
need to make at least 4 attempts by a combination of phone calls, text messages, email messages, 
etc to contact the patient to reschedule the study visit as well as confirm survival status. Sites 
must document all attempts to contact the patient. If a patient does not respond within 1 month 
after the fourth contact, the patient will be considered lost to follow-up. For patients who are 
considered lost to follow-up from the study prior to completion of all protocol-required visits for 
study assessments or survival follow-up as described in the study procedures table (Table 1), the 
investigator may search publicly available records (where permitted by local laws and 
regulations) to ascertain survival status unless the patient withdraws consent for such follow-up. 
This ensures reduced risk of missing critical efficacy data.
3.4.4.
Safety and Survival Follow-up
After treatment discontinuation (Section 3.4.1), all patients must complete an EOT visit 30 days 
(± 7) after the last dose of study drug. Patients will enter the follow-up period after completing 
the EOT visit, unless the patient explicitly indicates their desire to forego survival follow-up in 
writing to their study investigator. Follow-up assessments will be performed according to the 
study procedures table (Table 1). All patients will be followed for survival until 1 of the 
discontinuation criteria from the study is met (Section 3.4.2). For any patient who dies during the 
follow-up period, primary cause of death must be reported to the sponsor.
Patients who complete or withdraw from all other study assessments (eg, tumor assessments, 
study treatment) will enter long-term follow-up. Follow-up visits should be conducted every 
12 weeks from EOT visit (± 7 days) or more frequently until death or withdrawal of consent, 
whichever comes first. Visits will include documentation of survival status and documentation of 
subsequent anticancer therapy. For patients who discontinue from the study prior to completion 
of all protocol-required visits for study assessments or survival follow-up as described in the 
study procedures table (Table 1), the investigator may search publicly available records (where 
permitted by local laws and regulations) to ascertain survival status unless the patient withdraws 
consent for such follow-up. This ensures reduced risk of missing critical efficacy data.
3.5.
Definitions for End of Study
Individual Patients: Patients are considered to have reached the end of the study when they are 
no longer followed for long-term or survival follow-up due to the following reasons: death, 
patient withdrew consent, lost to follow-up, the sponsor terminated study.
For any patient who dies during the follow-up period, primary cause of death must be reported to 
the sponsor.
All Patients: The end of the entire study for all patients is defined as the date on which the last 
patient remaining on study completes the last study visit/call or when the sponsor decides to end 
the study. The sponsor reserves the right to terminate the study at any time for any reason 
(including safety).

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3.6.
Poststudy Care
Patients who discontinue study drug and agree to remain in the study will follow the 
requirements outlined in Table 1 for continued follow-up.
3.7.
Source Data
The source data for this study will be obtained from original records (eg, clinic notes, hospital 
records, patient charts), central laboratory, local laboratory, and/or specialty laboratory (for PK, 
ADA, and/or biomarker data) and/or additional biomarker testing, and interactive response 
technology (IRT).

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4.
PATIENT POPULATION
4.1.
Number of Patients and Patient Selection
Approximately 580 eligible patients will be enrolled in this study.
4.1.1.
Patient Replacement
Patients who discontinue before the end of the study will not be replaced.
4.2.
Inclusion Criteria
Patients must meet all of the following inclusion criteria at screening/Day −1 to be eligible for 
participation in this study (no waivers for patient eligibility will be offered or permitted):
1) Female or male patients, 18 years of age or older, able to understand and give written 
informed consent
2) Life expectancy of 3 months or more
3) Pathologically documented NSCLC with documented evidence of Stage 4 NSCLC disease 
at the time of enrollment (based on the American Joint Committee on Cancer, Eighth 
Edition).
4) EGFR, ALK, and PD-L1 results are required prior to enrollment (see Section 6.3.10). 
Resulting for other actionable genomic alterations is recommended and to be performed as 
per local standard of care and availability of targeted treatment. For patients with squamous 
cell carcinoma, EGFR and ALK testing is optional.
5) Must have progressed after platinum-based chemotherapy in combination with anti-
PD-1/PD-L1 antibody OR platinum-based chemotherapy and anti-PD-1/PD-L1 antibody
(in either order) sequentially.
•
Note: Includes patients who received prior platinum-based chemoradiotherapy (with or 
without maintenance anti-PD-1/PD-L1 antibody) for Stage 3 disease. To be considered 
to have progressed during or after prior treatment with platinum-based chemotherapy, 
patients should have either received prior platinum-based chemotherapy in the recurrent/
metastatic setting or have experienced disease progression within 6 months of last dose 
of platinum-based chemotherapy administered as part of concurrent chemoradiation for 
Stage 3 disease or as neoadjuvant or adjuvant therapy. To be considered to have 
progressed during or after prior treatment with an anti-PD-1/PD-L1 antibody, patients 
should have either received this therapy in the recurrent/metastatic setting or have 
experienced disease progression during “maintenance” treatment following concurrent 
chemoradiation for Stage 3 disease.
a) No additional treatments are allowed in the recurrent/metastatic setting for patients 
with no actionable genomic alterations.

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b) Patients with EGFR, ALK, or any other known actionable genomic alterations must
have also received treatment with at least 1 locally approved and available TKI
appropriate to the genomic alteration (see Appendix 8).
c) Documented radiographic disease progression while on or after receiving the most
recent treatment regimen for advanced or metastatic NSCLC.
6) Measurable disease based on computed tomography (CT) or magnetic resonance imaging
(MRI) as assessed by the investigator in accordance with per RECIST Version 1.1. Tumor
lesions situated in a previously irradiated area are considered measurable if progression has
been demonstrated in such lesions. Historical images within 28 days of the screening visit
may be accepted as a screening image if deemed acceptable in the opinion of the investigator.
7) Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1
(Appendix 5) before randomization.
8) Adequate hematologic counts without transfusional or growth factor support within 2 weeks
of study drug initiation (hemoglobin ≥ 9 g/dL, absolute neutrophil count ≥ 1500/mm3, and
platelets ≥ 100,000/μL).
9) Adequate hepatic function (bilirubin ≤ 1.5 upper limit of normal [ULN], aspartate
aminotransferase and alanine aminotransferase ≤ 2.5  ULN or ≤ 5  ULN if known liver
metastases, and serum albumin > 3 g/dL).

Note: The investigator should follow local practice guidelines and/or the docetaxel label
approved in the country of drug administration for assessing eligibility of patients for the
study.
10) Creatinine clearance of at least 30 mL/min as assessed by the Cockcroft-Gault equation
{Cockcroft 1976}.
11) Male patients and female patients of childbearing potential who engage in heterosexual
intercourse must agree to use protocol-specified method(s) of contraception as described in
Appendix 3.

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4.3.
Exclusion Criteria
Patients who meet any of the following exclusion criteria at screening/Day −1 are not eligible to 
be enrolled in this study (no waivers for patient eligibility will be offered or permitted):
1) Mixed small-cell lung cancer and NSCLC histology.
2) Positive serum pregnancy test (Appendix 3) or women who are lactating.
3) Known hypersensitivity to the study drugs, their metabolites, or formulation excipients.
4) Requirement for ongoing therapy with or prior use of any prohibited medications for SG and 
docetaxel as per Sections 5.6.1 and 5.11, respectively.
5) Received a prior anticancer biologic agent within 4 weeks prior to enrollment or have 
received prior chemotherapy, targeted small molecule therapy, or radiation therapy within 
2 weeks prior to enrollment and have not recovered (ie, > Grade 2 is considered not 
recovered) from AEs at the time of study entry. Patients participating in observational studies 
are eligible.
6) Have not recovered (ie, > Grade 2 is considered not recovered) from AEs due to a previously 
administered agent.

Note: Patients with any grade alopecia are an exception to this criterion and will qualify 
for the study.

Note: If patients received major surgery, they must have recovered adequately from the 
toxicity and/or complications from the intervention prior to starting study drug.
7) Previously received treatment with any of the following:
a) Topoisomerase 1 inhibitors. Any agent including an ADC containing a chemotherapeutic 
agent targeting topoisomerase 1
b) Trop-2-targeted therapy
c) Docetaxel as monotherapy or in combination with other agents
8) Active second malignancy

Note: Patients with a history of malignancy that have been completely treated, with no 
evidence of active cancer for 3 years prior to enrollment, or patients with surgically cured 
tumors with low risk of recurrence (eg, nonmelanoma skin cancer, 
histologically-confirmed complete excision of carcinoma in situ, or similar) are allowed 
to enroll.
9) NSCLC that is eligible for definitive local therapy alone.

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10) Clinically severe pulmonary compromise resulting from intercurrent pulmonary illnesses 
including, but not limited to, any underlying pulmonary disorder (ie, pulmonary emboli 
within 3 months of enrollment, severe asthma, severe chronic obstructive pulmonary disease, 
restrictive lung disease, pleural effusion, etc); any autoimmune, connective tissue, or 
inflammatory disorders with pulmonary involvement (ie, rheumatoid arthritis, Sjogren 
syndrome, sarcoidosis, etc); or prior pneumonectomy.
11) Known active central nervous system (CNS) metastases and/or carcinomatous meningitis. 
Patients with previously treated brain metastases may participate provided they have stable 
CNS disease for at least 4 weeks prior to enrollment and all neurologic symptoms have 
returned to baseline, have no evidence of new or enlarging brain metastases, and are taking 
10 mg/day or less of prednisone or its equivalent. All patients with carcinomatous meningitis 
are excluded regardless of clinical stability.
12) Met any of the following criteria for cardiac disease:
a) Myocardial infarction or unstable angina pectoris within 6 months of enrollment.
b) History of serious ventricular arrhythmia (ie, ventricular tachycardia or ventricular 
fibrillation), high-grade atrioventricular block, or other cardiac arrhythmias requiring 
antiarrhythmic medications (except for atrial fibrillation that is well controlled with 
antiarrhythmic medication); history of QT interval prolongation.
c) New York Heart Association Class III or greater congestive heart failure or left 
ventricular ejection fraction of less than 40%.
13) Active chronic inflammatory bowel disease (ulcerative colitis, Crohn’s disease) or 
gastrointestinal perforation within 6 months of enrollment.
14) Active serious infection requiring antibiotics.
15) Positive HIV-1 or HIV-2 antibody with detectable viral load OR taking medications that may 
interfere with SN-38 metabolism.
16) Positive for hepatitis B surface antigen. Patients who test positive for hepatitis B core 
antibody will require hepatitis B virus DNA by quantitative polymerase chain reaction for 
confirmation of active disease. 
17) Positive hepatitis C antibody and detectable hepatitis C viral load.
18) Other concurrent medical or psychiatric conditions that, in the investigator’s opinion, may be 
likely to confound study interpretation or prevent completion of study procedures and 
follow-up examinations.

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5.
STUDY DRUGS
5.1.
Randomization and Treatment Codes Access
Patients who meet randomization eligibility criteria will be randomized in a 1:1 ratio to receive 
either SG or docetaxel starting on Day 1 and assigned a patient number. Randomization will be 
stratified by the following:
1) Histology (squamous vs nonsquamous)
2) Response to last prior immune therapy received (best response PD/SD vs CR/PR on immune 
therapy)
3) Received prior therapy for actionable genomic alteration (yes vs no)
This is an open-label study. Treatment assignment data may be restricted to members of the 
sponsor team in accordance with sponsor processes for data handling. 
5.2.
Description and Handling of Sacituzumab Govitecan
5.2.1.
Formulation
Sacituzumab govitecan is supplied as a sterile, off-white to yellowish lyophilized powder in 
single-dose glass vials. It is formulated in 2-(N-morpholino) ethane sulfonic acid buffer 
containing trehalose and polysorbate 80 and contains no preservatives. Following reconstitution, 
the concentration of SG is 10 mg/mL. The pH of the reconstituted solution is approximately 6.5.
5.2.2.
Packaging and Labeling
Sacituzumab govitecan is packaged in single-use, 50R, glass vials, closed with coated 
elastomeric stoppers and capped with flip-off caps with aluminum over seals.
Study drug to be distributed to centers in the US and other participating countries shall be labeled 
to meet applicable requirements of the US 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
The glass vials of SG must be stored under refrigeration (2-8 °C) and protected from light until 
use. Since the formulated drug product contains no preservative, vials should be used only once. 
After reconstitution, the infusion should be initiated as soon as possible. 
Refer to the current version of the Pharmacy Manual for additional details.

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5.3.
Premedication and Prophylaxis for Sacituzumab Govitecan
Guidance for premedication for prevention of toxicities associated with SG is presented in 
Table 2.
Table 2.
Guidance for Premedication and Prophylaxis for Toxicities 
Associated With Sacituzumab Govitecan
Potential Reaction
Premedication and Prophylaxis Guidance
Infusion-related reaction

Antipyretics and H1/H2 blockers should be administered before each SG 
infusion.

Corticosteroids (hydrocortisone 50 mg or equivalent PO or IV) may be 
administered prior to infusions.
Nausea and vomiting

Premedication with a 2-drug antiemetic regimen is recommended.

If nausea and vomiting are persistent, a 3-drug regimen may be used, including 
a 5-HT3 inhibitor (ondansetron or palonosetron, or other agents according to 
local practices), an NK1-receptor antagonist (fosaprepitant or aprepitant), and 
dexamethasone (10 mg PO or IV).

Anticipatory nausea can be treated with olanzapine.
Neutropenia

Complete blood counts must be obtained prior to each SG infusion and 
treatment should be administered only if ANC meets the following criteria:

Day 1: ANC ≥ 1500/mm3

Day 8: ANC ≥ 1000/mm3

The routine prophylactic use of growth factors is not required; however, 
prophylactic administration should comply with current ASCO/ESMO 
guidelines for use of growth factors. 
ANC = absolute neutrophil count; ASCO = American Society of Clinical Oncology; ESMO = European Society for Medical 
Oncology; IV = intravenous; PO = orally; SG = sacituzumab govitecan
All patients should be given medications to take home with clear instructions for the prevention 
and treatment of nausea, vomiting, and diarrhea. At the onset of diarrhea, promptly initiate 
treatment with antidiarrheals (eg, loperamide at 4 mg initially followed by an additional 2 mg 
with every episode of diarrhea for a maximum of 16 mg daily or follow local label guidelines for 
loperamide). Discontinue antidiarrheals 12 hours after diarrhea resolves. Additional supportive 
measures (eg, fluid and electrolyte substitution) may also be employed as clinically indicated. 
Patients who exhibit an excessive cholinergic response to treatment with SG (eg, abdominal 
cramping, diarrhea, salivation, etc) can receive appropriate premedication (eg, anticholinergics 
such as atropine) for subsequent infusions.
5.4.
Dosage and Administration of Sacituzumab Govitecan
Sacituzumab govitecan is administered at 10 mg/kg as an intravenous (IV) infusion on Days 1 
and 8 of a 21-day cycle.

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The dose of SG will be calculated based on actual weight at enrollment (using weight obtained 
either at screening or on Cycle 1 Day 1) and remains constant throughout the study, unless there 
is a > 10% change in body weight from baseline. Modifications to the study treatment doses 
administered should be made for a > 10% change in body weight from baseline. Dose 
modifications for changes in body weight < 10% may be made according to local institutional 
guidelines.
Sacituzumab govitecan is administered via IV infusion as described below with additional 
information available in the current version of Pharmacy Manual. Sacituzumab govitecan should 
not be administered as an IV push or bolus. Sacituzumab govitecan is a cytotoxic drug and 
applicable special handling and disposal procedures should be followed.

Administer the first infusion over 3 hours. Subsequent infusions may be administered over 
1 to 2 hours if previous infusions were well tolerated. Monitor the patient during, and for at 
least 30 minutes after infusion.

Protect the infusion bag from light.

An infusion pump may be used.

Confirm compatibility with polypropylene infusion bags.

In-line filters and other ancillary infusion equipment are not recommended for use.

Do not mix SG, or administer as an infusion, with other medicinal products.

Upon completion of the infusion, flush the IV line with 20 mL 0.9% Sodium Chloride 
Injection, United States Pharmacopeia.
5.5.
Dose Modification and Treatment Delays of Sacituzumab Govitecan
The major toxicities of SG are expected to be gastrointestinal symptoms and neutropenia. 
Premedication and prophylaxis for the prevention of SG-associated toxicities is described in 
Section 5.3. Management of toxicities should be in accordance with best clinical practices, 
standard institutional guidelines, and current American Society of Clinical Oncology/European 
Society for Medical Oncology guidelines. All patients will be closely monitored over the course 
of their treatment and aggressively medically managed, including dose reduction and 
interruption, to prevent the need for treatment discontinuation and serious complications of these 
toxicities. In particular, patients with known reduced UGT1A1 activity should be closely 
monitored for adverse reactions (see Section 1.2.3.1). All efforts to avoid dose reduction should 
be taken to address toxicity prior to initiation of dose reduction. Instructions for dose 
modification and discontinuation of SG for treatment-related toxicities are provided 
in Section 5.5.1 and instructions for treatment delays are provided in Section 5.5.2.

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5.5.1.
Dose Reductions and Discontinuation of Sacituzumab Govitecan
Table 3 summarizes recommendations for SG dose reductions and discontinuations for 
treatment-related toxicities.
Sacituzumab govitecan dose reductions and interruptions will be managed based on toxicity 
severity. Leukopenia or lymphopenia in the absence of neutropenia does not require dose 
modification. The SG dose must not be re-escalated following a dose reduction.
The SG treatment must be discontinued if there is a 3-week dose delay from the planned 
treatment date due to treatment-related toxicity or 5-week dose delay for all other reasons.
Table 3.
Recommended Dose Modification Schedule for Sacituzumab 
Govitecan
Adverse Reaction
Occurrence
Dose Modification or Action
Severe neutropenia 
First
25% dose reduction and 
administer G-CSF
Second
50% dose reduction
Grade 4 neutropenia ≥ 7 days,
OR
Grade 3-4 febrile neutropenia,
OR
At time of scheduled treatment, Grade 3 or 4 neutropenia that 
delays dosing by 2 or 3 weeks for recovery to ≤ Grade 1
Third
Discontinue Treatment 
At time of scheduled treatment, Grade 3 or 4 neutropenia that 
delays dosing beyond 3 weeks for recovery to ≤ Grade 1
First
Discontinue treatment
Severe nonneutropenic toxicity
First
25% dose reduction
Second
50% dose reduction
Grade 4 nonhematologic toxicity of any duration,
OR
Any Grade 3 or 4 nausea, vomiting, or diarrhea due to 
treatment that is not controlled with antiemetics and 
antidiarrheal agents
OR
Other Grade 3 or 4 nonhematologic toxicity persisting 
> 48 hours despite optimal medical management,
OR
At time of scheduled treatment, Grade 3 or 4 nonneutropenic 
hematologic or nonhematologic toxicity that delays dose by 2 
or 3 weeks for recovery to ≤ Grade 1
Third
Discontinue treatment
In the event of Grade 3 or 4 nonneutropenic hematologic or 
nonhematologic toxicity that does not recover to ≤ Grade 1 
within 3 weeks 
First
Discontinue treatment
Infusion-related toxicities
Grade 2 or Grade 3 infusion-related reaction despite optimal 
management
Recurrent
Discontinue treatment
Grade 4 infusion-related reaction
First
Discontinue treatment
G-CSF = granulocyte-colony stimulating factor; NCI-CTCAE = National Cancer Institute-Common Terminology Criteria for 
Adverse Events
Refer to Section 7 for the NCI-CTCAE severity grading details.

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5.5.2.
Treatment Delays of Sacituzumab Govitecan
Sacituzumab govitecan will be administered in 21-day cycles on Days 1 and 8; the next cycle 
should start a minimum 14 days after the Day 8 dose (ie, the Day 8 infusion will be counted as 
the first day of that 14-day period). However, visit windows of 1 day prior to and 2 days after the 
scheduled infusion are permitted. The scheduled Day 1 and Day 8 infusions may be delayed for 
up to 3 weeks for treatment-related toxicities.
Instructions for dose delays and dose reductions for specific toxicities are summarized below. 
See Table 2 for when SG can be administered based on absolute neutrophil count. Withhold SG 
for Grade 3 nausea or Grade 3 or 4 diarrhea or vomiting at the time of scheduled treatment 
administration and resume dosing when resolved to Grade 1 or less. For toxicities not 
specifically addressed in Table 2, dosing may be delayed for toxicities higher than Grade 2 for a 
maximum of 3 weeks per investigator assessment. If the toxicity has improved to Grade 2 or less, 
the dose should be administered at that time. For a toxicity that delays Day 8 dosing, if dosing is 
delayed for more than 1 week, dosing should resume as Day 1 of next cycle to minimize 
treatment gap. Regardless of whether the Day 8 dose is delayed for toxicity, there should be a 
minimum of 14 days between the Day 8 infusion and the Day 1 infusion of the next cycle.
Palliative radiotherapy is permitted. If there is clear evidence of clinical benefit, treatment may 
be continued after completion of palliative radiotherapy. In this case, SG administration should 
be interrupted 1 week before the procedure and reinstated no earlier than 2 weeks after the 
procedure. In the event a patient requires surgery, SG should be interrupted 1 week before the 
procedure if clinically feasible and dosing should be held for 2 weeks after the procedure. Dosing 
may resume thereafter if the patient is clinically stable. Extensive surgical procedures 
(eg, abdominal, cranial surgeries) may require suspension of dosing for 4 weeks to allow for an 
adequate period for healing before dosing may resume. The study medical monitor must approve 
continuation of therapy with SG before resumption of dosing (see Section 3.4.1 for 
discontinuation criteria).
Treatment interruptions for reasons other than resolution of toxicities/procedures are not 
permitted outside of the permitted visit windows. Refer to Appendix 2 for further details on the 
risks and risk mitigation strategy for study drug dose delays as a result of the pandemic.
5.6.
Prior and Concomitant Medications With Sacituzumab Govitecan
Premedication and prophylaxis are permitted while on SG as described in Section 5.3. 
Medications that are excluded are listed in Section 5.6.1. Palliative and/or supportive 
medications, such as pain medications, bone-modifying medications (bisphosphonates or 
denosumab), antiemetics or antidiarrheal medications, transfusions, and growth factor support 
are allowed at the investigator’s discretion. Palliative radiotherapy is permitted; refer to 
Section 6.3.7 for the response assessment details regarding palliative radiotherapy allowed in this 
study.

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5.6.1.
Prior and Concomitant Medications That are Prohibited or Used With 
Caution With Sacituzumab Govitecan
No anticancer therapies, aside from the study drugs, are permitted during this study.
SN-38 (the active metabolite of SG) is metabolized via human UGT1A1. Concomitant 
administration of strong inhibitors or inducers of UGT1A1, with SG, should be avoided because 
of the potential to either increase (inhibitors) or decrease (inducers) the exposure to SN-38.
For details on the risk and mitigation strategy for concurrent administration of the coronavirus 
disease 2019 vaccine, refer to Appendix 2.
5.6.1.1.
UGT1A1 Inhibitors
Coadministration of SG with inhibitors of UGT1A1 may increase systemic exposure to the 
active metabolite, SN-38. UGT1A1 inhibitors should not be administered concomitantly with SG 
unless there are no therapeutic alternatives. A list of example UGT1A1 inhibitors is provided in 
Appendix 7.
5.6.1.2.
UGT1A1 Inducers
Exposure to SN-38 may be substantially reduced in patients concomitantly receiving UGT1A1 
enzyme inducers. UGT1A1 inducers should not be administered concomitantly with SG unless 
there are no therapeutic alternatives. A list of example UGT1A1 inducers is provided in 
Appendix 7.
Should patients have a need to initiate treatment with any prohibited concomitant medication, the 
Gilead medical monitor must be consulted, and approval granted before initiation of the new 
medication. In instances where a prohibited medication is initiated before discussion with the 
Gilead medical monitor, the investigator must notify Gilead as soon as he/she is aware of the use 
of the prohibited medication.
5.7.
Description and Handling of Docetaxel
5.7.1.
Formulation
Docetaxel is commercially sourced. Information regarding the formulation can be found in the 
current full prescribing information or summary of product characteristics for each country 
where the study will be conducted.
5.7.2.
Packaging and Labeling
Commercial product of docetaxel will be used for this study where docetaxel is approved for the 
treatment of locally advanced or metastatic NSCLC after platinum therapy failure. Study drug to 
be distributed to centers in other participating countries shall be labeled to meet applicable 
requirements of the US FDA, EU Guideline to Good Manufacturing Practice–Annex 13 
(Investigational Medicinal Products), and/or other local regulations.

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5.7.3.
Storage and Handling
Docetaxel is commercially sourced. Information regarding the storage and handling can be found 
in the current prescribing information.
5.8.
Premedication and Prophylaxis for Docetaxel
For docetaxel treatment, patients should be premedicated with oral corticosteroids such as 
dexamethasone 16 mg per day (eg, 8 mg twice daily) for 3 days starting 1 day before docetaxel 
administration to reduce the incidence and severity of fluid retention as well as severity of 
hypersensitivity reactions.
5.9.
Dosage and Administration of Docetaxel
The docetaxel dosing regimen is described in Section 3.2.
5.10.
Dose Modification and Treatment Delays for Docetaxel
Docetaxel is known to cause neutropenia, hepatotoxicity, peripheral neuropathy, fluid retention, 
and hypersensitivity reactions. Patients with pre-existing effusions should be closely monitored 
from the first dose for the possible exacerbation of the effusions. Patients developing peripheral 
edema may be treated with standard measures (eg, salt restriction, oral diuretics).
Docetaxel dose delays and resumption of treatment as well as dose reductions and treatment 
discontinuation decisions should be conducted in accordance with the current local docetaxel 
label and treatment guidelines. The docetaxel dose must not be re-escalated following a dose 
reduction.
Recommended initial dose and dose reductions for docetaxel:

Initial dose: 75 mg/m2

First dose level reduction: 55 or 60 mg/m2 (as per local label and guidelines for docetaxel)

Second dose level reduction: Per investigator’s discretion (as per local label and guidelines 
for docetaxel)
Docetaxel should not be administered to patients who have significant liver dysfunction or a 
neutrophil count of less than 1500 cells/mm3 (refer to local label for liver function requirements 
for dosage and dose modification for hematologic toxicities).
Patients who are dosed initially at 75 mg/m2 and who experience either febrile neutropenia, 
neutrophils less than 500 cells/mm3 for more than 1 week, severe or cumulative cutaneous 
reactions, or other Grade 3/4 nonhematologic toxicities during docetaxel treatment should have 
treatment withheld until resolution of the toxicity and then resume dosing at the next dose level 
reduction.

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Criteria for permanent discontinuation of docetaxel

Grade 3 or higher peripheral neuropathy

Cystoid macular edema

Severe hypersensitivity reaction to docetaxel

Consider discontinuation for severe cutaneous AEs (eg, Stevens Johnson syndrome)
Docetaxel treatment must be discontinued if there is more than a 5-week dose delay from the 
last dose or failure to resolve a toxicity within 3 weeks of the last dose of docetaxel.
5.11.
Prior and Concomitant Medications With Docetaxel
The current local docetaxel prescribing information should be followed for permitted and 
prohibited concomitant medications.
5.12.
Accountability for Study Drugs
The investigator is responsible for ensuring adequate accountability of all used and unused study 
drug vials. This includes acknowledgment of receipt of each shipment of study drug (quantity 
and condition).
Each study site must keep accountability records that capture:

The date received, quantity, and condition of study drug vials

The date, patient number, and the study drug quantity or medication number dispensed.

The date, quantity of used and unused study drug vials returned, along with the initials of the 
person recording the information
5.12.1.
Study Drug Return or Disposal
Gilead recommends that used and unused study drug supplies be destroyed at the site. If the site 
has an appropriate standard operating procedure for drug destruction as determined by Gilead, 
the site may destroy used (empty or partially empty) and unused study drug supplies in 
accordance with that site’s approved procedural documents. A copy of the site’s approved 
procedural document will be obtained for the electronic trial master file. If study drug is 
destroyed at the site, the investigator must maintain accurate records for all study drugs 
destroyed. Records must show the identification and quantity of each unit destroyed, the method 
of destruction, and the person who disposed of the study drug. Upon study completion, copies of 
the study drug accountability records must be filed at the site. Another copy will be provided to 
Gilead.
If the site does not have an appropriate standard operating procedure for drug destruction, used 
and unused study drug supplies are to be sent to the designated disposal facility for destruction. 
The study monitor will provide instructions for return.
The study monitor will review study drug supplies and associated records at periodic intervals.

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6.
STUDY PROCEDURES
The study procedures to be conducted for each patient screened or enrolled in the study are 
presented in tabular form in Table 1 and described in the sections below.
The investigator must document any deviation from the protocol procedures and notify Gilead or 
the contract research organization.
6.1.
Informed Consent
The investigator is responsible for obtaining written informed consent from each patient 
participating in this study after adequate explanation of the rationale, methods, objectives, and 
potential hazards of the study before undertaking any study-related procedures. The informed 
consent form (ICF) will inform patients about genomic testing and/or planned sample retention. 
In addition to the study-specific ICF to be signed by each patient participating in the study, 
patients will be required to document agreement to provide additional samples or to allow the 
use of the remainder of their already-collected specimens for optional future research in 
accordance with applicable regulations. In addition to the study-specific ICF to be signed by 
each patient participating in the study, patients will be required to document agreement to 
provide additional samples and/or to allow the use of the existing samples for optional genomic 
research. The results of the tests performed on the samples will not be given to the patient or the 
investigator.
6.2.
Screening, Patient Enrollment, and Treatment Assignment
Patients will be screened within 28 days prior to enrollment to determine eligibility for 
participation in the study. Patients meeting all of the inclusion criteria and none of the exclusion 
criteria will return to the study site within 28 days after screening for enrollment into the study. 
Enrollment occurs upon receipt of randomization number via IRT. Randomization must occur on 
or before Cycle 1 Day 1. Dosing must commence within 3 days after randomization.
No waivers for patient eligibility will be offered or permitted.
Patient screening laboratory assessments may be repeated beyond the initial screening 
assessments within the 28-day screening period.
Patients who fail to meet eligibility criteria may be rescreened once if there is a reasonable 
expectation that the patient will meet eligibility after repeat screening. Entry into screening does 
not guarantee enrollment into the study. 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.

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6.3.
Instructions for Study Procedures
Study procedures, including instructions for standard procedures (eg, medical history, physical 
examination, vital signs) are presented in Table 1. Assessments requiring additional detail are 
presented below.
6.3.1.
Adverse Events
From the time informed consent is obtained through the first dose of study drug, record all SAEs, 
as well as any AEs related to protocol-required procedures on the AE electronic case report form 
(eCRF). All untoward medical occurrences observed during the screening period, including 
exacerbation or changes in medical history, are to be considered medical history. After the first 
dose of study drug, report all AEs and SAEs. See Section 7 for additional details.
6.3.2.
Prior and Concomitant Medications
Medications administered prior to the first dose of study drug will be recorded as prior 
medications, whereas medications initiated after administration of the first dose of study drug 
until 30 days after treatment discontinuation will be captured as concomitant medications. 
Medication information will be entered in the appropriate eCRF with information regarding 
dose, indication, route of administration, and dates of administration. Medications used for 
prophylaxis of anticipated study drug AEs as outlined in the protocol should be documented 
along with the rationale for prophylactic intent.
Additional information regarding concomitant medications is located in Sections 5.6 and 5.11.
6.3.3.
Vital Signs
Vital signs will be recorded according to the study procedures table (Table 1). Additional 
collection of vital signs will be needed in the event of suspected infusion-related reactions. Vital 
signs will include blood pressure, pulse, respiratory rate, and body temperature and will be 
recorded after the patient has been resting for at least 5 minutes.
6.3.4.
Electrocardiograms
Local 12-lead ECGs will be obtained for all patients according to the study procedures table 
(Table 1). Abnormal findings should be evaluated as clinically indicated, including repeated 
ECGs. ECGs may be performed at other time points during the study if clinically indicated.
ECGs are to be performed at rest in the supine position. Clinically significant abnormal findings 
should be noted and the appropriate clinical work-up initiated until the condition has stabilized.
The following will be measured or calculated: heart rate, PR, QRS, QT, QTcF, and rhythm.

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6.3.5.
Clinical Laboratory Assessments
All clinical laboratory samples for safety are required to be collected and analyzed by a central 
laboratory at screening and every subsequent study visit (per Table 1) with appropriate clinical 
action taken based on the investigator’s clinical judgment. Local laboratory test results may be 
used in addition to central laboratory tests for immediate clinical decisions. Eligibility 
determination is based on the central laboratory test results. All investigations will be assessed 
for all patients according to the study procedures table (Table 1). Additional and more frequent 
tests may be performed at the investigator’s discretion. Clinically significant abnormal results 
should be repeated within 24 to 48 hours to confirm abnormality and followed until resolution. 
Results of unscheduled tests should be documented. The panels of laboratory tests to be 
performed are shown in Table 4.
Table 4.
Laboratory Tests
Safety Laboratory Measurements
Serum Chemistry
Hematology
Coagulation
Urinalysis
Other Laboratory 
Measurements
Albumin
ALP
ALT
AST
Bicarbonate 
(CO2/HCO3-)
Urea nitrogen
Calcium
Chloride
Creatinine
Glucose
Magnesium
Phosphorus
Potassium
Sodium
Total bilirubin
Total protein
Hemoglobin
Platelet count
WBC count and 
differential with 
(ANC)
INR
PT
PTT
Blood
Glucose
pH
Protein
Ketones
FSHa
LDHb
Pregnancy testc
Uric acidb
HBV surface antigen
HBV core antibody
HBV DNA, as 
applicabled
HCV antibody
HCV RNA, as 
applicablee
HIV-1 antibody
HIV-2 antibody 
HIV RNA, as 
applicablef
ALP = alkaline phosphatase; ALT = alanine aminotransferase; ANC = absolute neutrophil count; AST = aspartate 
aminotransferase; HBV = hepatitis B virus; HCV = hepatitis C virus; INR = international normalized ratio; PT = prothrombin 
time; PTT = partial thromboplastin time; RBC = red blood cell; WBC = white blood cell
Refer to Table 1 for collection time points.
a
Conduct as needed per Appendix 3 for determination of childbearing potential.
b
May be tested more frequently at the discretion of the managing physician if abnormal results warrant follow-up. Results of 
unscheduled tests should be documented.
c
In female patients of childbearing potential, pregnancy testing will be performed according to the study procedures table 
(Table 1) and as discussed in Appendix 3.
d
Perform HBV DNA testing if the patient tests positive for HBV core antibody.
e
Perform HCV RNA testing if the patient tests positive for HCV antibody.
f
Perform HIV RNA testing if the patient tests positive for HIV-1 antibody or HIV-2 antibody.

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6.3.6.
ECOG Performance Status
Eastern Cooperative Oncology Group performance status will be assessed according to the study 
procedures table (Table 1). Appendix 5 presents the performance status criteria.
6.3.7.
Efficacy Assessments
Computed tomography or MRI scans with IV contrast (unless contrast use is medically 
contraindicated) of chest, abdomen, pelvis, and any other involved disease sites are required in 
all patients at screening and every 6 weeks for first 12 months, and then every 9 weeks from the 
date of randomization until the occurrence of radiologic PD per RECIST Version 1.1 criteria 
requiring discontinuation of further treatment. Patients with known brain metastasis must have a 
brain MRI. For each patient, the same imaging technique should be used throughout the study for 
tumor assessment. Patients who discontinue treatment due to toxicity or for any reason other than 
objective progression will continue to obtain radiologic response assessments according to the 
protocol-required schedule until radiologic PD or initiation of subsequent anticancer therapy. 
Visit windows are ± 7 days for imaging (Table 1). The timing of imaging is based on calendar 
time from the date of randomization. Dose delays and cycle delays should not result in delays in 
the timing of imaging.
If the use of IV contrast is medically contraindicated for a patient, 1 of following options may be 
used (listed in order of preference): CT without contrast, MRI without contrast, or attempt to 
desensitize the patient with steroids.
Target and nontarget lesions must be determined by the clinical site at baseline according to the 
RECIST Version 1.1 criteria (Appendix 6). Clinical progression leading to patient 
discontinuation should be documented by CT or MRI scan of target lesions if clinically feasible. 
Patients who discontinue treatment due to toxicity or for any reason other than objective 
progression will continue to obtain radiologic response assessments according to the 
protocol-required schedule until radiologic PD or initiation of subsequent anticancer therapy. For 
patients with evidence of CR and PR, a confirmatory scan must be obtained a minimum of 4 to 
6 weeks after initial documentation of response. Additional CT or MRI scans may be performed 
at the discretion of the investigator to assess disease status as medically indicated. These results 
should be recorded. Tumor response and progression will be determined using RECIST 
Version 1.1 (Appendix 6).
If palliative radiotherapy is given (Section 5.6), the presence of new or worsening metastases 
will be considered progression. Palliative radiation of a target lesion will render that target lesion 
and subsequent tumor assessments “not evaluable” and should be avoided. If the radiologic 
assessment does not confirm PD, patients should continue to be assessed per the study 
procedures table.
If a patient has known or suspected bone metastasis, a bone scan (99m-technetium 
polyphosphonate scintigraphy, whole body bone MRI, or 18F-NaF/fluorodeoxyglucose [18F] 
[FDG] positron emission tomography [PET]) to assess bone metastases will be performed 
according to the study procedures table (Table 1). In patients whose body CT/MRI scans indicate 

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that CR has been achieved, a bone scan or 18F-NaF/FDG PET will be required at confirmation 
of CR to exclude the presence of new bone metastases or if clinically indicated, and will occur 
within 1 week, but not more than 2 weeks following a CR as assessed by the investigator. For 
each patient, the same imaging technique used at screening should be used throughout the study 
to ensure comparability. Lesions detected on bone scans must be followed with cross-sectional 
imaging.
All radiology images and reports for screening, response, and progression will be provided to the 
central imaging vendor and held for potential further blinded independent central review based 
upon regulatory feedback or at the sponsor’s discretion.
6.3.8.
Pharmacokinetics
Serum samples for PK analysis will be collected from all patients who receive SG according to 
the study procedures table (Table 1). Following PK analytes will be measured at the specified 
time points: SG, total SN-38, free SN-38, and total antibody.
6.3.9.
Immunogenicity Assessments
Serum samples for immunogenicity (ADA) analysis will be collected from all patients who 
receive SG according to the study procedures table (Table 1). Serum samples will be evaluated 
using a validated ADA assay. Based on the results from the ADA assay, the samples may be 
assessed using a validated nAb assay, if available.
6.3.10.
Immunohistology Evaluation of Tumor
Preferably, local testing will be conducted according to the study procedures table (Table 1) if 
EGFR, ALK, or PD-L1 status is unknown. If local testing is unavailable, tumor tissue testing can 
be performed by the central laboratory.
See Appendix 9 for United Kingdom and EU specific text.
6.3.11.
UGT1A1 Genotype
UGT1A1 genotype will be evaluated from a blood sample collected according to the study 
procedures table (Table 1).
6.3.12.
Biomarker Testing
6.3.12.1.
Biomarker Samples to Address the Study Objectives
The following biological specimens will be collected from all patients 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 study drug response (including efficacy and/or AEs) and 
dosage selection, and to better understand the biological pathways, biology of NSCLC, and/or 
the validation of a companion diagnostic for SG. 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 performed on the specimens provided. The 
specific analyses will include but may not be limited to the biomarkers and assays listed below. 

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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.
Archival tumor tissue (formalin-fixed, paraffin-embedded [FFPE] block) that was obtained 
preferably within 12 months prior to initial dosing (Cycle 1 Day 1) or newly acquired tumor 
tissues from an evaluable core or excisional biopsy collected from patients within signing of the 
informed consent to prior to initial dosing (Cycle 1 Day 1) may be submitted to the central 
laboratory. Tissue samples older than 12 months are acceptable. If tumor blocks are not 
available, it is recommended to submit freshly-cut unstained slides, sections of 4-5-micron 
thickness, serially cut from a single FFPE block and mounted on positively charged slides. Refer 
to the Laboratory Manual for further details. All efforts should be made to submit tumor tissue to 
the central laboratory. Consult with the sponsor if a sample is unavailable and the patient is 
unwilling to undergo a biopsy procedure. 
Mandatory blood specimen will be collected for the extraction of circulating tumor DNA for 
genomic testing and genotyping to test for polymorphisms of genes that could regulate or be 
involved in the disposition of SG. These samples should be collected at screening and at predose 
on Day 1 of Cycles 2 and 3.
Trop-2 testing on archival/new tissue sample obtained prior to treatment will be performed to 
assess if efficacy varies by Trop-2 expression. 
Biomarkers (in blood and tissue) may include, but are not limited to, protein expression, analyses 
of specific immune and tumor signatures (RNA), as well as tumor mutational burden and 
specific tumor mutations (DNA). Tumor and blood samples will be collected to measure 
biomarkers of response and resistance and better understand molecular attributes predictive of 
SG response in NSCLC. Examples may include, but will not be limited to, Trop-2 expression, 
mutations/gene expression related to the DNA damage repair pathways including TOP1 and 
SLFN11, tumor mutational burden, oncogenic mutations, PD-L1 expression, composition of 
immune subsets in the tumor microenvironment, clearance of circulating tumor DNA, 
pathological features of the tumor, and spatial heterogeneity of Trop-2 expression. Biomarker 
samples will be collected at the time points specified in Table 1.
Some of the samples may not be collected at a site if there are local laws or regulations 
preventing collection or if an IRB/IEC does not approve the collection of the sample.
Samples collected for biomarker assessments will be destroyed no later than 15 years after the 
end of the study or per country requirements (Section 9.1.4).
6.3.12.2.
Biomarker Samples for Optional Future Research
In addition to the study-specific ICF to be signed by each patient participating in the study, 
patients will be required to document agreement to provide additional samples or to allow the 
use of the remainder of their already-collected biomarker and PK specimens and data collected 
on the study for optional future research in accordance with applicable regulations.

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The specimens collected for optional future research in conjunction with collected data may be 
used to advance development of the study drug and/or increase our knowledge and 
understanding of the biology of the disease under investigation and related diseases. These 
specimens may also be used to study the association of biomarkers with biological pathways, 
disease pathogenesis, progression, and/or treatment outcomes, including efficacy, AEs, and the 
processes of drug absorption and disposition. In addition, these specimens may be used to 
develop biomarker and/or diagnostic assays and establish the performance characteristics of 
these assays. The collection and analysis of optional future research specimens may facilitate the 
design of new pharmaceutical agents and the development of diagnostic tests, which may allow 
for individualized drug therapy for patients in the future.
The specimens collected for optional future research will be destroyed no later than 15 years 
after the end of study or per country requirements (Section 9.1.4).
6.3.12.3.
Biomarker Samples for Optional Genomic Research
In addition to the study-specific ICF to be signed by each patient participating in the study, 
patients will be required to document agreement for use of existing and new samples for optional 
genomic research. A single blood sample will also be obtained from patients who agree to 
participate and provide their additional specific consent. The planned genetic analysis sample 
may not be collected at a site if there are local laws or regulations preventing collection or if an 
IRB/IEC does not approve the collection of the sample.
These samples should be collected at the Cycle 1 Day 1 visit before administration of the 
first dose of study drug but may be collected at any time during the study or at a separate 
poststudy visit, if necessary.
The specimens collected for optional genomic research and data collected on the study may be 
used to advance the development of the drug and/or increase our knowledge and understanding 
of the biology of the disease under investigation or related diseases. These specimens may also 
be used to study the association of biomarkers with biological pathways, disease pathogenesis, 
progression, and/or treatment outcomes, including efficacy, AEs, and the processes of drug 
absorption and disposition. These samples may be used as a germline control with the main study 
biomarker samples. In addition, these specimens may be used to develop biomarker and/or 
diagnostic assays and establish the performance characteristics of these assays. The collection 
and analysis of optional genomic research specimens may facilitate the design of new 
pharmaceutical agents and the development of diagnostic tests, which may allow for 
individualized drug therapy for patients in the future.
The samples collected for optional genomic research will be destroyed no later than 15 years 
after the end of study or per country requirements (Section 9.1.4).

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6.3.13.
Quality of Life Assessments
Quality of life assessments will be performed according to the study procedures table (Table 1). 
The QOL assessments will be conducted before other study procedures occur, including study 
drug administration. The following QOL instruments will be completed in the following 
sequence from first to last.

EQ5D3L {EuroQol Research Foundation 2018}

NSCLC Symptom Assessment Questionnaire (NSCLC-SAQ) {Pro Consortium 2021}

European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-
Core 30 Version 3 (EORTC QLQC30 v3) {European Organisation For Research And 
Treatment Of Cancer (EORTC) 2021}

PGIS with a recall period of 7 days

PGIC since the start of the study

PRO-CTCAE item library (mouth/throat sores, abdominal pain, rash, hair loss, itching, 
numbness, and tingling) {National Institutes of Health (NIH) 2021}
6.4.
Assessments for Discontinuation From Study Treatment
If a patient discontinues study drug (see Section 3.4 for discontinuation criteria), every attempt 
should be made to keep the patient in the study and continue to perform the required 
study-related follow-up and procedures. If this is not possible or acceptable to the patient or 
investigator, the patient may be withdrawn from the study. In the absence of PD, scans should 
continue to be performed as described in the study procedures table (Table 1), until PD or 
initiation of subsequent anticancer therapy, whichever is earlier. After development of PD, or the 
initiation of subsequent anticancer therapy, the patient should still be followed for survival.
A patient who discontinues study drug early will be asked to return to the study site 30 days (± 7) 
after the last dose of study drug to attend an EOT visit. See the study procedures table (Table 1) 
for the assessments to be performed at the EOT visit and beyond.
6.5.
Sample Storage
The stored biological samples may be used by Gilead or its research partner for additional testing 
to provide supplemental data to answer questions that relate to the main study. At the end of this 
study, these samples may be retained in storage by Gilead for a period up to 15 years or per 
country requirements. If patients provide additional specific consent for optional future research, 
residual biologic samples may be retained in storage no later than 15 years after the end of the 
study or per country requirements (Section 9.1.4).

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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 patient administered a study drug 
that does not necessarily have a causal relationship with the treatment. An AE can therefore be 
any unfavorable and/or unintended sign, symptom, or disease temporally associated with the use 
of a study drug, whether or not the AE is considered related to the study drug. Adverse events 
may also include pretreatment or posttreatment complications that occur as a result of 
protocol-specified procedures or special situations (Section 7.1.3).
An AE does not include the following:

Medical or surgical procedures such as surgery, endoscopy, tooth extraction, or transfusion. 
The condition that led to the procedure may be an AE and must be reported.

Preexisting diseases, conditions, or laboratory abnormalities present or detected before the 
screening visit that do not worsen.

Situations where an untoward medical occurrence has not occurred (eg, hospitalization for 
elective surgery, social and/or convenience admissions).

Overdose without clinical sequelae (Section 7.1.3).

Any medical condition or clinically significant laboratory abnormality with an onset date 
before the ICF is signed and not related to a protocol-associated procedure is not an AE but 
rather considered to be preexisting and should be documented as medical history.
Preexisting events that increase in severity or change in nature after study drug initiation or 
during or as a consequence of participation in the clinical study will also be considered AEs.
7.1.2.
Serious Adverse Events
An SAE is defined as an event that, at any dose, results in the following:

Death

A life-threatening situation (Note: The term “life-threatening” in the definition of “serious” 
refers to an event in which the patient was at risk of death at the time of the event; it does not 
refer to an event that hypothetically might have caused death if it were more severe.)

In-patient hospitalization or prolongation of existing hospitalization.

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
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 patient or may 
require intervention to prevent 1 of the other outcomes constituting SAEs. Medical and 
scientific judgment must be exercised to determine whether such an event is reportable under 
expedited reporting rules. Examples of medically important events include intensive 
treatment in an emergency room or at home for allergic bronchospasm; blood dyscrasias or 
convulsions that do not result in hospitalization; and development of drug dependency or 
drug abuse.
7.1.2.1.
Protocol-Specific Serious Adverse Event Clarifications
To maintain study integrity, the following events that are assessed as unrelated to study drug will 
not be considered SAEs:

Progression of disease

Deaths related to progression of disease
Disease progression is an efficacy endpoint and should not be reported as an SAE unless 
assessed as related to study drug. Expected disease progression refers to an event that is 
unequivocally related to disease progression and that the clinical course is consistent with what 
would be expected for the patient’s disease. A clinical event in the setting of disease progression 
would be considered an SAE if it could not unequivocally be attributed to or is not consistent 
with expected course of disease progression. Refer to Section 6.3.7 for additional details about 
disease progression.
7.1.3.
Study Drugs and Gilead Concomitant Medications Special Situations 
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 a study drug 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 a study drug by a patient.

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Misuse is defined as any intentional and inappropriate use of a study drug that is not in 
accordance with the protocol instructions or the local prescribing information.
An overdose is defined as an accidental or intentional administration of a quantity of a study 
drug given per administration or cumulatively that is above the maximum recommended dose as 
per protocol or in the product labeling (as it applies to the daily dose of the patient in question). 
In cases of a discrepancy in drug accountability, overdose will be established only when it is 
clear that the patient has taken the excess dose(s). Overdose cannot be established when the 
patient cannot account for the discrepancy, except in cases in which the investigator has reason 
to suspect that the patient has taken the additional dose(s).
Occupational exposure is defined as exposure to a study drug as a result of one’s professional or 
nonprofessional occupation.
Drug interaction is defined as any drug/drug, drug/food, or drug/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 study drug.
Counterfeit or falsified medicine is defined as any study drug with a false representation of 
(a) its identity, (b) its source, or (c) its history.
7.2.
Assessment of Adverse Events and Serious Adverse Events
The investigator or qualified subinvestigator is responsible for assessing AEs and SAEs for 
causality and severity, and for final review and confirmation of accuracy of event information 
and assessments.
7.2.1.
Assessment of Causality for Study Drugs and Procedures
The investigator or qualified subinvestigator is responsible for assessing the relationship to study 
drug using clinical judgment and the following considerations:

No: Evidence exists that the AE has an etiology other than the study drug. For SAEs, an 
alternative causality must be provided (eg, preexisting condition, underlying disease, 
intercurrent illness, concomitant medication).

Yes: There is reasonable possibility that the AE may have been caused by the study drug.
It should be emphasized that ineffective treatment should not be considered as causally related in 
the context of AE reporting.

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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 National Cancer Institute-Common Terminology 
Criteria for Adverse Events (NCI-CTCAE) Version 5.0. For each episode, the highest grade 
attained should be reported as defined in the NCI-CTCAE Toxicity Scale (Appendix 4).
7.3.
Investigator Reporting Requirements and Instructions
7.3.1.
Requirements for Collection Before Study Drug Initiation
After informed consent, but before initiation of study drug, the following types of events must be 
reported on the applicable eCRFs: all SAEs and any AEs that are related to protocol-required 
procedures.
7.3.2.
Adverse Events
Following initiation of study drug, collect all AEs, regardless of cause or relationship, until 
30 days after the last dose of study drug 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 occur after the patient first consents to 
participate in the study (ie, signing the ICF) and throughout the duration of the study, including 
the posttreatment follow-up visit, must be reported on the applicable eCRFs and to Gilead 
Patient Safety as instructed below in this section. This also includes any SAEs resulting from 
protocol-associated procedures performed after the ICF is signed.
Any SAEs (including deaths, see Section 7.1.2.1 for exclusions) that occur up to 30 days after 
the last dose of study drug, regardless of causality, should also be reported.
Investigators are not obligated to actively seek SAEs after the protocol-defined follow-up period; 
however, if the investigator learns of any SAEs that occur after the protocol-defined follow-up 
period has concluded and the event is deemed relevant to the use of study drug, the investigator 
should promptly document and report the event to Gilead Patient Safety.
Instructions for reporting SAEs are described in Section 7.4.1.

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7.3.4.
Study Drug Special Situations Reports
All study drug SSRs that occur from study drug initiation and throughout the duration of the 
study, including the posttreatment follow-up visit, must be reported to Gilead Patient Safety 
(Section 7.4.2). Adverse events and SAEs resulting from SSRs must be reported in accordance 
with the AE and SAE reporting guidance (Section 7.3).
7.3.5.
Concomitant Medications Reports
7.3.5.1.
Gilead Concomitant Medications Special Situations Report
Special situation reports involving a Gilead concomitant medication (not considered study drug), 
that occur after the patient first consents to participate in the study (ie, signing of the ICF) and 
throughout the duration of the study, including the posttreatment follow-up visit, must be 
reported to Gilead Patient Safety utilizing the paper SSR form (Section 7.4.2.2).
7.3.5.2.
Non-Gilead Concomitant Medications Report
Special situations involving non-Gilead concomitant medications do not need to be reported on 
the SSR form; however, for special situations that result in AEs due to a non-Gilead concomitant 
medication, the AE should be reported on the AE eCRF.
Any inappropriate use of concomitant medications prohibited by this protocol should not be 
reported as “misuse,” but may be more appropriately documented as a protocol deviation.
All clinical sequelae in relation to these SSRs will be reported as AEs or SAEs at the same time 
using the AE eCRF and/or the SAE eCRF. Details of the symptoms and signs, clinical 
management, and outcome will be reported, when available.
7.4.
Reporting Process for Serious Adverse Events and Special Situations Reports
7.4.1.
Serious Adverse Event Reporting Process
For fatal or life-threatening events, copies of hospital case reports, autopsy reports, and other 
documents are also to be transmitted by email or fax when requested and applicable. 
Transmission of such documents should occur without personal patient identification, 
maintaining the traceability of a document to the patient 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 patient’s eCRF and the SAE narrative section of the Safety Report 
Form eCRF.

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A spontaneous abortion is always considered to be an SAE and will be reported as described in 
Section 7.4.1. Furthermore, any SAE occurring as an adverse pregnancy outcome after the study 
must be reported to the Gilead Patient Safety.
The patient should receive appropriate monitoring and care until the conclusion of the 
pregnancy. The outcome of the pregnancy/partner pregnancy should be reported to Gilead 
Patient Safety 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 
Gilead Patient Safety. Gilead Patient Safety contact information is as follows: email: 
 and fax: 
Refer to Appendix 3 for Pregnancy Precautions, Definition for Female of Childbearing Potential, 
and Contraceptive Requirements.
7.5.
Gilead Reporting Requirements
Depending on relevant local legislation or regulations, including the applicable US FDA Code of 
Federal Regulations, the EU Clinical Trials Directive (2001/20/EC) and relevant updates, and 
other country-specific legislation or regulations, Gilead may be required to expedite to 
worldwide regulatory agencies reports of SAEs which may be in the form of line listings, serious 
adverse drug reactions, or suspected unexpected serious adverse reactions. In accordance with 
the EU Clinical Trials Directive (2001/20/EC), Gilead or a specified designee will notify 
worldwide regulatory agencies and the relevant IEC in concerned Member States of applicable 
suspected unexpected serious adverse reactions as outlined in current regulations.
Assessment of expectedness for SAEs will be determined by Gilead using reference safety 
information specified in the IB or relevant local label as applicable.
All investigators will receive a safety letter notifying them of relevant suspected unexpected 
serious adverse reaction reports associated with any study drug. The investigator should notify 
the IRB or IEC of suspected unexpected serious adverse reaction reports as soon as is practical, 
where this is required by local regulatory agencies, and in accordance with the local institutional 
policy.
To minimize the possibility of exposing patients to unusual risk, the safety information from this 
study will also be reviewed periodically by an independent DMC. The DMC may have access to 
data and will make recommendations regarding the study according to the DMC charter.
7.6.
Clinical Laboratory Abnormalities and Other Abnormal Assessments as 
Adverse Events or Serious Adverse Events
Laboratory abnormalities without clinical significance are not to be recorded as AEs or SAEs. 
However, laboratory abnormalities (eg, clinical chemistry, hematology, urinalysis) that require 
medical or surgical intervention or lead to study drug interruption, modification, or 
discontinuation must be recorded as an AE, as well as an SAE, if applicable. In addition, 
laboratory or other abnormal assessments (eg, ECG, x-rays, vital signs) that are associated with 
signs and/or symptoms must be recorded as an AE or SAE if they meet the definition of an AE 
or SAE as described in Sections 7.1.1 and 7.1.2. If the laboratory abnormality is part of a 
syndrome, record the syndrome or diagnosis (eg, anemia), not the laboratory result (ie, decreased 
hemoglobin).
PPD
PPD

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Severity should be recorded and graded according to the NCI-CTCAE Version 5.0. 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
The investigator is responsible for monitoring of AEs and laboratory parameters for graded 
toxicities. Refer to Sections 5.5 and 5.10 (Dose Modifications and Treatment Delays of SG and 
docetaxel, respectively).
Management of AEs and laboratory toxicities not covered in Sections 5.5 and 5.10 is at the 
discretion of the investigator. For Grade 3 and 4 toxicities, relationship to study drugs, clinical 
status of patient, and investigator assessment of patient safety should inform patient withdrawal 
from dosing. Abnormal laboratory values should be repeated when necessary and followed until 
resolution and as clinically appropriate. 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 
patients 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 satisfactory explanation for the changes observed.
Any questions regarding toxicity management or management of specific laboratory values 
should be directed to the Gilead medical monitor.

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8.
STATISTICAL CONSIDERATIONS
8.1.
Analysis Objectives and Endpoints
Objectives and endpoints are listed in Section 2.
8.2.
Planned Analyses
8.2.1.
Interim Analyses
There will be 1 planned interim superiority analysis and 1 final analysis based on the primary 
endpoint of OS for this study.
The superiority interim efficacy analysis will be performed when approximately 242 death 
events (72% of the final target OS events) have occurred across the SG and docetaxel treatment 
arms. This is predicted to occur approximately 23 months after the first patient is randomized.
The Lan-DeMets spending function that approximates an O’Brien-Fleming approach will be 
used to account for multiplicity introduced by including an interim analysis for superiority. The 
alpha level applied at the interim depends upon the proportion of information available. If 
242 death events (72% of the target 336 events with 42% maturity) have occurred at the time of 
the analysis, the 1-sided significance level to be applied for the OS at the interim and final 
analysis would be 0.82% and 2.25%.
To ensure the integrity of the study and to oversee the planned efficacy interim analysis, an 
independent DMC will review the interim analysis results and may recommend changes in the 
conduct of the study.
Details of the DMC plan and communication process will be provided in the DMC charter.
8.2.2.
Final Analysis
The final analysis of the primary endpoint of OS will be conducted in the ITT Analysis Set when 
approximately 336 death events have occurred for across the treatment arms of SG versus 
docetaxel (336/580 events with 58% maturity), which is projected for approximately 29 months 
of survival follow-up after the first patient is randomized
8.3.
Analysis Conventions
8.3.1.
Analysis Sets
8.3.1.1.
Efficacy
The ITT Analysis Set will include all randomized patients according to the treatment arm to 
which the patient is randomized, unless otherwise specified. This is the primary analysis set for 
all efficacy analyses.

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8.3.1.2.
Safety
The Safety Analysis Set will include all patients who received at least 1 dose of any study drug, 
with treatment assignments designated according to the actual treatment received. This is the 
primary analysis set for all safety analyses.
8.3.1.3.
Pharmacokinetics
The PK analysis will be conducted on Pharmacokinetic Analysis Set, defined as all randomized 
patients who received at least 1 dose of SG per the protocol and have at least 1 measurable 
posttreatment serum concentration of SG.
8.3.1.4.
Immunogenicity
The immunogenicity analysis will be conducted on Immunogenicity Analysis Set, defined as all 
randomized patients who received at least 1 dose of SG and have at least 1 evaluable 
posttreatment anti-SG antibody test result.
8.3.1.5.
Biomarkers
The biomarker analysis will be conducted on the Biomarker Analysis Set, defined as all patients 
who received any study drug and have at least 1 evaluable posttreatment biomarker measurement 
available.
8.3.1.6.
Quality of Life Assessments
Quality of life assessments will be analyzed for patients in the ITT Analysis Set.
8.3.2.
Data Handling Conventions
By-patient listings will be created for important variables from each eCRF module. Summary 
tables for continuous variables will contain the following statistics: N (number in analysis set), n 
(number with data), mean, standard deviation, 95% CIs on the mean, median, minimum, and 
maximum. Summary tables for categorical variables will include N, n, percentage, and 95% CIs 
on the percentage. Unless otherwise indicated, 95% CIs for binary variables will be calculated 
using the binomial distribution (exact method) and will be 2-sided.
Data will be described and summarized by treatment arm. The baseline value used in each 
analysis will be the last (most recent) pretreatment value before or on the first dosing date of 
study drug. As appropriate, changes from baseline to each subsequent time point will be 
described and summarized. Similarly, as appropriate, the best change from baseline during the 
study will also be described and summarized. Graphical techniques (ie, waterfall plots, 
Kaplan-Meier curves, and line plots) may be used when such methods are appropriate and 
informative. Analyses will be based upon the observed data unless methods for handling missing 
data are specified. If there is a significant degree of non-normality, analyses may be performed 
on log-transformed data or nonparametric tests may be applied, as appropriate.

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8.4.
Demographic and Baseline Characteristics Analysis
Demographic and baseline characteristics will be summarized using standard descriptive 
methods by treatment arm. Categorical variables will be summarized by number and percentage. 
Continuous variables will be summarized using number of patients, mean, standard deviation, 
median, and range (minimum and maximum), unless otherwise specified. Details will be 
provided in the SAP.
8.5.
Efficacy Analysis
8.5.1.
Primary Analysis
The primary analysis of OS for comparing SG versus docetaxel will be performed in the ITT 
Analysis Set using the log-rank test stratified by randomization stratification factors (see 
Section 5.1). The HR and its 95% CI estimated using a Cox proportional hazard regression 
model stratified by randomization stratification factors will also be presented. Overall survival 
will be summarized by treatment arm using Kaplan-Meier estimates, which will include median 
and the proportion of patients alive at benchmark time points such as 12 and 18 months. 
Kaplan-Meier plots will be provided.
8.5.2.
Secondary Analyses
At the time of the OS interim analysis, PFS, ORR, and other secondary endpoints will be mature 
for the final analysis, which will be approximately 23 months after the first patient is 
randomized.
The secondary endpoint PFS assessed by the investigator per RECIST Version 1.1 will be 
performed using the same methods as described for the primary OS analysis. Patients who have 
not progressed or died at the time of analysis will be censored according to the censoring rules 
similar to those described in the US FDA Guidance for Industry Clinical Trial Endpoints for the 
Approval of NSCLC Drugs and Biologics {U.S. Department of Health and Human Services 
(DHHS) 2015}. The detailed PFS censoring rules will be described in the SAP.
The ORR will be based on RECIST Version 1.1 using investigator-assessed response data. The 
ORR will be analyzed and compared between the treatment arms using the Cochran 
Mantel-Haenszel test stratified by the stratification factors used for randomization. The 2-sided 
95% CIs for each treatment will be calculated using the Clopper-Pearson exact method.
Kaplan-Meier estimates of median DOR and its 95% CI will be calculated for responders (CR or 
PR) in each treatment arm. 
Disease control rate will be analyzed using the same methods as described for ORR.
8.5.2.1.
Quality of Life Analyses
The NSCLC-SAQ instrument will generate scores for 5 domains and a total score for each 
assessment visit. The analysis of time to first symptom deterioration in NSCLC-SAQ total score 
and time to first deterioration in NSCLC-SAQ shortness of breath domain will be conducted 
between the 2 treatment groups using the log-rank test stratified by randomization stratification 
factors in the ITT Analysis Set. 

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8.5.3.
Exploratory Analyses
The analysis of the exploratory QOL endpoints will include the following:

Mean change from baseline of total score and all domains of NSCLC-SAQ not assessed as 
secondary endpoints.

Mean change from baseline of all domains of EORTC QLQ-C30 v3.

The proportion of patients with meaningful change in each QOL domain while on treatment 
will be assessed in between-treatment comparisons.

Time to first improvement and time to first deterioration in each QOL domain not assessed as 
secondary endpoints will be assessed in between-treatment comparisons.

PRO-CTCAE scores for each attribute (frequency, severity, or interference) will be assessed 
in between-treatment comparisons.

Further details for the exploratory QOL endpoints analyses will be outlined in the SAP.
8.6.
Safety Analysis
Safety analyses will be performed using the Safety Analysis Set. Safety data will be summarized 
by treatment arm using descriptive statistics for TEAEs, clinical laboratory tests, vital signs, and 
concomitant medications. Information regarding study drug administration, study drug 
compliance, and other safety variables will also be summarized descriptively by treatment arm.
8.6.1.
Extent of Exposure
A patient’s extent of exposure to study drug data will be generated from the study drug 
administration data. Exposure data will be summarized by treatment arm.
8.6.2.
Adverse Events
Clinical and laboratory AEs will be coded using the current version of the Medical Dictionary 
for Regulatory Activities. System organ class, high-level group term, high-level term, preferred 
term, 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 study drug through 
30 days after the last dose of study drug.
Summaries (number and percentage of patients) of treatment-emergent AEs (by system organ 
class and preferred term) will be provided by treatment arm.

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8.6.3.
Laboratory Evaluations
Selected laboratory test data (using conventional units) will be summarized using only observed 
data. Data and change from baseline at all scheduled time points will be summarized by 
treatment arm.
Graded laboratory abnormalities will be defined according to NCI-CTCAE Version 5.0 
(Appendix 4).
Incidence of treatment-emergent laboratory abnormalities, defined as values that increase at least 
1 toxicity grade from baseline at any time point postbaseline will be summarized by treatment 
arm. If baseline data are missing, then any graded abnormality (ie, at least a Grade 1) will be 
considered treatment-emergent.
Laboratory abnormalities that occur before the first dose of study drug through 30 days after the 
last dose of study drug will be included in a data listing.
8.6.4.
Other Safety Evaluations
Vital signs, ECOG performance status, and concomitant medications will be summarized by 
treatment arm. Physical examination findings may be provided in a listing.
8.7.
Adjustments for Multiplicity
The overall Type I error rate for this study is strictly controlled at a 1-sided alpha of 2.5%. A 
Lan-DeMets alpha spending function that approximates an O’Brien-Fleming approach will be 
used to account for multiplicity introduced by including an interim analysis for superiority. The 
OS efficacy interim analysis will be tested at the 1-sided significance level of 0.82% if 72% of 
the death events (242/336) is available at the time of the analysis. If the OS interim analysis is 
not positive, the OS final analysis will be tested at the 1-sided significance level of 2.25%. Note 
that alpha levels for the OS interim and final analysis are based on the actual observed events 
and will be adjusted accordingly.
If the primary OS analysis is positive at either interim or final, the final analysis based on the full 
dataset of the key secondary efficacy endpoints of PFS, ORR, time to first deterioration in 
shortness of breath, and time to first deterioration in NSCLC-SAQ total score, as measured by 
NSCLC-SAQ will be formally tested sequentially at the 1-sided alpha of 2.5% when the above 
hypotheses in the hierarchy were also statistically significant (Figure 2). All of the secondary 
efficacy endpoints will be mature and the final analysis could be performed at the time of the OS 
interim analysis.

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Figure 2.
Hierarchical Testing Procedures
FA = final analysis; IA = interim analysis; ITT = intent to treat; NSCLC-SAQ = non-small cell lung cancer Symptom Assessment 
Questionnaire; ORR = objective response rate; OS = overall survival; PFS = progression-free survival
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
 
 
 
 
 
 
 
 
 
 
  
 
 
 
 
  
 
 
  
  
 
 
 
 
 
 
 
 
 
 

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8.8.
Pharmacokinetic Analysis
Serum samples for PK analysis will be collected for patients who receive SG. Plasma 
concentrations and PK parameters (ie, Cmax, Ctrough) will be listed and summarized for SG, total 
SN-38, free SN-38, and total antibody using descriptive statistics.
8.9.
Immunogenicity Analysis
Serum samples for ADA analysis will be collected for patients who receive SG. The impact of 
immunogenicity, if detected, will be evaluated in relation to PK and clinical responses, 
safety/tolerability, and efficacy.
8.10.
Biomarker Analysis
Baseline Trop-2 analysis will be performed and correlated with clinical outcomes. The baseline 
level, absolute level, and change from baseline level over time will be summarized using 
descriptive statistics for each biomarker at the sample collection time point by treatment arm, as 
appropriate. Exploratory analyses may be performed to evaluate the association of each 
biomarker or combination of biomarkers with clinical outcomes.
8.11.
Sample Size
Global Study
Approximately 580 eligible patients will be randomly assigned in a 1:1 ratio to receive either SG 
or docetaxel over a planned nonuniform accrual period of 19 months.
The sample size is estimated based on the primary endpoint of OS. The assumed OS treatment 
effect under the alternative hypothesis is an average HR of 0.70 for SG versus docetaxel, which 
is characterized by a median OS of 11 months on docetaxel treatment {Paz-Ares 2021} {Fossella 
2002}and a median OS of 15.7 months on SG treatment assuming OS is exponentially 
distributed. A total of 336 death events are required to detect a statistically significant difference 
at overall 1-sided alpha of 2.5% with 90% power based on a log-rank test. It is estimated that 
approximately 580 patients will provide 336 death events after approximately 29 months of 
survival follow-up after the first patient is randomized. EAST® 6.5 was used to calculate the 
sample size.
China Extension Study
Following completion of global enrollment, additional patients from sites in mainland China may 
be enrolled in a China Extension Cohort in the China-specific amendment (if needed). Patients 
randomized in the China extension study will not be included in the above primary efficacy 
population.

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8.12.
Data Monitoring Committee
A multidisciplinary DMC, consisting of therapeutic area experts and biostatisticians who are not 
employed by Gilead, are not investigators for this study, and do not have any major conflict of 
interest, will review the progress of the study, perform interim reviews of safety data at intervals 
of approximately every 6 months after the first patient is randomized unless otherwise specified, 
and will perform the efficacy interim analyses. The DMC will provide recommendation to 
Gilead whether the nature, frequency, and severity of AEs associated with study drugs warrant 
the early termination of the study in the best interests of the patient, whether the study should 
continue as planned, or whether the study should continue with modifications. The DMC may 
also provide recommendations as needed regarding study design.
The DMC’s specific activities will be defined by a mutually agreed charter, which will define the 
DMC’s membership, conduct, and meeting schedule.
While the DMC will be asked to advise Gilead regarding future conduct of the study, including 
possible early study termination, Gilead retains final decision-making authority on all aspects of 
the study.

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

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The ICF will inform patients about genomic testing and/or planned sample retention. In addition 
to the study-specific ICF to be signed by each patient participating in the study, patients will be 
required to document additional consent to provide additional samples and/or to allow the use of 
the remainder of their already-collected specimens for optional future research, in accordance 
with applicable regulations. In addition to the study-specific ICF to be signed by each patient 
participating in the study, patients will be required to document additional consent to provide 
additional samples and/or to allow the use of the existing samples for optional genomic research. 
The results of the tests performed on the samples will not be given to the patient or the 
investigator. The stored biological samples will be destroyed no later than 15 years after the end 
of study or per country requirements, but patients may at any time request that their stored 
samples be destroyed.
9.1.5.
Confidentiality
The investigator must ensure that patients’ anonymity will be strictly maintained and that their 
identities are protected from unauthorized parties. Only an identification code and any other 
unique identifier(s) as allowed by local law (such as year of birth) will be recorded on any form 
or biological sample submitted to Gilead, IRB/IEC, or the laboratory. Laboratory specimens 
must be labeled in such a way as to protect patient identity while allowing the results to be 
recorded to the proper patient. Refer to specific laboratory instructions. NOTE: The investigator 
must keep a screening log with details for all patients screened and enrolled in the study, in 
accordance with the site procedures and regulations. Patient data will be processed in accordance 
with all applicable regulations.
The investigator agrees that all information received from Gilead, including but not limited to the 
IB, this protocol, eCRFs, study drug information, and any other study information, remain the 
sole and exclusive property of Gilead during the conduct of the study and thereafter. This 
information is not to be disclosed to any third party (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 further agrees to take all reasonable precautions to prevent the 
disclosure by any employee or agent of the study site to any third party or otherwise 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) patient 
clinical source documents.
The investigator’s study file will contain the protocol/amendments, eCRFs, IRB/IEC, and 
governmental approval with correspondence, the ICF(s), drug records, staff curriculum vitae and 
authorization forms, and other appropriate documents and correspondence.

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The required source data should include sequential notes containing at least the following 
information for each patient:

Patient identification

Documentation that patient meets eligibility criteria (ie, medical history, physical 
examination, and confirmation of diagnosis [to support inclusion and exclusion criteria])

Documentation of the reason(s) a consented patient is not enrolled

Participation in study (including study number)

Study discussed and date of informed consent

Dates of all visits

Documentation that protocol-specific procedures were performed

Results of efficacy parameters, as required by the protocol

Start and end date (including dose regimen) of study drug, including dates of dispensing and 
return

Record of all AEs and other safety parameters (start and end date; causality and severity) and 
documentation that adequate medical care has been provided for any AE

Concomitant medication (start and end date; dose if relevant; dose changes)

Date of study completion and reason for discontinuation, if it occurs
All clinical study documents must be retained by the investigator for at least 2 years or according 
to local laws, whichever is longer, after the last approval of a marketing application in an ICH 
region (ie, the US, Europe, or Japan) and until there are no pending or planned marketing 
applications in an ICH region; or, if no application is filed or if the application is not approved 
for such indication, for 2 years after the investigation is discontinued and regulatory authorities 
have been notified. Investigators may be required to retain documents longer if specified by 
regulatory requirements, by local regulations, or by an agreement with Gilead. The investigator 
must notify Gilead before destroying any clinical study records.
Should the investigator wish to assign the study records to another party or move them to another 
location, Gilead must be notified in advance.
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 
patient, appropriate copies should be made for storage away from the site.

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9.1.7.
Case Report Forms
For each patient consented, 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. The eCRF casebook will only capture the data required per the protocol schedule 
of events and procedures, unless collected by a non-EDC vendor system (eg, central laboratory). 
The Inclusion/Exclusion Criteria and Enrollment eCRFs should be completed only after all data 
related to eligibility have been received. 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. 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 their 
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 IRBs/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 patients, may be 
made only by Gilead. The investigator must submit all protocol modifications to the IRB/IEC in 
accordance with local requirements and receive documented IRB/IEC approval before 
modifications can be implemented.

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9.2.2.
Study Report and Publications
A clinical study report (CSR) will be prepared and provided to the regulatory agency(ies) when 
applicable and in accordance with local regulatory requirements. Gilead will ensure that the 
report meets the standards set out in the ICH Guideline for Structure and Content of Clinical 
Study Reports (ICH E3). Note that an abbreviated report may be prepared in certain cases. For 
studies with sites in countries following the EU Regulation No. 536/2014, a CSR will be 
submitted within 1 year (6 months for pediatric studies, in accordance with Regulation [EC] 
No. 1901/2006) after the global end of study (as defined in Section 3.5).
Investigators in this study may communicate, orally present, or publish in scientific journals or 
other scholarly media in accordance with the Gilead clinical trial agreement. .
9.3.
Joint Investigator/Sponsor Responsibilities
9.3.1.
Payment Reporting
Investigators and their study personnel may be asked to provide services performed under this 
protocol (eg, attendance at investigator meetings). If required under the applicable statutory and 
regulatory requirements, Gilead will capture and disclose to federal and state agencies any 
expenses paid or reimbursed for such services, including any clinical study payments, meal 
and/or travel expenses or reimbursements, consulting fees, and any other transfer of value.
9.3.2.
Access to Information for Monitoring
In accordance with regulations and guidelines, the study monitor must have direct access to the 
investigator’s source documentation and any patient records to verify the adherence to the 
protocol and the accuracy of the data recorded in the eCRF. The study monitor is responsible for 
routine review of the eCRF at regular intervals throughout the study to verify adherence to the 
protocol and the completeness, consistency, and accuracy of the data being entered on them. The 
investigator agrees to cooperate with the study monitor to ensure that any problems detected 
through any type of monitoring (central, off-site, on-site) are resolved.
9.3.3.
Access to Information for Auditing or Inspections
Representatives of regulatory authorities or Gilead may conduct inspections or audits of the 
clinical study. If the investigator is notified of an inspection by a regulatory authority, the 
investigator agrees to notify the Gilead study monitor immediately. The investigator agrees to 
provide to representatives of a regulatory agency or Gilead access to records, facilities, and 
personnel for the effective conduct of any inspection or audit.
9.3.4.
Study Discontinuation
Both Gilead and the investigator reserve the right to terminate the study at any time. Should this 
be necessary, both parties will arrange discontinuation procedures and notify the patients, 
appropriate regulatory authorities, and IRB/IEC. In terminating the study, Gilead and the 
investigator will ensure that adequate consideration is given to the protection of the patients’ 
interests.

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10.
REFERENCES
American Cancer Society. Cancer Facts & Figures 2021. American Cancer Society, Inc  2021.
CAMPTOSAR, Pharmacia and Upjohn Co. CAMPTOSAR® (Irinotecan) Injection, intravenous 
infusion. U.S. Prescribing Information. NY, NY. Revised December.  2014:
Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron 
1976;16:31-41.
Eisenhauer EA, Therasse P, Bogaerts J, Schwartz LH, Sargent D, Ford R, et al. New Response 
Evaluation Criteria in Solid Tumours: Revised RECIST Guideline (Version 1.1). 
Eur J Cancer 2009;45 (2):228-47.
Ettinger DS, Wood DE, Aggarwal C, Aisner DL, Akerley W, Bauman JR, et al. NCCN 
Guidelines Insights: Non-Small Cell Lung Cancer, Version 1.2020. J Natl Compr 
Canc Netw 2019;17 (12):1464-72.
European Organisation For Research And Treatment Of Cancer (EORTC). EORTC QLQ-C30 
(version 3). Available at: https://qol.eortc.org/questionnaire/eortc-qlq-c30/. 
Accessed: 11 May.  2021:
EuroQol Research Foundation. EQ-5D-3L User Guide: Basic information on how to use the EQ-
5D-3L instrument. Version 6.0. Available at: 
https://euroqol.org/publications/user-guides. Accessed: 11 May 2021. Last 
Updated: December.  2018:
Fossella FV. Docetaxel in second-line treatment of non-small-cell lung cancer. Clin Lung Cancer 
2002;3 Suppl 2:S23-8.
Fossella FV, DeVore R, Kerr RN, Crawford J, Natale RR, Dunphy F, et al. Randomized phase 
III trial of docetaxel versus vinorelbine or ifosfamide in patients with advanced 
non-small-cell lung cancer previously treated with platinum-containing 
chemotherapy regimens. The TAX 320 Non-Small Cell Lung Cancer Study 
Group. J Clin Oncol 2000;18 (12):2354-62.
Goldenberg DM, Cardillo TM, Govindan SV, Rossi EA, Sharkey RM. Trop-2 is a novel target 
for solid cancer therapy with sacituzumab govitecan (IMMU-132), an antibody-
drug conjugate (ADC). Oncotarget 2015;6 (26):22496-512.
Govindan SV, Cardillo TM, Sharkey RM, Tat F, Gold DV, Goldenberg DM. Milatuzumab-SN-
38 conjugates for the treatment of CD74+ cancers. Mol Cancer Ther 2013;12 
(6):968-78.

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Hanna N, Shepherd FA, Fossella FV, Pereira JR, De Marinis F, von Pawel J, et al. Randomized 
phase III trial of pemetrexed versus docetaxel in patients with non-small-cell lung 
cancer previously treated with chemotherapy. J Clin Oncol 2004;22 (9):1589-97.
Horn L, Spigel DR, Vokes EE, Holgado E, Ready N, Steins M, et al. Nivolumab Versus 
Docetaxel in Previously Treated Patients With Advanced Non-Small-Cell Lung 
Cancer: Two-Year Outcomes From Two Randomized, Open-Label, Phase III 
Trials (CheckMate 017 and CheckMate 057). J Clin Oncol 2017;35 (35):3924-33.
International Agency for Research on Cancer (IARC), World Health Organization (WHO). Lung 
Source: Globocan 2020. December.  2020:
Lopez S, Perrone E, Bellone S, Bonazzoli E, Zeybek B, Han C, et al. Preclinical activity of 
sacituzumab govitecan (IMMU-132) in uterine and ovarian carcinosarcomas. 
Oncotarget 2020;11 (5):560-70.
Mazieres J, Rittmeyer A, Gadgeel S, Hida T, Gandara DR, Cortinovis DL, et al. Atezolizumab 
Versus Docetaxel in Pretreated Patients With NSCLC: Final Results From the 
Randomized Phase 2 POPLAR and Phase 3 OAK Clinical Trials. Journal of 
Thoracic Oncology 2021;16 (1):140-50.
National Institutes of Health (NIH). Patient-Reported Outcomes version of the Common 
Terminology Criteria for Adverse Events (PRO-CTCAE™). Available at: 
https://healthcaredelivery.cancer.gov/pro-ctcae/. Accessed: 22 July.  2021:
Ocean AJ, Starodub AN, Bardia A, Vahdat LT, Isakoff SJ, Guarino M, et al. Sacituzumab 
govitecan (IMMU-132), an anti-Trop-2-SN-38 antibody-drug conjugate for the 
treatment of diverse epithelial cancers: Safety and pharmacokinetics. Cancer 
2017;123 (19):3843-54.
Paz-Ares L, Goto Y, Lim WDT, Halmos B, Cho BC, C.M. D, et al. Canakinumab (CAN) + 
docetaxel (DTX) for the second- or third-line (2/3L) treatment of advanced non-
small cell lung cancer (NSCLC): CANOPY-2 phase III results. Ann Oncol 
2021;32 (S5):S953-S4.
Perrone E, Lopez S, Zeybek B, Bellone S, Bonazzoli E, Pelligra S, et al. Preclinical Activity of 
Sacituzumab Govitecan, an Antibody-Drug Conjugate Targeting Trophoblast 
Cell-Surface Antigen 2 (Trop-2) Linked to the Active Metabolite of Irinotecan 
(SN-38), in Ovarian Cancer. Frontiers in oncology 2020;10:118.
Pro Consortium. Non-Small Cell Lung Cancer Symptom Assessment Questionnaire (NSCLC-
SAQ). Available at: https://www.c-pathcoas.org/nsclc-saq. Accessed: 11 May.  
2021:

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Sharkey RM, McBride WJ, Cardillo TM, Govindan SV, Wang Y, Rossi EA, et al. Enhanced 
Delivery of SN-38 to Human Tumor Xenografts with an Anti-Trop-2-SN-38 
Antibody Conjugate (Sacituzumab Govitecan). Clin Cancer Res 2015;21 
(22):5131-8.
Shepherd FA, Dancey J, Ramlau R, Mattson K, Gralla R, O'Rourke M, et al. Prospective 
randomized trial of docetaxel versus best supportive care in patients with non-
small-cell lung cancer previously treated with platinum-based chemotherapy. J 
Clin Oncol 2000;18 (10):2095-103.
Shih LB, Thorpe SR, Griffiths GL, Diril H, Ong GL, Hansen HJ, et al. The processing and fate 
of antibodies and their radiolabels bound to the surface of tumor cells in vitro: a 
comparison of nine radiolabels. J Nucl Med 1994;35 (5):899-908.
Siegel RL, Miller KD, Jemal A. Cancer statistics, 2019. CA Cancer J Clin 2019;69 (1):7-34.
Stein R, Goldenberg DM, Thorpe SR, Basu A, Mattes MJ. Effects of radiolabeling monoclonal 
antibodies with a residualizing iodine radiolabel on the accretion of radioisotope 
in tumors. Cancer Res 1995;55 (14):3132-9.
Taxotere®, Gilead Sciences Inc. Taxotere® (docetaxel) Summary of Product Characteristics. 
Foster City, CA. Revised 06/2020.  1995:
Taxotere®, Gilead Sciences Inc. Taxotere® (docetaxel) Injection Concentrate, Intravenous 
Infusion. U.S. Prescribing Information. Foster City, CA. Revised 05/2020.  1996:
U.S. Department of Health and Human Services (DHHS), Food and Drug Administration (FDA), 
Center for Drug Evaluation and Research (CDER), Center for Biologics 
Evaluation and Research (CBER). Clinical Trial Endpoints for the Approval of 
Non-Small Cell Lung Cancer Drugs and Biologics Guidance for Industry.  April, 
2015.
Zeybek B, Manzano A, Bianchi A, Bonazzoli E, Bellone S, Buza N, et al. Cervical carcinomas 
that overexpress human trophoblast cell-surface marker (Trop-2) are highly 
sensitive to the antibody-drug conjugate sacituzumab govitecan. Sci Rep 2020;10 
(1):973.

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11.
APPENDICES
Appendix 1.
Investigator Signature Page
Appendix 2.
Pandemic Risk Assessment and Mitigation Plan
Appendix 3.
Pregnancy Precautions, Definition for Female of Childbearing Potential, and 
Contraceptive Requirements
Appendix 4.
Toxicity Grading Scale for Severity of Adverse Events and Laboratory 
Abnormalities
Appendix 5.
Eastern Cooperative Oncology Group Performance Status Criteria
Appendix 6.
Response Evaluation Criteria in Solid Tumors (RECIST Version 1.1)
Appendix 7.
UGT1A1 Inhibitors and Inducers
Appendix 8.
Required Prior Treatment With Targeted Therapy Requirement for Patients With 
Known Actionable Genomic Alterations
Appendix 9.
Additional Country-Specific Requirements for United Kingdom and European 
Union
Appendix 10.
Amendment History

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Appendix 1.
Investigator Signature Page
GILEAD SCIENCES, INC.
333 LAKESIDE DRIVE
FOSTER CITY, CA 94404
STUDY ACKNOWLEDGMENT
Open-Label, Global, Multicenter, Randomized, Phase 3 Study of Sacituzumab Govitecan Versus 
Docetaxel in Patients With Advanced or Metastatic Non-Small Cell Lung Cancer (NSCLC) With 
Progression on or After Platinum-Based Chemotherapy and Anti-PD-1/PD-L1 Immunotherapy
GS-US-577-6153, Amendment 2, 22 December 2022
This protocol has been approved by Gilead Sciences, Inc. The following signature documents 
this approval.
[See appended electronic signature]
Director, Clinical Development
Signature
[See appended electronic signature]
Date
INVESTIGATOR STATEMENT
I have read the protocol, including all appendices, and I agree that it contains all necessary 
details for me and my staff to conduct this study as described. I will conduct this study as 
outlined herein and will make a reasonable effort to complete the study within the time 
designated.
I will provide all study personnel under my supervision copies of the protocol and access to all 
information provided by Gilead Sciences, Inc. I will discuss this material with them to ensure 
that they are fully informed about the drugs and the study.
Principal Investigator Name (Printed)
Signature
Date
Site Number
PPD

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Appendix 2.
Pandemic Risk Assessment and Mitigation Plan
During an ongoing pandemic, potential risks associated with patients being unable to attend 
study visits have been identified for this study.
These risks can be summarized as follows:
1) Study drug supplies to patients and sites:
a) Patients may be unable to return to the site for a number of visits to get the study drug, or 
the site may be unable to accept any patient visits. Without study drugs, the patient would 
not be able to continue receiving the study drug as planned per protocol.
Mitigation plan: If permitted by local ethics committee (EC)/institutional review boards 
(IRBs) noninvestigational product as determined by sponsor (ie, docetaxel) can be 
administered at a clinic closer to the patient, under the supervision of a licensed 
physician. If necessary, a dosing delay for SG must be discussed with the sponsor in this 
instance. A virtual study visit, via phone or video conferencing, must be performed prior 
to remote dosing. At the earliest opportunity, the site will schedule in-person patient 
visits and return to the protocol’s regular schedule of assessments. A qualified courier 
may be considered to ship the drug from sites to the alternate clinic.
b) Shipments of study drug could be delayed because of transportation issues. Without study 
drug, the patient would not be able to continue receiving the study drug as planned per 
protocol.
Mitigation plan: The site’s study drug inventory should be closely monitored. Site staff 
should notify the sponsor or delegate if they foresee shortage in study drug inventory or if 
there is any interruption in local shipping service. The sponsor will continue to monitor 
inventory at the study drug depot and investigational sites. Manual shipments will be 
triggered as necessary.
2) Patient safety monitoring and follow-up:
a) Patients may be unable or unwilling to come to the study site for their scheduled study 
visits as required per protocol.
Mitigation plan: For patients who may be unable or unwilling to visit the study site for 
their scheduled study visits as required per protocol, the principal investigator or 
qualified delegate will conduct a remote study visit, via phone or video conferencing, to 
assess the patient within the target visit window date whenever possible. During the 
remote study visit, the following information at minimum will be reviewed:
i)
Confirm if patient has experienced any adverse events (AEs)/serious adverse events 
(SAEs)/special situations (including pregnancy) and follow up on any unresolved 
AEs/SAEs.
ii) Review the current list of concomitant medications and document any new 
concomitant medications.

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b) Patients 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 patient safety until the patient can return to the site for their regular follow up 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) Patients may be unable or unwilling to attend the study visit to sign an updated informed 
consent form version.
Mitigation plan: The site staff will follow their approved consent process and remain in 
compliance with the local EC/IRB and national laws and regulations. Remote consent 
will be allowed if has been approved by the local EC/IRB. The consent process will be 
documented and confirmed by normal consent procedure at the earliest opportunity.
d) The safety of study patients is important and testing of coronavirus disease 2019 
(COVID-19) infection will be based on local clinical guidelines for testing based on 
signs/symptoms and/or suspected exposure to COVID-19.
Mitigation plan: If patient has a diagnosis of COVID-19 while on this clinical study, 
study drug may be held until clinical improvement or resolution in accordance with the 
treating physician’s judgment and general SG dose delay guidance in the protocol. 
Additional supportive care and treatment measures for COVID-19 infection on the study 
will be performed in accordance with local institutional guidelines. Patients with a 
COVID-19 infection while participating in the clinical study will have this event 
documented as an AE in the clinical database.
3) Protocol and monitoring compliance:
a) Protocol deviations may occur in case study visits cannot be conducted as planned per 
protocol.
Mitigation plan: If it is not possible to complete a required procedure, a study visit should 
be conducted as soon as possible when conditions allow. The situation should be 
recorded and explained as a protocol deviation. Any missed patient visits or deviation to 
the protocol due to the pandemic must be reported in the electronic case report form 
(eCRF)and described in the clinical study report. Any remote 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, 
or study drug accountability or assess protocol and Good Clinical Practice compliance. 
This may lead to delays in source data verification, an increase in protocol deviations, or 
under reporting of AEs.

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Mitigation plan: The study monitor is to remain in close communication with the site to 
ensure data entry and query resolution. Remote source data verification may be arranged 
if allowed by local regulation and the Study Monitoring Plan. The study monitor is to 
reference the Study Monitoring Plan for guidance on how to conduct an off-site 
monitoring visit. The study staff is to save and document all relevant communication in 
the study files. The status of sites that cannot accept monitoring visits and/or patients 
on-site, must be tracked centrally and updated on a regular basis.
4) Missing data and data integrity:
There may be an increased amount of missing data due to patients 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 
(eg, 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.
5) Concurrent administration of the COVID-19 vaccine:
There may be potential safety issues due to concurrent administration of the COVID-19 
vaccine and study drugs.
Mitigation plan: There is not substantial efficacy or safety data regarding the concurrent 
administration of the COVID-19 vaccine and SG or docetaxel. Patients are allowed to 
receive the COVID-19 vaccine to reduce the risk and complications of COVID-19 
infection. Investigators and study personnel should provide close surveillance of patients 
after COVID-19 vaccine administration and the institutional guidelines should always be 
followed. The administration of specific COVID-19 vaccine must be documented in the 
clinical database and AEs associated with COVID-19 vaccine administration should be 
recorded in the AE eCRF. COVID-19 vaccine administration should be recorded in the 
prior or concomitant medication eCRF as appropriate. The study visits should continue as 
planned, if possible, and clinically appropriate if vaccination occurs while the patients is 
on the study.
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 patients 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 SG in study patients remains unchanged.

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Appendix 3.
Pregnancy Precautions, Definition for Female of Childbearing 
Potential, and Contraceptive Requirements
1) Definitions
a. Definition of Childbearing Potential
For the purposes of this study, a female-born patient is considered of childbearing potential 
following the initiation of puberty (Tanner stage 2) until becoming postmenopausal unless the 
patient is permanently sterile or has medically documented ovarian failure.
Women 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, women 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 female patient of any age.
b. Definition of Male Fertility
For the purposes of this study, a male-born patient is considered fertile after the initiation of 
puberty unless the patient is permanently sterile by bilateral orchidectomy or medical 
documentation.
2) Contraception Requirements for Female Patients
a. Study Drug Effects on Pregnancy and Hormonal Contraception
Sacituzumab govitecan (SG) is contraindicated in pregnancy because a malformative effect has 
been demonstrated/suspected or is unknown, taking into consideration class effects, and 
genotoxic potential. Based on the assessment of published data related to cytochrome P450 
enzyme inhibition and induction experiments for SN-38, efficacy of hormonal contraception is 
not expected to be impacted due to SG administration. A dedicated oral contraceptive drug-drug 
interaction clinical study has not been conducted. Refer to the latest version of the investigator’s 
brochure for additional information.
Based on the mechanism of action and findings in animals, docetaxel can cause fetal harm when 
administered to a pregnant woman. In nonclinical studies, docetaxel has genotoxic effects. 
Women of childbearing potential should be advised to use effective contraception and avoid 
becoming pregnant during therapy with docetaxel. If the patient becomes pregnant while 
receiving docetaxel, the patient should be apprised of the potential hazard to the fetus. There is 
no contraindication to hormonal contraception according to the docetaxel prescribing 
information. Refer to the docetaxel prescribing information for additional information.

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b. Contraception Requirements for Female Patients of Childbearing Potential
The inclusion of female patients of childbearing potential requires the use of highly effective 
contraceptive measures that have a failure rate of less than 1% per year. Patients must have a 
negative serum pregnancy test at screening and a negative urine pregnancy test is required prior 
to study drug administration on Cycle 1 Day 1. Pregnancy tests will be performed thereafter on 
Day 1 of each treatment cycle starting at Cycle 2 through the last cycle and every 28 days after 
the last dose of study drug up to 6 months after the last dose of study drug until the end of 
contraception requirement. If a urine pregnancy test is positive or equivocal, a confirmatory 
serum pregnancy test will be required.
Duration of required contraception for female patients in this clinical study should start from the 
screening visit until 6 months after the last dose of study drug.
Female patients 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 patient’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 male partner (upon medical assessment of surgical success)
Or
Female patients 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*
Subdermal contraceptive implant*
Transdermal contraceptive patch*
Contraceptive vaginal ring*

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
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
*
Not approved in Japan.
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.
Female patients must also refrain from egg donation, cryopreservation of germ cells, and in vitro 
fertilization during treatment and until the end of contraception requirement. If needed, female 
patients should be advised to seek advice about egg donation and cryopreservation of germ cells 
before treatment.
3) Contraception Requirements for Male Patients
It is theoretically possible that a relevant systemic concentration of study drug may be achieved 
in a female partner from exposure of the male patient’s seminal fluid and pose a potential risk to 
an embryo/fetus. Therefore, male patients with female partners of childbearing potential must 
use condoms during treatment and until 6 months after last dose of study drug. If the female 
partner of childbearing potential is not pregnant, additional contraception recommendations 
should also be considered.
Male patients must also refrain from sperm donation, and/or cryopreservation of germ cells 
during treatment and until the end of contraception requirement. If needed, male patients should 
be advised to seek advice about sperm donation and cryopreservation of germ cells before 
treatment.
4) Unacceptable Birth Control Methods
Birth control methods that are unacceptable include periodic abstinence (eg, calendar, ovulation, 
symptothermal, postovulation methods), withdrawal (coitus interruptus), spermicides only, and 
lactational amenorrhea method. A female condom and a male condom should not be used 
together.
5) Procedures to be Followed in the Event of Pregnancy
Female patients will be instructed to notify the investigator if they become pregnant or suspect 
they are pregnant at any time from start of the study and throughout the study, up to 6 months 
after the last dose of study drug (in female patients), whichever is longer. Sacituzumab govitecan 
must be discontinued immediately upon discussion with the medical monitor.

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Male patients whose partner has become pregnant or suspects she is pregnant from start of study 
and throughout the study, up to 3 months after the last dose of study drug (in male patients with 
female partners), whichever is longer, 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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Appendix 4.
Toxicity Grading Scale for Severity of Adverse Events and 
Laboratory Abnormalities
https://ctep.cancer.gov/protocolDevelopment/electronic_applications/docs/CTCAE_v5_Quick_R
eference_8.5x11.pdf

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Appendix 5.
Eastern Cooperative Oncology Group Performance Status Criteria
Grade
Description
0
Normal activity
Fully active, able to carry on all predisease performance without restriction
1
Symptoms, but ambulatory
Restricted in physically strenuous activity but ambulatory and able to carry out work of a light 
or sedentary nature (eg, light housework, office work)
2
In bed < 50% of the time
Ambulatory and capable of all self-care but unable to carry out any work activities.
Up and about more than 50% of waking hours
3
In bed > 50% of the time
Capable of only limited self-care, confined to bed or chair more than 50% of waking hours
4
100% bedridden
Completely disabled. Cannot carry on any self-care. Totally confined to bed or chair
5
Dead

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Appendix 6.
Response Evaluation Criteria in Solid Tumors (RECIST Version 1.1)
New Response Evaluation Criteria in Solid Tumors: Revised RECIST criteria {Eisenhauer 
2009} are summarized below. Timing of assessments has been modified to fit this protocol.
Measurable/Nonmeasurable Lesions: Each tumor lesion or site of disease identified at baseline 
is categorized as either a measurable lesion or a nonmeasurable lesion according to the following 
definitions.
Lesion type
Qualifying definition
Measurable
Tumor lesions: Must be accurately measured in at least 1 dimension (longest diameter in the 
plane of measurement is to be recorded) with a minimum size of:

10 mm by CT scan (CT scan slice thickness no greater than 5 mm.)

10 mm caliper measurement by clinical examination (lesions which cannot be 
accurately measured with calipers should be recorded as nonmeasurable).

20 mm by chest x-ray.
Malignant lymph nodes: To be considered pathologically enlarged and measurable, a lymph 
node must be 15 mm in short axis when assessed by CT scan (CT scan slice thickness 
recommended to be no greater than 5 mm). At baseline and in follow-up, only the short axis 
will be measured and followed.
Nonmeasurable
All other lesions, including small lesions (longest diameter < 10 mm or pathological lymph 
nodes with 10 to < 15 mm short axis) as well as truly nonmeasurable lesions. Lesions 
considered truly nonmeasurable include leptomeningeal disease, ascites, pleural or 
pericardial effusion, inflammatory breast disease, lymphangitic involvement of skin or lung, 
abdominal masses/abdominal organomegaly identified by physical exam that is not 
measurable by reproducible imaging techniques.
CT = computed tomography
Special considerations regarding lesion measurability:
Bone lesions, cystic lesions, and lesions previously treated with local therapy require particular 
comment:
Bone lesions:

Bone scan, positron emission tomography scan, or plain films are not considered adequate 
imaging techniques to measure bone lesions. However, these techniques can be used to 
confirm the presence or disappearance of bone lesions.

Lytic bone lesions or mixed lytic-blastic lesions, with identifiable soft tissue components, 
that can be evaluated by cross-sectional imaging techniques such as CT or magnetic 
resonance imaging can be considered as measurable lesions if the soft tissue component 
meets the definition of measurability described above.

Blastic bone lesions are nonmeasurable.

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Cystic lesions:

Lesions that meet the criteria for radiographically defined simple cysts should not be 
considered as malignant lesions (neither measurable nor nonmeasurable) since they are, by 
definition, simple cysts.

‘Cystic lesions’ thought to represent cystic metastases can be considered as measurable 
lesions, if they meet the definition of measurability described above. However, if noncystic 
lesions are present in the same patient, these are preferred for selection as target lesions.
Lesions With Prior Local Treatment: Tumor lesions situated in a previously irradiated area, or 
in an area subjected to other loco-regional therapy, are usually not considered measurable unless 
there has been demonstrated progression in the lesion. All measurements should be recorded in 
metric notation, using calipers if clinically assessed. All baseline evaluations should be 
performed as close as possible to the treatment start and never more than 28 days before the 
beginning of the treatment.
Target Lesions: Target lesions are selected from measurable lesions at baseline on the basis of 
their size and suitability for accurate repeated measurements by imaging techniques or clinical 
judgment. The sum of the longest diameter for all target lesions provides a quantitative means of 
characterizing objective tumor response to treatment as follows:
Evaluation Criteria Used for Categorizing Treatment Response of Target Lesions
Response category
Definition
CR
Disappearance of all target lesions
PR
> 30% decrease in the sum of the LD of target lesions, taking as reference the 
baseline sum LD
PD
> 20% increase in the sum of diameters of target lesions, taking as reference the 
smallest sum on study (this includes the baseline sum if that is the smallest on 
study). In addition to the relative increase of 20%, the sum must also demonstrate an 
absolute increase of at least 5 mm. (Note: the appearance of 1 or more new lesions is 
also considered progression).
SD
Neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for 
PD, taking as reference the smallest sum LD since the treatment started
CR = complete response; LD = longest diameter; PD = progressive disease; PR = partial response; SD = stable disease
Nontarget Lesions: Nontarget lesions are other lesions (or sites of disease) not identified as 
target lesions at baseline. These include both nonmeasurable lesions as well as measurable 
lesions exceeding the maximum number allowed per organ or in total. The response of nontarget 
lesions to treatment is evaluated on the basis of their presence or absence as follows:

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Evaluation Criteria Used for Categorizing Treatment Response of Nontarget Lesions
Response category
Definition
CR
Disappearance of all nontarget lesions and normalization of tumor marker levels 
initially above upper limits of normal
PD
Appearance of 1 or more new lesions and/or unequivocal progression of existing 
nontarget lesions
SD
Persistence of 1 or more nontarget lesion(s) or/and maintenance of tumor marker 
level above the normal limits
CR = complete response; PD = progressive disease; SD = stable disease
New Lesions: New lesions not present at baseline should be recorded at time of occurrence.
Overall Response: The overall response is the best response recorded from the start of the 
treatment until disease progression/recurrence (taking as reference for progressive disease (PD) 
the smallest measurements recorded since the treatment started). To be assigned a status of 
partial response (PR) or CR, changes in tumor measurements must be confirmed by repeat 
assessments 4 to 6 weeks after initial documentation. In the case of stable disease (SD), 
follow-up measurements must have met the SD criteria at least once with a minimum interval of 
at least 6 to 8 weeks from enrollment.
Target lesions
Nontarget lesions
New lesions
Overall response
CR
CR
No
CRa
CR
Incomplete response/SD
No
PR
PR
Non-PD
No
PR
SD
Non-PD
No
SD
PD
Any
Yes or No
PDb
Any
PD
Yes or No
PDb
Any
Any
Yes
PDb
CR = complete response; PD = progressive disease; PR = partial response; SD = stable disease
a
When evaluation of possible CR depends on distinguishing residual disease from normal tissue, fine needle aspirate/biopsy 
is recommended before confirming the complete response status.
b
Patients without objective evidence of disease progression, but with globally deteriorated health status requiring 
discontinuation of treatment, should be classified as having “symptomatic deterioration” at that time, with every effort made 
to document the objective progression, even after discontinuation of treatment.
Duration of Response: The duration of overall response is measured from the time 
measurement criteria are met for CR or PR (whichever is first recorded) until the first date that 
recurrent or PD is objectively documented (taking as reference for PD the smallest 
measurements recorded since the treatment started). Stable disease is measured from the start of 
the treatment until the criteria for progression are met, taking as reference the smallest 
measurements recorded since the treatment started.

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Appendix 7.
UGT1A1 Inhibitors and Inducers
Inducers of UGT1A1
Inhibitors of UGT1A1
Carbamazepine
Efavirenz
Ethinylestradiol
Lamotrigine
Phenobarbital
Phenytoin
Primidone
Rifampicin
Ritonavir
Tipranavir
Amitriptyline
Atazanavir
Dacomitinib
Dasabuvir
Deferasirox
Eltrombopag
Enasidenib
Erlotinib
Flunitrazepam
Flurbiprofen
Fostamatinib
Gemfibrozil
Glecaprevir
Indinavir
Indomethacin
Ketoconazole
Nilotinib
Ombitasvir
Paritaprevir
Pazopanib
Pexidartinib
Pibrentasvir
Probenecid
Propofol
Regorafenib
Rucaparib
Silibinin
Sorafenib
Valproic acid

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Amendment 2
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Appendix 8.
Required Prior Treatment With Targeted Therapy Requirement for 
Patients With Known Actionable Genomic Alterations
Prior treatment with at least ONE of the options listed below is required for known specific 
genomic alteration if at least 1 of the listed medications for the genomic alteration is approved 
and available locally. If a patient has received a locally approved medication that is not listed 
here, sponsor consultation is required for confirmation of eligibility.
Activating Genomic Alteration
Required Prior Therapy
EGFR sensitizing
erlotinib, gefitinib, afatinib, dacomitinib, osimertinib, lazertinib
EGFRT790M
osimertinib, lazertinib
EGFR exon 20 insertion
amivantamab
ALK
crizotinib, ceritinib, alectinib, lorlatinib, brigatinib
ROS1
entrectinib, larotrectinib, crizotinib
NTRK
entrectinib, larotrectinib
BRAFV600E
dabrafenib and trametinib (in combination)
MET exon 14 skipping
capmatinib, tepotinib
RET
selpercatinib, pralsetinib
KRASG12C
sotorasib
ALK = anaplastic lymphoma kinase; BRAF = proto-oncogene B-raf; EGFR = epidermal growth factor receptor; KRAS = Kirsten 
rat sarcoma virus; MET = mesenchymal-epithelial transition; NTRK = neurotrophic tyrosine receptor kinase; RET = rearranged 
during transfection; ROS1 = ROS proto-oncogene 1

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Amendment 2
CONFIDENTIAL
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Appendix 9.
Additional Country-Specific Requirements for United Kingdom and 
European Union
Reflects the changes to the global Amendment 1 protocol dated 15 September 2021 and reflected 
in Amendment 1.1 (United Kingdom) dated 29 November 2021.
Country-specific Requirements
Protocol 
Section
In the United Kingdom and EU, diagnostic testing for EGFR, ALK, and PD-L1 to determine 
eligibility at screening will be performed with tests that are approved for use in the EU. EGFR 
testing will be performed using the Cobas® EGFR Mutation Test (Roche). For ALK, the Vysis 
ALK Break Apart FISH probe test (Abbott) will be used. PD-L1 testing will be performed 
with the PD-L1 IHC 22C3 pharmDx test (Dako).
Section 6.3.10
ALK = anaplastic lymphoma kinase; EGFR = epidermal growth factor receptor; EU = European Union, PD-L1 = programmed 
death ligand 1

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Amendment 2
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Appendix 10.
Amendment History
A high-level summary of this amendment is provided in tabular form in the subsection below, 
with changes listed in order of importance. Minor changes such as the correction of typographic 
errors, grammar, or formatting are not detailed.
Earlier separate summaries of changes are available upon request.
A separate tracked change (red-lined) document comparing Amendment 1 to this amendment 
will be made available upon the publication of this protocol.
Appendix Table 1.
Amendment 2 (22 December 2022)
Rationale for Key Changes Included in Amendment 2
Affected Sections
The sample size was updated to 580 patients and the study power is increased to 
90% due to change in the assumptions for activity of the control arm (docetaxel) 
from recent data outside of this protocol.
Synopsis, Study Schema, 
Sections 3.1, 4.1, 8.11, and 
8.2
Secondary PRO endpoints were updated to time to first deterioration for 
NSCLC-SAQ shortness of breath domain and total score to align with approaches 
used for the primary endpoints and increase likelihood of generating a significant 
difference between treatment arms,
Synopsis, Sections 2, 3.1, 
8.5.2.1, and 8.7
Exploratory PRO endpoints were updated to mean change from baseline for 
NSCLC-SAQ shortness of breath domain and total score.
Synopsis, Section 2
Additional text was added to describe the extension study in China.
Synopsis, Sections 3.1, and 
8.11
Clarification was added on follow-up requirements for patients who complete or 
withdraw from the study.
Sections 3.4.4 and 6.3.7
Inclusion criterion was updated to indicate testing for patients with squamous cell 
carcinoma. EGFR and ALK testing is optional because among the patients with 
squamous cell carcinoma, mutation rates for EGFR and ALK are very low or rare.
Section 4.2
Criteria for discontinuation and timing of dose reductions of sacituzumab 
govitecan have been updated to align with current guidelines.
Section 5.5.1
The interim futility analysis was removed since the study is enrolling ahead of 
projected schedule and enrollment would likely be completed around the time of 
DMC meeting for futility evaluation. Overall safety and efficacy will continue to 
be monitored by an independent DMC.
Sections 8.2.1, 8.7, and 8.12
Country-specific requirements from Amendments 1.1 for the UK were included in 
the global protocol.
Appendix 9
Biomarker analysis was updated to include “Baseline Trop-2 analysis will be 
performed and correlated with clinical outcomes” to strengthen language for 
Trop-2 analysis.
Section 8.10
Text was updated to align with reporting requirements.
Section 9.2.2
ALK = anaplastic lymphoma kinase; EGFR = epidermal growth factor receptor; NSCLC-SAQ = non-small cell lung cancer 
Symptom Assessment Questionnaire; PRO = patient-reported outcomes; Trop-2 = trophoblast cell surface antigen-2; 
UK = United Kingdom.

Prot GS-US-577-6153 amd-2
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