A Phase 2, Open-Label, Single-Arm Study of Single-Dose Lead-In and Neoadjuvant Trilaciclib and Chemotherapy in Patients With Early-Stage Triple Negative Breast Cancer (TNBC)
Phase: PHASE2
Conditions: Triple Negative Breast Cancer, Breast Cancer
Sponsor: G1 Therapeutics, Inc.

Protocol  
 
G1T28-212 
Version 2.0 dated 23 Mar 2022 
 
 
 
1 
 
 
 
Protocol Title: A Phase 2, Open-Label, Single-Arm Study of Single-Dose Lead-In and 
Neoadjuvant Trilaciclib and Chemotherapy in Patients with Early-Stage Triple 
Negative Breast Cancer (TNBC) 
Protocol Number: G1T28-212 
Compound: Trilaciclib for Injection, 300 mg/vial 
Study Phase: 2 
Study Name: G1T28-212 
Sponsor Name: G1 Therapeutics, Inc. 
Legal Registered Address:  G1 Therapeutics, Inc. 
700 Park Offices Dr. Suite 200 
PO Box 110341  
Research Triangle Park, NC 27709 
 
Regulatory Agency Identifier Numbers:  IND 145091 
 
Approval Date: 23 Mar 2022 (Version 2.0) 
Previous Version: 30 Jun 2021 (Version 1.0) 
 
 
This document contains confidential and/or trade secret information that is disclosed only in connection 
with the licensing and/or registration of products for G1 Therapeutics, Inc. This document should not be 
disclosed or used, in whole or in part, for any other purpose without the prior written consent of 
G1 Therapeutics, Inc. 

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INVESTIGATOR’S AGREEMENT 
 
Clinical Study Protocol G1T28-212: A Phase 2, Open-Label, Single-Arm Study of Single-Dose 
Lead-In and Neoadjuvant Trilaciclib and Chemotherapy in Patients with Early-Stage Triple 
Negative Breast Cancer (TNBC) 
 
Protocol (Version 2.0) Issue Date: 23 Mar 2022 
 
I have read the G1T28-212 protocol and agree to conduct the study as outlined. I agree to 
maintain the confidentiality of all information received or developed in connection with this 
protocol.  
 
 
 
 
 
 
Principal Investigator Signature 
 
Date 
 
 
 
 
 
 
 
 
Principal Investigator Name 
 
Institution 
 
 

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1. 
SYNOPSIS 
Name of Sponsor/Company: G1 Therapeutics, Inc. 
Name of Investigational Product: Trilaciclib for Injection, 300 mg/vial  
Name of Active Ingredient: trilaciclib dihydrochloride (hereafter referred to as trilaciclib) (G1T28) 
Protocol Number: G1T28-212 
Phase: 2 
Regions: United States 
Title of Study:  
A Phase 2, Open-Label, Single-Arm Study of Single-Dose Lead-In and Neoadjuvant Trilaciclib and 
Chemotherapy in Patients with Early-Stage Triple Negative Breast Cancer (TNBC) 
Study centers: Approximately 10 centers 
Study period (years): Approximately 15 months  
Date first patient enrolled: Q1 2022 
Estimated date last patient enrolled: Q3 2022  
Estimated date last patient completed: Q1 2023 
Objectives: 
Primary objective: 
To evaluate the immune-based mechanism of action of trilaciclib after a single-dose as measured by 
the change in cluster of differentiation 8 positive (CD8+) tumor-infiltrating lymphocytes 
(TILs)/regulatory T cell (Treg) ratio in tumor tissue. 
Secondary objectives:  
To assess the pathologic complete response (pCR) rate at the time of definitive surgery. 
To evaluate the safety and tolerability of trilaciclib in combination with standard neoadjuvant 
systemic therapies. 
Exploratory objectives: 
To characterize the intratumoral immune profile following trilaciclib.  
To evaluate the kinetics of the peripheral immune response following trilaciclib. 
To identify molecular and cellular biomarkers in tumor or blood samples that may be indicative of 
clinical response/resistance, pharmacodynamic activity, and/or the mechanism of action of trilaciclib 
and other systemic treatments. 
Study Design: 
This is a Phase 2 multicenter, open-label, single-arm, neoadjuvant study with 4 phases: 1) Screening 
Phase, 2) Trilaciclib Lead-In Phase, 3) Treatment Phase, and 4) Surgery and Follow-Up Phase.  
During the Screening Phase, tumor tissue (sample #1) will be obtained at baseline prior to any study 
drug. This sample may be archival tissue, or if unavailable/insufficient, then a fresh biopsy is 
required. Patients with adequate archival tissue will also have the option to undergo an additional 
fresh biopsy at baseline. Patients will receive a single dose of monotherapy trilaciclib 240 mg/m2 in 
the Trilaciclib Lead-In Phase, followed by tumor biopsy (sample #2) 7 (±1) days later. Following the 
biopsy, patients will enter the Treatment Phase in which trilaciclib 240 mg/m2 on Day 1 of each cycle 
will be administered along with dose-dense anthracycline/cyclophosphamide followed by weekly 
taxane chemotherapy (doxorubicin 60 mg/m2 + cyclophosphamide 600 mg/m2 [AC] every 2 weeks 
for 4 cycles [Cycles 1-4], then weekly paclitaxel [T] 80 mg/m2 weekly for 12 cycles [Cycles 5-16]). If 

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pembrolizumab is given (per Investigator discretion), it will start with AC (Cycle 1 of chemotherapy). 
If carboplatin is given (per Investigator discretion) it will start with paclitaxel (Cycle 5).  
Three to 5 weeks after the last dose of chemotherapy, patients will proceed to definitive surgery at 
which time tumor tissue (sample #3) will be collected if the patient has residual disease. A 30-day 
Safety Follow-up Visit will occur 30 (+7) days after last dose of trilaciclib and an End of Study Visit 
will occur within 14 days after surgery. Both the Safety Follow-up Visit and End of Study Visit may 
be conducted in person or by telephone and may occur at the same visit.  
Methodology:  
Sample Size Justification:  
Sample size justification is based off of previously published data on the CD8+/Treg ratio 
from early stage TNBC patients who underwent neoadjuvant chemotherapy. Using a 
2-sided significance level of 0.05, and anticipating that 10% patients enrolled to this study 
will not have paired data (resulting in 27 patients with paired data), the power of the study 
to detect a respective mean of paired difference in CD8+/Tregs ratio using paired Wilcoxon 
signed-rank tests has been calculated using PASS 2019 (v19.0.3) and is presented in the 
table below. 
 
Mean Change in CD8+/Tregs 
Power 
1.8 
72% 
2.0 
81% 
2.3 
90% 
2.5 
94% 
Based on the assumption of an estimated standard deviation of paired differences of 3.4. 
Number of patients (planned): Approximately 30 patients are planned to be enrolled in this study. 
Diagnosis and main eligibility criteria:  
Female patients ≥18 years of age at the time of signing the informed consent with treatment-naïve 
early-stage breast cancer in which neoadjuvant chemotherapy with an anthracycline/taxane 
combination is deemed to be a suitable therapy and curative surgery is intended. Documented 
diagnosis of TNBC (defined as <1% estrogen receptor [ER] and progesterone receptor [PR] positive 
stained cells utilizing an assay consistent with local standards and HER2-negative as per 2018 
College of American Pathologists criteria), a primary tumor ≥1.5 cm, and an Eastern Cooperative 
Oncology Group (ECOG) performance status of 0 or 1. Patients must also have adequate organ 
function as demonstrated by laboratory values and left ventricular ejection fraction of ≥50% or 
≥ institution lower limit of normal (LLN). If the Investigator chooses to add pembrolizumab, there 
must be no active autoimmune disease that has required systemic treatment in the past 2 years or 
corticosteroids within the past 7 days. Patients are required to have baseline archival tumor tissue 
available or a fresh biopsy must be obtained, and patient must agree to an on-treatment research 
biopsy. 
Investigational product, dosage, and mode of administration: 
Trilaciclib will be administered as monotherapy as a single dose of 240 mg/m2 intravenously (IV) 
over 30 minutes during the Trilaciclib Lead-In Phase of the study, and then at the same dose with 
each chemotherapy cycle during the Treatment Phase.  
Duration of treatment: Study treatment will continue as per protocol to completion or early 
discontinuation of chemotherapy, until unacceptable toxicity, Investigator’s decision to withdraw the 
patient from study treatment, pregnancy of the patient, noncompliance with study treatment or 

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procedure requirements, consent withdrawal, becoming lost-to-follow-up, death, or administrative 
reasons requiring cessation of treatment. 
Standard of care chemotherapy backbone, dosage, and mode of administration:  
Doxorubicin 60 mg/m2 and cyclophosphamide 600 mg/m2 will be administered IV once every 
2 weeks in Cycles 1-4, followed by paclitaxel 80 mg/m2 administered IV once every week in 
Cycles 5-16.  
Treatment per Investigator discretion, dosage, and mode of administration: 
Carboplatin: If carboplatin is administered, the dose amount required will be calculated as area under 
the curve (AUC) at a dose level of AUC 1.5 weekly during paclitaxel treatment (Cycle 5-16). 
Carboplatin will be administered IV. 
Pembrolizumab: If pembrolizumab is administered, the dose level will be 400 mg every 6 weeks 
starting with Cycle 1 of AC and continued while receiving chemotherapy. Pembrolizumab will be 
administered as an IV infusion. 
Growth factor support: 
Granulocyte-colony stimulating factor (G-CSF) should be administered after each cycle of AC 
chemotherapy or per Investigator discretion and as clinically indicated for subsequent cycles with 
paclitaxel. G-CSF 5 μg/kg/day administered subcutaneously (SC) should be initiated at 24 hours 
post-dose and continued for at least 72 hours. Pegfilgrastim administered SC as either a single dose of 
100 μg/kg (individualized) or a single dose of 6 mg (general approach) at 24 hours after 
chemotherapy is also acceptable. 
Criteria for evaluation:  
Efficacy: pCR will be evaluated using the definition of ypT0/Tis ypN0 (i.e., no invasive residual in 
breast or nodes; residual noninvasive in breast allowed) as assessed by the local pathologist at the 
time of definitive surgery. 
Safety: Safety will be evaluated by monitoring adverse events (AEs), clinical laboratory test results 
(hematology and serum chemistry), and vital sign measurements (blood pressure and pulse rate) as 
well as electrocardiogram (ECG) and ejection fraction changes if clinically indicated. 
Statistical methods:  
Summary statistics will be used to summarize data collected from this study. The descriptive 
summary for the categorical variables will include counts and percentages. The descriptive summary 
for the continuous variables will include means, standard deviations, medians, 25% and 75% 
percentiles, and minimum and maximum values. For the immune-response measures and other 
biomarkers, median will be used to present the central point of the population being studied.  
Analysis population 
The Full Analysis Set - 1 (FAS1) population includes enrolled patients who have received trilaciclib 
during the Trilaciclib Lead-in Phase. This dataset will be used to assess immune response in tumor 
tissue. 
The Full Analysis Set – 2 (FAS2) population includes enrolled patients who have received at least one 
dose of a study drug during the Treatment Phase of the study. This dataset will be used to assess 
safety and tolerability and the rate of pCR for trilaciclib in combination with neoadjuvant systemic 
therapies.  
Statistical analysis method for primary and secondary efficacy endpoints 
Analysis for primary immune-response measure 
Summary statistics for primary immune-response measure, the ratio of CD8+ TIL over Forkhead Box 
P3 (FOXP3)+ regulatory T cells (abbreviated as CD8+/Tregs), will be provided for measures taken at 

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baseline (pre-trilaciclib), 7 ± 1 days after single dose trilaciclib (post-trilaciclib), and the change 
scores (post minus pre). Median will be used as the central point with Q1 and Q3 as the measure of 
spread. The significance of the magnitude of change will be tested by paired Wilcoxon Signed-Rank 
test. Analyses on the primary endpoint will be based on the FAS1 population. 
Analysis for pCR 
For the clinical efficacy endpoint, pCR rate will be reported with a 95% confidence interval using the 
Clopper-Pearson method based on FAS2 population. In addition, patients will be dichotomized by 
median value of changes in CD8+/Tregs ratio, and pCR rate will be summarized by the subgroup of 
patients with high or low change scores. The association between pCR status and high/low in ratio 
change will be tested using a Chi-square test. These analyses will be performed on the FAS2 
population.  
Analysis for safety endpoints 
For trilaciclib alone, safety will be assessed by AE reporting during the Trilaciclib Lead-in Phase 
based on FAS1 population. For trilaciclib in combination with other systemic therapies, safety and 
tolerability will be assessed by AEs, dose modification, laboratory tests, vital signs, and ECGs based 
on FAS2 population. AEs are defined as those events occurring or worsening after treatment has 
begun on this study. Collected AE terms will be coded to system organ class and preferred term using 
the latest version of MedDRA. AEs will be graded according to the National Cancer Institute 
Common Terminology Criteria for Adverse Events (CTCAE) v5.0 by Investigators. AEs overall, AEs 
related to each study drug, AEs leading to study drug discontinuation or dose modification, and AEs 
of special interests for trilaciclib will be summarized by system organ class, preferred term and 
CTCAE grade, as appropriate. In the tabulation of severity and causality for an AE, if the same AE 
occurs on multiple occasions, the highest grade and strongest relationship to study drug will be used. 
Concomitant medications will be coded to Anatomical Therapeutic Classification using the World 
Health Organization-Drug Dictionary and summarized. 
For laboratory assessments, vital signs, and ECG parameters, observed values and changes from 
baseline will be summarized. Chemistry and hematology laboratory parameters will be characterized 
according to CTCAE toxicity grade from 1 to 5, v5.0 when possible, and the number and percentage 
of patients within each CTCAE grade will be summarized for the overall treatment period as well as 
for each cycle. Safety data collected through scheduled or unscheduled visits will all be included in 
the safety evaluation.  

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2. 
TABLE OF CONTENTS, LIST OF TABLES, AND LIST OF 
FIGURES  
TABLE OF CONTENTS 
PROTOCOL SIGNATURE PAGE .................................................................................................2 
INVESTIGATOR’S AGREEMENT ...............................................................................................3 
1. 
SYNOPSIS ...................................................................................................................4 
2. 
TABLE OF CONTENTS, LIST OF TABLES, AND LIST OF FIGURES .................8 
3. 
LIST OF ABBREVIATIONS.....................................................................................13 
4. 
INTRODUCTION ......................................................................................................17 
4.1. 
Triple Negative Breast Cancer ....................................................................................17 
4.1.1. 
T Cell Activity and the Tumor Microenvironment .....................................................17 
4.2. 
Trilaciclib ....................................................................................................................18 
4.2.1. 
Clinical Data with Trilaciclib in TNBC ......................................................................20 
4.2.2. 
T Cell Activity with Trilaciclib ..................................................................................21 
4.3. 
Study Rationale ...........................................................................................................21 
4.4. 
Background .................................................................................................................22 
4.4.1. 
Summary of Nonclinical Data ....................................................................................22 
4.4.1.1. 
Pharmacology Studies ................................................................................................22 
4.4.1.2. 
Pharmacokinetic Studies .............................................................................................24 
4.4.2. 
Summary of Clinical Data ..........................................................................................24 
4.4.2.1. 
Clinical Trials .............................................................................................................24 
4.4.3. 
Risks ...........................................................................................................................27 
4.4.3.1. 
Trilaciclib ....................................................................................................................27 
4.4.3.2. 
Doxorubicin, Cyclophosphamide, and Paclitaxel .......................................................29 
4.4.3.3. 
Treatment per Investigator Discretion: Carboplatin and Pembrolizumab ..................31 
4.4.3.4. 
Tumor Biopsy Collection ...........................................................................................32 
4.5. 
Benefit/Risk Assessment ............................................................................................32 
5. 
OBJECTIVES AND ENDPOINTS ............................................................................33 
6. 
INVESTIGATIONAL PLAN .....................................................................................34 
6.1. 
Overall Study Design ..................................................................................................34 
6.2. 
Rationale for the Primary Endpoint ............................................................................36 
6.3. 
Rationale for Tumor Biopsy Collection .....................................................................36 

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6.4. 
Rationale for Peripheral Blood Collection .................................................................37 
6.5. 
Rationale for Dose and Schedule of Trilaciclib ..........................................................37 
6.6. 
Rationale for Patient Population .................................................................................37 
6.7. 
Rationale for Neoadjuvant Therapy in TNBC and Secondary pCR Endpoint ...........38 
6.8. 
Rationale for Anthracycline/Taxane-Based Chemotherapy .......................................38 
6.9. 
Rationale for Pembrolizumab (per Investigator Discretion) ......................................38 
6.10. 
Rationale for Carboplatin (per Investigator Discretion) .............................................39 
7. 
STUDY POPULATION .............................................................................................41 
7.1. 
Inclusion Criteria ........................................................................................................41 
7.2. 
Exclusion Criteria .......................................................................................................42 
8. 
SCHEDULE OF ASSESSMENTS.............................................................................44 
9. 
STUDY TREATMENT ..............................................................................................47 
9.1. 
Study Drugs Administered .........................................................................................47 
9.1.1. 
Dose, Dosing Regimen, and Route .............................................................................49 
9.1.1.1. 
Trilaciclib ....................................................................................................................49 
9.1.1.2. 
Chemotherapy Backbone: Doxorubicin, Cyclophosphamide, and Paclitaxel ............50 
9.1.1.3. 
Treatment per Investigator Discretion: Carboplatin and Pembrolizumab ..................50 
9.1.2. 
Preparation, Handling, Storage, and Accountability ..................................................51 
9.1.3. 
Treatment Compliance ................................................................................................51 
9.2. 
Criteria for Starting Study Treatment and Each Subsequent Cycle ...........................51 
9.3. 
Toxicity Management and Dose Modifications .........................................................51 
9.3.1. 
Dose Modifications for Trilaciclib .............................................................................52 
9.3.2. 
Dose Modifications for Chemotherapy ......................................................................52 
9.3.3. 
Dose Modifications for Pembrolizumab .....................................................................57 
9.3.4. 
Discontinuation of a Component or Entire Regimen .................................................58 
9.3.5. 
Recommended Actions with Trilaciclib for Adverse Events of Special 
Interest ........................................................................................................................59 
9.3.6. 
Hy’s Law Management ...............................................................................................61 
9.3.7. 
Management of Nausea and Vomiting .......................................................................61 
9.4. 
Supportive Care Interventions ....................................................................................61 
9.4.1. 
Granulocyte-Colony Stimulating Factor Usage ..........................................................61 
9.4.2. 
Transfusions ................................................................................................................62 
9.5. 
Prior/Concomitant Medications, Procedures, and Vaccinations ................................62 

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10. 
DISCONTINUATION OF STUDY TREATMENT AND PATIENT 
DISCONTINUATION/WITHDRAWAL ..................................................................64 
10.1. 
Discontinuation of Study Treatment ...........................................................................64 
10.2. 
Discontinuation/Withdrawal from the Study ..............................................................64 
10.3. 
Lost to Follow Up .......................................................................................................65 
10.4. 
Study and Site Start and Closure ................................................................................65 
11. 
STUDY ASSESSMENTS ..........................................................................................66 
11.1. 
Screening Assessments ...............................................................................................66 
11.1.1. 
ER-, PR-, HER2-Negative Status ...............................................................................66 
11.1.2. 
Baseline Characteristics and Demographics ...............................................................66 
11.1.3. 
Medical and Surgical History .....................................................................................66 
11.2. 
Biomarker and Efficacy Assessments ........................................................................67 
11.2.1. 
Tumor Biopsy Collection ...........................................................................................67 
11.2.2. 
Blood Collection .........................................................................................................68 
11.2.3. 
Pathologic Complete Response ..................................................................................68 
11.3. 
Safety Assessments .....................................................................................................69 
11.3.1. 
Vital Signs ..................................................................................................................69 
11.3.2. 
Physical Examination .................................................................................................69 
11.3.3. 
ECOG Performance Status .........................................................................................69 
11.3.4. 
Clinical Safety Laboratory Assessments ....................................................................70 
11.3.5. 
Electrocardiogram .......................................................................................................70 
11.3.6. 
Echocardiogram or MUGA ........................................................................................70 
11.3.7. 
Adverse and Serious Adverse Events .........................................................................71 
11.3.7.1. 
Time Period and Frequency for Collecting Adverse and Serious Adverse 
Event Information .......................................................................................................71 
11.3.7.2. 
Method of Detecting Adverse and Serious Adverse Events .......................................71 
11.3.7.3. 
Follow-up of Adverse and Serious Adverse Events ...................................................71 
11.3.7.4. 
Regulatory Reporting Requirements for Serious Adverse Events .............................72 
11.3.7.5. 
Pregnancy ...................................................................................................................72 
11.3.8. 
Definitive Surgery ......................................................................................................72 
11.4. 
Safety Monitoring Committee ....................................................................................73 
11.5. 
Safety Follow-up Visit ................................................................................................73 
11.6. 
End of Study Visit ......................................................................................................73 

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12. 
STATISTICAL CONSIDERATIONS .......................................................................74 
12.1. 
Sample Size Determination ........................................................................................74 
12.2. 
Analysis Population ....................................................................................................74 
12.3. 
Statistical Analysis Methods.......................................................................................74 
12.3.1. 
General Considerations ...............................................................................................74 
12.3.2. 
Patient Disposition ......................................................................................................74 
12.3.3. 
Demographic and Baseline Characteristics ................................................................75 
12.3.4. 
Study Drug Exposure, Modification and Dose Intensity ............................................75 
12.3.5. 
Efficacy Analyses .......................................................................................................75 
12.3.5.1. 
Analyses for Primary Immune-Response Measure ....................................................75 
12.3.5.2. 
Analyses for pCR ........................................................................................................75 
12.3.6. 
Safety Analyses ..........................................................................................................76 
12.3.6.1. 
Adverse Events ...........................................................................................................76 
12.3.6.2. 
Other Safety Endpoints ...............................................................................................76 
12.3.7. 
Exploratory Analyses ..................................................................................................76 
13. 
ETHICS ......................................................................................................................77 
13.1. 
Ethics Review .............................................................................................................77 
13.2. 
Ethical Conduct of the Study ......................................................................................77 
13.3. 
Written Informed Consent ..........................................................................................77 
14. 
DATA HANDLING AND RECORDKEEPING .......................................................78 
14.1. 
Data Protection ...........................................................................................................78 
14.2. 
Data Quality Assurance ..............................................................................................78 
14.3. 
Dissemination of Clinical Study Data ........................................................................79 
14.4. 
Source Documents ......................................................................................................79 
14.5. 
Audits and Inspections ................................................................................................79 
15. 
PUBLICATION POLICY ..........................................................................................80 
16. 
REFERENCES ...........................................................................................................81 
17. 
APPENDICES ............................................................................................................86 
17.1. 
Clinical Laboratory Tests ...........................................................................................86 
17.2. 
Adverse Events: Definitions and Procedures for Recording, Evaluating, and 
Follow-up ....................................................................................................................87 
17.2.1. 
Definition of AE .........................................................................................................87 
17.2.2. 
Definition of SAE .......................................................................................................88 

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17.2.3. 
Recording and Follow-Up of AE and/or SAE ............................................................89 
17.2.4. 
Reporting of SAEs ......................................................................................................91 
17.3. 
Contraceptive Guidance and Collection of Pregnancy Information ...........................92 
 
LIST OF TABLES 
Table 1: 
Abbreviations ..............................................................................................................13 
Table 2: 
Potentially Significant Drug Interactions with Trilaciclib ..........................................27 
Table 3:  
Objectives and Endpoints ...........................................................................................33 
Table 4:  
Schedule of Assessments ............................................................................................45 
Table 5:  
Study Drugs ................................................................................................................48 
Table 6: 
Dose Modification Recommendations for Doxorubicin and 
Cyclophosphamide (AC) ............................................................................................52 
Table 7: 
Dose Modification Recommendations for Paclitaxel Alone or With 
Carboplatin .................................................................................................................54 
Table 8: 
Dose Modification Recommendations for Pembrolizumab .......................................57 
Table 9:  
Recommended Actions with Trilaciclib Following AESIs ........................................59 
Table 10: ECOG Performance Status .........................................................................................69 
Table 11: Protocol-Specified Safety Laboratory Assessments ...................................................86 
 
LIST OF FIGURES 
Figure 1: 
Trilaciclib Transiently Arrests Normal Cells to Prevent Chemotherapy 
Induced Myelosuppression and Improve Anti-Tumor Efficacy .................................19 
Figure 2: 
The Addition of Trilaciclib to Chemotherapy/Checkpoint Inhibitor 
Treatment Enhances Efficacy Through T Cell Activation .........................................23 
Figure 3:  Study Schema .............................................................................................................35 
Figure 4: 
Sequence of Administration of IV Study Drugs .........................................................51 
 
  

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3. 
LIST OF ABBREVIATIONS  
The following abbreviations and specialist terms are used in this study protocol. 
Table 1: 
Abbreviations  
Abbreviation 
Definition 
5-FU 
5-fluorouracil 
AC 
anthracycline/cyclophosphamide 
AC/T 
anthracycline/cyclophosphamide/taxane 
AE 
adverse event 
AESI 
adverse event of special interest 
AJCC 
American Joint Committee of Cancer 
ALT 
alanine aminotransaminase 
ASCO 
American Society of Clinical Oncology 
AST 
aspartate aminotransferase 
AUC 
area under the plasma concentration-time curve 
β-hCG 
beta human chorionic gonadotropin  
BSA 
body surface area 
CBC 
complete blood count 
CD8+ 
cluster of differentiation 8 positive 
CDK 
cyclin-dependent kinase  
CI 
confidence interval 
COVID-19 
coronavirus disease 19 
CTCAE 
Common Terminology Criteria for Adverse Events 
CTLA-4 
cytotoxic T-lymphocyte associated protein 4 
CYP 
cytochrome P450 
DCIS 
ductal carcinoma in situ 
DDI 
drug-drug interaction 
DFS 
disease-free survival 
DSN 
duration of severe neutropenia 
ECG 
electrocardiogram 
ECHO 
echocardiogram 
ECOG 
Eastern Cooperative Oncology Group  
eCRF 
electronic case report form 
EFS 
event-free survival 

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Abbreviation 
Definition 
E/P 
etoposide plus carboplatin 
E/P/A 
etoposide, carboplatin, and atezolizumab 
ER 
estrogen receptor 
ES-SCLC 
early-stage small cell lung cancer 
FACT-B 
Functional Assessment of Cancer Therapy - Breast 
FAS 
Full Analysis Ste 
FDA 
Food and Drug Administration 
FFPE 
formalin-fixed paraffin-embedded 
FOXP3 
Forkhead Box P3 
FSH 
follicle stimulating hormone 
G1 
gap 1 phase of the cell cycle 
GC 
gemcitabine and carboplatin 
GCP 
Good Clinical Practice 
G-CSF 
granulocyte colony-stimulating factor 
GM-CSF 
granulocyte-macrophage colony-stimulating factor 
GnRH 
gonadotrophin-releasing hormone 
HBV 
hepatitis B virus 
HCV 
hepatitis C virus 
HER2 
human epidermal growth factor receptor 2 
HIV 
human immunodeficiency virus 
HRT 
hormone replacement therapy 
HSPC 
hematopoietic stem and progenitor cell 
IB 
Investigator’s Brochure 
ICF 
informed consent form 
ICH 
International Council for Harmonisation 
ICI 
immune checkpoint inhibitors 
IEC 
independent ethics committee  
IFN 
interferon 
IHC 
immunohistochemistry 
ILD 
interstitial lung disease 
INR 
international normalized ratio 
IRB 
institutional review board 

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Abbreviation 
Definition 
IV 
intravenous 
LAG-3 
lymphocyte activation gene 3 
LFT 
liver function test 
MATE1 or 2-K 
multidrug and toxin extrusion 1 or 2-K  
MedDRA 
Medical Dictionary for Regulatory Activities 
mCRC 
metastatic colorectal cancer 
MHC 
major histocompatibility complex 
MOA 
mechanism of action 
mRNA 
messenger ribonucleic acid 
MRP1 or 2 
multidrug resistance protein 1 or 2 
MUGA 
multigated acquisition 
NCCN 
National Comprehensive Cancer Network 
NCI 
National Cancer Institute 
NFAT 
nuclear factor of activated T cell 
NSCLC 
non-small cell lung cancer 
NYHA 
New York Heart Association 
OAT1 or 3 
organic anion transporter 1 or 3  
OATP1B1 or 1B3 
organic anion transporting polypeptide 1B1 or 1B3  
OCT1 or 2  
organic cation transporter 1 or 2 
ORR 
objective response rate 
OS 
overall survival 
PAM50 
Prosigna Breast Cancer Prognostic Gene Signature Assay 
pCR 
pathologic complete response 
PCS 
potentially clinically significant 
PD-1 
programmed cell death protein 1 
PD-L1 
programmed death-ligand 1 
PFS 
progression-free survival 
PK 
pharmacokinetic(s) 
PR 
progesterone receptor 
PRO 
patient-reported outcome 
PTFE 
polytetrafluorethylene 
PVG 
pharmacovigilance 

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Abbreviation 
Definition 
Q3W 
every 3 weeks 
RBC 
red blood cell 
RNA 
ribonucleic acid 
SAE 
serious adverse event 
SAP 
statistical analysis plan 
SC 
subcutaneous(ly) 
SCLC 
small cell lung cancer 
SDV 
source data verification 
SMC 
Safety Monitoring Committee 
SN 
severe neutropenia 
SOC 
standard of care 
SUSAR 
suspected unexpected serious adverse reactions 
T 
taxane 
TEAE 
treatment-emergent adverse event 
TGIT 
T cell Ig and ITIM domain 
TIL 
tumor-infiltrating lymphocyte 
TIM3 
T cell immunoglobulin and mucin domain 3 
TNBC 
triple negative breast cancer 
Treg 
regulatory T cell 
ULN 
upper limit of normal 
US 
United States 
WHO-DD 
World Health Organization Drug Dictionary 

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4. 
INTRODUCTION 
4.1. 
Triple Negative Breast Cancer  
Triple negative breast cancer (TNBC) is a heterogeneous disease with distinct pathological, 
genetic, and clinical features, and is associated with younger age and more advanced tumor stage 
at diagnosis, African American race/ethnicity, higher tumor grade, poor overall survival (OS), 
higher risk of disease recurrence, and higher recurrence in visceral organs within 5 years of 
diagnosis. Treatments which are effective for hormone receptor-positive breast cancer and 
human epidermal growth factor receptor 2 (HER2)-positive breast cancer, such as endocrine 
therapy or HER2-targeted therapies (e.g., trastuzumab), respectively, are not effective in TNBC, 
which lacks these markers. Neoadjuvant chemotherapy (systemic therapy given prior to 
definitive surgery) with an anthracycline/taxane-based chemotherapy regimen (e.g., AC/T 
chemotherapy) has been considered an important and standard part of the treatment strategy for 
patients with early-stage TNBC for both tumor control and improving the curability rate among 
subtypes (NCCN, 2021; Cardoso, 2019).  
Alternative neoadjuvant chemotherapy regimens such as those including carboplatin are 
available to patients with early-stage TNBC, however definite superiority of one regimen has not 
been demonstrated. The addition of carboplatin to paclitaxel in the neoadjuvant setting increased 
pathologic complete response (pCR) rates (von Minckwitz, 2014; Sikov, 2015); however, the 
disease-free survival (DFS) and OS effect with this treatment has not been confirmed and the 
addition of the platinum-based chemotherapy comes with additional toxicities. More recently, 
agents that target immune checkpoint pathways, such as the programmed cell death protein 1 
(PD-1)/programmed death ligand-1 (PD-L1) pathway, are in clinical development for TNBC, 
including in the neoadjuvant setting. Pembrolizumab is an anti-PD-1 monoclonal antibody, that 
has been approved for use in patients with metastatic TNBC with PD-L1 positive disease and 
recently for high-risk, early-stage TNBC in combination with chemotherapy as neoadjuvant 
treatment, and then continued as a single agent as adjuvant treatment after surgery (Keytruda® 
Prescribing Information, 2021). Results from the Phase 3 KEYNOTE-522 study demonstrated 
that the combination of pembrolizumab to standard neoadjuvant chemotherapy, including 
carboplatin, led to improved pCR rates and a statistically significant event-free survival (EFS) 
compared with chemotherapy alone in high-risk, early-stage TNBC patients regardless of PD-L1 
status (Schmid, 2020a; Merck Press Release, 2021). Ultimately, the neoadjuvant regimen 
selected for the individual patient will depend on patient characteristics and disease-specific 
factors.  
In summary, chemotherapy (with or without immunotherapy) remains the cornerstone in treating 
TNBC. However, toxicity and eventual treatment resistance are significant impediments to its 
success. Novel therapeutic options that can offer better anti-tumor efficacy without the 
associated high-grade toxicities are clearly needed for this patient population with high unmet 
medical need.  
4.1.1. 
T Cell Activity and the Tumor Microenvironment  
The importance of the types and crosstalk of immune cell populations within the tumor 
microenvironment and their impact on cancer progression has been clearly established. 
Accumulating evidence shows a correlation between tumor-infiltrating lymphocytes (TILs) in 

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tumor tissue and favorable clinical outcomes in various malignancies. In particular, the presence 
of cytotoxic cluster of differentiation 8 positive (CD8+) T cells and the ratio of cytotoxic CD8+ 
T cells to Forkhead Box P3 (FOXP3)+ regulatory T cells (Treg) correlates with improved 
prognosis and long-term survival in solid malignancies (Vasievich, 2011; Gonzalez, 2018). 
Another important factor in discerning the anti-tumor efficacy of the T cells within the tumor 
microenvironment is their activation and functional potential based on their exhaustion status. T 
cell exhaustion is a stepwise loss in function that develops in the setting of chronic stimulation 
and in the presence of an immunosuppressive environment. Exhausted T cells upregulate 
expression of inhibitory receptors including but not limited to PD-1, cytotoxic T lymphocyte 
associated protein 4 (CTLA-4), T cell immunoglobulin and mucin domain 3 (TIM3), T cell Ig 
and ITIM domain (TIGIT), and lymphocyte activation gene 3 (LAG-3), and through interaction 
with its ligand inhibits T cell activation. Thus, the development of therapeutic approaches that 
shift the tumor microenvironment to a more immune active environment is an active area of 
investigation, including in breast cancer. 
Relative to estrogen receptor (ER)-positive/HER2-negative breast cancer, TNBC tends to have 
higher mutational burden and increased potential neo-antigenicity which results in immune 
stimulation. The immune microenvironment in breast carcinoma has been largely defined by the 
presence and composition of TILs, which are most pronounced in TNBC and HER2-positive 
carcinomas (Cimino-Mathews, 2015). TILs are emerging as promising prognostic and predictive 
biomarkers in breast cancer as demonstrated by several studies in the neoadjuvant setting 
(Denkert, 2010; Ono, 2012; Yamaguchi, 2012). Analysis of pre-treatment and post-treatment 
tumor specimens from breast cancer patients showed a correlation between the development of 
TILs after neoadjuvant paclitaxel chemotherapy and clinical response (Demaria, 2001). As noted 
for other tumor types, among TIL subsets in breast cancer, the presence of cytotoxic CD8+ 
T cells is favorable, whereas the presence of the immunosuppressive suppressor FOXP3+ Tregs 
is unfavorable. There is evidence that a high CD8+/Treg ratio after neoadjuvant chemotherapy 
predicts OS and is associated with pCR (Ladoire, 2011; Park, 2020). Collectively, these data 
suggest that immunomodulatory therapies could be added to neoadjuvant chemotherapy to 
improve current treatment strategies for TNBC. 
Chemotherapy-induced immunosuppression and depletion of immune cells may also affect 
anti-tumor efficacy due to an inability of the host immune system to effectively mount a 
response against the cancer. Therefore, preserving the bone marrow and immune system from 
the cytotoxic effects of chemotherapy has the potential to maximize the anti-tumor activity of the 
chemotherapy while minimizing myelotoxicity. 
4.2. 
Trilaciclib  
Trilaciclib is a highly potent and selective, reversible, cyclin-dependent kinase (CDK) 4/6 
inhibitor that preserves hematopoietic stem and progenitor cells (HSPCs) as well as immune 
system function during chemotherapy (myeloprotection) in addition to directly enhancing 
anti-tumor immunity (anti-cancer efficacy) (Figure 1). In February 2021, the United States (US) 
Food and Drug Administration (FDA) approved trilaciclib (COSELA™) as a treatment to 
decrease the incidence of chemotherapy-induced myelosuppression in adult patients when 
administered prior to a platinum/etoposide-containing regimen or topotecan-containing regimen 
for extensive-stage small cell lung cancer (ES-SCLC). 

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Both HSPC and lymphocyte proliferation are dependent on CDK4/6 activity (Kozar, 2004; 
Malumbres, 2004; Ramsey, 2007; Horsley, 2008) and become arrested in the gap 1 (G1) phase of 
the cell cycle upon exposure to trilaciclib (He, 2017a). This trilaciclib-induced transient cell 
cycle arrest has been demonstrated to provide resistance to chemotherapy-induced cell damage 
by preventing HSPCs from proliferating in the presence of cytotoxic chemotherapy and 
favorably altering the tumor immune microenvironment through transient T cell inhibition when 
combined with chemotherapy (He, 2017b; Bisi, 2016; Lai, 2018; Sorrentino, 2017).  
Figure 1: 
Trilaciclib Transiently Arrests Normal Cells to Prevent Chemotherapy 
Induced Myelosuppression and Improve Anti-Tumor Efficacy 
 
G1=Gap 1; G2=Gap 2; HSPC=hematopoietic stem and progenitor cell; M=mitosis; S=synthesis 
Chemotherapeutic agents may elicit part of their anti-tumor efficacy by modulating the immune 
system to enhance antigen presentation, uptake, and processing; prime the immune response 
through immunodepletion; inhibit regulatory cells; and stimulate immune effector cells 
(Zitvogel, 2008; McDonnell, 2011; Bracci, 2014). Conversely, immunosuppression from direct 
cytotoxicity to the bone marrow and immune system over repeated cycles of chemotherapy may 
counterbalance the positive immunostimulatory effects of chemotherapy. Therefore, therapeutic 
approaches to maintain bone marrow health and immune system function should enhance the 
immune-mediated anti-tumor activity.  
Trilaciclib and other CDK4/6 inhibitors have been shown to augment anti-tumor responses in 
nonclinical settings (Klein, 2018) by enhancing T cell activation through the repression of 
nuclear factor of activated T cell (NFAT) phosphorylation (Deng, 2018), as well as increasing 
antigen presentation through upregulation of major histocompatibility complex (MHC) class I 
and II in CDK4/6-sensitive tumors and myeloid cells (Goel, 2017; Schaer, 2018). Additionally, 

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CDK4/6 inhibition can upregulate and stabilize the protein expression of PD-L1 on tumor cells 
(Zhang, 2018). Recently, nonclinical studies investigating CDK4/6 inhibitors in the 
differentiation of cytotoxic CD8+ T cells revealed a preferential skewing, of CDK4/6 inhibitor 
exposed cytotoxic CD8+ T cells, into memory precursor cells (Heckler, 2021). When these cells 
were transferred into mice, the CDK4/6 inhibitor exposed cytotoxic CD8+ T cells demonstrated 
durability and persistence. Importantly, mice administered with the CDK4/6 inhibitor-exposed 
T cells demonstrated protection following tumor challenge. Collectively, there is increasing 
pre-clinical evidence of a direct effect of CDK4/6 inhibition on immune cell activation and 
differentiation, thereby supporting the critical need to better understand the immunological 
effects of trilaciclib on the generation of an anti-tumor responses. 
4.2.1. 
Clinical Data with Trilaciclib in TNBC 
The use of trilaciclib for patients with TNBC was evaluated in Study G1T28-04, a global, 
multicenter, randomized, open-label, Phase 2 clinical study to evaluate the safety, efficacy, and 
pharmacokinetics (PK) of trilaciclib administered prior to gemcitabine/carboplatin (GC) therapy 
in patients with locally recurrent/metastatic TNBC who had previously been treated with 0 to 
2 lines of therapy in the metastatic setting. Patients were randomized 1:1:1 to one of two 
different trilaciclib + GC treatment regimens or GC alone. Based on its mechanism of action 
(MOA), it was hypothesized that trilaciclib administered before chemotherapy could protect the 
bone marrow from the cytotoxic effects of chemotherapy, while also enhancing immune activity 
in patients with TNBC, thus potentially improving both safety and anti-tumor activity. 
Additionally, TNBC is considered genomically unstable and the tumor microenvironment is 
moderately immunogenic (Park, 2018); a state that could be potentially enhanced by trilaciclib in 
combination with chemotherapy, leading to improved anti-tumor activity. 
The G1T28-04 study was the first evaluation of trilaciclib in a tumor type other than small cell 
lung cancer (SCLC), where trilaciclib development has focused on myeloprotection benefits 
(Section 4.4.2.1.1). In contrast to previously observed SCLC results, the addition of trilaciclib to 
chemotherapy for patients with TNBC in G1T28-04 did not result in statistically significant 
improvements in myeloprotection endpoints, but instead resulted in a substantial improvement in 
anti-tumor efficacy as measured by multiple anti-tumor efficacy endpoints including OS (median 
OS duration in control: 12.6 months vs. not evaluable or 17.8 months in the two trilaciclib 
groups; described in Section 4.4.2.1.1). Efficacy was demonstrated across patient subgroups, 
including patients with PD-L1 positive and negative tumors and those with different CDK4/6 
dependence signatures using two established assays (Prosigna Breast Cancer Prognostic Gene 
Signature Assay [PAM50] and Lehmann triple-negative breast cancer type) (Prat, 2014; 
Lehmann, 2016; Asghar, 2017). These data suggest trilaciclib does not antagonize chemotherapy 
efficacy irrespective of CDK4/6 status, TNBC is predominantly CDK4/6 independent, and 
therefore not sensitive to CDK4/6 inhibition (Tan, 2019; data on file). 
Evaluation of patient-reported outcomes (PROs) by the Functional Assessment of Cancer 
Therapy – Anemia and Functional Assessment of Cancer Therapy - Breast (FACT-B) indicated 
that patients treated with trilaciclib were less likely to have a deterioration in their symptoms, 
and in some cases had improvement in their symptoms, through the first 6 cycles of therapy; and 
that trilaciclib delayed deterioration of patient functioning and symptoms measures over time 
compared with GC alone. 

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4.2.2. 
T Cell Activity with Trilaciclib 
Nonclinical data demonstrate that trilaciclib enhances immune activation and promotes 
anti-tumor immunity by differentially arresting cytotoxic and regulatory T cell subsets followed 
by a faster recovery of cytotoxic T lymphocytes than Tregs in tumor (Section 4.4.1.1). To 
evaluate the effect of trilaciclib on T cell expansion in G1T28-04, T cell receptor was 
longitudinally sequenced from the peripheral blood. Simpson clonality significantly decreased 
over time in patients that received trilaciclib in addition to GC when compared to GC alone 
(Pinteraction=0.012) meaning that patients receiving trilaciclib and GC demonstrated T cell 
diversity based on increased numbers of T cell clones. Furthermore, when patients were stratified 
above or below median Simpson clonality at baseline, there was a trend for improved OS among 
patients with decreased peripheral clonality and a statistically significant improvement in OS 
among patients receiving trilaciclib (P=0.02) (O’Shaughnessy, 2020). In addition to a decrease in 
Simpson clonality, responders receiving trilaciclib prior to GC had more newly detected 
expanded clones compared with responders receiving GC alone (P=0.09; data on file). These 
data are consistent with the analyses of patient peripheral T cells from another clinical study 
(G1T28-02; NCT02499770) demonstrating that transient exposure of trilaciclib in patients with 
SCLC during chemotherapy treatment both preserved and increased peripheral lymphocyte 
counts and enhanced T cell activation (Lai, 2020). Other immune activating effects of CDK4/6 
inhibition have been demonstrated, including increasing antigen presentation through MHC 
class I, decreasing T cell exhaustion markers (e.g., PD-1, CTLA-4, and TIM3), stabilizing 
expression of PD-L1 on tumor cells, and increasing T cell effector function through high 
interferon (IFN)γ production. Collectively, these data provide insight into the variety of 
mechanisms by which trilaciclib enhances T cell immunity leading to an anti-tumor efficacy. In 
addition, nonclinical studies have suggested there is synergy between inhibition of CDK4/6 and 
anti-PD-1 blocking antibodies in multiple tumor models (Chaikovsky and Sage, 2018; 
Deng, 2018; Goel, 2017; Schaer, 2018; Lai, 2020; Bonelli, 2019; Teh and Aplin, 2019). Clinical 
data in SCLC demonstrated that the addition of trilaciclib prior to chemotherapy and the PD-L1 
antibody, atezolizumab, generated more newly expanded T cell clones with significantly greater 
expansion among patients with clinical response vs placebo (Daniel, 2020). Treatment with 
CDK4/6 inhibitors may increase the effectiveness of immune checkpoint blockade therapies or 
provide benefit in patients after progressing on immune checkpoint inhibitor (ICI) treatment.  
4.3. 
Study Rationale 
This study is designed to elucidate the immune-based MOA of trilaciclib independent of other 
treatments in a neoadjuvant setting of TNBC. Nonclinical and recent clinical studies with 
trilaciclib demonstrate enhanced immune activation and anti-tumor immunity through 
differentially arresting cytotoxic and regulatory T cell subsets followed by a faster recovery of 
cytotoxic T lymphocytes than Tregs in tumors. This differential alteration of cell cycle kinetics 
between cytotoxic T lymphocytes and Tregs results in a higher proportion of cytotoxic 
T lymphocytes than Tregs, enhancement of T cell activation, and a decrease in Treg-mediated 
immunosuppressive functions. Based on these anti-neoplastic driven effects on the immune 
response, the study is designed to define quantitative and qualitative changes in immune cell 
phenotype and function following neoadjuvant trilaciclib treatment. These include a 
measurement of cytotoxic CD8+ T cell infiltration into the tumor microenvironment following a 
single dose of trilaciclib and changes in ratio of cytotoxic CD8+ T cells to Tregs. Together, these 

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events promote the cytotoxic T lymphocyte-mediated clearance of tumor cells. Moreover, the 
anti-tumor effects of trilaciclib might result from the transient proliferative arrest of T cells 
(protecting them from chemotherapy-induced damage), followed by activation of cytotoxic 
T lymphocytes in the context of fewer Tregs.  
To evaluate the impact of trilaciclib on changes of the tumor-associated immune response in 
TNBC treated with standard of care (SOC) neoadjuvant chemotherapy (plus carboplatin and/or 
pembrolizumab per Investigator discretion), immunophenotypic changes will be compared in 
tumor biopsies at baseline, after a single dose of monotherapy trilaciclib, and at definitive 
surgery (if available). Serial peripheral blood collection will also be obtained in parallel with 
tumor sample collection to identify immune correlates associated with trilaciclib treatment. For 
peripheral blood, an extra timepoint will be collected prior to Cycle 2 Day 1 (C2D1) to define the 
kinetics of the immune response following trilaciclib plus chemotherapy. Longitudinal analysis 
after trilaciclib treatment will enable comprehensive assessment of the immune and 
anti-neoplastic MOA of trilaciclib with potential to identify biomarkers for patient selection in 
future studies and understand mechanisms of resistance. 
Finally, flexibility was built into the protocol to allow the Investigator to tailor neoadjuvant 
therapy to each patient. As the treatment paradigm for early-stage TNBC continues to evolve, 
platinum chemotherapy and immunotherapy may be added per Investigator discretion to the 
standard anthracycline/taxane-backbone. This inclusion will also provide additional safety and 
efficacy data for a novel combination.  
4.4. 
Background 
4.4.1. 
Summary of Nonclinical Data 
A brief summary of the trilaciclib nonclinical data is provided in the following sections. Detailed 
information is presented in the Trilaciclib Investigator’s Brochure (IB). 
Nonclinical data related to chemotherapy agents (doxorubicin, cyclophosphamide, paclitaxel, 
and carboplatin) and immunotherapy (pembrolizumab) are provided in the US prescribing 
information for each agent. 
4.4.1.1. 
Pharmacology Studies 
Through a structure-based design approach to optimize potency, selectivity, and drug 
metabolism and PK properties, G1 Therapeutics, Inc. identified trilaciclib as a highly potent 
inhibitor of CDK4 and CDK6 (half maximal inhibitory concentration values of 1 nM and 4 nM, 
respectively) that is highly selective for CDK4/Cyclin D1 versus CDK2/Cyclin E (>2500-fold 
selectivity). Trilaciclib also demonstrated reversible inhibition of CDK4/Cyclin D1, with an 
inhibition constant value of 0.78 nM. 
The trilaciclib-induced G1 arrest of HSPCs has been shown to be transient and readily reversible 
in both in vitro and in vivo models. In vivo analysis has demonstrated that trilaciclib 
administered prior to myelosuppressive chemotherapy leads to improved complete blood count 
(CBC) recovery of all blood lineages and increased survival. Specifically, in a model using the 
highly myelosuppressive chemotherapy 5-fluorouracil (5-FU), while the extent and duration of 
nadir in CBCs worsened after each cycle of 5-FU administered alone, trilaciclib administered 
prior to 5-FU ameliorated this worsening effect and the animals that received trilaciclib + 5-FU 

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demonstrated a faster rate of recovery of CBCs compared with the 5-FU alone group following 
Cycle 4 (He, 2017a).  
Nonclinical data have shown trilaciclib enhances immune activation and promotes anti-tumor 
immunity by differentially arresting cytotoxic and regulatory T cell subsets followed by a faster 
recovery of cytotoxic T lymphocytes than Tregs in tumors. Specifically, the addition of 
trilaciclib to various chemotherapy/ICI treatment combinations resulted in enhanced tumor 
growth delay and durability of the anti-tumor response. Trilaciclib favorably modulated the 
proliferation of T cell subsets in the tumor microenvironment, consistent with an enhanced 
cytotoxic T cell response (Figure 2; Lai, 2020). This differential alteration of cell cycle kinetics 
between cytotoxic T lymphocytes and Tregs results in a higher proportion of cytotoxic 
T lymphocytes than Tregs, enhancement of T cell activation, and a decrease in Treg-mediated 
immunosuppressive functions (Chaikovsky and Sage, 2018; Deng, 2018; Goel, 2017; 
Schaer, 2018). Together, these events promote the cytotoxic T lymphocyte-mediated clearance of 
tumor cells. Therefore, these data support the hypothesis that trilaciclib-mediated transient 
proliferative arrest of T cells (protecting them from chemotherapy-induced damage), followed by 
activation of cytotoxic T lymphocytes in the context of fewer Tregs led to the anti-tumor 
response observed.  
Nonclinical data have shown that in an extremely CDK4/6 dependent estrogen receptor positive 
breast cancer model, intermittent trilaciclib dosing during the time of chemotherapy treatment 
did not negatively affect chemotherapy treatment. The lack of antagonism when trilaciclib was 
added to chemotherapy treatment was observed in multiple CDK4/6 dependent models 
(Sorrentino, 2018).  
Figure 2: 
The Addition of Trilaciclib to Chemotherapy/Checkpoint Inhibitor 
Treatment Enhances Efficacy Through T Cell Activation 
 
 
CD=cluster of differentiation; PD-1=programmed cell death protein 1; PD-L1=programmed death-ligand 1; 
Treg=regulatory T cell.  

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4.4.1.2. 
Pharmacokinetic Studies 
Pharmacokinetic studies in rats and dogs showed that the relationship between dose level and 
plasma exposure to trilaciclib was generally similar between males and females and did not 
change with repeated daily dosing. Exposure to trilaciclib increased with dose level, but not 
always proportionally.  
In vitro analyses of direct and time-dependent inhibition suggest that drug interactions based on 
inhibition of cytochrome P450 (CYP)1A2-, 2B6-, 2C8-, 2C9-, 2C19-, and 2D6-mediated 
metabolic pathways are unlikely at clinical doses, however, the studies do suggest that drug 
interactions based on trilaciclib-mediated inhibition of CYP3A4-mediated metabolic pathways 
are possible, but clinical studies have confirmed no clinically significant drug-drug interaction 
(DDI) based on CYP3A (see Section 4.4.2.1.2 for additional details). Additionally, in vitro 
induction studies of the 3 major inducible CYP enzymes (CYP1A2, CYP3A4, and CYP2B6) in 
human hepatocytes suggest that trilaciclib-mediated induction is unlikely.  
In vitro inhibition studies with membrane transporter model systems also suggest trilaciclib is 
unlikely to cause a DDI based on inhibition of breast cancer resistance protein-, bile salt export 
pump-, organic anion transporter 1 (OAT1)-, organic anion transporter 3 (OAT3)-, organic anion 
transporting polypeptide 1B1 (OATP1B1)-, p-glycoprotein-, multidrug resistance protein 1 
(MRP1)-, multidrug resistance protein 2 (MRP2)-, or organic anion transporting polypeptide 1B3 
(OATP1B3)-mediated transport.  
However, in vitro, trilaciclib is a potent inhibitor of multidrug and toxin extrusion 1 (MATE1), 
multidrug and toxin extrusion 2-K (MATE2-K), organic cation transporter 1 (OCT1), and 
organic cation transporter 2 (OCT2) (see Section 4.4.2.1.2 for additional details).  
4.4.2. 
Summary of Clinical Data 
A brief summary of the trilaciclib clinical data is provided in the following sections. Detailed 
information is presented in the trilaciclib IB.  
4.4.2.1. 
Clinical Trials 
The safety and efficacy of administering trilaciclib prior to chemotherapy has been evaluated in 
one completed and one ongoing Phase 1b/2 study (G1T28-02 and G1T28-03) and two completed 
Phase 2 studies (G1T28-05 and G1T28-04) in patients with SCLC or TNBC. The Phase 2 
portions of Studies G1T28-02, G1T28-03, and Study G1T28-05 were randomized, double-blind 
and placebo-controlled. Study G1T28-04 was randomized and included a control arm but was 
not double-blinded.  
Additional studies that are ongoing include a Phase 3 study in metastatic colorectal cancer 
(mCRC; G1T28-207), a Phase 3 study in TNBC (G1T28-208); a Phase 2 study in urothelial 
carcinoma (G1T28-209), and a Phase 2 study in TNBC (trilaciclib + sacituzumab govitecan; 
G1T28-213).  
• Study G1T28-02 evaluated administration of either trilaciclib or placebo on Days 1 to 
3 of each 21-day etoposide plus carboplatin (E/P) chemotherapy cycle in patients with 
treatment naïve ES-SCLC. 

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• Study G1T28-03 evaluated administration of trilaciclib or placebo on Days 1 to 5 of 
each 21-day topotecan chemotherapy cycle in patients with previously treated 
ES-SCLC. 
• Study G1T28-05 evaluated administration of trilaciclib or placebo on Days 1 to 3 for 
a maximum of four 21-day cycles of Etoposide, carboplatin, and atezolizumab 
(E/P/A), followed by monotherapy atezolizumab, in patients with treatment naïve 
ES-SCLC. 
• Study G1T28-04 evaluated administration of trilaciclib prior to GC in patients with 
metastatic TNBC who had received 0 to 2 lines of previous therapy in the metastatic 
setting. Patients received 1) GC therapy only on Days 1 and 8 of a 21-day cycle, 
2) trilaciclib and GC once daily on Days 1 and 8 of each 21-day cycle, OR 
3) trilaciclib on Days 1, 2, 8 and 9 with GC on Days 2 and 9 of each 21-day cycle 
(further noted as Group 1, 2, or 3, respectively). 
• Study G1T28-207 (PRESERVE 1) is evaluating administration of either trilaciclib or 
placebo on Days 1 and 2 of each 14-day FOLFOXIRI/bevacizumab cycle in patients 
with proficient mismatch repair/microsatellite stable mCRC who have not received 
systemic therapy for metastatic disease. 
• Study G1T28-208 (PRESERVE 2) is evaluating administration of either trilaciclib or 
placebo on Day 1 and Day 8 of each 21-day GC cycle in patients receiving first line 
treatment for locally advanced unresectable/metastatic TNBC. 
• Study G1T28-209 (PRESERVE 3) is evaluating administration of trilaciclib on Day 1 
of each 21-day platinum-based chemotherapy cycle (4-6 cycles) followed by Day 1 of 
each 14-day avelumab maintenance cycle in patients receiving first-line treatment for 
advanced/metastatic urothelial carcinoma. 
• Study G1T28-213 is evaluating the administration of trilaciclib prior to sacituzumab 
govitecan-hziy on Day 1 and Day 8 of each 21-day cycle in patients with unresectable 
locally advanced or metastatic TNBC who received at least 2 prior treatments, at least 
1 in the metastatic setting. 
Based on data from the aforementioned SCLC trials, the US FDA approved trilaciclib 
(COSELA™) as a treatment to decrease the incidence of chemotherapy-induced 
myelosuppression in adult patients when administered prior to a platinum/etoposide-containing 
regimen or topotecan-containing regimen for ES-SCLC in February 2021. 
At the approved dose of 240 mg/m2, across all three SCLC studies, trilaciclib administered prior 
to chemotherapy statistically significantly reduced the duration of severe neutropenia (DSN) in 
Cycle 1 and occurrence of severe neutropenia (SN) (primary endpoints) compared with placebo. 
An integrated data analysis of the three SCLC studies (G1T28-02, G1T28-03, and G1T28-05) for 
8 of the most relevant myelosuppression endpoints (e.g., neutrophils, red blood cells [RBCs] and 
platelets) demonstrated statistically significant, and clinically meaningful, improvements for 
trilaciclib over available therapies in 6 of 8 endpoints across multiple lineages. Importantly, these 
myeloprotective benefits come with an overall improved safety profile compared with available 
therapy, as evidenced by reduced high grade treatment-emergent adverse events (AEs) across all 

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SCLC studies, and no detriment to anti-tumor efficacy results. For a more detailed description of 
the results, refer to the trilaciclib IB. 
4.4.2.1.1. Clinical Experience in TNBC 
Study G1T28-04 in patients with advanced TNBC did not meet its primary endpoint of 
myeloprotection (DSN in Cycle 1 and occurrence of SN), though a clinically meaningful benefit 
in OS was observed when trilaciclib was added to GC chemotherapy. The combination of 
trilaciclib and GC demonstrated a substantial improvement in anti-tumor efficacy as measured by 
OS (median OS duration [95% confidence interval (CI)] in control: 12.6 months [6.3, 15.6] vs. 
not evaluable [10.2, not evaluable] or 17.8 months [12.9, 32.7] in the two trilaciclib groups, 
respectively) and by progression-free survival (PFS) (median PFS [95% CI] in control 
5.7 months [3.3, 9.9] vs. 9.4 months [6.1, 11.9] or 7.3 months [6.2, 13.9] in the two trilaciclib 
groups, respectively) (Tan, 2019; O’Shaughnessy, 2020). The clinically meaningful anti-tumor 
efficacy results observed in G1T28-04 were noted across both of the trilaciclib treatment groups 
and in patients with both PD-L1 positive and negative tumors, and these benefits were observed 
for multiple anti-tumor efficacy endpoints, with objective response rate (ORR), PFS, and OS 
endpoints all showing numerical improvement with the addition of trilaciclib to GC compared 
with GC alone. These results were observed in the context of a control group that is reflective of 
published literature for this patient population. Furthermore, there were trends toward 
improvement in RBC and platelet-based measures as well as benefit in PRO endpoints. Given 
the encouraging evidence of improved anti-tumor activity as well as positive PROs observed in 
Study G1T28-04, a Phase 3 clinical trial designed to confirm the efficacy of trilaciclib 
administration prior to treatment with GC in TNBC patients receiving first- or second-line 
treatment for locally advanced unresectable/metastatic disease is currently ongoing (G1T28-208, 
PRESERVE 2). 
4.4.2.1.2. Pharmacokinetics 
The PK and clinical pharmacology of trilaciclib have been assessed in studies with healthy 
subjects, patients receiving chemotherapy (studies noted above), specific populations, and in 
DDI studies (see trilaciclib IB for details). 
Trilaciclib has a terminal half-life of approximately 14 hours and undergoes extensive 
metabolism. Mild hepatic impairment and mild and moderate renal impairment had no effect on 
trilaciclib exposure. Population PK analysis indicated that age, gender, weight and race had no 
clinically relevant effect on the systemic exposure of trilaciclib. For more information about PK 
profile of trilaciclib, please refer to the trilaciclib IB. 
A clinical DDI study in healthy subjects using the index CYP3A substrate midazolam indicated 
that trilaciclib had no impact on CYP3A activity and that the strong CYP3A inducer rifampin 
had no clinically meaningful effect on trilaciclib PK. Two clinical DDI studies using a strong 
CYP3A inhibitor itraconazole were also conducted. No clinically significant changes in exposure 
were observed for trilaciclib when co-administered with itraconazole. 
In an additional clinical DDI assessment in healthy subjects, concomitant use of trilaciclib 
increased metformin (OCT2, MATE1, and MATE-2K substrate) area under the plasma 
concentration-time curve from time zero to infinity (AUCinf) and maximum concentration by 
approximately 65% and 81%, respectively. Renal clearance of metformin was decreased by 37%. 

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There were no clinically significant differences in topotecan (MATE1 and MATE-2K substrate) 
pharmacokinetics when used concomitantly with trilaciclib. 
Trilaciclib is an inhibitor of OCT2, MATE1, and MATE-2K. Co-administration of trilaciclib 
may increase the concentration or net accumulation of OCT2, MATE1, and MATE-2K 
substrates in the kidney (e.g., dofetilide, dalfampridine, and cisplatin). Refer to the prescribing 
information for these concomitant medications for assessing the benefit and risk of concomitant 
use of trilaciclib. 
Table 2: 
Potentially Significant Drug Interactions with Trilaciclib 
Drugs 
Recommendations 
Comments 
Dofetilide 
The potential benefits of 
taking trilaciclib 
concurrently with dofetilide 
should be considered 
against the risk of QT 
interval prolongation. 
Increased dofetilide blood levels may occur in patients who 
are also receiving trilaciclib. Increased plasma concentrations 
of dofetilide may cause serious ventricular arrhythmias 
associated with QT interval prolongation, including torsade 
de pointes. 
Dalfampridine 
The potential benefits of 
taking trilaciclib 
concurrently with 
dalfampridine should be 
considered against the risk 
of seizures in these patients. 
Increased dalfampridine blood levels may occur in patients 
who are also receiving trilaciclib. Elevated levels of 
dalfampridine increase the risk of seizure.  
Cisplatin 
Closely monitor for 
nephrotoxicity.  
Concurrent treatment with trilaciclib may increase the 
exposure and alter the net accumulation of cisplatin in the 
kidney, which may associate with dose-related 
nephrotoxicity.  
 
Based on both nonclinical and clinical data, trilaciclib does not inhibit or induce any of the CYP 
enzymes. Therefore, the risk of a DDI with the concurrent anticancer medications used in this 
study (doxorubicin, cyclophosphamide, paclitaxel, carboplatin, and pembrolizumab) based on a 
CYP mechanism is minimal to nil. Trilaciclib is a known inhibitor of the drug transport proteins 
OCT2, MATE1, and MATE-2K; however, none of the concurrent anticancer medications used in 
this study are known substrates of these transporters. Therefore, the risk of a drug transporter 
based DDI is minimal to nil. 
4.4.3. 
Risks 
4.4.3.1. 
Trilaciclib 
Reproductive/embryo-fetal effects are an important potential risk of trilaciclib. Both nonclinical 
toxicology studies with trilaciclib, and clinical studies with other compounds with a similar 
MOA, report effects on either the reproductive system or embryo/fetus. Since this clinical study 
will focus on trilaciclib administered prior to cytotoxic chemotherapy (which carries its own risk 
of reproductive/embryo-fetal toxicity), the risks specific to trilaciclib are consistent with those 
experienced with chemotherapy. In addition, female patients will be required to have a negative 
pregnancy test prior to the first dose of study drug and will be monitored while on study. 
Eligibility criteria describing specific birth control methods are incorporated in the protocol and 

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the informed consent form (ICF). Dose discontinuation recommendations for female patients 
who become pregnant while receiving trilaciclib are also provided in the protocol 
(Section 11.3.7.5). Detailed information regarding all important identified and important 
potential risks of trilaciclib administration can be found in the trilaciclib IB. 
At the clinical dose of 240 mg/m2 being used in this study, trilaciclib did not have a clinically 
relevant effect on QTc (i.e., >10 msec).  
In an integrated safety analysis from the four Phase 2 oncology studies conducted with trilaciclib 
to date (G1T28-02 [complete], G1T28-03 [data cutoff: 31 May 2019], G1T28-05 [data cutoff: 
28 Jun 2019], and G1T28-04 [complete]), the most common treatment-emergent adverse events 
(TEAEs) (≥10%) that occurred more frequently in patients receiving trilaciclib compared with 
placebo were nausea, fatigue, headache, dyspnea, cough, hypokalemia, and infusion related 
reaction. Trilaciclib-related TEAEs occurring in ≥5% of patients with at least a ≥2% higher 
incidence in trilaciclib compared with placebo were nausea, fatigue, anemia, headache, infusion 
related reaction, neutrophil count decreased, decreased appetite, vomiting, and constipation. 
Adverse events of special interest (AESIs) identified for trilaciclib in the integrated safety 
summary are described below. Some AESIs have been infrequently reported (or not reported) in 
the trilaciclib clinical program to date but are considered to be potential class effects of CDK4/6 
inhibitors. However, as trilaciclib is given intravenously (IV) and only when chemotherapy is 
administered, the safety profile of trilaciclib appears to be different from that of the oral, 
chronically-dosed members of its pharmacologic class. All patients will be monitored for these 
events and dose modification and discontinuation guidelines are provided in Section 9.3. 
Trilaciclib AESIs: 
1. Injection Site Reaction/Phlebitis/Thrombophlebitis: Infusion of trilaciclib can cause 
injection-site reactions including phlebitis and thrombophlebitis. Injection-site reactions 
including phlebitis and thrombophlebitis occurred in 56 (21%) of 272 patients receiving 
trilaciclib in clinical trials, including Grade 2 (10%) and Grade 3 (0.4%) AEs. The 
median time to onset from start of trilaciclib was 15 days (range 1 to 542) and from the 
preceding dose of trilaciclib was 1 day (1 to 15). The median duration was 1 day (range 1 
to 151 for the resolved cases). Injection-site reactions including phlebitis and 
thrombophlebitis resolved in 49 (88%) of the 56 patients and led to discontinuation of 
treatment in 3 (1%) of the 272 patients. 
2. Acute Drug Hypersensitivity Reaction: Trilaciclib can cause acute drug 
hypersensitivity reactions, including facial edema and urticaria. Acute drug 
hypersensitivity reactions occurred in 16 (6%) of 272 patients receiving trilaciclib in 
clinical trials, including Grade 2 reactions (2%). One patient experienced a Grade 2 
anaphylactic reaction 4 days after receiving trilaciclib, which resolved with epinephrine, 
and treatment with trilaciclib was continued. The median time to onset from start of 
trilaciclib was 77 days (range 2 to 256) and from the preceding dose of trilaciclib was 
1 day (range 1 to 28). The median duration was 6 days (range 1 to 69 for the resolved 
cases). Acute drug hypersensitivity reactions resolved in 12 (75%) of the 16 patients. 
3. Pneumonitis/Interstitial Lung Disease (ILD): Severe, life-threatening, or fatal ILD 
and/or pneumonitis can occur in patients treated with CDK4/6 inhibitors, the same drug 
class as trilaciclib. ILD/pneumonitis occurred in 1 (0.4%) of 272 patients receiving 

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trilaciclib in clinical trials. The event was Grade 3 and reported 2 months after 
discontinuing trilaciclib, in a patient receiving a confounding medication. The event did 
not resolve.  
4. Hepatotoxicity: Both nonclinical toxicology studies with trilaciclib, and clinical studies 
with other compounds with a similar MOA, report reversible elevations in transaminases 
with continuous dosing. There has been only 1 instance of Grade 4 alanine 
aminotransferase (ALT) increase in a patient receiving trilaciclib, no Grade 4 aspartate 
aminotransferase (AST) increases, and no cases of Hy’s law reported in patients 
receiving trilaciclib. However, generally low grade and transient increases in AST, ALT, 
or bilirubin have been observed in a small number of patients (~5%) receiving trilaciclib 
prior to chemotherapy. Patients with mild hepatic impairment have been treated with 
trilaciclib without a clinically significant increase in exposure or the frequency/severity 
of AEs. 
5. Embolic and Thrombotic Events, Venous: The CDK4/6 inhibitor abemaciclib has been 
associated with an increased risk for venous thromboembolism when combined with 
endocrine therapy in patients with breast cancer. This same risk has not been reported for 
the other approved oral CDK4/6 inhibitors (ribociclib and palbociclib); therefore, it is not 
clear if this is a class effect. Approximately 3% of cancer patients that received trilaciclib 
prior to chemotherapy experienced a venous thromboembolic event and half of those 
events (3/6) were Grade 3 or 4. No Grade 5 events were reported. Approximately 2% of 
patients receiving chemotherapy alone or with placebo reported an embolic or thrombotic 
event, 1 of 3 such events was Grade 3. 
4.4.3.2. 
Doxorubicin, Cyclophosphamide, and Paclitaxel  
4.4.3.2.1. Doxorubicin 
Per the boxed warning in the prescribing information for doxorubicin, the following are 
important risks related to doxorubicin use: 
• Cardiomyopathy: Myocardial damage can occur with doxorubicin hydrochloride with 
incidences from 1% – 20% for cumulative doses from 300 mg/m2 to 500 mg/m2 when 
doxorubicin hydrochloride is administered every 3 weeks. The risk of 
cardiomyopathy is further increased with concomitant cardiotoxic therapy.  
• Secondary Malignancies: Secondary acute myelogenous leukemia and 
myelodysplastic syndrome occur at a higher incidence in patients treated with 
anthracyclines, including doxorubicin hydrochloride.  
• Extravasation and Tissue Necrosis: Extravasation of doxorubicin hydrochloride can 
result in severe local tissue injury and necrosis requiring wide excision and skin 
grafting.  
• Severe myelosuppression resulting in serious infection, septic shock, requirement for 
transfusions, hospitalization, and death may occur.  

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Per the Warnings and Precautions in the prescribing information for doxorubicin, the following 
are important risks related to doxorubicin use: 
• Radiation-Induced Toxicity: Can be increased by the administration of Doxorubicin 
Hydrochloride Injection. Radiation recall can occur in patients who receive 
Doxorubicin Hydrochloride Injection after prior radiation therapy. 
• Embryo-Fetal Toxicity: Can cause fetal harm.  
In addition, the most common (>10%) adverse reactions observed following doxorubicin 
treatment are alopecia, nausea, and vomiting. 
4.4.3.2.2. Cyclophosphamide 
Per the Warnings and Precautions in the prescribing information for cyclophosphamide, the 
following are important risks related to cyclophosphamide use: 
• Myelosuppression, Immunosuppression, Bone Marrow Failure, and Infections: 
Severe immunosuppression may lead to serious and sometimes fatal infections.  
• Urinary Tract and Renal Toxicity: Hemorrhagic cystitis, pyelitis, ureteritis, and 
hematuria can occur.  
• Cardiotoxicity: Myocarditis, myopericarditis, pericardial effusion, arrhythmias, and 
congestive heart failure, which may be fatal, have been reported.  
• Pulmonary Toxicity: Pneumonitis, pulmonary fibrosis and pulmonary veno-occlusive 
disease leading to respiratory failure may occur.  
• Secondary malignancies  
• Veno-occlusive Liver Disease: Fatal outcome can occur.  
• Alcohol Content: The alcohol content in a dose of Cyclophosphamide Injection may 
affect the central nervous system. This may include impairment of a patient’s ability 
to drive or use machines immediately after infusion. 
• Embryo-Fetal Toxicity: Can cause fetal harm. 
In addition, adverse reactions reported most often include neutropenia, febrile neutropenia, fever, 
alopecia, nausea, vomiting, and diarrhea. 
4.4.3.2.3. Paclitaxel 
Per the boxed warning in the prescribing information for paclitaxel, the following are important 
risks related to paclitaxel use: 
• Anaphylaxis and severe hypersensitivity reactions characterized by dyspnea and 
hypotension requiring treatment, angioedema, and generalized urticaria have occurred 
in 2 to 4% of patients receiving paclitaxel in clinical studies. Fatal reactions have 
occurred in patients despite premedication.  
• Bone marrow suppression (primarily neutropenia) is dose-dependent and is the 
dose-limiting toxicity. 

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Per the Warnings and Precautions in the prescribing information for paclitaxel, the following are 
also important risks related to paclitaxel use: 
• Severe conduction abnormalities have been documented in <1% of patients during 
paclitaxel therapy and in some cases requiring pacemaker placement.  
• Embryo-Fetal Toxicity: Can cause fetal harm. 
In addition, adverse reactions reported most often include neutropenia, thrombocytopenia, 
anemia, nausea, vomiting, diarrhea, infections, and mucositis. 
4.4.3.3. 
Treatment per Investigator Discretion: Carboplatin and Pembrolizumab 
4.4.3.3.1. Carboplatin 
Per the boxed warning in the prescribing information for carboplatin, the following are important 
risks related to carboplatin use: 
• Bone marrow suppression is dose related and may be severe, resulting in infection 
and/or bleeding. Anemia may be cumulative and may require transfusion support. 
• Vomiting is another frequent drug-related side effect. 
• Anaphylactic-like reactions to carboplatin injection have been reported and may 
occur within minutes of carboplatin injection administration.  
Per Warnings and Precautions in the prescribing information for carboplatin, the following are 
additional important risks related to carboplatin use: 
• Nephrotoxic potential: concomitant treatment with aminoglycosides has resulted in 
increased renal and/or audiologic toxicity  
• Peripheral neurotoxicity: observed infrequently, but its incidence is increased in 
patients older than 65 years and in patients previously treated with cisplatin  
• Loss of vision 
• Abnormal liver function tests (LFTs) 
• Fetal harm 
The most common adverse reactions with carboplatin in combination are thrombocytopenia, 
neutropenia, leukopenia, anemia, nausea, vomiting, other gastrointestinal effects, central 
neurotoxicity, serum glutamic oxaloacetic transaminase elevations, alkaline phosphatase 
elevations, hypomagnesemia, pain, asthenia, and alopecia. 

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4.4.3.3.2. Pembrolizumab 
Per Warnings and Precautions in the prescribing information for pembrolizumab, the following 
are important risks related to pembrolizumab use: 
• Immune-mediated adverse reactions 
• Infusion-related reactions 
• Complications of allogeneic hematopoietic stem cell transplantation 
• Fetal harm 
The most common adverse reactions with pembrolizumab in combination with chemotherapy are 
fatigue/asthenia, nausea, constipation, diarrhea, decreased appetite, rash, vomiting, cough, 
dyspnea, pyrexia, alopecia, peripheral neuropathy, mucosal inflammation, stomatitis, headache, 
and weight loss. 
4.4.3.4. 
Tumor Biopsy Collection 
Risks associated with tumor biopsy may include: stinging pain from injection of local aesthetic; 
pain or discomfort from the biopsy procedure; bleeding, swelling, scarring, soreness, or bruising; 
infection of wound; and contamination of cancer cells to unaffected tissue when removing 
biopsy needle. 
4.5. 
Benefit/Risk Assessment 
Clinical trials are designed to provide information about the safety and effectiveness of an 
investigational medicine which may not always provide direct benefit to the patients 
participating in the trial. In this study, it is unknown whether patients will receive additional 
benefit above that of SOC with the addition of trilaciclib. Potential benefits of trilaciclib are 
addressed in Section 4.4.2. Completed studies with trilaciclib have demonstrated a manageable 
safety profile in combination with several different chemotherapy regimens. Though trilaciclib 
has not been fully evaluated with an anthracycline/taxane chemotherapy regimen to date, the 
risks of AC/T (with and without carboplatin) are well documented. In particular, trilaciclib is not 
associated with significant cardiac risks, unlike anthracyclines which carry a risk of 
cardiomyopathy. There are no known risks of DDI with trilaciclib and these chemotherapy 
agents nor pembrolizumab. In Study G1T28-04, the rates of overall toxicity were comparable in 
patients who received trilaciclib with GC versus GC alone despite the 2-fold increase in the 
median number of cycles and 50% increase in the cumulative dose of both gemcitabine and 
carboplatin in patients who received trilaciclib. Rates of discontinuation due to an AE were not 
different between the trilaciclib groups and the GC alone group. PRO data also suggested that 
patients on trilaciclib (compared with GC alone) had a better experience receiving 
chemotherapy. Finally, efficacy in Study G1T28-04 demonstrated a clinically meaningful benefit 
in OS and PFS when trilaciclib was added to GC. A coronavirus disease (COVID)-19 risk 
assessment has been performed, documented, and will be provided as a separate document. 
Additional details regarding specific benefits and risks for patients participating in this clinical 
trial may be found in the trilaciclib IB and informed consent documents. 

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5. 
OBJECTIVES AND ENDPOINTS 
The primary, secondary, and exploratory objectives of this study and their associated endpoints, 
for patients with TNBC, are presented in Table 3. 
Table 3:  
Objectives and Endpoints  
Objectives 
Endpoints 
Primary Objective 
• 
To evaluate the immune-based 
mechanism of action of trilaciclib after a 
single-dose as measured by the change in 
CD8+ TILs/Treg ratio in tumor tissue 
• 
Change in CD8+ TILs/Treg ratio in tumor tissue from 
baseline to 7 days after single-dose monotherapy trilaciclib 
administration  
Secondary Objectives 
• 
To assess the pCR rate at the time of 
definitive surgery  
• 
Rate of pCR using the definition of ypT0/Tis ypN0 (i.e., no 
invasive residual tumor in breast or nodes; noninvasive 
breast residuals allowed) as assessed by the local pathologist 
• 
To evaluate the safety and tolerability of 
trilaciclib in combination with standard 
neoadjuvant systemic therapies  
• 
Safety/tolerability as per CTCAE version 5.0 
Exploratory Objectives 
• 
To characterize the intratumoral immune 
profile following trilaciclib  
• 
Immune-specific RNA profiling of tumor tissue at baseline, 
7 days after single-dose monotherapy trilaciclib 
administration, and at surgery as quantified by CD8+ T cell 
and Treg infiltration  
• 
To evaluate the kinetics of the peripheral 
immune response following trilaciclib  
• 
Longitudinal immune changes in peripheral blood, 
measured by frequency of immune subsets and profiling of 
activation, maturation, and exhaustion status 
• 
Ex-vivo measurement of cytokine production to determine 
T cell function and polyfunctionality 
• 
To identify molecular and cellular 
biomarkers in tumor or blood samples 
that may be indicative of clinical 
response/resistance, pharmacodynamic 
activity, and/or the mechanism of action 
of trilaciclib and other systemic 
treatments 
• 
pCR in patients by subgroups (e.g., CDK4/6 dependence 
signatures: CDK4/6 dependent, CDK4/6 independent, 
CDK4/6 indeterminate; PD-L1 status as measured by IHC: 
positive, negative) 
• 
pCR in patients by gene signatures identified in the tumor at 
baseline 
• 
pCR in patients by frequency of immune subsets, 
immunological markers, and cytokines 
CD8+=cluster of differentiation 8 positive; CDK=cyclin dependent kinase; CTCAE=Common Terminology Criteria 
for Adverse Events; IHC=immunohistochemistry; pCR=pathologic complete response; PD-L1=programmed death-
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6. 
INVESTIGATIONAL PLAN 
6.1. 
Overall Study Design 
This is a Phase 2, multicenter, open-label, single-arm, neoadjuvant study with 4 phases: 
1) Screening Phase, 2) Trilaciclib Lead-In Phase, 3) Treatment Phase, and 4) Surgery and 
Follow-Up Phase. A study schema is provided in Figure 3. A total of approximately 30 patients 
will be enrolled in the study. 
During the Screening Phase, tumor tissue (sample #1) will be obtained at baseline prior to any 
study drug. This sample may be archival tissue, or if unavailable/insufficient, then a fresh biopsy 
is required. Patients with adequate archival tissue will also have the option to provide a fresh 
biopsy at baseline. Patients will receive a single dose of monotherapy trilaciclib 240 mg/m2 in 
the Trilaciclib Lead-In Phase, followed by tumor biopsy (sample #2) 7 (±1) days later. Following 
the biopsy, patients will enter the Treatment Phase in which trilaciclib 240 mg/m2 on Day 1 of 
each cycle will be administered along with dose-dense anthracycline/cyclophosphamide 
followed by weekly taxane chemotherapy (doxorubicin 60 mg/m2 + cyclophosphamide 
600 mg/m2 [AC] every 2 weeks for 4 cycles [Cycles 1-4], then weekly paclitaxel [T] 80 mg/m2 
weekly for 12 cycles [Cycles 5-16]). If pembrolizumab is given (per Investigator discretion), it 
will start with AC (Cycle 1 of chemotherapy). If carboplatin is given (per Investigator discretion) 
it will start with paclitaxel (Cycle 5). 
Growth factors (e.g., granulocyte colony stimulating factor [G-CSF]) should be administered 
after each cycle of AC chemotherapy and/or per Investigator discretion. Premedications will be 
given in accordance with local institutional guidelines.  
Treatment cycles will occur consecutively without interruption, except when necessary to 
manage toxicities or for administrative reasons. There should be no more than 4 weeks between 
doses of chemotherapy. Dosing delays >4 weeks may be permitted on a case-by-case basis with 
the approval of the Investigator and Medical Monitor. Criteria which patients must meet in order 
to receive study drug on Day 1 are provided in Section 9.2. 
Three to 5 weeks after the last dose of chemotherapy, patients will proceed to definitive surgery 
at which time tumor tissue (sample #3) will be collected if the patient has residual disease. A 
30-day Safety Follow-up Visit will occur 30 (+7) days after last dose of trilaciclib and an End of 
Study Visit will occur within 14 days after surgery. Both the Safety Follow-up Visit and End of 
Study Visit may be conducted in person or by telephone and may occur at the same visit.  
Tumor and blood collection is detailed in Section 11.2. A Safety Monitoring Committee (SMC) 
will monitor accumulating data throughout the study on a regular basis, as described in 
Section 11.4. The study will be completed when the criteria outlined in Section 10.4 have been 
met, or upon Sponsor termination of the study. 
 

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Figure 3:  
Study Schema 
 
AC=doxorubicin/cyclophosphamide; C=cycle; Cb=carboplatin; D=day; Mono=monotherapy; Pembro=pembrolizumab; Q3W=every 3 weeks; QW=every week; 
SOC=standard of care; T=paclitaxel; TNBC=triple-negative breast cancer; Trila=trilaciclib; Tx=treatment 

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6.2. 
Rationale for the Primary Endpoint 
Clinically meaningful anti-tumor efficacy results were observed in G1T28-04 in patients with 
advanced TNBC and were noted across multiple endpoints, including OS, PFS, and ORR. These 
results are currently being evaluated further in a Phase 3 study in advanced TNBC patients 
(G1T28-208; PRESERVE 2). However, the MOA of trilaciclib in TNBC is not completely 
understood and much remains to be learned regarding how best to leverage trilaciclib in treating 
patients. Earlier pre-clinical and translational data from SCLC studies demonstrate an 
enhancement of both CD4+ and CD8+ T cell proliferation following trilaciclib treatment 
(Lai, 2020). Specifically, trilaciclib-exposed T cells were able to withstand Treg suppression and 
proliferate, and longitudinal assessment of splenic T cell proliferation in trilaciclib treated mice, 
demonstrated a peak response of 4 days for CD8+ T cells and 7 days for CD4+ T cells. 
Additionally, in SCLC patients treated with trilaciclib, the ratio of CD8+/Tregs increased over 
time suggesting an increase in CD8+ T cell proliferation and/or depletion of Tregs in circulation. 
Based on these changes in the immune response during the course of trilaciclib treatment, the 
endpoints for this study are to measure cytotoxic CD8+ T cell infiltration in the tumor 
microenvironment and to quantitate the changes in cytotoxic CD8+ T cell/Tregs 7 days post 
single dose monotherapy trilaciclib (and prior to any chemotherapy/immunotherapy). Seven days 
was selected as the optimal timepoint for evaluating the immune MOA of trilaciclib based on 
parallel assessment of TILs in checkpoint blockade therapies (Kim, 2019; Choe, 2019). 
Collectively, the primary endpoint for this study will provide insight into the trilaciclib-specific 
effect on the generation of an anti-tumor T cell response.  
6.3. 
Rationale for Tumor Biopsy Collection 
Nonclinical data and data from samples of patients treated with trilaciclib suggest that the MOA 
of trilaciclib involves enhancement of immune activation and promotes anti-tumor immunity by 
differentially arresting cytotoxic and regulatory T cell subsets followed by a faster recovery of 
cytotoxic T lymphocytes than Tregs in tumor (See Section 4.1.1 and Section 4.4.1.1). The 
immune system is a network of dynamic players that are interdependent and is therefore difficult 
to capture in a single snapshot. Access to tumor tissue before, during, and after trilaciclib will be 
critical in understanding the immune response of trilaciclib and the complex interactions within 
the tumor microenvironment. This study will enable comprehensive analysis of biomarker 
endpoints and correlation with clinical activity, thus providing important insights into the 
immune, anti-neoplastic MOA of trilaciclib, identifying biomarkers for patient selection in future 
studies, and elucidating mechanisms of resistance to trilaciclib treatment. 
Longitudinal tissue-based studies will be evaluated at 3 time points. Baseline tumor samples will 
provide initial immune features including PD-L1 expression and quantitation of cytotoxic CD8+ 
T cells and Tregs in untreated tumors which may be predictive of treatment response. 
Subsequent tumor samples will be analyzed similarly to discern dynamic changes during the 
course of therapy. Several studies have demonstrated that monitoring on-treatment tumor 
immune response via paired biopsies is more predictive of treatment outcome than immune 
features observed in only baseline samples (Lesterhuis, 2017; Park, 2020). The 7-day post 
trilaciclib timepoint is supported by studies with anti-PD-1 therapy showing peak cytotoxic 
CD8+ T cell proliferation in blood samples approximately 7 days post initial treatment and are 

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predictive of response (Huang, 2019; Kim, 2019). Overall, assessment of tumor biopsies will 
provide an immune analysis that is more reflective of the localized tumor immune environment. 
6.4. 
Rationale for Peripheral Blood Collection 
Longitudinal blood-based studies will provide a correlative assessment of the immune response 
during the course of the study. Unlike biopsy collection, blood samples are less invasive to 
obtain, can be collected more frequently, and provide a significant number of cells for 
multi-analysis. Blood will be collected at the same time points as tumor biopsy collection plus an 
additional time point at C2D1 of trilaciclib plus chemotherapy. All blood samples will be 
analyzed via mass spectrometry for immune profiling and flow cytometry for functional 
assessment via the measurement of cytokine production.  
6.5. 
Rationale for Dose and Schedule of Trilaciclib 
Previous studies demonstrated the recommended phase 2 dose of trilaciclib was 240 mg/m2, and 
this dose is now approved by the US FDA for patients with SCLC. When trilaciclib was 
administered prior to chemotherapy to cancer patients, doses of 200 mg/m2 (rounded up from 
192 mg/m2), 240 mg/m2, and 280 mg/m2 were evaluated. Trilaciclib exposures in cancer patients 
were slightly lower compared with healthy subjects, such that the dose of 240 mg/m2 (rather than 
200 mg/m2) more closely matched the biologically effective dose of 192 mg/m2. In addition, the 
dose of 240 mg/m2 demonstrated maximal myeloprotection efficacy benefits (compared with 
200 mg/m2 and 280 mg/m2) as measured by a variety of myeloprotection endpoints. The 
myeloprotective effect at 240 mg/m2 was further evaluated and confirmed in three randomized 
controlled Phase 2 studies in SCLC patients. See the trilaciclib IB for details.  
In all studies enrolling cancer patients, trilaciclib is always administered prior to systemic 
chemotherapy on each day of chemotherapy administration. Trilaciclib shall not be administered 
as monotherapy (i.e., on days that chemotherapy will be delayed) except for a single dose during 
the Trilaciclib Lead-In Phase, which will be used to evaluate changes in the tumor 
microenvironment prior to beginning the chemotherapy regimen. 
6.6. 
Rationale for Patient Population 
Among all breast cancer subtypes, TNBC has the worst prognosis and limited treatment options. 
Due to lack of specific molecular targets, treatment of TNBC has been relying on chemotherapy, 
in particular, anthracycline and taxane combinations. In light of the positive impact on OS 
duration observed in Study G1T28-04, as well as trilaciclib’s manageable safety profile and 
improvement in PRO and myeloprotection endpoints, trilaciclib has the potential to add to the 
armamentarium of treating TNBC, an area of high unmet medical need. As such, better 
understanding of the immune mechanism of trilaciclib is greatly warranted.  

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6.7. 
Rationale for Neoadjuvant Therapy in TNBC and Secondary pCR 
Endpoint  
Neoadjuvant therapy is an important and standard treatment strategy for patients with locally 
advanced TNBC as it increases the likelihood of tumor resectability and breast conservation and 
has a positive and significant correlation of pCR with long-term clinical benefit and OS 
(Liedtke, 2008). Early prospective observational studies evaluating outcome of neoadjuvant 
chemotherapy in different breast cancer subtypes revealed that TNBC was more chemosensitive 
compared with non-TNBC subtypes such as ER-positive, HER2-negative (luminal), with 
substantially increased pCR rate and clinical response rate. However, as a group, patients with 
TNBC had a poorer prognosis with significantly higher disease recurrence rate and lower 
survival rate. The poor long-term outcome in TNBC was found to be driven by those who did not 
achieve pCR after neoadjuvant chemotherapy (FDA, 2014; EMA, 2014). Patients who achieved 
pCR demonstrated sustained clinical benefit regardless of breast cancer subtypes (Carey, 2007; 
Liedtke, 2008).A large, pooled analysis demonstrated patients who attain pCR, when defined as 
no tumor in both breast and lymph nodes (ypT0 ypN0 or ypT0/is yp N0), have improved 
survival, with the strongest association observed in patients with TNBC (Cortazar, 2014).  
6.8. 
Rationale for Anthracycline/Taxane-Based Chemotherapy  
Per current National Comprehensive Cancer Network (NCCN) guidelines, dose-dense AC 
(doxorubicin/cyclophosphamide) followed by paclitaxel is a preferred regimen for neoadjuvant 
therapy for HER2-negative breast cancer patients. Addition of a taxane to an anthracycline-based 
regimen as adjuvant chemotherapy has been shown to improve both DFS and OS in locally-
advanced breast cancer (De Laurentiis, 2008). The pCR rate for paclitaxel followed by an 
anthracycline and cyclophosphamide is about 30% (von Minckwitz, 2011).  
The optimal schedule of paclitaxel was evaluated in the Eastern Cooperative Oncology Group 
(ECOG) E1199 trial in which neoadjuvant paclitaxel every 3 weeks for 4 cycles was compared 
to weekly for 12 cycles (Sparano, 2015). Weekly paclitaxel improved DFS and OS in the TNBC 
subset compared with the every 3 week paclitaxel arm. Weekly paclitaxel was also used as part 
of the chemotherapy backbone in the CALGB40603 and GeparSixto trials. As such, dose-dense 
AC followed by weekly paclitaxel was chosen as the treatment regimen in this neoadjuvant 
study.  
To date, trilaciclib has demonstrated a manageable safety profile in combination with various 
chemotherapy agents, including gemcitabine, carboplatin, etoposide, and topotecan. 
Furthermore, the Phase 2 adaptive I-SPY2 study (NCT01042379) has included a study arm to 
evaluate the safety and efficacy of trilaciclib in combination with neoadjuvant paclitaxel (80 
mg/m2 weekly) followed by doxorubicin (60 mg/m2) and cyclophosphamide (600 mg/m2) every 
2 or 3 weeks in locally advanced breast cancer. Data from this study are pending. 
6.9. 
Rationale for Pembrolizumab (per Investigator Discretion) 
Pembrolizumab functions as an immune checkpoint blockade by targeting PD-1, which helps to 
restore endogenous anti-cancer immunity. Pembrolizumab has shown significant clinical 
anti-cancer activity across multiple tumor types including melanoma, NSCLC, head and neck 

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cancer, bladder cancer and has gained FDA approval for treating early-stage and advanced 
TNBC, melanoma, head and neck cancer, and NSCLC. 
Support for the use of PD-1/PD-L1 inhibition is provided by a recent meta-analysis which found 
that the addition of PD-1/PD-L1 blockade to neoadjuvant chemotherapy significantly improves 
pCR rates in TNBC patients (Tarantino, 2021). In an earlier Phase 1b study, pembrolizumab in 
combination with different chemotherapy regimens as neoadjuvant treatment for high-risk, 
early-stage TNBC resulted in pCR rates of 60% across all groups (Schmid, 2020b). These data 
are further supported by the ongoing Phase 3 study, KEYNOTE-522, which showed a higher 
pCR rate and improvement in EFS when pembrolizumab was added to standard neoadjuvant 
chemotherapy, regardless of disease PD-L1 status (Schmid, 2020a; Merck Press Release, 2021). 
Longer follow-up of the ongoing clinical trials is needed to confirm whether the increased in 
pCR rate will translate into a meaningful survival benefit. 
Based on nonclinical studies, CDK4/6 inhibitors have been shown to enhance anti-tumor T cell 
activity through stabilization of PD-L1 expression on tumor cells, resulting in increased 
sensitivity to ICI, such as the PD-1 or PD-L1 monoclonal antibodies (Lai 2020; Deng 2018). 
Further, the addition of trilaciclib to chemotherapy/ICI combination has been shown to enhance 
the anti-tumor response (Lai 2020). Collectively, these nonclinical data support the combination 
of CDK4/6 inhibitors like trilaciclib with ICI. In the clinical setting, trilaciclib was well tolerated 
when given prior to induction treatment with the PD-L1 antibody, atezolizumab and 
etoposide/carboplatin (E/P/A) in patients with SCLC (Daniel, 2020). Compared with placebo, 
fewer patients treated with trilaciclib in combination with E/P/A experienced serious AEs and 
Grade 3 or Grade 4 AEs, mainly due to fewer hematologic events.  
In this study, pembrolizumab can be given per Investigator discretion if deemed the best option 
for the patient at the dose level of 400 mg every 6 weeks. Though the dose level in 
KEYNOTE-522 was 300 mg every 3 weeks (Q3W), the FDA granted accelerated approval to the 
400 mg every 6 week regimen based on PK modeling, safety, and exposure-response analyses in 
the Study KEYNOTE-555. In light of these data and convenience with the dose-dense AC and 
weekly paclitaxel schedule, the every 6 week dosing schedule for pembrolizumab was chosen for 
this study (Keytruda® Prescribing Information, 2021).  
6.10. 
Rationale for Carboplatin (per Investigator Discretion) 
Neoadjuvant carboplatin in combination with weekly paclitaxel at 80 mg/m2 versus paclitaxel 
alone followed by the standard anthracycline/cyclophosphamide combination has shown 
increased pCR rates in patients with TNBC via 2 randomized trials using either weekly 
carboplatin at AUC 2 (the Phase II GeparSixto trial; von Minckwitz, 2014), or carboplatin at 
AUC 6 Q3W (the Phase III CALGB 40603 trial; Sikov, 2015). Due to toxicity, in the GeparSixto 
trial, the dose of carboplatin was reduced to AUC 1.5. A meta-analysis of 1,598 TNBC patients 
treated with platinum-based neoadjuvant chemotherapy demonstrated a pCR of 45%, with a 
significantly increased rate of pCR in those treated with platinum therapy vs. nonplatinum agents 
(risk ratio 1.45 (95% CI, 1.25 -1.68, p<0.0001; Petrelli, 2014). It is worth noting that in the 
CALGB 40603 study the carboplatin AUC6 Q3W plus weekly paclitaxel 80 mg/m2 arm showed 
statistically significant increase in Grade 3/4 neutropenia (56% vs. 22%) and Grade 3/4 
thrombocytopenia (20% vs. 4%) compared to paclitaxel alone arm. Taken together, the use of 
carboplatin in the neoadjuvant setting may provide benefit to some patients (as evidenced by 

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pCR); however, the survival effect has not been confirmed and platinum-based therapies come 
with additional hematologic and neurologic toxicities to consider.  
Carboplatin (with gemcitabine) has been studied in combination with trilaciclib in the Phase 2 
study G1T28-04 in locally recurrent/metastatic TNBC patients (see Section 4.4.2). A total of 
68 patients were exposed to both carboplatin and trilaciclib in this study. Despite a longer 
duration of chemotherapy in the trilaciclib groups, Grade 3 and 4 hematologic toxicities 
associated with chemotherapy were reported at a similar frequency in patients with and without 
trilaciclib (Tan, 2019). As such, it is possible that the myeloprotective effects of trilaciclib may 
lessen the hematologic toxicities well documented with carboplatin. 
In this study, carboplatin may be administered per Investigator discretion. The decision to add 
carboplatin should be made by the first dose of paclitaxel. The option to add pembrolizumab and 
carboplatin are exclusive of one another.  

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7. 
STUDY POPULATION 
Prospective approval of protocol deviations to recruitment and enrollment criteria, also known as 
a protocol waiver or exemption, is not permitted. 
7.1. 
Inclusion Criteria 
Patient eligibility should be reviewed and documented by an appropriately qualified member of 
the Investigator study team before patients are included in the study. Patients must meet all of 
the following inclusion criteria to be eligible for enrollment into the study: 
1. Treatment-naïve early-stage breast cancer in which neoadjuvant chemotherapy with an 
anthracycline/taxane combination is deemed to be a suitable therapy and patient intends 
to undergo curative surgery 
2. Females ≥ 18 years of age  
3. Documented diagnosis of estrogen receptor (ER)-negative and progesterone receptor 
(PR)-negative tumor, defined as <1% positive stained cells utilizing an assay consistent 
with local standards. Documented HER2-negative tumor as per 2018 College of 
American Pathologists criteria 
4. Primary tumor ≥ 1.5 cm with any nodal status based on radiological or clinical 
assessment 
Note: bilateral tumors (i.e., synchronous cancers in both breasts) and/or multi-focal (ie, 
2 separate lesions in the same quadrant)/multi-centric (i.e., 2 separate lesions in different 
quadrants) tumors are allowed as long as TNBC is confirmed for at least one focus. 
Inflammatory breast cancer is also permitted.  
5. Provide archival tissue for the baseline tissue sample, consisting of representative 
formalin-fixed paraffin embedded (FFPE) tumor specimens in paraffin blocks (at least 
75-micron). Unstained slides are not permitted. If archival tissue is insufficient, fresh 
tissue biopsy is required.  
Note: Sponsor agreement is required for FFPE tumor tissues samples that were obtained 
greater than 30 days prior to the date that the informed consent was signed. 
6. ECOG performance status of 0 or 1 
7. Adequate organ function as demonstrated by the following laboratory values: 
a. Hemoglobin ≥ 9 g/dL without RBC transfusion within 2 weeks prior to first dose of 
study drug 
b. Absolute neutrophil count ≥ 1.5 × 109/L without G-CSF support within 2 weeks prior 
to first dose of study treatment 
c. Platelet count ≥ 100 × 109/L without transfusion within 2 weeks prior to first dose of 
study drug 
d. Estimated glomerular filtration rate ≥ 50 mL/minute/1.73 m2  
e. Total bilirubin ≤ 1.2 × the upper limit of normal (ULN)  
f. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 2.5 × ULN 

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8. Prothrombin time and/or international normalized ratio (INR) must be within normal 
limits of the local laboratory ranges 
9. Patient must agree to research tumor biopsies including at least one on-treatment biopsy 
(and additional biopsy at baseline, if required) 
10. Left ventricular ejection fraction of ≥50% or ≥ institution lower limit of normal as 
assessed by echocardiogram (ECHO) or multigated acquisition (MUGA) scan performed 
at screening 
11. Contraceptive use by women or male partners should be consistent with local regulations 
regarding the methods of contraception for those participating in clinical studies. Please 
see Section 17.3 for detailed instructions on methods of contraception requirements 
12. Capable of giving signed informed consent, which includes compliance with the 
requirements and restrictions listed in the informed consent form and in this protocol  
7.2. 
Exclusion Criteria  
A patient will not be eligible for participation in this study if any of the following criteria apply: 
1. Prior systemic therapies or radiation for current breast cancer 
2. History of invasive malignancy ≤3 years prior to signing informed consent except for 
adequately treated basal cell or squamous cell skin cancer or in situ cervical cancer 
3. History of breast cancer including ipsilateral ductal carcinoma in situ (DCIS) treated with 
radiotherapy at any time 
4. History of hypersensitivity to the active ingredient or any component of study drugs to be 
administered to patient (i.e., trilaciclib, doxorubicin, cyclophosphamide, paclitaxel, 
carboplatin) 
5. Previous exposure to doxorubicin of more than 200 mg/m2 (as lifetime exposure to 
doxorubicin is not to exceed 450 mg/m2) 
6. For patients who will receive pembrolizumab:  
a. History of active autoimmune disease that has required systemic treatment in past 
2 years (i.e., with use of disease modifying agents, corticosteroids, or 
immunosuppressive drugs). Replacement therapy (e.g., thyroxine, insulin, or 
physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency) 
is not considered a form of systemic treatment 
b. Diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other 
form of immunosuppressive therapy within 7 days prior to the first dose of study 
drugs 
c. History of (non-infectious) pneumonitis that required steroids or current pneumonitis 
d. Known history of active tuberculosis (Bacillus Tuberculosis) 
e. History of hypersensitivity to any anti-PD-1, anti-PD-L1, or anti-PD-L2 agent or with 
an agent directed to another co-inhibitory T cell receptor (e.g., CTLA-4, OX-40, 
CD137) 

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7. Receipt of a live, attenuated vaccine within 30 days prior to the first dose of study drugs 
or anticipation that such a live, attenuated vaccine will be required during the study 
treatment period. Other vaccine types such as inactivated or nucleic acid vaccines 
(e.g., those given for COVID-19 or influenza) are permitted if given > 21 days prior to 
first dose of study drug. In case of COVID-19 vaccinations requiring two doses, the 
second dose must be given >21 days prior to first dose of study drug 
8. History of severe hepatic impairment (defined as Child Pugh Class C or serum bilirubin 
level greater than 5 mg/dL) 
9. Uncontrolled ischemic heart disease or uncontrolled symptomatic congestive heart failure 
(Class II-IV as defined by the New York Heart Association [NYHA] functional 
classification system) 
10. Known history of stroke, cerebrovascular accident, severe/unstable angina, myocardial 
infarction, or coronary angioplasty/stenting/bypass grafting within 6 months prior to 
enrollment 
11. QTcF interval >480 msec at Screening. For patients with ventricular pacemakers, QTcF 
>500 msec 
12. Known serious active infection (e.g., human immunodeficiency virus [HIV], hepatitis B 
or C, tuberculosis). HIV testing is not required. Patients with past hepatitis B virus 
(HBV) infection or resolved HBV infection (defined as having a negative HBsAg test 
and a positive antibody to hepatitis B core antigen [anti-HBc] antibody test) are eligible. 
Patients positive for hepatitis C virus (HCV) antibody are eligible only if polymerase 
chain reaction is negative for HCV ribonucleic acid (RNA).  
13. Women who are pregnant or breastfeeding 
14. Participation in other studies involving active treatment with investigational drug(s) in 
Phases 1 to 4 within 30 days prior to the first dose of study drug 
15. Prior hematopoietic stem cell or bone marrow transplantation 
16. Other uncontrolled serious chronic disease or psychiatric condition that in the 
Investigator’s opinion could affect patient safety, compliance, or follow-up in the 
protocol 
17. Major surgical procedure, open biopsy, or significant traumatic injury within 30 days 
prior to first dose of study drug 

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8. 
SCHEDULE OF ASSESSMENTS 
The procedures and assessments to be performed during the study are outlined in Table 4. The 
timing and number of samples collected for biomarker testing may be altered based on emerging 
data without requiring an amendment if the blood volume per day or overall does not increase 
and the patient is not required to have additional clinic visits or prolongation of a clinic visit, 
i.e., the risk-benefit profile for the patient does not worsen.  
Unless otherwise specified, assessments are to be completed within ±1 day of the scheduled visit 
date. Unscheduled assessments and visits to manage patient safety may occur at the 
Investigator’s discretion.  
 

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Table 4:  
Schedule of Assessments 
Screening 
Trilaciclib 
Lead-In Phase 
Treatment Phase 
Definitive 
Surgery 
Safety 
Follow-up 
Visit 
End of 
Study 
Visit  
See Protocol 
Section for 
Additional 
Details 
 
 
 
Single 
dose  
mono. 
trila. 
On-tx 
biopsy  
 
Doxorubicin/ 
Cyclophosphamide 
+/- pembrolizumab 
Each cycle = 2 weeks 
Paclitaxel  
+/- carboplatin b 
+/- pembrolizumab b 
Each cycle = 1 week 
 
 
 
Protocol Activity 
C1 
D1a 
C2 
D1 
C3 
D1 
C4 
D1 
 
C5 through C16  
D1 
Visit Window 
Up to 21 days 
prior to first 
dose 
N/A 
7d ±1d 
after 
trila 
N/A 
±2d 
±2d 
±2d 
 
±1d 
 
3-5 weeks 
following 
tx. 
30d (+7) 
after last 
trila dose 
Within 
14d 
after 
surgery 
Informed consent 
X 
 
 
 
 
 
 
 
 
 
 
Section 13.3  
ER-/PR-/HER2- status 
X 
 
 
 
 
 
 
 
 
 
 
Section 11.1.1  
Inclusion/ exclusion 
criteria 
X 
 
 
 
 
 
 
 
 
 
 
Section 7  
Baseline characteristics 
and demographics 
X 
 
 
 
 
 
 
 
 
 
 
Section 11.1.2  
Medical and surgical 
history 
X 
 
 
 
 
 
 
 
 
 
 
Section 11.1.3  
Concomitant medications 
and procedures 
X 
X 
 
X 
X 
X 
X 
X (C5, 8, 11, 16 only) 
X 
X 
X 
Section 9.5  
Complete physical exam 
X 
 
 
 
 
 
 
 
 
 
 
Section 11.3.2 
Directed physical exam 
 
X 
 
X 
X 
X 
X 
X (C5, 8, 11, 16 only) 
 
 
 
Section 11.3.2 
Vitals 
X 
X 
 
X 
X 
X 
X 
X 
 
 
 
Section 11.3.1 
ECOG performance status 
X 
X 
 
X 
 
 
 
X (C5 and 16 only) 
 
 
X 
Section 11.3.3  
Adverse event reporting 
X 
X 
 
X 
X 
X 
X 
X 
X 
X 
X 
Section 11.3.7  
Hematology 
X 
X 
 
X 
X 
X 
X 
X 
 
 
 
Section 11.3.4  
Serum chemistry 
X 
X 
 
X 
X 
X 
X 
X 
 
 
 
Section 11.3.4 
Coagulation (PT or INR) 
X 
 
 
 
 
 
 
 
 
 
 
Section 11.3.4 
12-lead ECG 
X 
 
 
 
 
 
 
 
 
 
 
Section 11.3.5  
Echocardiogram or 
MUGA for LVEF 
assessment 
X 
 
 
 
 
 
 
 
 
 
 
Section 11.3.6  
Urinalysis 
X 
 
 
 
 
 
 
 
 
 
 
Section 11.3.4 
Urine/serum HCG 
(WOCBP only) 
X 
 
 
X 
 
 
 
X (C5, 11, 16 only) 
 
 
 
Section 11.3.4 

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Screening 
Trilaciclib 
Lead-In Phase 
Treatment Phase 
Definitive 
Surgery 
Safety 
Follow-up 
Visit 
End of 
Study 
Visit  
See Protocol 
Section for 
Additional 
Details 
 
 
 
Single 
dose  
mono. 
trila. 
On-tx 
biopsy  
 
Doxorubicin/ 
Cyclophosphamide 
+/- pembrolizumab 
Each cycle = 2 weeks 
Paclitaxel  
+/- carboplatin b 
+/- pembrolizumab b 
Each cycle = 1 week 
 
 
 
Protocol Activity 
C1 
D1a 
C2 
D1 
C3 
D1 
C4 
D1 
 
C5 through C16  
D1 
Visit Window 
Up to 21 days 
prior to first 
dose 
N/A 
7d ±1d 
after 
trila 
N/A 
±2d 
±2d 
±2d 
 
±1d 
 
3-5 weeks 
following 
tx. 
30d (+7) 
after last 
trila dose 
Within 
14d 
after 
surgery 
Biomarker and Efficacy Assessments 
Blood samples for 
biomarkers 
 
X (pre-
dose) 
X (pre-
biopsy) 
 
X 
(pre-
dose) 
 
 
 
X (-3 day) 
 
 
Section 11.2.2  
Tumor sample #1 
(Baseline) 
X 
 
 
 
 
 
 
 
 
 
 
Section 11.2.1  
Tumor sample #2 (On 
treatment) 
 
 
X 
 
 
 
 
 
 
 
 
Section 11.2.1 
Tumor sample #3 
(Surgery) 
 
 
 
 
 
 
 
 
X 
 
 
Section 11.2.1  
pCR assessment 
 
 
 
 
 
 
 
 
X 
 
 
 
Treatment 
Trilaciclib 
 
X 
 
X 
X 
X 
X 
X 
 
 
 
Section 9.1  
Doxorubicin/ 
cyclophosphamide 
 
 
 
X 
X 
X 
X 
 
 
 
 
Section 9.1  
Paclitaxel 
 
 
 
 
 
 
 
X 
 
 
 
Section 9.1 
Carboplatin AUC 1.5 
(Investigator discretion) 
 
 
 
 
 
 
 
X 
 
 
 
Section 9.1 
Pembrolizumab 
(Investigator discretion)  
 
 
 
X 
 
 
X 
 X (C9 and C15 only) 
 
 
 
 Section 9.1 
Definitive surgery 
 
 
 
 
 
 
 
 
X 
 
 
Section 11.3.8  
AUC=area under the curve; C=cycle; chemo=chemotherapy; d=day; ECG=electrocardiogram; ECOG=Eastern Cooperative Oncology Group; ER=estrogen receptor; HCG=human 
chorionic gonadotropin; HER2=human epidermal growth factor receptor 2; INR=international normalized ratio; LVEF=left ventricular ejection fraction; mono=monotherapy; 
MUGA=multiple-gated acquisition; N/A=not applicable; pCR=pathologic complete response; PR=progesterone receptor; PT=prothrombin time; q2w=every 2 weeks; 
trila=trilaciclib; tx=treatment; WOCBP=women of childbearing potential 
a C1D1 may be the same day as the on-treatment biopsy, as long as the biopsy is done prior to initiation of chemotherapy.  
b Per Investigator discretion.

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9. 
STUDY TREATMENT 
9.1. 
Study Drugs Administered 
Study drugs are defined as any investigational product, chemotherapy, immunotherapy, or 
growth factor support intended to be administered to a study patient according to the study 
protocol. Study drugs used in this protocol are described in Table 5. 

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Table 5:  
Study Drugs 
Name 
Trilaciclib  
Doxorubicin 
Cyclophosphamide 
Paclitaxel 
Carboplatin 
Pembrolizumab 
G-CSF 
(Filgrastim) 
G-CSF 
(Pegfilgastim) 
Type  
Investigational 
Product 
Chemotherapy 
Chemotherapy 
Chemotherapy 
Chemotherapy 
per Investigator 
discretion 
Immunotherapy 
per Investigator 
discretion 
Growth factor 
support 
Growth factor 
support 
Dose Formulation 
Single-use, sterile 
powder to be 
reconstituted and 
further diluted with 
250 mL of 5% 
dextrose in water 
(D5W) or 0.9% 
sodium chloride in 
water (normal saline) 
per the Pharmacy 
Manual 
 
See US prescribing information 
 
Unit Dose 
Strength(s) 
300 mg/20 mL  
Dosage Level(s) 
240 mg/m2 
administered as 
single-dose 
monotherapy in 
Trilaciclib Lead-In 
Phase, then on Day 1 
of each 
chemotherapy cycle 
60 mg/m2 every 
2 weeks for 
4 cycles 
(Cycles 1-4) 
600 mg/m2 every 
2 weeks for 4 cycles 
(Cycles 1-4) 
80 mg/m2 every 
week for 
12 cycles 
(Cycles 5-16) 
AUC 1.5 QW 
starting on Day 1 
of paclitaxel 
chemotherapy 
(Cycles 5-16) 
400 mg fixed dose 
Q6W starting on 
Day 1 of AC 
(Cycle 1) and 
continued through 
Treatment Phase 
5 μg/kg/day 
starting 
approximately 
24 hrs after each 
cycle of AC and 
continued for at 
least 72 hours 
100 μg/kg or 
6 mg 
administered 
approximately 
24 hrs after each 
cycle of AC  
Route of 
Administration 
IV 
IV bolus 
IV 
IV 
IV 
IV 
SC 
SC 
Infusion Time 
30 minutes 
N/A 
30 to 60 minutes or 
per institutional 
standard  
3 hours or per 
institutional 
standard  
15 to 60 minutes 
or per 
institutional 
standard 
30 minutes or per 
institutional 
standard 
N/A 
N/A 
AC=doxorubicin/cyclophosphamide; G-CSF=granulocyte colony stimulating factor; IV=intravenous; N/A=not applicable; Q6W=every 6 weeks; QW=every week; 
SC=subcutaneous; US=United States

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9.1.1. 
Dose, Dosing Regimen, and Route 
9.1.1.1. 
Trilaciclib 
Trilaciclib for injection, 300 mg/vial is supplied as a sterile, preservative-free, yellow, 
lyophilized cake in a single-dose vial (300 mg/20 mL). Trilaciclib 240 mg/m2 will be 
administered as an IV infusion as monotherapy during the Trilaciclib Lead-In Phase and just 
prior to chemotherapy during the Treatment Phase. 
Trilaciclib must be reconstituted and further diluted prior to IV infusion as outlined in the 
Pharmacy Manual. Aseptic technique must be used for reconstitution and dilution. Following 
reconstitution, the solution must then be diluted to the calculated dose based on the body surface 
area (BSA) of the patient. Actual body weight should be utilized for dose calculations. If there is 
a change in body weight ≥10% relative to the weight at the time of the last dose calculation, dose 
should be recalculated. Recalculation of dose more frequently per local institutional guidelines is 
permitted. Dose recalculation to adjust for changes in body weight will not be considered a dose 
reduction and will be made at the discretion of the Investigator. No trilaciclib dose reductions for 
toxicity management will be allowed during the study. 
9.1.1.1.1. Administration of Trilaciclib 
• Administer diluted trilaciclib solution as a 30-minute IV infusion completed within 
4 hours prior to the start of chemotherapy.  
• When administered with chemotherapy, trilaciclib is always administered first. 
Results from hematology labs should be reviewed prior to administration of 
trilaciclib. If administration of chemotherapy is delayed or discontinued, trilaciclib 
will also be delayed or discontinued. 
• Diluted trilaciclib solution must be administered with an infusion set, including an 
in-line filter (0.2 or 0.22 micron). Compatible in-line filters include polyether sulfone, 
polyvinylidene fluoride, and cellulose acetate.  
• Do not administer diluted trilaciclib solution with a polytetrafluorethylene (PTFE) 
in-line filter. PTFE in-line filters are not compatible with diluted trilaciclib solution. 
• Do not co-administer other drugs through the same infusion line.  
• Do not co-administer other drugs through a central access device unless the device 
supports co-administration of incompatible drugs.  
If there is any study drug remaining in the infusion bag at the end of the 30 minutes, the infusion 
should be continued at the same rate until the entire contents of the bag have been administered 
to ensure patients receive the full dose. Upon completion of infusion of diluted trilaciclib 
solution, the infusion line/cannula must be flushed with at least 20 mL sterile 5% dextrose in 
water or sterile 0.9% sodium chloride in water (normal saline). 
The infusion rate may be decreased to manage an infusion-related AE; for example, if a patient 
experiences a burning sensation during infusion, the duration of infusion may be increased to 
45 minutes (or longer if clinically indicated) to alleviate the symptom. 

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9.1.1.2. 
Chemotherapy Backbone: Doxorubicin, Cyclophosphamide, and Paclitaxel  
Descriptions of the formulations of commercially available doxorubicin, cyclophosphamide, and 
paclitaxel can be found in the respective current prescribing information. The dose amount 
required for chemotherapy will be calculated based on milligrams per square meter of BSA 
(mg/m2). Premedications should be administered as per prescribing information or per 
institutional standard. 
Doxorubicin at a dose level of 60 mg/m2 will be administered by IV on Day 1 of Cycles 1 
through 4 as instructed per prescribing information or per institutional standard.  
Cyclophosphamide at a dose level of 600 mg/m2 will be administered by IV as instructed per 
prescribing information or per institutional standard on Day 1 of Cycles 1 through 4.  
Paclitaxel at a dose level of 80 mg/m2 will be administered by IV per prescribing information or 
per institutional standard on Day 1 of Cycles 5 through 16.  
Actual body weight should be utilized for dose calculations. If there is a change in body weight 
≥10% relative to the weight at the time of the last dose calculation, dose should be recalculated. 
Recalculation of dose more frequently per local institutional guidelines is permitted. Dose 
recalculation to adjust for changes in body weight will not be considered a dose reduction and 
will be made at the discretion of the Investigator. 
9.1.1.3. 
Treatment per Investigator Discretion: Carboplatin and Pembrolizumab  
Descriptions of the formulations of commercially available carboplatin and pembrolizumab can 
be found in the respective current prescribing information. If carboplatin is administered, the 
dose amount required will be calculated as AUC at a dose level of 1.5 weekly during paclitaxel 
treatment. If pembrolizumab is administered, the dose level will be 400 mg every 6 weeks 
starting with Cycle 1 of AC and continued while receiving chemotherapy. Premedications should 
be administered as per prescribing information or per institutional standard.  
9.1.1.3.1. Sequence of Administration of Study Drugs 
The sequence of administration on treatment days as outlined in Table 4 is as follows (Figure 4): 
• Trilaciclib is always administered first and infusion must be complete before 
administrating other agents. 
• If pembrolizumab is given, it will be administered after trilaciclib and before 
chemotherapy. Pembrolizumab may be administered immediately following 
trilaciclib, but not until the completion of the trilaciclib infusion. 
• SOC chemotherapy (doxorubicin/cyclophosphamide or paclitaxel) is always 
administered after trilaciclib (and pembrolizumab if given). Trilaciclib (and 
pembrolizumab) infusions must be complete before initiating chemotherapy. The 
interval between completion of the trilaciclib infusion and the initiation of the first 
chemotherapy drug should not be greater than 4 hours.  
• The order of administration of doxorubicin and cyclophosphamide is per institutional 
standard. 

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• If carboplatin is given, the order of administration of paclitaxel and carboplatin is per 
institutional standard.  
Figure 4: 
Sequence of Administration of IV Study Drugs 
 
9.1.2. 
Preparation, Handling, Storage, and Accountability 
The Investigator or institution is responsible for study drug accountability, reconciliation, and 
record maintenance (i.e., receipt, reconciliation, dispensing, and final disposition records). The 
Investigator/institution may assign some or all of the Investigator’s/institution’s duties for 
investigational product(s) accountability to an appropriate pharmacist or another appropriate 
individual who is under the supervision of the Investigator/institution. 
Further guidance and information are provided in the Pharmacy Manual. 
9.1.3. 
Treatment Compliance 
The Investigator or designee will dispense the study drug, via a Pharmacist/designee, only for 
use by patients enrolled in the study as described in this protocol (Section 9.1). The study drug 
shall not be used for reasons other than those described in this protocol. The clinical study site 
will maintain records of study drug receipt, preparation, and dispensing, including the applicable 
lot and vial numbers; patient’s height, body weight, and BSA; date and time of the start of each 
infusion for trilaciclib, doxorubicin, cyclophosphamide, paclitaxel (and carboplatin and 
pembrolizumab if appliable); and planned and actual infusion volumes. 
9.2. 
Criteria for Starting Study Treatment and Each Subsequent Cycle 
Patients must meet specific hematologic criteria for each dosing day per Table 6 and Table 7 and 
any nonhematologic toxicities (except alopecia) must be ≤ Grade 2 or have returned to baseline. 
Study drug administration will continue as per protocol to completion or early discontinuation of 
chemotherapy, until unacceptable toxicity, Investigator’s decision to withdraw the patient from 
study treatment, pregnancy of the patient, noncompliance with study treatment or procedure 
requirements, consent withdrawal, becoming lost-to-follow-up, death, or administrative reasons 
require cessation of treatment. 
Note: C1D1 of the Treatment Phase may be the same day as the on-treatment biopsy (7 days 
[±1 day] after trilaciclib monotherapy), as long as the biopsy is done prior to initiation of 
chemotherapy. 
9.3. 
 Toxicity Management and Dose Modifications 
Toxicities will be graded according to the National Cancer Institute (NCI)-Common 
Terminology Criteria for Adverse Events (CTCAE), Version 5.0. For dose delays due to toxicity, 
the patient should be followed (at least) weekly to monitor the toxicity until treatment criteria are 
met or until they discontinue treatment. No more than 2 dose reductions in total are allowed per 

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study drug (expect trilaciclib for which no dose reductions are allowed). Toxicity that requires 
dose reductions more than twice for one study drug will lead to discontinuation of that study 
drug. If a dose delay does not require discontinuation of chemotherapy, patients may resume 
treatment when dosing criteria are met and continue on treatment to complete the full number of 
cycles per protocol. 
All dose reductions are permanent, and no dose increases will occur following a dose reduction. 
Likewise, discontinuation from treatment is permanent and once a patient has had a component 
or entire treatment discontinued, it may not be restarted. 
9.3.1. 
Dose Modifications for Trilaciclib 
Trilaciclib dosing is not to be modified and will remain at 240 mg/m2 throughout the study. 
Trilaciclib will be administered only on days that chemotherapy is administered except in the 
Trilaciclib Lead-In Phase when monotherapy trilaciclib will be given. Recommendations for 
management of trilaciclib AESIs are provided in Table 9. 
9.3.2. 
Dose Modifications for Chemotherapy 
Doxorubicin, cyclophosphamide, paclitaxel, and carboplatin dose reductions for hematologic 
toxicities are based on values obtained within 24 hours of chemotherapy on Day 1 of a cycle and 
at any time for non-hematologic toxicities. Dose modifications are permitted for chemotherapy 
according to the organ system showing the greatest degree of drug-related toxicity and are to be 
managed per Investigator discretion and institutional guidelines; recommendations are provided 
in Table 6 and Table 7.  
Table 6: 
Dose Modification Recommendations for Doxorubicin and 
Cyclophosphamide (AC) 
Toxicities 
Grade or Actual 
Value 
Action 
Hematologic 
 
 
Neutropenia 
≥1000/mm3  
Grade 1/Grade 2  
No change to AC 
 
<1000/mm3  
Grade 3/Grade 4 
Hold AC until ANC ≥1000/mm3. 
Resume based on timing of recovery: 
 
≤1week: No change to AC 
 
≥1 but <3 weeks: Reduce AC by 20% for all 
subsequent cycles 
 
≥3 weeks: Permanently discontinue AC (see 
Section 9.3.4 below) 
Febrile neutropenia 
ANC ≤1000/mm3, 
fever ≥38.5°C 
Grade 3 and Grade 4 
Hold AC until resolved (ANC >1000/mm3, fever 
<38.5°C, and resolution of any signs of infection) 
Resume according to number of episodes: 
 
First episode: no change to AC 
 
Second episode: Reduce AC by 20% for all 
subsequent cycles 
 
Third episode: Permanently discontinue AC (see 
Section 9.3.4 below) 

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Toxicities 
Grade or Actual 
Value 
Action 
Thrombocytopenia 
75-<100,000/mm3 
Grade l 
Hold AC until ≥100,000/mm3, resume AC based on timing 
of recovery: 
 
≤1week: No change to AC 
 
≥1 but <3 weeks: Reduce AC by 20% for all 
subsequent cycles. 
 
≥3 weeks: Permanently discontinue AC (see 
Section 9.3.4 below) 
 
<75,000/mm3 
≥ Grade 2 
Hold AC until ≥100,000/mm3  
 
Reduce AC by 20% for all subsequent cycles 
 
Permanently discontinue AC if held for ≥3 weeks in 
a row (see Section 9.3.4 below)  
Anemia 
All grades 
No change to AC 
 
Iron studies should be done and iron should be 
replaced as indicated. 
 
Red blood cell transfusions can be given at the 
Investigator' s discretion. 
Non-Hematologic 
 
 
Nausea/Vomiting 
Grade l or 2 
No change to AC 
 
≥Grade 3 
Hold AC until resolved to ≤Grade 1. 
 
Resume AC at same dose with modification of 
premedication 
 
Second episode ≥Grade 3 despite maximum 
supportive care, reduce AC by 20% for all 
subsequent cycles 
Mucositis/Stomatitis 
Grade l or 2 
No change to AC 
 
≥Grade 3 
Hold until resolved to ≤Grade 1. 
 
Resume AC at same dose with modification of 
premedication 
 
Second episode ≥Grade 3 despite maximum 
supportive care, reduce AC by 20% for all 
subsequent cycles 
Hepatic (e.g., AST, 
ALT, and/or bilirubin) 
Grade 1 
No change to AC 
 
≥ Grade 2 or 3 
• 
Hold AC until resolved to Grade 1 and resume 
same dose 
• 
Permanently discontinue AC if held for ≥ 3 
weeks in a row (see Section 9.3.4 below) 
 
Grade 4 
• 
Discontinue AC (see Section 9.3.4 below) 
Note all concurrent ALT/AST >3xULN and total 
bilirubin >2xULN should be evaluated for potential 
Hy’s law (see Section 9.3.6) 
Cardiac toxicity 
Grade 1 or 2 
No change to AC 
 
≥ Grade 3 
Permanently discontinue doxorubicin (see Section 9.3.4 
below) 

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Toxicities 
Grade or Actual 
Value 
Action 
Anaphylaxis/ 
hypersensitivity 
Mild 
Complete infusion, observe until symptom resolved 
 
Moderate 
• 
Stop infusion and treat per standard practice 
• 
Resume infusion at half of the infusion speed if 
symptoms resolve 
• 
Stop if symptoms recur 
 
Severe 
Stop infusion immediately and permanently discontinue 
treatment (see Section 9.3.4 below) 
Other significant 
toxicities excluding 
fatigue, alopecia and 
leukopenia per 
Investigator discretion 
Grade 2 
• 
Hold AC until resolve to ≤ Grade 1 
• 
Resume at same dose and increase supportive care 
measures, if available 
≥ Grade 3 
• 
Hold AC and discuss with Medical Monitor for 
further instructions 
• 
If ≥ Grade 3 toxicity recurs upon rechallenge, 
Permanently discontinue (see Section 9.3.4 below) 
AC=doxorubicin/cyclophosphamide; ANC=absolute neutrophil count; ALT=alanine aminotransferase; 
AST=aspartate aminotransferase; ULN=upper limit of normal 
Table 7: 
Dose Modification Recommendations for Paclitaxel Alone or With 
Carboplatin 
Toxicities 
Grade or Actual 
Value 
Action 
Hematologic 
 
 
Neutropenia 
≥1000/mm3  
Grade 1/Grade 2 
No change to paclitaxel or carboplatin 
• 
For ANC ≤1500/mm3, prophylactic G-CSF (filgrastim) 
use at the discretion of the Investigator a 
 
<1000/mm3 
Grade 3/Grade 4 
Hold paclitaxel and/or carboplatin until ANC 
≥1000/mm3. 
G-CSF per Investigator discretion a. 
Resume paclitaxel and/or carboplatin based on timing 
of recovery: 
• 
≤1 week: No change to paclitaxel and carboplatin 
• 
>1 but <3 weeks: Reduce paclitaxel dose by 
70 mg/m2and/or carboplatin to AUC 1.1 for all 
subsequent cycles 
, 
• 
≥3 weeks: Permanently discontinue paclitaxel and/or 
carboplatin (see Section 9.3.4 below) 

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Toxicities 
Grade or Actual 
Value 
Action 
Febrile neutropenia 
ANC ≤1000/mm3 
and fever ≥38.5°C 
Grade 3/Grade 4 
Hold paclitaxel and/or carboplatin until resolved (ANC 
>1000/mm3, fever <38.5°C, and resolution of any signs of 
infection). G-CSF (filgrastim) use at the discretion of the 
Investigator a  
Resume paclitaxel and/or carboplatin according to number of 
episodes: 
• 
First episode: no change to paclitaxel or carboplatin. 
Recommend adding prophylactic G-CSF for 
subsequent cycles 
• 
Second episode: Reduce paclitaxel dose to 70 mg/m2 
and/or carboplatin to AUC 1.1 for all subsequent 
cycles 
• 
Third episode: Permanently discontinue paclitaxel 
and/or carboplatin (see Section 9.3.4 below) 
Thrombocytopenia 
75-<100,000/mm3 
Grade 1 
Hold paclitaxel and/or carboplatin until ≥100,000/mm3, 
resume treatment based on timing of recovery: 
• 
≤1 week - no change to paclitaxel or carboplatin 
• 
>1 but <3 weeks - Reduce paclitaxel dose to 
70 mg/m2 and/ or carboplatin to AUC 1.1) for all 
subsequent doses 
• 
≥3 weeks: Permanently discontinue paclitaxel and/or 
carboplatin (see Section 9.3.4 below) 
 
<75,000/mm3 
≥Grade 2 
Hold paclitaxel and/or carboplatin until ≥100,000/mm3. 
• 
Reduce paclitaxel dose to 70 mg/m2 and/or 
carboplatin to AUC 1.1 for all subsequent doses. 
• 
Permanently discontinue paclitaxel and/or carboplatin 
if held for ≥ 3 weeks in a row (see Section 9.3.4 
below) 
Anemia 
All grades 
No change to paclitaxel or carboplatin 
• 
Iron studies should be done and iron should be 
replaced as indicated 
• 
Red blood cell transfusions can be given at the 
Investigator discretion 
Non-Hematologic 
 
 
Nausea/Vomiting 
Grade 1 or 2 
No change to paclitaxel or carboplatin 
 
≥ Grade 3 
Hold paclitaxel and/or carboplatin until ≤ Grade 1. 
• 
Resume paclitaxel and/or carboplatin at same dose 
with modification of premedication 
• 
Second episode ≥ Grade 3 despite with maximum 
supportive care, reduce paclitaxel to 70 mg/m2 and/or 
carboplatin to AUC 1.1 for all subsequent doses 
Mucositis/Stomatitis 
Grade 1 or 2 
No change to paclitaxel or carboplatin 
 
≥ Grade 3 
Hold paclitaxel until ≤Grade 1. 
• 
Resume paclitaxel at same dose with modification of 
premedication 
• 
Second episode ≥ Grade 3 despite maximum 
supportive care, reduce paclitaxel to 70 mg/m2, 
and/or carboplatin to AUC 1.1 for all subsequent 
doses 

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Toxicities 
Grade or Actual 
Value 
Action 
Neurotoxicity 
Grade 1 or 2 
No change to paclitaxel or carboplatin 
 
Grade 3 
Hold paclitaxel and/or carboplatin until ≤Grade 2. 
• 
Reduce paclitaxel dose to 70 mg/m2, and/ or 
carboplatin to AUC 1.1 for all subsequent doses 
• 
Permanently discontinue paclitaxel and/or carboplatin 
if held for ≥ 3 weeks in a row (see Section 9.3.4 
below) 
 
Grade 4 
• 
Permanently discontinue paclitaxel and/or carboplatin 
if held for ≥ 3 weeks in a row (see Section 9.3.4 
below) 
Hepatic (e.g., AST, 
ALT, and/or bilirubin) 
Grade 1 
No change to paclitaxel or carboplatin 
 
Grade 2 or 3 
• 
Bilirubin fractionation should be performed if total 
bilirubin > 1.5xULN; if mostly indirect, continue 
dose and evaluate for alternate causes such as 
Gilbert’s syndrome  
• 
Hold paclitaxel and/or carboplatin until ≤ Grade 1 
and resume at same dose level 
• 
Permanently discontinue paclitaxel and/or carboplatin 
if held for ≥ 3 weeks in a row (see Section 9.3.4 
below) 
 
Grade 4 
• 
Permanently discontinue paclitaxel and/or carboplatin 
(see Section 9.3.4 below) 
Note all concurrent ALT/AST >3xULN and total 
bilirubin > 2xULN should be evaluated for 
potential Hy’s law (see Section 9.3.6) 
Anaphylaxis 
/hypersensitivity 
Mild 
• 
Complete paclitaxel or carboplatin infusion, observe 
until symptoms resolve 
 
Moderate 
• 
Stop infusion and treat per standard practice 
• 
Resume infusion at half of the infusion speed if 
symptoms resolve  
• 
Stop if symptoms recur 
 
Severe 
• 
Stop infusion immediately and permanently 
discontinue paclitaxel and/or carboplatin (see 
Section 9.3.4 below) 
Other significant 
toxicities excluding 
fatigue, alopecia, and 
leukopenia per 
Investigator discretion 
Grade 2 
• 
Hold paclitaxel and/or carboplatin until ≤ Grade 1 
• 
Resume at the same dose level and increase 
supportive care measures, if available 
≥ Grade 3 
• 
Hold paclitaxel and/or carboplatin, and discuss with 
Medical Monitor for further instructions 
• 
If ≥ Grade 3 toxicity recurs upon rechallenge, 
permanently discontinue paclitaxel and/or carboplatin 
(see Section 9.3.4 below) 
ALT=alanine aminotransferase; ANC=absolute neutrophil count; AST=aspartate aminotransferase; AUC=area 
under the curve; G-CSF=granulocyte colony stimulating factor; ULN=upper limit of normal 
a Filgrastim should not be given on the same day as chemotherapy. Pegfilgrastim may not be used with paclitaxel 
due to its weekly dosing schedule. 

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9.3.3. 
Dose Modifications for Pembrolizumab  
Pembrolizumab dosing is not to be modified and will remain at 400 mg fixed dose throughout 
the study. Adverse events (both non-serious and serious) associated with pembrolizumab 
exposure may represent an immunologic etiology. These AEs may occur shortly after the first 
dose or several months after the last dose of treatment. Recommendations for withholding or 
discontinuing pembrolizumab are provided in Table 8 below. Importantly, permanently 
discontinue for any severe or Grade 3 (Grade 2 for recurrent pneumonitis) drug-related AE that 
recurs or any life-threatening event. 
Table 8: 
Dose Modification Recommendations for Pembrolizumab  
Toxicity 
Hold Treatment 
For Grade 
Timing for Restarting 
Treatment 
Treatment Discontinuation 
Diarrhea/Colitis 
Grade 2 or 3 
Toxicity resolves to Grade 0-1 
Toxicity does not resolve within 
6 weeks of last dose or inability to 
reduce corticosteroid to 10 mg or 
less of prednisone or equivalent per 
day within 6 weeks 
Grade 4 
Permanently discontinue 
pembrolizumab 
Permanently discontinue 
pembrolizumab 
AST, ALT, or 
Increased Bilirubin 
Grade 2 
Toxicity resolves to Grade 0-1 
Toxicity does not resolve within 
6 weeks of last dose 
Grade 3 or 4 
Permanently discontinue 
pembrolizumab 
Permanently discontinue 
pembrolizumab 
Type 1 diabetes 
mellitus (T1DM) if 
new onset including 
diabetic ketoacidosis 
or Hyperglycemia (≥ 
Grade 3) if associated 
with ketosis 
(ketonuria) or 
metabolic acidosis 
 
See toxicity 
Hold pembrolizumab for new 
onset Type 1 diabetes mellitus 
or Grade 3-4 hyperglycemia 
associated with evidence of 
beta cell failure. 
Resume pembrolizumab when 
patient is clinically and 
metabolically stable 
Hypophysitis 
Grade 2 to 4 
Toxicity resolves to Grade 0-
1. Therapy with 
pembrolizumab can be 
continued while endocrine 
replacement therapy is 
instituted 
Toxicity does not resolve within 
6 weeks of last dose or inability to 
reduce corticosteroid to 10 mg or 
less of prednisone or equivalent per 
day within 6 weeks 
Hyperthyroidism 
Grade 3 
Toxicity resolves to Grade 0-1 
Toxicity does not resolve within 
6 weeks of last dose or inability to 
reduce corticosteroid to 10 mg or 
less of prednisone or equivalent 
per day within 6 weeks 
Grade 4 
Permanently discontinue 
pembrolizumab 
Permanently discontinue 
pembrolizumab 

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Toxicity 
Hold Treatment 
For Grade 
Timing for Restarting 
Treatment 
Treatment Discontinuation 
Hypothyroidism 
N/A 
Therapy with pembrolizumab 
can be continued while 
thyroid 
replacement therapy is 
instituted 
Therapy with pembrolizumab can 
be continued while thyroid 
replacement therapy is instituted 
Infusion Reaction 
Grade 3 or 4 
Permanently discontinue 
pembrolizumab 
Permanently discontinue 
pembrolizumab 
Pneumonitis 
Grade 2 
Toxicity resolves to Grade 0-1 
Toxicity does not resolve within 
6 weeks of last dose or inability to 
reduce corticosteroid to 10 mg or 
less of prednisone or equivalent 
per day within 6 weeks 
Grade 3-4 or 
recurrent 
Grade 2 
Permanently discontinue 
pembrolizumab 
Permanently discontinue 
pembrolizumab 
Renal Failure or 
Nephritis 
 
Grade 2 
Toxicity resolves to 
Grade 0-1 
Toxicity does not resolve within 
6 weeks of last dose or inability to 
reduce corticosteroid to 10 mg or 
less of prednisone or equivalent per 
day within 6 weeks 
Grade 3-4 
Permanently discontinue 
pembrolizumab 
Permanently discontinue 
pembrolizumab 
All Other Drug- 
Related Toxicitya 
Grade 3 or 
Severe 
Toxicity resolves to 
Grade 0-1 
Toxicity does not resolve within 6 
weeks of last dose or inability to 
reduce corticosteroid to 10 mg or 
less of prednisone or equivalent per 
day within 6 weeks 
Grade 4 
Permanently discontinue 
pembrolizumab 
Permanently discontinue 
pembrolizumab 
AE=adverse event; ALT=alanine aminotransferase; AST=aspartate aminotransferase 
a Patients with intolerable or persistent Grade 2 drug-related AEs may hold study drug per Investigator discretion. 
Permanently discontinue study drug for persistent Grade 2 adverse reactions for which treatment with study drug 
has been held, that do not recover to Grade 0-1 within 6 weeks of the last dose. 
9.3.4. 
Discontinuation of a Component or Entire Regimen 
During the study, if one or more than one component of the regimen must be discontinued due to 
toxicity, the Investigator should follow these recommendations: 
• If all chemotherapy drugs are discontinued, then discontinue trilaciclib and proceed 
with surgery.  
• If only trilaciclib is discontinued, then continue chemotherapy ± pembrolizumab for 
the remaining cycles as planned per protocol, followed by surgery.  

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• If doxorubicin and/or cyclophosphamide are discontinued, then proceed with 
trilaciclib and paclitaxel ± carboplatin ± pembrolizumab as planned per protocol, 
followed by surgery. 
• If only paclitaxel is discontinued, then continue with trilaciclib ± carboplatin ± 
pembrolizumab, if applicable OR if only receiving paclitaxel with trilaciclib, then 
proceed to surgery as per protocol.   
• If only carboplatin is discontinued, then continue with paclitaxel, trilaciclib, 
± pembrolizumab for the remaining cycles as planned per protocol, then proceed to 
surgery. 
• If only pembrolizumab is discontinued, then continue with trilaciclib and 
chemotherapy as planned per protocol, then proceed to surgery. 
Please note that with the exception of the trilaciclib monotherapy Lead In Phase, trilaciclib 
monotherapy is prohibited. 
9.3.5. 
Recommended Actions with Trilaciclib for Adverse Events of Special Interest  
Suggested actions to be taken with trilaciclib following AESI are provided in Table 9. 
Table 9:  
Recommended Actions with Trilaciclib Following AESIs 
AESI 
Severity 
Recommended Action 
Injection site 
reactions including 
phlebitis and 
thrombophlebitis 
Grade 1: Tenderness with or without 
symptoms (e.g., warmth, erythema, 
itching) 
Interrupt or slow infusion of trilaciclib. If 
0.9% normal saline is being used as a 
diluent/flush, consider changing to 5% 
dextrose as appropriate for subsequent 
infusions. 
Grade 2: Pain; lipodystrophy; 
edema; phlebitis 
Interrupt infusion of trilaciclib. If pain not 
severe, follow instructions for Grade 1. 
Otherwise, stop infusion in extremity and 
rotate site of infusion to site in alternative 
extremity. If 0.9% normal saline is being 
used as a diluent/flush, consider changing to 
5% dextrose as appropriate for subsequent 
infusions. Central access may also be 
considered. 
Grade 3: Ulceration or necrosis; 
severe tissue damage; operative 
intervention indicated.  
Grade 4: Life threatening 
consequences; urgent interventions 
indicated. 
Stop infusion and permanently discontinue 
trilaciclib. 

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AESI 
Severity 
Recommended Action 
Acute drug 
hypersensitivity 
reactions  
Grade 2: Moderate; minimal, local 
or noninvasive intervention 
indicated; limiting age-appropriate 
instrumental Activities of Daily 
Living (ADL) 
Stop infusion and hold trilaciclib until 
recovery to Grade ≤1 or baseline, then 
consider resuming trilaciclib. If Grade 2 
recurs, permanently discontinue trilaciclib. 
Grade 3: Severe or medically 
significant but not immediately life-
threatening; hospitalization or 
prolongation of hospitalization 
indicated; disabling; limiting self-
care ADL. 
OR  
Grade 4: Life-threatening 
consequences; urgent intervention 
indicated. 
Permanently discontinue trilaciclib. 
ILD/pneumonitis 
Grade 2 (symptomatic) 
Hold trilaciclib until recovery to Grade ≤1 or 
baseline, then consider resuming trilaciclib. 
If Grade 2 recurs, permanently discontinue 
trilaciclib. 
Grade 3: Severe symptoms; limiting 
self-care ADL; oxygen indicated.  
OR  
Grade 4: Life-threatening respiratory 
compromise; urgent intervention 
indicated (e.g., tracheotomy or 
intubation) 
Permanently discontinue trilaciclib. 
Other toxicities 
Grade 3: Severe or medically 
significant but not immediately life-
threatening; hospitalization or 
prolongation of hospitalization 
indicated; disabling; limiting self-
care ADL. 
Hold trilaciclib until recovery to Grade ≤1 or 
baseline, then consider resuming trilaciclib. 
If Grade 3 recurs, permanently discontinue 
trilaciclib. 
Grade 4: Life-threatening 
consequences; urgent intervention 
indicated. 
Permanently discontinue trilaciclib. 
AESI=adverse event of special interest; ADL=activities of daily living; ILD=interstitial lung disease 

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9.3.6. 
Hy’s Law Management 
Abnormal values in AST and/or ALT concurrent with abnormal elevations in total bilirubin that 
meet the criteria outlined below in the absence of other causes of liver injury are considered 
potential cases of drug-induced liver injury (potential Hy’s Law cases) and should always be 
considered important medical events.  
Patients who present with the following laboratory abnormalities should be evaluated further to 
determine the etiology of the abnormal laboratory values: 
• Baseline AST or ALT and total bilirubin values are within the normal range and the 
patient subsequently presents with AST or ALT ≥3 × ULN concurrent with a total 
bilirubin ≥2 × ULN with no evidence of hemolysis and an alkaline phosphatase 
≤2 × ULN or not available.  
• Pre-existing baseline ALT, AST, OR total bilirubin values are above the ULN, and 
the patient subsequently presents with: 
− AST or ALT ≥2 × baseline value AND ≥3 × ULN, or ≥8 × ULN (whichever is 
smaller)  
− concurrent with total bilirubin ≥2 × baseline value OR ≥3 × ULN (whichever is 
smaller). 
The patient should return to the investigational site and be evaluated as soon as possible, 
preferably within 48 hours from awareness of the abnormal results. This evaluation should 
include laboratory tests, detailed history, and physical assessment. In addition to repeating AST 
and ALT, laboratory tests should include albumin, creatine kinase, total bilirubin, direct and 
indirect bilirubin, gamma-glutamyl transferase, prothrombin time, and alkaline phosphatase. A 
detailed history, including relevant information, such as review of ethanol, acetaminophen, 
recreational drug and supplement consumption, family history, occupational exposure, sexual 
history, travel history, history of contact with a jaundiced patient, surgery, blood transfusion, 
history of liver or allergic disease, and work exposure, should be collected. Further testing for 
acute hepatitis A, B, or C infection and liver imaging (e.g., biliary tract) may be warranted. All 
cases confirmed on repeat testing as meeting the laboratory criteria defined above, with no other 
cause for LFT abnormalities identified at the time should be considered potential Hy’s Law cases 
irrespective of availability of all the results of the investigations performed to determine etiology 
of the abnormal LFTs. Such potential Hy’s Law cases should be reported as serious adverse 
events (SAEs). 
9.3.7. 
Management of Nausea and Vomiting 
Necessary supportive care (e.g., antiemetics, antidiarrheals) administered per standard of care at 
the study center will be permitted.  
9.4. 
Supportive Care Interventions 
9.4.1. 
Granulocyte-Colony Stimulating Factor Usage 
Granulocyte-colony stimulating factor (G-CSF) should be administered after each cycle of AC 
chemotherapy or per Investigator discretion. G-CSF 5 μg/kg/day administered subcutaneously 

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(SC) should be initiated at 24 hours post-dose and continued for at least 72 hours. Pegfilgrastim 
administered SC as either a single dose of 100 μg/kg (individualized) or a single dose of 6 mg 
(general approach) at 24 hours after chemotherapy is also acceptable. 
Prophylactic G-CSF use during treatment with paclitaxel (with or without carboplatin) is allowed 
per growth factor/neutropenia management guidelines (e.g., American Society of Clinical 
Oncology [ASCO]), package inserts, and Investigator discretion (Aapro, 2011; Smith, 2015). If 
in any cycle a patient experiences febrile neutropenia and/or is at high risk for 
infection-associated complications, G-CSF/granulocyte-macrophage colony-stimulating factor 
(GM-CSF) should be used to treat the febrile neutropenia event per ASCO guidelines and 
package inserts.  
9.4.2. 
Transfusions 
Red Blood Cells 
Based on the NCCN Clinical Practice Guidelines in Oncology for Hematopoietic Growth Factors 
Version 2.2020 and the AABB Clinical Practice Guidelines, the following RBC transfusion 
thresholds are recommended (Carson, 2016; Goel, 2018); however, the patient’s clinical situation 
should always be the primary guiding factor when deciding to transfuse. 
• Transfusion is not indicated until the hemoglobin level is ≤7 g/dL for hospitalized 
adult patients who are hemodynamically stable. 
• An RBC transfusion threshold of ≤8 g/dL is recommended for patients undergoing 
orthopedic surgery, cardiac surgery, and those with preexisting cardiovascular 
disease.  
• Patients with symptomatic anemia should be transfused per Investigator discretion 
regardless of hemoglobin levels. 
Platelets 
Platelet transfusion is recommended at a threshold of ≤10 x 109/L. Platelets should also be 
transfused in any patient who is bleeding with a platelet count <50 x 109/L (100 x 109/L for 
central nervous system or ocular bleeding) (Kaufman, 2015; Schiffer, 2001). 
9.5. 
Prior/Concomitant Medications, Procedures, and Vaccinations  
Medications and Procedures: 
All prior medications and procedures will be collected from 21 days prior to signing the ICF. All 
concomitant medications including prescription medications, over-the-counter preparations, 
growth factors, and blood products from informed consent through the End of Study Visit will be 
documented, where possible. The use of gonadotrophin-releasing hormone (GnRH) agonist 
therapy (e.g., goserelin acetate [Zolodex®]) for ovarian preservation and bisphosphonates or 
rank ligand inhibitors to prevent osteopenia or osteoporosis is allowed during chemotherapy. 
Administration of other concomitant non-protocol anticancer therapies is not permitted while on 
this study. This includes any low-dose systemic chemotherapeutic agent given for a 
non-oncologic purpose (e.g., low-dose methotrexate for rheumatoid arthritis). Administration of 
other concomitant investigational agents for any indication is not permitted while on this study. 

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Any medication that is contraindicated when using doxorubicin, cyclophosphamide, paclitaxel, 
carboplatin or pembrolizumab (when applicable) is not permitted, and warnings and precautions 
for use of these study drugs should be observed.  
Avoid concomitant use with certain OCT2, MATE1, and MATE-2K substrates where minimal 
concentration changes may lead to serious or life-threatening toxicities (Section 4.4.1.2). 
Any diagnostic, therapeutic, or surgical procedure performed during the study period will be 
documented. Documentation will include information regarding the date(s), indication(s), 
description of the procedure(s), and any clinical or pathological findings, if available.  
Vaccinations: 
All prior vaccinations will be collected from 90 days prior to first dose of study drug. Receipt of 
a live, attenuated vaccine within 30 days prior to the first dose of study drug or anticipation that 
such a live, attenuated vaccine will be required during the study treatment period is prohibited. 
Other vaccine types such as inactivated or nucleic acid vaccines (e.g., those given for COVID-19 
or influenza) are permitted if given at one of these timepoints:  
• > 21 days prior to first dose of study drug. In case of COVID-19 vaccinations requiring 
two doses, the second vaccine dose must be given > 21 days prior to first dose of study 
drug.  
• Between C2D1 of chemotherapy (after pre-dose blood sample is obtained) and > 21 days 
prior to definitive surgery 
• After definitive surgery 
 

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10. 
DISCONTINUATION OF STUDY TREATMENT AND PATIENT 
DISCONTINUATION/WITHDRAWAL 
10.1. 
Discontinuation of Study Treatment 
Study drugs will be discontinued if any of the following events occur during the study: 
• A patient suffers an AE that, in the judgment of the Investigator, Sponsor, or Medical 
Monitor, presents an unacceptable risk to the patient 
• General or specific changes in the patient’s condition (e.g., a significant intercurrent 
illness or complication) that, in the judgment of the Investigator, are unacceptable for 
further administration of study drug 
• Occurrence of pregnancy in a female patient during the study 
• Significant noncompliance with protocol requirements 
• The Sponsor or legal representative of the Sponsor requests the patient to withdraw 
• If total time between chemotherapy treatments exceeds a total of >4 weeks, unless 
agreed to by the treating Investigator and Medical Monitor. 
• Where permanent discontinuation of all study drugs is indicated in the toxicity 
management recommendations (Section 9.3).  
Following study drug discontinuation, a Safety Follow-Up and End of Study Visit should be 
completed with assessments performed as shown in the Schedule of Assessments (Table 4). The 
Investigator or designee will document the reason for study drug discontinuation on the 
applicable eCRF. When discontinuation is due to a SAE or a Grade 3 or 4 toxicity considered to 
be related to study drug, the Investigator should follow the event until resolution, return to 
baseline, or it is deemed that further recovery is unlikely. Data on these events should be 
collected on the AE electronic case report form (eCRF). In the event a patient discontinues due 
to pregnancy, the Investigator or designee should notify the Medical Monitor by telephone 
within 24 hours of pregnancy confirmation (see Section 17.3). 
10.2. 
Discontinuation/Withdrawal from the Study 
A patient may withdraw from the study at any time at her own request or may be withdrawn at 
any time at the discretion of the Investigator for safety, behavioral, compliance, or administrative 
reasons. At the time of discontinuing from the study, a Safety Follow-Up and End of Study Visit 
should be completed (if they have not been done already) with assessments performed as shown 
in the Schedule of Assessments (Table 4).  
If the patient withdraws consent for disclosure of future information, the Sponsor may retain and 
continue to use any data collected before such a withdrawal of consent. 
If a patient withdraws from the study, she may request destruction of any samples taken and not 
tested, and the Investigator or designee must document this in the site study records. 

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10.3. 
Lost to Follow Up 
A patient will be considered lost to follow-up if she repeatedly fails to return for scheduled visits 
and is unable to be contacted by the study site. 
In general, a patient is considered lost to follow-up after there are at least 3 documented attempts 
to contact the patient. It is recommended that 1 attempt is via certified letter to the patient. 
10.4. 
Study and Site Start and Closure 
The overall study begins when the first patient signs the ICF. The overall study ends when the 
last patient completes the last study-related phone call or visit, discontinues from the study, or is 
lost to follow-up (i.e., the patient is unable to be contacted by the Investigator). 
A study site is considered eligible to start participation in the study once all regulatory approvals 
are in place, site agreement contract is fully executed, and any other required documents are in 
place as required by Sponsor.  
The Sponsor reserves the right to close a study site(s) or terminate the study at any time for any 
reason. Study sites will be closed upon study completion. A study site is considered closed when 
all required documents and study supplies have been collected, a study-site closure visit has been 
performed, and the site has closed all regulatory activities with the Institutional Review Board 
(IRB)/Independent Ethics Committee (IEC). 
The Investigator may be requested to initiate study-site closure at any time, provided there is 
reasonable cause and sufficient notice is given in advance of the intended termination. Should 
this occur with patients receiving study drug, the patients will transition to receive standard of 
care treatment by their healthcare provider outside of this study. 
Reasons for the early closure of a study site by the Sponsor or Investigator may include but are 
not limited to: 
• Failure of the Investigator to comply with the protocol, the requirements of the 
IRB/IEC or local health authorities, the Sponsor's procedures, or Good Clinical 
Practice (GCP) guidelines 
• Inadequate recruitment of patients by the Investigator 
• Discontinuation of further development of trilaciclib 
If the study is prematurely terminated or suspended, the Sponsor shall promptly inform the 
Investigators, the IECs/IRBs, the regulatory authorities, and any contract research 
organization(s) used in the study of the reason for termination or suspension, as specified by the 
applicable regulatory requirements. The Investigator shall promptly inform the patient and 
should assure appropriate patient therapy and/or follow-up. 
 

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11. 
STUDY ASSESSMENTS  
Study procedures and their timing are summarized in the Schedule of Assessments (Table 4). 
Adherence to the study design requirements, including those specified in the Schedule of 
Assessments, is essential and required for study conduct. Immediate safety concerns should be 
discussed with the Medical Monitor upon occurrence or awareness to determine if the patient 
should continue or discontinue study intervention. 
The Investigator or designee will maintain a screening log to record details of all patients 
screened and to confirm eligibility or record reasons for screening failure, as applicable.  
Patients who discontinue from the study prior to receiving the first dose of study drug may be 
replaced. 
11.1. 
Screening Assessments 
The following information for screening failures should be recorded: patient identification, 
demographic data, and reason for failing the screening process. Patients may only be rescreened 
one time at the discretion of the Investigator. For abnormal laboratory values, a second test to 
confirm the first is permitted; only the qualifying result should be recorded.  
Procedures conducted as part of the patient’s routine clinical management (e.g., hematology, 
serum chemistry, baseline diagnostic tissue) and obtained before signing of the ICF may be 
utilized for screening or baseline purposes provided the procedures met the protocol-specified 
criteria and timeframe. 
11.1.1. 
ER-, PR-, HER2-Negative Status 
Eligibility will be based on local ER-negative, PR-negative, HER2-negative status from a recent 
tumor biopsy report confirming TNBC prior to Screening.  
ER/PR-negative status should be histologically or cytologically confirmed by using an assay 
consistent with local standards (defined as <1% nuclei staining) and HER2 non-overexpressing 
status should be confirmed per 2018 ASCO College of American Pathologists criteria. 
11.1.2. 
Baseline Characteristics and Demographics  
Age (year only), sex, race (when reporting is allowed per local regulations), ethnicity, and 
menopausal status will be collected during the Screening period. 
11.1.3. 
Medical and Surgical History 
Medical and surgical history, including past and current conditions, will be collected. 
Concomitant medications taken from informed consent and vaccinations within 90 days prior to 
the first dose of study drug through the End of Study Visit will be recorded.  
Documentation of TNBC diagnosis and status at baseline must be thoroughly evaluated by the 
Investigator or designee including: date of initial diagnosis, stage at diagnosis, tumor grade, 
primary tumor location and type (i.e., single lesion, multi-centric, multifocal), clinical TNM 
staging at baseline, primary and sentinel lymph node biopsies and results, and BRCA 
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11.2. 
Biomarker and Efficacy Assessments 
To identify novel biomarkers and investigate the immune-based MOA of trilaciclib and its 
impact on the tumor microenvironment, tumor tissue and blood will be collected. Investigations 
may include, but are not limited to:  
1. see Tumor RNA Analyses 
Targeted messenger RNA (mRNA) expression profiling and sequencing in tumor tissue via 
NanoString technologies will be performed to define longitudinal molecular changes within the 
tumor microenvironment and identify gene signatures that correlate to clinical response to 
treatment with trilaciclib and the combinations. Trilaciclib induces a response in tumors that 
likely reflects an inflamed/immune phenotype. Specific immune-related gene sets (such as those 
capturing interferon-gamma signaling, cytotoxicity, inflammatory chemokines, and antigen 
processing) may be evaluated and new signatures may be identified. Individual genes related to 
the immune system may also be evaluated (e.g., interleukin-10, CTLA-4, PD-1, TIGIT, and 
LAG-3).  
2. Immunohistochemistry using Tumor Tissue 
Tumor samples from this study may undergo proteomic analyses via immunohistochemistry 
(IHC) to quantitate cells expressing PD-L1, CD8, and FOXP3, and assess the association with 
response to trilaciclib. Collectively, the data will provide insight into the presence and change in 
TIL infiltration from baseline to post-trilaciclib monotherapy, and at surgery.  
3. Immune Profiling of Peripheral Blood 
Peripheral blood mononuclear cells collection at baseline, on-treatment, and at surgery will be 
characterized by mass cytometry and flow cytometry. Quantitative assessment of major immune 
populations and subsets, cytokine production along with qualitative measurement of cell 
activation, maturation, and exhaustion status, and polyfunctionality will provide a 
comprehensive profile of the peripheral blood immune landscape, and the kinetics of the immune 
response following trilaciclib.  
11.2.1. 
Tumor Biopsy Collection 
To evaluate the impact of trilaciclib on changes of the tumor-associated immune response in 
TNBC, immunophenotypic changes will be compared in tumor biopsies at three separate 
timepoints (Table 4):  
1. Screening: baseline tissue is obtained prior to any study treatment 
2. Trilaciclib Lead-In Phase: on-treatment biopsy is obtained 7 (±1) days post single-dose 
administration of monotherapy trilaciclib (prior to initiation of chemotherapy) 
3. Definitive Surgery: in patients who have not achieved a pCR, tissue will be obtained at 
time of surgery, which is to occur 3-5 weeks after last dose of chemotherapy  
Core needle biopsies should consist of at least 3 separate tumor cores (ideally ≥ 4), utilizing at 
least a 14-gauge needle and multiple passes. Tumor samples will be analyzed from primary 
tumor in breast, not nodal tissue. For fresh biopsies, cores may be stored in paraffin blocks or 
embedded in optimal cutting temperature compound (see laboratory manual for details). 

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Archival tissue may be used for the baseline tissue sample and should consist of representative 
FFPE tumor specimens in paraffin blocks (75-micron). It is the Investigator’s responsibility to 
confirm there is sufficient baseline tissue prior to first dose. If there is insufficient archival tissue, 
a fresh biopsy will be obtained. The patient should not have received any antineoplastic therapy 
(including systemic therapy or radiation) between the baseline tissue collection and first dose of 
study drug. The Sponsor must approve if archival tissue was taken > 30 days from signing 
informed consent. Patients who have adequate archival tissue may consent to optional fresh 
biopsy collection at baseline. 
Tumor tissue will be used to analyze immune endpoints including exploratory markers of 
trilaciclib sensitivity such as genomic profiles, mRNA expression, CDK4/6 dependency, IHC 
staining including PD-L1, among others. Additional details regarding tumor tissue collection, 
processing, handling, and shipping may be found in the laboratory manual. Samples may be 
stored for up to 10 years if patients sign the consent form and allow their samples to be stored for 
any future research.  
11.2.2. 
Blood Collection 
To further evaluate the impact of trilaciclib on the immune response, immunophenotypic 
changes will be compared from serial peripheral blood samples at four separate timepoints 
(Table 4): 
1. Trilaciclib Lead-In Phase: day of single dose monotherapy trilaciclib administration 
(pre-dose) 
2. Trilaciclib Lead-In Phase: day of biopsy, prior to the biopsy procedure and initiation of 
chemotherapy  
3. Treatment Phase: C2D1 of chemotherapy (pre-dose) 
4. Definitive Surgery: day of surgery (prior to surgery); within 3 days of surgery permitted, 
on surgery day preferred. 
Samples may be stored for up to 10 years if patients sign the consent form and allow their 
samples to be stored for any future research. Additional details regarding blood collection, 
processing, handling, and shipping may be found in the laboratory manual. 
11.2.3. 
Pathologic Complete Response 
Definitive surgery such as breast conservation surgery or mastectomy with or without axillary 
lymph node dissection will be performed as part of the local standard of care approximately 3 to 
5 weeks following the completion or early discontinuation of the Treatment Phase. A thorough 
evaluation of breast cancer status, pathological staging per current American Joint Committee of 
Cancer (AJCC) Breast Cancer Staging, and assessment of surgical margins will be performed by 
the local pathologist on all the tissues removed during the surgery. Remaining tissue will be used 
for biomarker analysis. 
pCR is defined as the absence of residual invasive cancer on hematoxylin and eosin evaluation of 
the complete resected breast specimen and all sampled regional lymph nodes following 
completion of neoadjuvant systemic therapy (i.e., ypT0/Tis ypN0 in the current AJCC staging 
system). 

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11.3. 
Safety Assessments  
Unless specified otherwise, safety assessments should be conducted prior to study drug 
administration. 
11.3.1. 
Vital Signs 
The following will be collected per the Schedule of Assessments (Table 4): 
• Pulse rate and blood pressure (diastolic and systolic) 
• Height in centimeters (Screening visit only) and body weight in kilograms  
Assessments may be performed by a physician or other qualified health care provider.  
11.3.2. 
Physical Examination 
Complete physical examination at Screening includes all major body systems, including general 
appearance, skin, neck, eyes, ears, nose, throat, lungs, heart, abdomen, back, lymph nodes, 
extremities, and neurological examinations. Subsequent symptom-directed physical exams 
should include body systems as appropriate (e.g., limited physician exam based on symptoms) 
and weight. 
Information about the physical examination must be present in the source documentation at the 
study site. Clinically relevant findings observed prior to the start of study drug, should be 
recorded as medical history. Clinically relevant findings observed after the start of study drug, 
which meet the definition of an AE, must be recorded on the AE eCRF. 
11.3.3. 
ECOG Performance Status 
The Investigator or designee will assess ECOG performance status during the Screening Period 
to assess for eligibility according to the inclusion and exclusion criteria (Table 10).  
Table 10: 
ECOG Performance Status 
Grade 
ECOG 
0 
Fully active, able to carry on all pre-disease performance without restriction 
1 
Restricted in physically strenuous activity but ambulatory and able to carry out work of 
a light or sedentary nature, e.g., light housework, office work 
2 
Ambulatory and capable of all selfcare but unable to carry out any work activities. Up 
and about more than 50% of waking hours 
3 
Capable of only limited selfcare, confined to bed or chair more than 50% of waking 
hours 
4 
Completely disabled. Cannot carry on any selfcare. Totally confined to be or chair 
5 
Dead 
ECOG=Eastern Cooperative Oncology Group  
Source: Oken, 1982. 

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11.3.4. 
Clinical Safety Laboratory Assessments 
Hematology, serum chemistry, coagulation, and urinalysis will be performed at the site’s local 
certified laboratory per the schedule outlined in the Schedule of Assessments (Table 4). A list of 
clinical laboratory tests to be performed is provided in Section 17.1.  
Hematology may be obtained up to 24 hours and serum chemistry and urinalysis may be 
obtained up to 72 hours prior to each time point on Schedule of Assessments. For women of 
childbearing potential, pregnancy tests will be obtained at Screening and within 72 hours prior to 
chemotherapy treatment on C1D1, C5D1, C11D1, and C16D1 only using serum or urine beta 
human chorionic gonadotropin (ß-hCG). 
Serum chemistry and hematology results shall be reviewed before dosing. Laboratory toxicities 
will be assessed using the NCI CTCAE v5.0. 
An abnormal laboratory value is not an AE unless it is considered to be clinically significant by 
the Investigator. Laboratory parameters for which clinically significant values are noted will be 
re-measured on the appropriate clinical follow-up arranged by the Investigator. Any laboratory 
value that remains abnormal at the end of the study and that is considered clinically significant 
should be followed according to accepted medical standards for up to 30 days or until the values 
return to normal or baseline or are no longer considered clinically significant by the Investigator. 
If such values do not return to normal/baseline within a period of time judged reasonable by the 
Investigator, the etiology should be identified, and the Medical Monitor notified.  
If a subsequent cycle is delayed for toxicity, the patient should still complete the clinical 
laboratory assessments on the scheduled Day 1 (entered as an Unscheduled assessment in the 
eCRF) as well as on the actual first dosing day of that cycle. If the delay is secondary to 
hematologic toxicity, weekly repeat hematology assessments should continue until the finding 
meets criteria for resumption of dosing (see Section 9.2). 
11.3.5. 
Electrocardiogram 
Standard 12-lead electrocardiograms (ECGs) will be performed at Screening (Table 4). 
Additional ECGs may be performed as clinically indicated at any time during the study. All 
12-lead ECGs will be obtained after the patient has been resting for at least 10 minutes in the 
supine position and shall be recorded at 25 mm/sec.  
Any ECG with a QTc value of >500 msec shall have the QTc value confirmed via manual read. 
Following confirmation, the Investigator should follow institutional guidelines for the 
appropriate dose modifications based on the grade of QTc prolongation and evaluate for any 
other potential causes of the prolongation (e.g., concomitant medications). 
The Investigator or designee will review the ECGs locally. 
11.3.6. 
Echocardiogram or MUGA 
An ECHO or MUGA scan will be performed at Screening to evaluate adequate cardiac function 
and determine eligibility (Table 4). The assessment method will be at the Investigator’s 
discretion and per local standard of care. Additional assessments may be performed as clinically 
indicated at any time during the study. If repeat cardiac assessments are necessary, the method 
(ECHO or MUGA) should be the same throughout the study.  

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11.3.7. 
Adverse and Serious Adverse Events 
Study-procedure related SAEs will be collected after the informed consent form is signed; all 
AEs will be collected starting from the first dose of study drug through the End of Study Visit. 
Any AE, either directly or indirectly related to biopsy procedures, surgery, or the medication 
required to perform surgery and its sequelae should be reported. Toxicity will be assessed by 
Investigators using NCI CTCAE v5.0. 
The Investigator and any designees are responsible for detecting, documenting, and recording 
events that meet the definition of an AE or SAE and remain responsible for following up, as 
applicable, AEs that are serious, considered related to the study drugs or study procedures, or 
that caused the patient to discontinue the study or study drugs (see Section 10.1). Patients should 
be encouraged to report AEs freely or in response to general, nondirected questioning. Adverse 
events (serious and non-serious) should be reported on the appropriate page of the eCRF from 
the first dose of study treatment through last patient visit. 
11.3.7.1. Time Period and Frequency for Collecting Adverse and Serious Adverse Event 
Information 
AEs will be collected starting from the first dose of study drug through the End of Study Visit. 
Any SAE occurring between the date the patient signs informed consent and the first dose of any 
study drug, and which the Investigator feels is related to a study specific procedure (i.e., would 
not have occurred unless the patient was on the study), should also be reported. Any AEs that 
occur between the date of signing informed consent and the first dose of study drug should be 
recorded as Medical History. 
All SAEs will be recorded and reported to G1 Therapeutics, Inc Pharmacovigilance (PVG) or 
designee immediately and should not exceed 24 hours after becoming aware of the event, as 
indicated in Section 17.2.  
Investigators are not obligated to actively seek AE or SAE information after 30 days following 
the last dose of study drugs on this study. However, if the Investigator learns of any SAE, 
including a death, at any time after a patient has been discharged from the study, and she 
considers the event to be reasonably related to the study intervention or study participation, the 
Investigator or designee must promptly notify G1 Therapeutics, Inc. PVG or designee. 
11.3.7.2. Method of Detecting Adverse and Serious Adverse Events 
The method of recording, evaluating, and assessing causality of AE and SAE and the procedures 
for completing and transmitting SAE reports are provided in Section 17.2. 
Care should be taken not to introduce bias when detecting AEs and/or SAEs. Open-ended and 
nonleading verbal questioning of the patient is the preferred method to inquire about AE 
occurrences. 
11.3.7.3. Follow-up of Adverse and Serious Adverse Events 
After the initial AE/SAE report, the Investigator is required to proactively follow each patient at 
subsequent visits/contacts. All AEs (both serious and nonserious) will be followed in accordance 
with good medical practice until resolution, return to baseline, or it is deemed that further 
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AE will be recorded in the source document and reported to G1 Therapeutics, Inc. PVG or 
designee. 
All SAEs will be followed until resolution, stabilization, the event is otherwise explained, or the 
patient is lost to follow-up (as defined in Section 10.3). Further information on follow-up 
procedures is provided in Section 17.2. 
11.3.7.4. Regulatory Reporting Requirements for Serious Adverse Events 
Prompt notification of G1 Therapeutics, Inc. PVG or designee by the Investigator (or designee) 
of a SAE is essential so that legal obligations and ethical responsibilities towards the safety of 
patients and the safety of a study intervention under clinical investigation are met. 
G1 Therapeutics, Inc. has a legal responsibility to notify both the local regulatory authority and 
other regulatory agencies about the safety of a study intervention under clinical investigation. G1 
Therapeutics, Inc. will comply with country-specific regulatory requirements relating to safety 
reporting to the regulatory authority, Central IRB/IEC, and Investigators. For all studies, except 
those utilizing medical devices, Investigator safety reports must be prepared for suspected 
unexpected serious adverse reactions (SUSAR) according to local regulatory requirements and 
G1 Therapeutics, Inc. policy and forwarded to Investigators, as necessary. 
An Investigator who receives an Investigator safety report describing a SAE or other specific 
safety information (e.g., summary or listing of SAEs) from G1 Therapeutics, Inc. or designee 
will review and then file it along with the Investigator’s Brochure and will notify the IRB/IEC, if 
appropriate according to local requirements. 
11.3.7.5. Pregnancy 
Details of all pregnancies in female patients will be collected after the start of study intervention 
and until 30 days after the last dose of study drug. 
If a pregnancy is reported, the Investigator or designee should inform G1 Therapeutics, Inc. PVG 
or designee within 24 hours of learning of the pregnancy and should follow the procedures 
outlined in Section 17.3. 
Abnormal pregnancy outcomes (e.g., spontaneous abortion, fetal death, stillbirth, congenital 
anomalies, ectopic pregnancy) are considered SAEs. 
11.3.8. 
Definitive Surgery 
Approximately 3-5 weeks following completion or early discontinuation of the Treatment Phase, 
patients will undergo definitive surgery per local standard of care. Details regarding date of 
surgery, type of surgery, tumor resectability etc. will be recorded in the appropriate eCRF. 
Detailed pathological staging per current AJCC staging criteria and assessment of surgical 
margins will be performed by the local pathologist on all the tissues removed during the surgery 
and recorded in the appropriate eCRF.  

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11.4. 
Safety Monitoring Committee 
An SMC will monitor accumulating safety data and will meet after 10 patients have completed 
2 cycles of doxorubicin/cyclophosphamide, after 10 patients have completed 2 cycles of 
paclitaxel, and at the end of the study (or as defined in the SMC charter). Additional reviews 
may occur. 
A single SMC charter will define the roles and responsibilities of the SMC and its members. 
Additional details regarding the committee’s composition, scope, objectives, procedures, and 
policies, including the associated analysis plan and data to be reviewed for the Sponsor, 
Investigators, and patients, are described in the SMC charter. The SMC will monitor 
accumulating safety and disposition data and will be comprised of study team and independent 
members.  
11.5. 
Safety Follow-up Visit 
The patient should complete a Safety Follow-up Visit 30 days (+7 days) from last dose of study 
drug as outlined in Table 4. This visit may occur at the study site or can be via telephone and 
may coincide with the End of Study Visit.  
11.6. 
End of Study Visit 
The patient should complete an End of Study Visit within 14 days following surgery as outlined 
in Table 4. Pathology results should be recorded if available. The Investigator or designee should 
also ensure that the tumor sample from surgery was provided, if applicable. This visit may occur 
at the study site or can be via telephone and may coincide with the Safety Follow-up Visit.  

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12. 
STATISTICAL CONSIDERATIONS 
A statistical analysis plan (SAP) will be developed and finalized prior to any analysis that will be 
performed for this study. While the SAP will include more details related to the statistical 
analyses for data collected from this study, this section is a summary of the key aspects of the 
planned statistical analyses. 
12.1. 
Sample Size Determination 
Sample size justification is based off of previously published data on the CD8+/Treg ratio from 
early stage TNBC patients who underwent neoadjuvant chemotherapy (Ahn, 2020). Using a 
2-sided significance level of 0.05, and anticipating that 10% patients enrolled to this study will 
not have paired data (resulting in 27 patients with paired data), the power of the study to detect a 
respective mean of paired difference in CD8+/Tregs ratio using paired Wilcoxon signed-rank 
tests has been calculated using PASS 2019 (v19.0.3), and is presented in the table below. 
Mean of Paired Difference in CD8+/Tregs 
Power 
1.8 
72% 
2.0 
81% 
2.3 
90% 
2.5 
94% 
Based on the assumption of an estimated standard deviation of paired differences of 3.4. 
12.2. 
Analysis Population 
The Full Analysis Set - 1 (FAS1) population includes enrolled patients who have received 
trilaciclib during the Trilaciclib Lead-in Phase. This dataset will be used to assess immune 
response in tumor tissue. 
The Full Analysis Set – 2 (FAS2) population includes enrolled patients who have received at 
least one dose of a study drug during the Treatment Phase of the study. This dataset will be used 
to assess safety and tolerability and the rate of pCR for trilaciclib in combination with 
neoadjuvant systemic therapies.  
12.3. 
Statistical Analysis Methods 
12.3.1. 
General Considerations 
All statistical analyses will be performed using SAS® v9.4 or higher.  
The categorical variables will be summarized by counts and percentages, the continuous 
variables will be summarized by mean, median, standard deviations, 25% and 75% percentiles, 
and minimum and maximum values by treatment group. For the immune-response measures and 
other biomarkers, median will be used to present the central point of the population been studied.  
12.3.2. 
Patient Disposition 
Patient disposition will be summarized for all patients. The summary will include number of all 
screened patients, and number and percentage of patients who were enrolled and received study 
drug, discontinued from each study drug and reasons, and discontinued from study and reasons.  

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12.3.3. 
Demographic and Baseline Characteristics 
Demographics and baseline characteristics will be summarized. The summary will include age, 
age groups, gender, race, ethnicity, screening vital signs, ECOG status, region, and baseline 
disease characteristics.  
12.3.4. 
Study Drug Exposure, Modification and Dose Intensity  
Duration of study drug exposure will be defined for each chemotherapy drug (doxorubicin, 
cyclophosphamide, paclitaxel, carboplatin, and pembrolizumab, as applicable) and for trilaciclib.  
The number of cycles that patients have received will be summarized by descriptive statistics as 
a continuous variable, while the number of cycles that are completed will be summarized as a 
categorical variable.  
Study drug modifications will be summarized in three categories: chemotherapy dose reduction, 
cycle delay, and infusion interruption. The number and percentage of patients who have any 
chemotherapy dose reduction or delay and have at least one dose reduction or delay for a 
particular chemotherapy will be summarized along with a summary of the number of dose 
reductions or delays for each chemotherapy; the number and percentage of patients who have at 
least one infusion interruption for trilaciclib, any chemotherapy, or pembrolizumab (if 
applicable) will be summarized along with a summary of the number of interruptions. Lastly, the 
primary reason for each form of study drug modification (chemotherapy dose reductions, cycle 
delay, and infusion interruption) will also be summarized. 
For trilaciclib, doxorubicin, cyclophosphamide, paclitaxel, carboplatin and pembrolizumab 
cumulative dose, dose intensity, relative dose, and relative dose intensity will be derived and 
summarized. 
12.3.5. 
Efficacy Analyses  
12.3.5.1. Analyses for Primary Immune-Response Measure 
Summary statistics for primary immune-response measure, the ratio of CD8+ TIL over FOXP3+ 
regulatory T cells (abbreviated as CD8+/Tregs), will be provided for measures taken at baseline 
(pre-trilaciclib), 7 ± 1 days after single dose trilaciclib (post-trilaciclib), and the change scores 
(post minus pre). Median will be used as the central point with Q1 and Q3 as the measure of 
spread. The significance of the magnitude of change will be tested by paired Wilcoxon Signed-
Rank test. Analyses on the primary endpoint will be based on the FAS1 population. 
12.3.5.2. Analyses for pCR  
For the clinical efficacy endpoint, pCR rate will be reported with a 95% confidence interval 
using the Clopper-Pearson method based on FAS2 population. In addition, patients will be 
dichotomized by median value of changes in CD8+/Tregs ratio, and pCR rate will be 
summarized by the subgroup of patients with high or low change scores. The association 
between pCR status and high/low in ratio change will be tested using a Chi-square test. These 
analyses will be performed on the FAS2 population.  

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12.3.6. 
Safety Analyses  
For trilaciclib alone, safety will be assessed by AE reporting during the Trilaciclib Lead-in Phase 
based on FAS1 population. For trilaciclib in combination with other systemic therapies, safety 
and tolerability will be assessed by AEs, dose modification, laboratory tests, vital signs, and 
ECGs based on FAS2 population. 
12.3.6.1. Adverse Events  
Adverse events are defined as those events occurring or worsening after treatment has begun on 
this study. Adverse event data will be coded to system organ class and preferred term using the 
latest version of Medical Dictionary for Regulatory Activities (MedDRA). The severity (toxicity 
grades 1-5) of AEs will be graded according to the NCI CTCAE Version 5.0 by investigators. 
The number and percentage of patients experiencing any AE overall, and by system organ class, 
preferred term and CTCAE grade will be tabulated. Adverse events considered by the 
Investigator to be related to treatment will also be by study drug (e.g., trilaciclib or each 
chemotherapy). Severity of AEs will be tabulated based on greatest severity observed for each 
patient. In the tabulation of grade and causality, if the same AE occurs on multiple occasions, the 
highest grade and strongest relationship to study drug will be used. AESIs for trilaciclib, AEs 
leading to study drug discontinuation or study drug modification will be summarized by system 
organ class, preferred term and CTCAE grade, as appropriate. Concomitant medications will be 
coded to Anatomical Therapeutic Classification using the World Health Organization-Drug 
Dictionary (WHO-DD) and summarized.  
12.3.6.2. Other Safety Endpoints 
Observed values and changes from baseline in laboratory assessments of hematology and 
chemistry parameters, vital signs, and ECG parameters will be summarized for each scheduled 
visit at which the assessment is taken. Changes from baseline to the maximum and minimum 
values during treatment will also be summarized.  
Clinical chemistry and hematology laboratory parameters will be characterized according to 
CTCAE toxicity grade from 1 to 5, Version 5.0, when possible. The number and percentage of 
patients within each CTCAE grade will be summarized for the overall treatment period as well 
as for each cycle. If a patient has multiple laboratory assessments in an interval of interest, the 
maximum grade will be reported.  
For vital signs and ECG parameters, potentially clinically significant (PCS) findings will be 
summarized. The potentially clinically significant vital signs and ECG measures are defined 
either by post-baseline assessment or by the change from baseline with respect to the pre-
specified thresholds. The criteria defining PCS for vital signs and ECG parameters will be 
detailed in the study SAP.  
12.3.7. 
Exploratory Analyses 
pCR by subgroup analysis will be performed based on PD-L1 status and CDK4/6 dependence 
signatures. Other exploratory analyses to evaluate trilaciclib’s effect on immune response related 
biomarkers and their association with pCR status will be performed as deemed necessary.  
 

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13. 
ETHICS 
13.1. 
Ethics Review 
The protocol, protocol amendments, ICF, IB, and other relevant documents (e.g., advertisements) 
must be submitted to an IRB/IEC by the Investigator and reviewed and approved by the IRB/IEC 
before the study is initiated.  
Any amendments to the protocol will require IRB/IEC approval before implementation of 
changes made to the study design, except for changes necessary to eliminate an immediate 
hazard to study patients. 
The Investigator will be responsible for the following: 
• Providing written summaries of the status of the study to the IRB/IEC annually or 
more frequently in accordance with the requirements, policies, and procedures 
established by the IRB/IEC 
• Notifying the IRB/IEC of SAEs or other significant safety findings as required by 
IRB/IEC procedures 
• Providing oversight of the conduct of the study at the site and adherence to 
requirements of 21 Code of Federal Regulations, International Council for 
Harmonisation (ICH) guidelines, the IRB/IEC, European regulation 536/2014 for 
clinical studies (if applicable), and all other applicable local regulations 
13.2. 
Ethical Conduct of the Study 
This study will be conducted in accordance with the protocol and with the following: 
• Consensus ethical principles derived from international guidelines including the 
Declaration of Helsinki and Council for International Organizations of Medical 
Sciences International Ethical Guidelines 
• Applicable ICH GCP Guidelines 
• Applicable laws and regulations 
13.3. 
Written Informed Consent 
The Principal Investigator(s) at each center will ensure that the patient is given full and adequate 
oral and written information about the nature, purpose, possible risk and benefit of the study. 
Patients must also be notified that they are free to discontinue from the study at any time. The 
patient should be given the opportunity to ask questions and allowed time to consider the 
information provided. 
The patient’s signed and dated informed consent must be obtained before conducting any study 
procedures. 
The Principal Investigator(s) must maintain the original, signed ICF. A copy of the signed ICF 
must be given to the patient or the patient’s legally authorized representative where allowed by 
local regulation. 

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14. 
DATA HANDLING AND RECORDKEEPING 
14.1. 
Data Protection 
Patients will be assigned a unique identifier by the Sponsor. Any patient records or datasets that 
are transferred to the Sponsor will contain the identifier only; patient names or any information 
which would make the patient identifiable will not be transferred.  
The patient must be informed that her personal study-related data will be used by the Sponsor in 
accordance with local data protection law. The level of disclosure must also be explained to the 
patient who will be required to give consent for their data to be used as described in the informed 
consent.  
The patient must be informed that his/her medical records may be examined by Clinical Quality 
Assurance auditors or other authorized personnel appointed by the Sponsor, by appropriate 
IRB/IEC members, and by inspectors from regulatory authorities. 
14.2. 
Data Quality Assurance 
• All patient data relating to the study will be recorded on eCRF unless transmitted to 
the Sponsor or designee electronically. The Investigator is responsible for verifying 
that data entries are accurate and correct by physically or electronically signing the 
eCRF.  
• The Investigator must maintain accurate documentation (source data) that supports 
the information entered in the eCRF.  
• The Investigator must permit study-related monitoring, audits, IRB/IEC review, and 
regulatory agency inspections and provide direct access to source data documents.  
• Monitoring details describing strategy (e.g., risk-based initiatives in operations and 
quality such as Risk Management and Mitigation Strategies and Analytical Risk 
Based Monitoring), methods, responsibilities, and requirements, including handling 
of noncompliance issues and monitoring techniques (central, remote, or on-site 
monitoring) are provided in the Monitoring Plan. 
• The Sponsor or designee is responsible for the data management of this study 
including quality checking of the data.  
• Study Monitors will perform ongoing source data verification (SDV) at the 
frequencies and SDV extent as outlined in the Monitoring Plan to confirm that data 
entered into the eCRF by authorized site personnel are accurate, complete, and 
verifiable from source documents; that the safety and rights of patients are being 
protected; and that the study is being conducted in accordance with the currently 
approved protocol and any other study agreements, ICH GCP, and all applicable 
regulatory requirements.  
• The Investigator must maintain all documentation relating to the study for a period of 
2 years after the last marketing application approval, or if not approved 2 years 
following the discontinuance of the investigation of trilaciclib. If it becomes 
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relating to the study, the Investigator must permit access to such records. No records 
may be destroyed during the retention period without the written approval of the 
Sponsor. No records maybe transferred to another location or party without written 
notification to the Sponsor. The Investigator must ensure that the records continue to 
be stored securely for as long as they are maintained. 
A study-specific COVID-19 Assessment Plan will be utilized for any necessary modifications 
and/or mitigation to the data collection, monitoring or other associated activities during this 
study due to the COVID-19 pandemic. 
14.3. 
Dissemination of Clinical Study Data 
The Sponsor fulfills its commitment to publicly disclose clinical study results through posting 
the results of studies on www.clinicaltrials.gov, the EudraCT, and other public registries in 
accordance with applicable local laws/regulations.  
Data results are posted in an objective, accurate, balanced, and complete manner. Results are 
posted regardless of outcome of the study. 
14.4. 
Source Documents 
Source documents provide evidence for the existence of the patient and substantiate the integrity 
of the data collected. Source documents are filed at the Investigator’s site. All data reported in 
the eCRF should be supported by source documents; direct entry of data into the eCRF is not 
permitted in this study. 
Data reported on the CRF or entered in the eCRF that are transcribed from source documents 
must be consistent with the source documents or the discrepancies must be explained. The 
Investigator may need to request previous medical records or transfer records, depending on the 
study. Also, current medical records must be available. 
14.5. 
Audits and Inspections 
Authorized representatives of G1 Therapeutics, Inc., a regulatory authority, an IEC, or IRB may 
visit the site to perform audits or inspections, including source data verification. The purpose of 
an audit or inspection is to systematically and independently examine all study-related activities 
and documents to determine whether these activities were conducted, and data were recorded, 
analyzed, and accurately reported according to the protocol, GCP guidelines of the ICH, and any 
applicable regulatory requirements. The Investigator should contact G1 Therapeutics, Inc. 
immediately if contacted by a regulatory agency about an inspection. 

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15. 
PUBLICATION POLICY 
By signing the study protocol, the Investigator and his or her institution agree that the results of 
the study may be used by G1 Therapeutics, Inc. for the purposes of national and international 
registration, publication, and information for medical and pharmaceutical professionals. If 
necessary, the authorities will be notified of the Investigator’s name, address, qualifications, and 
extent of involvement. 
Initial publication of the results of this study will be of a cooperative nature that may include 
authors representing the Sponsor, Investigator(s), and collaborating scientists. Independent 
publications by involved individuals may follow. Investigators and their institutions agree not to 
publish or publicly present any interim results of studies without the prior written consent of 
G1 Therapeutics, Inc. G1 Therapeutics, Inc. reserves the right to request modification of any 
publication, presentation or use by the Investigator if such activity may jeopardize a patent 
application, an existing patent, or other proprietary rights. G1 Therapeutics, Inc. shall determine 
order of authorship of any publication combining all clinical results of this study. 

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16.
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Demaria, S. et al. Development of tumor-infiltrating lymphocytes in breast cancer after 
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Keytruda® (pembrolizumab) Injection Prescribing Information. Merck. 2021 
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CD8+ T cells predicts the response to anti-PD-1 therapy in solid tumors. Clin Cancer Res. 
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17. 
APPENDICES 
17.1. 
Clinical Laboratory Tests 
• The timing and laboratory tests detailed in Schedule of Assessments (Table 4) will be 
performed by a local laboratory.  
• Protocol-specific requirements for inclusion or exclusion of patients are detailed in 
Section 7 of the protocol. 
• Additional tests may be performed at any time during the study as determined 
necessary by the Investigator or required by local regulations 
Table 11: 
Protocol-Specified Safety Laboratory Assessments 
Laboratory Assessment 
Parameters 
Hematology 
WBC 
Hemoglobin 
Platelets 
Absolute neutrophil count 
Serum Chemistry 
Sodium  
Urea 
Magnesium 
Bilirubin 
Potassium 
Phosphorus 
Total protein 
Albumin 
Chloride 
Creatinine 
Aspartate aminotransferase 
 
Bicarbonate 
Calcium 
Alanine aminotransferase 
 
Coagulation 
Prothrombin time and/or international normalized ratio  
Urinalysis 
Semiquantitative dipstick: specific gravity, pH, evaluation of glucose, 
protein, bilirubin, ketones, leukocytes, and hemoglobin 
Microscopic examination (including RBC, WBC, and casts) will be 
performed, if clinically warranted 
Other Tests 
Serum or urine human chorionic gonadotropin (hCG) pregnancy test (for 
WOCBP only) 
hCG=human chorionic gonadotropin; RBC=red blood cell; WBC=white blood cell; WOCBP=woman of 
childbearing potential 

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17.2. 
Adverse Events: Definitions and Procedures for Recording, 
Evaluating, and Follow-up 
17.2.1. 
Definition of AE 
AE Definition 
• 
An AE is any untoward medical occurrence in a patient or clinical study patient, temporally 
associated with the use of study intervention, whether or not considered related to the study 
intervention. 
• 
NOTE: An AE can therefore be any unfavorable and unintended sign (including an abnormal 
laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use 
of study intervention. 
Events Meeting the AE Definition  
• 
Any abnormal laboratory test results (hematology, serum chemistry, or urinalysis) or other safety 
assessments (e.g., ECG, radiological scans, vital signs measurements), including those that worsen 
from baseline, considered clinically significant and require clinical intervention or further 
investigation (beyond ordering a repeat [confirmatory] test) in the medical and scientific judgment 
of the Investigator (i.e., not related to progression of underlying disease) unless they are associated 
with an already reported clinical event, e.g. elevated liver enzymes in a patient with jaundice. 
• 
Exacerbation of a chronic or intermittent pre-existing condition including either an increase in 
frequency and/or intensity of the condition. 
• 
New conditions detected or diagnosed after study intervention administration even though it may 
have been present before the start of the study. 
• 
Signs, symptoms, or the clinical sequelae of a suspected overdose of either study intervention or a 
concomitant medication. Overdose per se will not be reported as an AE/SAE unless it is an 
intentional overdose taken with possible suicidal/self-harming intent. Such overdoses should be 
reported regardless of sequelae. 
Events NOT Meeting the AE Definition  
• 
Any clinically significant abnormal laboratory findings or other abnormal safety assessments 
which are associated with the underlying disease, unless judged by the Investigator to be more 
severe than expected for the patient’s condition. 
• 
The disease/disorder being studied or expected progression, signs, or symptoms of the 
disease/disorder being studied, unless more severe than expected for the patient’s condition. 
• 
Medical or surgical procedure (e.g., endoscopy, appendectomy): the condition that leads to the 
procedure is the AE. 
• 
Situations in which an untoward medical occurrence did not occur (social and/or convenience 
admission to a hospital). 
• 
Anticipated day-to-day fluctuations of pre-existing disease(s) or condition(s) present or detected at 
the start of the study that do not worsen. 

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17.2.2. 
Definition of SAE 
If an event is not an AE per definition above, then it cannot be an SAE even if serious conditions 
are met (e.g., hospitalization for signs/symptoms of the disease under study, death due to 
progression of disease). 
A SAE is defined as any untoward medical occurrence that, at any dose: 
1. Results in death 
2. Is life-threatening 
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, which hypothetically might have caused 
death, if it were more severe. 
3. Requires inpatient hospitalization or prolongation of existing hospitalization 
In general, hospitalization signifies that the patient has been detained (usually involving at least an 
overnight stay) at the hospital or emergency ward for observation and/or treatment that would not have 
been appropriate in the physician’s office or outpatient setting. Complications that occur during 
hospitalization are AEs. If a complication prolongs hospitalization or fulfills any other serious criteria, 
the event is serious. 
Hospitalization for elective treatment of a pre-existing condition that did not worsen from baseline is 
not considered an AE. 
4. Results in persistent disability/incapacity 
• 
The term disability means a substantial disruption of a person’s ability to conduct normal life 
functions. 
• 
This definition is not intended to include experiences of relatively minor medical significance 
such as uncomplicated headache, nausea, vomiting, diarrhea, influenza, and accidental trauma 
(e.g., sprained ankle) which may interfere with or prevent everyday life functions but do not 
constitute a substantial disruption. 
5. Is a congenital anomaly/birth defect 
6. Other situations: 
• 
Medical or scientific judgment should be exercised in deciding whether SAE reporting is 
appropriate in other situations such as important medical events that may not be immediately life-
threatening or result in death or hospitalization but may jeopardize the patient or may require 
medical or surgical intervention to prevent one of the other outcomes listed in the above 
definition. These events should usually be considered serious. 
• 
Examples of such events include invasive or malignant cancers, intensive treatment in an 
emergency room or at home for allergic bronchospasm, blood dyscrasias or convulsions that do 
not result in hospitalization, or development of drug dependency or drug abuse. 
 

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17.2.3. 
Recording and Follow-Up of AE and/or SAE 
AE and SAE Recording 
• 
When an AE/SAE occurs, it is the responsibility of the Investigator to review all documentation 
(e.g., hospital progress notes, laboratory reports, and diagnostics reports) related to the event. 
• 
The Investigator will then record all relevant AE/SAE information in the eCRF. 
• 
It is not acceptable for the Investigator to send photocopies of the patient’s medical records to G1 
Therapeutics, Inc. (or designee) in lieu of completion of the AE/SAE eCRF page or Paper SAE 
Report Form. 
• 
There may be instances when copies of medical records for certain cases are requested by 
G1 Therapeutics, Inc. (or designee). In this case, all patient identifiers, with the exception of the 
patient number, will be redacted on the copies of the medical records before submission to G1 
Therapeutics Inc. (or designee). 
• 
The Investigator will attempt to establish a diagnosis of the event based on signs, symptoms, and/or 
other clinical information. Whenever possible, the diagnosis (not the individual signs/symptoms) 
will be documented as the AE/SAE. 
• 
All SAEs should be reported to G1 Therapeutics, Inc. PVG (or designee) within 24 hours of 
notification on an SAE Form in the eCRF. Any relevant source data related to the SAE should also 
be emailed or faxed to G1 Therapeutics, Inc. PVG (or designee): 
G1 Therapeutics, Inc. Pharmacovigilance 
Email: safetyreporting@g1therapeutics.com 
Fax: +1-984-285-7131 
Assessment of Intensity 
Intensity will be assessed using NCI-CTCAE v5.0 criteria, as follows: 
• 
Grade 1: Mild; asymptomatic or mild symptoms; clinical or diagnostic observations only; 
intervention not indicated. 
• 
Grade 2: Moderate; minimal, local or noninvasive intervention indicated; limiting age-appropriate 
instrumental activities of daily living. 
• 
Grade 3: Severe or medically significant but not immediately life-threatening; hospitalization or 
prolongation of hospitalization indicated; disabling; limiting self-care activities of daily living. 
• 
Grade 4: Life-threatening consequences; urgent intervention indicated. 
• 
Grade 5: Death related to AE. 

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AE and SAE Recording 
Assessment of Causality 
• 
The Investigator is obligated to assess the relationship between study intervention and each 
occurrence of each AE/SAE (Related or Not Related); i.e., is there a “reasonable possibility” the 
study intervention caused the event (yes/no). 
• 
A “reasonable possibility” of a relationship conveys that there are facts, evidence, and/or 
arguments to suggest a causal relationship, rather than a relationship cannot be ruled out. 
• 
The Investigator will use clinical judgment to determine the relationship. 
• 
Alternative causes, such as underlying disease(s), concomitant therapy, and other risk factors, as 
well as the temporal relationship of the event to study intervention administration will be 
considered and investigated. 
• 
The Investigator will also consult the IB and/or Product Information, for marketed products, in 
his/her assessment. 
• 
For each AE/SAE, the Investigator must document in the medical notes that she has reviewed the 
AE/SAE and has provided an assessment of causality. 
• 
There may be situations in which an SAE has occurred and the Investigator has minimal 
information to include in the initial report to G1 Therapeutics, Inc. PVG (or designee). However, it 
is very important that the Investigator always make an assessment of causality for every event 
before the initial transmission of the SAE data to G1 Therapeutics, Inc. PVG (or designee). 
• 
The Investigator may change his/her opinion of causality in light of follow-up information and 
send a SAE follow-up report with the updated causality assessment. 
• 
The causality assessment is one of the criteria used when determining regulatory reporting 
requirements. 
Follow-up of AEs and SAEs 
• 
The Investigator is obligated to perform or arrange for the conduct of supplemental measurements 
and/or evaluations as medically indicated or as requested by G1 Therapeutics, Inc. PVG (or 
designee; SAEs only) to elucidate the nature and/or causality of the AE or SAE as fully as possible. 
This may include additional laboratory tests or investigations, histopathological examinations, or 
consultation with other health care professionals. 
• 
New or updated information will be recorded in the originally completed eCRF. 
• 
The Investigator will submit any new or updated SAE data on the paper SAE Report Form to G1 
Therapeutics, Inc. PVG (or designee) within 24 hours of receipt of the information: 
G1 Therapeutics Inc. Pharmacovigilance 
Email: safetyreporting@g1therapeutics.com 
Fax: +1-984-285-7131 

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17.2.4. 
Reporting of SAEs 
SAE Reporting to G1 Therapeutics (or designee) via an Electronic Data Collection Tool 
• 
The primary mechanism for reporting an SAE to G1 Therapeutics (or designee) will be the 
electronic data collection tool (EDC). 
• 
If the electronic system is unavailable, then the site will use the paper SAE Report Form in order to 
report the event within 24 hours via email or fax (see below for SAE reporting contact 
information). 
• 
The site will enter the SAE data into the electronic system as soon as it becomes available. 
• 
After the study is completed at a given site, the electronic data collection tool will be taken off-line 
to prevent the entry of new data or changes to existing data. 
• 
If a site receives a report of a new SAE from a study patient or receives updated data on a 
previously reported SAE after the electronic data collection tool has been taken off-line, then the 
site should report this information on a paper SAE Report form or notify the Medical Monitor by 
telephone. 
• 
Contact for SAE reporting: 
G1 Therapeutics Pharmacovigilance 
Email: safetyreporting@g1therapeutics.com 
Fax: +1-984-285-7131  
 

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17.3. 
Contraceptive Guidance and Collection of Pregnancy Information 
WOCBP Definition 
Woman of Childbearing Potential  
A woman is considered fertile following menarche and until becoming post-menopausal unless 
permanently sterile (see below). 
If fertility is unclear (e.g., amenorrhea in adolescents or athletes), additional evaluation should be 
considered. 
Women in the following categories are not considered Woman of Childbearing Potential 
1. Premenarchal 
Note: Documentation can come from the site personnel’s review of the patient’s medical 
records, medical examination, or medical history interview. 
2. Premenopausal female with 1 of the following acceptable surgical sterilization 
techniques: complete or partial hysterectomy, bilateral tubal ligation, or occlusion with 
surgery at least 6 months prior to dosing, or bilateral oophorectomy with surgery at least 
2 months prior to dosing. 
3. Postmenopausal female: defined as spontaneous amenorrhea for >12 months prior to 
Screening without alternative cause (e.g., implantable contraceptive, side effect of 
medication, etc.) and a serum follicle stimulating hormone (FSH) within the laboratory’s 
reference range for postmenopausal females. 
• Women taking hormone replacement therapy (HRT) must discontinue HRT at least 
2-4 weeks prior to Screening for accurate assessment of FSH (though exact interval 
will depend on the type and dosage of HRT and should be determined by the 
Principal Investigator). 
Contraception Guidance 
Contraceptive use should be consistent with local regulations regarding the methods of 
contraception for those participating in clinical studies. 
• All females of childbearing potential must have a negative serum or urine β-hCG test 
result at Screening and on Day 1 of each chemotherapy cycle.  
• Females must be either postmenopausal, surgically sterile, or agree to use 
2 concurrent forms of contraception during the study and for 6 months following last 
dose of study drug. Acceptable forms of contraception include: 
− Established use of oral, injected or implanted hormonal methods of contraception 
(stable dose at least 3 months prior to dosing) 
− Intrauterine device or intrauterine system 
− Barrier methods of contraception: condom or occlusive cap (diaphragm or 
cervical/vault caps) with spermicidal foam/gel/film/cream/suppository. Barrier 
methods alone (without spermicide) are not acceptable methods. Likewise, 
spermicide alone is not an acceptable method 

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− Male sterilization prior to Screening with the appropriate post-vasectomy 
documentation (absence of sperm in the ejaculate 6 months after procedure). The 
vasectomized male partner should be the sole partner for the patient 
− True abstinence when this is in line with the preferred and usual lifestyle of the 
patient. Periodic abstinence (e.g., calendar, ovulation, symptothermal, post-
ovulation methods) and withdrawal are not acceptable methods of contraception 
• For patients who are exclusively in same-sex relationships, contraceptive 
requirements do not apply. If a patient who is in a same-sex relationship at the time of 
signing the ICF becomes engaged in a heterosexual relationship, they must agree to 
use contraception as described previously. If a patient who is abstinent at the time of 
signing the ICF becomes sexually active, they must agree to use contraception as 
described above. 
In addition, patients are to comply with the following guidelines: 
• Contraceptive use is required for the duration of the study and for at least 6 months 
after the last dose of study drug. 
Collection of Pregnancy Information 
• The Investigator or designee will collect pregnancy information on any female patient 
who becomes pregnant while participating in this study. The initial Information will 
be recorded on the Pregnancy Reporting and Outcome Form (Pregnancy – Initial 
Report Form) and submitted to G1 PVG or designee within 24 hours of learning of a 
patient’s pregnancy within 24 hours of learning of a patient’s pregnancy.  
• The patient will be followed to determine the outcome of the pregnancy. The 
Investigator or designee will collect follow-up information on the patient and the 
neonate and the information will be collected on the Pregnancy – Follow-up Report 
Form and forwarded to G1 Therapeutics, Inc. PVG or designee. Generally, follow-up 
will not be required for longer than 12 weeks beyond the estimated delivery date. Any 
termination of pregnancy will be reported, regardless of fetal status (presence or 
absence of anomalies) or indication for the procedure. 
• While pregnancy itself is not considered to be an AE or SAE, any pregnancy 
complication or elective termination of a pregnancy for medical reasons will be 
reported as an AE or SAE. A spontaneous abortion (occurring at <22 weeks 
gestational age) or still birth (occurring at >22 weeks gestational age) is always 
considered to be an SAE and will be reported as such. Any post-study pregnancy 
related SAE considered reasonably related to the study intervention by the 
Investigator will be reported to G1 Therapeutics, Inc. PVG or designee. While the 
Investigator is not obligated to actively seek this information in former study patients, 
he or she may learn of an SAE through spontaneous reporting. 

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• Any female patient who becomes pregnant while participating in the study will 
discontinue study intervention. 
Contact for Pregnancy reporting: 
G1 Therapeutics Inc. Pharmacovigilance 
Email: safetyreporting@g1therapeutics.com  
Fax: +1-984-285-7131