A Phase 2, Multicenter, Open-Label Study of DKN-01 in Combination With Tislelizumab ± Chemotherapy as First-Line or Second-Line Therapy in Adult Patients With Inoperable, Locally Advanced or Metastatic Gastric or Gastroesophageal Junction Adenocarcinoma (DisTinGuish)
Phase: PHASE2
Conditions: Gastric Cancer, Gastric Adenocarcinoma, GastroEsophageal Cancer
Sponsor: Leap Therapeutics, Inc.

Leap Therapeutics, Inc. 
Protocol 
•
Protocol Title: A Phase 2, Multicenter, Open-Label Study of DKN-01 in Combination
with Tislelizumab ± Chemotherapy a First-Line or Second-Line Therapy in Adult
Patients with Inoperable, Locally Advanced or Metastatic Gastric or
Gastroesophageal Junction Adenocarcinoma (DisTinGuish)
•
Version: 6.0, 29 June 2023
•
Protocol Identifier: DEK-DKK1-P205
•
NCT04363801

Leap Therapeutics, Inc. 
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Amendment 6, v6.0, 29 June 2023 
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1 
CLINICAL STUDY PROTOCOL 
TITLE PAGE 
Protocol Title: 
A Phase 2, Multicenter, Open-Label Study of DKN-01 in 
Combination with Tislelizumab ± Chemotherapy as 
First-Line or Second-Line Therapy in Adult Patients with 
Inoperable, Locally Advanced or Metastatic Gastric or 
Gastroesophageal Junction Adenocarcinoma (DisTinGuish) 
Protocol Identifier: 
DEK-DKK1-P205 
Phase: 
2 
Investigational Product(s): 
DKN-01 (Leap Therapeutics, Inc.) 
Tislelizumab (BGB A317) (BeiGene, Ltd.)  
Indication: 
Inoperable, locally advanced or metastatic gastric or 
gastroesophageal junction adenocarcinoma 
IND Number: 
 (Leap Therapeutics, Inc.) 
 (BeiGene, Ltd.) 
EU CT Number 
2023-504940-32-00 
Sponsor: 
Leap Therapeutics, Inc. 
47 Thorndike Street, Suite B1-1 
Cambridge, MA 02141 
 
Sponsor Signatory 
 
 
 
Original Protocol Version 1.0: 
19 March 2020 
Protocol Version 2.0: 
12 April 2021 
Protocol Version 3.0: 
31 August 2021 
Protocol Version 4.0: 
27 May 2022 
Protocol Version 5.0: 
16 November 2022 
Protocol Version 5.1  
Germany Specific: 
Protocol Version 6.0: 
 
29 March 2023 
29 June 2023 

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FINAL PROTOCOL APPROVAL SHEET 
 
A Phase 2, Multicenter, Open-Label Study of DKN-01 in Combination with Tislelizumab ± 
Chemotherapy as First-Line or Second-Line Therapy in Adult Patients with Inoperable, Locally 
Advanced or Metastatic Gastric or Gastroesophageal Junction Adenocarcinoma (DisTinGuish) 
 
 
 
 
 
 
__
_ 
Date 

Leap Therapeutics, Inc. 
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Amendment 6, v6.0, 29 June 2023 
Confidential 
3 
 
  
INVESTIGATOR SIGNATURE PAGE 
Protocol Title: 
A Phase 2, Multicenter, Open-Label Study of DKN-01 in Combination with 
Tislelizumab ± Chemotherapy as First-Line or Second-Line Therapy in Adult 
Patients with Inoperable, Locally Advanced or Metastatic Gastric or 
Gastroesophageal Junction Adenocarcinoma (DisTinGuish) 
Protocol Identifier:  DEK-DKK1-P205 
This protocol is a confidential communication of Leap Therapeutics, Inc. and BeiGene, Ltd. and its 
subsidiaries. This document is for use by individuals and their designated representatives for their 
confidential review, consideration, and/or participation in investigational trial(s). This document may not 
be copied or distributed for review by any unauthorized individuals without the prior written 
authorization of Leap Therapeutics, Inc. or BeiGene, Ltd. and one of its subsidiaries. I confirm that I 
have read this protocol, I understand it, and I will work according to this protocol and the terms of the 
clinical study agreement governing the study. I will also work consistently with the ethical principles 
that have their origin in the Declaration of Helsinki and that are consistent with good clinical practices 
and the applicable laws and regulations. Acceptance of this document constitutes my agreement that no 
unpublished information contained herein will be published or disclosed without prior written approval 
from Leap Therapeutics, Inc. and BeiGene, Ltd. or one of its subsidiaries. 
Instructions for Investigator: Please SIGN and DATE this signature page prior to implementation of 
this Sponsor-approved protocol. PRINT your name, title, and the name and address of the center in 
which the study will be conducted.  
I have read this protocol in its entirety and agree to conduct the study accordingly: 
 
Signature of Investigator: 
_______________________________ 
Date: 
_____________ 
Printed Name: 
_______________________________ 
Investigator Title: 
_______________________________ 
Name/Address of Center: 
_______________________________ 
 
_______________________________ 
 
_______________________________ 
 
_______________________________ 

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TABLE OF CONTENTS 
TITLE PAGE ................................................................................................................... 1 
FINAL PROTOCOL APPROVAL SHEET ..................................................................... 2 
INVESTIGATOR SIGNATURE PAGE .......................................................................... 3 
TABLE OF CONTENTS ................................................................................................. 4 
SYNOPSIS ……………………………………………………………………………..14 
LIST OF ABBREVIATIONS AND TERMS ................................................................ 33 
1. 
INTRODUCTION ....................................................................................... 37 
1.1. 
Background Information on Gastric and Gastroesophageal Junction 
Adenocarcinoma ......................................................................................... 37 
1.2. 
Current Treatment of G/GEJ Adenocarcinoma and Unmet Clinical Needs 37 
1.2.1. 
Treatment Modalities .................................................................................. 37 
1.2.2. 
Current Treatment of Gastric and Gastroesophageal Junction 
Adenocarcinoma and Unmet Clinical Needs .............................................. 39 
1.3. 
Background Information on the Study Drugs DKN-01 and Tislelizumab . 39 
1.3.1. 
Background Information DKN-01 .............................................................. 39 
1.3.1.1. 
Pharmacology of DKN-01 .......................................................................... 40 
1.3.1.2. 
Toxicology of DKN-01 ............................................................................... 40 
1.3.1.3. 
Clinical Pharmacology of DKN-01 ............................................................. 41 
1.3.1.4. 
Prior Clinical Experience with DKN-01 ..................................................... 43 
1.3.2. 
Background Information on Tislelizumab .................................................. 54 
1.3.2.1. 
Pharmacology of Tislelizumab ................................................................... 54 
1.3.2.2. 
Toxicology of Tislelizumab ........................................................................ 55 
1.3.2.3. 
Clinical Pharmacology of Tislelizumab ...................................................... 55 
1.3.2.4. 
Prior Clinical Experience with Tislelizumab .............................................. 56 
1.4. 
Study Rationale ........................................................................................... 64 
1.4.1. 
Rationale for DKN-01 in the Treatment of Gastric and Gastroesophageal 
Junction Adenocarcinoma ........................................................................... 64 
1.4.2. 
Rationale for Tislelizumab in the Treatment of Gastric and 
Gastroesophageal Junction Adenocarcinoma ............................................. 65 
1.4.3. 
Rationale for the Combination of DKN-01 and Tislelizumab in the 
Treatment of Gastric and Gastroesophageal Junction Adenocarcinoma .... 66 
1.5. 
Justification for Dose .................................................................................. 67 
1.5.1. 
Rationale for DKN-01 Dose in Parts A and B ............................................ 67 

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1.5.2. 
Rationale for DKN-01 Dose for Part C ....................................................... 70 
1.5.3. 
Rationale for Tislelizumab Dose ................................................................. 71 
1.6. 
Benefit-Risk Assessment ............................................................................ 72 
2. 
STUDY OBJECTIVES AND ENDPOINTS .............................................. 74 
2.1. 
Part A and Part B ......................................................................................... 74 
2.1.1. 
Study Objectives ......................................................................................... 74 
2.1.1.1. 
Primary Objective ....................................................................................... 74 
2.1.1.2. 
Secondary Objectives .................................................................................. 74 
2.1.1.3. 
Exploratory Objectives ................................................................................ 74 
2.1.2. 
Study Endpoints .......................................................................................... 75 
2.1.2.1. 
Safety Endpoint ........................................................................................... 75 
2.1.2.2. 
Other Key Safety Endpoints ........................................................................ 75 
2.1.2.3. 
Efficacy Endpoints ...................................................................................... 75 
2.1.2.4. 
Exploratory Endpoints ................................................................................ 76 
2.2. 
Part C ........................................................................................................... 76 
2.2.1. 
Study Objectives ......................................................................................... 76 
2.2.1.1. 
Primary Objective ....................................................................................... 76 
2.2.1.2. 
Secondary Objectives .................................................................................. 77 
2.2.1.3. 
Exploratory Objectives ................................................................................ 77 
2.2.2. 
Study Endpoints .......................................................................................... 78 
2.2.2.1. 
Primary Endpoint ........................................................................................ 78 
2.2.2.2. 
Secondary Endpoints ................................................................................... 78 
2.2.2.3. 
Exploratory Endpoints ................................................................................ 78 
3. 
STUDY DESIGN ........................................................................................ 80 
3.1. 
Summary of Study Design .......................................................................... 80 
3.1.1. 
Treatment .................................................................................................... 81 
3.1.1.1. 
Part A .......................................................................................................... 81 
3.1.1.2. 
Part B ........................................................................................................... 81 
3.1.1.3. 
Part C ........................................................................................................... 83 
3.1.2. 
Pre-Screening (Part B Only) ....................................................................... 85 
3.1.3. 
Screening Period ......................................................................................... 85 
3.1.4. 
Treatment Period ......................................................................................... 86 
3.1.5. 
End of Treatment ......................................................................................... 87 

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3.1.6. 
Safety Follow-up ......................................................................................... 87 
3.1.7. 
PD and Survival Follow-up ......................................................................... 88 
3.2. 
Discontinuation From the Study Treatment or From the Study .................. 88 
3.2.1. 
Patient Discontinuation from Study Treatment ........................................... 88 
3.2.2. 
Patient Discontinuation from Study ............................................................ 89 
3.3. 
End of Study ................................................................................................ 89 
4. 
STUDY POPULATION ............................................................................. 90 
4.1. 
Number of Patients ...................................................................................... 90 
4.2. 
Inclusion Criteria ......................................................................................... 90 
4.2.1. 
Part A and C only ........................................................................................ 90 
4.2.2. 
Part B only ................................................................................................... 90 
4.2.3. 
Part C only ................................................................................................... 91 
4.2.4. 
General ........................................................................................................ 91 
4.3. 
Exclusion Criteria ........................................................................................ 92 
4.3.1. 
Part A and C only ........................................................................................ 92 
4.3.2. 
Part B only ................................................................................................... 93 
4.3.3. 
General ........................................................................................................ 93 
5. 
STUDY TREATMENTS ............................................................................ 97 
5.1. 
Identity of Investigational Products, Packaging, and Handling .................. 97 
5.1.1. 
DKN-01 ....................................................................................................... 97 
5.1.2. 
Tislelizumab ................................................................................................ 97 
5.1.3. 
Oxaliplatin (Part A and C Only) ................................................................. 97 
5.1.4. 
Capecitabine (Part A and C Only) .............................................................. 97 
5.1.5. 
Leucovorin calcium (Part C Only) .............................................................. 98 
5.1.6. 
Fluorouracil (Part C Only) .......................................................................... 98 
5.2. 
Study Drug Administration ......................................................................... 98 
5.2.1. 
Dosing Schedules ........................................................................................ 98 
5.2.1.1. 
DKN-01 ....................................................................................................... 99 
5.2.1.2. 
Tislelizumab ................................................................................................ 99 
5.2.1.3. 
Oxaliplatin – Part A and C only ................................................................ 100 
5.2.1.4. 
Capecitabine – Part A and C only ............................................................. 100 
5.2.1.5. 
Leucovorin calcium and Fluorouracil – Part C only ................................. 100 
5.2.2. 
Order of Administration ............................................................................ 100 

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5.2.2.1. 
Dose Delays .............................................................................................. 101 
5.2.2.2. 
Dose Adjustments ..................................................................................... 102 
5.2.3. 
Criteria for Retreatment ............................................................................ 107 
5.2.3.1. 
Criteria for Initiation of a New Treatment Cycle ...................................... 107 
5.2.3.2. 
Criteria for DKN-01 Treatment on Day 8 or Day 15 of a Treatment Cycle
 ................................................................................................................... 107 
5.3. 
Prior and Concomitant Therapy ................................................................ 107 
5.3.1. 
Systemic Corticosteroids ........................................................................... 108 
5.3.2. 
Radiation Therapy ..................................................................................... 108 
5.3.3. 
Prohibited Concomitant Medications/Procedures ..................................... 108 
5.3.4. 
Restricted Concomitant Medications/Procedures ..................................... 109 
5.4. 
Blinding ..................................................................................................... 109 
5.5. 
Randomization .......................................................................................... 109 
5.6. 
Assessment of Treatment Compliance ...................................................... 109 
5.6.1. 
Study Treatment Diary .............................................................................. 110 
6. 
STUDY ASSESSMENTS AND PROCEDURES .................................... 111 
6.1. 
General Considerations ............................................................................. 111 
6.1.1. 
Visit Windows ........................................................................................... 111 
6.1.2. 
Unscheduled Visits .................................................................................... 112 
6.2. 
Screening and Eligibility ........................................................................... 112 
6.2.1. 
Informed Consent and Screening Log ....................................................... 112 
6.2.2. 
Demographics, Medical History, and Disease History ............................. 112 
6.2.3. 
Prior and Concomitant Medications/Procedures Review ......................... 113 
6.3. 
Safety Assessments ................................................................................... 113 
6.3.1. 
Physical Examination ................................................................................ 113 
6.3.2. 
Vital Signs and Weight ............................................................................. 113 
6.3.3. 
Electrocardiograms ................................................................................... 114 
6.3.4. 
Eastern Cooperative Oncology Group Performance Status ...................... 114 
6.3.5. 
Safety Laboratory Evaluations .................................................................. 114 
6.3.6. 
Ophthalmic Examinations (Korea only) ................................................... 115 
6.3.7. 
Pulmonary Function Tests (Korea only) ................................................... 115 
6.3.8. 
Thyroid and Pancreatic Tests (Korea only) .............................................. 115 
6.4. 
Tumor Response Evaluations .................................................................... 115 

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6.5. 
Post-Treatment Follow-up and Mortality Assessments ............................ 117 
6.6. 
Pharmacokinetics, Pharmacodynamics, and Biomarker Analyses ............ 117 
6.6.1. 
Blood Sample Collection for Biomarker (Proteome) Analysis ................. 117 
6.6.2. 
Blood Sample Collection for DKK1 ......................................................... 117 
6.6.3. 
Circulating Tumor DNA ........................................................................... 118 
6.6.4. 
Pharmacokinetic Samples ......................................................................... 118 
6.6.5. 
Antidrug Antibodies .................................................................................. 118 
6.6.6. 
Tumor Biopsy Samples ............................................................................. 119 
6.6.7. 
Biomarkers ................................................................................................ 120 
7. 
SAFETY MONITORING AND REPORTING ........................................ 121 
7.1. 
Risks Associated with Study Drug ............................................................ 121 
7.1.1. 
Risks Associated with Tislelizumab ......................................................... 121 
7.1.2. 
Risks Associated with DKN-01 ................................................................ 121 
7.2. 
General Plan to Manage Safety Concerns ................................................. 121 
7.2.1. 
Eligibility Criteria ..................................................................................... 121 
7.2.2. 
Safety Monitoring Plan ............................................................................. 122 
7.2.3. 
Safety Review Team ................................................................................. 122 
7.3. 
Adverse Events .......................................................................................... 122 
7.3.1. 
Definitions and Reporting ......................................................................... 122 
7.3.2. 
Assessment of Severity ............................................................................. 123 
7.3.3. 
Assessment of Causality ........................................................................... 123 
7.3.4. 
Follow-up of Adverse Events .................................................................... 124 
7.3.5. 
Laboratory Test Abnormalities ................................................................. 125 
7.4. 
Definition of a Serious Adverse Event ...................................................... 125 
7.5. 
Suspected Unexpected Serious Adverse Reaction .................................... 126 
7.6. 
Timing, Frequency, and Method of Capturing Adverse Events and Serious 
Adverse Events .......................................................................................... 126 
7.6.1. 
Adverse Event Recording Period .............................................................. 126 
7.6.2. 
Reporting Serious Adverse Events ............................................................ 127 
7.6.2.1. 
Prompt Reporting of Serious Adverse Events .......................................... 127 
7.6.2.2. 
Completion and Transmission of the Serious Adverse Event Report ....... 128 
7.6.2.3. 
Regulatory Reporting Requirements for Serious Adverse Events ............ 128 
7.6.3. 
Eliciting Adverse Events ........................................................................... 128 

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7.6.4. 
Disease Progression .................................................................................. 129 
7.6.5. 
Deaths ........................................................................................................ 129 
7.6.6. 
Pregnancies ............................................................................................... 129 
7.6.7. 
Expedited Reporting to Health Authorities, Investigators, Institutional 
Review Boards, and Independent Ethics Committees .............................. 129 
7.6.8. 
Assessing and Recording Immune-Related Adverse Events .................... 130 
7.6.9. 
Recording Infusion-Related Reactions ..................................................... 130 
7.6.10. 
Medication Errors ...................................................................................... 130 
7.6.11. 
Overdose ................................................................................................... 130 
7.6.11.1. 
DKN-01 ..................................................................................................... 130 
7.6.11.2. 
Tislelizumab .............................................................................................. 131 
7.6.11.3. 
Oxaliplatin ................................................................................................. 131 
7.6.11.4. 
Capecitabine .............................................................................................. 131 
7.6.11.5. 
Leucovorin calcium ................................................................................... 131 
7.6.11.6. 
Fluorouracil ............................................................................................... 131 
8. 
STATISTICAL CONSIDERATIONS ...................................................... 132 
8.1. 
Part A and Part B ....................................................................................... 132 
8.1.1. 
Sample Size Determination ....................................................................... 132 
8.2. 
Part C ......................................................................................................... 132 
8.2.1. 
Statistical Hypothesis ................................................................................ 132 
8.2.2. 
Sample Size Determination ....................................................................... 132 
8.3. 
Populations for Analyses ........................................................................... 134 
8.4. 
Statistical Analyses ................................................................................... 136 
8.4.1. 
Efficacy Analyses ...................................................................................... 136 
8.4.1.1. 
Part A and B .............................................................................................. 136 
8.4.1.2. 
Part C ......................................................................................................... 136 
8.4.2. 
Safety Analyses ......................................................................................... 137 
8.4.3. 
Other Analyses .......................................................................................... 138 
9. 
SOURCE DOCUMENTS AND ACCESS TO SOURCE 
DATA/DOCUMENTS .............................................................................. 139 
9.1. 
Access to Information for Monitoring ...................................................... 139 
9.2. 
Access to Information for Auditing or Inspections ................................... 139 
10. 
QUALITY ASSURANCE AND QUALITY CONTROL ........................ 140 

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10.1. 
Regulatory Authority Approval ................................................................ 140 
10.2. 
Quality Assurance ..................................................................................... 140 
10.3. 
Study Site Inspections ............................................................................... 140 
10.4. 
Drug Accountability .................................................................................. 140 
11. 
ETHICS/PROTECTION OF HUMAN PATIENTS ................................. 142 
11.1. 
Ethical Standard ........................................................................................ 142 
11.2. 
Institutional Review Board/Independent Ethics Committee ..................... 142 
11.3. 
Protocol Amendments ............................................................................... 142 
11.4. 
Informed Consent ...................................................................................... 143 
11.5. 
Patient and Data Confidentiality ............................................................... 143 
11.6. 
Financial Disclosure .................................................................................. 144 
11.7. 
Data Handling and Record Keeping ......................................................... 144 
11.7.1. 
Data Collection and Management Responsibilities .................................. 144 
11.7.1.1. 
Data Entry in the Electronic Case Report Form ........................................ 144 
11.7.1.2. 
Data Collection .......................................................................................... 145 
11.7.1.3. 
Data Management/Coding ........................................................................ 145 
11.8. 
Data Integrity and In-house Blinding ........................................................ 145 
11.9. 
Study Records Retention ........................................................................... 145 
11.10. 
Protocol Deviations ................................................................................... 147 
11.11. 
Study Report and Publications .................................................................. 147 
11.12. 
Study Continuation Plan ........................................................................... 147 
11.13. 
Study and Study Center Closure ............................................................... 148 
11.14. 
Information Disclosure and Inventions ..................................................... 148 
12. 
REFERENCES .......................................................................................... 150 
APPENDIX 1. SCHEDULE OF ASSESSMENTS .................................................. 158 
Schedule of Activities – Part A .................................................................................... 158 
Schedule of Activities – Part B .................................................................................... 163 
Schedule of Activities – Part C CAPOX Regimen (21-Day Cycle) ............................ 169 
Schedule of Activities – Part C mFOLFOX6 Regimen (14-Day Cycle) ..................... 174 
APPENDIX 2. CLINICAL LABORATORY ASSESSMENTS .............................. 179 
APPENDIX 3. EASTERN COOPERATIVE ONCOLOGY GROUP (ECOG) 
PERFORMANCE STATUS ..................................................................... 180 

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APPENDIX 4. THE RESPONSE EVALUATION CRITERIA IN SOLID TUMORS 
(RECIST) GUIDELINES, VERSION 1.1 ................................................ 181 
APPENDIX 5. PREEXISTING IMMUNE DEFICIENCIES OR AUTOIMMUNE 
DISEASES ................................................................................................ 191 
APPENDIX 6. NEW YORK HEART ASSOCIATION FUNCTIONAL 
CLASSIFICATION .................................................................................. 192 
APPENDIX 7. MANAGEMENT OF POSSIBLE DKN-01-ASSOCIATED 
ADVERSE EFFECTS ............................................................................... 193 
APPENDIX 8. IMMUNE-RELATED ADVERSE EVENT EVALUATION AND 
MANAGEMENT ...................................................................................... 195 
APPENDIX 9. CHRONIC KIDNEY DISEASE EPIDEMIOLOGY 
COLLABORATION (CKD-EPI) EQUATION ........................................ 208 
APPENDIX 10. CONTRACEPTION GUIDELINES AND DEFINITIONS OF 
“WOMEN OF CHILDBEARING POTENTIAL,” “NO CHILDBEARING 
POTENTIAL” ........................................................................................... 209 
APPENDIX 11. NCI-CTCAE V5.0 INFUSION-RELATED REACTIONS ........... 211 
APPENDIX 12. MANAGEMENT OF DKN-01 INFUSION-RELATED 
REACTIONS ............................................................................................ 212 
APPENDIX 13. MANAGEMENT OF TISLELIZUMAB INFUSION-RELATED 
REACTION AND HYPERSENSITIVITY REACTION ......................... 213 
 

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LIST OF TABLES 
Table 1: 
Individual Clinical Studies .......................................................................... 43 
Table 2: 
Summary of Efficacy Results in Patients Treated with DKN-01+Paclitaxel 
in Study DEK-DKK1-P102, Overall and by Dose ...................................... 52 
Table 3: 
Summary of Efficacy Results Among Patients Treated with 
DKN-01+Pembrolizumab ........................................................................... 53 
Table 4: 
Demographics, Baseline Characteristics, Treatment Exposure Duration, and 
Study Follow-up Duration in Pooled Monotherapy Studies ....................... 57 
Table 5: 
Immune-Related Adverse Events of Any Grade Occurring in ≥1% in 
Pooled Monotherapy Studies ...................................................................... 59 
Table 6: 
Treatment-Emergent Fatal Adverse Events Regardless of Causality in 
Pooled Monotherapy Studies ...................................................................... 61 
Table 7: 
Summary of Tumor Response in Study BGB-A317-205 (Efficacy 
Evaluable Analysis Set) .............................................................................. 63 
Table 8:  
Study Treatment Regimens – Part A and B only ........................................ 98 
Table 9:  
Study Treatment Regimen – Part C only .................................................... 98 
Table 10: DKN-01 Dose Adjustments for Parts A and B1 ....................................... 102 
Table 11: DKN-01 Dose Adjustments for Part B2 .................................................... 103 
Table 12: DKN-01 Dose Adjustments for Part C (experimental arm) ...................... 103 
Table 13: Capecitabine Dose Adjustments (Part A and Part C)2 .............................. 105 
Table 14: Oxaliplatin Dose Adjustments (Part A and Part C)2 ................................. 105 
Table 15: Fluorouracil Dose Adjustments (Part C)2 ................................................. 106 
Table 16: Guidance for Duration of Recording New or Worsening Adverse Events in 
All Treatment Arms .................................................................................. 127 
Table 17: Timeframes and Documentation Methods for Reporting Serious Adverse 
Events to the Sponsor or Designee ............................................................ 127 
Table 18: Treatment Modifications for Symptoms of Infusion-Related Reactions Due 
to Study Drug(s) ........................................................................................ 213 
 
LIST OF FIGURES 
Figure 1: 
Spider Plot of Percent Change in Target Lesion Measurements, Based on 
RECIST v1.1, Among Patients Treated with DKN-01 Monotherapy, by 
Tumor Type (Evaluable Patients) ............................................................... 49 
Figure 2: 
Sum of Diameters Percent Change from Baseline – Monotherapy (Central 
Review) ....................................................................................................... 50 

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Figure 3: 
Best Percent Change in Sum of Diameters – Monotherapy (Central Review)
 ..................................................................................................................... 51 
Figure 4: 
In Vivo Antitumor Activity of Murine Surrogate DKN-01 is Additive with 
an Anti-PD-1 Antibody ............................................................................... 67 
Figure 5: 
Predicted Maximal Free Serum DKK1 (Cmax) Concentrations after 300 mg 
DKN-01 IV Dosing Administered Once Every Two Weeks (Q2W) .......... 69 
Figure 6: 
Predicted Maximal Free Serum DKK1 (Cmax) Concentrations after 600 mg 
DKN-01 IV Dosing Administered Once Every Two Weeks (Q2W) .......... 69 
Figure 7: 
Dosing Interval DKN-01 Trough Concentrations (Dose = 300 mg) ........... 70 
Figure 8: 
Study Design Part A .................................................................................... 81 
Figure 9: 
Study Design Part B1 .................................................................................. 82 
Figure 10: Study Design Part B2 .................................................................................. 82 
Figure 11: Study Design Part C (CAPOX regimen) ..................................................... 84 
Figure 12: Study Design Part C (mFOLFOX6 regimen) .............................................. 84 

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SYNOPSIS 
Name of Sponsor/Company: Leap Therapeutics, Inc. 
Investigational Product: 
DKN-01 (Leap Therapeutics, Inc.) 
Tislelizumab (BGB-A317) (BeiGene, Ltd.) 
Title of Study: 
A Phase 2, Multicenter, Open-Label Study of DKN-01 in Combination with 
Tislelizumab ± Chemotherapy as First-Line or Second-Line Therapy in Adult 
Patients with Inoperable, Locally Advanced or Metastatic Gastric or 
Gastroesophageal Junction Adenocarcinoma (DisTinGuish) 
Protocol Identifier:  
DEK-DKK1-P205 
Phase of Development:  
2 
Number of Patients: Approximately 232 participants (hereafter referred to as patients) will be 
enrolled to ensure a minimum of 220 evaluable patients. Expected enrollment in each cohort as 
follows: 
• 
Part A: Approximately 24 patients with treatment-naïve inoperable, locally advanced or 
metastatic gastric or gastroesophageal junction (G/GEJ) adenocarcinoma will be enrolled to 
ensure 20 evaluable patients. 
• 
Part B: Approximately 48 patients with previously treated inoperable, locally advanced or 
metastatic Dickkopf-1 (DKK1)-high G/GEJ adenocarcinoma will be enrolled to ensure 
40 evaluable patients. 
• 
Part C: Approximately 160 patients with treatment-naïve inoperable, locally advanced or 
metastatic G/GEJ adenocarcinoma will be randomized and enrolled in 2 treatment groups to 
ensure 80 evaluable patients per treatment group. 
Study Centers: Approximately 55 centers, including, but not limited to the United States, Republic of 
Korea, Germany, and United Kingdom. 
Part A and Part B: 
Primary Study Objective: 
• 
To characterize the safety and tolerability of DKN-01 in combination with tislelizumab ± 
CAPOX (capecitabine + oxaliplatin) in patients with inoperable, locally advanced or 
metastatic G/GEJ adenocarcinoma. 
Secondary Study Objectives: 
• 
Part A: To estimate the objective response rate (ORR) of patients with inoperable, locally 
advanced or metastatic G/GEJ adenocarcinoma treated with DKN-01 in combination with 
tislelizumab + CAPOX as a first-line therapy using Response Evaluation Criteria in Solid 
Tumors version 1.1 (RECIST v1.1). 
• 
Part B: To estimate the ORR of patients with inoperable, locally advanced or metastatic 
DKK1-high G/GEJ adenocarcinoma treated with DKN-01 in combination with tislelizumab as 
a second-line therapy using RECIST v1.1. 
• 
Part A: To estimate duration of response (DoR), duration of complete response (DoCR), 
progression-free survival (PFS), overall survival (OS), duration of clinical benefit (DoCB), 
durable clinical benefit (DCB), disease control rate (DCR), and time to response (TTR) in 

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patients with inoperable, locally advanced or metastatic G/GEJ adenocarcinoma treated with 
DKN-01 in combination with tislelizumab + CAPOX as a first-line therapy. 
• 
Part B: To estimate DoR, DoCR, PFS, OS, DoCB, DCB, DCR, and TTR in patients with 
inoperable, locally advanced or metastatic DKK1-high G/GEJ adenocarcinoma treated with 
DKN-01 in combination with tislelizumab as a second-line therapy. 
Exploratory Study Objectives:  
• 
To characterize the pharmacokinetics (PK) of DKN-01. 
• 
To characterize the PK of tislelizumab. 
• 
To assess the immunogenicity of DKN-01. 
• 
To assess the immunogenicity of tislelizumab. 
• 
To assess predictive, prognostic, and/or pharmacodynamic biomarkers and clinical 
characteristics including any association between response, survival, or other clinical 
outcomes and DKN-01 in combination with tislelizumab ± CAPOX. 
• 
To evaluate biomarkers from patient-derived tumor tissue(s) and/or blood (or blood 
derivative) samples obtained before, during, and/or after treatment with DKN-01 in 
combination with tislelizumab ± CAPOX including assessment of association of these 
biomarkers with clinical outcomes to DKN-01 + tislelizumab ± CAPOX. 
• 
To evaluate exposure-response relationships if the available data permit.  
• 
Part A: To estimate the ORR, BOR, DCB rate and DCR using iRECIST in patients with 
inoperable, locally advanced or metastatic G/GEJ adenocarcinoma treated with DKN-01 in 
combination with tislelizumab + CAPOX as first-line therapy continuing treatment beyond 
the initial assessment of progressive disease. 
• 
Part B: To estimate the ORR, BOR, DCB rate and DCR using iRECIST in patients with 
inoperable, locally advanced or metastatic DKK1-high G/GEJ adenocarcinoma treated with 
DKN-01 in combination with tislelizumab as a second-line therapy continuing treatment 
beyond the initial assessment of progressive disease. 
Safety Endpoint: 
• 
Incidence of treatment-emergent adverse events (TEAEs), Grade ≥3 TEAEs, treatment-related 
TEAEs, treatment-emergent serious adverse events (TESAEs), treatment-related TESAEs, 
and TEAEs leading to study drug discontinuation. 
Other Key Safety Endpoints: 
• 
Incidence of treatment-emergent Grade 3/4 clinical laboratory abnormalities. 
• 
Incidence of treatment-emergent immune-related adverse events (irAEs).  
• 
Incidence of Grade 3/4 and serious treatment-emergent irAEs.  
• 
Incidence of Grade 3/4 and serious infusion-related reactions. 
• 
Changes from baseline in clinical laboratory parameters (serum chemistry and hematology). 
• 
Changes from baseline in vital signs and electrocardiogram (ECG) parameters. 
• 
Shift from baseline in Eastern Cooperative Oncology Group (ECOG) performance status. 
Efficacy Endpoints: 
• 
ORR (the proportion of patients with best overall response of complete response [CR] + 
partial response [PR]), as assessed by the Investigator using RECIST v1.1.  

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• 
DoR, defined as the time from initial response (CR or PR) until radiographically documented 
progressive disease or death due to any cause; progressive disease is defined using RECIST 
v1.1. 
• 
DoCR, defined as the time from initial CR until radiographically documented progressive 
disease or death due to any cause; progressive disease is defined using RECIST v1.1. 
• 
PFS, defined as the time from first study drug dose (i.e., C1D1) to first radiographically 
documented progressive disease, as determined using RECIST v1.1, or death due to any 
cause. 
• 
OS, defined as the time from first study drug dose (i.e., C1D1) to death due to any cause.  
• 
DoCB, defined as the time from the first study drug dose (i.e., C1D1) to the time of 
progressive disease, as determined using RECIST v1.1, or death due to any cause in patients 
who had a best overall response of CR, PR, or SD of ≥6 weeks. 
• 
DCB, defined as DoCB ≥180 days. Patients who have best overall response of PD or those 
having clinical benefit but DoCB lasting <180 days will be considered as “non-DCB.”  
• 
DCR (i.e., CR+PR+ SD at ≥6 weeks), as assessed by the Investigator using RECIST v1.1. 
• 
TTR, defined as the time from the first study drug dose to the assessment date of the BOR of 
either CR or PR. 
Exploratory Endpoints:  
• 
Summary of serum concentrations of DKN-01 or tislelizumab at specified timepoints. 
• 
Incidence of antidrug antibodies (ADAs) to DKN-01 or tislelizumab. 
• 
Predictive, prognostic, and/or pharmacodynamic biomarkers including any association 
between response, survival, or other clinical outcomes and DKN-01 in combination with 
tislelizumab ± CAPOX. 
• 
Biomarkers from patient-derived tumor tissue(s) and/or blood (or blood derivative) samples 
obtained before, during, and/or after treatment with DKN-01 in combination with tislelizumab 
± CAPOX. Biomarkers may include, but are not limited to: 
− DKK1 tumor expression in mRNA by ISH  
− Programmed cell death protein ligand-1 (PD-L1) expression in the tumor 
microenvironment by IHC 
− circulating tumor deoxyribonucleic acid (ctDNA) 
− serum DKK1.  
• 
Exposure-response relationships for DKN-01 as data permit.  
• 
iORR = (number of patients with iCR + iPR)/all patients) based on the Investigator 
assessment and following iRECIST for patients continuing treatment beyond the initial 
assessment of progressive disease. 
Part C: 
Primary Study Objective: 
• 
 To assess whether the addition of DKN-01 to the combination of tislelizumab + 
chemotherapy regimen (CAPOX or mFOLFOX6 [leucovorin calcium, fluorouracil, and 
oxaliplatin]) improves PFS according to the RECIST v1.1 as assessed by the Investigator in 
patients with advanced DKK1-high and overall G/GEJ adenocarcinoma compared to 
tislelizumab + chemotherapy regimen (CAPOX or mFOLFOX6) as a first-line therapy. 

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Secondary Study Objectives: 
• 
To estimate the objective response rate (ORR) according to RECIST v1.1 as assessed by the 
Investigator, the duration of response (DoR), and overall survival (OS) in advanced DKK1-
high and overall G/GEJ adenocarcinoma patients treated with DKN-01 in combination with 
tislelizumab + chemotherapy regimen (CAPOX or mFOLFOX6) compared to tislelizumab + 
chemotherapy regimen (CAPOX or mFOLFOX6) as a first-line therapy.  
• 
To assess whether the addition of DKN-01 to the combination of tislelizumab + chemotherapy 
regimen (CAPOX or mFOLFOX6) improves PFS and ORR according to RECIST v1.1 as 
assessed by the Investigator in patients with CPS ≥5 or CPS <5 advanced DKK1-high and 
overall G/GEJ adenocarcinoma compared to tislelizumab + chemotherapy regimen (CAPOX 
or mFOLFOX6) as a first-line therapy.  
• 
To characterize the frequency of toxicity ≥Grade 3 treatment-related adverse events (TRAE) 
associated with each of the treatment arms. 
Exploratory Study Objectives:  
• 
To assess whether the addition of DKN-01 to the combination of tislelizumab + chemotherapy 
regimen (CAPOX or mFOLFOX6) improves the duration of complete response (DoCR), 
duration of clinical benefit (DoCB), durable clinical benefit (DCB), disease control rate 
(DCR) and time to response (TTR) in advanced DKK1-high and overall G/GEJ 
adenocarcinoma patients compared to tislelizumab + chemotherapy regimen (CAPOX or 
mFOLFOX6) as a first-line therapy. 
• 
To characterize the PK of DKN-01. 
• 
To characterize the PK of tislelizumab. 
• 
To assess the immunogenicity of DKN-01. 
• 
To assess the immunogenicity of tislelizumab. 
• 
To assess predictive, prognostic, and/or pharmacodynamic biomarkers and clinical 
characteristics including any association between response, survival, or other clinical 
outcomes of DKN-01 in combination with tislelizumab + chemotherapy regimen (CAPOX or 
mFOLFOX6) compared to tislelizumab + chemotherapy regimen (CAPOX or mFOLFOX6) 
as a first-line therapy. 
• 
To evaluate exposure-response relationships if the available data permit.  
• 
To estimate the ORR, BOR, DCB rate, and DCR using iRECIST in patients with inoperable, 
locally advanced or metastatic DKK1-high and overall G/GEJ adenocarcinoma treated with 
the combination of tislelizumab + chemotherapy regimen (CAPOX or mFOLFOX6) ± DKN-
01 as first-line therapy continuing treatment beyond the initial assessment of progressive 
disease. 
• 
To assess the concordance between Investigator assessment and central imaging assessment 
for primary and secondary efficacy analyses.  
• 
To assess the concordance between tumor area positivity (TAP) and CPS PD-L1 expression 
for primary and secondary efficacy analyses. 
• 
To evaluate differences between backbone chemotherapy regimens (CAPOX vs mFOLFOX6) 
in combination with tislelizumab ± DKN-01 for primary and secondary efficacy analyses. 
Primary Endpoint:  

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• 
PFS, as determined by the Investigator per RECIST v1.1, of DKN-01 plus tislelizumab + 
chemotherapy regimen (CAPOX or mFOLFOX6) versus tislelizumab + chemotherapy 
regimen (CAPOX or mFOLFOX6) in DKK1-high and in all patients. 
Secondary Endpoints: 
• 
ORR, as determined by the Investigator per RECIST v1.1, of DKN-01 plus tislelizumab + 
chemotherapy regimen (CAPOX or mFOLFOX6) versus tislelizumab + chemotherapy 
regimen (CAPOX or mFOLFOX6) in DKK1-high and all patients. 
• 
DoR, as determined by the Investigator per RECIST v1.1, of DKN-01 plus tislelizumab + 
chemotherapy regimen (CAPOX or mFOLFOX6) versus tislelizumab + chemotherapy 
regimen (CAPOX or mFOLFOX6) in DKK1-high and all patients. 
• 
OS with DKN-01 plus tislelizumab + chemotherapy regimen (CAPOX or mFOLFOX6) 
versus tislelizumab + chemotherapy regimen (CAPOX or mFOLFOX6) in DKK1-high and in 
all patients. 
• 
Incidence of ≥Grade 3 treatment-related adverse events (TRAEs). 
Exploratory Endpoints: 
• 
DoCR using RECIST v1.1. 
• 
DoCB as determined using RECIST v1.1, is defined as the time from the date of 
randomization to the time of progressive disease or death due to any cause, in patients who 
had a best overall response of complete response (CR), partial response (PR), or stable disease 
(SD) of ≥6 weeks. 
• 
DCB, defined as DoCB ≥180 days. Patients who have best overall response of PD or those 
having clinical benefit but DoCB lasting < 180 days will be considered as “non-DCB.” 
• 
DCR (i.e., CR+PR+SD at ≥6 weeks), as assessed by the Investigator using RECIST v1. 
• 
TTR, defined as the time from the date of randomization to the assessment date of the first 
instance of an overall response of CR or PR.  
• 
Summary of serum concentrations of DKN-01 at specified timepoints. 
• 
Summary of serum concentrations of tislelizumab at specified timepoints. 
• 
Incidence of anti-drug antibodies (ADAs) to DKN-01. 
• 
Incidence of ADAs to tislelizumab. 
• 
Serum DKK1, change since baseline at specified timepoints (applicable for patients who 
received DKN-01). 
• 
Exposure-response relationships for DKN-01 as data permit. 
• 
Biomarkers from patient-derived tumor tissue(s) and/or blood (or blood derivative) samples 
obtained before, during, and/or after treatment with DKN-01 plus tislelizumab + 
chemotherapy regimen (CAPOX or mFOLFOX6) versus tislelizumab + chemotherapy 
regimen (CAPOX or mFOLFOX6). Biomarkers may include, but are not limited to: 
- 
DKK1 tumoral mRNA expression by Chromogenic situ hybridization (CISH). 
- 
Programmed cell death protein ligand-1 (PD-L1) expression by IHC. 
- 
Genetics from tumor specimens or circulating tumor deoxyribonucleic acid (ctDNA). 
- 
Serum and plasma for proteomics and additional scientific analyses. 

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• 
iORR = (number of patients with iCR + iPR)/all patients) based on the Investigator 
assessment and following iRECIST for patients continuing treatment beyond the initial 
assessment of progressive disease. 
• 
A concordance comparison between Investigator assessment and central imaging assessment 
for primary and secondary efficacy analyses will be performed. 
• 
A concordance comparison between CPS and TAP will be performed, including additional 
scientific analysis in patients with TAP ≥5 or TAP <5 advanced DKK1-high and overall 
G/GEJ adenocarcinoma compared to tislelizumab + chemotherapy regimen (CAPOX or 
mFOLFOX6) as a first-line therapy. 
Study Design: 
This is a Phase 2 open-label, multicenter study to be conducted concurrently in 3 parts (non-
randomized Parts A and B and a randomized Part C).  
• 
Part A will enroll G/GEJ adenocarcinoma patients who have received no prior systemic 
treatment in the locally advanced/metastatic setting (first-line treatment).  
• 
Part B will enroll patients who received only 1 prior systemic treatment, which must consist 
of a platinum and/or fluoropyrimidine–based therapy (± human epidermal growth factor 
receptor 2 [HER2] therapy if applicable) for locally advanced/metastatic DKK1-high G/GEJ 
adenocarcinoma (second-line treatment).  
• 
Part C will enroll G/GEJ adenocarcinoma patients who have received no prior systemic 
treatment in the locally advanced/metastatic setting (first-line treatment).  
In Parts A and B, approximately 72 adult patients with inoperable, histologically confirmed locally 
advanced or metastatic G/GEJ adenocarcinoma with measurable disease (RECIST v1.1) requiring 
therapy will be enrolled in the study.  
Both Parts A and B are designed to evaluate safety, tolerability, and efficacy of the combination 
therapy of IV DKN-01 and tislelizumab ± CAPOX in G/GEJ adenocarcinoma patients. Treatment 
continues in repeating 21-day cycles until patient meets criteria for discontinuation or is no longer 
deriving clinical benefit. Parts A and B will be enrolled concurrently. A review by the Safety Review 
Team (SRT) will occur in each study part after the first 5 patients have completed Cycle 1.  
Part C is the open-label, randomized, controlled, 2-arm portion of the study to evaluate the efficacy 
and safety of tislelizumab + chemotherapy regimen (CAPOX or mFOLFOX6) ± DKN-01 in adult 
patients with inoperable, histologically confirmed locally advanced or metastatic G/GEJ 
adenocarcinoma with measurable disease (RECIST v1.1) requiring therapy. Approximately 160 
patients will be randomized in a 1:1 ratio to receive either DKN-01 in combination with tislelizumab 
and chemotherapy regimen (CAPOX or mFOLFOX6) (n=80) or tislelizumab in combination with 
chemotherapy regimen (CAPOX or mFOLFOX6) (n=80). Patients will be assigned to treatment using 
a central stratified block randomization scheme. Patients will be stratified at randomization by the 
following factors: 
• 
DKK1 RNAscope tumor percentage score (TPS) (≥20% vs <20%)  
• 
PD-L1 immunohistochemistry Combined Positive Score (CPS) (≥5 vs <5) 
Randomization may occur up to 3 calendar days prior to C1D1. 
For Part C, a review by the SRT will occur after the first 5 patients on each chemotherapy regimen 
(CAPOX and mFOLFOX6) have completed Cycle 1 from both the experimental group (i.e., DKN-01 
in combination of tislelizumab and chemotherapy regimen) and the control group (i.e., tislelizumab in 
combination with chemotherapy regimen (CAPOX or mFOLFOX6). Enrollment will continue during 

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the safety data review without pause.   
The study consists of a Pre-Screening Period (Part B only), a Screening Period, a Treatment Period, 
and a Follow-up Period. The Follow-up Period includes a follow-up visit approximately 30 days after 
the last dose of study drug and provides for additional long-term follow-up for disease progression (if 
the patient discontinued study drug for a reason unrelated to progressive disease) and for subsequent 
therapies and death (in all patients).  
Part A – First-Line Treatment 
Part A patients will receive IV DKN-01 (300 mg) on Days 1 and 15, IV tislelizumab (200 mg) on 
Day 1, IV oxaliplatin (130 mg/m2) on Day 1, and oral capecitabine (1000 mg/m2 twice daily [BID]) on 
Days 1-15 of each 21-day cycle for a total of 28 doses per cycle. Part A is restricted to patients who 
have not had prior systemic therapy for locally advanced or metastatic disease. Patients may have 
received prior neoadjuvant or adjuvant therapy as long as it was completed without disease recurrence 
for at least 6 months. A review by the SRT will occur after the first 5 patients have enrolled and 
completed Cycle 1. Enrollment in the other ongoing cohorts may continue during the SRT review. 
Part B – Second-Line Treatment 
Part B patients will receive IV DKN-01 (300 mg or 600 mg) on Days 1 and 15 and IV tislelizumab 
(200 mg) on Day 1 of each 21-day cycle.  
Part B has 2 components:  
The first 24 patients (Part B1) will receive DKN-01 300 mg.  
The next 24 patients (Part B2) will receive DKN-01 600 mg. 
Patients enrolled in Part B are required to have DKK1-high (H-score ≥35) G/GEJ adenocarcinoma 
(pre-screen biopsy) and must have had only 1 prior systemic therapy for locally advanced/metastatic 
disease (platinum and/or fluoropyrimidine-based therapy; ± HER2 therapy if applicable). Patients may 
have received prior neoadjuvant or adjuvant therapy. A review by the SRT will occur after the first 
5 patients in each of Part B1 and B2 have enrolled and completed Cycle 1.  
It is anticipated that Part B2 will enroll following the completion of enrollment of all patients in Part 
B1. Enrollment in the other ongoing cohorts (e.g., Part A) may continue during the SRT review.  
Part C – First-Line Treatment 
Part C patients will be randomized using a central stratified block randomization scheme into one of 
2 groups: patients in the experimental group will receive DKN-01 in combination with tislelizumab 
and chemotherapy regimen (CAPOX or mFOLFOX6) and patients in the control group will receive 
only tislelizumab in combination with chemotherapy regimen (CAPOX or mFOLFOX6). The 
randomization will use the following stratification factors: 
• 
DKK1 RNAscope TPS (≥20% vs <20%)  
• 
PD-L1 immunohistochemistry CPS (≥5 vs <5) 
Note: To avoid unnecessary delays which could impact patient care, during the Screening Period 
patients, who in the opinion of the Investigator are unable to wait more than 2 weeks to start 
treatment, may receive one cycle of chemotherapy (CAPOX or mFOLFOX6) prior to randomization 
while awaiting biomarker results. Patients meeting these requirements should be discussed with the 
Medical Monitor. 
Once DKK1 and PD-L1 results from the central laboratory are received and the patient has been 
confirmed to meet all other eligibility requirements, the patient will be randomized to receive either 
DKN-01 in combination with tislelizumab and chemotherapy (CAPOX or mFOLFOX6) or 

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tislelizumab in combination with chemotherapy (CAPOX or mFOLFOX6). The chemotherapy 
regimen administered during Screening must be equivalent to that following randomization.  
The enrollment assumptions will be monitored during the enrollment period; thus sample size and 
timeline could be adjusted accordingly. 
Patients in both groups receiving the CAPOX chemotherapy regimen will receive tislelizumab 
(200 mg, IV) on Day 1 of each 21-day cycle. The CAPOX regimen will include oxaliplatin 130 mg/m2 
on Day 1 and capecitabine 1000mg/m2 BID on Days 1-15 of each 21-day cycle for a total of 28 doses. 
Patients in the experimental group will receive DKN-01 (600 mg, IV) on Day 1 of each cycle. For 
Cycle 1 only, an additional loading dose of DKN-01 (600 mg, IV) will be administered on Day 15. 
Patients in the control group will not receive DKN-01 treatment. 
Patients in both groups receiving the mFOLFOX6 chemotherapy regimen will receive tislelizumab 
(400 mg, IV) every 6 weeks starting on C1D1 and continuing every third 14-day cycle (e.g., C4D1, 
C7D1, etc.). The mFOLFOX6 regimen will be administered every 14 days and includes leucovorin 
calcium (folinic acid) 400 mg/m2 IV on Day 1, fluorouracil 400 mg/m2 IV bolus on Day 1 followed 
by fluorouracil 2400 mg/m2 IV continuous infusion over 48 hours, and oxaliplatin 85 mg/m2 IV on 
Day 1. Patients in the experimental group will receive DKN-01 (400 mg, IV) on Day 1 of each cycle. 
For Cycle 1 only, an additional loading dose of DKN-01 (400 mg, IV) will be administered on Day 8. 
Patients in the control group will not receive DKN-01 treatment. 
For Part C, a review by the SRT will occur after the first 5 patients on each chemotherapy regimen 
(CAPOX and mFOLFOX6) have completed Cycle 1 from both the experimental group (i.e., DKN-01 
in combination of tislelizumab and chemotherapy regimen) and the control group (i.e., tislelizumab in 
combination with chemotherapy regimen [CAPOX or mFOLFOX6]). Enrollment will continue during 
the safety data review without pause. 
Safety Assessments: 
Safety will be evaluated by assessment of adverse events (AEs), ECOG performance status, vital 
signs, ECG, physical examinations, ADA, and clinical laboratory values.  
Toxicities will be graded and documented according to the National Cancer Institute Common 
Terminology Criteria for Adverse Events (NCI-CTCAE v5.0 guidelines). 
The Investigator will determine grade, severity, seriousness, and relationship of the event to the study 
treatment. 
Efficacy Assessments: 
Radiological Assessment 
Radiological assessment of tumor-response status will be performed approximately every 6 weeks (± 
7 days) after C1D1 for the first 24 weeks, then every 9 weeks (± 7 days) after 24 weeks based on 
RECIST v1.1. Tumor response will be assessed by the Investigator. 
Tumor response and progression will also be assessed using the Immune-related Response Criteria 
(iRECIST), 2017 for any patients continuing treatment after the initial assessment of progressive 
disease using RECIST 1.1. 
Patients should have the same radiographic imaging modality used throughout the study (at baseline 
and at subsequent assessments) in order to provide uniformity of radiographic assessments. 
After first documentation of response (CR or PR), confirmation of tumor response should occur at a 
minimum of 4 weeks after the first response or at the next scheduled assessment time point. 
Radiological images will be read locally and then sent to a central imaging vendor (Part C only). The 

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Sponsor may have the central imaging vendor perform an independent evaluation of some or all of the 
radiological images in Part C. 
Tumor Biopsy 
A tumor sample (fresh biopsy [preferred] or archived specimen) will be obtained from all patients 
during Pre-screening (Part B only) and Screening and will be sent to the Sponsor-designated central 
laboratory.  
For Part B, the biopsy sample (fresh [preferred] or archival) collected during the Pre-screening period 
will be used to confirm elevated DKK1 mRNA levels required to meet eligibility criteria for 
enrollment. A fresh biopsy will be collected during the Screening period from patients who did not 
undergo a biopsy during the Pre-screening period for evaluation of DKK1 mRNA levels (unless it is 
clinically contraindicated per Investigator and after consultation with the Medical Monitor) for a 
retrospective DKK1 mRNA analysis.  
For all Part A and B patients with fresh biopsies, the patient’s biopsy sample obtained during the 
Screening Period will be sent to the Sponsor-designated central laboratory for retrospective evaluation 
of DKK1 expression.  
All DKK1 testing will be conducted with a proprietary CISH assay using RNAscope technology at 
Flagship Biosciences, Inc. Westminster, CO, a CAP-accredited and Clinical Laboratory Improvement 
Amendments (CLIA)-certified laboratory. For Part C, PD-L1 expression will also be conducted by 
Flagship Biosciences. If the central lab is unable to result a PD-L1 CPS score, historical CPS data can 
be used provided it was generated using either the 22C3 pharmDx, 28-8 pharmDx or SP263 assays. 
For both Parts A and B, PD-L1 expression will be retrospectively assessed if sufficient tumor biopsy 
tissue is available. In Part A, B, and C, scientific analyses, including microsatellite status (e.g., 
microsatellite stable [MSS], microsatellite instability-low [MSI-L], or microsatellite instability-high 
[MSI-H]), genomic profiling, RNA profiling (e.g., RNA-Seq), immunohistology, Epstein Barr virus 
(EBV), infiltrating immune cells by IHC, and additional IHC analyses may be performed.  
For Part C patients, DKK1 testing and PD-L1 expression will be prospectively analyzed to permit 
stratification prior to randomization. DKK1 expression will be assessed using a Tumor Percentage 
Score (TPS). TPS has demonstrated significant correlation with H-score in retrospective analysis.  
For Part C patients, an on-treatment biopsy is required if clinically feasible at Day 21 (+ 7 days). If 
possible, this should come from the same lesion used for the Screening analysis. If the original lesion 
is no longer measurable then a biopsy from another lesion is acceptable. Additional tumor tissue 
collected at any time during the study per standard of care may be submitted to the central laboratory 
for evaluation. Any on-treatment biopsy tissue will be sent to the Sponsor-designated central 
laboratory for evaluation of DKK1 expression and other biomarkers of interest.  
An additional biopsy to evaluate the effects of treatment on the tumor tissue may be collected at any 
time during the study if a repeat biopsy is required clinically and the patient consents to the biopsy. 
Duration of Patient Participation and Treatment: 
A patient’s study participation will include a 28-day Screening period (35 days allowed for imaging in 
Part C), followed by the study treatment period that will continue until the development of 
radiographically documented progressive disease, unacceptable toxicity or another discontinuation 
criterion is met, as determined by the Investigator, or until a patient reaches 2 years of treatment as 
outlined below (as measured from C1D1). After treatment discontinuation, patients will enter a long 
term follow-up period. The Sponsor has the right to terminate this study at any time.  
If, in the opinion of the Investigator, a Part A patient is receiving clinical benefit from treatment with 
the combination of DKN-01 plus tislelizumab plus CAPOX but has a compelling clinical reason after 
completion of Cycle 2 to discontinue oxaliplatin, capecitabine, and/or tislelizumab treatment, the 
patient will be permitted to continue in the study with DKN-01 monotherapy or any combination of 

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DKN-01 + other study drugs (e.g., oxaliplatin, capecitabine and/or tislelizumab) at the discretion of 
the treating clinician, after discussion with the Medical Monitor.  
If, in the opinion of the Investigator, a Part B patient is receiving clinical benefit from treatment with 
the combination of DKN-01 plus tislelizumab but has a compelling clinical reason after completion of 
Cycle 2 to discontinue tislelizumab treatment, the patient will be permitted to continue in the study 
with DKN-01 monotherapy at the discretion of the treating clinician, after discussion with the Medical 
Monitor.  
If, in the opinion of the Investigator, a Part C (experimental arm only) patient is receiving clinical 
benefit from treatment with the combination of DKN-01 plus tislelizumab plus CAPOX/ mFOLFOX6 
but has a compelling clinical reason after completion of Cycle 2 to discontinue one or several of the 
combination agents, e.g., oxaliplatin, capecitabine, leucovorin calcium, fluorouracil, DKN-01, and/or 
tislelizumab treatment, the patient will be permitted to continue in the study provided at least one of 
the agents is continued and no new systemic therapies are added at the discretion of the treating 
clinician, after discussion with the Medical Monitor.  
If, in the opinion of the Investigator, a Part C (control arm only) patient is receiving clinical benefit 
from treatment with the combination tislelizumab plus CAPOX/ mFOLFOX6 but has a compelling 
clinical reason after completion of Cycle 2 to discontinue one or several of the combination agents, 
e.g., oxaliplatin, capecitabine, fluorouracil, and/or tislelizumab treatment, the patient will be permitted 
to continue in the study provided at least one of the agents is continued and no new systemic therapies 
are added at the discretion of the treating clinician, after discussion with the Medical Monitor. 
When a patient reaches 2 years of treatment (as measured from C1D1): 
Patients may continue on study drugs beyond 2 years if the Investigator considers this to be in the best 
interest of the patient based on an assessment of clinical benefit and potential risks. Continuation of 
study drugs beyond 2 years must be explicitly approved by the Sponsor and will be contingent on the 
continued availability of tislelizumab and DKN-01. The study assessment and procedure schedule will 
remain the same.  
Patients with confirmed CR, PR, or SD may stop treatment after 2 years if the patient wishes. The 
decision should be based on the Investigator’s evaluation, with the patient’s clinical benefit and risk 
taken into consideration. The Investigator should notify the Sponsor that treatment will be stopped 
prior to stopping the treatment.  
Treatment beyond the initial Investigator-assessed, RECIST v1.1-defined disease progression is 
permitted provided that the patient has Investigator-assessed clinical benefit and is tolerating the study 
drugs. Tumor assessment in such patients should continue as planned until study treatment 
discontinuation. 
Patients who discontinue study treatment early for reasons other than disease progression (e.g., 
toxicity) will continue to undergo tumor assessments every 12 weeks during the PD Follow-up Period 
until the patient begins a subsequent anticancer treatment, experiences disease progression, withdraws 
consent, is lost to follow-up, dies, or until the study terminates, whichever occurs first. After 
documentation of PD, all patients will be followed approximately every 12 weeks per routine clinical 
practice during the Survival Follow-up Period for survival until death, withdrawal of consent, or study 
closure.  
Study Population: Adult patients with inoperable, locally advanced or metastatic G/GEJ 
adenocarcinoma  
Eligibility Criteria: 
Inclusion Criteria: Patients meeting all of the following criteria will be considered eligible for study 
entry: 

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Part A and C only 
1. No previous systemic therapy for inoperable, locally advanced or metastatic G/GEJ 
adenocarcinoma.  
a. Patients may have received prior neoadjuvant or adjuvant therapy as long as it was 
completed without disease recurrence for at least 6 months since last treatment. 
Part B only 
2. Documented objective radiographic or symptomatic disease progression following first-line 
therapy with any platinum and/or fluoropyrimidine-based regimen for unresectable or metastatic 
disease.  
a. Patients may have received prior neoadjuvant or adjuvant therapy. If progression has 
occurred within 6 months from last dose of neoadjuvant or adjuvant treatment, this 
regimen will be considered as 1 line of therapy for advanced disease. 
b. Prior trastuzumab (or biosimilar) treatment is acceptable for patients with history of 
HER2-positive G/GEJ adenocarcinoma. 
c. Prior therapy with an anti-programmed cell death protein 1 (PD-1), anti-PD-L1 in any 
treatment setting (including adjuvant/neoadjuvant) is acceptable. 
3. Documentation of elevated DKK1 mRNA expression in tumor cells from a fresh tumor biopsy 
(preferred) or archived tumor biopsy specimen. High DKK1 is defined as an H-score ≥35 in mRNA 
by ISH conducted in a Sponsor designated central laboratory. 
Part C only 
4. Documentation of PD-L1 CPS by IHC and DKK1 mRNA expression in tumor cells by ISH from 
a fresh tumor biopsy (preferred) or archived tumor biopsy specimen conducted in a Sponsor 
designated central laboratory.  If the central lab is unable to result a PD-L1 CPS score, historical CPS 
data can be used provided it was generated using either the 22C3 pharmDx, 28-8 pharmDx or SP263 
assays. 
General 
5. Able to provide written informed consent and can understand and agree to comply with the 
requirements of the study and the schedule of assessments. 
6. Age ≥18 years on the day of signing the informed consent (exception: ≥19 years in the Republic 
of Korea). 
7. Histologically proven gastric adenocarcinoma or Siewert I-III GEJ adenocarcinoma. 
8. At least one measurable lesion on radiographic imaging as defined by RECIST v1.1.  
a. A lesion in an area subjected to prior loco-regional therapy, including previous 
radiotherapy, is not considered measurable unless there has been demonstrated 
progression in the lesion since the therapy as defined by RECIST v1.1. 
b. Previously irradiated lesions can only be considered as measurable disease if disease 
progression has been unequivocally documented at that site since radiation and the 
previously irradiated lesion is not the only site of disease. 
9. Tumor tissue for mandatory pre-treatment evaluation (fresh biopsy [preferred] or archived 
specimen).  
10. ECOG performance status ≤1 within 7 days of first dose of study drug.  
11. Acceptable liver function: 

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a. Parts A and B only 
i. 
Total bilirubin ≤2.0 times upper limit of normal (ULN). Total bilirubin must be <3 × 
ULN for patients with Gilbert’s syndrome. 
ii. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤3 times ULN 
(if liver metastases are present, then ≤5 × ULN is allowed). 
b. Part C only 
i. 
Total bilirubin ≤2.0 times upper limit of normal (ULN).  
ii. AST and ALT ≤2.5 times ULN.  
1. If liver metastases are present, then ≤5 × ULN is allowed (excluding Republic of 
Korea). 
12. Acceptable renal function: 
a. Serum creatinine ≤1.5 × ULN or estimated glomerular filtration rate 
≥30 mL/min/1.73 m2 by Chronic Kidney Disease Epidemiology Collaboration 
equation. 
13. Acceptable hematologic status (in the Republic of Korea patients must not have required blood 
transfusion or growth factor support within 14 days before sample collection at Screening for the 
following): 
a. Absolute neutrophil count (ANC) ≥1.5 × 109/L. 
b. Platelets: 
i. Part A and C only: ≥100 × 109/L  
ii. Part B only: ≥75 × 109/L 
c. Hemoglobin ≥9 g/dL  
 
 
14. Acceptable coagulation status: 
a. Prothrombin time/activated partial thromboplastin time ≤1.2 × ULN (unless 
receiving anticoagulation therapy; if receiving anticoagulation therapy, 
eligibility will be based upon international normalized ratio [INR]) see (b)(i) 
below 
b. INR ≤1.5 (unless receiving anticoagulation therapy) 
i. If receiving anticoagulant: INR ≤3.0 and no active bleeding (i.e., no 
clinically significant bleeding within 14 days prior to first dose of study 
drugs). 
15. Females of childbearing potential must be willing to use a highly effective method of birth control 
for the duration of the study and for at least 6 months after the last dose of study drugs, and have a 
negative urine or serum pregnancy test within 7 days before first dose of study drugs. 
16. Non-sterile males must be willing to use a highly effective method of birth control for the duration 
of the study and for at least 6 months after the last dose of study drugs 
a. A sterile male is defined as one for whom azoospermia has been previously 
demonstrated in a semen sample examination as definitive evidence of infertility. 
b. Males with known “low sperm counts” (consistent with “sub-fertility”) are not to be 
considered sterile for purposes of this study.  

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Exclusion Criteria: Patients meeting any of the following criteria are not eligible for study entry: 
Part A and C only 
1.  Diagnosis of HER2-positive G/GEJ adenocarcinoma. 
2. Unable to swallow capsules or disease significantly affecting gastrointestinal function such as 
malabsorption syndrome, resection of the stomach or small bowel, bariatric surgery procedures, 
symptomatic inflammatory bowel disease, or partial or complete bowel obstruction (for those 
receiving CAPOX in Part C). 
3. Prior therapy with an anti-programmed cell death protein 1 (PD-1) or anti-PD-L1 antibody. 
Part B only 
4. Systemic anti-cancer therapy (e.g., chemotherapy or immunotherapy) within 21 days prior to first 
dose of study drug. 
General 
5. Squamous cell or undifferentiated or other histological type of gastric cancer. 
6. Prior therapy with an anti-PD-L2 or any other antibody or drug specifically targeting T-cell co-
stimulation or coinhibitory checkpoint pathways in any treatment setting (including 
adjuvant/neoadjuvant) or prior therapy with an anti-DKK1 agent (Part B exception, see entry criterion 
2c). 
7. Active autoimmune diseases or history of autoimmune diseases that may relapse.  
a. Note: Patients with the following diseases are not excluded and may proceed to further 
Screening: 
i. Controlled Type I diabetes 
ii. Hypothyroidism (provided it is managed with hormone replacement therapy only) 
iii. Controlled celiac disease 
iv. Skin diseases not requiring systemic treatment (e.g., vitiligo, psoriasis, alopecia) 
v. Any other disease that is not expected to recur in the absence of external triggering 
factors. 
8. Any condition that required treatment with corticosteroids (≥10 mg per day prednisone or 
equivalent) or other immune suppressive drugs within the 14 days prior to first dose of study drug. 
a. Note: Patients who are currently or have previously been on any of the following steroid 
regimens are not excluded: 
i. 
Adrenal replacement steroid (dose ≤10 mg daily of prednisone or equivalent) 
ii. 
Topical, ocular, intra-articular, intranasal, or inhaled corticosteroid with minimal 
systemic absorption 
iii. 
Short course (≤7 days) of corticosteroid prescribed prophylactically (e.g., for 
contrast dye allergy) or for the treatment of a non-autoimmune condition (e.g., 
delayed-type hypersensitivity reaction caused by contact allergen). 
9. Active leptomeningeal disease or uncontrolled brain metastases. Patients with equivocal findings 
or with confirmed brain metastases are eligible for the study provided that they are asymptomatic and 

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radiologically stable without the need for corticosteroid treatment or seizure prophylaxis for ≥4 weeks 
before first dose of study drug.  
10. Any active malignancy ≤2 years before first dose of study drug, with the exception of the specific 
cancer under investigation in this study and any locally recurring cancer that has been treated 
curatively (e.g., resected basal or squamous cell skin cancer, superficial bladder cancer, carcinoma in 
situ of the cervix or breast). 
11. Uncontrolled diabetes or >Grade 1 laboratory test abnormalities in potassium, sodium, or 
corrected calcium despite standard medical management or ≥Grade 3 hypoalbuminemia within 14 
days before first dose of study drug. 
12. Uncontrollable pleural effusion, pericardial effusion, or ascites requiring frequent drainage within 
7 days prior to first dose of study drug (the cytological confirmation of any effusion is permitted). 
13. Clinically significant anorexia (CTCAE ≥Grade 2) within 7 days prior to first dose of study drug. 
14. History of interstitial lung disease, non-infectious pneumonitis, pulmonary fibrosis, acute lung 
disease, or uncontrolled systemic diseases.  
a. Patients with radiation pneumonitis may be eligible for the study if the radiation 
pneumonitis has been confirmed as stable (beyond acute phase) without any concerns 
about recurrence. Patients with severe but stable radiation-induced pneumonitis may be 
required to undergo routine pulmonary function studies. 
15. Severe chronic or active infections requiring systemic antibacterial, antifungal, or antiviral 
therapy, including tuberculosis infection within 14 days of first dose of study drug. 
16. Prior allogeneic stem cell transplantation or organ transplantation. 
17. History of severe hypersensitivity reactions to other monoclonal antibodies or any components of 
study treatment. 
18. Known dihydropyrimidine dehydrogenase deficiency. 
19. Any of the following cardiovascular risk factors: 
a. Cardiac chest pain, defined as moderate pain that limits instrumental activities of daily 
living, within 28 days before first dose of study drug 
b. Pulmonary embolism within 28 days before first dose of study drug 
c. Any history of acute myocardial infarction within 6 months before first dose of study drug 
d. Any history of heart failure meeting New York Heart Association (NYHA) Classification 
III or IV within 6 months before first dose of study drug 
e. Any event of ventricular arrhythmia ≥Grade 2 in severity within 6 months before first 
dose of study drug 
f. Any history of cerebrovascular accident within 6 months before first dose of study drug 
g. Uncontrolled hypertension that cannot be managed by standard anti-hypertension 
medications within 28 days before first dose of study drug 
h. Any episode of syncope or seizure within 28 days before first dose of study drug. 
20. Fridericia-corrected QT interval >470 msec (female) or >450 (male), or history of congenital long 
QT syndrome. Any ECG abnormality that in the opinion of the Investigator would preclude safe 
participation in the study; patients with pacemakers where QTc is not a reliable measure will require 

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an evaluation by a cardiologist to exclude co-existing cardiac conditions which would prohibit safe 
participation in the study.  
21. Known to be human immunodeficiency virus (HIV) positive unless HIV ribonucleic acid (RNA) 
is undetected; known to have active hepatitis B (acute or chronic infection requiring antiviral 
treatment; hepatitis B surface antigen-positive) or have hepatitis C antibodies unless hepatitis C virus 
RNA is undetected/negative. 
22. Serious nonmalignant disease or other circumstance that could compromise protocol objectives in 
the opinion of the Investigator and/or the Sponsor. 
23. History of osteonecrosis of the hip or have evidence of structural bone abnormalities in the 
proximal femur on magnetic resonance imaging (MRI) scan that are symptomatic and clinically 
significant. Degenerative changes of the hip joint are not exclusionary. Screening of patients is not 
required. 
24. Known osteoblastic bony metastasis. Screening of patients without a history of metastatic bony 
lesions is not required. 
25. History of gastrointestinal perforation and/or fistulae within 6 months prior to first dose of study 
drug, clinically significant bleeding from the gastrointestinal tract within 1 month prior to first dose of 
study drug, or clinically significant bowel obstruction (CTCAE ≥Grade 2). 
26. Major surgery within 4 weeks of first dose of study drug. 
27. Serious psychiatric or medical conditions that could interfere with treatment. 
28. Toxicities (as a result of prior anticancer therapy) that have not recovered to baseline or stabilized, 
except for AEs not considered a likely safety risk (e.g., alopecia, neuropathy, and specific laboratory 
abnormalities). 
29. Administration of a live vaccine within 28 days before first dose of study drug. 
a. Note: Seasonal vaccines for influenza or COVID vaccines are generally inactivated 
vaccines and are allowed. Intranasal vaccines are live vaccines and are not allowed. 
30. Underlying medical conditions (including laboratory abnormalities) or alcohol or drug abuse or 
dependence that will be unfavorable for the administration of study drug, or affect the explanation of 
drug toxicity or AEs, or result in insufficient or impaired compliance with study conduct. 
31. Women who are pregnant or are breastfeeding. 
32. Concurrent participation in another therapeutic clinical study. 
a. Note: Concurrent participation in observational or non-interventional studies is allowed. 
In addition, patients who have completed active treatment in a clinical study and are in the 
follow-up period can be enrolled in this study. 
33. Treatment with radiation therapy within 14 days prior to first dose of study drug. 
Investigational Product, Dose, and Mode of Administration: 
Part A and B only: The duration for each cycle is 21 days and the study treatment regimens are as 
follows: 
Part 
DKN-01 
Tislelizumab 
Oxaliplatin 
Capecitabine 
Part A 
300 mg IV 
D1, 15 
200 mg IV 
D1 
130 mg/m2 IV D1  
1000 mg/m2 PO 
BID D1-D15 

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Part B1 
300 mg IV 
D1, 15 
200 mg IV 
D1 
- 
- 
Part B2 
600 mg IV 
D1, 15 
200 mg IV 
D1 
- 
- 
Abbreviations: BID = twice daily; D = Day; IV = intravenously; PO = orally. 
 
Part C only: The duration for each cycle is based on the chemotherapy regimen: CAPOX is 21 days 
and mFOLFOX6 is 14 days. The study regimens are as follows or per institutional standard practice: 
 
Chemo 
Regimen 
DKN-01 
Tislelizumab 
Oxaliplatin1 
Capecitabine1 
Leucovorin 
calcium1, 6 
Fluorouracil1 
Experimental Group 
CAPOX  
600 mg IV  
D12  
200 mg IV  
D1 q 3 weeks 
130 mg/m2 IV 
D1 
1000 mg/m2 PO 
BID; D1-D153 
- 
- 
mFOLFO
X6 
400 mg IV  
D14 
 
400 mg IV 
D1 q 6 weeks5 
85 mg/m2 IV 
D1 
- 
400 mg/m2 IV  
D1 
400 mg/m2 IV 
bolus on D1 
then 2400 
mg/m2 IV 
continuous 
infusion over 
48 hours D1 
and D2 
Control Group 
CAPOX 
- 
200 mg IV  
D1 q 3 weeks 
130 mg/m2 IV 
D1 
1000 mg/m2PO 
BID; D1-D153 
- 
- 
mFOLFO
X6 
- 
400 mg IV 
D1 q 6 weeks5 
85 mg/m2 IV 
D1 
- 
400 mg/m2 IV  
D1 
400 mg/m2 IV 
bolus on D1 
then 2400 
mg/m2 IV 
continuous 
infusion over 
48 hours D1 
and D2 
Abbreviations: BID = twice daily; D = day; IV = intravenously; PO = orally; q = every 
1 Standard dosing regimen per institutional standard of care. 
2 For Cycle 1 only, an additional loading dose of DKN-01 (600 mg, IV) will be administered on Day 15. 
3 A total of 28 doses from Day 1 through Day 15 
4 For Cycle 1 only, an additional loading dose of DKN-01 (400 mg, IV) will be administered on Day 8. 
5 Administered every 6 weeks starting on C1D1 and continuing every third 14-day cycle (e.g., C4D1, C7D1, etc.). 
6 If leucovorin is unavailable, 200 mg/m2 levo-leucovorin may be used. Study treatment may be administered without either agent if neither 
are available or that is per institutional standard of care. 
DKN-01: DKN-01 will be administered intravenously (IV) without interruption over a minimum of 
30 minutes and up to a maximum of 2 hours.  
Tislelizumab: Tislelizumab will be administered IV; the initial infusion (C1D1) will be delivered 
over 60 minutes; if this is well tolerated, then the subsequent infusions (CxD1) may be administered 
over 30 minutes, which is the shortest time period permissible for infusion. Tislelizumab must not be 
concurrently administered with any other drug. 
Oxaliplatin – Part A and C Only: Oxaliplatin will be administered IV according to institutional 
standard of care.  
Capecitabine – Part A and C Only: Capecitabine will be administered orally according to 
institutional standard of care.  

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Leucovorin calcium and Fluorouracil – Part C Only: Leucovorin calcium and fluorouracil will be 
administered IV according to institutional standard of care. 
Order of Administration 
In Part A, the order of IV administration will be DKN-01, tislelizumab, and then oxaliplatin. 
Capecitabine may be taken at any time on Day 1. 
In Part B, DKN-01 will be administered first, followed by tislelizumab. 
In Part C, the order of IV administration in the experimental group will be DKN-01, tislelizumab 
followed by chemotherapy regimen thereafter.  
• 
For patients receiving CAPOX, the order of IV administration will be DKN-01, 
tislelizumab, and then oxaliplatin. Capecitabine may be taken at any time on Day 1.  
• 
For patients receiving mFOLFOX6, the order of administration will be DKN-01, 
tislelizumab, followed by chemotherapy (oxaliplatin, leucovorin, and fluorouracil will be 
given per institutional SOC guidelines). 
In Part C, the order of IV administration in the control group will be tislelizumab followed by 
chemotherapy regimen thereafter.  
• 
For patients receiving CAPOX, the order of IV administration will be tislelizumab and 
then oxaliplatin. Capecitabine may be taken at any time on Day 1.  
• 
For patients receiving mFOLFOX6, the order of administration will be tislelizumab, 
followed by chemotherapy (oxaliplatin, leucovorin, and fluorouracil will be given per 
institutional SOC guidelines). 
Statistical Methods: 
Part A and Part B  
Sample Size Determination 
The sample size for Part A and B of this Phase 2 study is not based on formal statistical calculations as 
this is a pilot study designed primarily to seek information on the safety, efficacy, and 
pharmacokinetics/pharmacodynamics of DKN-01 in combination with tislelizumab ± CAPOX. Data 
collected from previous clinical studies indicates that DKN-01 is well tolerated. It was therefore 
determined that 20 patients would be sufficient to assess the safety and tolerability of DKN-01 in 
combination with tislelizumab ± CAPOX in a pilot study. 
A maximum of 24 patients (first-line treatment) will be enrolled in Part A to ensure 20 evaluable 
patients. A maximum of 48 patients (DKK1-high G/GEJ adenocarcinoma, second-line treatment) will 
be enrolled in Part B to ensure 40 evaluable patients. With a sample size of 20 evaluable patients in 
Part A, observed ORR rates of 69%, 77%, or 80% would be statistically greater than the 50% 
expected success rate at a 0.05 one-sided significance level with at least 50%, 80%, or 90% power, 
respectively. With a sample size of 40 evaluable patients in Part B, observed ORR rates of 42%, 49%, 
or 53% would be statistically greater than the ≥30% expected success rate at a 0.05 one-sided 
significance level with at least 50%, 80%, or 90% power, respectively.  
It is estimated that approximately 180 patients will be screened to achieve the target of 24 patients 
enrolled in Part A and 48 patients in Part B. 
Part C 
Statistical Hypothesis 
The primary efficacy endpoint is PFS, and the study is designed to test the superiority of DKN-01 plus 
tislelizumab and chemotherapy (CAPOX or mFOLFOX6), the experimental treatment, over 

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tislelizumab and chemotherapy (CAPOX or mFOLFOX6), the control treatment, for DKK1 high and 
in all patients. The primary analysis will test the following hypotheses: 
• 
Null Hypothesis: The hazard ratio for PFS between experimental and control treatment is 
equal to one. 
• 
Alternative Hypothesis: The hazard ratio for PFS between experimental and control 
treatment is less than one.  
Sample Size Determination 
The sample size for Part C of this Phase 2 study is estimated based on  the primary efficacy endpoint 
PFS as this part of the study is designed primarily to seek information on the efficacy of DKN-01 in 
combination with tislelizumab and chemotherapy regimen (CAPOX or mFOLFOX6) as compared to 
the combination of tislelizumab and chemotherapy regimen (CAPOX or mFOLFOX6) alone in 
DKK1-high patients and in patients regardless of their DKK1 status (all-comers). It is determined that 
a total of approximately 160 patients (approximately 80 patients in each treatment group) would be 
sufficient to assess the efficacy of DKN-01 in combination with tislelizumab and chemotherapy for 
DKK1-high patients and in patients regardless of their DKK1 status.  
With a power of 83% and a one-sided Type I error of 10%, a total of 137 PFS events of all-comer 
patients are required to detect a treatment effect hazard ratio of 0.681 (median PFS for all-comers is 
7.7 months in the control arm and 11.3 months in the experimental arm). With a power of 80% and a 
one-sided Type I error of 10%, a total of 49 PFS events of DKK1-high patients are required to detect a 
treatment effect hazard ratio of 0.546 (median PFS for DKK1-high patients is 6.5 months in the 
control arm and 11.9 months in the experimental arm) in DKK1-high patients. 
The sample size and power calculations are based on the following assumptions: Assuming a 
recruitment period of 12 months, a 10% probability of dropping out during the course of the study, a 
minimum follow-up of 24 months, and approximately 50% of patients will be DKK1-high. If the 
proportion of DKK1 high patients is not 50%, the power of PFS in DKK1-high patients will vary and 
may require further evaluation. 
 
 For purposes of analysis, the following populations are defined: 
 
Description 
Enrolled  
All patients who signed the main study informed consent form (ICF). 
Safety Population 
 
For Part A and B: All patients who signed the ICF and received at least 1 dose 
of DKN-01. This is the primary population for the Safety Analysis. 
For Part C: The safety population is defined as all patients who are randomized 
and receive at least one dose of study treatment. 
Efficacy  
Intent-to-Treat (ITT) 
Population 
For Part A and B: The intent-to-treat population (full analysis set) is defined to 
be all patients who enrolled and received at least one dose of DKN-01. 
For Part C: The intent-to-treat population is defined to be all patients 
randomized to treatment. Patients will be included in the treatment group 
assigned at randomization regardless of the actual treatment received. 
Modified Intent-to-Treat 
(mITT) Population  
For Part A and B: All patients who received more than one dose of DKN-01. 
This is the primary population for the efficacy analyses including PFS and OS.  
For Part C: All randomized patients who receive at least one cycle of study 
treatment.  

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Response Evaluable 
Population 
Part A: All patients who received any amount of DKN-01 + tislelizumab + 
oxaliplatin + capecitabine and have measurable baseline and at least 1 evaluable 
post-baseline RECIST tumor response assessment. 
Part B1 and B2: All patients who received any amount of DKN-01 + 
tislelizumab and have a measurable baseline and at least 1 evaluable post-
baseline RECIST tumor response assessment. 
Part C: All patients who received any amount of tislelizumab + chemotherapy 
regimen (CAPOX or mFOLFOX6) ± DKN-01 and have measurable baseline 
and at least 1 evaluable post-baseline RECIST tumor response assessment. 
Per-Protocol (PP) 
Population 
Part A and B: All enrolled patients without important protocol deviations that 
necessitates exclusion from this population or compliance issues, as applicable.  
Part C: All patients who are randomized and received the study treatment 
(tislelizumab + chemotherapy regimen [CAPOX or mFOLFOX6] ± DKN-01) 
as planned and have no important protocol deviations. The PP population will 
be used for sensitivity analyses of the primary and secondary objectives. 
Pharmacokinetics 
Population DKN-01 
All enrolled patients with available serum-time concentration data from patients 
dosed with DKN-01.  
Pharmacokinetics 
Population tislelizumab 
All enrolled patients with available serum-time concentration data from patients 
dosed with tislelizumab. 
Biomarker population 
There is one biomarker population for each of the following biomarkers: 
- DKK1 tumor expression in messenger RNA (mRNA) by chromogenic in situ 
hybridization (CISH). 
- Programmed cell death protein ligand-1 (PD-L1) expression by IHC. 
Abbreviations: DKK1 = Dickkopf-1; ICF = informed consent form; PD-L1 = programmed cell death protein ligand 1. 

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LIST OF ABBREVIATIONS AND TERMS 
Abbreviation 
Definition 
ADA 
anti-drug antibodies  
ADCC 
antibody-dependent cellular cytotoxicity 
ADCP 
antibody-dependent cellular phagocytosis 
ADL 
activities of daily living 
AE 
adverse event 
ALT 
alanine aminotransferase 
ANC 
absolute neutrophil count 
AST 
aspartate aminotransferase  
AUC0-∞ 
area under the drug concentration-time curve from time zero to infinity  
BID 
twice daily 
BSA 
body surface area 
C1D1 
Cycle 1, Day 1 (pattern set for cycle and days [e.g., C1D8, C2D1, etc.]) 
CAP 
College of American Pathologists 
CAPOX 
capecitabine + oxaliplatin 
CI 
confidence interval 
CISH 
chromogenic in situ hybridization 
CK 
creatine kinase 
CK-MB 
creatine kinase cardiac isoenzyme 
CL 
clearance 
CLIA 
Clinical Laboratory Improvement Amendments 
Cmax 
maximum observed serum concentration 
CNS 
central nervous system 
CR 
complete response 
CPS 
Combined positive score 
CT 
computed tomography 
CTCAE 
Common Terminology Criteria for Adverse Events 
ctDNA 
circulating tumor DNA 
D 
day 
DCB 
durable clinical benefit 
DCR 
disease control rate 
DKK1 
Dickkopf-1 
DoCB 
duration of clinical benefit 

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Abbreviation 
Definition 
DoCR 
duration of complete response 
DoR 
duration of response 
EBV 
Epstein Barr virus 
EC 
esophageal cancer 
ECG 
electrocardiogram 
ECOG 
Eastern Cooperative Oncology Group 
eCRF 
electronic case report form 
EDC 
electronic data capture 
eGFR 
estimated glomerular filtration rate 
EOT 
end of treatment 
FcRn 
neonatal Fc receptor 
FcγR 
gamma fragment crystallizable region receptor 
FDG-PET 
fludeoxyglucose-positron emission tomography 
GCP 
Good Clinical Practice 
G/GEJ 
gastric or gastroesophageal junction  
GI 
gastrointestinal 
HER2 
human epidermal growth factor receptor 2 
HIV 
human immunodeficiency virus 
ICI 
ICF 
Immune checkpoint inhibitor 
informed consent form 
ICH 
International Council for Harmonisation 
IHC 
immunohistochemistry 
IND 
Investigational new drug application 
INR 
international normalized ratio 
irAE 
immune-related adverse events 
IRB/IEC 
Institutional Review Board/Independent Ethics Committee 
iRECIST 
Immune-related Response Criteria in Solid Tumors 
ISH 
in situ hybridization 
IV 
intravenous(ly) 
IRT 
Interactive Response Technology 
Leap 
Leap Therapeutics, Inc. 
mAb 
monoclonal antibody 
mFOLFOX6 
leucovorin calcium, fluorouracil, and oxaliplatin 

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Abbreviation 
Definition 
MedDRA 
Medical Dictionary for Regulatory Activities 
MM 
multiple myeloma  
MMF 
mycophenolate mofetil 
MRI 
magnetic resonance imaging 
mRNA 
messenger ribonucleic acid 
MSI-H, MSI-L 
microsatellite instability-high, microsatellite instability-low 
MSS 
microsatellite stable 
NCI 
National Cancer Institute 
NE 
not evaluable 
NK 
natural killer 
NLR 
neutrophil-to-lymphocyte ratio 
NYHA 
New York Heart Association 
ORR 
objective response rate 
OS 
overall survival 
PD-1 
programmed cell death protein 1 
PD-L1 
programmed cell death protein ligand-1 
PET 
positron emission tomography 
PFS 
progression-free survival 
PI 
Principal Investigator 
PK 
pharmacokinetic 
PO 
orally 
PR 
partial response 
Q2W 
once every 2 weeks 
QW 
once weekly 
RECIST 
Response Evaluation Criteria in Solid Tumors 
RNA 
ribonucleic acid 
SAE 
serious adverse event 
SD 
stable disease 
SOC 
system organ class 
SOD 
SRT 
Sum of Diameters 
Safety Review Team 
TAP 
Tumor area positivity 
TEAE 
treatment-emergent adverse event 

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Abbreviation 
Definition 
TESAE 
treatment-emergent serious adverse event 
TMDD 
target-mediated drug disposition 
TPS 
tumor percentage score 
TSH 
thyroid-stimulating hormone 
ULN 
upper limit of normal 
V2, V3 
peripheral volume 
Vc 
central volume 
WBC 
white blood cells 
“X” L 
“X” Line of therapy 

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1. 
INTRODUCTION 
1.1. 
Background Information on Gastric and Gastroesophageal Junction 
Adenocarcinoma 
The combination of DKN-01 and tislelizumab is being investigated for the treatment of 
inoperable, locally advanced or metastatic gastric or gastroesophageal junction (G/GEJ) 
adenocarcinoma.  
Gastric adenocarcinoma remains one of the most common and deadly cancers worldwide, 
especially among older males in whom this cancer is more prevalent than women. Based on 
GLOBOCAN 2018 data, gastric adenocarcinoma is the fifth most common neoplasm and the 
third most deadly cancer, with an estimated 783,000 deaths in 2018, following only lung and 
colorectal cancer in overall mortality. About 1 in 12 or 1.8% of all oncological deaths are 
attributable to gastric adenocarcinoma. The cumulative risk of developing gastric 
adenocarcinoma from birth to age 74 is 1.87% in males and 0.79% in females worldwide (Bray, 
Ferlay et al. 2018, Rawla and Barsouk 2019).  
According to the National Cancer Institute, there were an estimated 113,054 people living with 
gastric adenocarcinoma in the United States of America (USA) in 2016. In 2020, it is estimated 
that there will be 27,600 new cases of gastric adenocarcinoma and an estimated 11,010 people 
will die of this disease. Gastric adenocarcinoma represents 1.6% of all new cancer cases in the 
United States (ACS 2020). Adenocarcinoma of the esophagus and GEJ or proximal 
esophagogastric junction is the fastest growing cancer in the Western population, especially in 
the USA, rising by 6-fold annually on the background of declining rates of most other cancers 
(Fenoglio-Preiser, Carneiro et al. 2000, Siewert, Marcus et al. 2000) and 2.5-fold compared 
with 1970 incidence of GEJ cancers. 
The prognosis of patients with gastric cancer may vary based upon the stage of cancer as well as 
factors such as nodal involvement and direct tumor extension beyond the gastric wall and tumor 
grade (Nakamura, Ueyama et al. 1992, Siewert, Böttcher et al. 1998, Adachi, Yasuda et al. 
2000). The 5-year survival rates for Tumor Node Metastasis stages IA and IB tumors treated 
with surgery are 94% and 88%, respectively (Zhang, Zhou et al. 2014, Wang, Sun et al. 2015). 
Overall 5-year survival is approximately 32%. Long remissions are rare in disseminated gastric 
cancer, and treatments are primarily palliative (NCI 2002).  
1.2. 
Current Treatment of G/GEJ Adenocarcinoma and Unmet Clinical 
Needs 
Management of G/GEJ adenocarcinoma is challenging, as these tumors involve 2 contiguous 
organs and also straddle the thoracic cavity and abdominal cavity via hiatal opening. 
Management of G/GEJ adenocarcinomas depends on the stage of the tumor. For early-stage 
tumors there is a role for endoscopic submucosal dissection, but advanced tumors require 
multimodality treatment including surgery, chemotherapies, and immunotherapies. 
1.2.1. 
Treatment Modalities 
Multimodality approach: The optimal multimodality approach is not well established, but 
relative benefits of preoperative chemoradiotherapy versus perioperative chemotherapy versus 

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initial surgery followed by postoperative chemoradiotherapy or chemotherapy have been 
debated (Ashraf, Hoffe et al. 2015, Lin, Khan et al. 2019, Petrelli, Ghidini et al. 2019, Wagner, 
Lordick et al. 2020). The approach most adopted clinically for G/GEJ adenocarcinoma includes 
a combined modality therapy rather than surgery alone and includes preoperative or 
neoadjuvant therapy for most patients with cT3 or higher, node-positive, or borderline 
resectable G/GEJ adenocarcinoma who will likely tolerate a combined modality 
treatment(Ashraf, Hoffe et al. 2015). This approach has been preferred over perioperative 
chemotherapy (Ashraf, Hoffe et al. 2015). Perioperative chemotherapy can be an alternative 
option for patients who are unable to tolerate trimodality therapy and when clinical suspicion 
for occult metastatic disease is high (Cunningham, Allum et al. 2006, Ychou, Boige et al. 2011, 
Ashraf, Hoffe et al. 2015).  
Several chemotherapy regimens have been studied, and options include epirubicin, cisplatin, 
and 5-fluorouracil (ECF) based on the MAGIC trial (Cunningham, Allum et al. 2006), 
epirubicin plus cisplatin and capecitabine (ECX) based on the MRC OE05 trial (Alderson, 
Cunningham et al. 2017), or infusional 5-fluorouracil plus cisplatin (Ychou, Boige et al. 2011); 
for younger and fit patients, docetaxel, oxaliplatin, leucovorin, and 5-fluorouracil may be an 
option based on results from the FLOT4-AIO trial (Al-Batran, Hofheinz et al. 2016). Generally, 
4 cycles of preoperative chemotherapy are preferred over 6 cycles when ECX or ECF is chosen.  
For concurrent chemoradiotherapy, although an optimal regimen is not well established, a 
doublet rather than single-agent chemotherapy is preferred, and options include 2 courses of 
cisplatin and 5-fluorouracil (CALGB 9781 trial; [(Tepper, Krasna et al. 2008)]) or low-dose 
weekly carboplatin plus paclitaxel per results from the Dutch CROSS trial (Shapiro, van 
Lanschot et al. 2015). The CROSS regimen is most frequently recommended and adopted for 
this modality of treatment. The optimal dose-fractionation radiotherapy for concurrent 
chemoradiotherapy is yet to be determined, since many earlier trials were performed before the 
availability of newer techniques like 3D conformal radiotherapy and intensity-modulated 
radiotherapy. Modern 3D conformal techniques are preferred to reduce toxicities to vital organs, 
and regardless of the specific chemotherapy regimen used, a standard dose of radiation for 
patients treated with concurrent chemotherapy is 50.4 Gy (Herskovic, Martz et al. 1992, Tepper, 
Krasna et al. 2008).  
Surgical treatment options: Surgical management is dictated by the anatomic location of the 
tumor. Patients with Siewert type I tumors are not candidates for a pure transabdominal 
approach, and the standard recommended approach is transthoracic en bloc esophagectomy and 
partial gastrectomy with 2-field lymphadenectomy. Most type II and type III tumors are offered 
total gastrectomy with a transabdominal/transhiatal resection of the distal esophagus with 
lymphadenectomy of lower mediastinum and abdominal D2 nodal compartment (Hulscher, van 
Sandick et al. 2002, Sasako, Sano et al. 2006, Omloo, Lagarde et al. 2007). Patients who are not 
surgical candidates can be treated with a definitive chemoradiotherapy approach, although it is 
less desirable as a curative option.  
For patients who have undergone surgery after preoperative chemotherapy alone, postoperative 
chemotherapy is preferred over chemoradiotherapy (Verheij, Jansen et al. 2016). Post-operative 
radiotherapy is reserved for patients with a histologically positive resection margin. The NCCN 
guidelines suggest postoperative fluoropyrimidine-based chemoradiotherapy for margin-

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positive resection and chemotherapy alone (if used preoperatively) for residual node-positive 
but margin-negative disease (Verheij, Jansen et al. 2016). 
For patients who undergo initial surgery without neoadjuvant therapy, postoperative adjuvant 
therapy is recommended for margin-positive disease, node-positive disease, or pathologic T3 or 
higher primary tumor stage (Macdonald, Smalley et al. 2001, Lee, Lee et al. 2012a). 
1.2.2. 
Current Treatment of Gastric and Gastroesophageal Junction Adenocarcinoma 
and Unmet Clinical Needs 
G/GEJ adenocarcinoma represents a major cause of cancer-related deaths (Bray 2018). 
Recently, several products have been approved globally for the treatment of this disease. The 
backbone of first-line (1L) systemic therapy includes a fluoropyrimidine and a platinum agent 
(standard of care) with addition of trastuzumab in human epidermal growth factor receptor 2 
(HER2) overexpressing patients (Rogers 2022). Recently the Checkmate-649 trial demonstrated 
the addition of the anti-PD1 antibody, nivolumab, to 1L standard of care therapy improved 
overall survival compared with SOC alone, in particular in patients whose tumor have higher 
programmed death ligand 1 (PD-L1) expression (combined positive score [CPS] ≥5) (Janjigian 
2021). After progression on 1L therapy, paclitaxel with or without the anti-VEGFR2 antibody 
ramucirumab is a global standard for second line (2L) therapy (Wilke 2014). Following the 
Keynote-059 trial (Fuchs 2018), the anti-PD-1 antibody pembrolizumab demonstrated benefit 
for third line (3L) patients with PD-L1 positive tumors defined by a combined positive score 
(CPS) of 1 or greater (CPS ≥1 [Fuchs 2018]). Pre-specified analysis from pembrolizumab-
containing trials, including Keynote-061 (2L) and Keynote-062 (1L), have identified subsets of 
patients more likely to benefit from immune-checkpoint inhibitors (ICI), including those with 
higher PD-L1 scores (CPS ≥10) and/or microsatellite instable (MSI-H) tumors (Chao 2021; 
Shitara 2020; Wainberg 2021). However, this represents the minority of patients, and intrinsic 
resistance to ICI remains a critical unmet need. Discriminatory biomarkers independent of PD-
L1 and MSI-H represent a key area of investigation with potential to identify patients more 
likely to respond to ICIs. 
Despite the availability of these products, an unmet medical need remains for treatment of 
patients with G/GEJ adenocarcinoma, a rare disease. None of the products approved to date for 
the treatment of gastroesophageal cancers specifically target patients with high Dickkopf-1 
(DKK1) expression, a target population for DKN-01. 
1.3. 
Background Information on the Study Drugs DKN-01 and 
Tislelizumab 
Please refer to the latest version of the DKN-01 Investigator’s Brochure or Tislelizumab 
Investigator’s Brochure (BeiGene) for the most current information available for DKN-01 and 
tislelizumab, respectively. 
1.3.1. 
Background Information DKN-01 
DKN-01 (formerly known as LY2812176) is a humanized monoclonal antibody (mAb) 
(immunoglobulin G4 [IgG4]) optimized for neutralizing activity against DKK1 protein. 
DKN-01 is in development as an anticancer agent and is being studied for treatment of several 
human malignancies, including G/GEJ adenocarcinoma. 

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1.3.1.1. 
Pharmacology of DKN-01 
DKN-01 is a potent mAb with neutralizing activity against DKK1, a secreted modulator of Wnt 
signaling, a multifaceted pathway that regulates stem cell maintenance, cell fate decisions, cell 
proliferation, survival, migration and polarity determination during development and adult 
tissue homeostasis (Logan and Nusse 2004, MacDonald, Tamai et al. 2009, Clevers and Nusse 
2012, Clevers, Loh et al. 2014, Sedgwick and D'Souza-Schorey 2016). DKN-01 is in 
development as an anticancer agent and is being investigated in a variety of solid tumors.  
Wnt signaling is a multifaceted pathway that regulates stem cell maintenance, cell fate 
decisions, cell proliferation, survival, migration, and polarity determination during development 
and adult tissue homeostasis (Logan and Nusse 2004, MacDonald, Tamai et al. 2009, Clevers 
and Nusse 2012, Clevers, Loh et al. 2014, Sedgwick and D'Souza-Schorey 2016). DKK1 is best 
characterized as an antagonist of the canonical Wnt/-catenin signaling pathway; however, it 
has also been implicated in the activation of noncanonical Wnt signaling pathways and 
PI3K/AKT signaling (Niehrs 2006, Wang and Zhang 2011, Kimura, Fumoto et al. 2016).  
The overexpression of DKK1 in tumors or elevated levels of DKK1 in patient serum has been 
associated with cancer-promoting activity in many types of cancer. Cancers with tumors that 
express DKK1 or induce elevated patient serum levels include breast, chondrosarcoma, 
cholangiocarcinoma, cervical, colorectal, endometrial, esophageal, gastric, glioblastoma, 
kidney, liver, laryngeal, lung, malignant fibrous histiocytoma, multiple myeloma, osteosarcoma, 
ovarian, pancreatic, prostate, and urothelial cancer (Kagey and He 2017). 
DKK1 has direct tumor effects by increasing tumor growth, metastasis, and angiogenesis and by 
favoring a stem cell-like phenotype(Smadja, d'Audigier et al. 2010, Thudi, Martin et al. 2011, 
Krause, Ryan et al. 2014, Malladi, Macalinao et al. 2016). Furthermore, DKK1 has been 
implicated in promoting an immunosuppressive tumor microenvironment by activating myeloid 
derived suppressor cells and through the downregulation of natural killer (NK) activating 
ligands on cancer cells (D'Amico, Mahajan et al. 2016, Malladi, Macalinao et al. 2016).  
Anti-DKK1 antibody inhibited the invasive activity and the growth of cancer cells in vitro and 
suppressed the growth of engrafted tumors in vivo in mice, while tumor tissues treated with 
anti-DKK1 displayed significant fibrotic changes and a decrease in viable cancer cells without 
apparent toxicity in mice (Sato, Yamabuki et al. 2010). 
Anti-DKK1 neutralizing antibodies have been hypothesized to not only directly impede tumor 
growth but also promote an antitumor immune response (Kagey and He 2017).  
1.3.1.2. 
Toxicology of DKN-01 
Repeat-dose studies have been conducted with DKN-01 in cynomolgus monkeys and 
Sprague-Dawley rats with doses up to 100 mg/kg administered once weekly for 8 weeks. No 
noteworthy findings were observed in the monkeys. In 2 studies conducted in Sprague-Dawley 
rats, histopathological examination revealed epiphyseal femoral head necrosis in control 
animals and animals that received DKN-01 at the 100 mg/kg dose. The incidence and severity 
of epiphyseal femoral head necrosis was higher in the male animals that received the 100 mg/kg 
dose than in control animals; therefore, it is possible that DKN-01 increased the incidence and 
severity of this finding.  

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Evaluation of embryofetal developmental effects induced by DKN-01 in rats and rabbits 
indicated no effects on embryo survival or toxicity; however, at the high dose of 100 mg/kg, 
malformations or increases in malformations from control levels were observed. Specifically, 
imperforation of the anal opening occurred in rats, and there was a minimal apparent increase in 
malformations relating to the vertebral column and ribs in rabbits in the 2 test-article-treated 
groups. These findings were present in a single control fetus with multiple malformations and 
were generally seen in the historical background data of the testing facility. Thus, due to the 
small group size, the etiology of this finding in relation to treatment cannot be conclusively 
determined. 
Studies in DKK1 knockout mice (Mukhopadhyay, Shtrom et al. 2001, Morvan, Boulukos et al. 
2006) suggest that blocking DKK1 with a mAb may pose a risk of teratogenesis.  
1.3.1.3. 
Clinical Pharmacology of DKN-01 
After single intravenous (IV) administration of DKN-01 to healthy volunteers at doses of 7 to 
300 mg, there was an overall trend for increasing half-life with increasing dose, ranging from 11 
to 19 days. As expected for IV administration, the increase in maximum observed serum 
concentration (Cmax) values were dose proportional while the area under the drug concentration-
time curve from time zero to infinity (AUC0-∞) values increased in a greater than dose 
proportional manner between 7 and 70 mg, suggesting nonlinear clearance, particularly within 
the 7 to 70 mg dose range. This non-linearity in PK is likely due to target-mediated drug 
disposition (TMDD). 
In patients with cancer, DKN-01 serum levels and exposure metrics (Cmax and the AUC from 
time 0 to the last measurable concentration) generally increased in slightly greater than dose 
proportional manner over a dose range of 75 to 300 mg. However, exposure between 300 to 
600 mg was approximately dose proportional. A dosing frequency of once weekly (QW) or 
once every 2 weeks (Q2W) both resulted in drug accumulation. The degree of accumulation 
observed was consistent with drug half-life, as well as the observation that drug levels did not 
appear to have reached steady state within 4 weeks of dose initiation.  
After dosing with DKN-01, a dose-dependent and time-dependent increase in mean total serum 
DKK1 levels was observed, consistent with TMDD. Modeling suggested that this increase was 
due to the target engagement by DKN-01 to form a DKN-01/DKK1 complex, which was 
cleared more slowly than free unbound DKK1. Concurrent with complex formation, free levels 
of DKK1 were modeled to have decreased. Thus, administration of DKN-01 led to a dose and 
time dependent suppression of free DKK1 concentrations in serum. 
Population pharmacokinetic (PK) analysis was conducted using data from 4 studies (Study 
DEK-DKK1-P100, DEK-DKK1-P101, DEK-DKK1-P102, and DEK-DKK1-P103) comprising 
163 patients. 
• Study DEK-DKK1-P100  
• Part A included 13 patients with multiple myeloma, advanced solid tumors, or 
refractory non–small cell lung cancer (NSCLC) who received DKN-01 doses of 
75 mg, 150 mg, and 300 mg weekly, and 600 mg every 2 weeks 

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• Part B included patients with refractory NSCLC who received a DKN-01 dose of 
300 mg every 2 weeks.  
• Study DEK-DKK1-P101 included patients with multiple myeloma (MM) who received 
a DKN-01 dose of 300 mg every 2 weeks.  
• Study DEK-DKK1-P102 comprised patients with relapsed or refractory esophageal 
cancer (EC) or GEJ tumors. 
• Part A – 150 mg every 2 weeks and 300 mg every 2 weeks (patients with 
relapsed or refractory EC or GEJ tumors) 
• Part B – 300 mg every 2 weeks (patients with relapsed or refractory EC or GEJ 
tumors 
• Part C – 300 mg every 2 weeks (patients with esophageal or GEJ 
adenocarcinoma  
• Part D – 300 mg every 2 weeks (patients with esophageal squamous cell cancer)  
• Part E – 300 mg every 2 weeks (patients with gastric adenocarcinoma with Wnt 
signaling alterations)  
• Patients with advanced or recurrent esophageal, GEJ, or gastric cancer who were 
not eligible to receive paclitaxel were enrolled as part of a DEK-DKK1-P102 
monotherapy sub-study (300 mg every 2 weeks). 
• Study DEK-DKK1-P103 comprised patients with advanced carcinoma primary to the 
intra- or extra-hepatic biliary system or gallbladder. 
• Part A – 150 mg and 300 mg DKN-01 on Day 1 and Day 8 of a 21-day cycle  
• Part B – Patients were treated at the maximum tolerated dose (MTD) of DKN-01 
(300 mg). All patients also received gemcitabine 1000 mg and cisplatin 25 mg.  
The patient population was predominantly white (~90%) and male (~60%), with an overall 
baseline median age of 62 years and an overall baseline median weight of 72 kg. 
One of the primary objectives of this analysis was to provide plausible DKN-01 PK profiles 
such that exposure (both Cmax and AUC) could be calculated at various time points for all 
studies despite the limited PK sampling. In addition, free DKK1 concentrations could also be 
inferred from the model, and these values were used elsewhere to explore a possible 
relationship with clinical efficacy. 
The DKN-01/DKK1 population data was best described using a 2-compartment target mediated 
disposition model with a quasi-equilibrium assumption. Patient characteristics influencing 
DKN-01/DKK1 PK/PD included serum albumin and height, which affected the DKN-01 
elimination rate (kel). Serum albumin was negatively correlated with the DKN-01 elimination 
rate, and this is frequently observed for other monoclonal antibodies. This relationship may be 
explained by the action of the neonatal Fc receptor (FcRn), which mediates albumin turnover 
but protects IgG antibodies from degradation. Lower albumin might reflect decreased efficiency 
of FcRn catabolic/recycling capability, which may correlate with faster elimination of DKN-01.  

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Covariates related to body mass composition are probably the most frequently identified and 
clinically relevant covariates in population PK analyses. This is not surprising, since PK 
parameters such as clearance and volume are often a function of body size. Body weight is often 
found to influence a number of general pop-PK model parameters. However, in this study 
height was found to positively correlate with both DKN-01 elimination (kel), as well as DKN-01 
central compartment volume estimates. Finally, a positive correlation was found between the 
rate of DKN-01/DKK1 complex internalization/elimination and concentrations of baseline 
DKK1. 
1.3.1.4. 
Prior Clinical Experience with DKN-01 
As of 30 December 2019, DKN-01 has been evaluated in 30 healthy subjects and 345 patients 
with cancer in 6 industry-sponsored clinical studies. All 30 healthy subjects received a single 
dose of DKN-01. Among the 345 patients with cancer treated with DKN-01, 111 received 
DKN-01 monotherapy; 7 received DKN-01 in combination with lenalidomide/dexamethasone; 
113 received DKN-01 in combination with paclitaxel; 51 patients received DKN-01 in 
combination with gemcitabine/cisplatin; and 63 received DKN-01 in combination with 
pembrolizumab. In addition, as controls in 2 clinical studies, 18 healthy subjects received a 
single dose of placebo and 1 patient with MM received lenalidomide/dexamethasone (Table 1). 
Refer to Section 1.6 for an overall benefit-risk assessment. 
Table 1: 
Individual Clinical Studies 
Protocol Number 
Study Title 
Study Status/ 
Number Subjects or 
Patients Dosed 
I3U-MC-GRCA 
A Placebo-controlled, Safety, Tolerability and 
Pharmacokinetic Parallel Group Study of Single 
Escalating Doses of LY2812176a, an Anti-DKK-1 
Humanized Antibody, in Subjects with Low Bone 
Mineral Density 
Complete 
DKN-01: 30 
Placebo: 18 
DEK-DKK1-P100 
A Two-Part, Phase 1, Multicenter, Open-Label, Study 
of DKN-01 Given Intravenously. Part A: A Dose-
Escalation Study in Patients with Multiple Myeloma 
or Advanced Solid Tumors. Part B: An Expansion 
Cohort in Patients with Relapsed or Refractory 
Non-Small Cell Lung Cancer (NSCLC) 
ClinicalTrials.gov Identifier: NCT01457417 
Complete 
DKN-01: 32 
DEK-DKK1-P101 
A Pilot Study of DKN-01 and Lenalidomide 
(Revlimid®)/ Dexamethasone versus 
Lenalidomide/Dexamethasone in Patients with 
Relapsed or Refractory Multiple Myeloma 
ClinicalTrials.gov Identifier: NCT01711671 
Completeb 
DKN-01+Len/Dex: 7 
Len/Dex: 1 

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Protocol Number 
Study Title 
Study Status/ 
Number Subjects or 
Patients Dosed 
DEK-DKK1-P102 
A Multi Part, Phase 1, Multi-center, Open-label Study 
of DKN-01 as a Monotherapy or in Combination with 
Paclitaxel or Pembrolizumab in Patients with 
Relapsed or Refractory Esophagogastric 
Malignanciesc ClinicalTrials.gov Identifier: 
NCT02013154 
Ongoing (N=151)F1 
DKN-01: 
Monotherapy: 291 
+Paclitaxel: 59 
+ Pembrolizumab: 63c 
DEK-DKK1-P103 
A Dose Escalation and Cohort Expansion Study of 
DKN-01 in Combination with Gemcitabine and 
Cisplatin in Patients with Advanced Carcinoma 
Primary to the Intra- or Extra-hepatic Biliary System 
or Gallbladder 
ClinicalTrials.gov Identifier: NCT02375880 
Complete 
DKN-01+Gem/Cis: 51 
DEK-DKK1-P204 
A Phase 2 Study Evaluating the Efficacy and Safety 
of DKN-01 as a Monotherapy or in Combination with 
Paclitaxel in Patients with Recurrent Epithelial 
Endometrial Cancer, Epithelial Ovarian Cancer, or 
Carcinosarcomad 
ClinicalTrials.gov Identifier: NCT03395080 
Ongoing 
DKN-01: 
Monotherapy: 51 
+Paclitaxel: 54 
Source: DKN-01 Investigator’s Brochure. 
a DKN-01 was previously named LY2812176. 
b Twenty patients were planned to be enrolled in Study DEK-DKK1-P101; however, the study was terminated after 8 patients 
were enrolled due to difficulty in meeting study enrollment target and changing treatment paradigms. Given that the study was 
terminated prematurely, only safety and PK data for this study are presented in this document; efficacy data are not presented. 
c Study P102 was amended on 21 July 2017 to include Study Part F, a combination arm of DKN-01 + pembrolizumab. 
d Study P204 was amended on 13 March 2019 to include a cohort of patients with recurrent carcinosarcoma (malignant mixed 
Mullerian tumor [MMMT]) to be treated with DKN-01 as monotherapy or DKN-01 + paclitaxel. 
1.3.1.4.1. Prior Clinical Experience in Gastroesophageal Cancer 
DKN-01 as a monotherapy or in combination with paclitaxel or pembrolizumab was assessed in 
patients with relapsed or refractory esophagogastric malignancies in a Phase 1, multicenter, 
open-label study (Study DEK-DKK1-P102). 
Study DEK-DKK1-P102 is a Phase 1 nonrandomized, dose-escalating, open label, multi-center 
study conducted in multiple parts (Parts A through F). In addition, a separate monotherapy sub-
study is being conducted concurrently with Parts B through F. A maximum of approximately 
224 patients aged 18 years or older with histologically confirmed recurrent or refractory 
esophageal, GEJ or gastric cancer with progressive disease requiring therapy are planned to be 
enrolled in the study. Expected enrollment in each study part was as follows: 
• Part A: Up to 12 patients in 2 cohorts of up to 6 patients per cohort 
• Parts B, D and E: Up to 20 patients in each part 
BeiGene 
1 
A total of 29 patients were enrolled into the monotherapy sub-study; however, 1 patient was deleted from the database due 
to an Informed Consent Form signature issue. The site’s Institutional Review Board was notified. 

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• Part C and Monotherapy Sub-study: Up to 40 patients in each part 
• Part F: A maximum of 12 patients (pembrolizumab-naïve and primary-refractory) in the 
dose-escalation phase. In the expansion phase, sufficient patients (approximately up to 
60) to ensure up to 55 evaluable patients at the target dose: up to 40 evaluable 
pembrolizumab-naïve patients in Group 1 and 15 pembrolizumab-primary refractory 
patients in Group 2. 
Thus, a maximum of approximately 184 patients with advanced refractory or recurrent 
esophageal, GEJ, or gastric cancer treated with at least one prior regimen with progressive 
disease requiring therapy were planned to be enrolled in the study and will receive DKN-01 in 
combination with paclitaxel or pembrolizumab. In addition, it is expected that up to 40 patients 
with advanced refractory or recurrent esophageal, GEJ, or gastric cancer who are unable to 
receive paclitaxel or pembrolizumab will be enrolled in the DKN-01 Monotherapy Sub-study. 
Total study enrollment across all study parts will be up to approximately 224 patients. 
A total of 150 patients were enrolled, including 28 patients who received DKN-01 
monotherapy; 59 patients who received DKN-01+ paclitaxel, 3 with DKN-01 150 mg and 56 
with DKN-01 300 mg; and 63 have received DKN-01+ pembrolizumab, 2 with DKN-01 150 
mg and 61 with DKN-01 300 mg. Data from Parts A through E and the Monotherapy Sub-study 
of this study are final as of 03 September 2019; as of this date, 5 patients from Part F were 
ongoing in the study rollover protocol. 
1.3.1.4.2. Safety Assessment 
1.3.1.4.2.1. 
DKN-01 Monotherapy in Gastroesophageal Cancer Patients (DEK-DKK1-
P102) 
Among patients treated with DKN-01 as monotherapy (N=28) in the Monotherapy Sub-study, 
the most common type of treatment-emergent adverse events (TEAEs) were gastrointestinal 
(GI) disorders (18 patients; 64%) and the most common individual TEAEs were fatigue 
(13 patients; 46%), anemia (9 patients; 32%), vomiting (8 patients; 29%), dehydration 
(7 patients; 25%), and nausea (6 patients; 21%).  
At least 1 TEAE was considered by the Investigator to be DKN-01-related for 16 (57%) 
patients, with the most common such events being fatigue (7 patients; 25%), anemia and 
vomiting (each 4 patients; 14%), and nausea and decreased appetite (each 3 patients; 11%). All 
other DKN-01-related TEAEs were reported for ≤2 patients.  
One (4%) patient treated with DKN-01 monotherapy experienced DKN-01-related Grade 3 
TEAEs, hyponatremia and lymphopenia. All other DKN-01-related TEAEs were Grade 1 or 2 
in intensity. 
No patient receiving DKN-01 as monotherapy discontinued study drug because of a TEAE. 
Among patients who received DKN-01 as monotherapy, 8 (29%) experienced at least 1 SAE, 
with infections and infestations being the most common type (3 patients; 11%). No individual 
SAE was reported for >1 patient. All SAEs reported among patients who received DKN-01 as 
monotherapy were considered by the Investigator to be unrelated to study drug. 

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One patient receiving DKN-01 monotherapy died due to a TEAE, sudden death, with this event 
considered unrelated to DKN-01. 
1.3.1.4.2.2. 
Combination Therapy with Paclitaxel in Gastroesophageal Cancer Patients 
(DEK-DKK1-P102) 
Among patients treated with DKN-01 300 mg + paclitaxel (N=56), the most common type of 
TEAEs were GI disorders (42 patients; 75%) and the most common individual TEAEs were 
fatigue (30 patients; 54%), anemia (26 patients; 46%), alopecia (19 patients; 34%), neutropenia 
and peripheral sensory neuropathy (each 32%), cough (16 patients; 29%), and dyspnea 
(14 patients; 25%). 
Among the 3 patients treated with the lower DKN-01 dose of 150 mg + paclitaxel, the TEAE 
profile was similar to that seen with the 300 mg dose, with the most common TEAEs being 
fatigue (3 patients; 100%) and arthralgia, headache, and toothache (each 2 patients; 67%). All 
other TEAEs were reported for 1 patient only at this dose level.  
Thirty-three (59%) of 56 patients treated with DKN-01 300 mg + paclitaxel experienced a 
DKN-01-related TEAE, most commonly fatigue (14 patients; 25%), diarrhea (7 patients; 13%), 
nausea, anemia, and decreased appetite (each 5 patients; 9%), and neutropenia (4 patients; 7%).  
Seven (13%) patients experienced a DKN-01-related ≥Grade 3 TEAE, including 
hypophosphatemia (2 patients; 4%) and anemia, leukopenia, monocytosis, neutropenia, and 
peripheral neuropathy (1 patient; 2%).  
DKN-01-related ≥Grade 3 TEAEs reported with DKN-01 150 mg + paclitaxel included single 
incidences of fatigue and peripheral sensory neuropathy. 
Overall, 2 patients receiving DKN-01 + paclitaxel discontinued DKN-01 due to a TEAE, 
including 1 patient receiving DKN-01 150 mg and 1 patient receiving DKN-01 300 mg. The 
TEAE leading to DKN-01 discontinuation was peripheral neuropathy/peripheral sensory 
neuropathy in both cases, with this event considered by the Investigator to be related to both 
DKN-01 and paclitaxel.  
Among the 56 patients who received DKN-01 300 mg + paclitaxel, 21 (38%) experienced at 
least 1 SAE, with infections and infestations being the most common type (9 patients; 16%). 
Individual SAEs reported for >1 patient included pneumonia (4 patients; 7%), and aspiration, 
lung infection, and pulmonary embolism (each 2 patients; 4%). All SAEs were considered by 
the Investigator to be unrelated to DKN-01. 
Six patients experienced a Grade 5 TEAE, including aspiration (2 patients) and 
cardiorespiratory arrest, monocytosis, pulmonary embolism, and respiratory failure (1 patient 
each). 
1.3.1.4.2.3. 
Combination Therapy with Pembrolizumab in Gastroesophageal Cancer 
Patients (DEK-DKK1-P102) 
Among patients treated with DKN-01 300 mg + pembrolizumab (N=61), the most common type 
of TEAEs were GI disorders (43 patients; 71%), with the most common individual TEAEs 
being fatigue (32 patients; 53%), anemia and blood alkaline phosphatase increased (each 

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21 patients; 34%), hyponatremia (19 patients; 31%), aspartate aminotransferase increased 
(18 patients; 30%), and decreased appetite (17 patients; 28%).  
Only 2 patients were treated with DKN-01 150 mg + pembrolizumab. Two patients intended to 
be treated with DKN-01 150 mg were inadvertently treated with 300 mg DKN-01 due to site 
error; neither patient experienced a TEAE. All TEAEs in this arm occurred in 1 patient only; no 
individual TEAE occurred in both patients in this treatment arm. 
Note that no treatment-related immune system disorders or infusion-related reactions, other than 
1 case of flushing, have been reported with DKN-01 in combination with pembrolizumab. 
Forty (66%) patients receiving DKN-01 300 mg + pembrolizumab experienced at least 1 TEAE 
considered by the Investigator to be at least possibly related to DKN-01. With the 300 mg dose, 
the most common DKN-01-related TEAEs were fatigue (11 patients; 18%), aspartate 
aminotransferase (AST) increased (9 patients; 15%), anemia (6 patients; 10%), alanine 
aminotransferase (ALT) increased and decreased appetite (each 5 patients; 8%), and nausea 
(4 patients; 7%).  
One (50%) patient receiving DKN-01 150 mg + pembrolizumab experienced TEAEs considered 
by the Investigator to be at least possibly related to DKN-01, dysphonia and flushing. 
Fifteen (25%) patients at the 300 mg dose level experienced a Grade 3 DKN-01-related TEAE. 
The only such events reported for >1 patient were anemia, AST increased, blood alkaline 
phosphatase increased, and hypophosphatemia (each 2 patients; 3%). 
Four (7%) patients receiving DKN-01 + pembrolizumab discontinued DKN-01 because of a 
TEAE, including Grade 2 pleural effusion in 1 patient; Grade 3 syncope and Grade 2 orthostatic 
hypotension in the setting of Grade 2 dehydration in a second patient; Grade 3 abdominal pain 
in a third patient; and Grade 3 pneumonia in a fourth patient. These events all were considered 
by the Investigator to be study drug-related.  
Among patients who received DKN-01 300 mg + pembrolizumab, 24 (39%) experienced at 
least 1 SAE, with metabolism and nutrition system disorders being the most common type 
(7 patients; 12%). The only SAE reported for >1 patient was abdominal pain (4 patients; 7%) 
and aspiration pneumonia, pneumonia, pulmonary embolism, and sepsis (each 2 patients; 3%). 
An SAE was considered by the Investigator to be DKN-01-related for 5 (8%) patients; 
DKN-01-related SAEs included abdominal pain, dehydration, hypophosphatemia, orthostatic 
hypotension, pleural effusion, pneumonia, and syncope (each 1 patient; 2%).  
Four patients experienced a Grade 5 (i.e., fatal) TEAE, including GI hemorrhage in 1 patient 
and disease progression in the remaining 3 patients; all of these events were considered by the 
Investigator to be unrelated to study drug. 
1.3.1.4.3. Efficacy 
Evidence of an antitumor effect of DKN-01 as monotherapy has been observed in patients with 
NSCLC, esophagogastric cancer, and gynecologic malignancies. Additionally, evidence of an 
antitumor effect has been observed with DKN-01 in combination with other anti-neoplastic 
agents in patients with gastroesophageal cancer, biliary tract cancer, and gynecologic 
malignancies. In particular, DKN-01 has demonstrated durable clinical benefit when used in 
combination with paclitaxel as a second-line therapy for gastroesophageal cancer.  

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Further, a study of DKN-01 in combination with pembrolizumab in patients with advanced 
G/GEJ adenocarcinoma identified a subgroup of patients with DKK1-high tumors with the 
greatest clinical benefit. 
To be evaluable for response according to the Response Evaluation Criteria in Solid Tumors 
(RECIST), version 1.1, patients enrolled in DEK-DKK1-P102 were required to have received at 
least 1 dose of DKN-01 and have at least 1 evaluable tumor response assessment or have 
discontinued treatment due to death, toxicity, or clinical progression. As of 30 December 2019, 
140 patients treated with DKN-01 300 mg were evaluable for response, including 27 treated 
with DKN-01 as monotherapy, 54 treated with DKN-01 + paclitaxel, and 59 treated with 
DKN-01 + pembrolizumab. In addition, 5 patients treated with DKN-01 150 mg, 3 in 
combination with paclitaxel, and 2 in combination with pembrolizumab, were evaluable for 
response. 
1.3.1.4.3.1. 
Monotherapy in Gastroesophageal Cancer Patients (DEK-DKK1-P102) 
Overall, in Study DEK-DKK1-P102, among the 28 patients who received the DKN-01 
monotherapy, 24 were male and 4 were female, and all 28 patients were white. The mean age of 
patients was 63 years (range 39 to 81 years). Patients were required to have advanced or 
recurrent gastroesophageal cancer to be eligible for the study; 21 had a primary diagnosis of 
esophageal cancer, 6 patients had a primary diagnosis of GEJ cancer, and 1 had a primary 
diagnosis of gastric cancer. The histological type was adenocarcinoma for 23 patients and 
squamous cell carcinoma for 5 patients. At the time of diagnosis, 17 patients had Stage IV 
disease, with 9 having Stage III disease, and 2 having Stage II disease. The median time since 
diagnosis was 17.9 months (range 6.0 to 46.3 months). All 28 patients received prior 
chemotherapy, with the median number of prior systemic therapy regimens being 3 (range 1 to 
7). Overall, 22 (79%) patients had received a prior taxane, 9 (32%) patients had received prior 
Herceptin (trastuzumab), and 3 (11%) had received a PD-1/PD-L1 inhibitor. 
No patient treated with DKN-01 as monotherapy experienced a complete response (CR) or 
partial response (PR) by Investigator assessment. However, 8 patients had a best response of 
stable disease (SD), making the disease control rate (DCR) 40% (8 of 20 evaluable patients).  
Among all patients in the full analysis set (FAS), median progression-free survival (PFS) was 
8.1 weeks (95% confidence interval [CI] 6.3, 11.4), and median overall survival (OS) was 
18.7 weeks (95% CI 8.7, 31.0). 
Overall, among the 27 patients treated with DKN-01 300 mg as monotherapy who were 
evaluable for response, the overall sum of target lesions at baseline was 83.0 mm. Although 
most patients experienced percent increases from baseline in the sum of target lesion 
measurements, mean percent decreases were seen, with 1 patient with esophageal cancer 
experiencing a maximum mean percent decrease from baseline in the sum of target lesion 
measurements of 27%; this degree change was seen after 4 cycles of therapy (Figure 1). 

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Figure 1: 
Spider Plot of Percent Change in Target Lesion Measurements, Based on 
RECIST v1.1, Among Patients Treated with DKN-01 Monotherapy, by 
Tumor Type (Evaluable Patients) 
 
 
Per protocol, tumor response in this study was to be based on the Investigator’s assessment. 
However, tumor response was assessed centrally, with the central assessment used for 
supportive analyses. Based on central review, of the 20 patients dosed only with DKN-01 across 
all malignancy types, 2 out of 20 (10%) had a best individual time point response of PR, 6 out 
of 20 (30%) had best individual time point response of SD, and 12 out of 20 (60%) had PD. 
There were no patients with CR (Figure 2, Figure 3).  

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Figure 2: 
Sum of Diameters Percent Change from Baseline – Monotherapy (Central 
Review) 
 
Abbreviations: SOD = sum of the diameters. 

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Figure 3: 
Best Percent Change in Sum of Diameters – Monotherapy (Central Review) 
 
Abbreviations: EAC = esophageal adenocarcinoma; ESCC= esophageal squamous cell carcinoma; GEJ AC = 
gastroesophageal adenocarcinoma; GC = gastric cancer.  
1.3.1.4.3.2. 
Combination Therapy with Paclitaxel in Gastroesophageal Cancer Patients 
(DEK-DKK1-P102) 
Overall, in Study DEK-DKK1-P102, among all 56 patients who received the DKN-01 target 
dose (300 mg) + paclitaxel, 43 were male and 13 were female, and 48 patients were white. The 
mean age of patients was 61 years (range 34 to 82 years). Patients were required to have 
gastroesophageal cancer to be eligible for the study; 29 patients had a primary diagnosis of GEJ 
cancer and 25 had a primary diagnosis of esophageal cancer; the 2 remaining patients had a 
diagnosis of gastric cancer. At the time of diagnosis, 30 patients had Stage IV disease, with 18 
having Stage III disease, and 8 having Stage II disease. The median time since diagnosis was 
15.6 months (range 2.1 to 70.4 months). All 56 patients received prior chemotherapy, with 
27 (48.2%) having received a prior taxane, 14 each in the adjuvant/neo-adjuvant setting and 
metastatic/palliative setting. (Patients may have received such treatment in more than 1 setting.) 
The median number of prior systemic therapy regimens was 2 (range 1 to 6). Overall, 11 (20%) 
patients had received prior Herceptin (trastuzumab) and 5 (9%) had received a PD-1/PD-L1 
inhibitor. 
Three patients received DKN-01 150 mg + paclitaxel, of whom all 3 were white males. The 
median age was 56 years, with a range of 47 to 73 years. Two patients had a primary diagnosis 
of GEJ cancer and 1 had a primary diagnosis of esophageal cancer. The median number of prior 
therapies was 4, and all 3 patients had received a prior taxane. 
A summary of efficacy results among treated with DKN-01+paclitaxel in Study P102, by dose 
and overall, is presented in Table 2. 

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Table 2: 
Summary of Efficacy Results in Patients Treated with DKN-01+Paclitaxel in 
Study DEK-DKK1-P102, Overall and by Dose 
Endpoint/Statistic 
DKN-01  
150 mg 
+ Paclitaxel 
DKN-01 
300 mg 
+ Paclitaxel 
Esophageala 
DKN-01 
300 mg 
+ Paclitaxel 
GEJ/Gastric 
DKN-01 
300 mg 
+ Paclitaxel 
Evaluable Populationb, n/N (%) 
 
 
 
 
Objective Response Rate 
1/3 (33.3) 
4/23 (17.4) 
7/26 (26.9) 
12/49 (24.5) 
Disease Control Rate 
3/3 (100) 
13/23 (56.5) 
15/26 (57.7) 
28/49 (57.1) 
PFS  
 
 
 
 
N 
3 
25 
30 
55 
Median, (95% CI) (Weeks) 
18.6 (13.4, 20.1)  
11.6 (7.9, 14.7) 
11.9 (8.0, 22.6) 
11.9 (8.0, 15.7) 
OS 
 
 
 
 
N 
3 
25 
30 
55 
Median (95% CI) (Weeks) 
34.4 (26.3, 89.7) 
28.4 (14.7, 33.3) 
27.9 (19.0, 39.0) 
28.4 (22.6, 33.3) 
Source: DKN-01 Investigator’s Brochure. 
Abbreviations: CI = confidence interval; GEJ = gastroesophageal junction; N = total number of patients treated; n = 
number of patients within each category; OS = overall survival; PFS = progression-free survival. 
a Evaluable population excludes 2 non-evaluable patients (non-measurable disease at baseline) and 4 patients 
without post-baseline assessments (no post-baseline imaging complete). 
b Patients with non-measurable disease at baseline were excluded from PFS analysis. 
DKN-01 + Paclitaxel 
In the evaluable population, among patients treated with DKN-01 300 mg + paclitaxel, the 
objective response rate (ORR) was 24.5% (12/49 patients) and the DCR was 57.1% (28/49).  
Among those with G/GEJ cancer treated with DKN-01 300 mg + paclitaxel evaluable for 
response (N=26), the ORR was 26.9% (7/26), and the DCR was 57.7% (15/26). 
The central imaging review reported of the 52 pooled combination therapy patients who 
received DKN-01 300 mg plus paclitaxel, 9 out of 52 (17.3%) had a best individual time point 
response of PR, 18 out of 52 (37.5%) had a best individual time point response of SD, and 24 
out of 52 (46.1%) had PD. There was a single non-CR/non-PD and there were no patients with 
CR. 
Among patients in the FAS who received DKN-01 300 mg + paclitaxel, median PFS was 
11.9 weeks (95% CI, 8.0, 15.7). Among those with G/GEJ cancer, median PFS was 11.9 weeks 
(95% CI 8.0, 22.6).  
Among patients in the FAS who received DKN-01 300 mg + paclitaxel, median OS was 
28.4 weeks (95% CI, 22.6, 33.3). Among those with G/GEJ cancer, median PFS was 
27.9 weeks (95% CI 19.0, 39.0).  
1.3.1.4.3.3. 
Combination Therapy with Pembrolizumab in Gastroesophageal Cancer 
Patients (DEK-DKK1-P102) 
Part F in Study P102, in which patients receive DKN-01 + pembrolizumab, is ongoing; thus, 
data are preliminary, based on a database lock on 03 September 2019.  

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Among 61 patients at the target dose of DKN-01 (300 mg), 55 patients were male and 6 were 
female. Age ranged from 28 to 81 years. Thirty-two (53%) patients in the target dose group had 
a primary diagnosis of GEJ cancer, with 22 having esophageal cancer and 7 having gastric 
cancer. Forty-six patients (75%) had Stage IV disease at diagnosis. The median time since 
diagnosis was 15 months (range 3 to 68 months). All patients had an Eastern Cooperative 
Oncology Group (ECOG) performance status of 0 or 1 at baseline.  
Although the numbers of patients in each group were disparate, demographic and baseline 
disease characteristics among patients with PD-1/PD-L1-naïve and refractory disease (i.e., naïve 
and refractory groups, respectively) were generally comparable, although, as would be 
expected, the median time since diagnosis was longer among refractory patients than naïve 
patients (24.0 months versus 11.8 months, respectively). Similarly, the mean number of prior 
systemic therapies was higher in the refractory group than in the naïve group (3.6 versus 1.9, 
respectively). In accordance with the entry criteria, all patients in the refractory group had 
received prior anti-PD-1/PD-L1 therapy.  
A summary of efficacy results in patients treated with DKN-01+pembrolizumab is presented in 
Table 3. 
Table 3: 
Summary of Efficacy Results Among Patients Treated with 
DKN-01+Pembrolizumab 
150 mg 
DKN-01 
+ Pembro 
300 mg 
DKN-01 
+ Pembro 
anti-PD-1/ 
PD-L1 
Naïve ESO 
300 mg 
DKN-01 
+ Pembro 
anti-PD-1/ 
PD-L1 
Naïve 
GEJ/GC 
All 300 mg 
DKN-01 
+ Pembro 
anti-PD-1/ 
PD-L1 
Naïve 
300 mg 
DKN-01 
+ Pembro 
Primary 
Refractory 
to 
Anti-PD-
1/PD-L1 
All 
300 mg 
DKN-01 
+ Pembro 
Efficacy Evaluable Population 
Objective Disease Responsea 
0/2 
0/17 
5/27 (18.5) 5/44 (11.4) 
0/9 
5/53 (9.4) 
 95% CIb 
(0.0, 84.2) 
(0.0, 19.5) 
(6.3, 38.1) 
(3.8, 24.6) 
(0.0, 33.6) 
(3.1, 20.7) 
Objective Disease Controlc 
1/2 (50.0) 
4/17 (23.5) 13/27 (48.1) 17/44 (38.6) 4/9 (44.4) 
21/53 (39.6) 
 95% CIb 
(1.3, 98.7) 
(6.8, 49.9) 
(28.7, 68.1) (24.4, 54.5) (13.7, 78.8) (26.5, 54.0) 
Source: DKN-01 Investigator’s Brochure. 
Abbreviations: CI = confidence interval; ESO = esophageal; GC= gastric cancer; GEJ = gastroesophageal junction; 
PD-1 = programmed cell death-1; PD-L1 = programmed cell death ligand-1. 
a Disease response is the number of patients with a best overall response of CR or PR. Does not require 
confirmation of response. Denominator only includes patients who are eligible for response evaluation per RECIST 
v1.1 post baseline. 
b 95% confidence interval (CI) is calculated based on the exact Clopper-Pearson for binomial proportions. 
c Disease control is the number of patients with a best overall response of CR, PR, or SD. Does not require 
confirmation of response or any minimum SD duration. Denominator only includes patients who are eligible for 
evaluation.  
Anti-PD-1/PD-L1 Naïve Patients 
Among evaluable patients at the target dose (300 mg), the ORR was 11.4% (5/44) (95% 
confidence interval [CI] 3.8, 24.6) and the DCR was 38.6% (17/44) (95% CI 24.4, 54.5) in the 
naïve target dose group. 

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Among evaluable patients with G/GEJ adenocarcinoma, the ORR and DCR were 18.5% (5/26) 
(95% CI 6.3, 38.1) and 48.1% (4/26) (95% CI 28.7, 68.1), respectively, in the naïve target dose 
group.  
Central imaging results are not yet available for patients who received DKN-01 + 
pembrolizumab. 
Overall, median PFS was 6.0 weeks (95% CI 5.7, 8.7) in the naïve target dose group, and was 
6.9 weeks (95% CI 5.7, 12.0) in those with G/GEJ adenocarcinoma.  
Overall, median OS was 20.4 weeks (95% CI 14.4, 31.6) in the naïve target dose group, and 
was 22.1 weeks (95% CI 14.4, 42.4) in those with G/GEJ adenocarcinoma.  
In the 150 mg group, 1 patient was PD-1/PD-L1-naïve; this patient achieved a best response of 
SD. 
Anti-PD-1/PD-L1-Refractory Patients 
Among evaluable patients at the target dose (300 mg), the ORR was 0% (0/9) (95% CI 0, 33.6) 
and the DCR was 44% (4/9) (95% CI 13.7, 78.8) in the refractory target dose group.  
Among evaluable patients with G/GEJ adenocarcinoma, the ORR and DCR were 0% (0/5) 
(95% CI 0, 52.2) and 40.0% (2/5) (95% CI 5.3, 85.3), respectively, in the refractory target dose 
group.  
Overall, median PFS was 6.6 weeks (95% CI 3.0, 12.1) in the refractory target dose groups, and 
was 6.0 weeks (95% CI 3.0, 13.4) in those with G/GEJ adenocarcinoma.  
Median OS was 19.0 weeks (95% CI 10.7, 37.4) the refractory target dose group.  
In the 150 mg group, 1 patient was PD-1/PD-L1-refactory; this patient achieved a best response 
of SD. 
1.3.2. 
Background Information on Tislelizumab 
Tislelizumab, also known as BGB-A317 (BeiGene), is a humanized, IgG4-variant monoclonal 
antibody against PD-1 under clinical development for the treatment of several human 
malignancies, including locally advanced unresectable or metastatic G/GEJ 
adenocarcinoma(Xu, Arkenau et al. 2019). 
1.3.2.1. 
Pharmacology of Tislelizumab 
Tislelizumab acts by binding to the extracellular domain of human PD-1 with high specificity as 
well as high affinity 
 It competitively blocks binding efforts 
by both PD-L1 and programmed cell death protein ligand-2 (PD-L2), thus inhibiting 
PD-1-mediated negative signaling in T cells. In in vitro cell-based assays, tislelizumab was 
observed to consistently and dose-dependently enhance the functional activity of human T cells 
and pre-activated, primary peripheral blood mononuclear cells. Tislelizumab has demonstrated 
in vivo antitumor activity in several allogeneic xenograft models, in which peripheral blood 
mononuclear cells were co-injected with human cancer cells (A431 [epidermoid carcinoma]) or 
tumor fragments (BCCO-028 [colon cancer]) into immunocompromised mice.  
Tislelizumab is an IgG4-variant antibody 
 
 

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 In vitro assays with tislelizumab suggest either low 
or no antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular 
phagocytosis (ADCP), or complement-dependent cytotoxicity (CDC) effects in humans 
(Labrijn, Buijsse et al. 2009, Zhang, Song et al. 2018). Tislelizumab was specifically engineered 
to abrogate these potential mechanisms of T-cell clearance and potential resistance to anti-PD-1 
therapy. 
Please refer to the Tislelizumab Investigator’s Brochure (BeiGene) for additional details 
regarding nonclinical studies of tislelizumab. 
1.3.2.2. 
Toxicology of Tislelizumab 
The toxicity and safety profile of tislelizumab was characterized in single-dose toxicology 
studies in mice and cynomolgus monkeys and in a 13-week, repeat-dose toxicology study in 
cynomolgus monkeys. Tissue cross-reactivity was evaluated in normal frozen tissues from both 
humans and monkeys. The cytokine release assays were conducted using fresh human whole 
blood cells. The pivotal toxicology studies were conducted following Good Laboratory Practice 
regulations. The single-dosing regimens spanned from the intended human doses to 10-fold 
higher than the maximum of the intended human doses, and the repeat-dosing regimens spanned 
to 3-fold higher than the maximum of the intended human doses. Cynomolgus monkey was the 
only relevant species based on the target sequence homology and binding activity. 
Overall, no apparent toxicity was noted in mice or monkey toxicity studies. No tissue 
cross-reactivity was found in either human or monkey tissues, nor was any effect on cytokine 
release observed in the human whole-blood assay. The toxicokinetic profile was well 
characterized, with dose proportional increases in systemic exposure without apparent 
accumulation or sex difference. Immunogenicity was observed without apparent 
immunotoxicity or effect on the systemic exposure. The no observed adverse effect level of 
tislelizumab in the 13-week monkey toxicity study was considered to be 30 mg/kg. The safety 
profile of tislelizumab is considered adequate to support the current study, DEK-DKK1-P205. 
Please refer to the Tislelizumab Investigator’s Brochure (BeiGene) for more detailed 
information on the toxicology of tislelizumab. 
1.3.2.3. 
Clinical Pharmacology of Tislelizumab 
Population PK analysis was conducted using data from 798 patients with solid tumors or 
classical Hodgkin lymphoma who received doses of 0.5, 2.0, 5.0, and 10 mg/kg once every 
2 weeks, 2.0 and 5.0 mg/kg once every 3 weeks, and 200 mg once every 3 weeks. The PK of 
tislelizumab was best characterized using a 3-compartmental linear population PK model with 
linear clearance mechanisms. No time-varying clearance was observed in tislelizumab PK. The 
typical estimates of clearance (CL), central volume (Vc), and peripheral volumes (V2, V3), were 
0.164 L/day, 2.92 L, 0.928 L, and 1.39 L, respectively, with moderate inter-individual 
variability in CL (32.2%), Vc (16.7%), V2 (56.6%), and V3 (94.2%). The volume of distribution 
at steady state was 5.238 L, which is typical of monoclonal antibodies with limited distribution, 
which is consistent with a standard immunoglobulin G (IgG) monoclonal antibody (Dirks and 
Meibohm 2010, Keizer, Huitema et al. 2010, Deng, Jin et al. 2012, Ryman and Meibohm 2017). 
Based on the population PK analysis, tislelizumab PK was characterized by a terminal half-life 

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of approximately 25.5 days, which is consistent with other therapeutic IgG monoclonal 
antibodies. 
Population PK analysis demonstrated that baseline age, race/ethnic origin, alanine 
aminotransferase, aspartate aminotransferase, bilirubin, lactate dehydrogenase, estimated 
glomerular filtration rate, ECOG performance status, immunogenicity, and sum of products of 
perpendicular diameters in classical Hodgkin lymphoma patients did not show statistically 
significant impact on the PK of tislelizumab. Although tumor size, albumin, and tumor type 
were significant covariates on CL, while body weight, sex, and tumor type were significant 
covariates on Vc, these covariates are not expected to have a clinically relevant impact on 
tislelizumab exposure. Exposure-response analysis indicated that there was a lack of clinically 
significant exposure-response relationships for ORR and safety endpoints across a variety of 
advanced solid tumors and classical Hodgkin lymphoma for tislelizumab. Population PK 
analysis supports fixed-dosing across different ethnic groups. 
1.3.2.4. 
Prior Clinical Experience with Tislelizumab 
As of 20 May 2019, there were 22 ongoing studies with tislelizumab with over 1705 patients 
treated. Of these, 13 studies have preliminary data available in the Tislelizumab Investigator’s 
Brochure version 7, 13 September 2019: 7 monotherapy studies, 2 chemotherapy combination 
therapy studies; and 4 investigational agent combination therapy studies. 
Refer to the Tislelizumab Investigator’s Brochure (BeiGene) for more detailed information on 
tislelizumab safety and efficacy data when given as monotherapy or in combination with 
chemotherapy. 
1.3.2.4.1. Pooled Safety Assessment of Monotherapy Studies 
A pooled analysis of 7 monotherapy studies was conducted to provide a comprehensive safety 
assessment separately from combination therapy. 
Overall, there were 1273 patients in the pooled monotherapy studies: 1137 patients treated in 
5 solid tumor studies and 136 patients treated in 2 hematologic malignancies studies. 
Solid tumor studies included the following: BGB-A317_Study_001 (Phase 1a /1b Advanced 
Solid Tumors), BGB-A317-102 (Phase 1 /2 Advanced Solid Tumors), BGB-A317-204 (Phase 2 
Locally Advanced or Metastatic Urothelial Bladder Cancer), BGB-A317-208 (Phase 2 Locally 
Advanced or Metastatic Urothelial Bladder Cancer), and BGB-A317-209 (Previously Treated 
Locally Advanced Unresectable or Metastatic Microsatellite Instability-High (MSI-H) or 
Mismatch Repair Deficient (dMMR) Solid Tumors). The 2 studies in hematologic malignancies 
are BGB-A317-203 (Phase 2 Relapsed or Refractory Classical Hodgkin Lymphoma) and BGB-
A317-207 (Relapsed or Refractory Mature T- and NK-cell Neoplasms). 
Of the 1273 total patients treated, 544 patients (42.7%) remained on study as of 20 May 2019; 
and 272 patients (21.4%) were still receiving tislelizumab treatment. 
Refer to the Tislelizumab Investigator's Brochure (BeiGene) for more detailed information on 
tislelizumab safety data when given as monotherapy or in combination with chemotherapy. 

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1.3.2.4.1.1.Pooled Demographics and Baseline Characteristics 
Table 4 shows the demographics and baseline characteristics for the patients treated in the 
pooled monotherapy studies. 
Table 4: 
Demographics, Baseline Characteristics, Treatment Exposure Duration, and 
Study Follow-up Duration in Pooled Monotherapy Studies 
Measure 
Overalla 
N = 1273 
Age (years) 
 
  Median 
59.0 
  Min, Max 
18, 90 
Sex, n (%) 
 
  Male 
852 (66.9) 
  Female 
421 (33.1) 
Race/Ethnic Origin, n (%) 
 
  Asian 
807 (63.4) 
  Black 
11 (0.9) 
  White 
405 (31.8) 
  Missing 
2 (0.2) 
  Other 
48 (3.8) 
Prior systemic anticancer therapy regimensb 
 
  Median 
1.0 
  Min, Max 
0, 12 
Prior systemic anticancer therapy regimens (grouped)b, n (%) 
  0 
271 (21.3) 
  1 
413 (32.4) 
  2 
265 (20.8) 
  ≥3 
324 (25.5) 
Study treatment exposure duration (months) 
 
  Median 
3.58 
  Min, Max 
0.1, 43.6 
Study follow-up duration (months) 
 
  Median 
8.34 
  Min, Max 
0.1, 47.5 
Source: Tislelizumab Investigator’s Brochure. 

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Abbreviations: Max = maximum; Min = minimum; N = total number of patients treated; n = number of patients 
within each category. 
Data cutoff 20 May 2019. 
a Solid Tumor Studies include: BGB_Study_001, BGB-A317-102, BGB-A317-204, BGB-A317-208, BGB-A317-
209 and Hematology Studies include: BGB-A317-203, BGB-A317-207.b Only systemic therapies were selected. 
Overall, the 1273 patients in the pooled monotherapy analysis had a median treatment exposure 
duration of 3.58 months (range 0.1 to 43.6) and median study follow-up duration of 8.34 
months (range 0.1 to 47.5). Overall, the total pooled monotherapy population had a median age 
of 59 years and was 66.9% male. 
1.3.2.4.1.2.Treatment-Emergent Adverse Events Assessed as Related to Treatment 
Of the 1273 total patients treated in the pooled monotherapy studies, 846 (66.5%) experienced 
at least one treatment-related TEAE. The most commonly occurring TEAEs (≥5% of patients) 
assessed as related to tislelizumab were increased aspartate aminotransferase (128 patients, 
10.1%), increased alanine aminotransferase (123 patients, 9.7%), hypothyroidism (113 patients, 
8.9%), rash (96 patients, 7.5%), and pyrexia (94 patients, 7.4%). 
Of the 1273 total patients treated in the pooled monotherapy studies, 162 (12.7%) experienced 
at least one ≥Grade 3 TEAE assessed as related to tislelizumab. The ≥Grade 3 TEAEs that 
occurred in ≥1% (≥12 patients) in the total study population were increased aspartate 
aminotransferase (19 patients, 1.5%) and increased alanine aminotransferase (15 patients, 
1.2%). 
1.3.2.4.1.3.Treatment-Emergent Serious Adverse Events 
Of the 1273 total patients treated in the pooled monotherapy studies, 424 (33.3%) experienced 
at least one treatment-emergent serious adverse event (SAE). The most commonly occurring 
treatment-emergent SAEs were pneumonia (35 patients, 2.7%), pyrexia (22 patients, 1.7%), and 
ascites (17 patients, 1.3%). 
1.3.2.4.1.4.Immune-Related Adverse Events  
Anti-PD-1 therapies are known to cause immune-related adverse events (irAEs) in some 
patients. Therefore, irAEs have been defined as AEs of special interest in tislelizumab clinical 
studies and as such are being reported expeditiously and closely monitored. 
Immune-related AEs are consistent with an immune-related mechanism or immune-related 
component for which non-inflammatory etiologies (e.g., infection or tumor progression) have 
been ruled out. Immune-related AEs can include events with an alternate etiology which were 
exacerbated by the induction of autoimmunity. There is a potential temporal relationship 
between the initiation of treatment with tislelizumab and onset of an irAE that spans a window 
of days to several months. 
All irAEs presented here are assessed as related to study drug by the Investigator and 
categorized by the BeiGene Safety/Pharmacovigilance team. Certain irAEs have multiple 
MedDRA terms associated with the same category. Special categories have been created to 
group patients experiencing these events. 
All irAEs that have occurred in ≥1% in the total pooled monotherapy studies are shown in 
Table 5. 

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Table 5: 
Immune-Related Adverse Events of Any Grade Occurring in ≥1% in Pooled 
Monotherapy Studies 
Categories 
  Preferred Term 
Total 
(N = 1273) 
Any Grade 
n (%)a 
Grade ≥3 
n (%)a 
Patients with at least one potential immune-
related AEa 
602 (47.3) 
121 (9.5) 
Immune-related skin adverse reaction 
242 (19.0) 
11 (0.9) 
Rash 
97 (7.6) 
4 (0.3) 
Pruritus 
78 (6.1) 
0 
Pruritus generalised 
29 (2.3) 
0 
Rash maculo-papular 
24 (1.9) 
1 (0.1) 
Immune-related hepatitis 
233 (18.3) 
51 (4.0) 
Aspartate aminotransferase increased 
129 (10.1) 
21 (1.6) 
Alanine aminotransferase increased 
124 (9.7) 
16 (1.3) 
Blood bilirubin increased 
74 (5.8) 
4 (0.3) 
Gamma-glutamyltransferase increased 
45 (3.5) 
17 (1.3) 
Bilirubin conjugated increased 
40 (3.1) 
3 (0.2) 
Immune-related endocrinopathies 
187 (14.7) 
7 (0.5) 
Hypothyroidism 
113 (8.9) 
0 
Hyperthyroidism 
47 (3.7) 
1 (0.1) 
Hyperglycaemia 
17 (1.3) 
4 (0.3) 
Immune-related colitis 
75 (5.9) 
10 (0.8) 
Diarrhoea 
66 (5.2) 
5 (0.4) 
Immune-related pneumonitis 
50 (3.9) 
30 (2.4) 
Pneumonitis 
22 (1.7) 
9 (0.7) 
Lung infection 
13 (1.0) 
8 (0.6) 
Immune-related 
myositis/rhabdomyolysis/cardiomyopathy 
39 (3.1) 
7 (0.5) 
Blood creatine phosphokinase increased 
30 (2.4) 
4 (0.3) 
Immune-related nephritis and renal 
dysfunction 
33 (2.6) 
6 (0.5) 
Blood creatinine increased 
25 (2.0) 
2 (0.2) 
Source: Tislelizumab Investigator’s Brochure. 

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Abbreviations: AE = adverse event; N = total number of patients treated; n = number of patients within each 
category; NCI-CTCAE = National Cancer Institute Common Terminology Criteria for Adverse Events; PT = 
preferred term; SOC = system organ class. 
Note: All AEs are coded using Medical Dictionary for Regulatory Activities and graded according to NCI-CTCAE 
v4.03. Maximum CTCAE grade was selected per patient under each PT. Potential immune-related AE is identified 
based on a predefined list of AEs and assessed as treatment-related by Investigators. 
Sorted in descending order of the number of patients in SOC and PT in Any Grade under Total column. 
Data cutoff 20 May 2019. 
a Percentages are based on the total population. 
Of the 1273 total patients for the pooled monotherapy studies, 602 (47.3%) experienced at least 
one irAE of any grade. The most commonly occurring irAEs of any grade were aspartate 
aminotransferase increased (129 patients, 10.1%), alanine aminotransferase increased 
(124 patients, 9.7%), hypothyroidism (113 patients, 8.9%), rash (97 patients, 7.6%), and 
pruritus (78 patients, 6.1%). Analysis of the total patients with at least one irAE that also was 
≥Grade 3 in severity showed that 121 patients (9.5%) experienced such events. The most 
commonly occurring irAEs ≥Grade 3 in severity were aspartate aminotransferase increased 
(21 patients, 1.6%), gamma-glutamyltransferase increased (17 patients, 1.3%), alanine 
aminotransferase increased (16 patients, 1.3%), pneumonitis (9 patients, 0.7%), and lung 
infection (8 patients, 0.6%). 
1.3.2.4.1.5.Infusion-Related Reactions 
Infusion-related reactions, including high-grade hypersensitivity reactions, following 
administration of tislelizumab are common. Of the 1273 total patients in the pooled 
monotherapy studies, 97 (7.6%) experienced at least one infusion-related reaction of any grade. 
The most commonly occurring infusion-related reactions of any grade that occurred in the total 
pooled analysis were pyrexia (50 patients, 3.9%), infusion-related reactions (28 patients, 2.2%), 
and pruritus (11 patients, 0.9%). There were 6 patients who reported a total of 7 ≥Grade 3 
infusion-related reactions in the pooled monotherapy studies (reported events included back 
pain, hypotension, infusion-related reaction, musculoskeletal chest pain, pyrexia, and rash). 
1.3.2.4.1.6.Fatal Adverse Events 
A summary of the treatment-emergent fatal AEs that occurred in the pooled monotherapy 
studies are shown in Table 6. 

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Table 6: 
Treatment-Emergent Fatal Adverse Events Regardless of Causality in 
Pooled Monotherapy Studies 
Category 
Overall 
(N = 1273) 
n (%) 
All deaths at data cutoff 
641 (50.4) 
Death ≤30 days after last dose 
105 (8.2) 
Primary cause of death 
 
 Adverse event 
21 (1.6) 
 Disease under study 
22 (1.7) 
 Progressive disease 
52 (4.1) 
 Other 
10 (0.8) 
Death >30 days after last dose 
536 (42.1) 
Primary cause of death 
 
 Adverse event 
14 (1.1) 
 Disease under study 
95 (7.5) 
 Indeterminate 
3 (0.2) 
 Progressive disease 
399 (31.3) 
 Other 
24 (1.9) 
 Missing 
1 (0.1) 
Source: Tislelizumab Investigator’s Brochure. 
Abbreviations: N = total number of patients treated; n = number of patients within each category. 
Data cutoff 20 May 2019. 
 
Table 6 shows a total of 105 patients (8.2% of the total population) died ≤30 days after the last 
study drug dose in the pooled monotherapy studies as of 20 May 2019. Of these 105 patients, 
there were 21 patients (1.6% of the total population) who had an AE with a fatal outcome 
≤30 days after the last study drug dose. Of the 536 patients (42.1% of the total population) who 
died >30 days after the last study drug dose, 14 patients (1.1% of the total population) died as a 
result of an AE (refer to the Tislelizumab Investigator’s Brochure (BeiGene). 
1.3.2.4.1.7.Tislelizumab Safety Summary  
For monotherapy, the safety profile of tislelizumab is similar across tumor types. There is no 
pattern in the incidence, severity, or causality of AEs to tislelizumab dose level. The safety 
profile for single-agent tislelizumab is similar to those observed in other PD-1 inhibitors. For 
combination studies, the safety profile of tislelizumab is generally consistent with use as a 
single agent and appears to be safe and well tolerated when used in combination with other 
agents and in multiple different chemotherapy backbones. 
1.3.2.4.2. Efficacy Assessment of Tislelizumab 
Two phase 2 studies are ongoing in patients with G/GEJ adenocarcinoma. 

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1.3.2.4.2.1.Study BGB-A317-205  
Study BGB-A317-205 is a multi-cohort, Phase 2 study of tislelizumab in combination with 
standard chemotherapy as first-line treatment in Chinese patients. An esophageal squamous cell 
carcinoma cohort and a GAC/GEJ adenocarcinoma cohort have been enrolled concurrently. The 
primary objective of this study is to evaluate the safety and tolerability of tislelizumab in 
combination with standard chemotherapy. Secondary objectives include the preliminary 
antitumor efficacy of this combination in this population. Additionally, PK and immunogenicity 
are being assessed. 
As of 20 May 2019, the median treatment exposure duration for patients in Study BGB-A317-
205 was 6.58 months (range 0.7 to 18.9), and the median study follow-up duration was 
13.47 months (range 0.1 to 19.2). 
The Efficacy Evaluable Analysis Set includes all the GAC/GEJ patients who have received at 
least 1 cycle of the combination therapy, had measurable or evaluable disease at baseline 
according to RECIST v1.1, and had at least 1 post baseline tumor response assessment unless 
any clinical progressive disease or death occurred within 10 weeks after the first dose. A 
summary of tumor response in the efficacy evaluable set is presented in Table 7. 

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Table 7: 
Summary of Tumor Response in Study BGB-A317-205 (Efficacy Evaluable 
Analysis Set) 
Category 
GAC/GEJ 
N=13 
ORR (CR, PR) 
n (%) 
7 (53.8) 
(Clopper-Pearson 95% CI) 
(25.13, 
80.78) 
Best Overall Response - Confirmed, n (%) 
Complete response 
0 
Partial response 
7 (53.8) 
Stable disease 
3 (23.1) 
Progressive disease 
1 (7.7) 
Non-Complete response /Non-Progressive diseasea 
2 (15.4) 
DCR (CR, PR, SD, Non-CR/Non-PD) 
n (%) 
12 (92.3) 
(Clopper-Pearson 95% CI) 
(63.97, 
99.81) 
CBR (CR, PR, durable SD, durable Non-CR/Non-PD) b 
n (%) 
9 (69.2) 
(Clopper-Pearson 95% CI) 
(38.57, 
90.91) 
Abbreviations: CBR = Clinical Benefit Rate; CI = confidence interval; CR = complete response; DCR = disease control rate; 
GAC/GEJ = gastric and gastroesophageal junction adenocarcinoma; NE = Not Evaluable; OR = Objective Response; ORR = 
objective response rate; PD = progressive disease; PR = partial response; RECIST = Response Evaluation Criteria in Solid 
Tumors; SD = stable disease. 
a 2 patients have only non-target lesions at baseline. 
b Durable SD or Non-CR/Non-PD: stable disease or Non-CR/Non-PD ≥24 weeks. 
OR is based on the confirmed CR or PR according to RECIST v1.1. Patients with no postbaseline response assessment or 
assessments as NE were considered as non-responders. 
The Efficacy Evaluable Analysis Set includes all patients who have received at least 1 dose of the study drug, had measurable or 
evaluable disease at baseline according to RECIST v1.1, and had at least 1 postbaseline tumor response assessment unless any 
clinical PD or death occurred within 10 weeks after the first dose. 
Data cutoff 20 May 2019. 
1.3.2.4.2.2.Study BGB-A317-305  
Study BGB-A317-305 is an ongoing randomized, double-blind, placebo-controlled, Phase 3 
clinical study comparing the efficacy and safety of tislelizumab plus platinum and 
fluoropyrimidine versus placebo plus platinum and fluoropyrimidine as first-line treatment in 
patients with locally advanced unresectable or metastatic G/GEJ adenocarcinoma. Results are 
not yet available. 

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1.4. 
Study Rationale  
1.4.1. 
Rationale for DKN-01 in the Treatment of Gastric and Gastroesophageal 
Junction Adenocarcinoma 
DKN-01 compound is a humanized IgG4 monoclonal antibody targeted against DKK1. DKK1 
is a protein that regulates Wnt signaling pathways. Aberrant Wnt signaling is often implicated 
in cancer, enabling cancer cells to grow and divide and to suppress the immune system. 
Published data indicates that DKK1 is often overexpressed in many cancers and is associated 
with worse outcomes, more aggressive tumor growth, and suppression of immune antitumor 
responses. 
A role for DKK1 in maintaining an environment around a tumor that suppresses the immune 
system's ability to clear the tumor and to prevent metastasis. DKK1 activates the suppressive 
effects of myeloid-derived suppressor cells, a type of white blood cell that can potently block 
the ability of other immune cells to attack a tumor. Additional data has shown that metastatic 
tumor cells with stem cell-like features avoid eradication by the immune system through 
overexpression of DKK1. DKK1 down-regulates NK cell activating ligands on tumor cells 
allowing them to remain invisible and evade the immune system. Furthermore, neutralization of 
DKK1 in preclinical tumor models depends on a functioning immune system and more 
specifically, NK cells. Through these multiple activities DKK1 helps protect the cancer cells 
from being targeted by the immune system. Therefore, blocking DKK1 activity has been 
proposed to stimulate an immune mediated antitumor response. Inhibition of DKK1 has 
demonstrated antitumor activity in preclinical models. Our hypothesis is that inhibiting DKK1 
can generate both a direct antitumor effect, as well as generate an immune antitumor response. 
Our preclinical and clinical data suggest that a DKK1 neutralizing antibody, DKN-01, is able to 
effectively synergize with certain chemotherapeutics and checkpoint inhibitors in their 
antitumor efficacy. 
Published studies have also demonstrated a correlation between a worse clinical prognosis for 
gastric cancer patients with high tumor DKK1 (protein) and/or serum levels (Liu, Li et al. 
2016). Furthermore, analysis of DKK1 messenger ribonucleic acid (mRNA) expression from 
tumors of patients with G/GEJ cancer indicates a worse overall survival for patients with high 
DKK1 levels (TCGA database – STAD dataset, data on file with the Sponsor). Taken together, 
these results indicate that DKK1 is a marker for poor prognosis in G/GEJ adenocarcinoma and 
may identify patients most likely to benefit from a DKK1 neutralizing therapy (Liu, Li et al. 
2016). 
Previous clinical experience in patients with advanced anti-PD-1/PD-L1 naïve G/GEJ 
adenocarcinoma in a Phase 1b/2a study of DKN-01 in combination with pembrolizumab 
demonstrated clinical benefit in patients with elevated tumor DKK1 mRNA expression as 
assessed retrospectively by an in situ hybridization (ISH) assay (Klempner, Bendell et al. 2020). 
Tumor DKK1 expression data was available for 31 G/GEJ adenocarcinoma patients and patients 
within the top tertile (H-scoreF2 ≥35) were considered DKK1 high. In patients with an evaluable 
response, the ORR was 50% for the DKK1-high (upper tertile) patients and 0% for the 
BeiGene 
2 H-score (range 0 to 300) was calculated by determining the percentage of cells that were low (1-3 dots), medium 
(4-9 dots) or high (10=<dots) DKK1 expressors and using the following formula: H-score = 
1*(%low)+2*(%medium)+3*(%high) 

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DKK1-low (bottom and middle tertiles) patients. Furthermore, patients with DKK1-high tumor 
expression experienced longer progression free (22.1 versus 5.9 weeks) and overall survival 
(31.6 versus 17.4 weeks) compared with DKK1 low patients, and this effect was independent of 
PD-L1 CPS. These data support a rationale for treating G/GEJ patients with high DKK1 tumor 
expression with a DKN-01 anti-PD-1 (tislelizumab) combination. 
1.4.2. 
Rationale for Tislelizumab in the Treatment of Gastric and Gastroesophageal 
Junction Adenocarcinoma 
Increases in PD-1 expression in tumor-infiltrating lymphocytes (TILs) and PD-1 ligand 
expression in tumor cells were reported in gastric cancer (Wu, Zhu et al. 2006). Recent clinical 
trials utilizing anti-PD-1 monoclonal antibodies demonstrated significant therapeutic efficacy 
in, for example, advanced melanoma, refractory NSCLC, and renal cell carcinoma. Anti-PD-1 
antibody treatment not only induced higher ORRs but also resulted in a lasting effect on overall 
survival (Ribas, Puzanov et al. 2015, Weber, D'Angelo et al. 2015). In addition, anti-PD-1 
antibodies were also reported to be efficacious in numerous cancer types, including but not 
limited to, NSCLC, SCLC, RCC, Hodgkin lymphoma, head and neck squamous cell carcinoma, 
HCC, microsatellite instability-high or mismatch repair deficient metastatic colorectal cancer, 
and urothelial carcinoma. 
High levels of FcγR-expressing myeloid derived suppressor cells (e.g., M2 macrophage, 
myeloid-derived suppressor cells) in tumor tissues predict poor survival of tumor-bearing 
animals.  
However, anti-PD-1 monoclonal antibody treatment may result in Fc-FcγR-mediated ADCC or 
ADCP depletion of effector T cells (Dahan, Sega et al. 2015, Gul and van Egmond 2015, 
Makarova-Rusher, Medina-Echeverz et al. 2015, Prieto, Melero et al. 2015, Beers, Glennie et 
al. 2016). As a no- to low-FcγR-binding agent (which causes minimal ADCC/ADCP effects), 
tislelizumab may show improved efficacy and reduced toxicity in gastric cancer.  
The anti-PD-1 monoclonal antibody tislelizumab has shown antitumor activity in patients with 
G/GEJ adenocarcinoma in 2 early-phase studies. A report of 207 patients in the Phase 1b 
portion of a Phase 1a/1b study of single-agent tislelizumab 5 mg/kg every 21 days included 54 
patients with gastric cancer (50 with adenocarcinoma) and 54 patients with esophageal cancer 
(26 with adenocarcinoma)(Deva, Lee et al. 2018). The ORR for gastric cancer patients was 
13.0%, with a DCR of 29.6%. The ORR for esophageal cancer patients was 11.1%, with a DCR 
of 37.0%. PD-L1 expression was assessed retroactively; ORRs were higher in both cohorts for 
patients whose cancers were PD-L1-positive versus those whose cancers were PD-L1-negative 
(gastric cancer 22.7% vs 4.3%; esophageal cancer 12.1% vs 5.9%). Treatment-related SAEs 
were reported in 10 of the 207 patients in the 4 cohorts in this report (4.8%); treatment-related 
SAEs included pneumonitis in 3 patients and acute hepatitis, dermatitis, diarrhea, increased 
ALT, increased AST, infusion-related reaction, pyrexia, and vomiting in 1 patient each. Two 
treatment-related fatalities (acute hepatitis in a patient with HCC and pneumonitis in a patient 
with NSCLC) had disease-related conditions cited as contributing factors. Results from 
15 patients with G/GEJ in a Phase 2b study indicate antitumor activity of the combination of 
tislelizumab 200 mg and oxaliplatin 130 mg/m2 on Day 1, and capecitabine 1000 mg/m2 BID on 
Days 1 through 15 of a 21-day cycle (Bai, Xu et al. 2019). The ORR among these 15 patients 
was 46.7% with a DCR of 80%. Responses were durable, with a median PFS of 6.1 months. 

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Serious adverse events (any cause) occurred in 5 G/GEJ patients (33.3%); all 5 experienced 
SAEs considered related to both tislelizumab and chemotherapy (Deva, Lee et al. 2018, Bai, Xu 
et al. 2019). 
1.4.3. 
Rationale for the Combination of DKN-01 and Tislelizumab in the Treatment 
of Gastric and Gastroesophageal Junction Adenocarcinoma 
Metastatic tumor cells with stem cell-like features are able to avoid eradication by the immune 
system through overexpression of DKK1, a protein that regulates Wnt signaling pathways and 
promotes tumor growth and metastasis (Kagey and He 2017). Blocking DKK1 activity has been 
proposed to stimulate an immune-mediated antitumor response. DKN-01 is a potent humanized 
monoclonal antibody with neutralizing activity against DKK1. 
Preclinical and clinical data suggest that DKN-01 may effectively synergize with checkpoint 
inhibitors such as tislelizumab and certain chemotherapeutics in causing tumor cell death and 
boosting the immune response against the tumor. 
The ability of mDKN-01 to have additive activity with an anti-PD-1 antibody was assessed in a 
B16 syngeneic model (Figure 4). Female B6 mice were inoculated subcutaneously with B16 
mouse melanoma cells on Day 0. The following day, twice-weekly treatment with an isotype 
control (10 mg/kg), mDKN-01 (10 mg/kg), anti-PD-1 antibody (12 mg/kg), or a combination of 
mDKN-01/anti-PD-1 was initiated. mDKN-01 and anti-PD-1 monotherapy resulted in TGIs of 
32% (p=0.01) and 45% (p=0.004), respectively at Day 14. The combination therapy resulted in 
a TGI of 70% (p<0.001) at Day 14, indicating that additive efficacy was observed.  

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Figure 4: 
In Vivo Antitumor Activity of Murine Surrogate DKN-01 is Additive with 
an Anti-PD-1 Antibody 
 
Abbreviations: MTV = mean tumor volume; PD-1 = programmed cell death protein 1; SEM = standard error of the 
mean; TGI = tumor growth inhibition. 
Female B6 (C57BL/6J) mice (15 per group) were inoculated subcutaneously in the right flank with 1x105 B16F0 
mouse melanoma cells on Day 0. The following day, twice-weekly intraperitoneally treatment of a IgG2a control 
(10 mg/kg), a murine surrogate IgG2a DKN-01 (mDKN-01) antibody with a D265A mutation to reduce effector 
function (10 mg/kg), anti-PD-1 (12 mg/kg), or a combination treatment of mDKN-01/anti-PD-1 was initiated. 
Tumors were measured every 3-4 days. Mean tumor volumes are plotted. Error bars represent SEM. Percent TGI = 
[(MTV Control) – (MTV Treated)]/(MTV Control). P-values were calculated using an unpaired T-test.  
The use of immunotherapy in the treatment of advanced, solid tumors has recently expanded 
with the development of monoclonal antibodies that boost the immune response against cancer 
cells by targeting checkpoint proteins on immune cells, such as PD-1, PD-L2, or cytotoxic 
T-lymphocyte-associated protein (Gong, Chehrazi-Raffle et al. 2018). Studies in the treatment 
of esophageal, GEJ and gastric cancers have been conducted with various immunotherapy 
agents, including tislelizumab, a humanized, IgG4-variant monoclonal antibody against PD-1 
(Zayac and Almhanna 2019).  
Recent clinical data show improved clinical outcomes in advanced G/GEJ cancer patients with 
DKK1-high tumors when treated with DKN-01 and anti-PD-1 therapy (pembrolizumab).  
1.5. 
Justification for Dose 
1.5.1. 
Rationale for DKN-01 Dose in Parts A and B 
DKN-01 will be administered at a dose of 300 mg (Part A and B1) or 600 mg (Part B2) IV on 
days (D) 1 and 15 in combination with tislelizumab, ± oxaliplatin and capecitabine in 21-day 
cycles, as described in Section 3.1.1.2.  
As discussed in Section 1.3.1.1, DKN-01 pharmacology has been associated with a number of 
direct and indirect effects on tumor growth, metastasis, and angiogenesis. It is thought that the 
antitumor effects of DKK1 are mediated in large part by binding to and neutralizing DKK1. In 
order to relate DKK1 neutralization to clinical efficacy, a pharmacokinetic/pharmacodynamic 
model was developed which could predict both the serum concentrations of DKN-01 and also 
the resulting free DKK1 serum concentrations (unbound). Higher concentrations of free or 

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unbound DKK1 equate to a lower degree of neutralization and vice versa. Model simulations 
were performed which assumed a Q2W dosing schedule and focused on the maximal 
concentration of free DKK1 achieved (Cmax) over the dosing interval. As noted, the objective of 
DKN-01 treatment was to reduce free DKK1 Cmax. A mean initial patient baseline value for free 
DKK1 (before treatment) was found to be approximately 5.4 ng/mL. With this value in mind, 
the model simulations in Figure 5 and Figure 6 demonstrate that the DKK1 Cmax was 
substantially reduced (relative to baseline) by a single administration of DKN-01 and continued 
to decrease over repeat doses. In Figure 5, free DKK1 could be decreased in the majority of 
patients (>95%), to a maximal value of 1.5 ng/mL after the first 300 mg dose. In addition, after 
repeat 300 mg Q2W dosing, the highest free DKK1 Cmax levels declined to approximately 
0.8 ng/mL (or less) for 95% of patients. Additional simulations showed that when the DKN-01 
dose was increased to 600 mg, the highest free DKK1 Cmax was decreased to approximately 
0.8 ng/mL after the first dose, and then to 0.4 ng/mL after repeat Q2W dosing to steady state. 
Several ongoing clinical studies have been conducted to determine the effect of DKN-01 on a 
variety of cancers. In Study DEK-DKK1-P102 (P102; NCT02013154), DKN-01 was dosed in 
combination with paclitaxel as well as in a separate monotherapy study. In this study, patients 
were administered DKN-01 at doses of 150 or 300 mg Q2W over a 28-day cycle (Study Parts 
A-E, and monotherapy). Study Part F was a 21-day cycle. Patients in Study DEK-DKK1-P103 
(P103; NCT02375880) were administered DKN-01 at doses of 150 or 300 mg in combination 
with gemcitabine and cisplatin on Days 1 and 8 of a 21-day cycle. Note that between these 
2 studies only the dosing schedule for Q2W P102 was comparable to the initial simulations 
above. However, in both of these clinical studies modeling fits to DKN-01/DKK1 concentration 
data showed a dose dependent decrease in free DKK1 Cmax concentrations. For example, in 
Study P102, the median free DKK1 Cmax after the last administered 300 mg DKN-01 dose was 
0.52 ng/mL (range 0.14-8.5 ng/mL). This value was comparable to the simulations discussed 
above and aids in understanding the importance of adequate drug levels to neutralize free 
DKK1. 
In the P102 study, the relationship between drug levels and PD, SD, and PR patients was 
examined after a 300 mg dose. Figure 7 plots the individual patient drug trough levels (over a 
Q2W dosing interval) with PD, SD, or PR. This figure plots results from Part F of Study P102, 
which had the greatest number of patients with a similar dose of DKN-01, comedication, and 
cancer type. In Part F there were 63 patients, 33 with PD, 17 showing SD, 5 with a PR, and 8 
with no evaluation. In this figure it can be seen that efficacy was associated with a trend of 
higher drug levels. In summary, the modeling performed supports the idea that higher doses of 
DKN-01 lead to greater DKK1 neutralization, and higher drug levels which was associated with 
efficacy. The proposed 300 mg dose is supported by positive results observed in P102, and by 
extension, a 600 mg dose would lead to higher drug levels, greater free DKK1 suppression and 
potentially greater efficacy. 

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Figure 5: 
Predicted Maximal Free Serum DKK1 (Cmax) Concentrations after 300 mg 
DKN-01 IV Dosing Administered Once Every Two Weeks (Q2W) 
 
Figure 6: 
Predicted Maximal Free Serum DKK1 (Cmax) Concentrations after 600 mg 
DKN-01 IV Dosing Administered Once Every Two Weeks (Q2W) 
 

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Figure 7: 
Dosing Interval DKN-01 Trough Concentrations (Dose = 300 mg) 
 
1.5.2. 
Rationale for DKN-01 Dose for Part C 
The dosing regimen for both Part C cohorts was informed based on the results of population PK 
(PopPK) and an Exposure-Response assessment for DKN-01.  
Briefly, a PopPK model was developed in January 2022 using data from 369 patients across 6 
DKN-01 studies (DEK-DKK1-P100, DEK-DKK1-P101, DEK-DKK1-P102, DEK-DKK1-
P103, DEK-DKK1-P204, and DEK-DKK1-P205) involving various tumor types. The PopPK 
structural model was a 2-compartment model with first-order elimination. Following 
development of the PopPK model, an exposure-response (E-R) assessment was completed using 
data from Study P102 Part F (N=46 patients) and from Study P205 (N=36 patients) where all 
patients were administered DKN-01 at 300mg on D1 and D15 of Cycle 1. Both actual and 
model predicted exposure metrics, Cmin on Day 21 prior to the administration of the third dose 
of DKN-01, and AUC from time 0 to Day 21, at steady state (AUC0-21, ss) were independently 
evaluated for patients who had disease control (SD) and were protocol responders (PR, or CR) 
as compared to those who were protocol non-responders. Results of these analyses indicated 
that a Cycle 1, Day 21 Cmin ≥60 µg/mL and an AUC0-21, ss >35,000 µg∙hr/mL was associated 
with a greater number of responders suggesting that DKN-01 exposure above these levels may 
be beneficial.  
Using the above described PopPK model predicted DKN-01 parameters, various dosing 
regimens were simulated to estimate exposures at different doses and schedules. From these 
simulation, two DKN-01 dosing regimens were estimated to provide adequate target exposures 
during the first Cycle and over a steady-state Cycle in the majority of patients: 1) 400mg DKN-
01 QW for 3 weeks (Cycle 1 only), followed by a 400mg dose Q2W for subsequent cycles, and 

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2) 600mg DKN-01 on Day 1 and Day 15 (Cycle 1 only), followed by Q3W dosing beginning on 
Day 21. 
For patients in the experimental group for Part C, DKN-01 will be administered at a dose of 600 
mg on D1 of each cycle in combination with tislelizumab, oxaliplatin, and capecitabine 
(CAPOX) in 21-day cycles, or at a dose of 400 mg on D1 of each cycle in combination with 
leucovorin calcium (folinic acid), fluorouracil, and oxaliplatin (mFOLFOX6) in 14-day cycles 
as described in Section 3.1.1.3. For Cycle 1 only, an additional dose of DKN-01 will be 
administered on Day 15 for the CAPOX regimen and on Day 8 for the mFOLFOX6 regimen. 
1.5.3. 
Rationale for Tislelizumab Dose 
The clinical fixed dose of tislelizumab 200 mg IV once every 3 weeks was selected based on 
comparable safety and efficacy profiles between 2 and 5 mg/kg in BGB-A317_Study_001: 
• Rates of treatment-related AEs and SAEs observed in patients receiving 2 mg/kg and 
5 mg/kg once every 2 weeks and once every 3 weeks were comparable, suggesting no 
clear dose-dependence across these regimens. Additionally, PK data also shows no 
relationship between exposure and treatment-emergent irAEs (Wu, Budha et al. 2019a, 
Wu, Tang et al. 2019b). 
• Confirmed response rates in patients treated with tislelizumab on a once every 3 weeks 
schedule were favorable compared to those treated on a once every 2 weeks schedule. 
While there are differences in response rates between dose levels, this is more likely a 
reflection of small sample size and patient heterogeneity than dose response 
• Clearance of tislelizumab was not dependent on body weight, and the observed serum 
exposure of a 200 mg dose fell between serum exposure observed after 2 mg/kg and 
5 mg/kg doses. Therefore, clinical activity with a manageable and tolerable safety 
profile is expected to be maintained in patients receiving tislelizumab 200 mg once 
every 3 weeks 
• Exposure-response analysis indicated that there was a lack of clinically significant 
exposure-response relationships for ORR and safety endpoints across a variety of 
advanced solid tumors and classical Hodgkin lymphoma for tislelizumab. These findings 
support 200 mg once every 3 weeks dose regimen for pivotal studies. 
Tislelizumab is currently tested in clinical studies at the dose of 200 mg every 3 weeks. The 
alternate regimen of 400 mg once every 6 weeks is selected by matching dose and exposure 
(AUC) with the exposure of 200 mg once every 3 weeks regimen. Exposure-response (E-R) 
assessments of available clinical data from Studies including BGB-A317_Study_001, BGB-
A317-102, and BGB-A317-203 suggest no clinically significant relationships observed between 
tislelizumab exposure and efficacy (CR + PR) or safety across tumor types, and the 400 mg 
once every 6 weeks regimen is not expected to be clinically different from the 200 mg once 
every 3 weeks regimen in terms of safety or efficacy outcomes. The higher maximum 
concentrations (Cmax) of 400 mg once every 6 weeks regimen compared with the 200 mg once 
every 3 weeks is well covered by the available safety data at higher doses (10 mg/kg every 2 
weeks and 5 mg/kg every 3 weeks were used in Study BGB-A317_Study_001). Additionally, 
alternative 6-weekly dose administration in adjuvant phase is expected to increase patient 
compliance in this phase and offer additional convenience for care providers. Recently, the 

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approval of the use of an extended dosing regimen has also been reported for other PD-1 
inhibitors such as nivolumab (240 mg Q2W and 480 mg Q4W) and pembrolizumab (200 mg 
once every 3 weeks and 400 mg once every 6 weeks), demonstrating the feasibility and utility 
of this approach (Long et al, 2018; OPDIVO 2014; Lala et al, 2018; Merck Press Release 2019a 
and 2019b; Ebbinghaus, 2019; Holland, 2019).    
In conclusion, the observed clinical activity in patients with advanced tumors, coupled with a 
manageable safety profile and supportive data, support the proposed tislelizumab dose of 
200 mg IV once every 3 weeks and 400 mg IV once every 6 weeks as the recommended dose 
for pivotal studies. Please refer to the Tislelizumab Investigator’s Brochure (BeiGene). 
1.6. 
Benefit-Risk Assessment 
Adverse drug reactions identified during clinical studies with DKN-01 include: 
• Gastrointestinal disorders including nausea, with or without vomiting, constipation, 
and diarrhea 
• Hematologic abnormalities, including thrombocytopenia, neutropenia, and anemia 
• Fatigue. 
The identified risks occur more frequently and at higher grade when DKN-01 is given in 
combination therapy than with DKN-01 monotherapy, as reactions observed with combination 
therapy, to date, appear influenced by safety of the combination partner (paclitaxel, 
gemcitabine/cisplatin, or pembrolizumab). 
DKN-01 is a clinically active drug that has the potential to benefit adult patients across several 
different tumor types where there are unmet medical needs. The safety profile has remained 
favorable across more than 343 oncology patients (including monotherapy, combination 
therapies).  
More than 1273 patients have been treated with tislelizumab monotherapy at clinically relevant 
doses (≥2 mg/kg) with additional patients treated in combination studies. The safety profile is 
largely consistent with that of other anti-PD-1 antibodies and included mostly mild/moderate 
AEs. Very few Grade 3/4 irAEs have been observed, and they have been generally reversible 
and manageable with study drug interruption and/or steroid treatment. These preliminary data 
from the ongoing Phase 1 and Phase 2 studies show that tislelizumab has been well tolerated in 
patients with advanced and refractory tumors, including, but not limited to, triple negative 
breast cancer, NSCLC, cholangiocarcinoma, ovarian, gastric, and HCC, head and neck 
squamous cell carcinoma, esophageal carcinoma, cervical cancer, colorectal cancer, bladder 
cancer, melanoma, Merkel-cell carcinoma, thyroid cancer, and RCC. The safety profile for 
single-agent tislelizumab is similar to those observed in other PD-1 inhibitors. Preliminary data 
from combination studies show a similar safety profile. The initial data collected in these 
studies suggest that tislelizumab can result in antitumor activity across a variety of tumor types. 
Antitumor activity has been observed across the dose ranges evaluated in patients. Therefore, 
the benefit-risk profile for tislelizumab monotherapy appears to be favorable in oncology 
population based on preliminary efficacy and safety data.  
More detailed information about the known and expected benefits and risks and reasonably 
expected AEs of the study treatments can be found in the Tislelizumab Investigator’s Brochure 

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(BeiGene) and DKN-01 Investigator’s Brochure, and in the local prescribing information for 
oxaliplatin and capecitabine. These documents will be used as the reference safety information 
for this clinical study. 

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2. 
STUDY OBJECTIVES AND ENDPOINTS 
2.1. 
Part A and Part B  
2.1.1. 
Study Objectives 
2.1.1.1. 
Primary Objective 
• To characterize the safety and tolerability of DKN-01 in combination with 
tislelizumab ± CAPOX (capecitabine + oxaliplatin) in patients with inoperable, 
locally advanced or metastatic G/GEJ adenocarcinoma. 
2.1.1.2. 
Secondary Objectives  
• Part A: To estimate the ORR of patients with inoperable, locally advanced or 
metastatic G/GEJ adenocarcinoma treated with DKN-01 in combination with 
tislelizumab + CAPOX as a first-line therapy using RECIST v1.1. 
• Part B: To estimate the ORR of patients with inoperable, locally advanced or 
metastatic DKK1-high G/GEJ adenocarcinoma treated with DKN-01 in combination 
with tislelizumab as a second-line therapy using RECIST v1.1. 
• Part A: To estimate duration of response (DoR), duration of complete response 
(DoCR), PFS, OS, duration of clinical benefit (DoCB), durable clinical benefit 
(DCB), DCR, and time to response (TTR) in patients with inoperable, locally 
advanced or metastatic G/GEJ adenocarcinoma treated with DKN-01 in combination 
with tislelizumab + CAPOX as a first-line therapy. 
• Part B: To estimate DoR, DoCR, PFS, OS, DoCB, DCB, DCR, and TTR in patients 
with inoperable, locally advanced or metastatic DKK1-high G/GEJ adenocarcinoma 
treated with DKN-01 in combination with tislelizumab as a second-line therapy. 
2.1.1.3. 
Exploratory Objectives  
• To characterize the PK of DKN-01. 
• To characterize the PK of tislelizumab. 
• To assess the immunogenicity of DKN-01. 
• To assess the immunogenicity of tislelizumab. 
• To assess predictive, prognostic, and/or pharmacodynamic biomarkers and clinical 
characteristics including any association between response, survival, or other clinical 
outcomes and DKN-01 in combination with tislelizumab ± CAPOX. 
• To evaluate biomarkers from patient-derived tumor tissue(s) and/or blood (or blood 
derivative) samples obtained before, during, and/or after treatment with DKN-01 in 
combination with tislelizumab ± CAPOX including assessment of association of 
these biomarkers with clinical outcomes to DKN-01+tislelizumab ± CAPOX. 
• To evaluate exposure-response relationships if the available data permit.  

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• Part A: To estimate the ORR, BOR, DCB rate, and DCR using iRECIST in patients 
with inoperable, locally advanced or metastatic G/GEJ adenocarcinoma treated with 
DKN-01 in combination with tislelizumab + CAPOX as first-line therapy continuing 
treatment beyond the initial assessment of progressive disease. 
• Part B: To estimate the ORR, BOR, DCB rate, and DCR using iRECIST in patients 
with inoperable, locally advanced or metastatic DKK1-high G/GEJ adenocarcinoma 
treated with DKN-01 in combination with tislelizumab as a second-line therapy 
continuing treatment beyond the initial assessment of progressive disease. 
2.1.2. 
Study Endpoints  
2.1.2.1. 
Safety Endpoint 
• Incidence of TEAEs, Grade ≥3 TEAEs, treatment-related TEAEs, treatment-
emergent serious adverse events (TESAEs), treatment-related TESAEs, and 
TEAEs leading to study drug discontinuation. 
2.1.2.2. 
Other Key Safety Endpoints 
• Incidence of treatment-emergent Grade 3/4 clinical laboratory abnormalities. 
• Incidence of treatment-emergent irAEs.  
• Incidence of Grade 3/4 and serious treatment-emergent irAEs.  
• Incidence of Grade 3/4 and serious infusion-related reactions. 
• Changes from baseline in clinical laboratory parameters (serum chemistry and 
hematology). 
• Changes from baseline in vital signs and electrocardiogram (ECG) parameters. 
• Shift from baseline in ECOG performance status. 
2.1.2.3. 
Efficacy Endpoints 
• ORR (the proportion of patients with best overall response of CR + PR), as 
assessed by the Investigator, using RECIST v1.1.  
• DoR, defined as the time from initial response (CR or PR) until radiographically 
documented progressive disease or death due to any cause; progressive disease is 
defined using RECIST v1.1. 
• DoCR, defined as the time from initial CR until radiographically documented 
progressive disease or death due to any cause; progressive disease is defined using 
RECIST v1.1. 
• PFS, defined as the time from first study drug dose (i.e., C1D1) to first 
radiographically documented progressive disease, as determined using RECIST 
v1.1, or death due to any cause. 
• OS, defined as the time from first study drug dose (i.e., C1D1) to death due to any 
cause.  

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• DoCB, defined as the time from the first study drug dose (i.e., C1D1) to the time 
of progressive disease, as determined using RECIST v1.1, or death due to any 
cause in patients who had a best overall response of CR, PR, or SD of ≥6 weeks. 
• DCB, defined as DoCB ≥180 days. Patients who have best overall response of PD 
or those having clinical benefit but DoCB lasting <180 days will be considered as 
“non-DCB”. 
• DCR (i.e., CR+PR+ SD at ≥6 weeks), as assessed by the Investigator, using 
RECIST v1.1. 
• TTR, defined as the time from the first dose of study treatment to the assessment 
date of the BOR of either CR or PR. 
2.1.2.4. 
Exploratory Endpoints  
• Summary of serum concentrations of DKN-01 or tislelizumab at specified timepoints. 
• Incidence of antidrug antibodies (ADAs) to DKN-01 or tislelizumab. 
• Predictive, prognostic, and/or pharmacodynamic biomarkers including any association 
between response, survival, or other clinical outcomes and DKN-01 in combination with 
tislelizumab ± CAPOX. 
• Biomarkers from patient-derived tumor tissue(s) and/or blood (or blood derivative) 
samples obtained before, during, and/or after treatment with DKN-01 in combination 
with tislelizumab ± CAPOX. Biomarkers may include, but are not limited to: 
o DKK1 tumor expression in mRNA by ISH  
o Programmed cell death protein ligand-1 (PD-L1) in the tumor microenvironment 
by IHC 
o circulating tumor deoxyribonucleic acid (ctDNA) 
o serum DKK1. 
• Exposure-response relationships for DKN-01 as data permit.  
• iORR = (number of patients with iCR + iPR)/all patients) based on the Investigator 
assessment and following iRECIST for patients continuing treatment beyond the initial 
assessment of progressive disease. 
2.2. 
Part C 
2.2.1. 
Study Objectives 
2.2.1.1. 
Primary Objective 
• To assess whether the addition of DKN-01 to the combination of tislelizumab + 
chemotherapy regimen (CAPOX or mFOLFOX6 [leucovorin calcium, 
fluorouracil, and oxaliplatin]) improves PFS according to the RECIST v1.1 as 
assessed by the Investigator, in advanced DKK1-high and overall G/GEJ 

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adenocarcinoma compared to tislelizumab + chemotherapy regimen (CAPOX or 
mFOLFOX6) as a first-line therapy. 
2.2.1.2. 
Secondary Objectives 
• To estimate the objective response rate (ORR), according to RECIST v1.1, as 
assessed by the Investigator, the duration of response (DoR) and overall survival 
(OS) in advanced DKK1-high and overall G/GEJ adenocarcinoma patients treated 
with DKN-01 in combination with tislelizumab + chemotherapy regimen 
(CAPOX or mFOLFOX6) compared to tislelizumab + chemotherapy regimen 
(CAPOX or mFOLFOX6) as a first-line therapy.  
• To assess whether the addition of DKN-01 to the combination of tislelizumab + 
chemotherapy regimen (CAPOX or mFOLFOX6) improves PFS and ORR, 
according to RECIST v1.1, as assessed by the Investigator, in patients with CPS 
≥5 or CPS <5 advanced DKK1-high and overall G/GEJ adenocarcinoma 
compared to tislelizumab + chemotherapy regimen (CAPOX or mFOLFOX6) as a 
first-line therapy.  
• To characterize the frequency of toxicity ≥Grade 3 treatment-related adverse 
events (TRAE) associated with each of the treatment arms. 
2.2.1.3. 
Exploratory Objectives  
• To assess whether the addition of DKN-01 to the combination of tislelizumab + 
chemotherapy regimen (CAPOX or mFOLFOX6) improves the duration of 
complete response (DoCR), duration of clinical benefit (DoCB), durable clinical 
benefit (DCB), disease control rate (DCR), and time to response (TTR) in 
advanced DKK1-high and overall G/GEJ adenocarcinoma patients compared to 
tislelizumab + chemotherapy regimen (CAPOX or mFOLFOX6) as a first-line 
therapy. 
• To characterize the PK of DKN-01. 
• To characterize the PK of tislelizumab. 
• To assess the immunogenicity of DKN-01. 
• To assess the immunogenicity of tislelizumab. 
• To assess predictive, prognostic, and/or pharmacodynamic biomarkers and clinical 
characteristics including any association between response, survival, or other 
clinical outcomes of DKN-01 in combination with tislelizumab + chemotherapy 
regimen (CAPOX or mFOLFOX6) compared to tislelizumab + chemotherapy 
regimen (CAPOX or mFOLFOX6) as a first-line therapy. 
• To evaluate exposure-response relationships if the available data permit.  
• To estimate the ORR, BOR, DCB rate and DCR using iRECIST in patients with 
inoperable, locally advanced or metastatic DKK1-high and overall G/GEJ 
adenocarcinoma treated with the combination of tislelizumab + chemotherapy 

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regimen (CAPOX or mFOLFOX6) ± DKN-01 as first-line therapy continuing 
treatment beyond the initial assessment of progressive disease. 
• To assess the concordance between Investigator assessment and central imaging 
assessment for primary and secondary efficacy analyses.  
• To assess the concordance between tumor area positivity (TAP) and CPS PD-L1 
expression for primary and secondary efficacy analyses. 
• To evaluate differences between backbone chemotherapy regimens (CAPOX vs 
mFOLFOX6) in combination with tislelizumab ± DKN-01 for primary and 
secondary efficacy analyses.  
2.2.2. 
Study Endpoints 
2.2.2.1. 
Primary Endpoint  
• PFS, as determined by the Investigator per RECIST v1.1, of DKN-01 plus 
tislelizumab + chemotherapy regimen (CAPOX or mFOLFOX6) versus 
tislelizumab + chemotherapy regimen (CAPOX or mFOLFOX6) in DKK1-high 
and in all patients. 
2.2.2.2. 
Secondary Endpoints 
• ORR, as determined by the Investigator per RECIST v1.1, of DKN-01 plus 
tislelizumab + chemotherapy regimen (CAPOX or mFOLFOX6) versus 
tislelizumab + chemotherapy regimen (CAPOX or mFOLFOX6) in DKK1-high 
and all patients. 
• DoR, as determined by the Investigator per RECIST v1.1, of DKN-01 plus 
tislelizumab + chemotherapy regimen (CAPOX or mFOLFOX6) versus 
tislelizumab + chemotherapy regimen (CAPOX or mFOLFOX6) in DKK1-high 
and all patients. 
• OS with DKN-01 plus tislelizumab + chemotherapy regimen (CAPOX or 
mFOLFOX6) versus tislelizumab + chemotherapy regimen (CAPOX or 
mFOLFOX6) in DKK1-high and in all patients. 
• Incidence of ≥Grade 3 treatment-related adverse events (TRAEs). 
2.2.2.3. 
Exploratory Endpoints  
• DoCR using RECIST v1.1. 
• DoCB as determined using RECIST v1.1, is defined as the time from the date of 
randomization to the time of progressive disease or death due to any cause in patients 
who had a best overall response of complete response (CR), partial response (PR), or 
stable disease (SD) of ≥6 weeks. 
• DCB, defined as DoCB ≥180 days. Patients who have best overall response of PD or 
those having clinical benefit but DoCB lasting <180 days will be considered as “non-
DCB”. 

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• DCR (i.e., CR + PR + SD at ≥6 weeks), as assessed by the Investigator using RECIST 
v1.1. 
• TTR, defined as the time from the date of randomization to the assessment date of the 
first instance of an overall response of CR or PR.  
• Summary of serum concentrations of DKN-01 at specified timepoints. 
• Summary of serum concentrations of tislelizumab at specified timepoints. 
• Incidence of anti-drug antibodies (ADAs) to DKN-01. 
• Incidence of ADAs to tislelizumab. 
• Serum DKK1, change since baseline at specified timepoints (applicable for patients who 
received DKN-01). 
• Exposure-response relationships for DKN-01 as data permit. 
• Biomarkers from patient-derived tumor tissue(s) and/or blood (or blood derivative) 
samples obtained before, during, and/or after treatment with DKN-01 plus tislelizumab 
+ chemotherapy regimen (CAPOX or mFOLFOX6) versus tislelizumab + chemotherapy 
regimen (CAPOX or mFOLFOX6). Biomarkers may include, but are not limited to: 
o DKK1 tumoral mRNA expression by Chromogenic situ hybridization (CISH) 
o Programmed cell death protein ligand-1 (PD-L1) expression by IHC 
o Genetics from tumor specimens or circulating tumor deoxyribonucleic acid 
(ctDNA) 
o Serum and plasma for proteomics and additional scientific analyses. 
• iORR = (number of patients with iCR + iPR)/all patients) based on the Investigator 
assessment and following iRECIST for patients continuing treatment beyond the initial 
assessment of progressive disease. 
• A concordance comparison between Investigator assessment and central imaging 
assessment for primary and secondary efficacy analyses will be performed. 
• A concordance comparison between CPS and TAP will be performed, including 
additional scientific analysis in patients with TAP ≥5 or TAP <5 advanced DKK1-high 
and overall G/GEJ adenocarcinoma compared to tislelizumab + chemotherapy regimen 
(CAPOX or mFOLFOX6) as a first-line therapy. 

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3. 
STUDY DESIGN 
3.1. 
Summary of Study Design 
This is a Phase 2 open-label, multicenter study to be conducted concurrently in 3 parts (non-
randomized Parts A and B and a randomized Part C).  
• Part A will enroll G/GEJ adenocarcinoma patients who have received no prior 
systemic treatment in the locally advanced/metastatic setting (first-line treatment) 
(Section 3.1.1.1) 
• Part B will enroll patients who received only 1 prior systemic treatment, which 
must consist of a platinum and/or fluoropyrimidine–based therapy (± HER2 
therapy if applicable) for locally advanced/metastatic DKK1-high G/GEJ 
adenocarcinoma (second-line treatment) (Section 3.1.1.2) 
• Part C will enroll G/GEJ adenocarcinoma patients who have received no prior 
systemic treatment in the locally advanced/metastatic setting (first-line treatment) 
(Section 3.1.1.3).  
In Parts A and B, approximately 72 adult patients with inoperable, histologically confirmed 
locally advanced or metastatic G/GEJ adenocarcinoma with measurable disease (RECIST v1.1) 
requiring therapy will be enrolled in the study.  
Both Parts A and B are designed to evaluate safety, tolerability, and efficacy of the combination 
therapy of IV DKN-01 and tislelizumab ± CAPOX in G/GEJ adenocarcinoma patients. 
Treatment continues in repeating 21-day cycles until patient meets criteria for discontinuation or 
is no longer deriving clinical benefit. Parts A and B will be enrolled concurrently. A review by 
the Safety Review Team (SRT) will occur in each study part after the first 5 patients have 
completed Cycle 1. Refer to Section 7.2.3 for details on the SRT.  
Part C is the open-label, randomized, controlled, 2-arm portion of the study to evaluate the 
efficacy and safety of tislelizumab + chemotherapy regimen (CAPOX or mFOLFOX6) ± DKN-
01 in adult patients with inoperable, histologically confirmed locally advanced or metastatic 
G/GEJ adenocarcinoma with measurable disease (RECIST v1.1) requiring therapy. 
Approximately 160 patients will be randomized in a 1:1 ratio to receive either DKN-01 in 
combination with tislelizumab and chemotherapy regimen (CAPOX or mFOLFOX6) (n=80) or 
tislelizumab in combination with chemotherapy regimen (CAPOX or mFOLFOX6) (n=80), 
Patients will be assigned to treatment using a central stratified block randomization scheme. 
Patients will be stratified at randomization by the following factors: 
• DKK1 RNAscope tumor percentage score (TPS) (≥20% vs <20%)  
• PD-L1 immunohistochemistry Combined Positive Score (CPS) (≥5 vs <5). 
Randomization may occur up to 3 calendar days prior to C1D1. 
For Part C, a review by the SRT will occur after the first 5 patients on each chemotherapy 
regimen (CAPOX and mFOLFOX6) have completed Cycle 1 from both the experimental group 
(i.e., DKN-01 in combination of tislelizumab and chemotherapy regimen) and the control group 
(i.e., tislelizumab and chemotherapy regimen). Enrollment will continue during the safety data 
review without pause (refer to Section 7.2.3 for details on the SRT).  

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3.1.1. 
Treatment 
3.1.1.1. 
Part A 
Part A patients will receive treatment as outlined in Figure 8. Part A is restricted to patients who 
have not had prior systemic therapy for locally advanced or metastatic disease. Patients may 
have received prior neoadjuvant or adjuvant therapy as long as it was completed without disease 
recurrence for at least 6 months. A review by the SRT will occur after the first 5 patients have 
enrolled and completed 1 cycle. Enrollment in the other ongoing cohorts may continue during 
the SRT review. 
Figure 8: 
Study Design Part A 
 
Abbreviations: BID = twice daily; EOT = end of treatment. 
3.1.1.2. 
Part B 
Part B patients will receive IV DKN-01 (300 mg or 600 mg) on Days 1 and 15 and IV 
tislelizumab (200 mg) on Day 1 of each 21-day cycle. 
Part B has 2 components:  
• The first 24 patients (Part B1) will receive DKN-01 300 mg (Figure 9) 
• The next 24 patients (Part B2) will receive DKN-01 600 mg (Figure 10).  
Patients enrolled in Part B are required to have DKK1-high (H-score ≥35) G/GEJ 
adenocarcinoma (pre-screen biopsy) and must have had only 1 prior systemic therapy for 
locally advanced/metastatic disease (platinum and/or fluoropyrimidine-based therapy; ± HER2 
therapy if applicable). Patients may have received prior neoadjuvant or adjuvant therapy (see 
Section 4.2.2). A safety review will occur after the first 5 patients in each of Part B1 and B2 
have enrolled and completed 1 cycle.  

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It is anticipated that Part B2 will enroll following the completion of enrollment of all patients in 
Part B1. Enrollment in the other ongoing cohorts (e.g., Part A) may continue during the SRT 
review. 
Figure 9: 
Study Design Part B1 
 
Abbreviations: EOT = end of treatment. 
 
Figure 10: 
Study Design Part B2  
 
Abbreviations: EOT = end of treatment. 

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3.1.1.3. 
Part C 
Part C patients will be randomized using a central stratified block randomization scheme into 
one of 2 groups: patients in the experimental group will receive DKN-01 in combination with 
tislelizumab and chemotherapy regimen (CAPOX or mFOLFOX6) and patients in the control 
group will receive only tislelizumab in combination with chemotherapy regimen (CAPOX or 
mFOLFOX6). The randomization will use the following stratification factors: 
• DKK1 RNAscope TPS (≥20% vs <20%)  
• PD-L1 immunohistochemistry CPS (≥5 vs <5). 
Note: To avoid unnecessary delays which could impact patient care, during the Screening 
Period, patients who in the opinion of the Investigator are unable to wait more than 2 weeks to 
start treatment, may receive one cycle of chemotherapy (CAPOX or mFOLFOX6) prior to 
randomization while awaiting biomarker results. Patients meeting these requirements should be 
discussed with the Medical Monitor. 
Once DKK1 and PD-L1 results from the central laboratory are received and the patient has been 
confirmed to meet all other eligibility requirements, the patient will be randomized to receive 
either DKN-01 in combination with tislelizumab and chemotherapy (CAPOX or mFOLFOX6) 
or tislelizumab in combination with chemotherapy (CAPOX or mFOLFOX6). If the central lab 
is unable to result a PD-L1 CPS score, historical CPS data can be used provided it was 
generated using either the 22C3 pharmDx, 28-8 pharmDx or SP263 assays. The chemotherapy 
regimen administered during Screening must be equivalent to that following randomization.  
Patients in both groups receiving the CAPOX chemotherapy regimen (Figure 11) will receive 
tislelizumab (200 mg, IV) on Day 1 of each 21-day cycle. The CAPOX regimen will include 
oxaliplatin 130 mg/m2 on Day 1 and capecitabine 1000mg/m2 BID on Days 1-15 of each 21-day 
cycle for a total of 28 doses. Patients in the experimental group will receive DKN-01 (600 mg, 
IV) on Day 1 of each cycle. For Cycle 1 only, an additional loading dose of DKN-01 (600 mg, 
IV) will be administered on Day 15. Patients in the control group will not receive DKN-01 
treatment. 
Patients in both groups receiving the mFOLFOX6 chemotherapy regimen (Figure 12) will 
receive tislelizumab (400 mg, IV) every 6 weeks starting on C1D1 and continuing every third 
14-day cycle (e.g., C4D1, C7D1, etc.). The mFOLFOX6 regimen will be administered every 
14 days and includes leucovorin calcium (folinic acid) 400 mg/m2 IV on Day 1, fluorouracil 400 
mg/m2 IV bolus followed by 2400 mg/m2 continuous infusion over 48 hours and oxaliplatin 85 
mg/m2 IV on Day 1. Patients in the experimental group will receive DKN-01 (400 mg, IV) on 
Day 1 of each cycle. For Cycle 1 only, an additional loading dose of DKN-01 (400 mg, IV) will 
be administered on Day 8. Patients in the control group will not receive DKN-01 treatment. 
For Part C, a review by the SRT will occur after the first 5 patients on each chemotherapy 
regimen (CAPOX and mFOLFOX6) have completed Cycle 1 from both the experimental group 
(i.e., DKN-01 in combination of tislelizumab and chemotherapy regimen) and the control group 
(i.e., tislelizumab and chemotherapy regimen) Enrollment will continue during the safety data 
review without pause. Refer to Section 7.2.3 for details on the SRT.   

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Figure 11: 
Study Design Part C (CAPOX regimen) 
 
Abbreviation: BID = twice daily; EOT = end of treatment; q = every 
Note: For Cycle 1 only, an additional loading dose of DKN-01 (600 mg, IV) will be administered on Day 15. 
 
Figure 12: 
Study Design Part C (mFOLFOX6 regimen) 
 
Abbreviation: EOT = end of treatment; q = every. 
Note: For Cycle 1 only, an additional loading dose of DKN-01 (400 mg, IV) will be administered on Day 8. 

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The study consists of a Pre-Screening Period (Part B only; Section 3.1.1.3), a Screening Period 
(Section 3.1.3), a Treatment Period (Section 3.1.4), and a Follow-up Period. The Follow-up 
Period includes a follow-up visit approximately 30 days after the last dose of study drug 
(Section 3.1.6) and provides for additional long-term follow-up for disease progression (if the 
patient discontinued study drug for a reason unrelated to progressive disease) and for 
subsequent therapies and survival until death (in all patients) (Section 3.1.7). After treatment 
discontinuation, patients will enter a long-term follow-up period. The Sponsor has the right to 
terminate this study at any time.  
3.1.2. 
Pre-Screening (Part B Only) 
Patients participating in Part B will agree to and sign a Pre-Screening informed consent to allow 
tumor biopsy tissue to be tested for DKK1 expression. No screening procedures will be allowed 
by this consent.  
A fresh tumor biopsy sample (preferred) or an archived specimen will be sent to a Sponsor-
designated, College of American Pathologists (CAP)-/Clinical Laboratory Improvement 
Amendments (CLIA)-certified central laboratory for evaluation of DKK1 mRNA in the tumor 
cells. If the patient’s specimen testing result demonstrates elevated DKK1 (H-score ≥35), then 
the patient will be eligible for Screening in Part B. If the patient’s specimen testing 
demonstrates an H-score <35, then the patient is ineligible for the study. 
3.1.3. 
Screening Period 
Patients who agree to participate in this study will sign the informed consent form (ICF) prior to 
undergoing any screening procedure. Results of standard-of-care tests or examinations 
performed prior to obtaining informed consent and <28 days prior to enrollment (C1D1) may be 
used for the purposes of screening rather than repeating the standard-of-care tests. 
Screening evaluations may be performed within 28 days (35 days for imaging in Part C) prior to 
first dose of study drug. Hematology, chemistry, pregnancy testing, and ECG must be resulted, 
and treatment eligibility confirmed prior to dosing on C1D1 (Part B), or treatment eligibility 
confirmed prior to randomization (Part C). 
Patients in the Republic of Korea who are suspected to have concurrent serious respiratory 
illness or exhibit significant respiratory symptoms unrelated to underlying cancer will also take 
a pulmonary function test (refer to Appendix 1 for details).  
Screening evaluations may be repeated as needed within the Screening period; the Investigator 
is to assess preliminary patient eligibility according to the latest Screening assessment results. 
Part B  
The biopsy sample (fresh [preferred] or archival) collected during the Pre-screening period will 
be used to confirm elevated DKK1 mRNA levels required to meet eligibility criteria for 
enrollment (H-score ≥35). A fresh biopsy will be collected during the Screening period (+ 
14 days) from patients who did not undergo a biopsy during the Pre-screening period for 
evaluation of DKK1 mRNA levels (unless it is clinically contraindicated per Investigator and 
after consultation with the Medical Monitor) for a retrospective DKK1 mRNA analysis.  

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Part C 
Once eligibility for entry into the study is confirmed, patients will be randomized to receive 
either DKN-01 in combination with tislelizumab and chemotherapy regimen (CAPOX or 
mFOLFOX6) or tislelizumab in combination with chemotherapy regimen (CAPOX or 
mFOLFOX6) using a central stratified block randomization scheme. The stratification factors 
will be as follows: 
• DKK1 RNAscope TPS (≥20% vs <20%)  
• PD-L1 immunohistochemistry CPS (≥5 vs <5). 
Randomization may occur up to 3 calendar days prior to C1D1. The EDC (Electronic Data 
Capture) system will be used to assign patients to either the experimental group or the control 
group in lieu of a separate IRT (Interactive Response Technology) system. Detailed instructions 
for assigning treatment will be provided in the eCRF completion guidelines.  
3.1.4. 
Treatment Period 
After completion of all Screening activities, treatment eligibility will be reconfirmed by 
performing safety labs within 3 days prior to dosing on C1D1 (refer to Section 5.2.3). On C1D1, 
qualified patients will receive study treatment as outlined in Table 8.  
Blood sampling for clinical safety laboratory tests will be taken throughout the treatment period 
according to the schedule detailed in the Study Schedules (Appendix 1). Unscheduled visits (see 
Section 6.1.2) may occur if the Investigator deems appropriate. 
Radiological assessment of tumor-response status will be performed as described in Section 6.4. 
Safety will be assessed throughout the study by monitoring AEs/SAEs (toxicity grades assigned 
per National Cancer Institute Common Terminology Criteria for Adverse Events [NCI-CTCAE, 
v5.0]) and laboratory results. Vital signs, physical examinations, ECOG performance status 
change, electrocardiogram (ECG) results, and other examinations will also be used for safety 
assessment as detailed in the Schedule of Assessments (Appendix 1). 
All patients who continue to meet criteria for retreatment (refer to Section 5.2.3) will continue 
study treatment in the Treatment Period until development of radiographically documented 
progressive disease, unacceptable toxicity, or another discontinuation criterion is met, as 
determined by the Investigator or until a patient reaches 2 years of treatment as outlined below 
(as measured from C1D1).  
When a patient reaches 2 years of treatment (as measured from C1D1): 
• Patients may continue on study drugs beyond 2 years if the Investigator considers 
this to be in the best interest of the patient based on an assessment of clinical benefit 
and potential risks. Continuation of study drugs beyond 2 years must be explicitly 
approved by the Sponsor and will be contingent on the continued availability of 
DKN-01 and tislelizumab. The study assessment and procedure schedule will remain 
the same 
• Patients with confirmed CR, PR, or SD may stop treatment after 2 years if the 
patient wishes. The decision should be based on the Investigator’s evaluation, with 
the patient’s clinical benefit and risk taken into consideration. The Investigator 

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should notify the Sponsor that treatment will be stopped prior to stopping the 
treatment 
Treatment beyond the initial Investigator-assessed, RECIST v1.1 defined disease progression is 
permitted provided that the patient has Investigator-assessed clinical benefit and is tolerating the 
study drugs (refer to Section 5.2.3 for further details). Tumor assessment in such patients should 
continue as planned until study treatment discontinuation. 
3.1.5. 
End of Treatment 
The End-of-Treatment Visit (EOT) visit is conducted when the Investigator determines that 
DKN-01 will no longer be used for Part A and Part B. The End-of-Treatment (EOT) visit is 
conducted when the patient is no longer deriving clinical benefit from all study treatments and 
the Investigator determines all treatment should end in Part C. The reason for discontinuation 
from study treatment will be documented in the electronic case report form (eCRF). If routine 
laboratory tests (e.g., hematology, serum chemistry) are completed within 7 days before the 
EOT visit, these tests need not be repeated. Tumor assessment should follow the regular 
schedule of assessment in Appendix 1. If a patient has known positive ADA (to DKN-01 or 
tislelizumab) at the EOT visit, he or she should have repeat testing, where feasible, performed in 
the PD Follow-up Period and/or Survival Follow-up Period until the patient is no longer 
positive. If a female patient is of childbearing potential, she will be followed monthly with a 
urine pregnancy test up to 6 months following the last dose of study drug. This testing can occur 
with a primary care physician and documentation made available to the study team. Male 
subjects will be asked during the PD and/or survival follow up period, if their female partners 
have experienced a pregnancy.  
3.1.6. 
Safety Follow-up 
Patients who discontinue treatment for any reason will be asked to return to the clinic for the 
Safety Follow-up Visit (to occur within 30 days [+ 7 days] after the last dose of study drugs, or 
before the initiation of a new anticancer treatment, whichever occurs first). If the EOT and 
Safety Follow-up Visits are planned to be conducted within 7 days of one another, the visit 
procedures from these visits may be combined and completed at the EOT visit, and the Safety 
Follow-up visit may be conducted instead as a telephone call to document AEs and concomitant 
medications/procedures. 
In addition, telephone contacts with patients should be conducted to assess immune-related AEs 
and concomitant medications (if appropriate, i.e., associated with an immune-related AE or is a 
new anticancer therapy) at 60 days and 90 days (± 14 days) after the last dose of study 
treatment, regardless of whether or not the patient starts a new anticancer therapy. If patients 
report a suspected immune-related AE at a telephone follow-up contact, the Investigator should 
arrange an unscheduled visit if further assessment is indicated. Women of childbearing potential 
will continue to have pregnancy tests monthly for up to 6 months following last dose of study 
drug. This testing can occur with a primary care physician and documentation made available to 
the study team. Male subjects will be asked during the PD and/or survival follow up period, if 
their female partners have experienced a pregnancy. 
All AEs, including SAEs, will be collected as described in Section 7. 

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3.1.7. 
PD and Survival Follow-up 
Patients will be followed for survival and to obtain information on subsequent anticancer 
therapy information after discontinuation of study treatment via telephone calls, patient medical 
records, and/or clinic visits approximately every 12 weeks (± 14 days) after the EOT Visit or as 
directed by the Sponsor until death, withdrawal of consent, loss to follow-up, or end of study. 
Patients who do not have PD when they discontinue study treatment will be followed 
approximately every 12 weeks in the PD Follow-up Period per routine clinical practice until 
documented disease progression, start of new anti-cancer medicine, death, withdrawal of 
consent, or study closure. After documentation of PD, all patients will be followed 
approximately every 12 weeks per routine clinical practice during the Survival Follow-up 
Period for survival until death, withdrawal of consent, or study closure. 
If a patient has known positive ADA (to DKN-01 or tislelizumab) at the EOT visit, he or she 
should have repeat testing, where feasible, performed in the PD Follow-up Period and/or 
Survival Follow-up Period until the patient is no longer positive. Women of childbearing 
potential will continue to have pregnancy tests monthly for up to 6 months following last dose 
of study drug. This testing can occur with a primary care physician and documentation made 
available to the study team. Male subjects will be asked during the PD and/or survival follow up 
period, if their female partners have experienced a pregnancy. 
3.2. 
Discontinuation From the Study Treatment or From the Study 
3.2.1. 
Patient Discontinuation from Study Treatment 
Patients have the right to discontinue study treatment at any time for any reason. In addition, the 
Investigator has the right to discontinue a patient from the study treatment at any time. Patients 
who discontinue study treatment for reasons other than disease progression or withdrawal of 
consent should be followed for assessments of antitumor activity, subsequent anticancer 
therapy, and survival (Section 3.1.7), if possible. Patients who discontinue study treatment for 
disease progression should be followed for subsequent anticancer therapy and survival 
(Section 3.1.7).  
The primary reason for discontinuation from the study treatment should be documented on the 
appropriate eCRF. Patients may discontinue study treatment for reasons which include, but are 
not limited to, the following: 
• Disease progression 
• Adverse event 
• Use of any concurrent anticancer therapy (i.e., chemotherapy, hormonal therapy, 
immunotherapy, or standard or investigational agents [including herbal medicine] for the 
treatment of cancer) 
• Patient noncompliance: Investigative site staff should first counsel patients who are 
significantly noncompliant (e.g., missing 2 treatment cycles) on the importance of study 
drug compliance and drug accountability. The Investigator may, in consultation with the 
Medical Monitor, discontinue patients from treatment who are consistently 
noncompliant. 

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Patients must be discontinued from study treatment for the following reasons:  
• Pregnancy 
• Patient decision 
• Any medical condition that the Investigator or Sponsor determines may jeopardize the 
patient’s safety, if he or she were continue the study treatment. (see section 5.2.2.2 and 
Appendix 7 and 8 for AEs and when discontinuation is required for safety). 
3.2.2. 
Patient Discontinuation from Study  
Patients will discontinue study for reasons which include, but are not limited to, the following:  
• Patient withdrawal of consent 
• Death 
• Lost to follow-up 
3.3. 
End of Study 
The end of study is defined as the timepoint when, to the Sponsor’s knowledge, the final data 
point is collected from the last patient in the study. This is when the last patient dies, withdraws 
consent, completes all study assessments, or is lost to follow-up. Alternatively, the end of study 
is when the Sponsor decides to terminate the study. 
The Sponsor has the right to terminate this study at any time. Reasons for terminating the study 
early may include, but are not limited to, the following: 
• The incidence or severity of AEs in this or other studies indicates a potential health 
hazard to patients. 
• Overall patient enrollment is unsatisfactory. 
The Sponsor will notify each Investigator if a decision is made to terminate the study. Should 
this be necessary, prematurely discontinued patients should be seen as soon as possible for an 
EOT Visit and Safety Follow-up Visit. 
The Investigators may be informed of additional procedures to be followed to ensure that 
adequate consideration is given to the protection of the patient’s interests. The Investigator will 
be responsible for informing Institutional Review Boards (IRBs)/Independent Ethics 
Committees (IECs) of the early termination of the study. 
At the end of study, any patients who, in the opinion of the Investigator, continue to benefit 
from tislelizumab or DKN-01 at study termination, will be offered the option to continue 
treatment in a company-sponsored clinical study until it is commercially available in the 
country of the patient’s residence. 

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4. 
STUDY POPULATION 
4.1. 
Number of Patients 
Approximately 232 adult patients will be enrolled to ensure a minimum of 220 evaluable 
patients. Expected enrollment in each cohort as follows: 
• Part A: Approximately 24 patients with treatment-naïve inoperable, locally advanced or 
metastatic G/GEJ adenocarcinoma will be enrolled to ensure 20 evaluable patients. 
• Part B: Approximately 48 patients with previously treated inoperable, locally advanced or 
metastatic DKK1-high G/GEJ adenocarcinoma will be enrolled to ensure 40 evaluable 
patients. 
• Part C: Approximately 160 patients with treatment-naïve inoperable, locally advanced or 
metastatic G/GEJ adenocarcinoma will be randomized and enrolled in 2 treatment groups 
to ensure 80 evaluable patients per treatment group. 
Prospective approval of protocol deviations to recruitment and enrollment criteria, also known 
as protocol waivers or exemptions, is not permitted. 
 
In Part C, the enrollment assumptions will be monitored during the enrollment period; thus 
sample size and timeline could be adjusted accordingly. 
4.2. 
Inclusion Criteria 
Patients meeting all the following criteria will be considered eligible for study entry:  
4.2.1. 
Part A and C only 
1. No previous systemic therapy for inoperable, locally advanced or metastatic G/GEJ 
adenocarcinoma.  
a. Patients may have received prior neoadjuvant or adjuvant therapy as long as it was 
completed without disease recurrence for at least 6 months since last treatment. 
b. Patients in Part C may receive one cycle of chemotherapy (CAPOX or mFOLFOX6) 
during screening to avoid unnecessary delays in patient care, if deemed appropriate 
by the PI. 
4.2.2. 
Part B only 
2. Documented objective radiographic or symptomatic disease progression following first-line 
therapy with any platinum and/or fluoropyrimidine-based regimen for unresectable or metastatic 
disease.  
a. Patients may have received prior neoadjuvant or adjuvant therapy. If progression has 
occurred within 6 months from last dose of neoadjuvant or adjuvant treatment, this regimen 
will be considered as 1 line of therapy for advanced disease. 
b. Prior trastuzumab (or biosimilar) treatment is acceptable for patients with history of HER2-
positive G/GEJ adenocarcinoma. 
c. Prior therapy with an anti-programmed cell death protein 1 (PD-1), anti-PD-L1 in any 
treatment setting (including adjuvant/neoadjuvant) is acceptable. 

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3. Documentation of elevated DKK1 mRNA expression in tumor cells from a fresh tumor 
biopsy (preferred) or archived tumor biopsy specimen. High DKK1 is defined as an H-score 
≥35 in mRNA by ISH conducted in a Sponsor-designated central laboratory. 
4.2.3. 
Part C only 
4. Documentation of PD-L1 CPS by IHC and DKK1 mRNA expression in tumor cells by ISH 
from a fresh tumor biopsy (preferred) or archived tumor biopsy specimen conducted in a 
Sponsor designated central laboratory. If the central lab is unable to result a PD-L1 CPS score, 
historical CPS data can be used provided it was generated using either the 22C3 pharmDx, 28-8 
pharmDx or SP263 assays. 
4.2.4. 
General 
5. Able to provide written informed consent and can understand and agree to comply with the 
requirements of the study and the schedule of assessments. 
6. Age ≥18 years on the day of signing the informed consent  (exception: ≥19 years in the 
Republic of Korea) . 
7. Histologically proven gastric adenocarcinoma or Siewert I-III GEJ adenocarcinoma. 
8. At least one measurable lesion on radiographic imaging as defined by RECIST v1.1 
(Appendix 4).  
a. A lesion in an area subjected to prior loco-regional therapy, including previous 
radiotherapy, is not considered measurable unless there has been demonstrated 
progression in the lesion since the therapy as defined by RECIST v1.1 
b. Previously irradiated lesions can only be considered as measurable disease if disease 
progression has been unequivocally documented at that site since radiation and the 
previously irradiated lesion is not the only site of disease. 
 
9. Tumor tissue for mandatory pre-treatment evaluation (fresh biopsy [preferred] or archived 
specimen).  
10. ECOG performance status ≤1 within 7 days of first dose of study drug (Appendix 3).  
11. Acceptable liver function: 
a. Parts A and B only 
i. Total bilirubin ≤2.0 times upper limit of normal (ULN). Total bilirubin must be 
<3 × ULN for patients with Gilbert’s syndrome 
ii. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤3 times 
ULN (if liver metastases are present, then ≤5 × ULN is allowed). 
b. Part C only 
i. Total bilirubin ≤2.0 times upper limit of normal (ULN) 
ii. AST and ALT ≤2.5 times ULN  

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1. If liver metastases are present, then ≤5 × ULN is allowed (excluding 
Republic of Korea). 
12. Acceptable renal function: 
a. Serum creatinine ≤1.5 × ULN or estimated glomerular filtration rate 
≥30 mL/min/1.73 m2 by Chronic Kidney Disease Epidemiology 
Collaboration equation (Appendix 9). 
13. Acceptable hematologic status (in the Republic of Korea patients must not have required 
blood transfusion or growth factor support within 14 days before sample collection at Screening 
for the following): 
a. Absolute neutrophil count (ANC) ≥1.5 × 109/L 
b. Platelets: 
i. Part A and C only: ≥100 × 109/L  
ii. Part B only: ≥75 × 109/L 
c. Hemoglobin ≥9 g/dL. 
14. Acceptable coagulation status: 
a. Prothrombin time/activated partial thromboplastin time ≤1.2 × ULN (unless 
receiving anticoagulation therapy, if receiving anticoagulation therapy, 
eligibility will be based upon international normalized ratio [INR]) see (b)(i) 
below 
b. INR ≤1.5 (unless receiving anticoagulation therapy) 
i. If receiving anticoagulant: INR ≤3.0 and no active bleeding (i.e., no 
clinically significant bleeding within 14 days prior to first dose of study 
drugs). 
15. Females of childbearing potential must be willing to use a highly effective method of birth 
control (Appendix 10) for the duration of the study, and for at least 6 months after the last dose 
of study drugs, and have a negative urine or serum pregnancy test within 7 days before first 
dose of study drugs. 
16. Non-sterile males must be willing to use a highly effective method of birth control 
(Appendix 10) for the duration of the study and for at least 6 months after the last dose of study 
drugs 
a. A sterile male is defined as one for whom azoospermia has been previously 
demonstrated in a semen sample examination as definitive evidence of 
infertility 
b. Males with known “low sperm counts” (consistent with “sub-fertility”) are 
not to be considered sterile for purposes of this study.  
4.3. 
Exclusion Criteria  
Patients meeting any of the following criteria are not eligible for study entry: 
4.3.1. 
Part A and C only 
1. Diagnosis of HER2-positive G/GEJ adenocarcinoma. 

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2. Unable to swallow capsules or disease significantly affecting gastrointestinal function such 
as malabsorption syndrome, resection of the stomach or small bowel, bariatric surgery 
procedures, symptomatic inflammatory bowel disease, or partial or complete bowel obstruction 
(for those receiving CAPOX in Part C). 
3. Prior therapy with an anti-programmed cell death protein 1 (PD-1) or anti-PD-L1 antibody. 
4.3.2. 
Part B only 
4. Systemic anti-cancer therapy (e.g., chemotherapy or immunotherapy) within 21 days prior 
to first dose of study drug. 
4.3.3. 
General 
5. Squamous cell or undifferentiated or other histological type of gastric cancer. 
6. Prior therapy with an anti-PD-L2 or any other antibody or drug specifically targeting T-cell 
co-stimulation or co-inhibitory checkpoint pathways in any treatment setting (including 
adjuvant/neoadjuvant) or prior therapy with an anti-DKK1 agent. (Part B exception, see entry 
criterion 2c). 
7. Active autoimmune diseases or history of autoimmune diseases that may relapse (refer to 
Appendix 5). 
a. Note: Patients with the following diseases are not excluded and may proceed to 
further screening: 
i. Controlled Type I diabetes 
ii. Hypothyroidism (provided it is managed with hormone replacement therapy 
only) 
iii. Controlled celiac disease 
iv. Skin diseases not requiring systemic treatment (e.g., vitiligo, psoriasis, alopecia) 
v. Any other disease that is not expected to recur in the absence of external 
triggering factors. 
 
8. Any condition that required treatment with corticosteroids (≥10 mg per day prednisone or 
equivalent) or other immune suppressive drugs within the 14 days prior to first dose of study 
drug. 
a. Note: Patients who are currently or have previously been on any of the following 
steroid regimens are not excluded: 
i. Adrenal replacement steroid (dose ≤10 mg daily of prednisone or equivalent) 
ii. Topical, ocular, intra-articular, intranasal, or inhaled corticosteroid with minimal 
systemic absorption 
iii. Short course (≤7 days) of corticosteroid prescribed prophylactically (e.g., for 
contrast dye allergy) or for the treatment of a non-autoimmune condition (e.g., 

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delayed-type hypersensitivity reaction caused by contact allergen). 
9. Active leptomeningeal disease or uncontrolled brain metastases. Patients with equivocal 
findings or with confirmed brain metastases are eligible for the study provided that they are 
asymptomatic and radiologically stable without the need for corticosteroid treatment or seizure 
prophylaxis for ≥4 weeks before first dose of study drug.  
10. Any active malignancy ≤2 years before first dose of study drug, with the exception of the 
specific cancer under investigation in this study and any locally recurring cancer that has been 
treated curatively (e.g., resected basal or squamous cell skin cancer, superficial bladder cancer, 
carcinoma in situ of the cervix or breast). 
11. Uncontrolled diabetes or >Grade 1 laboratory test abnormalities in potassium, sodium, or 
corrected calcium despite standard medical management or ≥Grade 3 hypoalbuminemia 
within 14 days before first dose of study drug. 
12. Uncontrollable pleural effusion, pericardial effusion, or ascites requiring frequent drainage 
within 7 days prior to first dose of study drug (the cytological confirmation of any effusion is 
permitted). 
13. Clinically significant anorexia (CTCAE ≥Grade 2) within 7 days prior to first dose of study 
drug. 
14. History of interstitial lung disease, non-infectious pneumonitis, pulmonary fibrosis, acute 
lung disease or uncontrolled systemic diseases.  
a. Patients with radiation pneumonitis may be eligible for the study if the radiation 
pneumonitis has been confirmed as stable (beyond acute phase) without any 
concerns about recurrence. Patients with severe but stable radiation-induced 
pneumonitis may be required to undergo routine pulmonary function studies. 
15. Severe chronic or active infections requiring systemic antibacterial, antifungal, or antiviral 
therapy, including tuberculosis infection within 14 days of first dose of study drug. 
16. Prior allogeneic stem cell transplantation or organ transplantation. 
17. History of severe hypersensitivity reactions to other monoclonal antibodies or any 
components of study treatment. 
18. Known dihydropyrimidine dehydrogenase deficiency. 
19. Any of the following cardiovascular risk factors: 
a. Cardiac chest pain, defined as moderate pain that limits instrumental activities of 
daily living within 28 days before first dose of study drug 
b. Pulmonary embolism within 28 days before first dose of study drug 
c. Any history of acute myocardial infarction within 6 months before first dose of study 
drug 
d. Any history of heart failure meeting New York Heart Association (NYHA) 
Classification III or IV (Appendix 6) within 6 months before first dose of study drug 
e. Any event of ventricular arrhythmia ≥Grade 2 in severity within 6 months before 

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first dose of study drug 
f. Any history of cerebrovascular accident within 6 months before first dose of study 
drug 
g. Uncontrolled hypertension that cannot be managed by standard anti-hypertension 
medications within 28 days before first dose of study drug 
h. Any episode of syncope or seizure within 28 days before first dose of study drug. 
20. Fridericia-corrected QT interval >470 msec (female) or >450 (male), or history of 
congenital long QT syndrome. Any electrocardiogram (ECG) abnormality that in the opinion of 
the Investigator would preclude safe participation in the study; patients with pacemakers where 
QTc is not a reliable measure will require an evaluation by a cardiologist to exclude co-existing 
cardiac conditions which would prohibit safe participation in the study.  
21. Known to be human immunodeficiency virus (HIV) positive unless HIV ribonucleic acid 
(RNA) is undetected; known to have active hepatitis B (acute or chronic infection requiring 
antiviral treatment; hepatitis B surface antigen-positive) or have hepatitis C antibodies unless 
hepatitis C virus RNA is undetected/negative. 
22. Serious nonmalignant disease or other circumstance that could compromise protocol 
objectives in the opinion of the Investigator and/or the Sponsor. 
23. History of osteonecrosis of the hip or have evidence of structural bone abnormalities in the 
proximal femur on magnetic resonance imaging (MRI) scan that are symptomatic and clinically 
significant. Degenerative changes of the hip joint are not exclusionary. Screening of patients is 
not required. 
24. Known osteoblastic bony metastasis. Screening of patients without a history of metastatic 
bony lesions is not required. 
25. History of gastrointestinal perforation and/or fistulae within 6 months prior to first dose of 
study drug, clinically significant bleeding from the gastrointestinal tract within 1 month prior to 
first dose of study drug, or clinically significant bowel obstruction (CTCAE ≥Grade 2). 
26. Major surgery within 4 weeks of first dose of study drug. 
27. Serious psychiatric or medical conditions that could interfere with treatment. 
28. Toxicities (as a result of prior anticancer therapy) that have not recovered to baseline or 
stabilized, except for AEs not considered a likely safety risk (e.g., alopecia, neuropathy and 
specific laboratory abnormalities). 
29. Administration of a live vaccine within 28 days before first dose of study drug. 
a. Note: Seasonal vaccines for influenza or COVID vaccines are generally inactivated 
vaccines and are allowed. Intranasal vaccines are live vaccines and are not allowed. 
30. Underlying medical conditions (including laboratory abnormalities) or alcohol or drug abuse 
or dependence that will be unfavorable for the administration of study drug, or affect the 

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explanation of drug toxicity or AEs, or result in insufficient or impaired compliance with study 
conduct. 
31. Women who are pregnant or are breastfeeding. 
32. Concurrent participation in another therapeutic clinical study. 
a. Note: Concurrent participation in observational or non-interventional studies is 
allowed. In addition, patients who have completed active treatment in a clinical 
study and are in the follow-up period can be enrolled in this study. 
33. Treatment with radiation therapy within 14 days prior to first dose of study drug. 

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5. 
STUDY TREATMENTS 
Study interventions are all pre-specified, investigational and non-investigational medicinal 
products, medical devices and other interventions (e.g., surgical and behavioral) intended to be 
administered to the study patients during the study conduct. Only the necessary and least 
invasive interventions are included.  
5.1. 
Identity of Investigational Products, Packaging, and Handling 
5.1.1. 
DKN-01 
DKN-01 supplied for this study is for investigational use and only to be used within the context 
of this clinical study. DKN-01 will be supplied to the Investigator by Leap or its designee. 
DKN-01 is provided in a glass vial as a lyophilized powder for reconstitution. Each vial is 
manufactured to deliver 20 mg of DKN-01 and contains the inactive ingredients sucrose, 
polysorbate 80, sodium chloride, citric acid, and sodium citrate. DKN-01 vials should be stored 
refrigerated at 2ºC – 8ºC. 
Vials of DKN-01 are manufactured in accordance with Good Manufacturing Practices and 
packaged and labeled to meet applicable local regulatory requirements. Study drug labels will 
not bear any statement that is false or misleading in any manner or represent that the study drug 
is safe or effective for the purposes for which it is being investigated. 
Detailed instructions for the preparation and handling of DKN-01 will be provided by Leap or 
its designee in the Pharmacy Manual.  
5.1.2. 
Tislelizumab 
Tislelizumab is a monoclonal antibody formulated for IV injection in a single-use vial (20R 
glass, United States Pharmacopeia type I), containing a total of 100 mg of antibody in 10 mL of 
isotonic solution. Tislelizumab has been aseptically filled in a single-use glass vial with a rubber 
stopper and capped by an aluminum flip-off seal cap. 
The contents of the label will be in accordance with all applicable local regulatory requirements. 
The study drug must be kept at the temperature condition as specified on the label. 
Refer to the Pharmacy Manual for details regarding IV administration, accountability, and 
disposal. Please also refer to the Tislelizumab Investigator’s Brochure for other details 
regarding tislelizumab. 
5.1.3. 
Oxaliplatin (Part A and C Only) 
Patients will receive commercially or locally supplied oxaliplatin as part of institutional 
standard of care. 
5.1.4. 
Capecitabine (Part A and C Only) 
Patients will receive commercially or locally supplied capecitabine as part of institutional 
standard of care. 

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5.1.5. 
Leucovorin calcium (Part C Only) 
Patients will receive commercially or locally supplied leucovorin calcium (folinic acid), per 
institutional standard of care.  
5.1.6. 
Fluorouracil (Part C Only) 
Patients will receive commercially or locally supplied fluorouracil as part of institutional 
standard of care. 
5.2. 
Study Drug Administration  
5.2.1. 
Dosing Schedules 
The study treatment regimens for Part A and Part B are given in Table 8 (see also Figure 8, 
Figure 9, and Figure 10). The duration for each cycle is 21 days. 
Table 8:  
Study Treatment Regimens – Part A and B only 
Part 
DKN-01 
Tislelizumab 
Oxaliplatin* 
Capecitabine* 
Part A 
300 mg IV 
D1, D15 
200 mg IV 
D1 
130 mg/m2 IV 
D1  
1000 mg/m2PO BID 
D1-D15 
Part B1 
300 mg IV 
D1, D15 
200 mg IV 
D1 
- 
- 
Part B2 
600 mg IV 
D1, D15 
200 mg IV 
D1 
- 
- 
Abbreviations: BID = twice daily; D = day; IV = intravenously; PO = orally 
* Standard regimen as supported by , or per institutional standard of care. 
 
The study treatment regimens for Part C are given in Table 9. The duration for each cycle is 
21 days (CAPOX; Figure 11) or 14 days (mFOLFOX6; Figure 12). 
Table 9:  
Study Treatment Regimen – Part C only 
The duration for each cycle is based on the chemotherapy regimen: CAPOX is 21 days and mFOLFOX6 
is 14 days. The study regimens are as suggested below or per institutional standard practice: 

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Chemo 
Regimen 
DKN-01 
Tislelizumab 
Oxaliplatin1 
Capecitabine1 
Leucovorin 
calcium1, 6 
Fluorouracil1 
Experimental Group 
CAPOX  
600 mg IV  
D12 
200 mg IV  
D1 q 3 weeks 
130 mg/m2 IV 
D1 
1000 mg/m2 PO 
BID; D1-D153 
- 
- 
mFOLFO
X6 
400 mg IV  
D14 
 
400 mg IV 
D1 q 6 weeks5 
85 mg/m2 IV 
D1 
- 
400 mg/m2 
IV  
D1 
400 mg/m2 IV 
bolus on D1 then 
2400 mg/m2 IV 
continuous 
infusion over 48 
hours D1 and D2  
Control Group 
CAPOX 
- 
200 mg IV  
D1 q 3 weeks 
130 mg/m2 IV 
D1 
1000 mg/m2PO 
BID; D1-D153 
- 
- 
mFOLFO
X6 
- 
400 mg IV 
D1 q 6 weeks5 
85 mg/m2 IV 
D1 
- 
400 mg/m2 
IV  
D1 
400 mg/m2 IV 
bolus on D1 then 
2400 mg/m2 IV 
continuous 
infusion over 48 
hours D1 and D2 
Abbreviations: BID = twice daily; D = day; IV = intravenously; PO = orally; q = every 
1 Standard dosing regimen per institutional standard of care. 
2 For Cycle 1 only, an additional loading dose of DKN-01 (600 mg, IV) will be administered on Day 15. 
3 A total of 28 doses from Day 1 through Day 15. 
4 For Cycle 1 only, an additional loading dose of DKN-01 (400 mg, IV) will be administered on Day 8. 
5 Administered every 6 weeks starting on C1D1 and continuing every third 14-day cycle (e.g., C4D1, C7D1, etc). 
6 If leucovorin is unavailable, 200 mg/m2 levo-leucovorin may be used. Study treatment may be administered without either 
agent if neither are available or per institutional standard of care. 
5.2.1.1. 
DKN-01 
DKN-01 will be administered IV without interruption over a minimum of 30 minutes and up to 
a maximum of 2 hours as per the Schedule of Assessments. Specific instructions for product 
preparation and administration are provided in the Pharmacy Manual. 
5.2.1.2. 
Tislelizumab  
Tislelizumab will be administered as per the Schedule of Assessments through an IV line 
containing a sterile, non-pyrogenic, low-protein-binding 0.2 or 0.22 micron in-line or add-on 
filter. Specific instructions for product preparation and administration are provided in the 
Pharmacy Manual. 
As a routine precaution, following the first 2 infusions of tislelizumab, patients must be 
monitored for at least 60 minutes afterward in an area with resuscitation equipment and 
emergency agents. From Cycle 3 onward, at least a 30-minute monitoring period is required in 
an area with resuscitation equipment and emergency agents. 
The initial infusion (C1D1) will be delivered over 60 minutes; if this is well tolerated, then the 
subsequent infusions may be administered over 30 minutes, which is the shortest time period 
permissible for infusion. Tislelizumab must not be concurrently administered with any other 
drug. 

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5.2.1.3. 
Oxaliplatin – Part A and C only 
Oxaliplatin will be administered IV as per the Schedule of Assessments according to 
institutional standard of care. Standard of care premedication for oxaliplatin will be given prior 
to DKN-01 and tislelizumab for the Part C experimental arm and prior to tislelizumab for the 
Part C control arm.  
5.2.1.4. 
Capecitabine – Part A and C only 
As per the Schedule of Assessments, the patient will administer capecitabine PO twice daily 
(BID) for a total of 28 doses per cycle according to institutional standard of care. Note: 
Capecitabine should be taken after food (within 30 minutes of a meal) with water (morning and 
evening) and at the same time each day (± 60 minutes). 
Further, if a Part A or Part C patient is receiving clinical benefit from treatment with 
capecitabine without evidence of progressive disease and develops a compelling clinical reason 
after completion of Cycle 2 (e.g., unable to swallow pills) to discontinue the oral medication 
he/she may be considered for changing to intravenous 5-FU based therapy, after discussion with 
the Medical Monitor and per institutional standard of care.  
Standard of care premedication for capecitabine will be given prior to study drug as necessary. 
5.2.1.5. 
Leucovorin calcium and Fluorouracil – Part C only 
Leucovorin calcium and fluorouracil will be administered IV as per the Schedule of 
Assessments according to institutional standard of care. Standard of care premedication for 
leucovorin calcium and fluorouracil will be given prior to DKN-01 and tislelizumab for the Part 
C experimental arm and prior to tislelizumab for the Part C control arm.  
5.2.2. 
Order of Administration 
In Part A, the order of IV administration will be DKN-01, tislelizumab, and then oxaliplatin. 
Capecitabine may be taken at any time on Day 1. 
In Part B, DKN-01 will be administered first, followed by tislelizumab. 
In Part C, the order of IV administration in the experimental group will be DKN-01, then 
tislelizumab followed by chemotherapy regimen thereafter.  
• For patients receiving CAPOX, the order of IV administration will be DKN-01, 
tislelizumab, and then oxaliplatin. Capecitabine may be taken at any time on Day 1 
• For patients receiving mFOLFOX6, the order of administration will be DKN-01, 
tislelizumab followed by chemotherapy (oxaliplatin, leucovorin, and fluorouracil will be 
given per institutional SOC guidelines) 
In Part C, the order of IV administration in the control group will be tislelizumab followed by 
chemotherapy regimen thereafter.  
• For patients receiving CAPOX, the order of IV administration will be tislelizumab then 
oxaliplatin. Capecitabine may be taken at any time on Day 1 

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• For patients receiving mFOLFOX6, the order of administration will be tislelizumab 
followed by chemotherapy (oxaliplatin, leucovorin, and fluorouracil will be given per 
institutional SOC guidelines).  
5.2.2.1. 
Dose Delays 
A dose delay is a deviation from prescribed dosing schedule (i.e., the drug is withheld beyond 
visit window). A dose interruption is an interruption of an infusion. 
Every effort should be made to administer the study drug(s) according to the planned dose and 
schedule. In the event of significant toxicities, dosing may be delayed and/or reduced based on 
the guidelines below. Dosing may also be delayed if laboratory parameters shown in Section 
5.2.3 are not met. Reasons for dose modifications or delays, the supportive measures taken, and 
the outcome must be documented in the patient’s chart and recorded in the eCRF. 
The start of a new cycle may be delayed up to 42 days (for toxicities only; a delay may be more 
than 42 days for the management of irAEs up to a maximum of 12 weeks after approval from 
the Medical Monitor) to allow sufficient time for recovery from the previous cycle. Patients 
who do not recover from toxicity within 42 days (except for management of irAEs, which may 
require longer than 42 days) may be discontinued from the study and will undergo end of 
treatment procedures. 
Specific treatment modifications to manage treatment-emergent drug reactions for DKN-01 and 
tislelizumab are described in Appendix 7 and Appendix 8. Specific treatment modifications to 
manage infusion-related reactions for DKN-01 and tislelizumab are described in Appendix 12 
and Appendix 13. Infusion-related or hypersensitivity reactions to capecitabine, oxaliplatin 
leucovorin calcium, or fluorouracil should be managed per institutional standard of care. 
A treatment delay at the start of a cycle (D1) of no more than 7 days, because of holidays, 
weekends, inclement weather, or other justifiable events, will be permitted and not considered 
as a protocol deviation. 
For Part A and Part B: If the administration of study drug(s) can resume within ≤10 days, it 
should be administered in the current cycle. If the study drug needs to be withheld for >10 days, 
it should be omitted from the current cycle and administration should continue at the start of the 
next cycle. 
5.2.2.1.1. DKN-01 Dose Delays  
DKN-01 treatment may be temporarily suspended if the patient experiences a toxicity that is 
considered related to DKN-01 and requires a dose to be withheld (see Appendix 7). 
DKN-01-related toxicities must be resolved to baseline or Grade 1 (whichever is more severe) 
prior to administering the next dose, except for alopecia or ≤Grade 2 fatigue or neuropathy. 
5.2.2.1.2. Tislelizumab Dose Delays  
Tislelizumab treatment may be temporarily suspended if the patient experiences a toxicity that 
is considered related to tislelizumab and requires a dose to be withheld. Tislelizumab treatment 
should resume as soon as possible after the AEs recover to baseline or Grade 1 (whichever is 
more severe) and within 12 weeks after last dose of tislelizumab. If the patient is not able to 

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resume tislelizumab ≤12 weeks after the last dose, continued treatment may be allowed if 
approved by the Medical Monitor.  
5.2.2.1.3. Chemotherapy Dose Delays (Part A and Part C only) 
Chemotherapy-related toxicities must be resolved to baseline or Grade 1 (whichever is more 
severe) prior to administering the next dose, except for alopecia or ≤Grade 2 fatigue or 
neuropathy.  
If chemotherapy-related toxicities warrant a dosing delay, chemotherapy administration may 
restart as soon as is feasible. For example, chemotherapy administration can occur during an 
unscheduled visit and resynchronize with tislelizumab and DKN-01 at subsequent cycle(s), if 
possible. Dosing intervals of subsequent cycles of tislelizumab and DKN-01 may be shortened 
or extended as clinically feasible to allow for resynchronization, but the time between 
2 consecutive doses of tislelizumab should be at least 10 days (Parts A, B, and C-CAPOX 
regimen only) and 28 days (Part C-mFOLFOX6 regimen only) and for DKN-01 should be at 
least 7 days. If clinically appropriate, the Investigator may delay all treatment components up to 
a maximum of 7 days to allow synchronized administration of all agents and realigned dosing of 
treatment cycles according to the original schedule. 
5.2.2.2. 
Dose Adjustments 
5.2.2.2.1. DKN-01 Dose Adjustments 
Once a patient recovers from DKN-01-related toxicities (see Appendix 7) as described in 
Section 5.2.2.1.1 and meets guidelines in Section 5.2.3, dosing may resume based on the 
guidelines in Table 10, Table 11, Table 12, Table 13, Table 14, and Table 15. 
Table 10: 
DKN-01 Dose Adjustments for Parts A and B1 
Toxicity 
Occurrence 
DKN-01 
First1  
• 
Restart at 300 mg after toxicity resolves to ≤Grade 1 or baseline grade (whichever is 
more severe).  
Second  
• 
Restart at reduced dose of 150 mg after toxicity resolves to ≤Grade 1 or baseline 
grade (whichever is more severe).  
Third  
• 
Restart at reduced dose of 75 mg after toxicity resolves to ≤Grade 1 or baseline 
grade (whichever is more severe). Confer with Medical Monitor. 
Fourth 
• 
Discontinue 
If the toxicity is judged to be significant in the opinion of the Investigator or the Investigator does not wish to dose at the 
same dosing level, he/she may contact the Medical Monitor to consider a one dose reduction level with the first occurrence 
of toxicity. 

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Table 11: 
DKN-01 Dose Adjustments for Part B2  
Toxicity 
Occurrence 
DKN-01 
First1  
• 
Restart at 600 mg after toxicity resolves to ≤Grade 1 or baseline grade (whichever is 
more severe).  
Second  
• 
Restart at reduced dose of 300 mg after toxicity resolves to ≤Grade 1 or baseline 
grade (whichever is more severe). 
Third  
• 
Restart at reduced dose of 150 mg after toxicity resolves to ≤Grade 1 or baseline 
grade (whichever is more severe). Confer with Medical Monitor. 
Fourth 
• 
Discontinue 
If the toxicity is judged to be significant in the opinion of the Investigator or the Investigator does not wish to dose at the 
same dosing level, he/she may contact the Medical Monitor to consider a one dose reduction level with the first 
occurrence of toxicity. 
Table 12: 
DKN-01 Dose Adjustments for Part C (experimental arm)  
Toxicity 
Occurrence 
DKN-01 
First1  
• 
Restart at 400 mg or 600 mg (depending upon starting dose) after toxicity resolves 
to ≤Grade 1 or baseline grade (whichever is more severe).  
Second  
• 
Restart at reduced dose of 300 mg after toxicity resolves to ≤Grade 1 or baseline 
grade (whichever is more severe). 
Third  
• 
Restart at reduced dose of 150 mg after toxicity resolves to ≤Grade 1 or baseline 
grade (whichever is more severe). Confer with Medical Monitor. 
Fourth 
• 
Discontinue 
If the toxicity is judged to be significant in the opinion of the Investigator or the Investigator does not wish to dose at the 
same dosing level, he/she may contact the Medical Monitor to consider a one dose reduction level with the first 
occurrence of toxicity. 
Once a patient’s DKN-01 dose has been reduced, no re-escalation to a previously received dose 
is allowed at any time during the study. Intra-patient dose escalation is not permitted at any time 
during the study.  
If, in the opinion of the Investigator, a Part A patient is receiving clinical benefit from treatment 
with the combination of DKN-01 plus tislelizumab plus CAPOX but has a compelling clinical 
reason after completion of Cycle 2 to discontinue oxaliplatin, capecitabine, and/or tislelizumab 
treatment, the patient will be permitted to continue in the study with DKN-01 monotherapy or 
any combination of DKN-01 + other study drugs (e.g., oxaliplatin, capecitabine and/or 
tislelizumab) at the discretion of the treating clinician, after discussion with the Medical 
Monitor.  
If, in the opinion of the Investigator, a Part B patient is receiving clinical benefit from treatment 
with the combination of DKN-01 plus tislelizumab but has a compelling clinical reason after 
completion of Cycle 2 to discontinue tislelizumab treatment, the patient will be permitted to 
continue in the study with DKN-01 monotherapy at the discretion of the treating clinician, after 
discussion with the Medical Monitor.  
If, in the opinion of the Investigator, a Part C (experimental arm only ) patient is receiving 
clinical benefit from treatment with the combination of DKN-01 plus tislelizumab plus 
CAPOX/mFOLFOX6 but has a compelling clinical reason after completion of Cycle 2 to 

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discontinue one or several of the combination agents, e.g., oxaliplatin, capecitabine, leucovorin 
calcium, fluorouracil, DKN-01, and/or tislelizumab treatment, the patient will be permitted to 
continue in the study provided at least one of the agents is continued and no new systemic 
therapies are added at the discretion of the treating clinician, after discussion with the Medical 
Monitor.  
If, in the opinion of the Investigator, a Part C (control arm only) patient is receiving clinical 
benefit from treatment with the combination tislelizumab plus CAPOX/mFOLFOX6 but has a 
compelling clinical reason after completion of Cycle 2 to discontinue one or several of the 
combination agents, e.g., oxaliplatin, capecitabine, leucovorin calcium, fluorouracil, and/or 
tislelizumab treatment, the patient will be permitted to continue in the study provided at least 
one of the agents is continued and no new systemic therapies are added at the discretion of the 
treating clinician, after discussion with the Medical Monitor. 
5.2.2.2.2. Tislelizumab Dose Adjustments 
There will be no dose reduction for tislelizumab in this study. 
If, in the opinion of the Investigator, a Part A patient is receiving clinical benefit from treatment 
with the combination of DKN-01 plus tislelizumab plus chemotherapy regimen (CAPOX) but 
has a compelling clinical reason after completion of Cycle 2 to discontinue oxaliplatin, 
capecitabine, and/or tislelizumab treatment, the patient will be permitted to continue in the 
study with DKN-01 monotherapy or any combination of DKN-01 + other study drugs (e.g., 
oxaliplatin, capecitabine and/or tislelizumab) at the discretion of the treating clinician, after 
discussion with the Medical Monitor.  
If, in the opinion of the Investigator, a Part B patient is receiving clinical benefit from treatment 
with the combination of DKN-01 plus tislelizumab but has a compelling clinical reason after 
completion of Cycle 2 to discontinue tislelizumab treatment, the patient will be permitted to 
continue in the study with DKN-01 monotherapy at the discretion of the treating clinician, after 
discussion with the Medical Monitor. 
If, in the opinion of the Investigator, a Part C (experimental arm only) patient is receiving 
clinical benefit from treatment with the combination of DKN-01 plus tislelizumab plus 
CAPOX/mFOLFOX6 but has a compelling clinical reason after completion of Cycle 2 to 
discontinue one or several of the combination agents, e.g., oxaliplatin, capecitabine, leucovorin 
calcium, fluorouracil, DKN-01, and/or tislelizumab treatment, the patient will be permitted to 
continue in the study provided at least one of the agents is continued and no new systemic 
therapies are added at the discretion of the treating clinician, after discussion with the Medical 
Monitor.  
If, in the opinion of the Investigator, a Part C (control arm only) patient is receiving clinical 
benefit from treatment with the combination tislelizumab plus CAPOX/mFOLFOX6 but has a 
compelling clinical reason after completion of Cycle 2 to discontinue one or several of the 
combination agents, e.g., oxaliplatin, capecitabine, leucovorin calcium, fluorouracil, and/or 
tislelizumab treatment, the patient will be permitted to continue in the study provided at least 
one of the agents is continued and no new systemic therapies are added at the discretion of the 
treating clinician, after discussion with the Medical Monitor.  

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5.2.2.2.3. Chemotherapy Dose Adjustments (Part A and Part C) 
Dose modifications for chemotherapy should be performed per applicable local prescribing 
information and per local practice according to the Investigator’s clinical judgment. 
Recommended dose modifications for key chemotherapy toxicities are outlined in Table 13 and 
Table 14. These serve as guidelines and do not replace Investigator judgment and applicable 
local label recommendations if more stringent. Baseline body weight is used to calculate the 
required chemotherapy doses. Dose modifications are required if the patient’s body weight 
changes by ≥10% from baseline or according to institutional standards. Chemotherapy doses 
should not be modified for any body weight change of ˂ 10%. 
Reduction of one chemotherapy agent and not the other agent is appropriate if, in the opinion of 
the Investigator, the toxicity is clearly related to one of the treatments. If, in the opinion of the 
Investigator, the toxicity is related to the combination of both chemotherapy agents, both drugs 
should be reduced according to recommended dose modifications. 
Study drug-related toxicities must be resolved to baseline or Grade 1 (whichever is more 
severed) prior to administering the next dose, except for alopecia or ≤Grade 2 fatigue or 
neuropathy. 
Table 13: 
Capecitabine Dose Adjustments (Part A and Part C)2 
Toxicity 
Occurrence 
Capecitabine  
First1  
• 
Restart at 1000 mg/m2 after toxicity resolves to ≤Grade 1 or baseline grade (whichever 
is more severe). 
Second  
• 
Restart at reduced dose of 750 mg/m2 after toxicity resolves to ≤Grade 1 or baseline 
grade (whichever is more severe).  
Third  
• 
Restart at reduced dose of 500 mg/m2 after toxicity resolves to ≤Grade 1 or baseline 
grade (whichever is more severe).  
Fourth 
• 
Discontinue 
1If the toxicity is judged to be significant in the opinion of the Investigator or the Investigator does not wish to dose at the 
same dosing level, he/she may contact the Medical Monitor to consider a one dose reduction level with the first 
occurrence of toxicity. 2 dose reductions may be performed per institutional guidelines 
Table 14: 
Oxaliplatin Dose Adjustments (Part A and Part C)2 
Toxicity 
Occurrence 
Oxaliplatin 
First1  
• 
Restart at 130 mg/m2  (CAPOX) or 85 mg/m2 (mFOLFOX6) after toxicity resolves to 
≤Grade 1 or baseline grade (whichever is more severe). 
Second  
• 
Restart at reduced dose of 100 mg/m2 (CAPOX) or 70 mg (mFOLFOX6) after toxicity 
resolves to ≤Grade 1 or baseline grade (whichever is more severe).  
Third  
• 
Restart at reduced dose of 70 mg/m2 (CAPOX) or 55 mg (mFOLFOX6) after toxicity 
resolves to ≤Grade 1 or baseline grade (whichever is more severe).  
1If the toxicity is judged to be significant in the opinion of the Investigator or the Investigator does not wish to dose at the 
same dosing level, he/she may contact the Medical Monitor to consider a one dose reduction level with the first occurrence of 
toxicity. 2 dose reductions may be performed per institutional guidelines 

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Table 15: 
Fluorouracil Dose Adjustments (Part C)2 
Toxicity 
Occurrence 
Fluorouracil 
First1  
• 
Restart at 1200 mg/m2/day after toxicity resolves to ≤Grade 1 or baseline grade 
(whichever is more severe). 
Second  
• 
Restart at reduced dose of 900 mg/m2/day after toxicity resolves to ≤Grade 1 or baseline 
grade (whichever is more severe).  
Third  
• 
Restart at reduced dose of 750 mg/m2/day after toxicity resolves to ≤Grade 1 or baseline 
grade (whichever is more severe).  
1If the toxicity is judged to be significant in the opinion of the Investigator or the Investigator does not wish to dose at the 
same dosing level, he/she may contact the medical Medical Monitor to consider a one dose reduction level with the first 
occurrence of toxicity. 2 dose reductions may be performed per institutional guidelines 
If, in the opinion of the Investigator, a Part A patient is receiving clinical benefit from treatment 
with the combination of DKN-01 plus tislelizumab plus chemotherapy regimen (CAPOX) but 
has a compelling clinical reason after completion of Cycle 2 to discontinue oxaliplatin, 
capecitabine, and/or tislelizumab treatment, the patient will be permitted to continue in the 
study with DKN-01 monotherapy or any combination of DKN-01 + other study drugs (e.g., 
oxaliplatin, capecitabine and/or tislelizumab) at the discretion of the treating clinician, after 
discussion with the Medical Monitor.  
If, in the opinion of the Investigator, a Part B patient is receiving clinical benefit from treatment 
with the combination of DKN-01 plus tislelizumab but has a compelling clinical reason after 
completion of Cycle 2 to discontinue tislelizumab treatment, the patient will be permitted to 
continue in the study with DKN-01 monotherapy at the discretion of the treating clinician, after 
discussion with the Medical Monitor. 
If, in the opinion of the Investigator, a Part C (experimental arm only) patient is receiving 
clinical benefit from treatment with the combination of DKN-01 plus tislelizumab plus 
CAPOX/ mFOLFOX6 but has a compelling clinical reason after completion of Cycle 2 to 
discontinue one or several of the combination agents, e.g., oxaliplatin, capecitabine, leucovorin 
calcium, fluorouracil, DKN-01, and/or tislelizumab treatment, the patient will be permitted to 
continue in the study provided at least one of the agents is continued and no new systemic 
therapies are added at the discretion of the treating clinician, after discussion with the Medical 
Monitor.  
If, in the opinion of the Investigator, a Part C (control arm only) patient is receiving clinical 
benefit from treatment with the combination tislelizumab plus CAPOX/mFOLFOX6 but has a 
compelling clinical reason after completion of Cycle 2 to discontinue one or several of the 
combination agents, e.g., oxaliplatin, capecitabine, leucovorin calcium, fluorouracil, and/or 
tislelizumab treatment, the patient will be permitted to continue in the study provided at least 
one of the agents is continued and no new systemic therapies are added at the discretion of the 
treating clinician, after discussion with the Medical Monitor.  
Further, if a Part A or C (CAPOX arm) patient is receiving clinical benefit from treatment with 
capecitabine without evidence of progressive disease and develops a compelling clinical reason 
after completion of Cycle 2 (e.g., unable to swallow pills) to discontinue the oral medication 
he/she may be considered for changing to intravenous 5-FU based therapy, after discussion with 
the Medical Monitor and per institutional standard of care.  

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5.2.3. 
Criteria for Retreatment 
5.2.3.1. 
Criteria for Initiation of a New Treatment Cycle  
Prior to initiating a new cycle including Cycle 1, patients must meet the following criteria:  
• ANC resolved to baseline grade or ≤Grade 1 (≥1.5 × 109/L) 
• Part A: Platelet count ≥100 × 109/L 
• Part B: Platelet count ≥75 × 109/L 
• Part C:  
o Patients receiving chemotherapy during screening are permitted to dose on Cycle 
1 Day 1 and subsequent cycles (CxD1) with a platelet count of  ≥75 × 109/L 
o Patients not receiving chemotherapy during screening are permitted to dose at 
Cycle 1 Day 1 with a platelet count of  ≥100 × 109/L. Retreatment is permitted in 
subsequent cycles (CxD1) with a platelet count of  ≥75 × 109/L 
• Creatinine clearance >30 ml/min  
• Liver-associated biochemical abnormalities resolved to ≤Grade 1 or baseline grade 
• Any other drug-related AEs that may have occurred resolved to ≤Grade 1 severity or 
baseline grade except for alopecia or ≤Grade 2 fatigue or neuropathy. 
If these conditions are not met on D1 of a new cycle, the patient will be evaluated weekly, and a 
new cycle of treatment will not be initiated until the toxicity has resolved as described above.  
5.2.3.2. 
Criteria for DKN-01 Treatment on Day 8 or Day 15 of a Treatment Cycle  
Treatment may be administered on D8 or D15 for patients meeting the following criteria:  
• ANC ≥1.0 × 109/L 
• Platelet count ≥75 × 109/L 
• Liver-associated biochemical abnormalities resolved to ≤Grade 1 or baseline grade 
• Any other drug-related AEs that may have occurred resolved to ≤Grade 1 severity or 
baseline grade except for alopecia or ≤Grade 2 fatigue or neuropathy. 
5.3. 
Prior and Concomitant Therapy 
Most concomitant medications and therapies deemed necessary and in keeping with local 
standards of medical care at the discretion of the Investigator for supportive care (e.g., 
antiemetics, antidiarrheals, blood components, bisphosphonates, growth factor support) and in a 
patient’s interest are allowed. Opiates and other medication required for palliative management 
of patients are allowed. Patients must notify the Investigator of all concurrent medications used 
during the study. 
Supportive care use of transfusion for symptomatic anemia or hemoglobin <8 g/dL and of 
colony stimulating factors for neutropenia is encouraged per established guidelines. 

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5.3.1. 
Systemic Corticosteroids 
Systemic corticosteroids given for the control of irAEs must be tapered gradually (see 
Appendix 8) and be at non-immunosuppressive doses (≤10 mg/day of prednisone or equivalent) 
before the next tislelizumab administration. The short-term use of steroids as prophylactic 
treatments (e.g., patients with contrast allergies to diagnostic imaging contrast dyes) is 
permitted. 
5.3.2. 
Radiation Therapy 
Palliative (limited-field) radiation therapy is permitted, but only for pain control or prophylaxis 
of bone fracture to sites of bone disease present at baseline provided the following criteria are 
met: 
• Repeat imaging demonstrates no new sites of bone metastases 
• The lesion being considered for palliative radiation is not a target lesion for RECIST 
v1.1 
• The case is discussed with the Medical Monitor, and the Medical Monitor agrees that 
the conditions required to receive palliative radiation are met. 
Additionally, palliative radiation or other focally ablative therapy for other non-target sites of 
the disease is permitted if clinically indicated per Investigators’ discretion. The Medical 
Monitor should be informed of the on-study radiotherapy. These patients should have a tumor 
assessment of the lesion(s) before receiving the radiotherapy in order to rule out progression of 
disease. 
Administration of palliative radiation therapy will be considered progression for the purposes of 
determining PFS. 
It is not required to withhold study drugs tislelizumab or DKN-01 treatment during palliative 
radiotherapy. 
5.3.3. 
Prohibited Concomitant Medications/Procedures 
Live vaccines within 28 days before first dose of study drug and within 60 days after the last 
dose of study drug(s) are prohibited. 
The following medications are prohibited during Screening and through the End-of-Treatment 
visit: 
• Any concurrent anticancer therapy, including chemotherapy (except Part C 1 cycle 
allowed during screening), hormonal therapy, immunotherapy, standard anticancer 
agents, or investigational anticancer agents 
• Herbal remedies for the treatment of cancer or patent medicines with approval from 
the local health authority for use as anticancer treatment (regardless of cancer type) 
• Herbal remedies with immune-stimulating properties (e.g., mistletoe extract) or that 
are known to potentially interfere with liver or other major organ functions (e.g., 
hypericin). 

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There are medications prohibited depending on the chemotherapy regimen that is dosed (Part A 
and C only). Please refer to the package insert for each approved chemotherapy agent used for 
these guidelines. 
Patients must notify the Investigator of all herbal remedies used during the study. 
5.3.4. 
Restricted Concomitant Medications/Procedures 
The following medications are restricted during the study: 
• Immunosuppressive agents (except to treat a drug-related AE) 
• Systemic corticosteroids >10 mg daily (prednisone or equivalent), except to treat or 
control a drug related AE (per protocol) or for short-term use as prophylactic 
treatment 
• Abuse of alcohol or other drugs during the study 
• Use of potentially hepatotoxic drugs in patients with impaired hepatic function 
should be carefully monitored 
• Radiation therapy, except for palliative radiation therapy described in Section 5.3.2. 
There are medications prohibited depending on the chemotherapy regimen that is dosed (Part A 
and C only). Please refer to the package insert for each approved chemotherapy agent used for 
these guidelines. 
5.4. 
Blinding 
This is an open-label study; no blinding methods will be employed. 
5.5. 
Randomization 
For Part C of the study, patients will be assigned to receive either DKN-01 in combination with 
tislelizumab and chemotherapy regimen (CAPOX or mFOLFOX6) or tislelizumab in 
combination with chemotherapy regimen (CAPOX or mFOLFOX6) using a central stratified 
block randomization scheme, with the following stratification factors: 
• DKK1 RNAscope TPS (≥20% vs <20%)  
• PD-L1 immunohistochemistry CPS (≥5 vs <5). 
Randomization may occur up to 3 calendar days prior to C1D1. The EDC (Electronic Data 
Capture) system will be used to assign patients to either the experimental group or the control 
group in lieu of a separate IRT (Interactive Response Technology) system. Detailed instructions 
for assigning treatment will be provided in the eCRF completion guidelines. The randomization 
block size will be defined in the EDC system.  
5.6. 
Assessment of Treatment Compliance 
All study drug (except capecitabine; Part A and Part C) will be administered IV at the 
investigational site, under the direction of the Investigator. As a result, a patient’s compliance 
with study drug administration is ensured. Any deviation(s) from the prescribed dosage regimen 
or problems with administering the IV infusion should be recorded in the eCRF.  

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Patients should attend scheduled clinic visits and must comply with study criteria under their 
control. 
5.6.1. 
Study Treatment Diary 
The patient will be requested to maintain a dosing diary of each dose of capecitabine (Part A 
and Part C only). The dosing diary will be returned and reviewed by the site staff at each clinic 
visit.  

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6. 
STUDY ASSESSMENTS AND PROCEDURES 
A table of scheduled study assessments is provided in Appendix 1. Patients will be closely 
monitored for safety and tolerability throughout the study. All assessments must be performed 
and documented in the medical record for each patient. 
Dosing will occur only if the clinical assessment and local laboratory test values (that must be 
available before any dosing) have been reviewed and found to be acceptable per protocol 
guidelines (Section 5.2.3). 
6.1. 
General Considerations 
Study procedures and their timing are summarized in the Schedule of Activities (Appendix 1). 
Protocol waivers or exemptions are not allowed. 
Immediate safety concerns should be discussed with the Sponsor immediately upon occurrence 
or awareness to determine if the patient should continue or discontinue study intervention. 
Adherence to the study design requirements, including those specified in the Schedule of 
Activities, is essential and required for study conduct. 
All Screening evaluations must be completed and reviewed to confirm that potential patients 
meet all eligibility criteria. The Investigator will maintain a screening log to record details of all 
patients screened and to confirm eligibility or record reasons for screening failure, as applicable. 
A complete description of the study is to be presented to each potential study patient. Signed 
and dated informed consent is to be obtained before any study-specific procedures are 
performed. Results of standard-of-care tests or examinations performed prior to obtaining 
informed consent and <28 days prior to enrollment (C1D1) may be used for the purposes of 
screening rather than repeating the standard-of-care tests. 
Procedures conducted as part of the patient’s routine clinical management (e.g., blood count) 
and obtained before signing of the ICF may be utilized for screening or baseline purposes 
provided the procedures met the protocol-specified criteria and were performed within the time 
frame defined in the Schedule of Activities (Appendix 1). 
Only necessary and the least invasive assessments are included. Where applicable, patients must 
be warned that they may experience pain or discomfort. 
6.1.1. 
Visit Windows 
All visits must occur within ± 3 calendar days from the scheduled date, unless otherwise noted 
(see Appendix 1). All assessments will be performed on the day of the specified visit unless an 
acceptable time window is specified. Assessments scheduled on the day of study treatment 
administration (Day 1) of each cycle should be performed prior to study treatment infusion/dose 
unless otherwise noted. Laboratory results are required to be reviewed prior to dosing. 
If the timing of a protocol-mandated study visit coincides with a holiday, weekend, or other 
justifiable event, the visit should be scheduled on the nearest feasible date (the visit window is 
provided in Appendix 1), with subsequent visits conducted according to the planned schedule 
from the preceding cycle. Note: tumor imaging should be conducted every 6 weeks based on the 

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date of C1D1 until week 24 where imaging is then conducted every 9 weeks on the same 
schedule. 
6.1.2. 
Unscheduled Visits 
Unscheduled visits may be performed at any time at the patient’s or the Investigator’s request 
and may include vital signs/focused physical examination; ECG; ECOG performance status; AE 
review; concomitant medications and procedures review; radiographic assessments; disease 
related constitutional symptoms; and laboratory and biomarker assessments (see Appendix 1). 
The date and reason for the unscheduled visit must be recorded in the source documentation. 
If an unscheduled visit is necessary to assess toxicity or for suspected disease progression, then 
diagnostic tests may be performed based on the Investigator assessment as appropriate, and the 
results of these tests should be entered on the unscheduled visit eCRF. 
6.2. 
Screening and Eligibility 
6.2.1. 
Informed Consent and Screening Log 
Voluntary, written informed consent for participation in the study must be obtained before 
performing any study-specific procedures. Informed consent forms for all patients, including 
those who fail screening, will be maintained at the study site. Results of standard-of-care tests 
or examinations performed prior to obtaining informed consent and <28 days prior to 
enrollment (C1D1) may be used for the purposes of screening rather than repeating the 
standard-of-care tests. 
Note: To avoid unnecessary delays which could impact patient care, during the Screening 
Period patients who in the opinion of the Investigator are unable to wait more than 2 weeks to 
start treatment, may receive one cycle of chemotherapy (CAPOX or mFOLFOX6) prior to 
randomization while awaiting biomarker results. Patients meeting these requirements should be 
discussed with the Medical Monitor. 
Once DKK1 and PD-L1 results from the central lab are received and the patient has been 
confirmed to meet all other eligibility requirements, the patient will be randomized to receive 
either DKN-01 in combination with tislelizumab and chemotherapy (CAPOX or mFOLFOX6) 
or tislelizumab in combination with chemotherapy (CAPOX or mFOLFOX6). The 
chemotherapy regimen administered during Screening must be equivalent to that following 
randomization.  
The inclusion and exclusion criteria will be reviewed during the Screening Period as 
assessments are performed to confirm patient eligibility for the study. The criteria will be 
reviewed prior to administration of the first dose of study drug on C1D1 to confirm continued 
treatment eligibility. The Investigator will maintain a screening log to record details of all 
patients screened and to confirm eligibility or record reasons for screening failure, as applicable. 
6.2.2. 
Demographics, Medical History, and Disease History 
Demographic data and medical and disease histories will be obtained for all patients during the 
Screening Period. Demographic data to be recorded in the source document/eCRF includes sex, 
race/ethnic origin, and year of birth. Information on significant medical and surgical history 

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including dates, outcome, and if these are ongoing or currently treated will be recorded. The 
date of original cancer diagnosis will be recorded along with any known cancer genomics 
profile results and previous treatments, including chemotherapy, radiation therapy, surgery 
(including paracenteses), and use of blood products, including red cell and platelet transfusions 
and growth factors, within the previous 3 months. In addition, all other medications taken 
within 30 days of the initial Screening visit will be recorded.  
Any clinically significant findings on screening assessments (physical examination, vital signs, 
ECG) prior to first dose of study treatment will be recorded in medical history. 
The medical history will be reviewed prior to dosing on C1D1 to assess continued treatment 
eligibility and adherence to final inclusion/exclusion criteria. This recent medical history 
includes a review for changes from Screening as well as a review of the patient’s recent 
medication use to assess if any changes have occurred since the previous study visit. 
6.2.3. 
Prior and Concomitant Medications/Procedures Review 
A review of concomitant medications and procedures will be conducted at each study visit. Any 
medications taken by study patients or concomitant procedures (e.g., transfusions, radiation, 
surgery, or other palliative care) are to be recorded in the eCRF and reviewed for compliance 
with protocol requirements.  
6.3. 
Safety Assessments 
Refer to Section 7 for additional details on safety monitoring, including AE reporting. 
6.3.1. 
Physical Examination 
A complete physical examination (general appearance, head/ears/eyes/nose/throat, lungs/chest, 
heart, abdomen, lymph nodes, musculoskeletal, extremities, and neurological examination) will 
be conducted at the time points designated in Appendix 1. During Screening, the physical 
examination is to include measurement of height. 
Abbreviated (i.e., symptom-directed) physical examinations will be conducted at the time points 
designated in Appendix 1 to address any complaints or concerns verbalized by the patient at all 
other study visits. 
Any clinically significant abnormalities following the first dose of study treatment should be 
documented as AEs. 
6.3.2. 
Vital Signs and Weight 
Vital signs are to be measured at the time points designated in Appendix 1. Vital signs to be 
measured include systolic and diastolic blood pressure (mmHg; measured in the same arm), 
temperature (°C), pulse (bpm), and respiration rate (breaths/minute). 
Weight will be measured at Screening, on Day 1 of each treatment cycle, and at the end-of-
treatment visit. Body surface area (BSA) is to be calculated on Day 1 of each treatment cycle 
using the weight from that cycle and the Screening height measurement. 
Any clinically significant abnormalities following the first dose of study treatment should be 
documented as AEs. 

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6.3.3. 
Electrocardiograms 
A 12-lead ECG will be obtained at the time points designated in Appendix 1. Additional ECGs 
may be obtained as clinically warranted and judged by the Investigator.  
Patients must be supine for approximately 5 to 10 minutes before ECG collection and remain 
supine but awake during ECG collection.  
ECGs will be interpreted by a qualified physician (the Investigator or qualified designee) at the 
site as soon after the time of ECG collection as possible, and ideally while the patient is still 
present, to determine whether the patient meets entry criteria at the relevant visit(s) and for 
immediate patient management, should any clinically relevant findings be identified.  
If a clinically significant quantitative or qualitative change from baseline is identified after the 
patient signs the informed consent, the Investigator will assess the patient for symptoms (for 
example, palpitations, near syncope, syncope) to determine whether the patient can continue in 
the study. The Investigator or qualified designee is responsible for determining if any change in 
patient management is needed and must document his/her review of the ECG printed at the time 
of evaluation. 
The machine-read ECG intervals and heart rate may be used for data analysis and report writing 
purposes.  
Any clinically significant abnormalities following the first dose of study treatment should be 
documented as AEs. 
6.3.4. 
Eastern Cooperative Oncology Group Performance Status 
Eastern Cooperative Oncology Group Performance Status (Oken, Creech et al. 1982) will be 
determined at the time points designated in Appendix 1.  
6.3.5. 
Safety Laboratory Evaluations 
Routine clinical laboratory evaluations will be performed locally by a certified laboratory 
selected for the study (see Appendix 2). Prior to starting the study, the Investigator will provide 
copies of all laboratory certifications and normal ranges for all laboratory parameters to be 
assessed by the local laboratory. 
Refer to Section 5.2.3 for laboratory criteria required to initiate a new treatment cycle and for 
subsequent study drug doses within a cycle. 
Clinical laboratory evaluations are to be performed at the time points designated in Appendix 1. 
Final clinical laboratories are to be performed at the safety follow-up visit. 
All clinically significant laboratory abnormalities noted on testing will be followed up by repeat 
testing and further investigated according to the judgment of the Investigator. Any clinically 
significant abnormalities should be documented as AEs. 
The Investigator must review all the patient’s laboratory reports in a timely manner. 
Investigators must document their review of each laboratory report and must assess whether or 
not any abnormal test results are clinically significant. The Investigator must complete an 
appropriate AE form for any abnormal test results that are identified as clinically significant. 

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6.3.6. 
Ophthalmic Examinations (Korea only) 
Eye examination, visual acuity test, and optical coherence tomography (or equivalent diagnostic 
test) will be assessed for patients enrolled in the Republic of Korea at the timepoints specified in 
Appendix 1. 
6.3.7. 
Pulmonary Function Tests (Korea only) 
For those patients with radiation pneumonitis enrolled in the Republic of Korea, pulmonary 
function tests are to be performed at the timepoints specified in Appendix 1. 
6.3.8. 
Thyroid and Pancreatic Tests (Korea only) 
Free (FT3) triiodothyronine, free (FT4) thyroxine, amylase and lipase tests will be assessed for 
patients enrolled in the Republic of Korea at the timepoints specified in Appendix 1. 
6.4. 
Tumor Response Evaluations 
Tumor imaging will be performed within 28 days (35 days for Part C) before the first dose of 
study drug. Results of standard-of-care tests or examinations performed prior to obtaining 
informed consent and ≤28 days prior to first dose may be used for the purposes of screening 
rather than repeating the standard-of-care tests. During the study, tumor imaging will be 
performed every 6 weeks (± 7 days) from C1D1 for the first 24 weeks, and then every 9 weeks 
(± 7 days) after 24 weeks based on RECIST v1.1 (Appendix 4). If a tumor assessment is missed 
or conducted outside of the specified assessment window, all subsequent scans should be 
conducted on the planned schedule. 
Screening assessments and each subsequent assessment of the tumor must include computed 
tomography (CT) scans of chest, abdomen, and pelvis with oral/IV contrast, unless 
contraindicated. Other known or suspected sites of disease must be included in the imaging 
assessments (neck, brain, etc.). See below if patient has contraindication to CT contrast media. 
All measurable and evaluable lesions should be assessed and documented at the Screening Visit 
and reassessed at each subsequent tumor evaluation. The same radiographic procedure used to 
assess disease sites at Screening is required to be used throughout the study (e.g., the same 
contrast protocol for CT scans).  
• Imaging of the brain (preferably MRI) at baseline is required for all screened 
patients. Screening evaluations will be performed within 28 days (35 days for Part 
C) prior to first dose 
• If a patient is known to have a contraindication to CT contrast media or develops a 
contraindication during the study, a non-contrast CT of the chest plus a contrast 
enhanced MRI (if possible) of abdomen and pelvis should be performed 
• If a CT scan for tumor assessment is performed on a positron emission tomography 
(PET)/CT scanner, the CT acquisition must be consistent with the standards of a 
diagnostic CT scan 
• Bone scans (Technetium-99m [Tc-99m]) or PET should be performed at Screening 
if clinically indicated. If bone metastases are present at Screening and cannot be seen 

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on CT or MRI scans, Tc-99m or PET bone scans should be repeated when a CR is 
suspected in target lesion or when progression in bone is suspected 
• CT scans of the neck or extremities should be performed at Screening only if 
clinically indicated and should be followed throughout the study if there is evidence 
of metastatic disease in these regions at Screening 
• At the Investigator’s discretion, other methods of assessment of target lesion and 
nontarget lesions per RECIST v1.1 may be used. 
After first documentation of response (CR or PR), confirmation of tumor response should occur 
at a minimum of 4 weeks after the first response or at the next scheduled assessment time point. 
Radiological images will be read locally and then sent to a central imaging vendor (Part C 
only). The Sponsor may have a central imaging vendor perform an independent evaluation of 
some or all of the radiological images in Part C. More information can be found in the Imaging 
Manual. 
For immune therapies such as tislelizumab, pseudo progression may occur due to immune cell 
infiltration and other mechanisms leading to an apparent increase of existing tumor masses or 
appearance of new tumor lesions. Also, some patients may benefit from additional immune 
therapies despite evidence of disease progression. The following criteria must be met in order to 
treat patients with suspected pseudo progression or confirmed evidence of disease progression: 
• Absence of clinical symptoms and signs of disease progression (including clinically 
significantly worsening of laboratory values) 
• Stable ECOG performance status ≤1 
• Absence of rapid progression of disease or of progressive tumor at critical 
anatomical sites (e.g., cord compression) that requires urgent alternative medical 
intervention 
• Investigators must obtain written informed consent for treatment beyond radiologic 
disease progression and inform patients that this practice is not considered standard 
in the treatment of cancer. Patients must be informed that they may be forgoing 
treatment that has shown benefit by continuing treatment beyond progression 
• The decision to continue study drug(s) beyond initial Investigator-assessed 
progression must be agreed with the Sponsor Medical Monitor and documented in 
the study records. 
Tumor assessment should continue as planned in patients receiving study drug(s) beyond initial 
Investigator-assessed progression. Tumor assessment in such patients should continue until 
study treatment discontinuation. 
Patients who discontinue study treatment early for reasons other than disease progression (e.g., 
toxicity) will continue to undergo tumor assessments following the original plan until the 
patient begins a subsequent anticancer treatment, experiences disease progression, withdraws 
consent, is lost to follow-up, dies, or until the study terminates, whichever occurs first. 

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Tumor assessments are required to be performed on schedule regardless of whether study 
treatment has been administered or held. That is, they should not be adjusted for delays in 
cycles. 
Tumor response and progression will also be assessed using the Immune-related Response 
Criteria, 2017 (iRECIST) for any patients continuing treatment after the initial assessment of 
progressive disease using RECIST 1.1(Seymour, Bogaerts et al. 2017). 
Patients should have the same radiographic imaging modality used throughout the study (at 
baseline and at subsequent assessments) in order to provide uniformity to radiographic 
assessments. 
6.5. 
Post-Treatment Follow-up and Mortality Assessments 
After completion of the EOT visit, patients without radiographically documented PD will 
continue to be followed up in the PD Follow-up Period until radiographically documented PD. 
During this PD Follow-up Period, efficacy assessments for disease response and PD per 
RECIST v1.1 will be performed every 12 weeks (± 14 days) (see Appendix 1). After 
discontinuation of treatment and documentation of PD, all patients will be followed in the 
Survival Follow-up Period for survival until death, withdrawal of consent, loss to follow-up, or 
closure of the study by the Sponsor. Survival follow-up will occur 4 times per year (every 
3 months [± 14 days]) after the 30 days post treatment discontinuation visit or end of PD 
follow-up phase, as applicable, and may be conducted via telephone or office visit. During 
survival follow-up, the following information will be collected: survival and subsequent 
anticancer therapies. If a female patient is of childbearing potential, she will be followed 
monthly with a urine pregnancy test up to 6 months following the last dose of study drug. This 
testing can occur at with a primary care physician and documentation made available to the 
study team. Male subjects will be asked during the PD and/or survival follow up period, if their 
female partners have experienced a pregnancy. 
6.6. 
Pharmacokinetics, Pharmacodynamics, and Biomarker Analyses 
Blood samples are to be collected for PK, pharmacodynamics, and scientific analyses, as 
indicated in the following subsections and at the time points designated in Appendix 1. After 
processing of the samples for the protocol-specified assays, any remaining biological material 
(whole blood, serum, plasma) is to be stored for future scientific analyses, as deemed 
appropriate.  
Details of sample collection and processing can be found in the Laboratory Manual. 
6.6.1. 
Blood Sample Collection for Biomarker (Proteome) Analysis 
Serum and plasma blood samples will be collected for a scientific biomarker (proteome) 
analysis at the time points designated in Appendix 1. 
6.6.2. 
Blood Sample Collection for DKK1 
Blood samples will be collected for determination of total DKK1 (includes DKK1/DKN-01 
complex) in serum at the time points designated in Appendix 1. Free serum DKK1 levels may 
be estimated.  

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Serum levels of DKK1 will be measured using a validated enzyme-linked immunosorbent 
assay, designed to perform in the presence of DKN-01.  
6.6.3. 
Circulating Tumor DNA 
Blood samples for circulating tumor DNA (ctDNA) analysis will be collected pre-dose at 
baseline and at time of relapse (see Appendix 1). Change from baseline in ctDNA post-
treatment may be determined.  
6.6.4. 
Pharmacokinetic Samples 
Blood samples will be collected for the assessment of serum DKN-01 and tislelizumab 
concentrations at the time points designated in Appendix 1. The actual date and time (24-hour 
clock time) of each sampling will be recorded.  
Serum concentrations of DKN-01 will be assayed using a validated method at a laboratory 
designated by the Sponsor.  
Serum samples will be assayed for tislelizumab concentration with use of a validated 
immunoassay. 
Prior to analysis, the samples will be stored at a facility designated by the Sponsor. 
Bioanalytical samples collected to measure investigational product concentrations will be 
retained for a maximum of 15 years following study closure. 
Any remaining serum from the samples collected for PK may be pooled and used for scientific 
analysis work, as deemed appropriate.  
6.6.5. 
Antidrug Antibodies 
DKN-01 or tislelizumab may elicit an immune response. Patients with signs of any potential 
immune response to DKN-01 or tislelizumab will be closely monitored. Validated screening 
and confirmatory assays will be employed to detect ADAs at multiple time points throughout 
the study (see Appendix 1). The immunogenicity evaluation will utilize a risk-based 
immunogenicity strategy (Rosenberg and Worobec 2004, Worobec and Rosenberg 2004, Koren, 
Smith et al. 2008) to characterize ADA responses to DKN-01 or tislelizumab in support of the 
clinical development program. This tiered strategy will include an assessment of whether ADA 
responses correlate with relevant clinical endpoints. Implementation of ADA characterization 
assays will depend on the safety profile and clinical immunogenicity data. 
The following assessment will be performed at a central laboratory: 
• ADA assays: serum samples will be tested for the presence of ADAs to DKN-01 or 
tislelizumab using a validated immunoassay. 
Shipping, storage, and handling of samples for the assessment of DKN-01 or tislelizumab ADA 
assays will be managed through a central laboratory. Instruction manuals and supply kits will be 
provided for all central laboratory assessments. 
For patients who experience an infusion-related reaction to DKN-01 (see Appendix 12), all 
attempts should be made to obtain blood samples for determination of anti-DKN-01 antibody 
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possible, at the resolution of the event, and 30 days following the event or just prior to the start 
of new therapy, whichever comes first. In addition, these samples may be used for 
determination of pharmacodynamic markers. 
If a patient has known positive ADA (to DKN-01 or tislelizumab) at the EOT visit, he or she 
should have repeat testing, where feasible, performed in the PD Follow-up Period and/or 
Survival Follow-up Period until the patient is no longer positive. 
6.6.6. 
Tumor Biopsy Samples 
A tumor sample (fresh biopsy [preferred] or archived specimen) will be obtained from all 
patients during Pre-screening (Part B only) and Screening and will be sent to the Sponsor-
designated central laboratory.  
For Part B, the biopsy sample (fresh biopsy [preferred] or archival) collected during the Pre-
Screening period will be used to confirm elevated DKK1 mRNA levels required to meet 
eligibility criteria for enrollment. A fresh biopsy will be collected during the Screening period 
from patients who did not undergo a biopsy during the Pre-screening period for evaluation of 
DKK1 mRNA levels (unless it is clinically contraindicated per Investigator and after 
consultation with the Medical Monitor) for a retrospective DKK1 mRNA analysis.  
For all Part A patients and Part B patients with fresh biopsies, the patient’s biopsy sample 
obtained during the Screening Period will be sent to the Sponsor-designated central laboratory 
for retrospective evaluation of DKK1 expression.  
All DKK1 testing will be conducted with a proprietary CISH assay using RNAscope technology 
at Flagship Biosciences, Inc. Westminster, CO, a CAP-accredited and Clinical Laboratory 
Improvement Amendments (CLIA)-certified laboratory. For Part C, PD-L1 expression will also 
be conducted by Flagship Biosciences. If the central lab is unable to result a PD-L1 CPS score, 
historical CPS data can be used provided it was generated using either the 22C3 pharmDx, 28-8 
pharmDx or SP263 assays. 
For both Parts A and B, PD-L1 expression will be retrospectively assessed and if sufficient 
tumor biopsy tissue is available. In Part A, B, and C, scientific analysis, including microsatellite 
status (e.g., microsatellite stable MSS, microsatellite instability-low [MSI-L] or microsatellite 
instability-high [MSI-H]), genomic profiling, RNA profiling (e.g., RNA-Seq), 
immunohistology, Epstein Barr virus (EBV), infiltrating immune cells by IHC, and additional 
IHC analyses may be performed.  
For Part C patients, DKK1 testing and PD-L1 expression will be prospectively analyzed to 
permit stratification prior to randomization. DKK1 expression will be assessed using a Tumor 
Percentage Score (TPS). TPS has demonstrated significant correlation with H-score in 
retrospective analysis.  
For Part C patients, an on-treatment biopsy is required if clinically feasible at Day 21 (+ 7 
days). If possible, this should come from the same lesion used for the screening analysis. If the 
original lesion is no longer measurable, then a biopsy from another lesion is acceptable. 
Additional tumor tissue collected at any time during the study per standard of care may be 
submitted to the central laboratory for evaluation. Any on-treatment biopsy tissue will be sent to 
the Sponsor-designated central laboratory for evaluation of DKK1 expression and other 
biomarkers of interest.  

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An additional biopsy to evaluate the effects of treatment on the tumor tissue may be collected at 
any time during the study if a repeat biopsy is required clinically and the patient consents to the 
biopsy. 
Shipping, storage, and handling of archival tumor, fresh tumor, and leftover tumor tissue for the 
assessment of tumor biomarkers will be managed through a central laboratory. Refer to the 
laboratory manual for details of sample handling. 
The samples will be coded with the patient number and stored for up to a maximum 15 years 
after the last patient visit for the study at a facility selected by the Sponsor. The samples and any 
data generated from them can only be linked back to the patient by Investigator site personnel. 
The duration allows the Sponsor to respond to regulatory requests related to the study drug. 
Samples will be destroyed according to a process consistent with local regulation. 
6.6.7. 
Biomarkers 
Blood samples for scientific analysis relevant to DKN-01 and/or the study indication will be 
collected at the time points specified in Appendix 1. 
Samples may be stored for a maximum of 15 years following last patient visit for the study at a 
facility selected by the Sponsor. 
Shipping, storage, and handling of blood samples for the assessment of biomarkers will be 
managed through a central laboratory. Refer to the laboratory manual for details of sample 
handling. 

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7. 
SAFETY MONITORING AND REPORTING 
The Investigator is responsible for the monitoring and documentation of events that meet the 
criteria and definition of an AE or SAE as provided in this protocol. 
7.1. 
Risks Associated with Study Drug 
7.1.1. 
Risks Associated with Tislelizumab 
Tislelizumab is an investigational agent that is currently in clinical development. The following 
recommendation is based on results from nonclinical and clinical studies with tislelizumab and 
published data on other molecules within the same biologic class. 
The PD-L1/PD-1 pathway is involved in peripheral immune tolerance; therefore, such therapy 
may increase the risk of irAEs, specifically the induction or enhancement of autoimmune 
conditions.  
Although most irAEs observed with immunomodulatory agents have been mild and self-
limiting, such events should be recognized early and treated promptly to avoid potential major 
complications. Suggested evaluation and management guidelines for suspected irAEs are 
provided in Appendix 8. 
7.1.2. 
Risks Associated with DKN-01 
DKN-01 is a potent, humanized monoclonal antibody that is currently in clinical development. 
The following recommendation is based on results from nonclinical and clinical studies with 
DKN-01 and published data on other molecules within the same biologic class. 
Specific treatment modifications to manage treatment-emergent drug reactions for DKN-01 and 
tislelizumab are described in Appendix 7 and Appendix 8. Specific treatment modifications to 
manage infusion-related reactions for DKN-01 and tislelizumab are described in Appendix 12 
and Appendix 13.  
Refer to Section 1.6 for a benefit-risk assessment. 
7.2. 
General Plan to Manage Safety Concerns  
7.2.1. 
Eligibility Criteria 
Eligibility criteria were selected to guard the safety of patients in this study. Results from the 
nonclinical toxicology studies and clinical data with tislelizumab, as well as the 
nonclinical/clinical data from other PD-L1/PD-1 inhibitors, were considered. Specifically, 
patients at risk for study-emergent active autoimmune diseases or with a history of autoimmune 
diseases that may relapse, patients who have undergone allogeneic stem cell or organ 
transplantation, and patients who have received a live vaccine within 28 days before first dose 
of study drug are excluded from the study. Patients with contraindications for DKN-01, 
capecitabine, oxaliplatin, or fluorouracil treatment are also excluded from the study (see 
Section 4 for the full list of exclusion criteria). 

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7.2.2. 
Safety Monitoring Plan 
Safety will be evaluated in this study through the monitoring of all AEs, defined and graded 
according to NCI-CTCAE v5.0. Patients will be evaluated clinically and with standard 
laboratory tests at regular intervals during their participation in this study. Safety evaluations 
will consist of medical interviews, recording of AEs (see Table 16), physical examinations, 
laboratory measurements (hematology, chemistry, etc.), and other assessments including those 
listed in Section 6.3. In addition, patients will be closely monitored for the development of any 
signs or symptoms of infections or autoimmune conditions. 
At the start of each cycle, study drug(s) will only be administered after clinical laboratory 
results have been reviewed. Administration of study drug(s) will be performed in a setting 
where emergency medical equipment and staff who are trained to respond to medical 
emergencies are available (see Section 5.2). 
Serum samples will be drawn for determination of ADA to tislelizumab and DKN-01. 
Investigators are instructed to report all AEs (including pregnancy-related AEs). 
7.2.3. 
Safety Review Team 
A safety review team (SRT) will be formed to monitor the safety of patients throughout the 
study on an ongoing basis and to determine whether to continue dosing and enrollment or to 
suggest modifications to the study design to ensure the welfare of patients.  
The SRT will meet after the first 5 patients in Part A as well as after the first 5 patients in Part 
B1 and the first 5 patients in Part B2 have completed the first cycle of study treatment, 
regularly, and on an ad hoc basis to discuss any emergent study-related safety issues. For Part 
C, a review by the SRT will occur after the first 5 patients on each chemotherapy regimen 
(CAPOX and mFOLFOX6) have completed Cycle 1 from both the experimental group (i.e., 
DKN-01 in combination of tislelizumab and chemotherapy regimen) and the control group (i.e., 
tislelizumab and chemotherapy regimen). Enrollment will continue during the safety data 
review without pause. 
7.3. 
Adverse Events 
7.3.1. 
Definitions and Reporting 
An AE is defined as any unfavorable and unintended sign (including an abnormal laboratory 
finding), symptom, or disease (new or exacerbated) temporally associated with the use of a 
study drug, whether considered related to study drug or not. 
Examples of AEs include: 
• Worsening of a chronic or intermittent preexisting condition, including an increase 
in severity, frequency, duration, and/or has an association with a significantly worse 
outcome 
• Detection or diagnosis of a new condition after study drug administration, even 
though the condition may have been present before the start of the study 
• Signs, symptoms, or the clinical sequelae of a suspected interaction 

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• Signs, symptoms, or the clinical sequelae of a suspected overdose of either study 
drug or a concurrent medication (overdose per se should not be reported as an AE or 
SAE). 
When an AE or SAE occurs, it is the responsibility of the Investigator to review all 
documentation (e.g., hospital progress notes, laboratory results, and diagnostics reports) relative 
to the AE or SAE. The Investigator will then record all relevant information regarding an AE or 
SAE in the eCRF. However, there may be instances when copies of medical records for certain 
cases are requested by the Sponsor. In this instance, all patient identifiers will be blinded on the 
copies of the medical records prior to submission to the Sponsor. 
7.3.2. 
Assessment of Severity 
The Investigator will assess the severity of each AE and SAE reported during the study. AEs 
and SAEs should be assessed and graded based upon the NCI-CTCAE v5.0. 
Toxicities that are not specified in the NCI-CTCAE will be defined 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 (ADL) 
• Grade 3: Severe or medically significant but not immediately life-threatening; 
hospitalization or prolongation of hospitalization indicated; disabling; limiting 
selfcare ADL 
• Grade 4: Life-threatening consequences; urgent intervention indicated 
• Grade 5: Death related to AE. 
Note: The terms “severe” and “serious” are not synonymous. Severity is a measure of intensity 
(e.g., grade of a specific AE, mild [Grade 1], moderate [Grade 2], severe [Grade 3], or 
life-threatening [Grade 4]), whereas seriousness is classified by the criteria based on the 
regulatory definitions. Seriousness serves as the guide for defining regulatory reporting 
obligations from the Sponsor to applicable regulatory authorities as described in Section 7.6.2. 
7.3.3. 
Assessment of Causality 
The Investigator is obligated to assess the relationship between the study drug and the 
occurrence of each AE or SAE, using best clinical judgment. Alternative causes, such as natural 
history of the underlying diseases, concomitant therapy, other risk factors, and the temporal 
relationship of the AE or SAE to the study drug should be considered and investigated. The 
Investigator should consult the DKN-01 Investigator’s Brochure or Tislelizumab Investigator’s 
Brochure in the determination of his/her assessment. 
There may be situations when an SAE has occurred, and the Investigator has only limited 
information to include in the initial report to the Sponsor. However, it is very important that the 
Investigator always assesses causality for every SAE prior to transmission of the SAE report to 
the Sponsor, because the causality assessment is one of the criteria used when determining 

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regulatory reporting requirements. The Investigator may subsequently change his/her opinion of 
causality considering follow-up information and may amend the SAE report accordingly. 
The causality of each AE should be assessed and classified by the Investigator as “related” or 
“not related” based on all information available at the time of reporting. An AE is considered 
related if there is “a reasonable possibility” that the AE may have been caused by the study drug 
(i.e., there are facts, evidence, or arguments to suggest possible causation). A number of factors 
should be considered in making this assessment, including: 
• Temporal relationship of the AE to the administration of study treatment/study 
procedure 
• Whether an alternative etiology has been identified 
• Mechanism of action of the study drug 
• Biological plausibility 
• An AE should be considered “related” to study drug if any of the following criteria 
are met, otherwise the event should be assessed as “not related”: 
• There is clear evidence to suggest a causal relationship, and other possible 
contributing factors can be ruled out 
• There is evidence to suggest a causal relationship, and the influence of other 
factors is unlikely 
• There is some evidence to suggest a causal relationship (e.g., the AE occurred 
within a reasonable time after administration of the study drug). However, the 
influence of other factors may have contributed to the AE (e.g., the patient’s 
clinical condition or other concomitant AEs). 
7.3.4. 
Follow-up of Adverse Events 
After the initial AE or SAE report, the Investigator is required to proactively follow each patient 
and provide further information to the Sponsor on the patient’s condition. 
All AEs and SAEs documented at a previous visit/contact and designated as ongoing will be 
reviewed at subsequent visits/contacts.  
All AEs and SAEs will be followed until resolution, the condition stabilizes or is considered 
chronic, the AE or SAE is otherwise explained, the patient is lost to follow-up, or the patient 
withdraws consent. The Investigator will ensure that follow-up includes any supplemental 
investigations as may be indicated to elucidate the nature and/or causality of the AE or SAE. 
This may include additional laboratory tests or investigations, histopathological examinations, 
radiographic imaging, or consultation with other health care professionals. 
The Sponsor may request that the Investigator perform or arrange for the conduct of 
supplemental measurements and/or evaluations to elucidate as fully as possible the nature 
and/or causality of the AE or SAE. The Investigator is obligated to assist. If a patient dies 
during participation in the study or during a recognized follow-up period, the Sponsor will be 
provided with a copy of any postmortem findings, including histopathology. 

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New or updated information should be reported to the Sponsor according to the SAE 
instructions provided by the Sponsor within the time frames outlined in Section 7.6.2. The 
Sponsor will consider the impact of new or updated information on the benefit-risk balance. 
7.3.5. 
Laboratory Test Abnormalities 
Abnormal laboratory findings (e.g., clinical chemistry, complete blood count, coagulation, or 
urinalysis) or other abnormal assessments (e.g., ECGs, X-rays, or vital signs) that are judged by 
the Investigator as clinically significant will be recorded as AEs or SAEs. This includes 
clinically significant abnormal laboratory findings or other abnormal assessments that are 
present at baseline and significantly worsen during the study. The definition of clinically 
significant is left to the judgment of the Investigator. In general, these are the laboratory test 
abnormalities or other abnormal assessments that: 
• Are associated with clinical signs or symptoms, or 
• Require active medical intervention, or 
• Lead to dose interruption or discontinuation, or 
• Require close observation, more frequent follow-up assessments, or further 
diagnostic investigation. 
If a clinically significant laboratory abnormality is a sign of a disease or syndrome (e.g., 
alkaline phosphatase and bilirubin 5 × ULN associated with cholestasis), only the diagnosis 
(i.e., cholestasis) should be recorded on the Adverse Event eCRF. 
If the laboratory abnormality can be characterized by a precise clinical term per standard 
definitions, the clinical term should be recorded as the AE. For example, an elevated serum 
potassium level of 7.0 mEq/L should be recorded as “hyperkalemia.” 
7.4. 
Definition of a Serious Adverse Event 
An SAE is any untoward medical occurrence that, at any dose: 
• Results in death 
• Is life-threatening 
Note: The term “life-threatening” in the definition of “serious” refers to an AE in 
which the patient was at risk of death at the time of the AE. It does not refer to an 
AE that hypothetically might have caused death if it were more severe. 
• Requires hospitalization or prolongation of existing hospitalization 
Note: In general, hospitalization signifies that the patient was admitted (usually 
involving at least an overnight stay) to the hospital or emergency ward for 
observation and/or treatment that would not have been appropriate in the physician’s 
office or outpatient setting. 
• Results in disability/incapacity 
Note: 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, 

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vomiting, diarrhea, influenza, and accidental trauma (e.g., sprained ankle), which 
may interfere with or prevent everyday life functions, but do not constitute a 
substantial disruption. 
• Is a congenital anomaly/birth defect 
• Is considered a significant medical AE by the Investigator based on medical 
judgement (e.g., may jeopardize the patient or may require medical/surgical 
intervention to prevent one of the outcomes listed above). 
The following are NOT considered to be SAEs: 
• Hospitalization for elective treatment of a preexisting condition that did not worsen 
from baseline 
• Hospitalization for social/convenience considerations 
• Scheduled therapy for the target disease of the study, including admissions for 
transfusion support or convenience. 
7.5. 
Suspected Unexpected Serious Adverse Reaction 
A suspected unexpected serious adverse reaction is a serious adverse reaction that is both 
unexpected (i.e., not present in the product’s Reference Safety Information and meets the 
definition of a serious adverse drug reaction), the specificity or severity of which is not 
consistent with those noted in the DKN-01 Investigator’s Brochure or Tislelizumab 
Investigator’s Brochure. 
7.6. 
Timing, Frequency, and Method of Capturing Adverse Events and 
Serious Adverse Events 
7.6.1. 
Adverse Event Recording Period 
A safety event that occurs during the Pre-screening (Part B Only) period (i.e., after the patient 
has signed the informed consent form for Pre-screening but prior to consent for the main study), 
will be reported as an SAE only if the event is related to a protocol -mandated procedure. In all 
study parts, after the patient signs informed consent form for the main study, all safety events 
that meet the serious criteria will be reported as SAEs. AE collection will begin after the 
administration of study drugs(s).  
Note: An SAE narrative will not be required for SAEs that occur prior to study drug 
administration unless the event was related to a protocol mandated procedure.  
After initiation of study drug, all AEs and SAEs, regardless of relationship to study drug, will 
be reported until 30 days after last dose of study drug(s) (including comparator drug/other IMP) 
or initiation of new anticancer therapy, whichever occurs first. Reporting will also discontinue if 
the patient withdraws consent. Immune-related AEs (serious or non-serious) should be reported 
until 90 days after the last dose of DKN-01 and tislelizumab, regardless of whether or not the 
patient starts a new anticancer therapy. All SAEs considered related to the study drug(s) that are 
brought to the attention of the Investigator should be reported regardless of time since the last 
dose of treatment. 

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AEs and SAEs should be recorded according to the details in Table 16. For the follow-up period 
for AEs, see Section 7.3.4.  
Table 16: 
Guidance for Duration of Recording New or Worsening Adverse Events in 
All Treatment Arms 
Event type 
Record new or worsening events that occur during this period 
Begin 
End  
SAEsa 
Signing of informed 
consentb 
Up to 30 days after last dose, initiation of 
new anticancer therapy, death, withdrawal 
of consent, or loss to follow-up, whichever 
occurs first 
Nonserious AEs and SAEs 
due to PD 
Do not record (see Section 7.6.4) 
All nonserious AEs, except 
those due to PD 
First dose of study drug 
Up to 30 days after last dose, initiation of 
new anticancer therapy, death, withdrawal 
of consent, or loss to follow-up, whichever 
occurs first 
Immune-related AEs (serious 
or nonserious) 
 
Up to 90 days after last dose (regardless of 
initiation of new anticancer therapy), 
death, withdrawal of consent, or loss to 
follow-up, whichever occurs first 
Abbreviations: AE = adverse event; PD = progressive disease; SAE = serious adverse event. 
a All SAEs considered related to the study drug(s) that are brought to the attention of the Investigator should be 
reported regardless of time since the last dose of treatment. 
b See Section 7.6.1 for SAEs occurring after pre-consent prior to main consent (Part B only) 
7.6.2. 
Reporting Serious Adverse Events 
7.6.2.1. 
Prompt Reporting of Serious Adverse Events 
As soon as the Investigator determines that an AE meets the protocol definition of an SAE, the 
event must be reported promptly (within 24 hours) to the Sponsor or designee as described in 
Table 17. 
Table 17: 
Timeframes and Documentation Methods for Reporting Serious Adverse 
Events to the Sponsor or Designee 
 
Timeframe for 
Sending Initial 
Report 
Documentation 
Method 
Timeframe 
for Sending 
Follow-up 
Report 
Documentation 
Method 
Reporting 
Method 
All SAEs 
with 
exception of 
PD  
Within 24 hours 
of first 
knowledge of 
the SAE 
SAE Report 
As 
expeditiously 
as possible 
SAE Report 
Email or fax 
SAE Report 
form 
Abbreviations: PD = progressive disease; SAE = serious adverse event. 

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7.6.2.2. 
Completion and Transmission of the Serious Adverse Event Report 
Once an Investigator becomes aware that an SAE has occurred in a patient, he/she is to report 
the information to the Sponsor within 24 hours as outlined above in Section 7.6.2.1. The SAE 
Report will always be completed as thoroughly as possible with all available details of the event 
and forwarded to the Sponsor or designee within the designated time frames. 
If the Investigator does not have all information regarding an SAE, he/she is not to wait to 
receive additional information before notifying the Sponsor or designee of the SAE and 
completing the form. The form will be updated when additional information is received. 
The Investigator must always provide an assessment of causality for each SAE prior to 
transmission of the SAE report to the Sponsor, as described in Section 7.3.3. 
The Sponsor will provide contact information for SAE reporting. 
7.6.2.3. 
Regulatory Reporting Requirements for Serious Adverse Events 
The Investigator will report all SAEs to the Sponsor in accordance with the procedures detailed 
in Section 7.6.2.1. The Sponsor has a legal responsibility to notify, as appropriate, both the local 
regulatory authority and other regulatory agencies about the safety of a product under clinical 
investigation. 
The Investigator, or responsible person according to local requirements, will comply with the 
applicable local regulatory requirements related to the reporting of SAEs to regulatory 
authorities and the IRB/IEC. 
All suspected unexpected serious adverse reactions (as defined in Section 7.5), will be 
submitted to all applicable regulatory authorities and Investigators for tislelizumab studies. 
Where applicable, the Sponsor will report all unexpected events which affect the benefit-risk 
balance of the clinical trial (which are not suspected unexpected serious adverse reactions) no 
later than 15 days of becoming aware. 
When a study center receives an initial or follow-up safety report or other safety information 
(e.g., revised Investigator’s Brochure[s]) from the Sponsor, the Investigator or designated 
responsible person is required to promptly notify his/her IRB or IEC per institutional SOPs. The 
Investigator should place copies of Safety Reports from the Sponsor in the Investigator Site 
File. 
Where applicable, serious adverse reactions occurring after the end of the study should be 
reported without undue delay. 
7.6.3. 
Eliciting Adverse Events 
The Investigator or designee will ask patients about AEs by asking the following standard 
questions: 
• How are you feeling? 
• Have you had any medical problems since your last visit? 
• Have you taken any new medicines since your last visit? 

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7.6.4. 
Disease Progression 
Disease progression, which is expected in this study population and measured as an efficacy 
endpoint, should not be recorded as an AE term. Similarly, nonserious AEs that are clearly 
consistent with the pattern of progression of the underlying disease and are considered 
unequivocally due to disease progression should not be recorded. However, if there is any 
uncertainty as to whether a nonserious AE is due to disease progression, it should be recorded 
as an AE. Serious adverse events due to disease progression, including death, should not be 
reported unless the Investigator deems them to be possibly related to the study drug (see 
Section 7.6.2). Disease progression and clinical progression are captured in the clinical database 
(i.e., tumor assessment, EOT, and EOS eCRFs). Death related to clinical/RECIST disease 
progression are captured on the Death and EOS eCRFs.  
7.6.5. 
Deaths 
Death is an outcome and not usually considered an event. If the only information available is 
death and the cause of death is unknown, then the death is reported as an AE, e.g., “death,” 
“death of unknown cause,” or “death unexplained.” 
7.6.6. 
Pregnancies 
If a female patient or the partner of a male patient becomes pregnant while receiving 
investigational therapy or within 180 days after the last dose of DKN-01 or tislelizumab a 
pregnancy report form is required to be completed and expeditiously submitted to the Sponsor 
to facilitate outcome follow-up. Information on the status of the mother and child will be 
forwarded to the Sponsor. Generally, follow-up will be no longer than 6 to 8 weeks following 
the estimated delivery date. Any premature termination of the pregnancy will be reported. 
While pregnancy itself is not considered to be an AE, any pregnancy complication or elective 
termination of a pregnancy for medical reasons will be recorded as an AE or SAE. 
An abortion, whether accidental, therapeutic, or spontaneous, should be always reported as an 
SAE. Similarly, any congenital anomaly/birth defect in a child born to a patient exposed to the 
study drug should be recorded and reported as an SAE. 
7.6.7. 
Expedited Reporting to Health Authorities, Investigators, Institutional Review 
Boards, and Independent Ethics Committees 
The Sponsor will promptly assess all SAEs against cumulative study drug experience to identify 
and expeditiously communicate new safety findings to regulatory authorities, Investigators, 
IRBs, and IECs based on applicable legislation. 
To determine the reporting requirements for individual SAEs, the Sponsor will assess the 
expectedness of the SAEs using the following reference safety information documents: 
• Tislelizumab Investigator’s Brochure 
• DKN-01 Investigator’s Brochure 

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7.6.8. 
Assessing and Recording Immune-Related Adverse Events 
Since treatment with anti-PD-1 therapy can cause autoimmune disorders, AEs considered by the 
Investigator to be immune-related (see Appendix 8) should be classified as irAEs and identified 
as such in the eCRF AE page. Not all tislelizumab studies include a section on the eCRF AE 
page where irAEs are clearly identified. Therefore, all studies will rely on the company list of 
potential irAE preferred terms to identify all cases in each study to be further assessed as 
immune-related AEs by the Sponsor, in addition to those irAEs reported by the Investigator via 
the AE CRF page. 
Investigators should consult the guidance on diagnostic evaluation and management of irAEs, 
which are commonly seen with immune checkpoint inhibitors, in Appendix 8. 
All conditions similar to those listed should be evaluated to determine whether they are irAEs, 
based on a similar diagnostic process to those reactions that are presented in more detail in 
Appendix 8. 
7.6.9. 
Recording Infusion-Related Reactions 
The symptoms of infusion-related reactions may include, but are not limited to, fever, 
chills/rigor, nausea, pruritus, angioedema, hypotension, headache, bronchospasm, urticaria, 
rash, vomiting, myalgia, dizziness, or hypertension. Severe reactions (see CTCAE v5.0, page 67 
under the Injury, Poisoning and Procedural Complications SOC, Appendix 12, and 
Appendix 13) may include acute respiratory distress syndrome, syncope, myocardial infarction, 
ventricular fibrillation, or cardiogenic shock.  
7.6.10. 
Medication Errors 
A medication error is an unintended failure in the drug treatment process that leads to, or has the 
potential to lead to, harm to the patient. 
Any medication errors with DKN-01, tislelizumab, or capecitabine/oxaliplatin/fluorouracil 
chemotherapy should be noted in the patient’s chart and on the appropriate eCRF. AEs 
associated with an overdose or incorrect administration of study drug will be recorded on the 
AE eCRF. Any SAEs associated with an overdose or incorrect administration must be reported 
within 24 hours of awareness via the SAE reporting process described in Section 7.6.2. 
Supportive care measures should be administered as appropriate. 
7.6.11. 
Overdose 
DKN-01, tislelizumab, oxaliplatin, leucovorin calcium, and fluorouracil to be used in this 
protocol will be administered by the study team. Patients will not self-administer these study 
medications.  
Patients will self-administer capecitabine twice daily on Days 1 through 15 of each cycle for a 
total of 28 doses. 
7.6.11.1. DKN-01 
There have been no instances of medication error or overdose of DKN-01 during clinical 
studies. 

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Any overdose or incorrect administration of DKN-01 should be noted in the patient’s chart and 
on the appropriate eCRF. AEs associated with an incorrect administration of DKN-01 will be 
recorded on the AE eCRF. Any SAEs associated with an overdose or incorrect administration 
must be reported within 24 hours of awareness via the SAE reporting process described in 
Section 7.6.2. Supportive care measures should be administered as appropriate. 
7.6.11.2. Tislelizumab 
Any overdose of tislelizumab (defined as ≥600 mg in a 24-hour period) should be noted in the 
patient’s chart and on the appropriate eCRF. AEs associated with an overdose of study drug will 
be recorded on the AE eCRF. Any SAEs associated with an overdose must be reported within 
24 hours of awareness via the SAE reporting process described in Section 7.6.2. Supportive care 
measures should be administered as appropriate. 
7.6.11.3. Oxaliplatin  
There is no known antidote for oxaliplatin overdose (Eloxatin 2015). In addition to 
thrombocytopenia, the anticipated complications of an oxaliplatin overdose include 
hypersensitivity reaction, myelosuppression, nausea, vomiting, diarrhea and neurotoxicity. 
Several cases of overdoses have been reported with oxaliplatin. Adverse reactions observed 
were Grade 4 thrombocytopenia (<25,000/mm3) without any bleeding, anemia, sensory 
neuropathy such as paresthesia, dysesthesia, laryngospasm and facial muscle spasms, 
gastrointestinal disorders such as nausea, vomiting, stomatitis, flatulence, abdomen enlarged 
and Grade 4 intestinal obstruction, Grade 4 dehydration, dyspnea, wheezing, chest pain, 
respiratory failure, severe bradycardia and death. Patients suspected of receiving an overdose 
should be monitored, and supportive treatment should be administered. The maximum dose of 
oxaliplatin that has been administered in a single infusion is 825 mg. 
7.6.11.4. Capecitabine 
The manifestations of acute overdose would include nausea, vomiting, diarrhea, gastrointestinal 
irritation and bleeding, and bone marrow depression (Xeloda 2015). Medical management of 
overdose should include customary supportive medical interventions aimed at correcting the 
presenting clinical manifestations. Although no clinical experience using dialysis as a treatment 
for capecitabine overdose has been reported, dialysis may be of benefit in reducing circulating 
concentrations of 5’-DFUR, a low–molecular-weight metabolite of the parent compound. 
Single doses of capecitabine were not lethal to mice, rats, and monkeys at doses up to 
2000 mg/kg (2.4, 4.8, and 9.6 times the recommended human daily dose on an mg/m2 basis). 
7.6.11.5. Leucovorin calcium  
Excessive amounts of leucovorin calcium may nullify the chemotherapeutic effect of folic acid 
antagonists (Leucovorin calcium 2012). 
7.6.11.6. Fluorouracil 
Administer uridine triacetate within 96 hours following the end of fluorouracil infusion for 
management of fluorouracil overdose. (Fluorouracil 2016). 

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8. 
STATISTICAL CONSIDERATIONS 
8.1. 
Part A and Part B  
8.1.1. 
Sample Size Determination 
The sample size for Part A and B of this Phase 2 study is not based on formal statistical 
calculations as this is a pilot study designed primarily to seek information on the safety, 
efficacy, and pharmacokinetics/pharmacodynamics of DKN-01 in combination with 
tislelizumab ± CAPOX. Data collected from previous clinical studies indicates that DKN-01 is 
well tolerated. It was therefore determined that 20 patients would be sufficient to assess the 
safety and tolerability of DKN-01 in combination with tislelizumab ± CAPOX in a pilot study. 
Approximately 24 patients (first-line treatment) will be enrolled in Part A to ensure 20 
evaluable patients. Approximately 48 patients (DKK1-high G/GEJ adenocarcinoma, second-line 
treatment) will be enrolled in Part B to ensure 40 evaluable patients. With a sample size of 20 
evaluable patients in Part A, observed ORR rates of 69%, 77%, or 80% would be statistically 
greater than the 50% expected success rate at a 0.05 one-sided significance level with at least 
50%, 80%, or 90% power, respectively(Klempner, Bendell et al. 2020). With a sample size of 
40 evaluable patients in Part B, observed ORR rates of 42%, 49%, or 53% would be statistically 
greater than the ≥30% expected success rate at a 0.05 one-sided significance level with at least 
50%, 80%, or 90% power, respectively.  
It is estimated that approximately 180 patients will be screened to achieve the target of 
24 patients enrolled in Part A and 48 patients in Part B. 
8.2. 
Part C 
8.2.1. 
Statistical Hypothesis 
The primary efficacy endpoint is PFS, and the study is designed to test the superiority of DKN-
01 plus tislelizumab and chemotherapy (CAPOX or mFOLFOX6), the experimental treatment, 
over tislelizumab and chemotherapy (CAPOX or mFOLFOX6), the control treatment, for 
DKK1-high and in all patients. The primary analysis will test the following hypotheses: 
• Null Hypothesis: The hazard ratio for PFS between experimental and control treatment 
is equal to one. 
• Alternative Hypothesis: The hazard ratio for PFS between experimental and control 
treatment is less than one.  
8.2.2. 
Sample Size Determination 
The sample size for Part C of this Phase 2 study is based on formal statistical calculations as this 
part of the study is designed primarily to seek information on the efficacy of DKN-01 in 
combination with tislelizumab and chemotherapy regimen (CAPOX or mFOLFOX6) as 
compared to the combination of tislelizumab and chemotherapy regimen (CAPOX or 
mFOLFOX6) alone in DKK1-high patients and in patients regardless of their DKK1 status (all-
comers). It is determined that a total of approximately160 patients (80 patients in each treatment 

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group) would be sufficient to assess the efficacy of DKN-01 in combination with tislelizumab 
and chemotherapy for DKK1-high patients and in patients regardless of their DKK1 status.  
With a power of 83% and a one-sided Type I error of 10%, a total of 137 PFS events of all-
comers are required to detect a treatment effect hazard ratio of 0.681 (median PFS for all-
comers is 7.7 months in the control arm and 11.3 months in the experimental arm). With a 
power of 80% and a one-sided Type I error of 10%, a total of 49 PFS events of DKK1-high 
patients are required to detect a treatment effect hazard ratio of 0.546 (median PFS for DKK1-
high patients is 6.5 months in the control arm and 11.9 months in the experimental arm) in 
DKK1-high patients. 
The sample size and power calculations are based on the following assumptions: Assuming a 
recruitment period of 12 months, a 10% probability of dropping out during the course of the 
study, a minimum follow-up of 24 months, and approximately 50% patients will be DKK1-
high. If the proportion of DKK1 high patients is not 50%, the power of PFS in DKK1-high 
patients will vary and may require further evaluation. 
Both sample size calculations have been performed using the STT2 module (Two Sample Log-
Rank Test of Exponential Survival with Exponential Dropout) of nQuery Version 9.2.1.0 from 
Statistical Solutions Ltd.  
 

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8.3. 
Populations for Analyses 
For purposes of analysis, the following populations are defined: 

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Description 
Enrolled  
All patients who signed the main study informed consent form 
(ICF). 
Safety Population 
 
For Part A and B: All patients who signed the ICF and received 
at least 1 dose of DKN-01. This is the primary population for the 
Safety Analysis. 
For Part C: The safety population is defined as all patients who 
are randomized and receive at least one dose of study treatment. 
Efficacy  
Intent-to-Treat (ITT) Population 
For Part A and B: The intent-to-treat population (full analysis set) 
is defined to be all patients who enrolled and received at least one 
dose of DKN-01. 
For Part C: The Intent-to-treat population is defined to be all 
patients randomized to treatment. Patients will be included in the 
treatment group assigned at randomization regardless of the 
actual treatment received. 
Modified Intent-to-Treat (mITT) Population  For Part A and B: All patients who received more than one dose 
of DKN-01. This is the primary population for the efficacy 
analyses including PFS and OS.  
For Part C: All randomized patients who receive at least one 
cycle of study treatment.  
Response Evaluable Population 
Part A: All patients who received any amount of DKN-01 + 
tislelizumab + oxaliplatin + capecitabine and have measurable 
baseline and at least 1 evaluable post-baseline RECIST tumor 
response assessment. 
Part B1 and B2: All patients who received any amount of DKN-
01 + tislelizumab and have a measurable baseline and at least 1 
evaluable post baseline RECIST tumor response assessment. 
Part C: All patients who received any amount of tislelizumab + 
chemotherapy regimen (CAPOX or mFOLFOX6) ± DKN-01 and 
have measurable baseline and at least 1 evaluable post-baseline 
RECIST tumor response assessment. 
Per-Protocol (PP) Population 
Part A and B: All enrolled patients without important protocol 
deviations that necessitates exclusion from this population or 
compliance issues, as applicable.  
Part C: All patients who are randomized and received the study 
treatment (Tislelizumab + chemotherapy (CAPOX or 
mFOLFOX6) ± DKN-01) as planned and have no important 
protocol deviations. The PP population will be used for 
sensitivity analyses of the primary and secondary objectives. 
Pharmacokinetics Population DKN-01 
All enrolled patients with available serum-time concentration 
data from patients dosed with DKN-01.  
Pharmacokinetics Population tislelizumab 
All enrolled patients with available serum-time concentration 
data from patients dosed with tislelizumab 

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Biomarker population 
There is one biomarker population for each of the following 
biomarkers: 
- DKK1 tumor expression in messenger RNA (mRNA) by 
chromogenic in situ hybridization (CISH). 
- Programmed cell death protein ligand-1 (PD-L1) expression by 
IHC 
Abbreviations: DKK1 = Dickkopf-1; ICF = informed consent form; PD-L1 = programmed cell death protein ligand 1. 
8.4. 
Statistical Analyses 
This section is a summary of the planned statistical analyses of the primary and secondary 
endpoints. 
Data analyses in general will be primarily descriptive and presented by study part and overall; 
full details will be provided in the Statistical Analysis Plan. For continuous safety and efficacy 
variables, descriptive statistics (n-number of patients with data, mean, standard deviation, 
median, minimum, and maximum) will be presented. For categorical variables, frequency 
distributions (counts and associated percentages) will be presented. 
The statistical analysis plan will be developed and finalized before final database lock and will 
describe the patient populations to be included in the analyses, and the procedures for 
accounting for missing, unused, and spurious data. 
8.4.1. 
Efficacy Analyses 
8.4.1.1. 
Part A and B 
For Study Parts A and B, the modified intent-to-treat population is the primary efficacy 
population. Additional summaries may be created for the response evaluable population, the 
per-protocol population, and the safety population.  Efficacy endpoints will also be assessed for 
subgroups of interest. Any statistical results will be interpreted in the perspective of the 
exploratory nature of the study.  
The best overall response (BOR) will be determined in accordance with RECIST v1.1. The 
following response rates will be presented by study part: ORR, DCB, and DCR. The time to 
event endpoints (DOR, PFS, and OS) will be assessed by the Kaplan-Meier method. Estimated 
median, 25th and 75th percentiles, and standard errors from Kaplan-Meier summaries will be 
presented for the time-to-event data. 
8.4.1.2. 
Part C  
Analysis of the primary efficacy endpoint 
The primary endpoint is PFS, which is measured from the date of randomization to the date of 
documented disease progression, based on Investigator assessed radiologic review using 
RECIST v1.1, or death due to any cause, whichever occurs first. If the patient has not died, but 
there is no radiographic post-baseline tumor assessment, PFS will be censored at the date of 
randomization. If there are radiographic post-baseline tumor assessments, PFS will be censored 
at the most recent tumor assessment before the data cutoff or study withdrawal, whichever 
occurs first. 

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The primary analysis will be the comparison of PFS for DKK1-high and in all patients between 
the two treatment arms in the ITT population, using the one-sided stratified log-rank test, with 
stratification factors as used in the randomization. Data will be summarized in Kaplan-Meier 
curves together with medians and 95% confidence intervals for those medians. The Cox 
Proportional Hazards model, stratified for the randomization factors, will be used to obtain a 
hazard ratio together with its 95% confidence interval.  
No multiplicity adjustment is planned for the treatment comparisons of the primary endpoint as 
this is a Phase 2 study for exploratory and for signal finding purpose. All other efficacy analyses 
will be considered exploratory. 
Analysis of secondary endpoints 
ORR is defined as the proportion of patients who achieve objective tumor response (CR or PR) 
per RECIST 1.1, assessed by the Investigator. The comparison of ORR between the two 
treatment arms will be based on the Cochran-Mantel-Haenzel test, with stratification factors as 
for the analysis of PFS. Results will be reported in terms of an odds ratio and the associated 
95% confidence interval using the Clopper-Pearson method (Clopper 1934). Results will also be 
summarized by treatment arms and appropriate subgroups.  
For DOR, PFS, and OS, the time to event curves between the two treatment arms will be 
compared with a log-rank test along with the corresponding hazard ratio.  
In general, confidence intervals (95%, unless otherwise stated) will be presented for select 
efficacy variables. Standard figures for summarizing the response to treatment overall and 
within subgroups, will be provided.  
Overall Survival (OS) is defined as the time from the date of randomization to death due to any 
cause. For a patient who is not known to have died by the end of study follow-up, observation 
of OS is censored on the date the patient was last known to be alive (i.e., date of last contact). 
Patients lacking data beyond the day of randomization will have their survival time censored on 
the date of randomization (i.e., OS duration of 1 day). 
Other Aspects of the Efficacy Analysis 
All primary and secondary efficacy analyses may be repeated in the PP population. 
The concordance between Investigator assessment and central imaging assessment will be 
evaluated.  
Subgroup Analyses  
Hazard ratios and 95% confidence intervals will be calculated for PFS within subgroups using 
the unadjusted Cox proportional hazards model in order to evaluate the consistency of treatment 
effect. These subgroups will include those defined by the stratification factors. Other subgroups 
may also be considered, with a full list being identified in the SAP. 
8.4.2. 
Safety Analyses 
All safety analyses will be performed on the Safety Population. Analyses will be described in 
detail in the statistical analysis plan and will include summaries of adverse events, laboratory 
events, vital signs, ECGs, physical examination, ECOG findings, drug exposure and dose 
modifications, including dose interruptions. 

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AEs that occur after signing informed consent and prior to administration of study treatment 
will not be considered as treatment emergent but will be collected and listed. Adverse event 
summaries will be based on treatment-emergent adverse events (TEAEs), defined as any AE 
that occurs during or after administration of the first dose of treatment through 30 days after the 
last dose, or any event that is present at baseline but worsens in intensity. 
8.4.3. 
Other Analyses  
The DKN-01 concentration data are sparse in nature, and therefore no formal PK analyses are 
planned for this study. Concentration data for both DKN-01 and DKK1 will be collected and 
summarized by nominal collection time. Mean concentration-time graphs by dose group may be 
prepared. In addition, the concentration data will be characterized by dose level and drug 
administration. At each nominal collection time, values for the mean, standard deviation, 
median, minimum and maximum will be reported as applicable. 
Univariate and multivariate models will be used to evaluate biomarker endpoints in relation to 
efficacy outcomes. Multivariate analysis will be conducted to determine if DKK1 expression is 
associated with clinical benefit independently of known predictors to checkpoint inhibitor 
therapies (e.g., PD-L1, microsatellite stability status and TMB).  

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9. 
SOURCE DOCUMENTS AND ACCESS TO SOURCE 
DATA/DOCUMENTS 
The Investigator must maintain adequate and accurate records to ensure that the conduct of the 
study may be fully documented. Such records include, but are not limited to, the protocol, 
protocol modifications (hereafter referred to as amendments), ICFs, and documentation of 
IRB/IEC and governmental approvals. In addition, at the end of the study, the Investigator will 
receive patient data, which will include an audit trail containing a complete record of all 
changes to such data. 
9.1. 
Access to Information for Monitoring 
In accordance with International Council for Harmonisation (ICH) Good Clinical Practice 
(GCP) guidelines, the study monitor must have direct access to the Investigator’s source 
documentation in order to verify the data recorded in the eCRFs for consistency. 
The monitor is responsible for routine review of the eCRFs at regular intervals throughout the 
study to verify adherence to the protocol and the completeness, consistency, and accuracy of the 
data being entered on them. The monitor should have access to any patient records needed to 
verify the entries on the eCRFs. The Investigator agrees to cooperate with the monitor to ensure 
that any problems detected during these monitoring visits are resolved. 
Off-site monitoring may be performed. Any off-site monitoring will be performed in 
accordance with local regulations, where applicable. 
9.2. 
Access to Information for Auditing or Inspections 
Representatives of regulatory authorities or of BeiGene or Leap may conduct inspections or 
audits any time during or after completion of this clinical study. If the Investigator is notified of 
an inspection by a regulatory authority, the Investigator agrees to notify the Sponsor or its 
designee immediately. The Investigator agrees to provide to representatives of a regulatory 
agency or BeiGene access to records, facilities, and personnel for the effective conduct of any 
inspection or audit. 

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10. 
QUALITY ASSURANCE AND QUALITY CONTROL 
10.1. 
Regulatory Authority Approval 
The Sponsor will obtain approval to conduct the study from the appropriate regulatory agency 
in accordance with any applicable country specific regulatory requirements or file the protocol 
to the appropriate regulatory agency before the study is initiated at a study center in that 
country. 
10.2. 
Quality Assurance 
To ensure compliance with GCP and all applicable regulatory requirements, the Sponsor may 
conduct a quality assurance audit. Regulatory agencies may also conduct a regulatory inspection 
of this study. Such audits/inspections can occur at any time during or after completion of the 
study. If an audit or inspection occurs, the Investigator and institution agree to allow the 
auditor/inspector direct access to all relevant documents and to allocate his/her time and the 
time of his/her personnel to the auditor/inspector to discuss findings and any relevant issues. 
10.3. 
Study Site Inspections 
This study will be organized, performed, and reported in compliance with the protocol, standard 
operating procedures, working practice documents, and applicable regulations and guidelines. 
Site audits may be performed periodically by the Sponsor’s or the contract research 
organization’s qualified compliance auditing team, which is an independent function from the 
study team responsible for conduct of the study. 
Site visits will be conducted by the Sponsor or an authorized representative to inspect study 
data, patients’ medical records, and eCRFs. The Investigator is to permit national and local 
health authorities; Sponsor study monitors, representatives, and collaborators; and IRB/IEC 
members to inspect all facilities and records relevant to this study.  
10.4. 
Drug Accountability 
The Investigator or designee (i.e., pharmacist) is responsible for ensuring adequate 
accountability of all used and unused study drug. This includes acknowledgment of receipt of 
each shipment of study product (quantity and condition), patient drug dispensation records, and 
returned or destroyed study product. Dispensation records will document quantities received 
from BeiGene’s or Leap’s designated depot or its designee and quantities dispensed to patients, 
including batch/lot number, date dispensed, patient identifier number, and the initials of the 
person dispensing the medication. 
At study initiation, the monitor will evaluate the site’s standard operating procedure for study 
drug disposal/destruction to ensure that it complies with BeiGene and Leap requirements 
specified in the Pharmacy Manual. At appropriate times during the conduct of the study or at 
the end of the study following final drug inventory reconciliation by the monitor, the study site 
will dispose of and/or destroy all unused study drug supplies, including empty containers, 
according to these procedures. If the site cannot meet BeiGene’s or Leap’s requirements 
specified in the Pharmacy Manual for disposal, arrangements will be made between the site and 
BeiGene or Leap or its representative for destruction or return of unused study drug supplies. 

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All drug supplies and associated documentation will be periodically reviewed and verified by 
the study monitor over the course of the study. 

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11. 
ETHICS/PROTECTION OF HUMAN PATIENTS 
11.1. 
Ethical Standard 
This study will be conducted by the Principal Investigator and the study center in full 
conformance with the ICH E6 guideline for Good Clinical Practice and the principles of the 
Declaration of Helsinki or the laws and regulations of the country in which the research is 
conducted, whichever affords the greater protection to the patient. The study will also comply 
with the requirements of the ICH E2A guideline (Clinical Safety Data Management: Definitions 
and Standards for Expedited Reporting). 
11.2. 
Institutional Review Board/Independent Ethics Committee 
This protocol, the ICFs, any information to be given to the patient, and relevant supporting 
information must be submitted, reviewed, and approved by the IRB/IEC before the study is 
initiated. In addition, any patient recruitment materials must be approved by the IRB/IEC. 
Copies of the IEC/IRB correspondence and approval of the amended ICF/other information and 
the approved amended ICF/other information must be forwarded to the Sponsor promptly. 
The Principal Investigator is responsible for 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. Investigators are also responsible for promptly 
informing the IRB/IEC of any protocol amendments. In addition to the requirements for 
reporting all AEs to the Sponsor, Investigators must comply with requirements for reporting 
SAEs to the local health authority and IRB/IEC. Investigators may receive written 
investigational new drug (IND) safety reports or other safety-related communications from the 
Sponsor. Investigators are responsible for ensuring that such reports are reviewed and processed 
in accordance with health authority requirements and the policies and procedures established by 
their IRB/IEC and archived in the site’s study file. 
11.3. 
Protocol Amendments 
Any protocol amendments will be prepared by the Sponsor. All protocol modifications must be 
submitted to competent authorities according to local requirements and to the IRB/IEC together 
with, if applicable, a revised model ICF in accordance with local requirements. Written 
documentation from competent authorities (according to local requirements) and from the 
IRB/IEC and required site approval must be obtained by the Sponsor before changes can be 
implemented, except for changes necessary to eliminate an immediate hazard to patients or 
changes that involve logistical or administrative aspects only (e.g., change in Medical Monitor 
or contact information). 
Information on any change in risk and/or change in scope must be provided to patients already 
actively participating in the study, and they must read, understand, and sign each revised ICF 
confirming their willingness to remain in the study. 

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11.4. 
Informed Consent  
The Sponsor’s sample ICF will be provided to each site. If applicable, it will be provided in a 
certified translation of the local language. The final IRB/IEC-approved ICFs must be provided 
to the Sponsor for health authority submission purposes according to local requirements. 
Patients must be informed that their participation is voluntary. Patients or their healthcare proxy 
will be required to sign a statement of informed consent that meets the requirements, where 
applicable, of 21 CFR 50, ICH guidelines, Health Insurance Portability and Accountability Act 
requirements, EU CTR 536/2014, local regulations, and the IRB/EC or study center. 
The ICFs must be signed and dated by the patient or the patient’s legally authorized 
representative before his or her participation in the study. The case history or clinical records for 
each patient shall document the informed consent process and that written informed consent 
was obtained prior to participation in the study. 
The ICFs will be revised whenever there are changes to study procedures or when new 
information becomes available that may affect the willingness of the patient to participate. The 
final revised IRB-/IEC-approved consent forms must be provided to the Sponsor for health 
authority submission purposes. 
Patients must be reconsented to the most current version of the ICFs (or to a significant new 
information/findings addendum in accordance with applicable laws and IRB/IEC policy) during 
their participation in the study. For any updated or revised ICFs, the case history or clinical 
records for each patient shall document the informed consent process and that written informed 
consent was obtained using the updated/revised ICFs for continued participation in the study. 
A copy of each signed ICF must be provided to the patient or the patient’s legally authorized 
representative. All signed and dated ICFs must remain in each patient’s study file or in the site 
file and must be available for verification by study monitors at any time. 
11.5. 
Patient and Data Confidentiality 
The principal Investigator and Sponsor will maintain confidentiality and privacy standards by 
following applicable data privacy laws covering the collection, storage, transmission, and 
processing of patients’ personal and medical information. 
The principal Investigator shall code the medical information obtained during the study with a 
unique patient identification number assigned to each patient enrolled in the study. This 
approach ensures that patients’ names are not included in any dataset transmitted to any Sponsor 
location. 
Patient medical information obtained during this study is confidential and may be disclosed 
only to third parties as permitted by the signed ICF (or a separate authorization for the use and 
disclosure of personal health information that has been signed by the patient), unless permitted 
or required by law. 
In the event of a breach of the confidentiality of a patient’s personal and medical information, 
the principal Investigator and Sponsor, as appropriate, shall fulfill all mediation steps and 
reporting obligations under applicable data privacy laws. 

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If a serious breach of the EU CTR 536/2014 or of the protocol occurs that is likely to affect the 
safety, rights of study patients and/or data reliability and robustness to a significant degree, this 
must be reported by the Sponsor in the EU Clinical Trials Information System within 7 days. 
The Sponsor’s (or designee’s) process will be in place to support this. Any serious breaches will 
be reported in the clinical study report. 
Medical information may be given to a patient’s personal physician or other appropriate 
medical personnel responsible for the patient’s welfare for treatment purposes. 
Data generated during this study must be available for inspection upon request by 
representatives of the US Food and Drug Administration and all other national and local health 
authorities; by Sponsor monitors, representatives, and collaborators; and by the IRBs/IECs for 
each study site, as appropriate. 
The Investigator must ensure that patients’ anonymity will be strictly maintained and that their 
identities are protected from unauthorized parties. The Investigator agrees that all information 
received from the Sponsor, including but not limited to, the Investigator’s Brochure[s], this 
protocol, eCRFs, the IND, and any other study information, remain the sole and exclusive 
property of the Sponsor during the conduct of the study and thereafter. This information is not 
to be disclosed to any third party (except employees or agents directly involved in the conduct 
of the study or as required by law) without prior written consent from the Sponsor. The 
Investigator further agrees to take all reasonable precautions to prevent the disclosure by any 
employee or agent of the study site to any third party or otherwise into the public domain. 
If a written contract for the conduct of the study is executed, and that contract includes 
confidentiality provisions inconsistent with this section, that contract’s provisions shall apply to 
the extent they are inconsistent with this section. 
11.6. 
Financial Disclosure 
Investigators are required to provide the Sponsor with sufficient accurate financial information 
in accordance with regulations to allow the Sponsor to submit complete disclosure or 
certification to the absence of certain financial interest of the Investigators, and/or disclose those 
financial interests, as required, to the appropriate health authorities. This is intended to ensure 
financial interests and arrangements of the Investigators with Leap Therapeutics and BeiGene 
that could affect reliability of data submitted to health authorities are identified and disclosed by 
the Sponsor. Investigators are responsible for providing information about their financial 
interests before participation in the study and to update this information if any relevant changes 
occur during the study and for 1 year after completion of the study (i.e., last patient, last visit). 
11.7. 
Data Handling and Record Keeping 
11.7.1. 
Data Collection and Management Responsibilities 
11.7.1.1. Data Entry in the Electronic Case Report Form 
All study-related data collected or received by the Investigator or study team shall be promptly 
entered into the eCRFs. In no event should the entry of the study data into the eCRF be later 
than what is stipulated in the site contract after the data is collected or received by the 
Investigator or study team without prior communication with and approval by the Sponsor. 

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11.7.1.2. Data Collection 
Data required by the protocol will be entered into an electronic data capture (EDC) system. 
Data collection in the eCRF should follow the instructions described in the eCRF Completion 
Guidelines. The Investigator has ultimate responsibility for the collection and reporting of all 
clinical data entered in the eCRF. The e-signature of the Investigator or designee must be 
provided in the EDC system to attest to its accuracy, authenticity, and completeness. 
Data contained in the eCRFs are the sole property of Leap Therapeutics and BeiGene and 
should not be made available in any form to third parties without written permission from Leap 
Therapeutics and BeiGene, except for authorized representatives of Leap Therapeutics and 
BeiGene or appropriate regulatory authorities. 
11.7.1.3. Data Management/Coding 
All final patient data, both eCRF and external data (e.g., laboratory data), collected according to 
the protocol will be stored by Leap Therapeutics and BeiGene at the end of the study. 
Standard procedures (including following data review guidelines, computerized validation to 
produce queries, and maintenance of an audit file that includes all database modifications) will 
be followed to support accurate data collection. Data will be reviewed for outliers, logic, data 
inconsistencies, and completeness. 
During the study, a study monitor (clinical research associate) will make site visits to review 
protocol compliance, compare eCRFs against individual patient’s medical records, and ensure 
that the study is being conducted according to pertinent regulatory requirements. 
The eCRF entries will be verified with source documentation. The review of medical records 
will be performed in a manner to ensure that patient confidentiality is maintained. Checking the 
eCRFs for completeness, clarity, and cross-checking with source documents is required to 
monitor the progress of the study. Direct access to source data is also required for inspections 
and audits and will be carried out with due consideration given to data protection and medical 
confidentiality. 
The AE verbatim descriptions (the Investigator’s description from the eCRF) will be coded 
using the Medical Dictionary for Regulatory Activities (MedDRA). AEs will be coded to 
MedDRA by lower-level term, preferred term, and primary system organ class. Concomitant 
medications will be coded using the World Health Organization Drug Dictionary. Concomitant 
diseases/medical history will be coded using MedDRA. 
11.8. 
Data Integrity and In-house Blinding 
Functions/persons with access to the EDC system shall be prohibited from using the EDC 
system to generate unnecessary listings/summaries that may introduce unwanted bias or to share 
such outputs from the EDC system with other functions/persons who do not have access to the 
EDC. 
11.9. 
Study Records Retention 
The Investigator must maintain adequate and accurate records to enable the conduct of the study 
to be fully documented and the study data to be subsequently verified. These documents should 

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be classified into at least 1 of the following 2 categories: 1) Investigator’s study file, and/or 2) 
patient clinical source documents. 
The Investigator’s study file will contain the protocol/amendments, eCRF and query forms, 
IRB/IEC and governmental approval with correspondence, informed consent forms, drug 
records, staff curriculum vitae and authorization forms, and other appropriate documents and 
correspondence. 
Patient clinical source documents (usually defined by the project in advance to record key 
efficacy/safety parameters independent of the eCRFs) would include documents such as 
(although not be limited to) the following: patient hospital/clinic records, physician’s and 
nurse’s notes, appointment book, original laboratory reports, ECG, electroencephalogram, 
X-ray, pathology and special assessment reports, consultant letters, screening and enrollment 
logs, etc. 
Following closure of the study, the Investigator must maintain all study records in a safe and 
secure location. The records must be maintained to allow easy and timely retrieval when needed 
(e.g., audit or inspection) and, whenever feasible, to allow any subsequent review of data in 
conjunction with assessment of the facility, supporting systems, and personnel. Where permitted 
by local laws/regulations or institutional policy, some or all of these records can be maintained 
in a format other than hard copy (e.g., microfiche, scanned, electronic); however, caution needs 
to be exercised before such action is taken. The Investigator must ensure that all reproductions 
are legible, are a true and accurate copy of the original, and meet accessibility and retrieval 
standards, including regenerating a hard copy, if required. Furthermore, the Investigator must 
ensure there is an acceptable backup of these reproductions and that an acceptable quality 
control process exists for making these reproductions. 
The Sponsor will inform the Investigator of the time period for retaining these records to 
comply with all applicable regulatory requirements. The minimum retention time will meet the 
strictest standard applicable to that study center for the study, as dictated by any institutional 
requirements, local laws or regulations, or the Sponsor’s standards/procedures; otherwise, the 
retention period will default to 15 years. 
The Investigator must notify the Sponsor of any changes in the archival arrangements, including 
but not limited to the following: archival at an off-site facility, or transfer of ownership of or 
responsibility for the records in the event the Investigator leaves the study center. 
If the Investigator cannot guarantee this archiving requirement at the study site for any or all of 
the documents, special arrangements must be made between the Investigator and Leap 
Therapeutics and BeiGene to store these in sealed containers outside of the site so that they can 
be returned sealed to the Investigator in case of a regulatory audit. When source documents are 
required for the continued care of the patient, appropriate copies should be made for storage 
outside of the site. 
Biological samples at the conclusion of this study may be retained as outlined in the agreement 
with the CRO managing the biological samples, for the shorter of, a period of up to 15 years or 
as allowed by your IRB/IEC. 

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11.10. 
Protocol Deviations 
The Investigator is responsible for ensuring that the study is conducted in accordance with the 
procedures and evaluations described in this protocol. Investigators assert they will apply due 
diligence to avoid protocol deviations and shall report all protocol deviations to the Sponsor. 
The Investigator is to document and explain any deviations from the approved protocol. The 
Investigator must promptly report any major deviations that might impact patient safety and/or 
data integrity to the Sponsor and to the IRB/IEC, in accordance with established IRB/IEC 
policies and procedures. 
11.11. 
Study Report and Publications 
A clinical study report will be prepared and provided to the regulatory agency(ies). BeiGene and 
Leap Therapeutics will ensure that the report meets the standards set out in the ICH Guideline 
for Structure and Content of Clinical Study Reports (ICH E3). Note that an abbreviated report 
may be prepared in certain cases. 
The results of this study will be published or presented at scientific meetings in a timely, 
objective, and clinically meaningful manner that is consistent with good science, industry and 
regulatory guidance and the need to protect the intellectual property of the Sponsor, regardless 
of the outcome of the study. The data generated in this clinical study are the exclusive property 
of the Sponsor and are confidential. As this is a multicenter study, the first publication or 
disclosure of study results shall be a complete, joint multicenter publication or disclosure 
coordinated by the Sponsor. Thereafter, any secondary publications will reference the original 
publication(s). Authorship will be determined by mutual agreement and all authors must meet 
the criteria for authorship established by the International Committee of Medical Journal Editors 
Uniform Requirements for Manuscripts or stricter local criteria (ICMJE 2019). 
Both positive and negative study results will be disclosed. In general, the results of research will 
be submitted for publication to peer-reviewed scientific journals. These journals often do not 
consider negative results for publication. However, results will be otherwise disclosed on 
www.clinicaltrials.gov and other public regulatory websites per regulatory requirement. 
Each Investigator agrees to submit all manuscripts, abstracts, posters, publications, and 
presentations (both oral and written) to the Sponsor for review before submission or 
presentation in accordance with the clinical study agreement. This allows the Sponsor to protect 
proprietary information, provide comments based on information from other studies that may 
not yet be available to the Investigator, and ensure scientific and clinical accuracy. The details 
of the processes of producing and reviewing reports, manuscripts, and presentations based on 
the data from this study will be presented in the Investigator’s clinical study agreement. Each 
Investigator agrees that, in accordance with the terms of the clinical study agreement, a further 
delay of the publication/presentation may be requested by the Sponsor to allow for patent filings 
in advance of the publication/presentation. 
11.12. 
Study Continuation Plan  
Alternative study assessments and/or procedures may be implemented after review and approval 
by the Sponsor under extraordinary circumstances (e.g., pandemic, weather emergency, 
local/national declaration of emergency) to protect patient safety and data quality.  

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11.13. 
Study and Study Center Closure 
Upon completion of the study, the monitor will conduct the following activities in conjunction 
with the Investigator or study center personnel, as appropriate: 
• Return of all study data to the Sponsor 
• Resolution and closure of all data queries 
• Accountability, reconciliation, and arrangements for unused study drug(s) 
• Review of study records for completeness 
• Collection of all study documents for the trial master file filing according to GCP and 
local regulation 
• Shipment of samples (including, but not limited to, those for PK, ADA, and 
biomarkers) to the assay lab for central lab analysis according to protocol and lab 
manual requirements. 
In addition, the Sponsor reserves the right to suspend the enrollment or prematurely discontinue 
this study either at a single study center or at all study centers at any time for any reason. 
Potential reasons for suspension or discontinuation include but are not limited to: safety or 
ethical issues or noncompliance with this protocol, GCP, the Sponsor’s written instructions, the 
clinical study agreement, or applicable laws and regulations. If the Sponsor determines such 
action is needed, the Sponsor will discuss this with the Investigator (including the reasons for 
taking such action) at that time. When feasible, the Sponsor will provide advance notification to 
the Investigator of the impending action before it takes effect. 
The Sponsor will promptly inform all other Investigators and/or institutions conducting the 
study if the study is suspended or terminated for safety reasons. The Sponsor will also inform 
the regulatory authorities of the suspension or termination of the study and the reason(s) for the 
action. If required by applicable regulations, the Investigator must inform the IRB/IEC promptly 
and provide the reason for the suspension or termination. 
If the study is prematurely discontinued, all study data must still be provided to the Sponsor. In 
addition, arrangements will be made for the return of all unused study drug(s) in accordance 
with the applicable Sponsor procedures for the study.  
Financial compensation to the Investigators and/or institutions will be in accordance with the 
clinical study agreement established between the Investigator and/or institutions and the 
Sponsor. 
11.14. 
Information Disclosure and Inventions 
All rights, title, and interests in any inventions, know-how, or other intellectual or industrial 
property rights that are conceived or reduced to practice by the study center personnel during 
the course of or as a result of the study are the sole property of the Sponsor and are hereby 
assigned to the Sponsor. 
If a written contract for the conduct of the study, which includes ownership provisions 
inconsistent with this statement, is executed between the Sponsor and the study center, that 
contract’s ownership provisions shall apply rather than this statement. 

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All information provided by the Sponsor and all data and information generated by the study 
center as part of the study (other than a patient’s medical records) are the sole property of the 
Sponsor and will be kept confidential by the Investigator and other study center personnel. 
This information and data will not be used by the Investigator or other study center personnel 
for any purpose other than conducting the study without the prior written consent of the 
Sponsor. 
These restrictions do not apply to: 
• Information that becomes publicly available through no fault of the Investigator or 
study center personnel 
• Information that is necessary to disclose in confidence to an IRB/IEC solely for the 
evaluation of the study 
• Information that is necessary to disclose to provide appropriate medical care to a 
patient 
• Study results that may be published as described in Section 11.11. 
If a written contract for the conduct of the study, which includes provisions inconsistent with 
this statement is executed, that contract’s provisions shall apply rather than this statement. 

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12. 
REFERENCES 
ACS. Key Statistics About Stomach Cancer. 2020. from 
https://www.cancer.org/cancer/stomach-cancer/about/key-statistics.html. 
Adachi, Y, Yasuda K, et al. Pathology and prognosis of gastric carcinoma: well versus poorly 
differentiated type. Cancer. 2000;89(7): 1418-1424. 
Al-Batran, SE, Hofheinz RD, et al. Histopathological regression after neoadjuvant docetaxel, 
oxaliplatin, fluorouracil, and leucovorin versus epirubicin, cisplatin, and fluorouracil or 
capecitabine in patients with resectable gastric or gastro-oesophageal junction adenocarcinoma 
(FLOT4-AIO): results from the phase 2 part of a multicentre, open-label, randomised phase 2/3 
trial. Lancet Oncol. 2016;17(12): 1697-1708. 
Alderson, D, Cunningham D, et al. Neoadjuvant cisplatin and fluorouracil versus epirubicin, 
cisplatin, and capecitabine followed by resection in patients with oesophageal adenocarcinoma 
(UK MRC OE05): an open-label, randomised phase 3 trial. Lancet Oncol. 2017;18(9): 1249-
1260. 
Ashraf, N, Hoffe S, et al. Locally advanced gastroesophageal junction tumor: a treatment 
dilemma. Oncologist. 2015;20(2): 134-142. 
Bai, Y, Xu N, et al. Tislelizumab in combination with chemotherapy for Chinese patients with 
gastric cancer/gastroesophageal junction adenocarcinoma or esophageal squamous cell 
carcinoma. European Society for Medical Oncology‑Asia. Singapore. 2019. 
Beers, SA, Glennie MJ, et al. Influence of immunoglobulin isotype on therapeutic antibody 
function. Blood. 2016;127(9): 1097-1101. 
Brahmer, J, Lacchetti C, et al. Management of Immune-Related Adverse Events in Patients 
Treated With Immune Checkpoint Inhibitor Therapy: American Society of Clinical Oncology 
Clinical Practice Guideline. J Clin Oncol. 2018;36(17): 1714-1768. 
Bray, F, Ferlay J, et al. Global cancer statistics 2018: GLOBOCAN estimates of incidence and 
mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin. 2018;68(6): 394-424. 
Chao J, Fuchs CS, Shitara K, et al. Assessment of pembrolizumab therapy for the treatment of 
microsatellite instability-high gastric or gastroesophageal junction cancer among patients in the 
KEYNOTE-059, KEYNOTE-061, and KEYNOTE-062 clinical trials. JAMA Oncol 
2021;7:895–902. 
Clevers, H, Loh KM, et al. Stem cell signaling. An integral program for tissue renewal and 
regeneration: Wnt signaling and stem cell control. Science. 2014;346(6205): 1248012. 
Clevers, H and Nusse R. Wnt/beta-catenin signaling and disease. Cell. 2012;149(6): 1192-1205. 
Clopper CJ, Pearson ES. The use of confidence or fiducial limits illustrated in the case of the 
binomial. Biometrika 1934;26:404-413. 

Leap Therapeutics, Inc. 
DEK-DKK1-P205 
Amendment 6, v6.0, 29 June 2023 
Confidential 
151 
CTFG. Recommendations related to contraception and pregnancy testing in clinical trials 
Clinical Trial Facilitation Group. 2014. 
Cunningham, D, Allum WH, et al. Perioperative chemotherapy versus surgery alone for 
resectable gastroesophageal cancer. N Engl J Med. 2006;355(1): 11-20. 
D'Amico, L, Mahajan S, et al. Dickkopf-related protein 1 (Dkk1) regulates the accumulation 
and function of myeloid derived suppressor cells in cancer. The Journal of experimental 
medicine. 2016;213(5): 827-840. 
Dahan, R, Sega E, et al. FcgammaRs Modulate the Anti-tumor Activity of Antibodies Targeting 
the PD-1/PD-L1 Axis. Cancer Cell. 2015;28(3): 285-295. 
Deng, R, Jin F, et al. Monoclonal antibodies: what are the pharmacokinetic and 
pharmacodynamic considerations for drug development? Expert Opin Drug Metab Toxicol. 
2012;8(2): 141-160. 
Deva, S, Lee J, et al. A Phase 1A/1B trial of tislelizumab, an anti-PD-1 antibody, in patients 
with advanced solid tumors. European Society for Medical Oncology. R. Switzer, BeiGene, Ltd. 
2018. 
Dirks, NL and Meibohm B. Population pharmacokinetics of therapeutic monoclonal antibodies. 
Clin Pharmacokinet. 2010;49(10): 633-659. 
Dolgin, M, Association N, et al. Nomenclature and criteria for diagnosis of diseases of the heart 
and great vessels. Boston, Lippincott Williams and Wilkins.1994. 
Ebbinghaus, S. EU Panel Backs Extended Pembrolizumab Dosing Schedule for Single-Agent 
Indications. March 2019. https://www.onclive.com/view/eu-panel-backs-extended-
pembrolizumab-dosing-schedule-for-singleagent-indications. Accessed: 25 May 2022. 
Eisenhauer, EA, Therasse P, et al. New response evaluation criteria in solid tumours: revised 
RECIST guideline (version 1.1). Eur J Cancer. 2009;45(2): 228-247. 
Eloxatin. Eloxatin® (oxaliplatin) prescribing information. Bridgewater, NJ, Sanofi-Aventis U.S. 
LLC. 2015. 
Fenoglio-Preiser, C, Carneiro F, et al. Gastric carcinoma. Pathology and genetics of tumours of 
the digestive system, World Health Organization Classification of Tumours. 2000;1: 35-52. 
Fluorouracil. Fluorouracil injection prescribing information. Spectrum Pharmaceuticals, Inc. 
2016. https://www.accessdata.fda.gov/drugsatfda_docs/label/2016/012209s040lbl.pdf. Accessed 
26 May 2022. 
Fuchs CS, Doi T, et al. Safety and Efficacy of Pembrolizumab Monotherapy in Patients With 
Previously Treated Advanced Gastric and Gastroesophageal Junction Cancer: Phase 2 Clinical 
KEYNOTE-059 Trial. JAMA Oncol. 2018 May 10;4(5):e180013. 

Leap Therapeutics, Inc. 
DEK-DKK1-P205 
Amendment 6, v6.0, 29 June 2023 
Confidential 
152 
Gong, J, Chehrazi-Raffle A, et al. Development of PD-1 and PD-L1 inhibitors as a form of 
cancer immunotherapy: a comprehensive review of registration trials and future considerations. 
J Immunother Cancer. 2018;6(1): 8. 
Gul, N and van Egmond M. Antibody-Dependent Phagocytosis of Tumor Cells by 
Macrophages: A Potent Effector Mechanism of Monoclonal Antibody Therapy of Cancer. 
Cancer Res. 2015;75(23): 5008-5013. 
Haanen, J, Carbonnel F, et al. Management of toxicities from immunotherapy: ESMO Clinical 
Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol. 2017;28(suppl_4): 
iv119-iv142. 
Herskovic, A, Martz K, et al. Combined chemotherapy and radiotherapy compared with 
radiotherapy alone in patients with cancer of the esophagus. N Engl J Med. 1992;326(24): 1593-
1598. 
Holland, P. FDA Accepts Supplemental Biologics License Applications for Pembrolizumab. 
July 2019. https://www.oncozine.com/fda-accepts-supplemental-biologics-license-applications-
for-pembrolizumab/ Accessed: 25 May 2022. 
Hulscher, JB, van Sandick JW, et al. Extended transthoracic resection compared with limited 
transhiatal resection for adenocarcinoma of the esophagus. N Engl J Med. 2002;347(21): 1662-
1669. 
ICMJE. Recommendations for the conduct, reporting, editing, and publication of scholarly work 
in medical journals. 2019. 
Janjigian YY, Shitara K, et al. First-line nivolumab plus chemotherapy versus chemotherapy 
alone for advanced gastric, gastro-oesophageal junction, and oesophageal adenocarcinoma 
(CheckMate 649): a randomised, open-label, phase 3 trial. Lancet. 2021 Jul 3;398(10294):27-
40. 
Kagey, MH and He X. Rationale for Targeting the Wnt Signaling Modulator DKK1 for 
Oncology. Br J Pharmacol. 2017. 
Keizer, RJ, Huitema AD, et al. Clinical pharmacokinetics of therapeutic monoclonal antibodies. 
Clin Pharmacokinet. 2010;49(8): 493-507. 
Kimura, H, Fumoto K, et al. CKAP4 is a Dickkopf1 receptor and is involved in tumor 
progression. J Clin Invest. 2016;126(7): 2689-2705. 
Klempner, S, Bendell J, et al. DKN-01 in combination with pembrolizumab in patients with 
advanced gastroesophageal adenocarcinoma (GEA): Tumoral DKK1 expression as a predictor 
of response and survival. ASCO 2020. 2020. 
Koren, E, Smith HW, et al. Recommendations on risk-based strategies for detection and 
characterization of antibodies against biotechnology products. J Immunol Methods. 2008;333(1-
2): 1-9. 

Leap Therapeutics, Inc. 
DEK-DKK1-P205 
Amendment 6, v6.0, 29 June 2023 
Confidential 
153 
Krause, U, Ryan DM, et al. An unexpected role for a Wnt-inhibitor: Dickkopf-1 triggers a novel 
cancer survival mechanism through modulation of aldehyde-dehydrogenase-1 activity. Cell 
Death Dis. 2014;5: e1093. 
Labrijn, AF, Buijsse AO, et al. Therapeutic IgG4 antibodies engage in Fab-arm exchange with 
endogenous human IgG4 in vivo. Nat Biotechnol. 2009;27(8): 767-771. 
Lala M, Li M, Sinha V, et al. A six-weekly (Q6W) dosing schedule for pembrolizumab based 
on an exposure-response (E-R) evaluation using modeling and simulation. J Clin Onc. 
2018;36(15): 3062. 
Leucovorin Calcium. Leucovorin Calcium For Injection prescribing information.  Bedford 
Laboratories. 2012. 
https://www.accessdata.fda.gov/drugsatfda_docs/label/2012/040347s010lbl.pdf. Accessed: 26 
May 2022. 
Lee, HS, Lee HE, et al. Clinical significance of serum and tissue Dickkopf-1 levels in patients 
with gastric cancer. Clin Chim Acta. 2012a;413(21-22): 1753-1760. 
Levey, AS, Stevens LA, et al. A new equation to estimate glomerular filtration rate. Ann Intern 
Med. 2009;150(9): 604-612. 
Lin, D, Khan U, et al. Gastroesophageal Junction Adenocarcinoma: Is There an Optimal 
Management? Am Soc Clin Oncol Educ Book. 2019;39: e88-e95. 
Liu, QR, Li YF, et al. Prognostic Significance of Dickkopf-1 in Gastric Cancer Survival: A 
Meta-Analysis. Genet Test Mol Biomarkers. 2016;20(4): 170-175. 
Logan, CY and Nusse R. The Wnt signaling pathway in development and disease. Annu Rev 
Cell Dev Biol. 2004;20: 781-810. 
Long GV, Tykodi SS, Schneider JG, et al. Assessment of nivolumab exposure and clinical 
safety of 480 mg every 4 weeks flat-dosing schedule in patients with cancer. Annals of 
Oncology. 2018;29(11):2208-13. 
MacDonald, BT, Tamai K, et al. Wnt/beta-catenin signaling: components, mechanisms, and 
diseases. Developmental cell. 2009;17(1): 9-26. 
Macdonald, JS, Smalley SR, et al. Chemoradiotherapy after surgery compared with surgery 
alone for adenocarcinoma of the stomach or gastroesophageal junction. New England Journal of 
Medicine. 2001;345(10): 725-730. 
Makarova-Rusher, OV, Medina-Echeverz J, et al. The yin and yang of evasion and immune 
activation in HCC. J Hepatol. 2015;62(6): 1420-1429. 
Malladi, S, Macalinao DG, et al. Metastatic Latency and Immune Evasion through Autocrine 
Inhibition of WNT. Cell. 2016;165(1): 45-60. 

Leap Therapeutics, Inc. 
DEK-DKK1-P205 
Amendment 6, v6.0, 29 June 2023 
Confidential 
154 
Merck Press Release. European Medicines Agency Adopts Positive Opinion for Merck’s 
KEYTRUDA® (pembrolizumab) for Six-Week Dosing Schedule Across All Current 
Monotherapy Indications. March 2019. https://www.merck.com/news/european-medicines-
agency-adopts-positive-opinion-for-mercks-keytruda-pembrolizumab-for-six-week-dosing-
schedule-across-all-current-monotherapy-indications/. Accessed: 25 May 2022.  
Merck Press Release. FDA Accepts Merck’s Supplemental Biologics License Applications for 
KEYTRUDA® (pembrolizumab) Six-Week Dosing Schedule for Melanoma and Multiple Other 
Indications. July 2019. https://www.merck.com/news/fda-accepts-mercks-supplemental-
biologics-license-applications-for-keytruda-pembrolizumab-six-week-dosing-schedule-for-
melanoma-and-multiple-other-indications/. Accessed: 25 May 2022. 
Morvan, F, Boulukos K, et al. Deletion of a single allele of the Dkk1 gene leads to an increase 
in bone formation and bone mass. J Bone Miner Res. 2006;21(6): 934-945. 
Mukhopadhyay, M, Shtrom S, et al. Dickkopf1 is required for embryonic head induction and 
limb morphogenesis in the mouse. Dev Cell. 2001;1(3): 423-434. 
Nakamura, K, Ueyama T, et al. Pathology and prognosis of gastric carcinoma. Findings in 
10,000 patients who underwent primary gastrectomy. Cancer. 1992;70(5): 1030-1037. 
NCI. Gastric Cancer Treatment (PDQ®): Health Professional Version. PDQ Cancer 
Information Summaries. Bethesda (MD), National Cancer Institute (US). 2002. 
Niehrs, C. Function and biological roles of the Dickkopf family of Wnt modulators. Oncogene. 
2006;25(57): 7469-7481. 
Oken, MM, Creech RH, et al. Toxicity and response criteria of the Eastern Cooperative 
Oncology Group. Am J Clin Oncol. 1982;5(6): 649-655. 
Omloo, JM, Lagarde SM, et al. Extended transthoracic resection compared with limited 
transhiatal resection for adenocarcinoma of the mid/distal esophagus: five-year survival of a 
randomized clinical trial. Ann Surg. 2007;246(6): 992-1000; discussion 1000-1001. 
OPDIVO. OPDIVO prescribing information. Bristol Myers Squibb.  2014. 
Petrelli, F, Ghidini M, et al. Neoadjuvant chemoradiotherapy or chemotherapy for 
gastroesophageal junction adenocarcinoma: A systematic review and meta-analysis. Gastric 
Cancer. 2019;22(2): 245-254. 
Prieto, J, Melero I, et al. Immunological landscape and immunotherapy of hepatocellular 
carcinoma. Nat Rev Gastroenterol Hepatol. 2015;12(12): 681-700. 
Rawla, P and Barsouk A. Epidemiology of gastric cancer: global trends, risk factors and 
prevention. Prz Gastroenterol. 2019;14(1): 26-38. 

Leap Therapeutics, Inc. 
DEK-DKK1-P205 
Amendment 6, v6.0, 29 June 2023 
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155 
Ribas, A, Puzanov I, et al. Pembrolizumab versus investigator-choice chemotherapy for 
ipilimumab-refractory melanoma (KEYNOTE-002): a randomised, controlled, phase 2 trial. 
Lancet Oncol. 2015;16(8): 908-918. 
Rogers JE, Ajani JA. Defining the role of upfront immune checkpoint inhibition in advanced 
HER-2 negative gastric or gastroesophageal junction adenocarcinoma. Ann Palliat Med. 
2022;11(6):2180-2183. 
Rosenberg, A and Worobec A. A Risk-Based Approach to Immunogenicity Concerns of 
Therapeutic Protein Products, Part 2: Considering Host-Specific and Product-Specific Factors 
Impacting Immunogenicity. BioPharm Intl. 2004;17(12). 
Ryman, JT and Meibohm B. Pharmacokinetics of Monoclonal Antibodies. CPT 
Pharmacometrics Syst Pharmacol. 2017;6(9): 576-588. 
Sasako, M, Sano T, et al. Left thoracoabdominal approach versus abdominal-transhiatal 
approach for gastric cancer of the cardia or subcardia: a randomised controlled trial. Lancet 
Oncol. 2006;7(8): 644-651. 
Sato, N, Yamabuki T, et al. Wnt inhibitor Dickkopf-1 as a target for passive cancer 
immunotherapy. Cancer Res. 2010;70(13): 5326-5336. 
Sedgwick, AE and D'Souza-Schorey C. Wnt Signaling in Cell Motility and Invasion: Drawing 
Parallels between Development and Cancer. Cancers (Basel). 2016;8(9). 
Seymour, L, Bogaerts J, et al. iRECIST: guidelines for response criteria for use in trials testing 
immunotherapeutics. Lancet Oncol. 2017;18(3): e143-e152. 
Shapiro, J, van Lanschot JJB, et al. Neoadjuvant chemoradiotherapy plus surgery versus surgery 
alone for oesophageal or junctional cancer (CROSS): long-term results of a randomised 
controlled trial. Lancet Oncol. 2015;16(9): 1090-1098. 
Shitara K, Van Cutsem E, Bang YJ, et al. Efficacy and safety of pembrolizumab or 
pembrolizumab plus chemotherapy vs chemotherapy alone for patients with first-line, advanced 
gastric cancer: the KEYNOTE-062 phase 3 randomized clinical trial. JAMA Oncol 
2020;6:1571–80. 
Siewert, J, Marcus F, et al. Adenocarcinoma of the esophagogastric junction. Annals of 
Surgery. 2000;232(3): 353-361. 
Siewert, JR, Böttcher K, et al. Relevant prognostic factors in gastric cancer: ten-year results of 
the German Gastric Cancer Study. Annals of Surgery. 1998;228(4): 449-461. 
Smadja, DM, d'Audigier C, et al. The Wnt antagonist Dickkopf-1 increases endothelial 
progenitor cell angiogenic potential. Arterioscler Thromb Vasc Biol. 2010;30(12): 2544-2552. 
Soar, J, Pumphrey R, et al. Emergency treatment of anaphylactic reactions--guidelines for 
healthcare providers. Resuscitation. 2008;77(2): 157-169. 

Leap Therapeutics, Inc. 
DEK-DKK1-P205 
Amendment 6, v6.0, 29 June 2023 
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156 
Tepper, J, Krasna MJ, et al. Phase III trial of trimodality therapy with cisplatin, fluorouracil, 
radiotherapy, and surgery compared with surgery alone for esophageal cancer: CALGB 9781. J 
Clin Oncol. 2008;26(7): 1086-1092. 
Thudi, NK, Martin CK, et al. Dickkopf-1 (DKK-1) stimulated prostate cancer growth and 
metastasis and inhibited bone formation in osteoblastic bone metastases. Prostate. 2011;71(6): 
615-625. 
Verheij, M, Jansen E, et al. A multicenter randomized phase III trial of neo-adjuvant 
chemotherapy followed by surgery and chemotherapy or by surgery and chemoradiotherapy in 
resectable gastric cancer. First results from the CRITICS study (abstract). J Clin Oncol 
2016;34((suppl; abstr 4000)). 
Wagner, AD, Lordick F, et al. Multidisciplinary management of stage II-III gastric and gastro-
oesophageal junction cancer. Eur J Cancer. 2020;124: 67-76. 
Wainberg ZA, Fuchs CS, Tabernero J, et al. Efficacy of pembrolizumabmonotherapy for 
advanced gastric/gastroesophageal junction cancer with programmed death ligand 1 combined 
positive score ≥10. Clin Cancer Res 2021;27:1923–31. 
Wang, J, Sun Y, et al. Comparison of gastric cancer survival between Caucasian and Asian 
patients treated in the United States: results from the Surveillance Epidemiology and End 
Results (SEER) database. Ann Surg Oncol. 2015;22(9): 2965-2971. 
Wang, S and Zhang S. Dickkopf-1 is frequently overexpressed in ovarian serous carcinoma and 
involved in tumor invasion. Clinical & Experimental Metastasis. 2011;28(6): 581-591. 
Weber, JS, D'Angelo SP, et al. Nivolumab versus chemotherapy in patients with advanced 
melanoma who progressed after anti-CTLA-4 treatment (CheckMate 037): a randomised, 
controlled, open-label, phase 3 trial. Lancet Oncol. 2015;16(4): 375-384. 
Wilke H, Muro K, Van Cutsem E, et al. Ramucirumab plus paclitaxel versus placebo plus 
paclitaxel in patients with previously treated advanced gastric or gastro-oesophageal junction 
adenocarcinoma (RAINBOW): a double-blind, randomised phase 3 trial. Lancet Oncol 
2014;15:1224–35. 
Worobec, A and Rosenberg A. A Risk-Based Approach to Immunogenicity Concerns of 
Therapeutic Protein Products, Part 1: Considering Consequences of the Immune Response to a 
Protein. BioPharm Intl. 2004;17(11). 
Wu, C, Budha N, et al. Tislelizumab Exposure-Response Analyses of Efficacy and Safety in 
Patients with Advanced Tumors [ESMO Abstract 482P]. 30. 2019a;Suppl 5(mdz244.044). 
Wu, C, Tang Z, et al. Population Pharmacokinetics of Tislelizumab in Patients with Advanced 
Tumors [ESMO Abstract 483P]. Ann Oncol. 2019b;30(Suppl 5): mdz244.045. 
Wu, C, Zhu Y, et al. Immunohistochemical localization of programmed death-1 ligand-1 (PD-
L1) in gastric carcinoma and its clinical significance. Acta histochemica. 2006;108(1): 19-24. 

Leap Therapeutics, Inc. 
DEK-DKK1-P205 
Amendment 6, v6.0, 29 June 2023 
Confidential 
157 
Xeloda. Xeloda® (capecitabine) prescribing information. South San Francisco, CA, Genentech, 
Inc. 2015. 
Xu, R-h, Arkenau H-T, et al. A phase III trial-in-progress comparing tislelizumab plus 
chemotherapy with placebo plus chemotherapy as first-line therapy in patients with locally 
advanced unresectable or metastatic gastric or gastroesophageal junction (G/GEJ) 
adenocarcinoma. Journal of Clinical Oncology. 2019;37(15_suppl): TPS2655-TPS2655. 
Ychou, M, Boige V, et al. Perioperative chemotherapy compared with surgery alone for 
resectable gastroesophageal adenocarcinoma: an FNCLCC and FFCD multicenter phase III 
trial. J Clin Oncol. 2011;29(13): 1715-1721. 
Zayac, A and Almhanna K. Esophageal, gastric cancer and immunotherapy: small steps in the 
right direction? Translational Gastroenterology and Hepatology. 2019;5. 
Zhang, J, Zhou Y, et al. Evaluation of the seventh AJCC TNM staging system for gastric 
cancer: a meta-analysis of cohort studies. Tumour Biol. 2014;35(9): 8525-8532. 
Zhang, T, Song X, et al. The binding of an anti-PD-1 antibody to FcgammaRIota has a profound 
impact on its biological functions. Cancer Immunol Immunother. 2018;67(7): 1079-1090. 
 

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APPENDIX 1. SCHEDULE OF ASSESSMENTS 
Schedule of Activities – Part A 
Procedure 
Screening1 
Treatment Period 
End-of-
Treatment22 
Safety Follow-
Up22 
PD 
Follow-
up2 
Survival 
Follow-
up3 
 
Unscheduled 
Visits4 
Cycle 1 
 at or after Cycle 2 
C1D1 
C1D15 
D1 
D15 
30 Days Post 
Last Dose 
Q12 
Weeks 
from 
EOT 
Q12 
Weeks 
from 
EOT 
 
 
Days -28 
to 0 
± 3D 
+3D 
±3D 
+7D 
± 14D 
± 14D 
 
Screening informed consent 
X 
 
 
 
 
 
 
 
 
 
Medical history 
X 
 
 
 
 
 
 
 
 
 
Cancer history, including treatment 
history5 and, if available, genomics 
X 
 
 
 
 
 
 
 
 
 
Demographics 
X 
 
 
 
 
 
 
 
 
 
Tumor tissue collection/biopsy 
X6 
 
 
 
 
 
 
 
 
X7 
Height 
X 
 
 
 
 
 
 
 
 
 
Weight 
X 
X 
 
X 
 
X 
X 
 
 
 
Body surface area 
 
X 
 
X 
 
 
 
 
 
 
Vital signs26 
X 
X 
 
X 
 
X 
X 
 
 
X 
Electrocardiogram26 
X 
X9 
 
X 
 
X 
X 
 
 
X 
ECOG performance status 
X 
X 
 
X 
 
X 
X 
 
 
X 
Physical examination 
X 
X25 
 
 
 
X 
X 
 
 
 
Abbreviated physical examination 
 
 
X 
X 
X 
 
 
 
 
X 
Laboratory sample collection: 8 
 
Hematology8 
X 
X9, 25 
X 
X 
X 
X 
X 
 
 
X 
Coagulation 
X 
X25 
 
 
 
X 
X 
 
 
X 
Clinical chemistries8 
X 
X9, 25 
X 
X 
X 
X 
X 
 
 
X 
TSH 
X 
X25 
 
X 
 
X 
X 
 
 
X 
Urinalysis8 
X 
X25 
 
X 
 
X 
X 
 
 
X 
Pregnancy testing10 
X 
X9 
 
X 
 
X 
X 
X 
X 
X 

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Procedure 
Screening1 
Treatment Period 
End-of-
Treatment22 
Safety Follow-
Up22 
PD 
Follow-
up2 
Survival 
Follow-
up3 
 
Unscheduled 
Visits4 
Cycle 1 
 at or after Cycle 2 
C1D1 
C1D15 
D1 
D15 
30 Days Post 
Last Dose 
Q12 
Weeks 
from 
EOT 
Q12 
Weeks 
from 
EOT 
 
 
Days -28 
to 0 
± 3D 
+3D 
±3D 
+7D 
± 14D 
± 14D 
 
   Serum DKK124 
 
pre-dose, 
EOI, 3-12h 
post-dose 
pre-dose, 
EOI, 
3-12h 
post-
dose  
pre-dose, 
EOI  
pre-
dose, 
EOI  
 
X 
 
 
X 
   Serum DKN-01 PK24 
 
pre-dose, 
EOI, 3-12h 
post-dose 
pre-dose, 
EOI, 
3-12h 
post-
dose 
pre-dose, 
EOI 
pre-
dose, 
EOI 
 
X 
 
 
 
   Serum tislelizumab PK 
 
pre-dose 
EOI11 
 
pre-dose 
EOI11 
 
 
X11 
 
 
 
   DKN-01 ADA24 
 
pre-dose 
 
pre-dose 
(every 
ODD 
cycle)23 
 
 
X 
X12 
X12 
 
   Tislelizumab ADA 
 
pre-dose13 
 
pre-dose13 
 
 
X13 
X12 
X12 
 
   ctDNA 
 
pre-dose 
 
 
 
X14 
 
X14 
 
 
Study drug administration15: 
 
DKN-0116 
 
X 
X 
X 
X 
 
 
 
 
 
Tiselelizumab16 
 
X 
 
X 
 
 
 
 
 
 
Oxaliplatin16 
 
X 
 
X 
 
 
 
 
 
 
Capecitabine16 
 
X 
X 
X 
X 
 
 
 
 
 
Baseline head imaging (MRI preferred) 
X 
 
 
 
 
 
 
 
 
 
Tumor imaging17 
X 
 
 
X 
 
X 
 
X 
 
X 
Dispense capecitabine 
 
X 
 
X 
 
 
 
 
 
 
Compliance diary-train/distribute 
 
X 
X 
X 
X 
 
 
 
 
 
Compliance diary-collect/monitor  
 
 
X 
 
X 
X 
 
 
 
 
RECIST disease response assessment18 
 
 
 
X 
 
X 
 
X 
 
 
iRECIST assessment19 
 
 
 
X 
 
X 
 
X 
 
 

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Procedure 
Screening1 
Treatment Period 
End-of-
Treatment22 
Safety Follow-
Up22 
PD 
Follow-
up2 
Survival 
Follow-
up3 
 
Unscheduled 
Visits4 
Cycle 1 
 at or after Cycle 2 
C1D1 
C1D15 
D1 
D15 
30 Days Post 
Last Dose 
Q12 
Weeks 
from 
EOT 
Q12 
Weeks 
from 
EOT 
 
 
Days -28 
to 0 
± 3D 
+3D 
±3D 
+7D 
± 14D 
± 14D 
 
AEs, including infusion-related 
reactions and irAEs20  
X 
X 
X 
X 
X 
X 
X 
 
 
X 
Concomitant medications and 
procedures21 
X 
X 
X 
X 
X 
X 
X 
 
 
X 
Survival and subsequent therapies 
 
 
 
 
 
X 
 
X 
X 
 
Abbreviations: ADA = anti-drug antibodies; AE = adverse event; BID = twice daily; C = cycle; CT = computed tomography; ctDNA = circulating tumor DNA; 
D = day; DKK1 = Dickkopf-1; ECOG = Eastern Cooperative Oncology Group; EBV = Epstein Barr virus; EOI = end of infusion; EOT = end of treatment; 
IEC = independent ethics committee; IHC = immunohistochemistry; irAE = immune-related adverse event; IRB = institutional review board; iRECIST = 
Immune-related Response Evaluation Criteria in Solid Tumors; IV = intravenous; MRI = magnetic resonance imaging; MSI-H/MSI-L = microsatellite instability-
high/low; MSS = microsatellite stable; PD = progressive disease; PD-L1 = programmed cell death ligand 1; PK = pharmacokinetics; PI = Principal Investigator; 
PO = oral; Q12 weeks = once every 12 weeks; RECIST = Response Evaluation Criteria in Solid Tumors; RNA = ribonucleic acid; SAE = serious adverse event; 
TSH = thyroid-stimulating hormone. 
 
Table footnotes: 
1. 
Screening consent must be obtained prior to undergoing any Screening procedures. All Screening assessments must be performed within 28 days before C1D1. The results of 
standard-of-care tests or examinations performed prior to obtaining informed consent and ≤28 days prior to enrollment(C1D1) may be used for the purposes of Screening 
rather than repeating the standard-of-care tests. After completion of all Screening activities, eligibility will be reconfirmed including review of inclusion/exclusion criteria and 
medical history prior to dosing on C1D1. 
2. 
PD Follow-up Period applies only to patients who discontinue study treatment without documented PD. Follow-up assessments will be every 12 weeks (±14 days). 
3. 
All patients will be followed in the Survival Follow-up Period for survival until death, withdrawal of consent, loss to follow-up, or closure of the study by the Sponsor. 
Long-term follow-up will occur 4 times per year (every 12 weeks ±14 days) after the EOT visit or PD Follow-up Period discontinuation visit, as applicable. If a female patient 
is of childbearing potential, she will be followed monthly with a urine pregnancy test up to 6 months following last dose of study drug. This testing can occur at with a 
primary care physician and documentation made available to the study team. Male subjects will be asked during the PD and/or survival follow up period, if their female 
partners have experienced a pregnancy. 
4. 
Unscheduled visits may be performed at any time during the study whenever necessary to assess or follow-up on AEs as deemed necessary by the PI or designee. The PI or 
designee may perform assessments outside of the study schedule (unscheduled visits) for safety purposes based on his/her clinical judgment. Only assessments deemed 
necessary by PI will be performed. The date and reason for the Unscheduled visit should be recorded in the source documentation, including recording of AEs and 
concomitant medications. 
5. 
Cancer treatment history is to include documentation of prior chemotherapy, radiation therapy, surgery, and use of blood products, including red cell and platelet transfusions 
and growth factors within the previous 3 months. 
6. 
Tumor tissue is mandatory. Fresh biopsy is preferred; archived specimen may be acceptable. The tumor tissue will be tested for DKK1 mRNA expression and PD-L1. In 
addition, should sufficient tumor sample be available, the biopsy may be tested for MSS assessment, genomic profiling, RNA profiling (e.g., RNA-Seq), immunohistology, 
EBV, infiltrating immune cells, and additional IHC analysis as applicable. 

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7. 
An additional biopsy to evaluate the effects of treatment on the tumor tissue may be collected at any time during the study if a repeat biopsy is required clinically and the 
patient consents to the biopsy. Patients will be allowed to continue on treatment until they require discontinuation for any reason (i.e., progression, AE) or until a patient 
reaches 2 years of treatment (as measured from C1D1). 
8. 
Refer to Appendix 2. After two years on treatment, safety labs will only be required on Day 1 of each new treatment cycle unless clinically indicated.  
9. 
Hematology, chemistry, pregnancy testing, and ECG must be resulted, and eligibility confirmed prior to dosing. 
10. Serum or urine pregnancy testing is to be performed for women of childbearing potential. If a urine test is positive or cannot be confirmed as negative, a serum pregnancy test 
will be required. Pregnancy testing is to be repeated during the study any time pregnancy is suspected. If a female patient is of childbearing potential, she will be followed 
monthly with a urine pregnancy test up to 6 months following last dose of study drug. This testing can occur at with a primary care physician and documentation made 
available to the study team. Male subjects will be asked during the PD and/or survival follow up period, if their female partners have experienced a pregnancy. 
11. Sampling, handling, and processing procedures are outlined in the Laboratory Manual. Predose (within 60 min before start infusion) samples are required to be collected at 
Day 1 of C1, C2, C5, C9 and C17; post-dose/end of infusion (EOI) (within 30 minutes after completing tislelizumab infusion) samples are required to be collected at Day 1 of 
C1 and C5. An additional PK sample is required to be collected at the Safety Follow-Up Visit. If a patient presents with any immune-related adverse event, additional blood 
PK samples may be taken to determine the concentration of tislelizumab. These tests are required when it is allowed by local regulations/IRBs/IECs. 
12. If a patient has known positive ADA (to DKN-01 or tislelizumab) at the EOT visit, he or she should have repeat testing, where feasible, performed in the PD Follow-up 
Period and/or Survival Follow-up Period until the patient is no longer positive. 
13. Blood used to test for anti-tislelizumab antibodies should be collected within 60 minutes before beginning the Day 1 infusion of C1, C2, C5, C9, and C17 and at the 
mandatory Safety Follow-Up Visit. All samples should be drawn at the same time as blood collection for predose PK analysis. These tests are required when it is allowed by 
local regulations/IRBs/IECs. 
14. ctDNA is to be obtained upon PD (at EOT if discontinuing due to PD, or otherwise in PD follow-up). 
15. Study drug is to be administered in the following order: premedications → DKN-01 → tislelizumab → oxaliplatin → capecitabine (see Section 5.2.2).  
16. DKN-01 will be administered IV over a minimum of 30 minutes and up to a maximum of 2 hours on Days 1 and 15 of each cycle without interruption. Tislelizumab will be 
administered IV over 60 minutes on C1D1 and then over 30 minutes on D1 of each cycle if well tolerated (note: tislelizumab must not be concurrently administered with any 
other drug). Oxaliplatin will be administered IV according to institutional standard of care on Day 1 of each cycle. On Days 1 through 15, the patient will administer 
capecitabine PO twice daily (BID) for a total of 28 doses per cycle. Note: Capecitabine should be taken after food (within 30 minutes of a meal) with water (morning and 
evening) and at the same time each day (±60 minutes).  
17. Baseline imaging studies will be performed within 28 days before C1D1. Results of standard-of-care tests or examinations performed prior to obtaining informed consent and 
≤28 days prior to enrollment may be used for the purposes of Screening rather than repeating the standard-of-care tests. During the study, tumor imaging will be performed 
every 6 weeks (± 7 days), from Cycle 1 Day 1, for the first 24 weeks, then every 9 weeks (± 7 days) after 24 weeks. If a tumor assessment is missed or conducted outside of 
the specified assessment window, all subsequent scans should be conducted on the planned schedule. Screening assessments and each subsequent assessment of the tumor 
must include CT scans (with oral/intravenous contrast, unless contraindicated) or MRI of the chest, abdomen, and pelvis. Other known or suspected sites of disease must be 
included in the imaging assessments (neck, brain, etc.). All measurable and evaluable lesions should be assessed and documented at the Screening Visit and reassessed at each 
subsequent tumor evaluation. The same radiographic procedure used to assess disease sites at Screening is required to be used throughout the study (e.g., the same contrast 
protocol for CT scans).  
18. Disease response is to be assessed every 6 weeks (± 7 days), from Cycle 1 Day 1, for the first 24 weeks, then every 9 weeks (± 7 days) after 24 weeks based on RECIST v1.1. 
After first documentation of response (CR or PR), confirmation of tumor response should occur at a minimum of 4 weeks after the first response or at the next scheduled 
assessment time point. 
19. Tumor response and progression will be assessed by the Investigator using iRECIST, 2017. RECIST v1.1 will be used to determine treatment decisions.  
20. After the patient signs informed consent form for the main study, all safety events that meet the serious criteria will be reported as SAEs. AE collection will begin after the 
administration of study drugs(s). (Note: An SAE narrative will not be required for SAEs that occur prior to study drug administration unless the event was related to a 
protocol mandated procedure). After initiation of study drug, all AEs and SAEs, regardless of relationship to study drug, will be reported until 30 days after last dose of study 
drug(s) (including comparator drug/other IMP) or initiation of new anticancer therapy, whichever occurs first. Reporting will also discontinue if the patient withdraws 
consent. Immune-related AEs (serious or non-serious) should be reported until 90 days after the last dose of DKN-01 and tislelizumab, regardless of whether or not the patient 
starts a new anticancer therapy. All SAEs considered related to the study drug(s) that are brought to the attention of the Investigator should be reported regardless of time 
since the last dose of treatment 
21. At the Screening visit, collect concomitant medications and procedures taken during the last 30 days. 

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22. If the EOT and Safety Follow-up Visits are planned to be conducted within 7 days of one another, the visit procedures from the visits may be combined and completed at the 
EOT visit, and the Safety Follow-up visit may be conducted instead as a telephone call to document AEs and concomitant medications/procedures. Telephone contacts with 
patients also should be conducted to assess immune-related AEs and concomitant medications (if appropriate, i.e., associated with an immune-related AE or is a new 
anticancer therapy) at 60 days and 90 days (± 14 days) after the last dose of study treatment, regardless of whether or not the patient starts a new anticancer therapy. If patients 
report a suspected immune related AE at a telephone follow-up contact, the Investigator should arrange an unscheduled visit if further assessment is indicated. 
23. DKN-01 ADA blood will be collected on C1D1 pre-dose and on all ODD cycles (C3D1pre-dose, C5D1 pre-dose, C7D1 pre-dose, etc). After two years on treatment, DKN-01 
ADA samples will not be collected during routine visits except for at the safety follow visit unless the subject had a known positive ADA at the EOT visit, then they should 
have repeat testing, where feasible, performed in the PD Follow Up and/or Survival Follow Up period until it is no longer positive. 
24. Sample collection windows: Pre-Dose: Samples should be drawn within 60 minutes of the start of the DKN-01 infusion. End of Infusion (EOI): samples should be collected ± 
5 minutes after the end of DKN-01 infusion. 3-12 hr Post-Dose: Samples should be drawn a minimum of 3 hours after the DKN-01 infusion is completed. The sample can be 
drawn up to 12 hours after the DKN-01 sample is complete. After two years on treatment,  DKK1 PK and serum samples will only be required at the safety follow up visit. 
25. May be collected and resulted up to day 2 days prior to C1D1 to confirm eligibility and permit dosing on C1D1  
26. Vital signs and ECG should be performed prior to the collection of laboratory (blood) samples at all visits. 
 
NOTE: All assessments should be performed prior to administration of study drugs (within -2 days) unless stated otherwise. 

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Schedule of Activities – Part B 
Procedure 
 
Pre-
Screening1 Screening2 
Treatment Period 
End-of-
Treatment24 
Safety Follow-
up24 
PD 
Follo
w-up3 
Survival 
Follow-
up4 
 
Unscheduled 
Visits5 
Cycle 1 
≥Cycle 2 
 
 
 
C1D1 
C1D15 
D1 
D15 
30 Days Post 
EOT 
Q12 
Weeks 
from 
EOT 
Q12 
Weeks 
from 
EOT 
 
 
 
Days -28 to 
0 
± 3D 
+ 3D 
± 3D 
+7D 
± 14D 
± 14D 
 
Pre-Screening informed 
consent 
X 
 
 
 
 
 
 
 
 
 
 
Screening informed consent 
 
X 
 
 
 
 
 
 
 
 
 
Medical history 
 
X 
 
 
 
 
 
 
 
 
 
Cancer history, including 
treatment history6 and, if 
available, genomics 
 
X 
 
 
 
 
 
 
 
 
 
Demographics 
 
X 
 
 
 
 
 
 
 
 
 
DKK1 tumor mRNA 
expression7 
X7 
 
 
 
 
 
 
 
 
 
 
Tumor tissue 
collection/biopsy 
X8 
X32 
 
 
 
 
 
 
 
 
X9 
Height 
 
X 
 
 
 
 
 
 
 
 
 
Weight 
 
X 
X 
 
X 
 
X 
X 
 
 
 
Body surface area 
 
 
X 
 
X 
 
 
 
 
 
 
Vital signs31 
 
X 
X 
 
X 
 
X 
X 
 
 
X 
Electrocardiogram31 
 
X 
X11 
 
X 
 
X 
X 
 
 
X 
ECOG performance status 
 
X 
X 
 
X 
 
X 
X 
 
 
X 
Physical examination 
X 
X 
X27 
 
 
 
X 
X 
 
 
 
Abbreviated physical 
examination 
 
 
 
X 
X 
X 
 
 
 
 
X 
Laboratory sample collection: 10 
Hematology10 
 
X 
X11, 27 
X 
X 
X 
X 
X 
 
 
X 
Coagulation 
 
X 
X27 
 
 
 
X 
X 
 
 
X 
Clinical chemistries10 
 
X 
X11, 27 
X 
X 
X 
X 
X 
 
 
X 

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Procedure 
 
Pre-
Screening1 Screening2 
Treatment Period 
End-of-
Treatment24 
Safety Follow-
up24 
PD 
Follo
w-up3 
Survival 
Follow-
up4 
 
Unscheduled 
Visits5 
Cycle 1 
≥Cycle 2 
 
 
 
C1D1 
C1D15 
D1 
D15 
30 Days Post 
EOT 
Q12 
Weeks 
from 
EOT 
Q12 
Weeks 
from 
EOT 
 
 
 
Days -28 to 
0 
± 3D 
+ 3D 
± 3D 
+7D 
± 14D 
± 14D 
 
TSH (Patients in Korea, 
FT3 and FT4 will also be 
assessed) 
 
X 
X27 
 
X 
 
X 
X 
 
 
X 
Urinalysis10 
 
X 
X27 
 
X 
 
X 
X 
 
 
X 
Pregnancy testing12 
 
X 
X11 
 
X 
 
X 
X 
 
 
X 
Serum DKK126 
 
 
pre-
dose, 
EOI, 
3-12h 
post-
dose 
pre-
dose, 
EOI, 
3-12h 
post-
dose 
pre-dose, 
EOI 
pre-
dose, 
EOI 
 
X 
 
 
X 
Serum DKN-01 PK26 
 
 
pre-
dose, 
EOI, 
3-12h 
post-
dose 
pre-
dose, 
EOI, 
3-12h 
post-
dose 
pre-dose, 
EOI 
pre-
dose, 
EOI 
 
X 
 
 
 
Serum tislelizumab PK 
 
 
pre-
dose 
and 
EOI13 
 
pre-dose 
EOI13 
 
 
X13 
 
 
 
DKN-01 ADA26 
 
 
pre-
dose 
 
pre-dose 
(every 
ODD 
cycle)25 
 
 
X 
X14 
X14 
 
Tislelizumab ADA 
 
 
pre-
dose15 
 
pre-dose15 
 
 
X15 
X14 
X14 
 
ctDNA 
 
 
pre-
dose 
 
 
 
X16 
 
X16 
 
 
Study drug administration17: 
DKN-0118 
 
 
X 
X 
X 
X 
 
 
 
 
 

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Procedure 
 
Pre-
Screening1 Screening2 
Treatment Period 
End-of-
Treatment24 
Safety Follow-
up24 
PD 
Follo
w-up3 
Survival 
Follow-
up4 
 
Unscheduled 
Visits5 
Cycle 1 
≥Cycle 2 
 
 
 
C1D1 
C1D15 
D1 
D15 
30 Days Post 
EOT 
Q12 
Weeks 
from 
EOT 
Q12 
Weeks 
from 
EOT 
 
 
 
Days -28 to 
0 
± 3D 
+ 3D 
± 3D 
+7D 
± 14D 
± 14D 
 
tiselelizumab18 
 
 
X 
 
X 
 
 
 
 
 
 
Baseline head imaging (MRI 
preferred) 
 
X 
 
 
 
 
 
 
 
 
X 
Tumor imaging19 
 
X 
 
 
X 
 
X 
 
X 
 
X 
RECIST disease response 
assessment20 
 
 
 
 
X 
 
X 
 
X 
 
 
iRECIST assessment21 
 
 
 
 
X 
 
X 
 
X 
 
 
AEs, including infusion-
related reactions and irAEs22  
X 
X 
X 
X 
X 
X 
X 
X 
 
 
X 
Concomitant medications and 
procedures23 
 
X 
X 
X 
X 
X 
X 
X 
 
 
X 
Survival and subsequent 
therapies 
 
 
 
 
 
 
X 
 
X 
X 
 
Pulmonary Function Tests 
(Korea only) 
 
 
X28 
 
X28 
 
X28 
X28 
 
 
 
FT3 and FT4 (Korea only) 
 
X30 
X30 
 
X30 
 
X30 
X30 
 
 
 
Ophthalmic Examination 
(Korea only) 
 
X29 
 
 
X29 
 
X29 
X29 
 
 
 
Amylase and Lipase (Korea 
only) 
 
X30 
X30 
 
X30 
 
X30 
X30 
 
 
 
Abbreviations: ADA = anti-drug antibodies; AE = adverse event; C = cycle; CT = computed tomography; ctDNA = circulating tumor DNA; D = day; 
DKK1 = Dickkopf-1; ECOG = Eastern Cooperative Oncology Group; EOI = end of infusion; EOT = end of treatment; IEC = independent ethics committee; 
IHC = immunohistochemistry; irAE = immune-related adverse event; IRB = institutional review board; iRECIST = Immune-related Response Evaluation Criteria 
in Solid Tumors; IV = intravenous; MRI = magnetic resonance imaging; MSI-H/MSI-L = microsatellite instability-high/low; MSS = microsatellite stable; 
PD = progressive disease; PD-L1 = programmed cell death ligand 1; PI = Principal Investigator; PK = pharmacokinetics; Q12 weeks = once every 12 weeks; 
RECIST = Response Evaluation Criteria in Solid Tumors; RNA = ribonucleic acid; SAE = serious adverse event; TSH = thyroid-stimulating hormone. 
 

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Table footnotes: 
1. 
Pre-Screening consent must be obtained prior to undergoing DKK1 testing (see footnote 7).  
2. 
To be eligible to proceed with Screening consent, patients must be DKK1-high (see footnote 7). Screening consent must be obtained prior to undergoing any Screening 
procedures. All Screening assessments must be performed within 28 days before C1D1. The results of standard-of-care tests or examinations performed prior to obtaining 
informed consent and ≤28 days prior to enrollment (C1D1) may be used for the purposes of screening rather than repeating the standard-of-care tests. After completion of all 
Screening activities, eligibility will be reconfirmed including review of inclusion/exclusion criteria and medical history prior to dosing on C1D1. 
3. 
PD Follow-up Period applies only to patients who discontinue study treatment without documented PD. Follow-up assessments will be every 12 weeks (±14 days). 
4. 
All patients will be followed in the Survival Follow-up Period for survival until death, withdrawal of consent, loss to follow-up, or closure of the study by the Sponsor. 
Long-term follow-up will occur 4 times per year (every 12 weeks ±14 days) after the 30 days post treatment discontinuation visit or PD Follow-up Period discontinuation 
visit, as applicable. If a female patient is of childbearing potential, she will be followed monthly with a urine pregnancy test up to 6 months following last dose of study drug. 
This testing can occur at with a primary care physician and documentation made available to the study team. Male subjects will be asked during the PD and/or survival follow 
up period, if their female partners have experienced a pregnancy. 
5. 
Unscheduled visits may be performed at any time during the study whenever necessary to assess or follow-up on AEs as deemed necessary by the PI or designee. The PI or 
designee may perform assessments outside of the study schedule (unscheduled visits) for safety purposes based on his/her clinical judgment. Only assessments deemed 
necessary by PI will be performed. The date and reason for the Unscheduled visit should be recorded in the source documentation, including recording of AEs and 
concomitant medications. 
6. 
Cancer treatment history is to include documentation of prior cancer therapies, radiation therapy, surgery, and use of blood products, including red cell and platelet 
transfusions and growth factors within the previous 3 months. 
7. 
Patients must be DKK1-high as determined by elevated DKK1 mRNA expression (H-score ≥35) in tumor cells as defined by CLIA-certified central laboratory testing of a 
fresh biopsy (preferred) or biopsy specimen obtained (See footnote 8). 
8. 
Tumor tissue is mandatory for pre-treatment evaluation. Fresh biopsy is preferred; archived specimen may be acceptable. The tumor tissue will be tested for DKK1 mRNA 
expression to determine eligibility to proceed with Screening (See footnote 7). The tumor biopsy will also be tested for PD-L1, which is not required for eligibility. In 
addition, should sufficient tumor sample be available, the biopsy may be tested for MSS assessment, genomic profiling, RNA profiling (e.g., RNA-Seq), immunohistology, 
EBV, infiltrating immune cells, and additional IHC analysis as applicable. 
9. 
An additional biopsy to evaluate the effects of treatment on the tumor tissue may be collected at any time during the study if a repeat biopsy is required clinically and the 
patient consents to the biopsy. Patients will be allowed to continue on treatment until they require discontinuation for any reason (i.e., progression, AE) or until a patient 
reaches 2 years of treatment (as measured from C1D1). 
10. Refer to Appendix 2. After two years on treatment, safety labs will only be required on Day 1 of each new treatment cycle unless clinically indicated. 
11. Hematology, chemistry, pregnancy testing, and ECG must be resulted, and eligibility confirmed prior to dosing. 
12. Serum or urine pregnancy testing is to be performed for women of childbearing potential. If a urine test is positive or cannot be confirmed as negative, a serum pregnancy test 
will be required. Pregnancy testing is to be repeated during the study any time pregnancy is suspected. If a female patient is of childbearing potential, she will be followed 
monthly with a urine pregnancy test up to 6 months following last dose of study drug. This testing can occur at with a primary care physician and documentation made 
available to the study team. Male subjects will be asked during the PD and/or survival follow up period, if their female partners have experienced a pregnancy. 
13. Sampling, handling, and processing procedures are outlined in the Laboratory Manual. Predose (within 60 min before start infusion) samples are required to be collected at 
Day 1 of C1, C2, C5, C9 and C17; post-dose/ End of Infusion (EOI) (within 30 minutes after completing tislelizumab infusion) samples are required to be collected at Day 1 
of C1 and C5. An additional PK sample is required to be collected at the Safety Follow-Up Visit. If a patient presents with any immune-related adverse event, additional 
blood PK samples may be taken to determine the concentration of tislelizumab. These tests are required when it is allowed by local regulations/IRBs/IECs. 
14. If a patient has known positive ADA (to DKN-01 or tislelizumab) at the EOT visit, he or she should have repeat testing, where feasible, performed in the PD Follow-up 
Period and/or Survival Follow-up Period until the patient is no longer positive. 
15. Blood used to test for anti-tislelizumab antibodies should be collected within 60 minutes before beginning the Day 1 infusion of C1, C2, C5, C9, and C17 and at the 
mandatory Safety Follow-Up Visit. All samples should be drawn at the same time as blood collection for predose PK analysis. These tests are required when it is allowed by 
local regulations/IRBs/IECs. 
16. ctDNA is to be obtained upon PD (at EOT if discontinuing due to PD, or otherwise in PD follow-up). 
17. Study drug is to be administered in the following order: DKN-01 → tislelizumab (see Section 5.2.2). 

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18. DKN-01 will be administered IV over a minimum of 30 minutes and up to a maximum of 2 hours on Days 1 and 15 of each cycle without interruption. Tislelizumab will be 
administered IV over 60 minutes on C1D1 and then over 30 minutes on D1 of each cycle if well tolerated (note: tislelizumab must not be concurrently administered with any 
other drug).  
19. Baseline imaging studies may be performed within 28 days before C1D1. Results of standard-of-care tests or examinations performed prior to obtaining informed consent and 
≤28 days prior to first dose of study drug may be used for the purposes of Screening rather than repeating the standard-of-care tests. During the study, tumor imaging will be 
performed every 6 weeks (± 7 days), from Cycle 1 Day 1, for the first 24 weeks, then every 9 weeks (± 7 days) after 24 weeks. If a tumor assessment is missed or conducted 
outside of the specified assessment window, all subsequent scans should be conducted on the planned schedule. Screening assessments and each subsequent assessment of the 
tumor must include CT scans (with oral/intravenous contrast, unless contraindicated) or MRI of the chest, abdomen, and pelvis. Other known or suspected sites of disease 
must be included in the imaging assessments (neck, brain, etc.). All measurable and evaluable lesions should be assessed and documented at the Screening Visit and 
reassessed at each subsequent tumor evaluation. The same radiographic procedure used to assess disease sites at Screening is required to be used throughout the study (e.g., 
the same contrast protocol for CT scans).  
20. Disease response is to be assessed every 6 weeks (± 7 days), from Cycle 1 Day 1, for the first 24 weeks, then every 9 weeks (± 7 days) after 24 weeks based on RECIST v1.1. 
After first documentation of response (CR or PR), confirmation of tumor response should occur at a minimum of 4 weeks after the first response or at the next scheduled 
assessment time point. 
21. Tumor response and progression will be assessed by the Investigator using the iRECIST, 2017. RECIST v1.1 will be used to determine treatment decisions.  
22. A safety event that occurs during the Pre-screening (Part B Only) Period (i.e., after the patient has signed the informed consent form for Pre-screening but prior to consent for 
the main study), will be reported as an SAE only if the event is related to a protocol-mandated procedure. After the patient signs informed consent form for the main study, all 
safety events that meet the serious criteria will be reported as SAEs. AE collection will begin after the administration of study drugs(s). (Note: An SAE narrative will not be 
required for SAEs that occur prior to study drug administration unless the event was related to a protocol mandated procedure). After initiation of study drug, all AEs and 
SAEs, regardless of relationship to study drug, will be reported until 30 days after last dose of study drug(s) (including comparator drug/other IMP) or initiation of new 
anticancer therapy, whichever occurs first. Reporting will also discontinue if the patient withdraws consent. Immune-related AEs (serious or non-serious) should be reported 
until 90 days after the last dose of DKN-01 and tislelizumab, regardless of whether or not the patient starts a new anticancer therapy. All SAEs considered related to the study 
drug(s) that are brought to the attention of the Investigator should be reported regardless of time since the last dose of treatment 
23. At the Screening visit, collect concomitant medications and procedures taken during the last 30 days. 
24. If the EOT and Safety Follow-up Visits are planned to be conducted within 7 days of one another, the visit procedures from the visits may be combined and completed at the 
EOT visit, and the Safety Follow-up visit may be conducted instead as a telephone call to document AEs and concomitant medications/procedures. Telephone contacts with 
patients also should be conducted to assess immune-related AEs and concomitant medications (if appropriate, i.e., associated with an immune-related AE or is a new 
anticancer therapy) at 60 days and 90 days (± 14 days) after the last dose of study treatment, regardless of whether or not the patient starts a new anticancer therapy. If patients 
report a suspected immune related AE at a telephone follow-up contact, the Investigator should arrange an unscheduled visit if further assessment is indicated. 
25. DKN-01 ADA blood will be collected on C1D1 pre-dose and on all ODD cycles (C3D1pre-dose, C5D1 pre-dose, C7D1pre-dose, etc). After two years on treatment, DKN-01 
ADA samples will not be collected during routine visits except for at the safety follow visit unless the subject had a known positive ADA at the EOT visit, then they should 
have repeat testing, where feasible, performed in the PD Follow Up and/or Survival Follow Up period until it is no longer positive. 
26. Sample collection windows: Pre-Dose: Samples should be drawn within 60 minutes of the start of the DKN-01 infusion. End of Infusion (EOI): samples should be 
collected ± 5 minutes after the end of DKN-01 infusion. 3-12 hr Post-Dose: Samples should be drawn a minimum of 3 hours after the DKN-01 infusion is completed. The 
sample can be drawn up to 12 hours after the DKN-01 sample is complete. After two years on treatment,  DKK1 PK and serum samples will only be required at the safety 
follow up visit. 
27. May be collected and resulted up to day 2 days prior to C1D1 to confirm eligibility and permit dosing on C1D1 
28. Enrolled patients who have a history of radiation pneumonitis will receive Pulmonary Function Tests (PFT) at baseline and every 6 cycles ± 14 days during treatment and 
once either at the end of treatment visit (EOT) or at the Safety Follow-up Visit upon completion of therapy. 
29. The ophthalmic assessments including eye exam, visual acuity test and optical coherence tomography (or equivalent diagnostic test) should be performed during Screening, 
every 6 cycles ± 14 days during treatment and once at either the EOT Visit or Safety Follow-up Visit. 
30. Assessment of Amylase and Lipase and FT3 and FT4 will be conducted at Screening, every 3 cycles (i.e., Day 1 of Cycles 4, 7, 10 etc.) during therapy and once at either the 
EOT Visit or Safety Follow-up Visit 
31. Vital signs and ECG should be performed prior to the collection of laboratory (blood) samples at all visits. 

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32. A fresh biopsy will be collected during the Screening period (+14 days) from patients who did not undergo a biopsy during the Pre-screening period for evaluation of DKK1 
mRNA levels (unless it is clinically contraindicated per Investigator and after consultation with the Medical Monitor) for a retrospective DKK1 mRNA analysis. 
33. Assessment of FT3 and FT4 will be conducted at Screening, every 3 cycles (i.e., Day 1 of Cycles 4, 7, 10 etc.) during therapy and once at either the EOT Visit or Safety 
Follow-up Visit 
NOTE: All assessments should be performed prior to administration of study drugs (within -2 days) unless stated otherwise. 
 

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Schedule of Activities – Part C CAPOX Regimen (21-Day Cycle) 
Procedure 
Screening1 
Treatment Period 
End-of-
Treatment22 
Safety Follow-
Up22 
PD 
Follow-
up2 
Survival 
Follow-up3 
 
Unscheduled 
Visits4 
Cycle 1 
 at or after Cycle 
2 
C1D1 
C1D15 
D1 
30 Days Post 
Last Dose 
Q12 
Weeks 
from 
EOT 
Q12 Weeks 
from EOT 
 
 
Days -28 to 
0 
±3D 
+3D 
+7D 
± 14D 
± 14D 
 
Screening informed consent 
X 
 
 
 
 
 
 
 
 
Medical history 
X 
 
 
 
 
 
 
 
 
Cancer history, including treatment 
history5 and, if available, genomics 
X 
 
 
 
 
 
 
 
 
Demographics 
X 
 
 
 
 
 
 
 
 
Randomization 29 
 
X 
 
 
 
 
 
 
 
Tumor tissue collection/biopsy7 
X6 
 
 
X7 
 
 
 
 
X7 
Height 
X 
 
 
 
 
 
 
 
 
Weight 
X 
X 
X 
X 
X 
X 
 
 
 
Body surface area 
 
X 
 
X 
 
 
 
 
 
Vital signs25 
X 
X 
X 
X 
X 
X 
 
 
X 
Electrocardiogram 25, 9 
X 
X 
 
X 
X 
X 
 
 
X 
ECOG performance status 
X 
X 
 
X 
X 
X 
 
 
X 
Physical examination 
X 
X 
 
 
X 
X 
 
 
 
Abbreviated physical examination 
 
 
 
X 
 
 
 
 
X 
Laboratory sample collection: 
 
Hematology8, 9 
X 
X9 
X 
X 
X 
X 
 
 
X 
Coagulation 
X 
X 
 
 
X 
X 
 
 
X 
Clinical chemistries8, 9 
X 
X9 
X 
X 
X 
X 
 
 
X 
TSH 
X 
X 
 
X 
X 
X 
 
 
X 
Urinalysis8 
X 
X 
 
X 
X 
X 
 
 
X 
Pregnancy testing9,10 
X 
X9 
 
X 
X 
X 
X10 
X10 
X 

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Procedure 
Screening1 
Treatment Period 
End-of-
Treatment22 
Safety Follow-
Up22 
PD 
Follow-
up2 
Survival 
Follow-up3 
 
Unscheduled 
Visits4 
Cycle 1 
 at or after Cycle 
2 
C1D1 
C1D15 
D1 
30 Days Post 
Last Dose 
Q12 
Weeks 
from 
EOT 
Q12 Weeks 
from EOT 
 
 
Days -28 to 
0 
±3D 
+3D 
+7D 
± 14D 
± 14D 
 
   Plasma biomarker Analysis 30 
X 
X 
 
X  
X 
 
 
 
 
Serum biomarker Analysis30 
X 
X 
 
X  
X 
 
 
 
 
   Serum DKK124 
 
pre-dose, 
EOI, 3-
12h post-
dose 
 
pre-dose, EOI  
 
X 
 
 
X 
   Serum DKN-01 PK 31 
 
pre-dose, 
EOI, 3-
12h post-
dose 
 
pre-dose, EOI 
 
X 
 
 
 
   Serum tislelizumab PK11 
 
pre-dose 
EOI 
 
pre-dose EOI 
 
X 
 
 
 
  Serum DKN-01 ADA23 
 
pre-dose 
 
pre-dose (every 
ODD cycle) 
 
X 
X12 
X12 
 
  Serum tislelizumab ADA13 
 
pre-dose 
 
pre-dose 
 
X 
X12 
X12 
 
   ctDNA 
 
pre-dose 
 
 
X14 
 
X14 
 
 
Study drug administration15 
 
DKN-0116 
 
X 
X 
X 
 
 
 
 
 
Tiselelizumab16 
 
X 
 
X 
 
 
 
 
 
Oxaliplatin16 
 
X 
 
X 
 
 
 
 
 
Capecitabine16 
 
X 
 
X 
 
 
 
 
 
Baseline head imaging (MRI 
preferred)17 
X 
 
 
 
 
 
 
 
 
Tumor imaging17 
X 
 
 
X 
X 
 
X 
 
X 
Dispense capecitabine 
 
X 
 
X 
 
 
 
 
 
Compliance diary-train/distribute 
 
X 
 
X 
 
 
 
 
 
Compliance diary-collect/monitor  
 
 
 
X 
X 
 
 
 
 
RECIST disease response 
assessment18 
 
 
 
X 
X 
 
X 
 
X 
iRECIST assessment19 
 
 
 
X 
X 
 
X 
 
 

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Procedure 
Screening1 
Treatment Period 
End-of-
Treatment22 
Safety Follow-
Up22 
PD 
Follow-
up2 
Survival 
Follow-up3 
 
Unscheduled 
Visits4 
Cycle 1 
 at or after Cycle 
2 
C1D1 
C1D15 
D1 
30 Days Post 
Last Dose 
Q12 
Weeks 
from 
EOT 
Q12 Weeks 
from EOT 
 
 
Days -28 to 
0 
±3D 
+3D 
+7D 
± 14D 
± 14D 
 
AEs, including infusion-related 
reactions and irAEs20  
X 
X 
 
X 
X 
X 
 
 
X 
Concomitant medications and 
procedures21 
X 
X 
 
X 
X 
X 
 
 
X 
Survival and subsequent therapies 
 
 
 
 
X 
 
X 
X 
 
Pulmonary Function Tests (Korea 
only) 26 
 
X 
 
X 
X 
X 
 
 
 
FT3 and FT4 (Korea only) 27 
X 
X 
 
X 
X 
X 
 
 
 
Ophthalmic Examination (Korea 
only) 28 
X 
 
 
X 
X 
X 
 
 
 
Amylase and Lipase (Korea only) 27 
X 
X 
 
X 
X 
X 
 
 
 
Abbreviations: ADA = anti-drug antibodies; AE = adverse event; BID = twice daily; C = cycle; CT = computed tomography; ctDNA = circulating tumor DNA; 
D = day; DKK1 = Dickkopf-1; ECOG = Eastern Cooperative Oncology Group; EBV = Epstein Barr virus; EOI = end of infusion; EOT = end of treatment; 
IEC = independent ethics committee; IHC = immunohistochemistry; irAE = immune-related adverse event; IRB = institutional review board; iRECIST = 
Immune-related Response Evaluation Criteria in Solid Tumors; IV = intravenous; MRI = magnetic resonance imaging; MSI-H/MSI-L = microsatellite instability-
high/low; MSS = microsatellite stable; PD = progressive disease; PD-L1 = programmed cell death ligand 1; PK = pharmacokinetics; PI = Principal Investigator; 
PO = oral; Q12 weeks = once every 12 weeks; RECIST = Response Evaluation Criteria in Solid Tumors; RNA = ribonucleic acid; SAE = serious adverse event; 
TSH = thyroid-stimulating hormone. 
 
Table footnotes: 
1. 
Screening consent must be obtained prior to undergoing any Screening procedures. All Screening assessments must be performed within 28 days before C1D1 (except 
imaging which can be within 35 days). The results of standard-of-care tests or examinations performed prior to obtaining informed consent and ≤28 days prior to enrollment 
(C1D1) may be used for the purposes of screening rather than repeating the standard-of-care tests. Safety labs and physical exam must be performed within 3 days prior to 
dosing on C1D1 to confirm patient still meets treatment and eligibility criteria. 
2. 
PD Follow-up Period applies only to patients who discontinue study treatment without documented PD. Follow-up assessments will be every 12 weeks (±14 days). 
3. 
All patients will be followed in the Survival Follow-up Period for survival until death, withdrawal of consent, loss to follow-up, or closure of the study by the Sponsor. 
Long-term follow-up will occur every 12 weeks ±14 days after the EOT visit or PD Follow-up Period discontinuation visit, as applicable. If a female patient is of childbearing 
potential, she will be followed monthly with a urine pregnancy test up to 6 months following last dose of study drug. This testing can occur at with a primary care physician 
and documentation made available to the study team. Male subjects will be asked during the PD and/or survival follow up period, if their female partners have experienced a 
pregnancy. 

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4. 
Unscheduled visits may be performed at any time during the study whenever necessary to assess or follow-up on Aes as deemed necessary by the PI or designee. The PI or 
designee may perform assessments outside of the study schedule (unscheduled visits) for safety purposes based on his/her clinical judgment. Only assessments deemed 
necessary by PI will be performed. The date and reason for the Unscheduled visit should be recorded in the source documentation, including recording of Aes and 
concomitant medications. 
5. 
Cancer treatment history is to include documentation of prior cancer therapies, radiation therapy, surgery, and use of blood products, including red cell and platelet 
transfusions and growth factors within the previous 3 months. 
6. 
Tumor tissue is mandatory. Fresh biopsy is preferred; archived specimen may be acceptable. The tumor tissue will be tested for DKK1 mRNA expression and PD-L1. In 
addition, should sufficient tumor sample be available, the biopsy may be tested for MSS assessment, genomic profiling, RNA profiling (e.g., RNA-Seq), immunohistology, 
EBV, infiltrating immune cells, and additional IHC analysis as applicable. 
7. 
An on-treatment biopsy to evaluate the effects of treatment on the tumor tissue is required at Day 21 (+7 days) unless clinically not feasible. An additional biopsy may be 
collected at any other time during the study if a repeat biopsy is required clinically and the patient consents to the biopsy. Patients will be allowed to continue on-treatment 
until they require discontinuation for any reason (i.e., progression, AE) or until a patient reaches 2 years of treatment (as measured from C1D1). 
8. 
Refer to Appendix 2. After two years on treatment, safety labs will only be required on Day 1 of each new treatment cycle unless clinically indicated. 
9. 
Hematology, chemistry, pregnancy testing, and ECG must be performed, within 3 days prior to dosing at each cycle, to confirm patient meets requirements to receive study 
drug treatment. 
10. Serum or urine pregnancy testing is to be performed for women of childbearing potential. If a urine test is positive or cannot be confirmed as negative, a serum pregnancy test 
will be required. Pregnancy testing is to be repeated during the study any time pregnancy is suspected. If a female patient is of childbearing potential, she will be followed 
monthly with a urine pregnancy test up to 6 months following the last dose of study drug. This testing can occur at with a primary care physician and documentation made 
available to the study team. Male subjects will be asked during the PD and/or survival follow up period, if their female partners have experienced a pregnancy. 
11. Sampling, handling, and processing procedures are outlined in the Laboratory Manual. Predose (prior to the start of infusion) samples are required to be collected at Day 1 of 
C1, C2, C5, C9 and C17; post-dose/end of infusion (EOI) (within 30 minutes after completing tislelizumab infusion) samples are required to be collected at Day 1 of C1 and 
C5. An additional PK sample is required to be collected at the Safety Follow-Up Visit. If a patient presents with any immune-related adverse event, additional blood PK 
samples may be taken to determine the concentration of tislelizumab. These tests are required when it is allowed by local regulations/IRBs/IECs. 
12. If a patient has known positive ADA (to DKN-01 [experimental group only] or tislelizumab) at the EOT visit, he or she should have repeat testing, where feasible, performed 
in the PD Follow-up Period and/or Survival Follow-up Period until the patient is no longer positive. 
13. Blood used to test for anti-tislelizumab antibodies should be collected before beginning the Day 1 infusion of C1, C2, C5, C9, and C17 and at the mandatory Safety Follow-
Up Visit. All samples should be drawn at the same time as blood collection for predose PK analysis. These tests are required when it is allowed by local 
regulations/IRBs/IECs. 
14. ctDNA is to be obtained upon PD (at EOT if discontinuing due to PD, or otherwise in PD follow-up). 
15. Study drug is to be administered in the following order: premedications → DKN-01 (experimental group only) → tislelizumab → chemotherapy (see Section 5.2.2).  
16. Patients in the experimental group will receive DKN-01 (600 mg, IV) and tislelizumab (200 mg, IV) on Day 1 of each 21-day cycle. For Cycle 1 only, an additional loading 
dose of DKN-01 (600 mg, IV) will be administered on Day 15. The CAPOX regimen will include oxaliplatin on Day 1 and capecitabine BID on Days 1-15 (for a total of 28 
doses) of each 21-day cycle. Patients in the control group will follow the same administration order for tislelizumab and CAPOX but will not receive DKN-01 treatment. 
Note: Capecitabine should be taken after food (within 30 minutes of a meal) with water (morning and evening) and at the same time each day (±60 minutes). Chemotherapy 
dosing is to be administered per institutional standard of care. 
17. Baseline imaging studies will be performed within 35 days of C1D1. Results of standard-of-care tests or examinations performed prior to obtaining informed consent and ≤28 
days prior to enrollment may be used for the purposes of screening rather than repeating the standard-of-care tests. During the study, tumor imaging will be performed every 6 
weeks (± 7 days), from Cycle 1 Day 1, for the first 24 weeks, then every 9 weeks (± 7 days) after 24 weeks. If a tumor assessment is missed or conducted outside of the 
specified assessment window, all subsequent scans should be conducted on the planned schedule. Screening assessments and each subsequent assessment of the tumor must 
include CT scans (with oral/intravenous contrast, unless contraindicated) or MRI of the chest, abdomen, and pelvis. Other known or suspected sites of disease must be 
included in the imaging assessments (neck, brain, etc.). All measurable and evaluable lesions should be assessed and documented at the Screening Visit and reassessed at each 
subsequent tumor evaluation. The same radiographic procedure used to assess disease sites at Screening is required to be used throughout the study (e.g., the same contrast 
protocol for CT scans).  

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18. Disease response is to be assessed every 6 weeks (± 7 days), from Cycle 1 Day 1, for the first 24 weeks, then every 9 weeks (± 7 days) after 24 weeks based on RECIST v1.1. 
After first documentation of response (CR or PR), confirmation of tumor response should occur at a minimum of 4 weeks after the first response or at the next scheduled 
assessment time point. 
19. Following progression using RECIST 1.1, tumor response and progression will be assessed by the Investigator using iRECIST, 2017. RECIST v1.1 will be used to determine 
treatment decisions.  
20. After the patient signs informed consent form for the study, all safety events that meet the serious criteria will be reported as SAEs. AE collection will begin after the 
administration of study drugs(s). (Note: An SAE narrative will not be required for SAEs that occur prior to study drug administration unless the event was related to a 
protocol mandated procedure). After initiation of study drug, all Aes and SAEs, regardless of relationship to study drug, will be reported until 30 days after last dose of study 
drug(s) (including comparator drug/other IMP) or initiation of new anticancer therapy, whichever occurs first. Reporting will also discontinue if the patient withdraws 
consent. Immune-related Aes (serious or non-serious) should be reported until 90 days after the last dose of DKN-01 and tislelizumab, regardless of whether or not the patient 
starts a new anticancer therapy. All SAEs considered related to the study drug(s) that are brought to the attention of the Investigator should be reported regardless of time 
since the last dose of treatment 
21. At the Screening visit, collect concomitant medications and procedures taken during the last 30 days. 
22. If the EOT and Safety Follow-up Visits are planned to be conducted within 7 days of one another, the visit procedures from the visits may be combined and completed at the 
EOT visit, and the Safety Follow-up visit may be conducted instead as a telephone call to document Aes and concomitant medications/procedures. Telephone contacts with 
patients also should be conducted to assess immune-related Aes and concomitant medications (if appropriate, i.e., associated with an immune-related AE or is a new 
anticancer therapy) at 60 days and 90 days (± 14 days) after the last dose of study treatment, regardless of whether or not the patient starts a new anticancer therapy. If patients 
report a suspected immune related AE at a telephone follow-up contact, the Investigator should arrange an unscheduled visit if further assessment is indicated. 
23. Experimental group only: DKN-01 ADA blood will be collected on C1D1 pre-dose and on all ODD cycles (C3D1pre-dose, C5D1 pre-dose, C7D1 pre-dose, etc). If a patient 
has known positive ADA at the EOT visit, repeat testing, where feasible, will be performed in the PD Follow-up Period and/or Survival Follow-up Period until the patient is 
no longer positive. After two years on treatment, DKN-01 ADA samples will not be collected during routine visits except for at the safety follow visit unless the subject had a 
known positive ADA at the EOT visit, then they should have repeat testing, where feasible, performed in the PD Follow Up and/or Survival Follow Up period until it is no 
longer positive. 
24. Sample collection windows for the experimental group: Pre-Dose: Samples should be drawn prior to the start of the DKN-01 infusion. End of Infusion (EOI): samples 
should be collected ± 5 minutes after the end of DKN-01 infusion. 3-12 hr Post-Dose: Samples should be drawn a minimum of 3 hours after the DKN-01 infusion is 
completed. The sample can be drawn up to 12 hours after the DKN-01 infusion sample is complete. After two years on treatment, DKK1 PK and serum samples will only be 
required at the safety follow up visit. Sample collection windows for the control group: Only Pre-Dose sample collection is required. Samples should be drawn prior to the 
start of treatment. 
25. Vital signs and ECG should be performed prior to the collection of laboratory (blood) samples at all visits if possible per sites standard process. 
26. Enrolled patients who have a history of radiation pneumonitis will receive Pulmonary Function Tests (PFT) at C1D1 and every 6 cycles ± 14 days during treatment and once 
either at the end of treatment visit (EOT) or at the Safety Follow-up Visit upon completion of therapy. 
27. Assessment of Amylase and Lipase and FT3 and FT4 will be conducted at Screening, every 3 cycles (i.e., Day 1 of Cycles 1, 4, 7, 10 etc.) during therapy and once at either 
the EOT Visit or Safety Follow-up Visit 
28. The ophthalmic assessments including eye exam, visual acuity test and optical coherence tomography (or equivalent diagnostic test) should be performed during Screening, 
every 6 cycles ± 14 days during treatment and once at either the EOT Visit or Safety Follow-up Visit. 
29. Randomization may occur up to 3 days prior to C1D1 as long as safety labs for dosing are resulted.  
30. Sampling, handling, and processing procedures are outlined in the Laboratory Manual for plasma and serum biomarker analysis. Samples are required to be collected at 
Screening and pre-dose at Day 1 of C1, C2, C3, and EOT. 
31. Sample collection windows for the experimental group only: Pre-Dose: Samples should be drawn prior to the start of the DKN-01 infusion. End of Infusion (EOI): 
samples should be collected ± 5 minutes after the end of DKN-01 infusion. 3-12 hr Post-Dose: Samples should be drawn a minimum of 3 hours after the DKN-01 infusion is 
completed. The sample can be drawn up to 12 hours after the DKN-01 infusion sample is complete. After two years on treatment, DKK1 PK and serum samples will only be 
required at the safety follow up visit. 
NOTE: All assessments should be performed prior to administration of study drugs (within -2 days) unless stated otherwise. 

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Schedule of Activities – Part C mFOLFOX6 Regimen (14-Day Cycle) 
Procedure 
Screening1 
Treatment Period 
End-of-
Treatment22 
Safety Follow-
Up22 
PD 
Follow-
up2 
Survival 
Follow-
up3 
 
Unscheduled 
Visits4 
Cycle 1 
 at or after Cycle 2 
C1D1 
C1D8 
D1 
30 Days Post 
Last Dose 
Q12 
Weeks 
from 
EOT 
Q12 
Weeks 
from 
EOT 
 
 
Days -28 
to 0 
±3D 
+3D 
+7D 
± 14D 
± 14D 
 
Screening informed consent 
X 
 
 
 
 
 
 
 
 
Medical history 
X 
 
 
 
 
 
 
 
 
Cancer history, including treatment 
history5 and, if available, genomics 
X 
 
 
 
 
 
 
 
 
Demographics 
X 
 
 
 
 
 
 
 
 
Randmization29 
 
X 
 
 
 
 
 
 
 
Tumor tissue collection/biopsy7 
X6 
 
 
X7 
 
 
 
 
X7 
Height 
X 
 
 
 
 
 
 
 
 
Weight 
X 
X 
X 
X 
X 
X 
 
 
 
Body surface area 
 
X 
 
X 
 
 
 
 
 
Vital signs25 
X 
X 
X 
X 
X 
X 
 
 
X 
Electrocardiogram25, 9 
X 
X 
 
X 
X 
X 
 
 
X 
ECOG performance status 
X 
X 
 
X 
X 
X 
 
 
X 
Physical examination 
X 
X 
 
 
X 
X 
 
 
 
Abbreviated physical examination 
 
 
 
X 
 
 
 
 
X 
Laboratory sample collection: 
 
Hematology8,9 
X 
X9 
X 
X 
X 
X 
 
 
X 
Coagulation 
X 
X 
 
 
X 
X 
 
 
X 
Clinical chemistries8, 9 
X 
X9 
X 
X 
X 
X 
 
 
X 
TSH 
X 
X 
 
X 
X 
X 
 
 
X 
Urinalysis8 
X 
X 
 
X 
X 
X 
 
 
X 
Pregnancy testing9,10 
X 
X9 
 
X 
X 
X 
X10 
X10 
X 

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Procedure 
Screening1 
Treatment Period 
End-of-
Treatment22 
Safety Follow-
Up22 
PD 
Follow-
up2 
Survival 
Follow-
up3 
 
Unscheduled 
Visits4 
Cycle 1 
 at or after Cycle 2 
C1D1 
C1D8 
D1 
30 Days Post 
Last Dose 
Q12 
Weeks 
from 
EOT 
Q12 
Weeks 
from 
EOT 
 
 
Days -28 
to 0 
±3D 
+3D 
+7D 
± 14D 
± 14D 
 
   Plasma biomarker Analysis30 
X 
X 
 
X  
X 
 
 
 
 
   Serum biomarker Analysis30 
X 
X 
 
X  
X 
 
 
 
 
   Serum DKK124 
 
pre-dose, 
EOI, 3-
12h post-
dose 
 
pre-dose, EOI  
 
X 
 
 
X 
   Serum DKN-01 PK 31 
 
pre-dose, 
EOI, 3-
12h post-
dose 
 
pre-dose, EOI 
 
X 
 
 
 
   Serum tislelizumab PK 11 
 
pre-dose 
EOI 
 
pre-dose EOI 
 
X 
 
 
 
   Serum DKN-01 ADA23 
 
pre-dose 
 
pre-dose (every 
ODD cycle) 
 
X 
X12 
X12 
 
   Serum tislelizumab ADA13 
 
pre-dose 
 
pre-dose 
 
X 
X12 
X12 
 
   ctDNA 
 
pre-dose 
 
 
X14 
 
X14 
 
 
Study drug administration15: 
 
DKN-0116 
 
X 
X 
X 
 
 
 
 
 
Tiselelizumab16 
 
X 
 
X 
 
 
 
 
 
Leucovorin calcium 16 
 
X 
 
X 
 
 
 
 
 
Fluorouracil16 
 
X 
 
X 
 
 
 
 
 
  Oxaliplatin16 
 
X 
 
X 
 
 
 
 
 
Baseline head imaging (MRI 
preferred)17 
X 
 
 
 
 
 
 
 
 
Tumor imaging17 
X 
 
 
X 
X 
 
X 
 
X 
RECIST disease response assessment18 
 
 
 
X 
X 
 
X 
 
X 
iRECIST assessment19 
 
 
 
X 
X 
 
X 
 
 
AEs, including infusion-related 
reactions and irAEs20  
X 
X 
 
X 
X 
X 
 
 
X 

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Procedure 
Screening1 
Treatment Period 
End-of-
Treatment22 
Safety Follow-
Up22 
PD 
Follow-
up2 
Survival 
Follow-
up3 
 
Unscheduled 
Visits4 
Cycle 1 
 at or after Cycle 2 
C1D1 
C1D8 
D1 
30 Days Post 
Last Dose 
Q12 
Weeks 
from 
EOT 
Q12 
Weeks 
from 
EOT 
 
 
Days -28 
to 0 
±3D 
+3D 
+7D 
± 14D 
± 14D 
 
Concomitant medications and 
procedures21 
X 
X 
 
X 
X 
X 
 
 
X 
Survival and subsequent therapies 
 
 
 
 
X 
 
X 
X 
 
Pulmonary Function Tests (Korea only) 
26 
 
X 
 
X 
X 
X 
 
 
 
FT3 and FT4 (Korea only)27 
X 
X 
 
X 
X 
X 
 
 
 
Ophthalmic Examination (Korea 
only)28 
X 
 
 
X 
X 
X 
 
 
 
Amylase and Lipase (Korea only)27 
X 
X 
 
X 
X 
X 
 
 
 
Abbreviations: ADA = anti-drug antibodies; AE = adverse event; BID = twice daily; C = cycle; CT = computed tomography; ctDNA = circulating tumor DNA; 
D = day; DKK1 = Dickkopf-1; ECOG = Eastern Cooperative Oncology Group; EBV = Epstein Barr virus; EOI = end of infusion; EOT = end of treatment; 
IEC = independent ethics committee; IHC = immunohistochemistry; irAE = immune-related adverse event; IRB = institutional review board; iRECIST = 
Immune-related Response Evaluation Criteria in Solid Tumors; IV = intravenous; MRI = magnetic resonance imaging; MSI-H/MSI-L = microsatellite instability-
high/low; MSS = microsatellite stable; PD = progressive disease; PD-L1 = programmed cell death ligand 1; PK = pharmacokinetics; PI = Principal Investigator; 
PO = oral; Q12 weeks = once every 12 weeks; RECIST = Response Evaluation Criteria in Solid Tumors; RNA = ribonucleic acid; SAE = serious adverse event; 
TSH = thyroid-stimulating hormone. 
 
Table footnotes: 
1. 
Screening consent must be obtained prior to undergoing any Screening procedures. All Screening assessments must be performed within 28 days before C1D1 (except 
imaging which can be within 35 days). The results of standard-of-care tests or examinations performed prior to obtaining informed consent and ≤28 days prior to enrollment 
(C1D1) may be used for the purposes of screening rather than repeating the standard-of-care tests. Safety labs and physical exam must be performed within 3 days prior to 
dosing on C1D1 to confirm patient still meets treatment and eligibility criteria. 
2. 
PD Follow-up Period applies only to patients who discontinue study treatment without documented PD. Follow-up assessments will be every 12 weeks (±14 days). 
3. 
All patients will be followed in the Survival Follow-up Period for survival until death, withdrawal of consent, loss to follow-up, or closure of the study by the Sponsor. 
Long-term follow-up will occur every 12 weeks ±14 days after the EOT visit or PD Follow-up Period discontinuation visit, as applicable. If a female patient is of childbearing 
potential, she will be followed monthly with a urine pregnancy test up to 6 months following the last dose of study drug. This testing can occur at with a primary care 
physician and documentation made available to the study team. Male subjects will be asked during the PD and/or survival follow up period, if their female partners have 
experienced a pregnancy. 
4. 
Unscheduled visits may be performed at any time during the study whenever necessary to assess or follow-up on AEs as deemed necessary by the PI or designee. The PI or 
designee may perform assessments outside of the study schedule (unscheduled visits) for safety purposes based on his/her clinical judgment. Only assessments deemed 
necessary by PI will be performed. The date and reason for the Unscheduled visit should be recorded in the source documentation, including recording of AEs and 
concomitant medications. 

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5. 
Cancer treatment history is to include documentation of prior cancer therapies, radiation therapy, surgery, and use of blood products, including red cell and platelet 
transfusions and growth factors within the previous 3 months. 
6. 
Tumor tissue is mandatory. Fresh biopsy is preferred; archived specimen may be acceptable. The tumor tissue will be tested for DKK1 mRNA expression and PD-L1. In 
addition, should sufficient tumor sample be available, the biopsy may be tested for MSS assessment, genomic profiling, RNA profiling (e.g., RNA-Seq), immunohistology, 
EBV, infiltrating immune cells, and additional IHC analysis as applicable. 
7. 
An on-treatment biopsy to evaluate the effects of treatment on the tumor tissue is required at Day 21 (+7 days). An additional biopsy may be collected at any other time during 
the study if a repeat biopsy is required clinically and the patient consents to the biopsy. Patients will be allowed to continue on-treatment until they require discontinuation for 
any reason (i.e., progression, AE) or until a patient reaches 2 years of treatment (as measured from C1D1). 
8. 
Refer to Appendix 2. After two years on treatment, safety labs will only be required on Day 1 of each new treatment cycle unless clinically indicated. 
9. 
Hematology, chemistry, pregnancy testing, and ECG must be performed within 3 days prior to dosing at each cycle, to confirm patient meets requirements to receive study 
drug treatment. 
10. Serum or urine pregnancy testing is to be performed for women of childbearing potential. If a urine test is positive or cannot be confirmed as negative, a serum pregnancy test 
will be required. Pregnancy testing is to be repeated during the study any time pregnancy is suspected. If a female patient is of childbearing potential, she will be followed 
monthly with a urine pregnancy test up to 6 months following the last dose of study drug. This testing can occur at with a primary care physician and documentation made 
available to the study team. Male subjects will be asked during the PD and/or survival follow up period, if their female partners have experienced a pregnancy. 
11. Sampling, handling, and processing procedures are outlined in the Laboratory Manual. Predose (prior to the start of infusion) samples are required to be collected at Day 1 of 
C1, C4, C7, C13 and C25and EOT/Safety Follow-up; post-dose/end of infusion (EOI) (within 30 minutes after completing tislelizumab infusion) samples are required to be 
collected at Day 1 of C1, C7, and 30 days ± 7days after the last dose. An additional PK sample is required to be collected at the Safety Follow-Up Visit. If a patient presents 
with any immune-related adverse event, additional blood PK samples may be taken to determine the concentration of tislelizumab. These tests are required when it is allowed 
by local regulations/IRBs/IECs. 
12. If a patient has known positive ADA (to DKN-01 or tislelizumab) at the EOT visit, he or she should have repeat testing, where feasible, performed in the PD Follow-up 
Period and/or Survival Follow-up Period until the patient is no longer positive. 
13. Blood used to test for anti-tislelizumab antibodies should be collected before beginning the Day 1 infusion of C1, C4, C7, C13 and C25 and at the mandatory Safety Follow-
Up Visit. All samples should be drawn at the same time as blood collection for predose PK analysis. These tests are required when it is allowed by local 
regulations/IRBs/IECs. 
14. ctDNA is to be obtained upon PD (at EOT if discontinuing due to PD, or otherwise in PD follow-up). 
15. Study drug is to be administered in the following order: premedications → DKN-01 (experimental group only) → tislelizumab followed by chemotherapy (see Section 5.2.2).  
16. Patients in the experimental group will receive DKN-01 (400 mg, IV) on D1 of each 14-day cycle and tislelizumab (400 mg, IV) will be administered every 6 weeks starting 
on C1D1 and continuing every third 14-day cycle (e.g., C4D1, C7D1, etc). For Cycle 1 only, an additional loading dose of DKN-01 (400 mg, IV) will be administered on Day 
8. The mFOLFOX6 regimen will be administered every 14 days and may include leucovorin calcium (folinic acid) IV on Day 1, fluorouracil IV bolus on Day 1, then 
fluorouracil IV/day (Days 1 and 2), and oxaliplatin IV on Day 1. Patients in the control group will follow the same administration order for tislelizumab and mFOLFOX6 but 
will not receive DKN-01 treatment. Chemotherapy dosing is to be administered per institutional standard of care. 
17. Baseline imaging studies will be performed within 35 days before C1D1. Results of standard-of-care tests or examinations performed prior to obtaining informed consent and 
≤28 days prior to enrollment may be used for the purposes of screening rather than repeating the standard-of-care tests. During the study, tumor imaging will be performed 
every 6 weeks (± 7 days), from Cycle 1 Day 1, for the first 24 weeks, then every 9 weeks (± 7 days) after 24 weeks. If a tumor assessment is missed or conducted outside of 
the specified assessment window, all subsequent scans should be conducted on the planned schedule. Screening assessments and each subsequent assessment of the tumor 
must include CT scans (with oral/intravenous contrast, unless contraindicated) or MRI of the chest, abdomen, and pelvis. Other known or suspected sites of disease must be 
included in the imaging assessments (neck, brain, etc.). All measurable and evaluable lesions should be assessed and documented at the Screening Visit and reassessed at each 
subsequent tumor evaluation. The same radiographic procedure used to assess disease sites at Screening is required to be used throughout the study (e.g., the same contrast 
protocol for CT scans).  
18. Disease response is to be assessed every 6 weeks (± 7 days), from Cycle 1 Day 1, for the first 24 weeks, then every 9 weeks (± 7 days) after 24 weeks based on RECIST v1.1. 
After first documentation of response (CR or PR), confirmation of tumor response should occur at a minimum of 4 weeks after the first response or at the next scheduled 
assessment time point. 
19. Following progression using RECIST 1.1, tumor response and progression will be assessed by the Investigator using iRECIST, 2017. RECIST v1.1 will be used to determine 
treatment decisions.  

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20. After the patient signs informed consent form for the main study, all safety events that meet the serious criteria will be reported as SAEs. AE collection will begin after the 
administration of study drugs(s). (Note: An SAE narrative will not be required for SAEs that occur prior to study drug administration unless the event was related to a 
protocol mandated procedure). After initiation of study drug, all AEs and SAEs, regardless of relationship to study drug, will be reported until 30 days after last dose of study 
drug(s) (including comparator drug/other IMP) or initiation of new anticancer therapy, whichever occurs first. Reporting will also discontinue if the patient withdraws 
consent. Immune-related AEs (serious or non-serious) should be reported until 90 days after the last dose of DKN-01 and tislelizumab, regardless of whether or not the patient 
starts a new anticancer therapy. All SAEs considered related to the study drug(s) that are brought to the attention of the Investigator should be reported regardless of time 
since the last dose of treatment 
21. At the Screening visit, collect concomitant medications and procedures taken during the last 30 days. 
22. If the EOT and Safety Follow-up Visits are planned to be conducted within 7 days of one another, the visit procedures from the visits may be combined and completed at the 
EOT visit, and the Safety Follow-up visit may be conducted instead as a telephone call to document AEs and concomitant medications/procedures. Telephone contacts with 
patients also should be conducted to assess immune-related AEs and concomitant medications (if appropriate, i.e., associated with an immune-related AE or is a new 
anticancer therapy) at 60 days and 90 days (± 14 days) after the last dose of study treatment, regardless of whether or not the patient starts a new anticancer therapy. If patients 
report a suspected immune related AE at a telephone follow-up contact, the Investigator should arrange an unscheduled visit if further assessment is indicated. 
23. Experimental group only: DKN-01 ADA blood will be collected on C1D1 pre-dose and on all ODD cycles (C3D1pre-dose, C5D1 pre-dose, C7D1 pre-dose, etc). If a patient 
has known positive ADA at the EOT visit, repeat testing, where feasible, will be performed in the PD Follow-up Period and/or Survival Follow-up Period until the patient is 
no longer positive. After two years on treatment, DKN-01 ADA samples will not be collected during routine visits except for at the safety follow visit unless the subject had a 
known positive ADA at the EOT visit, then they should have repeat testing, where feasible, performed in the PD Follow Up and/or Survival Follow Up period until it is no 
longer positive. 
24. Sample collection windows for the experimental group: Pre-Dose: Samples should be drawn prior to the start of the DKN-01 infusion. End of Infusion (EOI): samples 
should be collected ± 5 minutes after the end of DKN-01 infusion. 3-12 hr Post-Dose: Samples should be drawn a minimum of 3 hours after the DKN-01 infusion is 
completed. The sample can be drawn up to 12 hours after the DKN-01 infusion sample is complete. After two years on treatment,  DKK1 PK and serum samples will only be 
required at the safety follow up visit. Sample collection windows for the control group: Only Pre-Dose sample collection is required. Samples should be drawn prior to the 
start of treatment. 
25. Vital signs and ECG should be performed prior to the collection of laboratory (blood) samples at all visits if possible per sites standard process. 
26. Enrolled patients who have a history of radiation pneumonitis will receive Pulmonary Function Tests (PFT) at C1D1 and every 6 cycles ± 14 days during treatment and once 
either at the end of treatment visit (EOT) or at the Safety Follow-up Visit upon completion of therapy. 
27. Assessment of Amylase and Lipase and FT3 and FT4 will be conducted at Screening, every 3 cycles (i.e., Day 1 of Cycles 1, 4, 7, 10 etc.) during therapy and once at either 
the EOT Visit or Safety Follow-up Visit. 
28. The ophthalmic assessments including eye exam, visual acuity test and optical coherence tomography (or equivalent diagnostic test) should be performed during Screening, 
every 6 cycles ± 14 days during treatment and once at either the EOT Visit or Safety Follow-up Visit. 
29. Randomization may occur up to 3 days prior to C1D1 as long as safety labs for dosing are resulted. 
30. Sampling, handling, and processing procedures are outlined in the Laboratory Manual for plasma and serum biomarker analysis. Samples are required to be collected at 
Screening and pre-dose (prior to the start of infusion) at Day 1 of C1, C2, C3, and EOT. 
31. Sample collection windows for the experimental group only: Pre-Dose: Samples should be drawn prior to the start of the DKN-01 infusion. End of Infusion (EOI): samples 
should be collected ± 5 minutes after the end of DKN-01 infusion. 3-12 hr Post-Dose: Samples should be drawn a minimum of 3 hours after the DKN-01 infusion is 
completed. The sample can be drawn up to 12 hours after the DKN-01 infusion sample is complete. After two years on treatment, DKK1 PK and serum samples will only be 
required at the safety follow up visit. 
NOTE: All assessments should be performed prior to administration of study drugs (within -2 days) unless stated otherwise. 
 

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APPENDIX 2. CLINICAL LABORATORY ASSESSMENTS 
Serum Chemistrya 
Hematology 
Urinalysis 
Alkaline phosphatase 
Alanine aminotransferase 
Aspartate aminotransferase 
Albumin 
Total bilirubin 
Direct bilirubin 
Blood urea nitrogen or urea 
Potassium 
Sodium 
Total calciumb 
Creatinine 
Glucose 
Lactate dehydrogenase 
Total protein 
   Creatine kinasec 
Phosphorus 
Carbon dioxide 
Chloride 
Lipasef 
Amylasef 
Hematocrit 
Hemoglobin 
Platelet counts 
WBC count 
Monocytes 
Eosinophils 
Basophils 
Lymphocytes  
Neutrophils  
NLRd 
Glucose 
Protein 
Blood 
Ketones 
Coagulation 
Other Laboratory 
Assessments 
Pregnancy Testing 
Prothrombin time 
Partial thromboplastin time 
International normalized ratio 
TSH 
FT3f 
FT4f 
For women of childbearing 
potentiale 
Abbreviations: NLR = neutrophil-to-lymphocyte ratio; TSH = thyroid-stimulating hormone; WBC = white blood cell. 
a. It is acceptable to use the automated differential for complete blood count. 
b. Total calcium values will be corrected for patients with hypoproteinemia. 
c. All patients will have creatine kinase and CK-MB testing at Screening, and to be repeated at all scheduled visits during the 
first 3 treatment cycles, all predose assessments from C4 onwards, and at the End of Treatment/Safety Follow-up visit. If 
CK-MB fractionation is not available, assess troponin I and/or troponin T instead. Refer to Section 7.3.5 for additional 
information regarding clinical assessment and management of clinical laboratory abnormalities. 
d. Calculated only once at C1D1 (baseline). 
e. Serum or urine pregnancy testing is to be performed for women of childbearing potential. If a urine test is positive or cannot 
be confirmed as negative, a serum pregnancy test will be required. On C1D1, the pregnancy test may be performed within 72 
hours before the study drug dose; the results must be available and confirmed to be negative before administration of the first 
study drug dose. Pregnancy testing is to be repeated during the study any time pregnancy is suspected. Pregnant and 
breastfeeding women must not take DKN-01; hence the study Investigator may need to test to confirm that a patient is 
postmenopausal. Please see Appendix 10.  
f. For patients enrolled in the Republic of Korea only 

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APPENDIX 3. EASTERN COOPERATIVE ONCOLOGY GROUP 
(ECOG) PERFORMANCE STATUS 
Grade 
Description 
0 
Fully active, able to carry on all predisease 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 self-care but unable to carry out any work activities; up 
and about more than 50% of waking hours 
3 
Capable of only limited self-care; confined to bed or chair more than 50% of waking 
hours 
4 
Completely disabled; cannot carry on any self-care; totally confined to bed or chair 
5 
Dead 
Source: (Oken, Creech et al. 1982). Eastern Cooperative Oncology Group, Robert Comis MD, Group Chair. 

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APPENDIX 4. THE RESPONSE EVALUATION CRITERIA IN SOLID 
TUMORS (RECIST) GUIDELINES, VERSION 1.1 
Source: (Eisenhauer, Therasse et al. 2009). 
Definitions 
Response and progression will be evaluated in this trial using the international criteria proposed 
by the Response Evaluation Criteria in Solid Tumors (RECIST) Committee (v1.1). Changes in 
only the largest diameter (uni-dimensional measurement) of the tumor lesions are used in the 
RECIST criteria. 
Note: Lesions are either measurable or non-measurable using the criteria provided below. The 
term “evaluable” in reference to measurability will not be used because it does not provide 
additional meaning or accuracy. 
Measurable Disease 
Tumor lesions: Must be accurately measured in at least 1 dimension (longest diameter in the 
plane of measurement is to be recorded) with a minimum size of: 
• 10 mm by CT and magnetic resonance imaging (MRI) (no less than double the slice 
thickness and a minimum of 10 mm). Assumes a scan slice thickness no greater than 5 
mm. 
• 10 mm caliper measurement by clinical examination (when superficial) 
• 20 mm by chest Xray (if clearly defined and surrounded by aerated lung) 
Malignant lymph nodes: To be considered pathologically enlarged and measurable, a lymph 
node must be ≥15 mm in short axis when assessed by CT scan (CT scan slice thickness 
recommended to be no greater than 5 mm). At baseline and in follow-up, only the short axis will 
be measured and followed. 
Non-measurable Disease 
All other lesions (or sites of disease), including small lesions (longest diameter <10 mm or 
pathological lymph nodes with ≥10 to <15 mm short axis), are considered non-measurable 
disease. Leptomeningeal disease, ascites, pleural, or pericardial effusion, inflammatory breast 
disease, lymphangitic involvement of skin or lung, abdominal masses/abdominal organomegaly 
identified by physical examination that is not measurable by reproducible imaging techniques 
are all non-measurable. 
Bone lesions: 
• Bone scan, PET scan, or plain films are not considered adequate imaging techniques to 
measure bone lesions. However, these techniques can be used to confirm the presence 
or disappearance of bone lesions. 
• Lytic bone lesions or mixed lytic blastic lesions, with identifiable soft tissue 
components, that can be evaluated by cross sectional imaging techniques such as CT or 
MRI can be considered as measurable lesions if the soft tissue component meets the 
definition of measurability described above. 

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• Blastic bone lesions are non-measurable. 
Cystic lesions: 
• Lesions that meet the criteria for radiographically defined simple cysts should not be 
considered as malignant lesions (neither measurable nor non-measurable) since they 
are, by definition, simple cysts. 
• Cystic lesions thought to represent cystic metastases can be considered as measurable 
lesions, if they meet the definition of measurability described above. However, if non-
cystic lesions are present in the same patient, these are preferred for selection as target 
lesions. 
• Lesions with prior local treatment: 
• Tumor lesions situated in a previously irradiated area, or in an area subjected to other 
loco-regional therapy, are usually not considered measurable unless there has been 
demonstrated progression in the lesion. Trial protocols should detail the conditions 
under which such lesions would be considered measurable. 
Target Lesions 
All measurable lesions up to a maximum of 2 lesions per organ and 5 lesions in total, should be 
identified as target lesions and recorded and measured at baseline. Target lesions should be 
selected on the basis of their size (lesions with the longest diameter), be representative of all 
involved organs, but in addition should be those that lend themselves to reproducible repeated 
measurements. 
Lymph nodes merit special mention since they are normal anatomical structures which may be 
visible by imaging even if not involved by tumor. Pathological nodes which are defined as 
measurable and may be identified as target lesions must meet the criterion of a short axis of 
≥15 mm by CT scan. Only the short axis of these nodes will contribute to the baseline sum. The 
short axis of the node is the diameter normally used by radiologists to judge if a node is 
involved by solid tumor. Nodal size is normally reported as 2 dimensions in the plane in which 
the image is obtained (for CT scan, this is almost always the axial plane; for MRI the plane of 
acquisition may be axial, sagittal, or coronal). The smaller of these measures is the short axis. 
For example, an abdominal node which is reported as being 20 mm by 30 mm has a short axis 
of 20 mm and qualifies as a malignant, measurable node. In this example, 20 mm should be 
recorded as the node measurement. All other pathological nodes (those with short axis ≥10 mm 
but <15 mm) should be considered nontarget lesions. Nodes that have a short axis <10 mm are 
considered nonpathological and should not be recorded or followed. 
A sum of the diameters (longest for non-nodal lesions, short axis for nodal lesions) for all target 
lesions will be calculated and reported as the baseline sum diameters. If lymph nodes are to be 
included in the sum, then as noted above, only the short axis is added into the sum. The baseline 
sum diameters will be used as reference to further characterize any objective tumor regression in 
the measurable dimension of the disease. 

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Non-target Lesions 
All other lesions (or sites of disease) including pathological lymph nodes should be identified as 
nontarget lesions and should also be recorded at baseline. Measurements are not required, and 
these lesions should be followed as “present,” “absent,” or in rare cases “unequivocal 
progression” (more details to follow). In addition, it is possible to record multiple nontarget 
lesions involving the same organ as a single item on the case record form (e.g., “multiple 
enlarged pelvic lymph nodes” or “multiple liver metastases”). 
Guidelines for Evaluation of Measurable Disease 
All measurements should be recorded in metric notation, using calipers if clinically assessed. 
All baseline evaluations should be performed as close as possible to the treatment start and 
never more than 4 weeks before the beginning of the treatment. 
The same method of assessment and the same technique should be used to characterize each 
identified and reported lesion at baseline and during follow-up. Imaging-based evaluation 
should always be done rather than clinical examination unless the lesion(s) being followed 
cannot be imaged but are assessable by clinical examination. 
• Clinical lesions: Clinical lesions will only be considered measurable when they are 
superficial and ≥10 mm diameter as assessed using calipers (e.g., skin nodules). For the 
case of skin lesions, documentation by color photography including a ruler to estimate 
the size of the lesion is suggested. As noted above, when lesions can be evaluated by 
both clinical examination and imaging, imaging evaluation should be undertaken since 
it is more objective and may also be reviewed at the end of the trial. 
• Chest Xray: Chest CT is preferred over chest Xray, particularly when progression is an 
important endpoint, since CT is more sensitive than Xray, particularly in identifying 
new lesions. However, lesions on chest Xray may be considered measurable if they are 
clearly defined and surrounded by aerated lung. 
• CT, MRI: CT is the best currently available and reproducible method to measure 
lesions selected for response assessment. This guideline has defined measurability of 
lesions on CT scan based on the assumption that CT slice thickness is 5 mm or less. 
When CT scans have slice thickness greater than 5 mm, the minimum size for a 
measurable lesion should be twice the slice thickness. MRI is also acceptable in certain 
situations (e.g., for body scans). 
• Ultrasound: Ultrasound is not useful in assessment of lesion size and should not be 
used as a method of measurement. Ultrasound examinations cannot be reproduced in 
their entirety for independent review at a later date, and because they are operator 
dependent, it cannot be guaranteed that the same technique and measurements will be 
taken from one assessment to the next. If new lesions are identified by ultrasound in the 
course of the study, confirmation by CT or MRI is advised. If there is concern about 
radiation exposure at CT, MRI may be used instead of CT in selected instances. 
• Endoscopy, laparoscopy: The utilization of these techniques for objective tumor 
evaluation is not advised. However, they can be useful to confirm complete 
pathological response when biopsies are obtained or to determine relapse in trials 

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where recurrence following complete response (CR) or surgical resection is an 
endpoint. 
• Tumor markers: Tumor markers alone cannot be used to assess objective tumor 
response. If markers are initially above the upper normal limit, however, they must 
normalize for a patient to be considered in CR. Because tumor markers are disease 
specific, instructions for their measurement should be incorporated into protocols on a 
disease specific basis. Specific guidelines for both CA125 response (in recurrent 
ovarian cancer) and prostate-specific antigen response (in recurrent prostate cancer), 
have been published. In addition, the Gynecologic Cancer Intergroup has developed 
CA125 progression criteria which are to be integrated with objective tumor assessment 
for use in first-line trials in ovarian cancer. 
• Cytology, histology: These techniques can be used to differentiate between partial 
response (PR) and CR in rare cases if required by protocol (for example, residual 
lesions in tumor types such as germ cell tumors, where known residual benign tumors 
can remain). When effusions are known to be a potential adverse effect of treatment 
(e.g., with certain taxane compounds or angiogenesis inhibitors), the cytological 
confirmation of the neoplastic origin of any effusion that appears or worsens during 
treatment can be considered if the measurable tumor has met criteria for response or 
stable disease in order to differentiate between response (or stable disease) and 
progressive disease. 
Response Criteria 
Evaluation of Target Lesions 
• Complete Response (CR): Disappearance of all target lesions. Any pathological 
lymph nodes (whether target or nontarget) must have reduction in short axis to 
<10 mm. 
• Partial Response (PR): At least a 30% decrease in the sum of diameters of target 
lesions, taking as reference the baseline sum diameters 
• Progressive Disease (PD): At least a 20% increase in the sum of diameters of target 
lesions, taking as reference the smallest sum on study (this includes the baseline sum 
if that is the smallest on study). In addition to the relative increase of 20%, the sum 
must also demonstrate an absolute increase of at least 5 mm. (Note: The appearance 
of one or more new lesions is also considered progression). 
• Stable Disease (SD): Neither sufficient shrinkage to qualify for PR nor sufficient 
increase to qualify for PD, taking as reference the smallest sum diameters while on 
study 
• Lymph nodes: Lymph nodes identified as target lesions should always have the 
actual short axis measurement recorded (measured in the same anatomical plane as 
the baseline examination), even if the nodes regress to below 10 mm on study. This 
means that when lymph nodes are included as target lesions, the “sum” of lesions 
may not be zero even if CR criteria are met, since a normal lymph node is defined as 
having a short axis of <10 mm. Case report form may be designed to have target 

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nodal lesions recorded in a separate section where, in order to qualify for CR, each 
node must achieve a short axis <10 mm. For PR, SD and PD, the actual short axis 
measurement of the nodes is to be included in the sum of target lesions. 
• Target lesions that become “too small to measure.” While on study, all lesions (nodal 
and non-nodal) recorded at baseline should have their actual measurements recorded 
at each subsequent evaluation, even when very small (e.g., 2 mm). However, 
sometimes lesions or lymph nodes which are recorded as target lesions at baseline 
become so faint on CT scan that the radiologist may not feel comfortable assigning 
an exact measure and may report them as being “too small to measure.” 
When this occurs, it is important that a value be recorded on the electronic case 
report form (eCRF). If it is the opinion of the radiologist that the lesion has likely 
disappeared, the measurement should be recorded as 0 mm. If the lesion is believed 
to be present and is faintly seen but too small to measure, a default value of 5 mm 
should be assigned. (Note: It is less likely that this rule will be used for lymph nodes 
since they usually have a definable size when normal and are frequently surrounded 
by fat, such as in the retroperitoneum; however, if a lymph node is believed to be 
present and is faintly seen but too small to measure, a default value of 5 mm should 
be assigned in this circumstance as well). This default value is derived from the 
5 mm CT slice thickness (but should not be changed with varying CT slice 
thickness). The measurement of these lesions is potentially nonreproducible; 
therefore, providing this default value will prevent false responses or progressions 
based upon measurement error. To reiterate, however, if the radiologist is able to 
provide an actual measure, that measurement should be recorded, even if it is below 
5 mm. 
• Lesions that split or coalesce on treatment: When nonnodal lesions “fragment,” the 
longest diameters of the fragmented portions should be added together to calculate 
the target lesion sum. Similarly, as lesions coalesce, a plane between them may be 
maintained that would aid in obtaining maximal diameter measurements of each 
individual lesion. If the lesions have truly coalesced such that they are no longer 
separable, the vector of the longest diameter in this instance should be the maximal 
longest diameter for the “coalesced lesion.” 
Evaluation of Non-target Lesions 
While some non-target lesions may actually be measurable, they need not be measured and 
instead should be assessed only qualitatively at the time points specified in the protocol. 
• CR: Disappearance of all nontarget lesions and normalization of tumor marker level. 
All lymph nodes must be nonpathological in size (<10 mm short axis). 
• NonCR/NonPD: Persistence of one or more nontarget lesion(s) and/or maintenance 
of tumor marker level above the normal limits 
• PD: Unequivocal progression (as detailed below) of existing nontarget lesions. 
(Note: The appearance of one or more new lesions is also considered progression.) 
• When the patient also has measurable disease: In this setting, to achieve 
“unequivocal progression” on the basis of the nontarget disease, there must be an 

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overall level of substantial worsening in nontarget disease such that, even in presence 
of SD or PR in target disease, the overall tumor burden has increased sufficiently to 
merit discontinuation of therapy. A modest “increase” in the size of one or more 
nontarget lesions is usually not sufficient to qualify for unequivocal progression 
status. The designation of overall progression solely on the basis of change in 
nontarget disease in the face of SD or PR of target disease will therefore be 
extremely rare. 
• When the patient has only non-measurable disease: This circumstance arises in some 
phase 3 trials when it is not a criterion of trial entry to have measurable disease. The 
same general concept applies here as noted above; however, in this instance there is 
no measurable disease assessment to factor into the interpretation of an increase in 
non-measurable disease burden. Because worsening in non-target disease cannot be 
easily quantified (by definition: if all lesions are truly non-measurable) a useful test 
that can be applied when assessing patients for unequivocal progression is to 
consider if the increase in overall disease burden based on the change in non-
measurable disease is comparable in magnitude to the increase that would be 
required to declare PD for measurable disease: i.e., an increase in tumor burden 
representing an additional 73% increase in “volume” (which is equivalent to a 20% 
increase diameter in a measurable lesion). 
• Examples include an increase in a pleural effusion from “trace” to “large,” an 
increase in lymphangitic disease from localized to wide-spread, or may be described 
in protocols as “sufficient to require a change in therapy.” If “unequivocal 
progression” is seen, the patient should be considered to have had overall PD at that 
point. While it would be ideal to have objective criteria to apply to non-measurable 
disease, the very nature of that disease makes it impossible to do so; therefore, the 
increase must be substantial. 
New Lesions 
The appearance of new malignant lesions denotes disease progression; therefore, some 
comments on detection of new lesions are important. There are no specific criteria for the 
identification of new radiographic lesions; however, the finding of a new lesion should be 
unequivocal: i.e., not attributable to differences in scanning technique, change in imaging 
modality or findings thought to represent something other than tumor (for example, some “new” 
bone lesions may be simply healing or flare of preexisting lesions). This is particularly 
important when the patient’s baseline lesions show partial or complete response. For example, 
necrosis of a liver lesion may be reported on a CT scan report as a “new” cystic lesion, which it 
is not. 
A lesion identified on a follow-up trial in an anatomical location that was not scanned at 
baseline is considered a new lesion and will indicate disease progression. An example of this is 
the patient who has visceral disease at baseline and while on study has a CT or MRI brain scan 
ordered that reveals metastases. The patient’s brain metastases are considered to be evidence of 
PD even if he/she did not have brain imaging at baseline. 

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If a new lesion is equivocal, for example because of its small size, continued therapy and 
follow-up evaluation will clarify if it represents truly new disease. If repeat scans confirm there 
is definitely a new lesion, then progression should be declared using the date of the initial scan. 
While fluorodeoxyglucose (FDG)-PET response assessments need additional study, it is 
sometimes reasonable to incorporate the use of FDG-PET scanning to complement CT scanning 
in assessment of progression (particularly possible “new” disease). New lesions on the basis of 
FDG-PET imaging can be identified according to the following algorithm: 
• Negative FDGPET at baseline, with a positive FDGPET at followup, is a sign of PD 
based on a new lesion. 
• No FDGPET at baseline and a positive FDGPET at followup: If the positive 
FDGPET at followup corresponds to a new site of disease confirmed by CT, this is 
PD. If the positive FDGPET at followup is not confirmed as a new site of disease on 
CT, additional followup CT scans are needed to determine if there is truly 
progression occurring at that site (if so, the date of PD will be the date of the initial 
abnormal FDGPET scan). If the positive FDGPET at followup corresponds to a 
preexisting site of disease on CT that is not progressing on the basis of the anatomic 
images, this is not PD. 
• Timepoint Response 
• It is assumed that at each protocol specified time point, a response assessment 
occurs. The following table provides a summary of the overall response status 
calculation at each time point for patients who have measurable disease at baseline: 
Target Lesions 
Nontarget Lesions 
New Lesions 
Overall Response 
CR 
CR 
No 
CR 
CR 
Non-CR/non-PD 
No 
PR 
CR 
Not evaluated 
No 
PR 
PR 
Non-PD or not all evaluated 
No 
PR 
SD 
Non-PD or not all evaluated 
No 
SD 
Not all evaluated 
Non-PD 
No 
NE 
PD 
Any 
Yes or No 
PD 
Any 
PD 
Yes or No 
PD 
Any 
Any 
Yes 
PD 
Abbreviations: CR = complete response; NE = not evaluable; PD = progressive disease;  
PR = partial response; SD = stable disease. 
When patients have nonmeasurable (therefore nontarget) disease only, the following table is to 
be used: 
Nontarget Lesions 
New Lesions 
Overall Response 
CR 
No 
CR 
Non-CR/non-PD 
No 
SD (Non-CR/non-PD) 
Not all evaluated 
No 
NE 

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Nontarget Lesions 
New Lesions 
Overall Response 
Unequivocal PD 
Yes or No 
PD 
Any 
Yes 
PD 
Abbreviations: CR = complete response; NE = not evaluable; PD = progressive disease;  
SD = stable disease. 
Evaluation of Best Overall Response 
The best overall response is the best response recorded from the start of the study drug treatment 
until the end of treatment taking into account any requirement for confirmation. On occasion a 
response may not be documented until after the end of therapy so protocols should be clear if 
post-treatment assessments are to be considered in determination of best overall response. 
Protocols must specify how any new therapy introduced before progression will affect best 
response designation. The patient’s best overall response assignment will depend on the findings 
of both target and nontarget disease and will also take into consideration the appearance of new 
lesions. Furthermore, depending on the nature of the trial and the protocol requirements, it may 
also require confirmatory measurement. Specifically, in nonrandomized trials where response is 
the primary endpoint, confirmation of PR or CR is needed to deem either one the “best overall 
response.” 
The best overall response is determined once all the data for the patient is known. 
Best response determination in trials where confirmation of complete or partial response IS 
NOT required: Best response in these trials is defined as the best response across all time points 
(for example, a patient who has SD at first assessment, PR at second assessment, and PD on last 
assessment has a best overall response of PR). When SD is believed to be best response, it must 
also meet the protocol specified minimum time from baseline. If the minimum time is not met 
when SD is otherwise the best time point response, the patient’s best response depends on the 
subsequent assessments. For example, a patient who has SD at first assessment, PD at second 
and does not meet minimum duration for SD, will have a best response of PD. The same patient 
lost to follow-up after the first SD assessment would be considered inevaluable. 
Best response determination in trials where confirmation of complete or partial response IS 
required: Complete or partial responses may be claimed only if the criteria for each are met at a 
subsequent time point as specified in the protocol (generally 4 weeks later). 
When nodal disease is included in the sum of target lesions and the nodes decrease to “normal” 
size (<10 mm), they may still have a measurement reported on scans. This measurement should 
be recorded even though the nodes are normal in order not to overstate progression should it be 
based on increase in size of the nodes. As noted earlier, this means that patients with CR may 
not have a total sum of “zero.” 
In trials where confirmation of response is required, repeated "NE" (not evaluable) time point 
assessments may complicate best response determination. The analysis plan for the trial must 
address how missing data/assessments will be addressed in determination of response and 
progression. For example, in most trials it is reasonable to consider a patient with time point 
responses of PR-NE-PR as a confirmed response. 
Patients with a global deterioration of health status requiring discontinuation of treatment 
without objective evidence of disease progression at that time should be reported as 

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“symptomatic deterioration”. Every effort should be made to document objective progression 
even after discontinuation of treatment. Symptomatic deterioration is not a descriptor of an 
objective response: it is a reason for stopping trial therapy. 
Conditions that define “early progression, early death, and inevaluability” are trial specific and 
should be clearly described in each protocol (depending on treatment duration, treatment 
periodicity). 
In some circumstances it may be difficult to distinguish residual disease from normal tissue. 
When the evaluation of CR depends upon this determination, it is recommended that the 
residual lesion be investigated (fine needle aspirate/biopsy) before assigning a status of CR. 
FDG-PET may be used to upgrade a response to a CR in a manner similar to a biopsy in cases 
where a residual radiographic abnormality is thought to represent fibrosis or scarring. The use of 
FDG-PET in this circumstance should be prospectively described in the protocol and supported 
by disease specific medical literature for the indication. However, it must be acknowledged that 
both approaches may lead to false positive CR due to limitations of FDG-PET and biopsy 
resolution/ sensitivity. 
For equivocal findings of progression (e.g., very small and uncertain new lesions; cystic 
changes, or necrosis in existing lesions), treatment may continue until the next scheduled 
assessment. If progression is confirmed at the next scheduled assessment, the date of 
progression should be the earlier date when progression was suspected. 
Confirmation of Measurement/Duration of Response 
Confirmation 
In nonrandomized trials where response is the primary endpoint, confirmation of PR and CR is 
required to ensure responses identified are not the result of measurement error. This will also 
permit appropriate interpretation of results in the context of historical data where response has 
traditionally required confirmation in such trials. However, in all other circumstances, i.e., in 
randomized trials (phase 2 or 3) or trials where stable disease or progression are the primary 
endpoints, confirmation of response is not required since it will not add value to the 
interpretation of trial results. However, elimination of the requirement for response confirmation 
may increase the importance of central review to protect against bias, in particular in trials 
which are not blinded. 
In the case of SD, measurements must have met the SD criteria at least once after trial entry at a 
minimum interval (in general not less than 6 weeks). 
Duration of Overall Response 
The duration of overall response is measured from the time measurement criteria are first met 
for CR/PR (whichever is first recorded) until the first date that recurrent or progressive disease 
is objectively documented (taking as reference for progressive disease the smallest 
measurements recorded on study). 
The duration of overall CR is measured from the time measurement criteria are first met for CR 
until the first date that recurrent disease is objectively documented. 

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Duration of Stable Disease 
Stable disease is measured from the start of the treatment (in randomized trials, from date of 
randomization) until the criteria for progression are met, taking as reference the smallest sum on 
study (if the baseline sum is the smallest, this is the reference for calculation of PD). 
The clinical relevance of the duration of stable disease varies in different studies and diseases. If 
the proportion of patients achieving stable disease for a minimum period of time is an endpoint 
of importance in a particular trial, the protocol should specify the minimal time interval required 
between 2 measurements for determination of stable disease. 
Note: The duration of response and stable disease as well as the progression-free survival are 
influenced by the frequency of follow-up after baseline evaluation. It is not in the scope of this 
guideline to define a standard follow-up frequency. The frequency should take into account 
many parameters including disease types and stages, treatment periodicity, and standard 
practice. However, these limitations of the precision of the measured endpoint should be taken 
into account if comparisons between trials are to be made. 

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APPENDIX 5. PREEXISTING IMMUNE DEFICIENCIES OR 
AUTOIMMUNE DISEASES 
Prospective patients should be carefully questioned to determine whether they have any history 
of an acquired or congenital immune deficiency or autoimmune disease. 
Please contact the Medical Monitor regarding any uncertainty about immune 
deficiency/autoimmune disease exclusions. 
Acute disseminated encephalomyelitis 
Addison disease 
Ankylosing spondylitis 
Antiphospholipid antibody syndrome 
Aplastic anemia 
Autoimmune hemolytic anemia 
Autoimmune hepatitis 
Autoimmune hypoparathyroidism 
Autoimmune hypophysitis 
Autoimmune myocarditis 
Autoimmune oophoritis 
Autoimmune orchitis 
Autoimmune thrombocytopenic purpura 
Behcet disease 
Bullous pemphigoid 
Chronic inflammatory demyelinating polyneuropathy 
Chung-Strauss syndrome 
Crohn disease 
Dermatomyositis 
Dysautonomia 
Epidermolysis bullosa acquisita 
Gestational pemphigoid 
Giant cell arteritis 
Goodpasture syndrome 
Granulomatosis with polyangiitis 
Graves disease 
Guillain-Barré syndrome 
Hashimoto disease 
Immunoglobulin A (IgA) neuropathy 
Inflammatory bowel disease 
Interstitial cystitis 
Kawasaki disease 
Lambert-Eaton myasthenic syndrome 
Lupus erythematosus 
Lyme disease (chronic) 
Mooren ulcer 
Morphea 
Multiple sclerosis 
Myasthenia gravis 
Neuromyotonia 
Opsoclonus myoclonus syndrome 
Optic neuritis 
Ord thyroiditis 
Pemphigus 
Pernicious anemia 
Polyarteritis nodosa 
Polyarthritis 
Polyglandular autoimmune syndrome 
Primary biliary cirrhosis 
Psoriasis 
Reiter syndrome 
Rheumatoid arthritis 
Sarcoidosis  
Sjögren syndrome 
Stiff person syndrome 
Takayasu arteritis 
Ulcerative colitis 
Vogt-Kovangai-Harada disease 
 

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APPENDIX 6. NEW YORK HEART ASSOCIATION FUNCTIONAL 
CLASSIFICATION 
Class 
Symptoms 
I 
No limitation of physical activity. Ordinary physical activity does not cause undue 
fatigue, palpitation, dyspnea (shortness of breath). 
II 
Slight limitation of physical activity. Comfortable at rest, but ordinary physical activity 
results in fatigue, palpitation, dyspnea (shortness of breath). 
III 
Marked limitation of physical activity. Comfortable at rest, but less than ordinary 
activity causes fatigue, palpitation, or dyspnea. 
IV 
Unable to carry on any physical activity without discomfort. Symptoms of heart failure 
at rest. If any physical activity is undertaken, discomfort increases. 
Adapted from (Dolgin, Association et al. 1994). 
Original source: Criteria Committee, New York Heart Association, Inc. Diseases of the Heart and Blood Vessels. 
Nomenclature and Criteria for diagnosis, 6th edition Boston, Little, Brown and Co. 1964, p 114. 

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APPENDIX 7. MANAGEMENT OF POSSIBLE DKN-01-ASSOCIATED 
ADVERSE EFFECTS 
System Monitoring 
Severity 
Management 
Follow-up 
Gastrointestinal 
Any changes in 
normal bowel habits 
or changes from BL: 
• Diarrhea 
• Abdominal pain 
• Blood or mucus in 
stool with or 
without fever 
• Peritoneal signs 
consistent with 
bowel perforation 
• Ileus 
 
Moderate: 
• 4 to 6 stools/day over 
baseline 
• Abdominal pain 
• Blood or mucus in stool 
• Withhold DKN-01 
• Administer 
antidiarrheal 
treatment while 
etiology is 
investigated. 
Symptoms Resolve to ≤Grade 
1 or baseline (Section 5.2.3): 
• Resume DKN-01 as per 
Table 10 or Table 11 as 
applicable if symptoms 
have improved to mild 
severity or resolution. 
Severe or life-threatening: 
• 7 stools/day over baseline 
• Peritoneal signs consistent 
with bowel perforation 
• Ileus 
• Fever 
• Permanently 
discontinue DKN-01 
• Rule out bowel 
perforation 
• Consider endoscopic 
evaluation 
 
 
Liver 
 
 
 
Elevations in liver 
function tests: 
• AST >2.5 × ULN 
• ALT >2.5 × ULN 
• Total 
bilirubin >1.5 × 
ULN 
 
Moderate: 
• AST or ALT >2.5 to <5.0 × 
ULN and/or 
• Total bilirubin >1.5 to <3.0 
× ULN 
• Withhold DKN-01 
• Rule out infectious 
or malignant causes 
• Increase frequency 
of liver function test 
monitoring until 
resolution 
Symptoms Resolve to ≤Grade 
1 or baseline (Section 5.2.3): 
• Resume DKN-01 as per 
Table 10 or Table 11 as 
applicable if liver function 
tests are <2.5 × ULN or 
return to BL and bilirubin is 
<1.5 × ULN or returns to 
BL. 
Symptoms Ongoing: 
• If AST or ALT elevation 
continues to be >5 × ULN 
OR total bilirubin >3 × 
ULN, see below. 
Severe or life-threatening 
• AST or ALT >5.0 × ULN 
and/or 
• Total bilirubin >3.0 × ULN 
• Permanently 
discontinue DKN-01 
• Rule out infectious 
or malignant causes 
• Increase frequency 
of liver function test 
monitoring until 
resolution 
 

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System Monitoring 
Severity 
Management 
Follow-up 
Skin 
• Pruritus 
• Rash 
 
Moderate 
• Non-localized rash (diffuse, 
<50% of skin surface 
• Withhold DKN-01 
• Administer topical 
corticosteroids if 
there is no 
improvement of 
symptoms within 1 
week. 
Symptoms Resolve to ≤Grade 
1 or baseline (Section 5.2.3): 
• Resume DKN-01 as per 
Table 10 or Table 11 as 
applicable if dermatitis 
resolves or improves to 
mild (localized) symptoms. 
Symptoms Ongoing: 
• If symptoms worsen, see 
below. 
Severe or life-threatening 
• Stevens-Johnson syndrome, 
toxic epidermal necrolysis, 
or rash complicated by full 
thickness dermal 
ulceration, or necrotic, 
bullous or hemorrhagic 
manifestations 
• Permanently 
discontinue DKN-01 
• Administer systemic 
corticosteroid 
therapy 
 
Neurologic 
Monitor for 
symptoms of motor 
or sensory 
neuropathy 
• Unilateral or 
bilateral weakness 
• Sensory alterations 
• Paresthesia 
. 
Moderate 
• Moderate symptoms, 
clinically detectable with 
no impact on ADLs 
• Withhold DKN-01 
• Introduce 
appropriate medical 
intervention 
Symptoms Resolve to ≤Grade 
1 or baseline (Section 5.2.3): 
• Resume DKN-01 as per 
Table 10 or Table 11 as 
applicable when symptoms 
resolve or return to BL 
Symptoms Ongoing: 
• If symptoms worsen, see 
below 
Severe or life-threatening 
• Severe symptoms (impact 
on ADLs) or life-
threatening 
• Permanently 
discontinue DKN-01 
• Institute appropriate 
medical intervention 
 
Endocrine 
• Fatigue 
• Headache 
• Mental status 
changes 
• Abdominal pain 
• Unusual bowel 
habits 
• Hypotension 
• Abnormal thyroid 
function tests 
and/or serum 
chemistries 
 
Moderate to life-
threatening 
• Document signs and/or 
symptoms of dysfunction 
• Endocrinopathies requiring 
hormone replacement or 
medical intervention 
• AEs requiring 
hospitalization, urgent 
medical intervention or 
interfering with ADLs 
• Withhold DKN-01 
• Evaluate endocrine 
function 
• Consider 
radiographic 
pituitary gland 
imaging 
• Continue to assess as 
indicated 
• Initiate appropriate 
hormone-
replacement therapy 
Symptoms Resolve to ≤Grade 
1 or baseline (Section 5.2.3): 
• Resume DKN-01 as per 
Table 10 or Table 11 as 
applicable when: 
• Patient is stable on 
hormone-replacement 
therapy (as indicated) 
Symptoms Ongoing: 
• Permanently discontinue 
DKN-01  
Abbreviations: ADL = activities of daily living; ALT = alanine aminotransferase; AST = aspartate aminotransferase; 
BL = baseline; ULN = upper limit of normal. 

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APPENDIX 8. IMMUNE-RELATED ADVERSE EVENT EVALUATION 
AND MANAGEMENT 
The recommendations below for the diagnosis and management of any irAE are intended as a 
guidance. This document should be used in conjunction with expert clinical judgement (by 
specialist physicians experienced in the treatment of cancer using immunological agents), and 
individual institutional guidelines or policies. 
Criteria used to diagnose irAEs include blood tests, diagnostic imaging, histopathology, and 
microbiology assessments to exclude alternative causes such as infection, disease progression, 
and adverse effects of concomitant drugs. In addition to the results of these tests, the following 
factors should be considered when making an irAE diagnosis: 
• What was the temporal relationship between initiation of tislelizumab and the AE? 
• How did the patient respond to withdrawal of tislelizumab? 
• Did the event recur when tislelizumab was reintroduced? 
• Was there a clinical response to corticosteroids? 
• Is the event an autoimmune endocrinopathy? 
• Is disease progression or an alternative diagnosis a more likely explanation? 
When alternative explanations to autoimmune toxicity have been excluded, the irAE field 
associated with the AE in the eCRF should be checked. If further diagnostic evaluations change 
the assessment, the eCRF should be updated accordingly. 
Recommended Diagnostic Tests in the Management of Possible Immune-related Adverse Events 
Immune-related Toxicity 
Diagnostic Evaluation Guideline 
Thyroid Disorders 
Scheduled and repeated thyroid function tests (TSH and T4). 
Hypophysitis 
Check visual fields and consider pituitary endocrine axis blood profile. Perform 
pituitary and whole brain MRI in patients with headache, visual disturbance, 
unexplained fatigue, asthenia, weight loss, and unexplained constitutional 
symptoms. 
Consider consultation with an endocrinologist if an abnormality is detected. 
Pneumonitis 
All patients presenting with new or worsened pulmonary symptoms or signs, such 
as an upper respiratory infection, new cough, shortness of breath, or hypoxia 
should be assessed by high-resolution CT. Consider pulmonary function test 
including DLCO. 
Radiographic appearance is often nonspecific. Depending on the location of the 
abnormality, bronchoscopy and bronchoalveolar lavage or lung biopsy may be 
considered. Consult with a respiratory medicine physician for cases of uncertain 
cause.  
Neurological Toxicity 
Perform a comprehensive neurological examination and brain MRI for all CNS 
symptoms; review alcohol history and other medications. Conduct a diabetic 
screen and assess blood B12/folate, HIV status, TFTs, and consider autoimmune 
serology. Consider the need for brain/spine MRI/MRA and nerve conduction study 
for peripheral neuropathy. Consult with a neurologist if there are abnormal 
findings. 

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Recommended Diagnostic Tests in the Management of Possible Immune-related Adverse Events 
Immune-related Toxicity 
Diagnostic Evaluation Guideline 
Colitis 
Review dietary intake and exclude steatorrhea. Consider comprehensive testing, 
including the following: FBC, UEC, LFTs, CRP, TFTs, stool microscopy and 
culture, viral PCR, Clostridium difficile toxin, and cryptosporidia (drug-resistant 
organism). 
In case of abdominal discomfort, consider imaging, e.g., X-ray, CT scan. If a 
patient experiences bleeding, pain, or distension, consider colonoscopy with 
biopsy and surgical intervention as appropriate. 
Eye Disorders 
If a patient experiences acute, new onset, or worsening of eye inflammation; 
blurred vision; or other visual disturbances, refer the patient urgently to an 
ophthalmologist for evaluation and management. 
Hepatitis 
Check ALT/AST/total bilirubin, INR/albumin; the frequency will depend on 
severity of the AE (e.g., daily if Grade 3 to 4; every 2 to 3 days if Grade 2, until 
recovering). Review medications (e.g., statins, antibiotics) and alcohol history. 
Perform liver screen including Hepatitis A/B/C serology, Hepatitis E PCR and 
assess anti-ANA/SMA/LKM/SLA/LP/LCI, iron studies. Consider imaging (e.g., 
ultrasound scan for metastases or thromboembolism). Consult with a hepatologist 
and consider liver biopsy. 
Renal toxicity 
Review hydration status and medication history. Test and culture urine. Consider 
renal ultrasound scan, protein assessment (dipstick/24-hour urine collection), or 
phase-contrast microscopy. Refer to a nephrologist for further management 
assistance. 
Dermatology 
Consider other causes by conducting a physical examination. Consider 
dermatology referral for skin biopsy. 
Joint or muscle 
inflammation 
Conduct musculoskeletal history and perform complete musculoskeletal 
examination. Consider joint X-ray and other imaging as required to exclude 
metastatic disease. Perform autoimmune serology and refer to rheumatology for 
further management assistance. 
For suspected myositis/rhabdomyolysis/myasthenia include: CK, ESR, CRP, 
troponin, and consider a muscle biopsy. 
Myocarditis 
Perform ECG, echocardiogram, CK/CK-MB, troponin (I and/or T), and refer to a 
cardiologist. 
Abbreviations: AE = adverse event; ALT = alanine aminotransferase; ANA = antinuclear antibody; AST = aspartate 
aminotransferase; CK = creatine kinase; CK-MB = creatine kinase cardiac isoenzyme; CNS = central nervous 
system; CRP = C-reactive protein; CT = computed tomography; DLCO = diffusing capacity for carbon monoxide; 
ECG = electrocardiogram; ESR = erythrocyte sedimentation rate; FBC = full blood count; HIV = human 
immunodeficiency virus; INR = international normalized ratio; LCI = liver cytosolic antigen; LFT = liver function 
test; LKM = liver kidney microsomal antibody; LP = liver pancreas antigen; MRA = magnetic resonance 
angiogram; MRI = magnetic resonance imaging; PCR = polymerase chain reaction; SLA = soluble liver antigen; 
SMA = smooth muscle antibody; T4 = thyroxine; TFT = thyroid function tests; TSH = thyroid-stimulating hormone; 
UEC = urea electrolytes and creatinine. 
 
Treatment of Immune-Related Adverse Events 
• Immune-related AEs can escalate quickly. Study treatment interruption, close monitoring, 
timely diagnostic work-up, and treatment intervention as appropriate is required. 

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• Immune-related AEs should improve promptly after introduction of immunosuppressive 
therapy. If this does not occur, review the diagnosis, seek further specialist advice, and 
contact the study Medical Monitor. 
• For some Grade 3 toxicities that resolve quickly, rechallenge with study drug may be 
considered if there is evidence of a clinical response to study treatment, after consultation 
with the study Medical Monitor. 
• Steroid dosages in the table below are for oral or intravenous (methyl)prednisolone. 
Equivalent dosages of other corticosteroids can be substituted. For steroid-refractory 
irAEs, consider use of steroid-sparing agents (e.g., mycophenolate mofetil [MMF]). 
• Consider prophylactic antibiotics for opportunistic infections if the patient is receiving 
longterm immunosuppressive therapy. 
 
Autoimmune 
Toxicity 
Grade 
Treatment Guidelines (Subject 
to Clinical Judgement) 
Study Drug 
Management 
Thyroid 
Disorders 
1-2 
Asymptomatic TFT abnormality 
or mild symptoms 
Replace thyroxine if hypothyroid, 
until TSH/T4 levels return to 
normal range. 
Thyrotoxic patients should be 
referred to an endocrinologist. In 
cases with systemic symptoms: 
withhold study treatment, treat 
with a beta blocker, and consider 
oral prednisolone 0.5 mg/kg/day 
for thyroid pain. 
Taper corticosteroids over 2-4 
weeks. Monitor thyroid function 
regarding the need for hormone 
replacement. 
Continue study 
treatment or 
withhold 
treatment in cases 
with systemic 
symptoms. 
3-4 
Severe symptoms, hospitalization 
required 
Refer patient to an endocrinologist. 
If hypothyroid, replace with 
thyroxine 0.5-1.6 µg/kg/day (for 
the elderly or those with 
comorbidities, the suggested 
starting dose is 0.5 µg/kg/day). 
Add oral prednisolone 
0.5 mg/kg/day for thyroid pain. 
Thyrotoxic patients require 
treatment with a beta blocker and 
may require carbimazole until 
thyroiditis resolves. 
Hold study 
treatment; resume 
when 
resolved/improved 
to Grade 0-1.  
 

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Autoimmune 
Toxicity 
Grade 
Treatment Guidelines (Subject 
to Clinical Judgement) 
Study Drug 
Management 
Hypophysitis 
1-2 
Mild-moderate symptoms 
Refer patient to an endocrinologist 
for hormone replacement. 
Add oral prednisolone 
0.5-1 mg/kg/day for patients with 
pituitary inflammation. Taper 
corticosteroids over at least 
1 month. 
If there is no improvement in 
48 hours, treat as Grade 3-4. 
Continue study 
treatment. 
3-4 
Severe or life-threatening 
symptoms 
Refer patient to an endocrinologist 
for assessment and treatment. 
Initiate pulse intravenous 
methylprednisolone 1 mg/kg for 
patients with headache/visual 
disturbance due to pituitary 
inflammation. Convert to oral 
prednisolone and taper over at 
least 1 month. 
Maintain hormone replacement 
according to endocrinologist’s 
advice. 
Hold study 
treatment for 
patients with 
headache/visual 
disturbance due to 
pituitary 
inflammation until 
resolved/improved 
to ≤Grade 2. 
Discontinuation is 
usually not 
necessary.  
 
Pneumonitis 
1 
Radiographic changes only 
Monitor symptoms every 2-3 days.  
If appearance worsens, treat as 
Grade 2. 
Consider holding 
study treatment 
until appearance 
improves and 
cause is 
determined. 
2 
Symptomatic: exertional 
breathlessness 
Commence antibiotics if infection 
suspected. Add oral prednisolone 
1 mg/kg/day if 
symptoms/appearance persist for 
48 hours or worsen. 
Consider Pneumocystis infection 
prophylaxis. Taper corticosteroids 
over at least 6 weeks. 
Consider prophylaxis for adverse 
steroid effects: e.g., blood glucose 
monitoring, vitamin D/calcium 
supplement. 
Hold study 
treatment. 
Retreatment is 
acceptable if 
symptoms resolve 
completely or are 
controlled on 
prednisolone 
≤10 mg/day. 
Discontinue study 
treatment if 
symptoms persist 
with 
corticosteroid 
treatment. 

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Autoimmune 
Toxicity 
Grade 
Treatment Guidelines (Subject 
to Clinical Judgement) 
Study Drug 
Management 
3-4 
Severe or life-threatening 
symptoms: breathless at rest 
Admit to a hospital and initiate 
treatment with intravenous 
methylprednisolone 
2-4 mg/kg/day. If there is no 
improvement, or worsening after 
48 hours, add infliximab 5 mg/kg 
(if no hepatic involvement). 
Convert to oral prednisolone and 
taper over at least 2 months. 
Cover with empiric antibiotics and 
consider prophylaxis for 
Pneumocystis infection and other 
adverse steroid effects, e.g., blood 
glucose monitoring, vitamin 
D/calcium supplement. 
Discontinue study 
treatment. 
Neurological 
Toxicity 
1 
Mild symptoms 
– 
Continue study 
treatment. 
2 
Moderate symptoms 
Treat with oral prednisolone 
0.5-1 mg/kg/day. Taper over at 
least 4 weeks. 
Obtain neurology consultation. 
Hold study 
treatment; resume 
when 
resolved/improved 
to Grade 0-1. 
3-4 
Severe/life-threatening symptoms 
Initiate treatment with oral 
prednisolone or intravenous 
methylprednisolone 
1-2 mg/kg/day, depending on 
symptoms. Taper corticosteroids 
over at least 4 weeks. 
Consider azathioprine, MMF, 
cyclosporine if no response within 
72-96 hours. 
Discontinue study 
treatment. 
Colitis/Diarrhea 
1 
Mild symptoms: ≤3 liquid stools 
per day over baseline and feeling 
well 
Symptomatic management: fluids, 
loperamide, avoid high 
fiber/lactose diet. 
If Grade 1 persists for >14 days, 
manage as a Grade 2 event. 
Continue study 
treatment. 
2 
Moderate symptoms: 4-6 liquid 
stools per day over baseline, or 
abdominal pain, or blood in stool, 
or nausea, or nocturnal episodes 
Oral prednisolone 0.5 mg/kg/day 
(nonenteric coated). 
Do not wait for any diagnostic 
tests to start treatment. Taper 
steroids over 2-4 weeks. 
Consider endoscopy if symptoms 
are recurring. 
Hold study 
treatment; resume 
when 
resolved/improved 
to baseline grade. 

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Autoimmune 
Toxicity 
Grade 
Treatment Guidelines (Subject 
to Clinical Judgement) 
Study Drug 
Management 
3 
Severe symptoms: >6 liquid 
stools per day over baseline, or if 
episodic within 1 hour of eating 
Initiate intravenous 
methylprednisolone 
1-2 mg/kg/day. 
Convert to oral prednisolone and 
taper over at least 4 weeks. 
Consider prophylaxis for adverse 
steroid effects, e.g., blood glucose 
monitoring, vitamin D/calcium 
supplement. 
If no improvement in 72 hours or 
symptoms worsen, consider 
infliximab 5 mg/kg if no 
perforation, sepsis, TB, hepatitis, 
NYHA Class III/IV CHF or other 
immunosuppressive treatment: 
MMF or tacrolimus. 
Consult gastroenterologist to 
conduct colonoscopy/ 
sigmoidoscopy. 
Hold study 
treatment; 
retreatment may 
be considered 
when 
resolved/improved 
to baseline grade 
and after 
discussion with 
the study Medical 
Monitor. 
 
4 
Life-threatening symptoms 
Discontinue study 
treatment. 
Skin reactions 
1 
Skin rash, with or without 
symptoms, <10% BSA 
Avoid skin irritants and sun 
exposure; topical emollients 
recommended. 
Continue study 
treatment. 
2 
Rash covers 10%-30% of BSA 
Avoid skin irritants and sun 
exposure; topical emollients 
recommended. 
Topical steroids (moderate 
strength cream once a day or 
potent cream twice a day) ± oral or 
topical antihistamines for itch. 
Consider a short course of oral 
steroids. 
Continue study 
treatment. 
3 
Rash covers >30% BSA or Grade 
2 with substantial symptoms 
Avoid skin irritants and sun 
exposure; topical emollients 
recommended. 
Initiate steroids as follows based 
on clinical judgement: 
For moderate symptoms: oral 
prednisolone 0.5-1 mg/kg/day for 
3 days then taper over 2-4 weeks. 
For severe symptoms: 
intravenous methylprednisolone 
0.5-1 mg/kg/day; convert to oral 
prednisolone and taper over at 
least 4 weeks. 
Hold study 
treatment. 
Re-treat when AE 
is resolved or 
improved to mild 
rash (Grade 1-2) 
after discussion 
with the study 
Medical Monitor. 
 

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Autoimmune 
Toxicity 
Grade 
Treatment Guidelines (Subject 
to Clinical Judgement) 
Study Drug 
Management 
4 
Skin sloughing >30% BSA with 
associated symptoms (e.g., 
erythema, purpura, epidermal 
detachment) 
Initiate intravenous 
methylprednisolone 
1-2 mg/kg/day. Convert to oral 
prednisolone and taper over at 
least 4 weeks. 
Admit to a hospital and seek 
urgent dermatology consultation. 
Discontinue study 
treatment. 
Hepatitis 
1 
ALT or AST >ULN to 3 x ULN 
Check LFTs within 1 week and 
before the next dose; check LFTs 
to verify that there has been no 
worsening. 
If LFTs are worsening, recheck 
every 48-72 hours until 
improvement is seen. 
Continue study 
treatment if LFTs 
are unchanged or 
improving. 
Hold study 
treatment if LFTs 
are worsening 
until improvement 
is seen. 
2 
ALT or AST 3-5 x ULN 
Recheck LFTs every 48-72 hours. 
For persistent ALT/AST elevation: 
consider oral prednisolone 
0.5-1 mg/kg/day for 3 days, then 
taper over 2-4 weeks. 
For rising ALT/AST: start oral 
prednisolone 1 mg/kg/day and 
taper over 2-4 weeks; re-escalate 
dose if LFTs worsen, depending 
on clinical judgement.  
Hold study 
treatment; 
treatment may be 
resumed when 
resolved/improved 
to baseline Grade 
and prednisolone 
tapered to 
≤10 mg. 
3 
ALT or AST 5-20 x ULN 
ALT/AST <400 IU/L and normal 
bilirubin/INR/albumin: Initiate 
oral prednisolone 1 mg/kg and 
taper over at least 4 weeks. 
ALT/AST >400 IU/L or raised 
bilirubin/INR/low albumin: Initiate 
intravenous (methyl)prednisolone 
2 mg/kg/day. 
When LFTs improve to Grade 2 or 
lower, convert to oral prednisolone 
and taper over at least 4 weeks.  
Hold study 
treatment until 
improved to 
baseline grade; 
reintroduce only 
after discussion 
with the study 
Medical Monitor.  
 
4 
ALT or AST >20 x ULN 
Initiate intravenous 
methylprednisolone 2 mg/kg/day. 
Convert to oral prednisolone and 
taper over at least 6 weeks.  
Discontinue study 
treatment. 

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Autoimmune 
Toxicity 
Grade 
Treatment Guidelines (Subject 
to Clinical Judgement) 
Study Drug 
Management 
Worsening LFTs despite steroids: 
• 
If on oral prednisolone, change to pulsed intravenous methylprednisolone. 
• 
If on intravenous methylprednisolone, add mycophenolate mofetil (MMF) 
500 to 1000 mg twice a day. 
• 
If worsens on MMF, consider addition of tacrolimus. 
Duration and dose of steroid required will depend on severity of event. 
Nephritis 
1 
Creatinine 1.5 x baseline 
or >ULN to 1.5 x ULN 
Repeat creatinine weekly. 
If symptoms worsen, manage as 
per criteria below. 
Continue study 
treatment. 
2 
Creatinine >1.5-3 x baseline 
or >1.5-3 x ULN 
Ensure hydration and review 
creatinine in 48-72 hours; if not 
improving, consider creatinine 
clearance measurement by 24-hour 
urine collection. 
Discuss with nephrologist the need 
for kidney biopsy. 
If attributed to study drug, initiate 
oral prednisolone 0.5-1 mg/kg and 
taper over at least 2 weeks. 
Repeat creatinine/U&E every 48-
72 hours. 
Hold study 
treatment. 
If not attributed to 
drug toxicity, 
restart treatment. 
If attributed to 
study drug and 
resolved/improved 
to baseline grade: 
Restart study drug 
if tapered to 
<10 mg 
prednisolone. 
3 
Creatinine >3 x baseline 
or >3-6 x ULN 
Hospitalize patient for monitoring 
and fluid balance; repeat creatinine 
every 24 hours; refer to a 
nephrologist and discuss need for 
biopsy. 
If worsening, initiate intravenous 
(methyl)prednisolone 1-2 mg/kg. 
Taper corticosteroids over at least 
4 weeks. 
Hold study 
treatment until the 
cause is 
investigated.  
If study drug 
suspected: 
Discontinue study 
treatment. 
 
4 
Creatinine >6 x ULN 
As per Grade 3, patient should be 
managed in a hospital where renal 
replacement therapy is available. 
Discontinue study 
treatment. 
Diabetes/ 
Hyperglycemia 
1 
Fasting glucose value ULN to 
160 mg/dL; ULN to 8.9 mmol/L 
Monitor closely and treat 
according to local guideline. 
Check for C-peptide and 
antibodies against glutamic acid 
decarboxylase and islet cells are 
recommended. 
Continue study 
treatment. 

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Autoimmune 
Toxicity 
Grade 
Treatment Guidelines (Subject 
to Clinical Judgement) 
Study Drug 
Management 
2 
Fasting glucose value 
160-250 mg/dL; 8.9-13.9 mmol/L 
Obtain a repeat blood glucose level 
at least every week. Manage 
according to local guideline. 
Continue study 
treatment or hold 
treatment if 
hyperglycemia is 
worsening. 
Resume treatment 
when blood 
glucose is 
stabilized at 
baseline or 
Grade 0-1. 
3 
Fasting glucose value 
250-500 mg/dL; 13.9-
27.8 mmol/L 
Admit patient to hospital and refer 
to a diabetologist for 
hyperglycemia management. 
Corticosteroids may exacerbate 
hyperglycemia and should be 
avoided. 
Hold study 
treatment until 
patient is 
hyperglycemia 
symptom-free, 
and blood glucose 
has been 
stabilized at 
baseline or 
Grade 0-1. 
 
4 
Fasting glucose 
value >500 mg/dL; >27.8 mmol/L 
Admit patient to hospital and 
institute local emergency diabetes 
management. 
Refer the patient to a diabetologist 
for insulin maintenance and 
monitoring. 
Hold study 
treatment until 
patient is 
hyperglycemia 
symptom-free, 
and blood glucose 
has been 
stabilized at 
baseline or 
Grade 0-1. 
 
Ocular Toxicity 
1 
Asymptomatic eye 
examination/test abnormality 
Consider alternative causes and 
prescribe topical treatment as 
required. 
Continue study 
treatment. 
2 
Anterior uveitis or mild 
symptoms 
Refer patient to an 
ophthalmologist for assessment 
and topical corticosteroid 
treatment. 
Consider a course of oral steroids. 
Continue study 
treatment or hold 
treatment if 
symptoms worsen 
or if there are 
symptoms of 
visual disturbance. 

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Autoimmune 
Toxicity 
Grade 
Treatment Guidelines (Subject 
to Clinical Judgement) 
Study Drug 
Management 
3 
Posterior uveitis/panuveitis or 
significant symptoms 
Refer patient urgently to an 
ophthalmologist. Initiate oral 
prednisolone 1-2 mg/kg and taper 
over at least 4 weeks. 
Hold study 
treatment until 
improved to 
Grade 0-1; 
reintroduce only 
after discussion 
with the study 
Medical Monitor. 
 
4 
Blindness (at least 20/200) in the 
affected eyes 
Initiate intravenous 
(methyl)prednisolone 2 mg/kg/day. 
Convert to oral prednisolone and 
taper over at least 4 weeks. 
Discontinue study 
treatment. 
Pancreatitis 
2 
Asymptomatic, blood test 
abnormalities 
Monitor pancreatic enzymes. 
Continue study 
treatment. 
3 
Abdominal pain, nausea and 
vomiting 
Admit to hospital for urgent 
management. Initiate intravenous 
(methyl)prednisolone 
1-2 mg/kg/day. Convert to oral 
prednisolone when amylase/lipase 
improved to Grade 2 and taper 
over at least 4 weeks. 
Hold study 
treatment; 
reintroduce only 
after discussion 
with the study 
Medical Monitor. 
 
4 
Acute abdominal pain, surgical 
emergency 
Admit to hospital for emergency 
management and appropriate 
referral.  
Discontinue study 
treatment. 
Arthritis 
1 
Mild pain with inflammation, 
swelling 
Management per local guideline.  
Continue study 
treatment. 
2 
Moderate pain with 
inflammation, swelling, limited 
instrumental (fine motor) 
activities 
Management as per local 
guideline. Consider referring 
patient to a rheumatologist. 
If symptoms worsen on treatment, 
manage as a Grade 3 event. 
Continue 
treatment or, if 
symptoms 
continue to 
worsen, hold 
study treatment 
until symptoms 
improve to 
baseline or 
Grade 0-1. 

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Autoimmune 
Toxicity 
Grade 
Treatment Guidelines (Subject 
to Clinical Judgement) 
Study Drug 
Management 
3 
Severe pain with inflammation or 
permanent joint damage, daily 
living activity limited 
Refer patient urgently to a 
rheumatologist for assessment and 
management. 
Initiate oral prednisolone 
0.5-1 mg/kg and taper over at least 
4 weeks. 
Hold study 
treatment unless 
improved to 
Grade 0-1; 
reintroduce only 
after discussion 
with the study 
Medical Monitor. 
 
Mucositis/ 
stomatitis 
1 
Test findings only or minimal 
symptoms 
Consider topical treatment or 
analgesia as per local guideline. 
Continue study 
treatment. 
2 
Moderate pain, reduced oral 
intake, limited instrumental 
activities 
As per local guidelines, treat with 
analgesics, topical treatments, and 
oral hygiene care. 
Ensure adequate hydration. 
If symptoms worsen or there is 
sepsis or bleeding, manage as a 
Grade 3 event. 
Continue study 
treatment. 
3 
Severe pain, limited food and 
fluid intake, daily living activity 
limited 
Admit to hospital for appropriate 
management. 
Initiate intravenous 
(methyl)prednisolone 
1-2 mg/kg/day. 
Convert to oral prednisolone when 
symptoms improve to Grade 2 and 
taper over at least 4 weeks. 
Hold study 
treatment until 
improved to 
Grade 0-1. 
 
4 
Life-threatening complications or 
dehydration 
Admit to hospital for emergency 
care. Consider intravenous 
corticosteroids if not 
contraindicated by infection. 
Discontinue study 
treatment. 
Myositis/ 
Rhabdomyolysis 
1 
Mild weakness with/without pain 
Prescribe analgesics. 
If CK is significantly elevated and 
patient has symptoms, consider 
oral steroids and treat as Grade 2. 
Continue study 
treatment. 
2 
Moderate weakness with/without 
pain 
If CK is 3 x ULN or worse, initiate 
oral prednisolone 0.5-1 mg/kg and 
taper over at least 4 weeks. 
Hold study 
treatment until 
improved to 
Grade 0-1. 

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Autoimmune 
Toxicity 
Grade 
Treatment Guidelines (Subject 
to Clinical Judgement) 
Study Drug 
Management 
3-4 
Severe weakness, limiting self-
care 
Admit to hospital and initiate oral 
prednisolone 1 mg/kg. Consider 
bolus intravenous 
(methyl)prednisolone and 1-
2 mg/kg/day maintenance for 
severe activity restriction or 
dysphagia. 
If symptoms do not improve, add 
immunosuppressant therapy. 
Taper oral steroids over at least 
4 weeks. 
For Grade 3: Hold 
study treatment 
until improved to 
Grade 0-1. 
Discontinue upon 
any evidence of 
myocardial 
involvement. 
 
Myocarditis a 
<2 
Asymptomatic but significantly 
increased CK-MB or increased 
troponin OR clinically significant 
intraventricular conduction delay 
Initiate cardiac evaluation under 
close monitoring with repeat 
serum testing and including ECG, 
cardiac echo/MUGA, and/or other 
interventions per institutional 
guidelines; consider referral to a 
cardiologist. 
If diagnosis of myocarditis is 
confirmed, treat as Grade 2. 
Hold study 
treatment. 
If a diagnosis of 
myocarditis is 
confirmed and 
considered 
immune-related, 
permanently 
discontinue study 
treatment in 
patients with 
moderate or 
severe symptoms. 
Patients with no 
symptoms or mild 
symptoms may 
not restart 
tislelizumab 
unless cardiac 
parameters have 
returned to 
baseline and after 
discussion with 
the study Medical 
Monitor. 
2 
Symptoms on mild-moderate 
exertion 
Admit to hospital and initiate oral 
prednisolone or intravenous 
(methyl)prednisolone at 
1-2 mg/kg/day. Consult with a 
cardiologist and manage symptoms 
of cardiac failure according to 
local guidelines. 
If no immediate response, change 
to pulsed doses of 
(methyl)prednisolone 1 g/day and 
add MMF, infliximab, or anti-
thymocyte globulin. 
3 
Severe symptoms with mild 
exertion 
Hold study 
treatment. 
If a diagnosis of 

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Autoimmune 
Toxicity 
Grade 
Treatment Guidelines (Subject 
to Clinical Judgement) 
Study Drug 
Management 
4 
Life-threatening 
myocarditis is 
confirmed and 
considered 
immune related, 
permanently 
discontinue study 
treatment in 
patients with 
moderate or 
severe symptoms. 
Patients with no 
symptoms or mild 
symptoms may 
not restart 
tislelizumab 
unless cardiac 
parameters have 
returned to 
baseline and after 
discussion with 
the study Medical 
Monitor. 
Abbreviations: AE = adverse event; ALT = alanine aminotransferase; AST = aspartate aminotransferase; 
BSA = body surface area; CHF = congestive heart failure; CK = creatine kinase; CK-MB = creatine kinase cardiac 
isoenzyme; ECG = electrocardiogram; INR = international normalized ratio; LFT = liver function test; 
MMF = mycophenolate mofetil; MUGA = multigated acquisition scan; NYHA = New York Heart Association; T4 
= thyroxine; TB = tuberculosis; TFT = thyroid function test; TSH = thyroid-stimulating hormone; U&E = urea and 
electrolytes; ULN = upper limit of normal. 
a If clinically significant cardiac enzyme abnormalities are detected during laboratory assessment and serial cardiac 
enzyme assessments pose logistical hardship for the patient, then patient hospitalization should strongly be 
considered until immune-related myocarditis has been ruled out. 
 
Note: Recommendation for diagnostic evaluation and management of irAEs is based on European Society for 
Medical Oncology (ESMO) and American Society of Clinical Oncology (ASCO) guidelines (Haanen, Carbonnel et 
al. 2017, Brahmer, Lacchetti et al. 2018), and common immune-related toxicities are detailed in this appendix. For 
any AEs not included in this appendix, please refer to the ASCO Clinical Practice Guideline (Brahmer, Lacchetti et 
al. 2018) for further guidance on diagnostic evaluation and management of immune-related toxicities. 

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APPENDIX 9. CHRONIC KIDNEY DISEASE EPIDEMIOLOGY 
COLLABORATION (CKD-EPI) EQUATION 
In adults, the most widely-used equations for estimating glomerular filtration rate (eGFR) from 
serum creatinine are the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) 
equation (Levey, Stevens et al. 2009) and the Modification of Diet in Renal Disease (MDRD) 
Study equation. The National Kidney Disease Education Program (NKDEP) calculators rely on 
creatinine determinations which are isotope dilution mass spectrometry (IDMS) traceable. All 
laboratories should be using creatinine methods calibrated to be IDMS traceable. 
This CKD-EPI equation calculator should be used when serum creatinine (Scr) is reported in 
mg/dL. 
GFR = 141 × min (Scr /κ, 1)α × max(Scr /κ, 1)-1.209 × 0.993Age × 1.018 [if female] × 1.159 [if 
black] 
where: 
Scr is serum creatinine in mg/dL, 
κ is 0.7 for females and 0.9 for males, 
α is -0.329 for females and -0.411 for males, 
min indicates the minimum of Scr /κ or 1, and 
max indicates the maximum of Scr /κ or 1. 
The equation does not require weight because the results are reported normalized to 1.73 m2 
body surface area, which is an accepted average adult surface area. 
The online calculator for CKD-EPI can be found here: 
https://www.niddk.nih.gov/health-information/communication-programs/nkdep/laboratory-
evaluation/glomerular-filtration-rate-calculators 

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APPENDIX 10. CONTRACEPTION GUIDELINES AND DEFINITIONS 
OF “WOMEN OF CHILDBEARING POTENTIAL,” “NO 
CHILDBEARING POTENTIAL” 
Contraception Guidelines 
The Clinical Trials Facilitation Group recommendations related to contraception and pregnancy 
testing in clinical trials include the use of highly effective forms of birth control (CTFG 2014). 
These methods include the following: 
• Combined (estrogen- and progestogen-containing) hormonal contraception associated 
with the inhibition of ovulation 
o Oral, intravaginal, or transdermal 
• Progestogen-only hormonal contraception associated with the inhibition of ovulation 
o Oral, injectable, implantable 
Note: Oral birth control pills are not considered a highly effective form of birth 
control, and if they are selected, they must be used with a second, barrier method 
of contraception such as condoms with or without spermicide. 
• An intrauterine device 
• Intrauterine hormone-releasing system 
• Bilateral tubal occlusion 
• Vasectomized partner 
Note: This is only considered a highly effective form of birth control when the 
vasectomized partner is the sole partner of the study patient and there has been a medical 
assessment confirming surgical success. 
o A sterile male is one for whom azoospermia, in a semen sample, has been 
demonstrated as definitive evidence of infertility. 
• Sexual abstinence (defined as refraining from heterosexual intercourse during the entire 
period of risk associated with the study treatment) 
Note: Total sexual abstinence should only be used as a contraceptive method if it is in 
line with the patients’ usual and preferred lifestyle. Periodic abstinence (e.g., calendar, 
ovulation, sympto-thermal, post-ovulation methods), declaration of abstinence for the 
duration of exposure to study drug, and withdrawal are not acceptable methods of 
contraception. 
Of note, barrier contraception (including male and female condoms with or without spermicide) 
is not considered a highly effective method of contraception, and if used, this method must be 
used in combination with one of the highly effective forms of birth control listed above. 
Definitions of “Women of Childbearing Potential,” “Women of No Childbearing Potential” 
As defined in this protocol, “women of childbearing potential” are female patients who are 
physiologically capable of becoming pregnant. 

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Conversely, “women of no childbearing potential” are defined as female patients meeting any of 
the following criteria: 
• Surgically sterile (i.e., through bilateral salpingectomy, bilateral oophorectomy, or 
hysterectomy) 
• Postmenopausal, defined as: 
o ≥55 years of age with no spontaneous menses for ≥12 months OR 
o <55 years of age with no spontaneous menses for ≥12 months AND with 
postmenopausal follicle-stimulating hormone concentration >30 IU/mL and all 
alternative medical causes for the lack of spontaneous menses for ≥12 months 
have been ruled out, such as polycystic ovarian syndrome, hyperprolactinemia, 
etc. 
If a follicle-stimulating hormone measurement is required to confirm postmenopausal state, 
concomitant use of hormonal contraception or hormonal replacement therapy should be 
excluded. 
Adapted from (CTFG 2014). 

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APPENDIX 11. NCI-CTCAE V5.0 INFUSION-RELATED REACTIONS 
Adverse 
Event 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Infusion-
related 
reaction 
Mild transient 
reaction; infusion 
interruption not 
indicated; 
intervention not 
indicated 
Therapy or infusion 
interruption indicated 
but responds promptly 
to symptomatic 
treatment (e.g., 
antihistamines, 
NSAIDS, narcotics, IV 
fluids); prophylactic 
medications indicated 
for ≤24 hrs 
Prolonged (e.g., not 
rapidly responsive to 
symptomatic 
medication and/or brief 
interruption of 
infusion); recurrence of 
symptoms following 
initial improvement; 
hospitalization 
indicated for clinical 
sequelae 
Life-threatening 
consequences; 
urgent 
intervention 
indicated 
Death 
Definition: A disorder characterized by an adverse reaction to the infusion of pharmacological or biological substances. 
Allergic 
reaction 
Systemic 
intervention not 
indicated 
Oral intervention 
indicated 
Bronchospasm; 
hospitalization 
indicated for clinical 
sequelae; intravenous 
intervention indicated 
Life-threatening 
consequences; 
urgent 
intervention 
indicated 
Death 
Definition: A disorder characterized by an adverse local or general response from exposure to an allergen. 
Anaphylaxis 
- 
- 
Symptomatic 
bronchospasm, with or 
without urticaria; 
parenteral intervention 
indicated; allergy-
related 
edema/angioedema; 
hypotension 
Life-threatening 
consequences; 
urgent 
intervention 
indicated 
Death 
Definition: A disorder characterized by an acute inflammatory reaction resulting from the release of histamine and histamine-
like substances from mast cells, causing a hypersensitivity immune response. Clinically, it presents with breathing difficulty, 
dizziness, hypotension, cyanosis, and loss of consciousness and may lead to death. 
Cytokine 
release 
syndrome 
Fever with or 
without 
constitutional 
symptoms 
Hypotension 
responding to fluids; 
hypoxia responding to 
<40% O2 
Hypotension managed 
with one pressor; 
hypoxia requiring 
≥40% O2 
Life-threatening 
consequences; 
pressor or 
ventilator support 
indicated 
Death 
Definition: A disorder characterized by fever, tachypnea, headache, tachycardia, hypotension, rash, and/or hypoxia caused by 
the release of cytokines. 
Abbreviations: IV = intravenous; NSAID = nonsteroidal anti-inflammatory drug; O2 = oxygen. 

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APPENDIX 12. MANAGEMENT OF DKN-01 INFUSION-RELATED 
REACTIONS 
Grade  
Management 
Grade 1 
• 
Slow the infusion rate by 50%. 
• 
Monitor the patient for worsening of condition. 
• 
For subsequent infusions, premedicate with diphenhydramine hydrochloride 50 mg IV (or equivalent); 
additional premedication may be administered at the Investigator’s discretion. 
Grade 2 
• 
Stop the infusion. 
• 
Administer diphenhydramine hydrochloride 50 mg IV (or equivalent), acetaminophen 650 mg orally 
for fever, and oxygen.  
• 
Resume the infusion at 50% of the prior rate once the infusion-related reaction has resolved or 
decreased to Grade 1. 
• 
Monitor for worsening of condition. 
• 
For subsequent infusions, premedicate with diphenhydramine hydrochloride 50 mg IV (or equivalent); 
additional premedication may be administered at the Investigator’s discretion. 
• 
For a second Grade 1 or 2 infusion-related reaction, administer dexamethasone 10 mg IV 
(or equivalent); then, for subsequent infusions, premedicate with diphenhydramine hydrochloride 
50 mg IV (or equivalent), acetaminophen 650 mg orally, and dexamethasone 10 mg IV (or equivalent). 
Grade 3 
• 
Stop the infusion and disconnect the infusion tubing from the patient. 
• 
Administer diphenhydramine hydrochloride 50 mg IV (or equivalent), dexamethasone 10 mg IV (or 
equivalent), bronchodilators for bronchospasm, and other medications/treatment as medically 
indicated. 
• 
Patients who have a Grade 3 infusion-related reaction with premedication will not receive further 
DKN-01 treatment but will continue to be followed on the protocol. 
Grade 4 
• 
Stop the infusion and disconnect the infusion tubing from the patient. 
• 
Administer diphenhydramine hydrochloride 50 mg IV (or equivalent), dexamethasone 10 mg IV (or 
equivalent), and other medications/treatment as medically indicated. 
• 
Give epinephrine or bronchodilators as indicated. 
• 
Hospital admission for observation may be indicated. 
• 
Patients who have a Grade 4 infusion-related reaction with or without premedication will not receive 
further DKN-01 treatment but will continue to be followed on the protocol. 
Abbreviations: IV = intravenous 

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APPENDIX 13. Management of Tislelizumab Infusion-Related Reaction and 
Hypersensitivity Reaction 
Managing Infusion-Related Reactions 
Patients should be closely monitored for infusion-related reactions. Immediate access to an 
Intensive Care Unit (ICU) or equivalent environment and appropriate medical therapy (including 
epinephrine, corticosteroids, intravenous antihistamines, bronchodilators, and oxygen) must be 
available to treat infusion-related reactions. 
Treatment modifications for symptoms of infusion-related reactions due to study drug(s) is 
provided in Table 18. 
Table 18: 
Treatment Modifications for Symptoms of Infusion-Related Reactions Due to 
Study Drug(s) 
NCI-CTCAE Grade 
Treatment Modification for Tislelizumab 
Grade 1 - mild 
Mild transient reaction; infusion interruption not 
indicated; intervention not indicated. 
Decrease infusion rate by 50%. Any worsening is 
closely monitored. Medical management as 
needed. 
Subsequent infusions should be given after 
premedication and at the reduced infusion rate. 
Grade 2 - moderate 
Therapy or infusion interruption indicated but 
responds promptly to symptomatic treatment (e.g., 
antihistamines, NSAIDs, narcotics, intravenous 
fluids); prophylactic medications indicated for 
≤24 hours. 
Stop infusion. Infusion may be resumed at 50% of 
previous rate once infusion-related reaction has 
resolved or decreased to Grade 1 in severity. Any 
worsening is closely monitored. Proper medical 
management should be instituted as described 
below. 
Subsequent infusions should be given after 
premedication and at the reduced infusion rate. 
Grade 3 – severe 
Prolonged (e.g., not rapidly responsive to 
symptomatic medication and/or brief interruption 
of infusion); recurrence of symptoms following 
initial improvement; hospitalization indicated for 
clinical sequelae. 
Immediately stop the infusion. Proper medical 
management should be instituted as described 
below. 
The patient should be withdrawn from study 
drug(s) treatment. 
Grade 4 – life threatening 
Life-threatening consequences; urgent 
intervention indicated. 
Immediately stop the infusion. Proper medical 
management should be instituted as described 
below. 
The patient should be withdrawn from study 
drug(s) treatment. 
Hospitalization is recommended. 
Abbreviations: NCI-CTCAE = National Cancer Institute Common Terminology Criteria for Adverse Event; 
NSAIDs = nonsteroidal anti-inflammatory drugs. 
Once the tislelizumab infusion rate has been decreased by 50% or suspended due to an infusion-
related reaction, it must remain decreased for all subsequent infusions and be administered with 

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premedication. If the patient has a second infusion-related reaction (≥Grade 2) on the slower 
infusion rate, infusion should be discontinued, and the patient should be withdrawn from 
tislelizumab treatment. 
NCI-CTCAE Grade 1 or 2 infusion reaction: Proper medical management should be instituted 
as indicated per the type of reaction. This includes, but is not limited to, an antihistamine (e.g., 
diphenhydramine or equivalent), antipyretic (e.g., paracetamol or equivalent), and if considered 
indicated, oral or intravenous glucocorticoids, epinephrine, bronchodilators, and oxygen. In the 
next cycle, patients should receive oral premedication with an antihistamine (e.g., 
diphenhydramine or equivalent) and an antipyretic (e.g., paracetamol or equivalent), and they 
should be closely monitored for clinical signs and symptoms of an infusion reaction. 
NCI-CTCAE Grade 3 or 4 infusion reaction: Proper medical management should be instituted 
immediately, as indicated per type and severity of the reaction. This includes, but is not limited 
to, oral or intravenous antihistamines, antipyretics, glucocorticoids, epinephrine, bronchodilators, 
and oxygen. 
Severe Hypersensitivity Reactions and Flu-Like Symptoms 
If hypersensitivity reaction occurs, the patient must be treated according to the best available 
medical practice as described in the complete guideline for emergency treatment of anaphylactic 
reactions according to the Working Group of the Resuscitation Council (UK) (Soar, Pumphrey et 
al. 2008). Patients should be instructed to report any delayed reactions to the Investigator 
immediately. 
In the event of a systemic anaphylactic/anaphylactoid reaction the infusion must be immediately 
stopped, and the patient discontinued from the study. Systemic anaphylactic/anaphylactoid 
reactions typically manifest within minutes following administration of the drug/antigen and are 
characterized by respiratory distress; laryngeal edema; and/or intense bronchospasm; and often 
followed by vascular collapse or shock without antecedent respiratory difficulty; cutaneous 
manifestations such as pruritus and urticaria with/without edema; and gastrointestinal 
manifestations such as nausea, vomiting, crampy abdominal pain, and diarrhea. 
The patient will be administered epinephrine injection and dexamethasone infusion if 
hypersensitivity reaction is observed. The patient should then be placed on monitor immediately, 
and ICU should be alerted for possible transfer if needed. 
For prophylaxis of flu-like symptoms, a dose of 25 mg indomethacin or a comparable dose of 
nonsteroidal anti-inflammatory drugs (i.e., 600 mg ibuprofen, 500 mg naproxen sodium) may be 
administered 2 hours before and 8 hours after the start of each dose of study drugs(s) infusion. 
Alternative treatments for fever (i.e., paracetamol) may be given to patients at the discretion of 
the Investigator.