Phase III, Open-label, Single-dose, Multi-center, Multinational Trial Investigating a Serotype 5 Adeno-associated Viral Vector Containing the Padua Variant of a Codon-optimized Human Factor IX Gene (AAV5-hFIXco-Padua, AMT-061) Administered to Adult Subjects With Severe or Moderately Severe Hemophilia B
Phase: PHASE3
Conditions: Hemophilia B
Sponsor: CSL Behring

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 1 of 150 
CLINICAL TRIAL PROTOCOL 
Trial Title: 
Phase III, open-label, single-dose, multi-center multinational trial 
investigating a serotype 5 adeno-associated viral vector containing the 
Padua variant of a codon-optimized human factor IX gene 
(AAV5-hFIXco-Padua, AMT-061) administered to adult subjects with 
severe or moderately severe hemophilia B 
Short Title: 
Phase III trial of AMT-061 in subjects with severe or moderately severe 
hemophilia B. 
Protocol Identification: 
CSL222_3001 (formerly CT-AMT-061-02) 
EU CT No.: 
2024-510738-42 
EudraCT No.: 
2017-004305-40 
Name of Investigational Product: 
CSL222 (formerly AMT-061 [AAV5-hFIXco-Padua; 
etranacogene dezaparvovec]) 
IND No. 
016248 
Indication Studied: 
Hemophilia B 
Developmental Phase of Trial: 
III 
Name of the Sponsor/Company: 
CSL Behring LLC 
1020 First Avenue 
King of Prussia 
Pennsylvania 19406, USA 
Name of the Monitoring CRO: 
Medpace (with oversight by CSL Behring) 
Coordinating Investigator: 
Steven Pipe, MD 
Protocol Version and Date: 
Version 9.0 (Amendment 8.0) 12 Feb 2024 
 
Version 8.0 (Amendment 7.0) 07 Feb 2022 
 
Version 7.0 (Amendment 6.0) 28 Jun 2021 
 
Version 6.0 (Amendment 5.0) 04 Feb 2021 
 
Version 5.0 (Amendment 4.0) 15 Oct 2020 
 
Version 4.0 (Amendment 3.0) 30 Aug 2019 
 
Version 3.0 (Amendment 2.0) 07 Dec 2018 
 
Version 2.0 (Amendment 1.0) 02 Apr 2018 
 
Version 1.0 (Original) 16 Feb 2018 
This trial, including the archiving, will be conducted in compliance with Good Clinical Practice (GCP) according 
to the International Council for Harmonisation (ICH) Harmonised Tripartite Guideline (CPMP/ICH/135/95) 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
Protocol ID: CSL222_3001 
CSL Behring 
CLINICAL TRIAL PROTOCOL SIGNATURE PAGE 
Sponsor's Approval 
Version: 9.0 
Page 2 of 150 
Date: 
 
Date: 12 Feb 2024 
PPD
PPD
PPD

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 3 of 150 
INVESTIGATOR’S ACKNOWLEDGEMENT 
I have read this  
Protocol ID: CSL222_3001 (formerly CT-AMT-061-02) 
Title: Phase III, open-label, single-dose, multi-center multinational trial investigating a serotype 
5 adeno-associated viral vector containing the Padua variant of a codon-optimized human factor 
IX gene (AAV5-hFIXco-Padua, AMT-061) administered to adult subjects with severe or 
moderately severe hemophilia B. 
I have fully discussed the objectives of this trial and the contents of this protocol with the 
Sponsor’s representative. 
I understand that the information in this protocol is confidential and should not be disclosed, 
other than to those directly involved in the execution or the scientific/ethical review of the trial, 
without written authorization from the Sponsor. It is, however, permissible to provide the 
information contained herein to a subject in order to obtain their consent to participate. 
I agree to conduct this trial according to this protocol and any trial specific manuals, to comply 
with its requirements, to subject to ethical and safety considerations and guidelines, and to 
conduct the trial in accordance with International Council for Harmonisation guidelines on Good 
Clinical Practice and with the applicable regulatory requirements. 
I understand that failure to comply with the requirements of the protocol may lead to termination 
of my participation as an Investigator for this trial. 
I understand that the Sponsor may decide to suspend or prematurely terminate the trial at any 
time for whatever reason; such a decision will be communicated to me in writing. Conversely, 
should I decide to withdraw from execution of the trial, I will communicate my intention 
immediately in writing to the Sponsor. 
Investigator Name, Address, and 
Telephone Number: 
(please handwrite, print or type) 
 
 
 
 
 
 
Signature: 
 
 
 
Date: 
 
 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 4 of 150 
SUMMARY OF CHANGES (PROTOCOL HISTORY) 
Current Protocol Amendment 
Summary of Change(s) Since Last Version of Approved Protocol: Section 13.2 
Amendment Number: 
8.0 (Version 9.0) 
Amendment Date: 
12 Feb 2024 
Global/Country/Site-Specific:  
Global 
 
List of All Previous Amendments 
Summary of Change(s) for Previous Amendments: Section 13.3 
Amendment Number 
Date of Amendment 
Global/Country/Site-Specific 
7.0 (Version 8.0) 
07 Feb 2022 
Global 
6.0 (Version 7.0) 
28 Jun 2021 
Global 
5.0 (Version 6.0) 
04 Feb 2021 
Global 
4.0 (Version 5.0) 
15 Oct 2020 
Global 
3.0 (Version 4.0) 
30 Aug 2019 
Global 
2.0 (Version 3.0) 
07 Dec 2018 
Global 
1.0 (Version 2.0) 
02 Apr 2018 
Global 
0.0 (Version 1.0) 
16 Feb 2018 
Global 
 
List of All Addenda 
Date of Addendum 
Global/Country/Site-Specific 
27 Mar 2019 
Germany (consolidated into global Protocol Amendment 8.0 
[Version 9.0]) 
27 Feb 2019 
France (no longer in effect; trial terminated in France) 
 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 5 of 150 
EMERGENCY CONTACT INFORMATION 
In the event of a serious adverse event (SAE) or an adverse event (AE) qualifying for special 
notification, the Investigator must complete the Clinical Trial Serious Adverse Events Form in 
the electronic case report form (eCRF) within 24 hours of becoming aware of the event. In case 
the eCRF is temporarily unavailable, the back-up paper SAE form should be completed and 
submitted to CSL Behring within 24 hours of becoming aware of the event. 
CSL Global Clinical Safety & Pharmacovigilance: 
Email: 
Adverse.Events.Global@cslbehring.com 
Fax: 
USA: + 1 610 878 4487 
AUS: + 61 3 9389 1095 
GER: + 49 6421 39 4775 
 
For protocol- or medical-related issues during normal business hours as well as outside of normal 
business hours, the Investigator must contact the Medpace and/or CSL Behring Medical 
Directors.  
A list of personnel and organizations responsible for the conduct of the trial, including the 
Medpace and CSL Behring Medical Directors, will be supplied to clinical trial sites as part of the 
Investigator’s Site File (ISF). This list will be updated by CSL Behring LLC (or delegate) and 
provided to the clinical trial sites, as needed. 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
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TABLE OF CONTENTS 
1 
INTRODUCTION ...................................................................................................................................... 36 
1.1 
Condition Background and Current Treatment ...................................................................................... 36 
1.2 
Gene Therapy Therapeutic Concept ....................................................................................................... 37 
1.3 
Investigational Product Background ....................................................................................................... 37 
1.3.1 
Preclinical Information ..................................................................................................................... 37 
1.3.2 
Preliminary Clinical Information for CSL222 and Clinical Information for CSL220 ...................... 40 
1.3.2.1 
Preliminary Clinical Evidence for Efficacy and Safety of Components of CSL222 ................. 40 
1.3.2.2 
Results of CSL220_1001 (Formerly CT-AMT-060-01) ........................................................... 44 
1.3.2.3 
Interim Results for CSL222_2001 (Formerly CT-AMT-061-01) ............................................. 44 
1.4 
Rationale for the Trial............................................................................................................................. 45 
1.5 
Risk/Benefit Considerations ................................................................................................................... 47 
1.5.1 
Risk of Infusion-related Toxicity ...................................................................................................... 47 
1.5.2 
Risk of Immune Mediated Neutralization of the AAV5 Gene Therapeutic Vector .......................... 47 
1.5.3 
Risk of Immune Mediated Liver Toxicity ........................................................................................ 48 
1.5.4 
Risks to Third Parties and the Environment Related to Shedding via Body Fluids .......................... 49 
1.5.5 
Risk of Vector DNA Integration into the Host Genome ................................................................... 49 
1.5.6 
Risk of Germ-line Transmission of Vector DNA ............................................................................. 49 
1.5.7 
Risk of Off-target Expression of the Transgene................................................................................ 50 
1.5.8 
Risk of Inhibitor Formation to Protein Expressed from the Transgene ............................................ 50 
1.5.9 
Risk of Breakthrough Bleeding......................................................................................................... 50 
1.6 
Accommodations Due to the COVID-19 Pandemic ............................................................................... 51 
2 
TRIAL OBJECTIVES ............................................................................................................................... 52 
2.1 
Primary Objective ................................................................................................................................... 52 
2.2 
Secondary and Exploratory Objectives................................................................................................... 52 
2.3 
Safety Objectives .................................................................................................................................... 52 
3 
TRIAL DESIGN ......................................................................................................................................... 53 
3.1 
Overall Trial Design ............................................................................................................................... 53 
3.1.1 
Considerations Due to the COVID-19 Pandemic ............................................................................. 55 
3.2 
Trial Design Rationale ............................................................................................................................ 55 
3.3 
Trial Endpoints ....................................................................................................................................... 56 
3.3.1 
Primary Endpoint .............................................................................................................................. 56 
3.3.2 
Secondary Endpoints ........................................................................................................................ 57 
3.3.3 
Sub-study Endpoints ......................................................................................................................... 61 
3.4 
Sample Size ............................................................................................................................................ 61 
3.5 
Sites and Regions ................................................................................................................................... 61 
4 
TRIAL POPULATION.............................................................................................................................. 62 
4.1 
Inclusion Criteria .................................................................................................................................... 62 
4.2 
Exclusion Criteria ................................................................................................................................... 62 
4.3 
Reproductive Potential ........................................................................................................................... 64 
4.4 
Restrictions ............................................................................................................................................. 64 
4.5 
Withdrawal of Subject from Therapy or Assessment ............................................................................. 64 
4.5.1 
Reasons for Discontinuation ............................................................................................................. 65 
4.5.2 
Subjects “Lost to Follow-up” Prior to Last Scheduled Visit............................................................. 65 
5 
TRIAL TREATMENT .............................................................................................................................. 66 
5.1 
Treatment(s) Administered ..................................................................................................................... 66 
5.1.1 
Investigational Medicinal Product .................................................................................................... 66 
5.1.2 
Non-Investigational Medicinal Product ............................................................................................ 66 
5.2 
Identity of Investigational Medicinal Product ........................................................................................ 66 
5.3 
Dosing and Administration ..................................................................................................................... 67 
5.4 
Randomization and Blinding .................................................................................................................. 67 
5.5 
Labeling, Packaging, Storage, and Handling .......................................................................................... 67 
5.6 
Prior and Concomitant Medication/Therapy .......................................................................................... 67 
5.6.1 
Prior Medication/Therapy ................................................................................................................. 67 
5.6.2 
Concomitant Medication/Therapy .................................................................................................... 67 

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5.6.3 
Guidelines for Use of Factor IX for Subjects Undergoing Major Surgery ....................................... 69 
5.6.4 
Guidelines for Transaminase Elevations ........................................................................................... 69 
5.7 
Treatment Compliance and Drug Accountability ................................................................................... 70 
6 
TRIAL SCHEDULE AND ASSESSMENTS ........................................................................................... 72 
6.1 
Trial Schedule ......................................................................................................................................... 72 
6.1.1 
Screening (Visit S) ............................................................................................................................ 72 
6.1.2 
Lead-in Phase (Visit L1 to L-Final) .................................................................................................. 74 
6.1.3 
IMP Dose Administration (Visit D) .................................................................................................. 76 
6.1.3.1 
Pre-IMP Dose Administration (Baseline, Day 1) ...................................................................... 76 
6.1.3.2 
IMP Dose Administration ......................................................................................................... 76 
6.1.3.3 
Post-IMP Dose Administration ................................................................................................. 76 
6.1.4 
Post-Treatment Follow-up (Visit F1 to F-Final [Week 1 to Week 52/Month 12]) ........................... 76 
6.1.4.1 
Early Discontinuation ............................................................................................................... 78 
6.1.5 
Long-term Follow-up (Visit LTF1 to LTF8 [Months 18 to 60]) ...................................................... 78 
6.1.6 
Additional Visits ............................................................................................................................... 79 
6.1.7 
Additional Care of Subjects After the Trial ...................................................................................... 79 
6.1.8 
Long-term Follow-up Extension Trial (Not Part of This Trial) ........................................................ 79 
6.2 
Trial Evaluations .................................................................................................................................... 80 
6.2.1 
Demographic and Other Baseline Characteristics ............................................................................. 80 
6.2.1.1 
Demographics ........................................................................................................................... 80 
6.2.1.2 
Medical History and Concomitant Illnesses .............................................................................. 80 
6.2.1.3 
Prior and Concomitant Medication/Therapy ............................................................................. 81 
6.2.1.4 
Hemophilia B Status and History .............................................................................................. 81 
6.2.1.5 
History of Bleeding and Factor IX Use ..................................................................................... 82 
6.2.1.6 
Factor IX Gene Sequencing (Optional) ..................................................................................... 82 
6.2.2 
Efficacy Evaluations ......................................................................................................................... 82 
6.2.2.1 
Factor IX Replacement Therapy ............................................................................................... 83 
6.2.2.2 
Bleeding Episodes ..................................................................................................................... 83 
6.2.2.3 
Factor IX Activity Levels and Factor IX Protein Concentration............................................... 84 
6.2.2.4 
Patient Reported Outcome: Quality of Life Questionnaires ...................................................... 85 
6.2.2.5 
Hemophilia Joint Health Score (HJHS) .................................................................................... 87 
6.2.2.6 
Patient Reported Outcomes, Burdens, and Experiences (PROBE) Questionnaire (Optional) .. 88 
6.2.2.7 
Musculoskeletal Ultrasound (MSKUS) (Optional) ................................................................... 88 
6.2.3 
Safety Evaluations ............................................................................................................................ 89 
6.2.3.1 
Adverse Events ......................................................................................................................... 89 
6.2.3.2 
Vital Signs ................................................................................................................................. 89 
6.2.3.3 
Physical Examination (Including Height and Weight) .............................................................. 90 
6.2.3.4 
Abdominal Ultrasound .............................................................................................................. 90 
6.2.3.5 
Anti-Factor IX Antibodies ........................................................................................................ 91 
6.2.3.6 
Factor IX Inhibitors ................................................................................................................... 91 
6.2.3.7 
Factor IX Recovery ................................................................................................................... 92 
6.2.3.8 
Total (IgG and IgM) and Neutralizing Antibodies to AAV5 .................................................... 92 
6.2.3.9 
AAV5 capsid-specific T cells ................................................................................................... 92 
6.2.3.10 
Vector Genome Detection ......................................................................................................... 93 
6.2.3.11 
Inflammatory Markers .............................................................................................................. 93 
6.2.3.12 
Other Safety Laboratory Evaluations ........................................................................................ 93 
6.2.4 
Others ................................................................................................................................................ 94 
6.2.4.1 
Blood Sampling for Future Research (Optional) ...................................................................... 94 
6.2.4.2 
Tumor, Suspected Malignancy, and Liver Tissue Sampling (Optional) ................................... 95 
6.2.5 
General Information Regarding Laboratory Sampling and Results .................................................. 95 
6.2.6 
Volume of Blood to be Drawn From Each Subject .......................................................................... 97 
7 
SAFETY DEFINITIONS, REPORTING AND FOLLOW-UP .............................................................. 98 
7.1 
Adverse Event Definitions ...................................................................................................................... 98 
7.2 
Adverse Events Qualifying for Special Notification .............................................................................. 99 
7.3 
Adverse Event Assessment Definitions .................................................................................................. 99 
7.3.1 
Severity ............................................................................................................................................. 99 

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7.3.2 
Relationship to IMP ........................................................................................................................ 100 
7.4 
Reporting of Adverse Events ................................................................................................................ 101 
7.5 
Prompt Reporting of SAEs and Other Events to CSL Behring ............................................................. 101 
7.6 
Regulatory Reporting Requirements for SAEs and Other Events ......................................................... 102 
7.7 
Reporting of Pregnancies ...................................................................................................................... 102 
7.8 
Reporting of Occupational Exposure .................................................................................................... 103 
7.9 
Follow-up on Adverse Events ............................................................................................................... 103 
8 
DATA MANAGEMENT ......................................................................................................................... 104 
8.1 
Data Collection ..................................................................................................................................... 104 
8.2 
Clinical Data Management ................................................................................................................... 104 
8.3 
Study Data ............................................................................................................................................ 104 
8.3.1 
Clinical Data – CDISC Study Data Tabulation Model (SDTM) ..................................................... 105 
8.3.2 
Analysis Data – CDISC Analysis Data Model (ADaM) ................................................................. 105 
9 
STATISTICAL METHODS .................................................................................................................... 106 
9.1 
Statistical Analysis ............................................................................................................................... 106 
9.2 
Interim Analyses ................................................................................................................................... 106 
9.3 
Final Analysis ....................................................................................................................................... 106 
9.4 
Selection of Subjects to be Included in the Analyses ........................................................................... 107 
9.5 
Subject Disposition ............................................................................................................................... 107 
9.6 
Demographic and Baseline Characteristics .......................................................................................... 108 
9.7 
Investigational Product Exposure ......................................................................................................... 108 
9.8 
Prior and Concomitant Medication ....................................................................................................... 108 
9.9 
Efficacy Analyses ................................................................................................................................. 108 
9.9.1 
Primary Efficacy Endpoints ............................................................................................................ 108 
9.9.2 
Secondary Efficacy Endpoints and Order of Testing of Primary and Secondary Endpoints .......... 110 
9.9.3 
Exploratory Efficacy Endpoints ...................................................................................................... 112 
9.9.4 
Optional Sub-study Endpoints ........................................................................................................ 113 
9.10 
Safety Analyses .................................................................................................................................... 113 
9.11 
Sample Size Justification ...................................................................................................................... 114 
9.12 
Data Monitoring Committee ................................................................................................................. 114 
10 
SPONSOR’S AND INVESTIGATOR’S RESPONSIBILITIES .......................................................... 116 
10.1 
Sponsor’s Responsibilities .................................................................................................................... 116 
10.1.1 
Good Clinical Practice Compliance ................................................................................................ 116 
10.1.2 
Indemnity/Liability and Insurance .................................................................................................. 116 
10.1.3 
Public Posting of Trial Information ................................................................................................ 116 
10.1.4 
Submission of Summary of Clinical Trial Report to Competent Authorities of Member States 
Concerned and Independent Ethics Committees ............................................................................. 117 
10.1.5 
Trial Suspension, Termination, and Completion ............................................................................ 117 
10.2 
Investigator’s Responsibilities .............................................................................................................. 117 
10.2.1 
Good Clinical Practice Compliance ................................................................................................ 117 
10.2.2 
Protocol Adherence and Investigator Agreement ........................................................................... 118 
10.2.3 
Documentation and Retention of Records ...................................................................................... 118 
10.2.3.1 
Electronic Case Report Forms ................................................................................................ 118 
10.2.3.2 
Patient Reported Outcomes ..................................................................................................... 119 
10.2.3.3 
Recording, Access, and Retention of Source Data and Trial Documents ............................... 119 
10.2.3.4 
Audit/Inspection ...................................................................................................................... 119 
10.2.3.5 
Financial Disclosure ................................................................................................................ 120 
10.2.4 
Compliance to all Regional, Local, State, and National Controlled-substance, Biohazard and 
Infectious Disease Regulations and Legislation.............................................................................. 120 
10.3 
Ethical Considerations .......................................................................................................................... 120 
10.3.1 
Informed Consent ........................................................................................................................... 120 
10.3.2 
Institutional Review Board or Independent Ethics Committee ....................................................... 121 
10.3.3 
Subject Treatment Cards ................................................................................................................. 122 
10.4 
Privacy and Confidentiality .................................................................................................................. 122 
10.5 
Publication Policy ................................................................................................................................. 123 
11 
ADMINISTRATIVE ASPECTS ............................................................................................................. 124 

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11.1 
Investigator(s) ....................................................................................................................................... 124 
11.2 
International Coordinating Investigator ................................................................................................ 124 
11.3 
Clinical Trial Sites ................................................................................................................................ 124 
11.4 
Vendors ................................................................................................................................................ 124 
12 
REFERENCE LIST ................................................................................................................................. 125 
13 
APPENDICES .......................................................................................................................................... 129 
13.1 
Laboratory Information ........................................................................................................................ 129 
13.2 
Summary of Changes in Current Amendment ...................................................................................... 130 
13.3 
Previous Amendments .......................................................................................................................... 132 
 
List of In-Text Figures 
Figure 1 Study Overview .................................................................................................................................... 24 
Figure 2 Study Design ......................................................................................................................................... 24 
 
List of In-Text Tables 
Table 1 
Schedule of Events for Efficacy and Safety Evaluation, for Screening (Visit S), Lead-in (Visit L1 
to L-Final) and Treatment (Visit D) + Post-Treatment Follow-up (Visit F1 to F-Final) ...................... 25 
Table 2 
Schedule of Events for Laboratory Parameters, for Screening (Visit S), Lead-in (Visit L1 to L-
Final) and Treatment + Post-Treatment Follow-up (Visit F1 to F-Final) ............................................. 29 
Table 3 
Schedule of Events for Efficacy and Safety Evaluation, for Long-term Follow-up (Visit LTF1 to 
LTF8) .................................................................................................................................................... 32 
Table 4 
Schedule of Events for Laboratory Parameters, for Long-term Follow-up (Visit LTF1 to LTF8) ....... 34 
Table 5 
Summary of Published Clinical Experience with Components of CSL222 .......................................... 40 
Table 6 
Components of CSL222 Drug Product ................................................................................................. 66 
Table 7 
Use of Prednisolone for the Treatment of Transaminase Increase ........................................................ 70 
Table 8 
Half-Life for Infused Exogenous Factor IX Medication by Commercial Name .................................. 85 
Table 9 
Safety Laboratory Parameters Assessed at the Central and/or Local Laboratory ................................. 94 
Table 10 Timing of Reporting and Follow-up for (Serious) Adverse Events, Adverse Events for Special 
Notification, and Pregnancies ............................................................................................................. 101 
 

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LIST OF ABBREVIATIONS AND DEFINITIONS OF TERMS 
List of Abbreviations 
AAV 
Adeno-associated virus 
AAV5 
Adeno-associated viral vector serotype 5 
AAV5-hFIXco 
Recombinant adeno-associated viral vector serotype 5 containing the 
wild-type human factor IX gene, codon-optimized for optimal expression in 
humans, under control of a liver-specific promoter (CSL220 [formerly 
AMT-060]) 
AAV5-hFIXco-
Padua 
Recombinant adeno-associated viral vector serotype 5 containing a 
codon-optimized Padua derivative of human coagulation factor IX cDNA 
(CSL222 [formerly AMT-061]) 
ABR 
Annualized bleeding rate 
ADaM 
Analysis Data Model 
ADR 
Adverse drug reaction 
AE 
Adverse event 
AFP 
Alpha-fetoprotein 
ALP 
Alkaline phosphatase 
ALT 
Alanine aminotransferase 
aPTT 
Activated partial thromboplastin time 
AST 
Aspartate aminotransferase 
ATMP 
Advanced therapy medicinal product 
BPI 
Brief Pain Inventory 
CAP 
Controlled Attenuation Parameter 
CDISC 
Clinical Data Interchange Standards Consortium 
cDNA 
Complementary deoxyribonucleic acid 
CHMP 
Committee for Medicinal Products for Human Use 
Cmax 
Maximum concentration 
COVID-19 
Coronavirus Disease 2019 
CRA 
Clinical research associate 
CRO 
Contract Research Organization 
CRP 
C-reactive protein 
CSR 
Clinical Study Report 
DILI 
Drug Induced Liver Injury 
DMC 
Data Monitoring Committee 
eCRF 
Electronic case report form 
ELISA 
Enzyme-linked immunosorbent assay 
EMA 
European Medicines Agency 
EQ-5D-5L 
EuroQol-5 dimensions-5 levels: Refers to both the EQ-5D-5L descriptive 
system and the EQ Visual Analogue Scale (VAS) 
EU 
European Union 
FAS 
Full Analysis Set 
FDA 
Food and Drug Administration 
FIX 
Coagulation factor IX 
GFP 
Green fluorescent protein 
ɣGT 
Gamma-glutamyl transferase 

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gc 
Genome copies 
GCP 
Good Clinical Practice 
GEE 
Generalized estimating equation 
GTWP 
Gene Therapy Working Party 
HAL 
Hemophilia Activities List 
HBsAg 
Hepatitis B surface antigen 
HBV DNA 
Hepatitis B virus deoxyribonucleic acid 
HCV RNA 
Hepatitis C virus ribonucleic acid 
Hem-A-QoL 
Hemophilia specific quality of life index 
hFIX 
Human coagulation factor IX 
HIPAA 
Health Insurance Portability and Accountability Act 
HJHS 
Hemophilia Joint Health Score 
ICH 
International Council for Harmonisation (previously International 
Conference on Harmonisation) 
IEC 
Independent Ethics Committee 
IFNγ 
Interferon gamma 
IgG 
Immunoglobulin G 
IgM 
Immunoglobulin M 
IL-1β 
Interleukin-1beta 
IL-2 
Interleukin-2 
IL-6 
Interleukin-6 
IMP 
Investigational medicinal product 
IND 
Investigational New Drug 
INR 
International Normalized Ratio 
iPAQ 
International Physical Activity Questionnaire 
IRB 
Institutional Review Board 
ISF 
Investigator’s Site File 
IU 
International unit 
IV 
Intravenous 
IWRS 
Interactive Web Response System 
J.A.D.E. 
Joint Tissue Activity and Damage Exam 
MCP-1 
Monocyte chemotactic protein-1 
MedDRA 
Medical Dictionary for Regulatory Activities 
MHRA 
Medicines and Healthcare Products Regulatory Agency (UK) 
MSKUS 
Musculoskeletal Ultrasound 
NAB 
Neutralizing antibody 
NHP 
Non-human primate 
NIAAA 
National Institute of Alcohol Abuse and Alcoholism 
PBGD 
Porphobilinogen deaminase 
PCR 
Polymerase chain reaction 
PP 
Per Protocol 
PRO 
Patient reported outcome 
PROBE 
Patient Reported Outcomes, Burdens, and Experiences 
QoL 
Quality of life 
QP 
Qualified Person 
qPCR 
Quantitative (real-time) polymerase chain reaction 

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RM 
Repeated measures 
SAE 
Serious adverse event 
SAP 
Statistical Analysis Plan 
SARS-CoV-2 
Severe acute respiratory syndrome coronavirus 2 
SD 
Standard deviation 
SDTM 
Study Data Tabulation Model 
SOC 
System Organ Class 
SUSAR 
Suspected unexpected serious adverse reaction 
TEAE 
Treatment-emergent adverse event 
UK 
United Kingdom 
ULN 
Upper limit of normal 
US/USA 
United States of America 
VAS 
Visual Analogue Scale 
WFH 
World Federation of Haemophilia 
WPAI 
Work Productivity and Activity Impairment Questionnaire 

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CLINICAL TRIAL PROTOCOL SYNOPSIS 
Protocol Number:  
CSL222_3001 (formerly 
CT-AMT-061-02) 
Investigational Medicinal Product:  
CSL222 (formerly AMT-061 [AAV5-hFIXco-Padua; etranacogene 
dezaparvovec]) 
Title of the Trial: Phase III, open-label, single-dose, multi-center multinational trial investigating a serotype 5 
adeno-associated viral vector containing the Padua variant of a codon-optimized human factor IX gene 
(AAV5-hFIXco-Padua, AMT-061) administered to adult subjects with severe or moderately severe hemophilia B 
Planned Number of Subjects:  
At least 50 subjects. 
Planned Number of Sites and Site Location(s):  
It is planned to conduct this trial in approximately 50 sites in the United States of America (USA), the European 
Union (EU), and the United Kingdom (UK). 
Coordinating Investigator 
Steven Pipe, MD 
Trial Period (Planned): 
First Subject Screening: Q2 2018 
Last Subject Last Visit: Q2 2025 
Clinical Phase: 
III 
Indication/Trial Population: 
Male subjects with severe or moderately severe hemophilia B. 
Objectives: 
Primary: To demonstrate the non-inferiority of CSL222 (formerly AMT-061 [2 × 1013 gc/kg]) during the 52 weeks 
following establishment of stable factor IX expression (months 6 to 18) post-treatment (CSL222) follow-up 
compared to standard of care continuous routine factor IX prophylaxis during the lead-in phase, as measured by 
the annualized bleeding rate (ABR). 
Secondary: To demonstrate additional efficacy and safety aspects of systemic administration of CSL222. 
Rationale: 
Somatic gene therapy for hemophilia B offers the potential for shift of the disease severity from severe to a moderate 
or mild hemophilic phenotype or complete amelioration through continuous endogenous production of factor IX 
protein after a single administration of adeno-associated viral vector particles. Even a small rise in constantly 
circulating factor IX protein can substantially ameliorate the bleeding phenotype. 
Three subjects have been treated with 2 × 1013 genome copies (gc)/kg CSL222 in the dose confirmation Phase IIb 
trial (CSL222_2001 [formerly CT-AMT-061-01]). At the time the original protocol for CSL222_3001 (formerly 
CT-AMT-061-02; dated 16 Feb 2018) was developed, the initial treatment phase was complete for this study and 
an interim analysis based on a minimum of 6 weeks of post-treatment follow-up data for each subject had been 
performed. The interim analysis data set included a combined 24 weeks of observation. All 3 subjects had been 
diagnosed with severe hemophilia B, with corresponding circulating factor IX activity levels < 1% of normal. 
Following treatment with CSL222, an increased level of factor IX activity was observed in all 3 subjects with mean 
± standard deviation [SD] factor IX activity of 30.6 ± 6.97% (range: 23.9 – 37.8%) at Week 6 and 28.5 ± 6.42% 
(range 20.6 – 37.8%) across visits. Factor IX activity was measured using the activated partial thromboplastin time 
(aPTT) assay performed at a central laboratory. Two out of 3 subjects had previously screen-failed another gene 
therapy study due to pre-existing neutralizing antibodies (NABs) to a different AAV vector. All 3 subjects had 
evidence of pre-existing NAB activity against adeno-associated viral vector serotype 5 (AAV5). No bleeding 
episodes were reported with an ABR of 0; in the year prior to screening, the number of treatment-requiring bleeding 
episodes ranged between 1 and 5. No subjects required any infusions of factor IX replacement therapy post-CSL222 
treatment. No deaths, serious adverse events (SAEs), or treatment-emergent adverse events (TEAEs) resulting in 
early discontinuation from the trial were reported. There were 13 TEAEs reported in 2 subjects, including 2 TEAEs 
assessed as related to study treatment; all TEAEs were mild in severity. One subject experienced a mild, 
asymptomatic and transient increase in liver enzyme levels (specifically elevated aspartate aminotransferase [AST] 

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levels), which resolved without any additional treatment. No T cell response was observed in any of the 3 subjects. 
None of the subjects developed inhibitory antibodies to factor IX. Overall, the dose of 2 × 1013 gc/kg CSL222 was 
shown to be safe and well tolerated and resulted in mean factor IX activity levels approximately 30% of normal 
circulating factor IX 6 weeks after dosing. 
CSL222 is a derivative of CSL220 (formerly AMT-060), which has been studied in the Phase I/II clinical trial in 
male subjects with severe or moderately severe hemophilia B. Both CSL220 and CSL222 consist of an identical 
rAAV5 capsid. While CSL220 contains the coding sequence for “wild-type” hFIX, a 2-nucleotide change has been 
introduced within the hFIX coding sequence in CSL222, resulting in a single amino acid substitution, where 
Arginine is replaced by Leucine at position 338 (R338L) of the mature factor IX protein. The intended change in 
the mature protein represents the hFIX-Padua variant and it is responsible for the observed increased factor IX 
activity per unit of dose achieved with CSL222 as compared to its predecessor CSL220. The isolated modification 
leading to the representation of the hFIX-Padua variant in CSL222 is not expected to influence other established 
safety characteristics of AAV5. 
The results with CSL222 are complemented by robust efficacy and safety data obtained with CSL220 in the 
Phase I/II trial (CSL220_1001 [formerly CT-AMT-060-01]) in 10 subjects with hemophilia B. At the time the 
original protocol for CSL222_3001 was developed, these 10 subjects had been followed for up to 2.5 years after 
treatment. The data demonstrate that subjects achieve clinically relevant and stable factor IX activity levels for up 
to 2.5 years after treatment with CSL220. In addition, the CSL220 treatment remains safe and well-tolerated. 
Alanine aminotransferase (ALT) increase was reported for 3 out of the 10 subjects in the study, however the ALT 
increases did not lead to loss of factor IX activity and no T-cell response was observed in these subjects. There was 
no loss of factor IX activity over time, and there were no immune responses and no development of factor IX 
inhibitors for any of the 10 subjects in the study.  
The purpose of this Phase III trial is to demonstrate the efficacy of CSL222 in terms of ABR, to further describe its 
efficacy in terms of endogenous factor IX activity, and to further describe its safety profile. The efficacy and safety 
results obtained during the Phase IIb study with CSL222 (CSL222_2001), supplemented with the strong efficacy 
and safety results obtained during the Phase I/II trial with CSL220 (CSL220_1001), demonstrate 2 × 1013 gc/kg to 
be the optimal dose for use in this pivotal Phase III trial.  
Investigational Medicinal Product, Dose, and Mode of Administration: 
The investigational medicinal product (IMP) is identified as AAV5-hFIXco-Padua (CSL222; etranacogene 
dezaparvovec). CSL222 is a recombinant AAV5 containing the Padua variant of a codon-optimized human 
factor IX complementary deoxyribonucleic acid (cDNA) under the control of a liver-specific promoter. The 
pharmaceutical form of CSL222 is a solution for intravenous (IV) infusion. 
The single administered dose of CSL222 will be 2 × 1013 gc/kg. 
Reference Therapy: 
The reference therapy is the prophylaxis factor IX replacement therapy used during the lead-in phase, prior to 
treatment with CSL222. 
Trial Design/Methodology: 
This is an open-label, single-dose, multi-center, multinational trial, with a screening period, a lead-in phase, a 
treatment + post-treatment follow-up phase, and a long-term follow-up phase. 
Screening (Visit S) 
At the screening visit (Visit S), subjects are assessed for eligibility. Subjects will be asked to complete the Patient 
Reported Outcome (PRO) questionnaires and the hemophilia joint health score (HJHS) will be assessed. Screening 
assessments will also include medical history, vital signs, physical examination, and blood sampling. A 
FibroScan™ will be performed with liver fibrosis scores collected during the assessment. If possible, steatosis 
(Controlled Attenuation Parameter) scores should also be collected during the assessment. If a site does not have 
access to FibroScan, a Sponsor-preapproved alternative may be performed. At this visit, subjects will receive their 
electronic diary (e-diary) and the Investigator/study nurse will train them in recording of the bleeding episodes and 
use of factor IX replacement therapy. From screening onwards, subjects will record their use of factor IX 
replacement therapy and bleeding episodes in their dedicated e-diary. The period between the screening visit up to 
the start of the lead-in phase (Visit L1) is considered a training period, after which the Investigator/study nurse will 

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review and evaluate any problems with recording of e-diary data with the subject. The e-diary training can be 
repeated at any time during the trial as considered necessary by the Investigator/study nurse. From screening 
onwards, the Investigator or designee will have regular discussions with the subject regarding the importance of a 
healthy liver before and after receiving a liver directed gene therapy, and factors that might impact liver health 
(including acetaminophen and alcohol intake). 
Lead-in phase (Visit L1 to L-Final) 
Eligible subjects will enter the lead-in phase. The length of the lead-in phase is a minimum of 6 months (26 weeks), 
ending at or before Visit D. Subjects will remain in the lead-in phase until a minimum of 6 months of lead-in data 
have been collected and it is confirmed that the subjects still meet all eligibility criteria, with the final visit in this 
phase (Visit L-Final) occurring approximately 4 weeks (6 weeks maximum) prior to the planned date of IMP dose 
administration (Visit D).  
Prior to the start of the lead-in phase (Visit L1), subjects will undergo a wash out period from their usual factor IX 
product/dose. The wash out period will be 3 days for regular-acting factor IX products and 10 days for extended 
half-life factor IX products. At Visit L1, blood samples for assessment of factor IX activity and factor IX protein 
concentration will be taken. 
During the lead-in phase, subjects will record their use of prophylactic factor IX replacement therapy and bleeding 
episodes in their e-diary. e-diary data will be reviewed on a continuous basis by the Investigator/study nurse, with 
alternating monthly clinic visits and follow-up phone calls (in line with the trial schedule and with retraining by 
phone as needed). In addition to the subjects’ reporting of bleeding episodes in the e-diary, the Investigator or 
designee will assess each bleeding episode as soon as possible but at least within 72 hours after it has been reported 
by the subject. In case the information provided in the e-diary is not sufficient to assess the bleeding episode, the 
subject must be called and/or visit the site. At the clinic visits during this lead-in phase (occurring every 2 months), 
blood samples will be taken for assessment of factor IX activity, transaminases, and AAV5 antibodies. Subjects 
will be asked to complete the PRO questionnaires at Visit L3. 
If the informed consent form (ICF) is revised during the lead-in phase with important new information that must 
be shared with the study subjects, the amended ICF will be presented, as required by the Institutional Review Board 
(IRB)/Independent Ethics Committee (IEC), for review and consideration by the subject, and signed re-consent is 
to be obtained prior to IMP dose administration. During Visit L-Final, the subject’s eligibility will be re-evaluated 
based on assessments during the lead-in period and at Visit L-Final. Blood samples will be taken, and the laboratory 
values obtained at this visit will be used to determine eligibility for dosing and continued participation in the trial. 
At this visit, subjects will be asked to complete the PRO questionnaires, HJHS will be assessed, a physical 
examination will be performed, and vital signs will be measured. The baseline abdominal ultrasound should be 
done at Visit L-Final at the latest. Additionally, blood samples for the factor IX recovery assessment will be taken 
before and 30 minutes after (timed from end of infusion) subjects have taken their usual factor IX treatment at this 
visit. 
IMP dose administration (treatment; Visit D) + Post-treatment follow-up phase (Visit F1 to F-Final [Week 1 to 
Week 52/Month 12]) 
At Visit D, pre-IMP dose administration, subject’s eligibility will be confirmed, vital sign measurements will be 
taken, a physical examination will be performed, and blood samples will be taken for assessment of factor IX 
activity, routine laboratory parameters, transaminases, and AAV5 antibodies. 
Once eligibility is confirmed and all baseline assessments have been performed, subjects will receive a single 
infusion of CSL222. After IMP administration (post-IMP), subjects will be monitored at the clinical trial site for 
3 hours or 8 hours (only subjects in Germany) for tolerance to the IMP and detection of potential immediate adverse 
events (AEs). 
Subjects will then be followed for 1 year (52 weeks) in the post-treatment follow-up phase (Visit F1 to F-Final 
[Week 1 to Week 52/Month 12]). Subjects will have weekly visits for the first 12 weeks (Visit F1 to F12 [Week 1 
to 12]), and monthly visits from Month 4 to Month 12 (Visit F13 to F-Final [Month 4 to Month 12/Week 52]). With 
agreement from the Investigator and Sponsor, visits that do not include physical examination and/or PRO 
questionnaires may be performed at the subject’s home by an appropriately qualified and trained nurse. Each home 
nursing visit is expected to be supplemented by a phone call from the Investigator or designee to the subject to 
discuss AEs, concomitant medications, and e-diary compliance. Adjustments to the visit location or schedule may 
be made to accommodate safety concerns and restrictions due to the Coronavirus Disease 2019 (COVID-19) 

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pandemic. In all cases, subjects will be kept informed, via the site staff, as much as possible of changes to the study 
and monitoring plans that could impact them. 
Subjects are permitted to continue their continuous routine factor IX treatment in the first weeks after dosing. 
During the post-treatment follow-up visits, endogenous factor IX activity will be assessed. If the endogenous 
factor IX activity is ≥ 5%, continuous routine factor IX prophylaxis will be discontinued, and further management 
will be based on Investigator’s clinical judgement and subject preference. Continuation or re-initiation of 
continuous routine factor IX prophylaxis may be considered if the endogenous factor IX activity is between 2 and 
5% in at least 2 consecutive laboratory measurements, based on the Investigator’s clinical judgement and subject 
preference. If endogenous factor IX activity is < 2%, continuous routine factor IX prophylaxis must be continued 
or reinstated. Additional on-demand and/or intermittent prophylactic factor IX treatment may be given after 
treatment with CSL222, if considered necessary. 
During the post-treatment follow-up phase, subjects will continue to record their use of factor IX replacement 
therapy and bleeding episodes in the e-diary, following the same principles as during the lead-in phase. Further 
samples will be taken for safety and efficacy laboratory parameters. Subjects will complete the PRO questionnaires 
at Visit F15 (Month 6) and Visit F-Final (Month 12), and joint health (HJHS) will be assessed at Visit F-Final. 
Additionally, an abdominal ultrasound will be performed at Visit F-Final. Use of concomitant medication and 
occurrence of AEs will be continuously monitored. The discussions with the subject on the importance of a healthy 
liver, and factors that might impact liver health (including acetaminophen and alcohol intake), will continue. 
For ALT level increments of at least 2-fold baseline (ie, Visit D, pre-IMP), and/or greater than the upper limit of 
normal (> ULN), by local or central laboratory, the Investigator should contact the Medpace and/or CSL Behring 
Medical Directors to discuss to discuss a clinical management plan on a case-by-case basis, including potential 
re-tests and/or initiation of corticosteroid treatment. In case of AST level increments > ULN, the Investigator should 
contact the Medpace and/or CSL Behring Medical Directors and a similar discussion should take place. 
The first secondary endpoint, endogenous factor IX activity at 6 months after IMP administration, will be assessed 
once the last subject has achieved 6 months after CSL222 treatment. The second secondary endpoint, endogenous 
factor IX activity at 12 months after IMP administration, will be assessed once the last subject has achieved 
12 months after CSL222 treatment. After 52 weeks following stable factor IX expression, all available efficacy and 
safety data collected between screening and 18 months post-treatment will be analyzed and reported in a Clinical 
Study Report (CSR), including (but not limited to), the primary ABR endpoint, and the previously assessed 
secondary endpoints related to factor IX activity at 6 and 12 months. 
Long-term follow-up phase (Visit LTF1 to LTF8 [Month 18 to Month 60]) 
After the post-treatment follow-up phase, subjects will enter a long-term follow-up phase for an additional 4 years 
to assess sustainability of efficacy and long-term safety. During this phase, subjects do not have to record e-diary 
data but are expected to document factor IX usage and bleeding episode information in study-specific paper diaries. 
Subjects are expected to bring their long-term follow-up bleed diaries and long-term follow-up factor IX use diaries 
to every study visit during the long-term follow-up phase, and site staff will collect the new information at each 
visit. In between study visits, subjects should contact the site staff immediately in case of an experienced bleeding 
episode and/or factor IX use in addition to completing the questions/information requested on the paper diaries to 
capture all information. Subjects who are on continuous routine factor IX prophylaxis during the long-term 
follow-up phase of the trial are required to contact the site staff immediately in case of a bleeding episode and/or 
factor IX use different from their routine factor IX prophylaxis, in addition to completing the questions/information 
requested on the paper diaries to capture all information. 
Subjects visit the clinic every half year (6 months) for evaluation of efficacy parameters and safety. Every 6 months 
an abdominal ultrasound will be performed. Every year (12 months), subjects will complete the PRO questionnaires 
and joint health (HJHS) will be assessed. Occurrence of AEs will be continuously monitored, with at least quarterly 
contact between the site staff and subject; proper completion of the study-specific paper diaries and proper reporting 
of factor IX usage and bleeding episodes will also be monitored at these quarterly contacts. Adjustments to the visit 
location or schedule may be made to accommodate safety concerns and restrictions due to the COVID-19 pandemic. 
In all cases, subjects will be kept informed, via the site staff, as much as possible of changes to the study and 
monitoring plans that could impact them. 

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At the end of the trial, all safety and efficacy data from the long-term follow-up will be analyzed and reported in a 
CSR addendum.  
Refer to Figure 1 and Figure 2 for an overview of the study and its design and to Table 1 through Table 4 for an 
overview of the assessments and testing performed throughout these different trial phases. 
Optional Patient Reported Outcomes, Burdens, and Experiences (PROBE) Questionnaire Sub-study 
Subjects who consent to this sub-study will complete the PROBE questionnaire at the same visits as the other PRO 
questionnaires. Adjustments to the visit schedule may be made to accommodate safety concerns and restrictions 
due to the COVID-19 pandemic. 
Optional Musculoskeletal Ultrasound (MSKUS) Sub-study 
Subjects who consent to this optional sub-study will undergo musculoskeletal ultrasounds (MSKUS) at screening 
(Visit S), Visit L-Final, during the post-treatment follow-up at Visits F15 (Month 6) and F-Final 
(Month 12/Week 52), and during the long-term follow-up at Visits LTF2, LTF4, LTF6, and LTF8 (Month 24, 36, 
48, and 60, respectively). Adjustments to the visit schedule may be made to accommodate safety concerns and 
restrictions due to the COVID-19 pandemic. 
Long-term Follow-up Extension Trial (Not Part of This Trial) 
At the end of this trial, subjects will be informed about the option to participate in a separate long-term follow-up 
extension trial (CSL222_3003) to monitor the long-term safety and efficacy of CSL222 from approximately 
5 to 15 years after treatment. 
Trial Assessments: 
Efficacy assessments include the e-diary for recording of bleeding episodes and factor IX use, several laboratory 
parameters (including factor IX protein and activity levels), assessment of joint health, and the PRO questionnaires 
on general and disease specific quality of life (QoL). The PROBE questionnaire and MSKUS will be assessed for 
subjects participating in these sub-studies. 
Safety is assessed by AEs, physical examination, and laboratory parameters. 
Inclusion and Exclusion Criteria: 
Inclusion Criteria: 
1. Male 
2. Age ≥ 18 years 
3. Subjects with congenital hemophilia B with known severe or moderately severe factor IX deficiency (≤ 2% of 
normal circulating factor IX) for which the subject is on continuous routine factor IX prophylaxis* 
4. > 150 previous exposure days of treatment with factor IX protein 
5. Have been on stable prophylaxis for at least 2 months prior to screening 
6. Have demonstrated capability to independently, accurately and in a timely manner complete the diary during 
the lead-in phase as judged by the Investigator 
7. Acceptance to use a condom during sexual intercourse in the period from IMP administration until AAV5 has 
been cleared from semen, as evidenced by the central laboratory from negative analysis results for at least 
3 consecutively collected semen samples (this criterion is applicable also for subjects who are surgically 
sterilized) 
8. Able to provide informed consent following receipt of verbal and written information about the trial. 
* Continuous routine prophylaxis is defined as the intent of treating with an a priori defined frequency of infusions 
(eg, twice weekly, once every 2 weeks, etc) as documented in the medical records. 

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Exclusion Criteria: 
1. History of factor IX inhibitors 
2. Positive factor IX inhibitor test at screening and Visit L-Final (based on local laboratory results) 
3. Screening and Visit L-Final laboratory values (based on central laboratory results): 
a. 
ALT > 2 times ULN 
b. AST > 2 times ULN 
c. 
Total bilirubin > 2 times ULN (except if this is caused by Gilbert disease) 
d. Alkaline phosphatase (ALP) > 2 times ULN 
e. 
Creatinine > 2 times ULN 
4. Positive human immunodeficiency virus (HIV) serological test at screening and Visit L-Final, not controlled 
with anti-viral therapy as shown by CD4+ counts ≤ 200/μL (based on central laboratory results) 
5. Hepatitis B or C infection with the following criteria present at screening: 
a. 
Currently receiving antiviral therapy for this/these infection(s) 
and/or 
b. Positive for any of the following (based on central laboratory results): 
i. Hepatitis B surface antigen (HBsAg), except if in the opinion of the Investigator this is due to 
a previous Hepatitis B vaccination rather than active Hepatitis B infection 
ii. Hepatitis B virus deoxyribonucleic acid (HBV DNA) 
iii. Hepatitis C virus ribonucleic acid (HCV RNA) 
6. Known coagulation disorder other than hemophilia B 
7. Thrombocytopenia, defined as a platelet count below 50 × 109/L, at screening and Visit L-Final (based on 
central laboratory results) 
8. Known severe infection or any other significant concurrent, uncontrolled medical condition including, but not 
limited to, renal, hepatic, cardiovascular, hematological, gastrointestinal, endocrine, pulmonary, neurological, 
cerebral or psychiatric disease, alcoholism, drug dependency or any other psychological disorder evaluated by 
the Investigator to interfere with adherence to the protocol procedures or with the degree of tolerance to the 
IMP 
9. Known significant medical condition that may significantly impact the intended transduction of the vector 
and/or expression and activity of the protein, including but not limited to: 
a. 
Disseminated intravascular coagulation 
b. Accelerated fibrinolysis 
c. 
Advanced liver fibrosis (suggestive of or equal to METAVIR Stage 3 disease; eg, a FibroScan™ score of 
≥ 9 kPa is considered equivalent) 
10. Known history of an allergic reaction or anaphylaxis to factor IX products 
11. Known history of allergy to corticosteroids 
12. Known uncontrolled allergic conditions or allergy/hypersensitivity to any component of the IMP excipients 
13. Known medical condition that would require chronic administration of steroids 
14. Previous gene therapy treatment 
15. Receipt of an experimental agent within 60 days prior to screening 

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16. Current participation or anticipated participation within 1 year after IMP administration in this trial in any 
other interventional clinical trial involving drugs or devices. 
Planned Duration of Subject Involvement in the Trial: 
• 
Planned duration of screening/enrolment period: approximately 4 weeks 
• 
Planned duration of lead-in phase: at least 26 weeks (6 months) 
• 
Planned duration of treatment: 1 day (single dose) 
• 
Planned duration of follow-up: 52 weeks, plus long-term safety follow-up until Month 60 
Endpoints and Statistical Analysis:  
Primary efficacy endpoints 
- 
ABR comparison between CSL222 and prophylaxis for non-inferiority between the lead-in phase and the 
52 weeks following stable factor IX expression (months 6-18 post-treatment) 
Secondary efficacy endpoints 
- 
Endogenous factor IX activity at 6 months after CSL222 dosing 
- 
Endogenous factor IX activity at 12 months after CSL222 dosing 
- 
Endogenous factor IX activity at 18 months after CSL222 dosing 
- 
Annualized consumption of factor IX replacement therapy during the 52 weeks following stable factor IX 
expression (months 6-18 post-treatment), excluding factor IX replacement for invasive procedures, 
compared to the lead-in phase 
- 
Annualized infusion rate of factor IX replacement therapy during the 52 weeks following stable factor IX 
expression (months 6-18 post-treatment), excluding factor IX replacement for invasive procedures, 
compared to the lead-in phase 
- 
Proportion of subjects remaining free of previous continuous routine prophylaxis during the 52 weeks 
following stable factor IX expression (months 6-18 post-treatment) 
- 
Comparison of the percentage of subjects with trough factor IX activity < 12% of normal between the 
lead-in phase and after treatment with CSL222 over the 52 weeks following stable factor IX expression 
(months 6-18 post-treatment) 
- 
ABR comparison between CSL222 and prophylaxis for superiority between the lead-in phase and the 
52 weeks following stable factor IX expression (months 6-18 post-treatment) 
- 
Rate of spontaneous bleeding events during the 52 weeks following stable factor IX expression 
(months 6-18 post-treatment) compared to the lead-in phase 
- 
Rate of joint bleeding events during the 52 weeks following stable factor IX expression (months 6-18 
post-treatment) compared to the lead-in phase 
- 
Estimated ABR – during the 52 weeks following stable factor IX expression (months 6-18 post-treatment) 
– as a function of pre-IMP anti-AAV5 antibody titers using the luciferase-based NAB assay (as a 
“correlation” analysis) 
- 
Correlation of factor IX activity levels during the 52 weeks following stable factor IX expression 
(months 6-18 post-treatment) with pre-IMP anti-AAV5 antibody titers using the luciferase-based NAB 
assay 
- 
Occurrence of (and resolution of) new target joints during the 52 weeks following stable factor IX 
expression (months 6-18 post-treatment) and resolution of pre-existing target joints following CSL222 
dosing 
- 
Proportion of subjects with zero bleeds during the 52 weeks following stable factor IX expression 
(months 6-18 post-treatment) 
- 
PRO questionnaire scores from the international Physical Activity Questionnaire (iPAQ; total physical 
activity score) during the 12 months following CSL222 dosing compared with the lead-in phase 
- 
PRO questionnaire scores from the EuroQol-5 dimensions-5 levels (EQ-5D-5L) visual analogue scale 
(VAS) score during the 12 months following CSL222 dosing compared with the lead-in phase 

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Exploratory efficacy endpoints 
- 
Factor IX protein levels during the 18 months following CSL222 dosing 
- 
HJHS scores during the lead-in phase (prophylaxis) and during the 12 months following CSL222 dosing 
- 
Other PRO questionnaires: Work Productivity and Activity Impairment Questionnaire (WPAI), Brief Pain 
Inventory (BPI), hemophilia activities list (HAL), and Hemophilia Quality of Life Questionnaire for 
Adults (Hem-A-QoL) questionnaire scores during the lead-in phase (prophylaxis) and during the 
12 months following CSL222 dosing 
- 
EQ-5D-5L Index scores during the lead-in phase (prophylaxis) and during the 12 months following 
CSL222 dosing 
- 
Estimated ABR as a function of mean factor IX activity (as a “correlation” analysis) over the 18 months 
post-CSL222 treatment follow-up 
- 
Rate of traumatic bleeding events during the 52 weeks following stable factor IX expression (months 6-18 
post-treatment) compared to the lead-in phase 
- 
Subgroup analyses will be carried out for the following endpoints: 
- 
Endogenous factor IX activity at Month 18 
- 
Annualized consumption of factor IX replacement therapy during the 52 weeks following stable 
factor IX expression (months 6-18 post-treatment), excluding replacement for invasive procedures, 
compared to the lead-in phase 
- 
Annualized infusion rate of factor IX replacement therapy during the 52 weeks following stable 
factor IX expression (months 6-18 post-treatment), excluding replacement for invasive procedures, 
compared to the lead-in phase 
- 
ABR comparison between CSL222 during the 52 weeks following stable factor IX expression 
(months 6-18 post-treatment) and factor IX prophylaxis (during the lead-in phase) 
- 
Comparison of the percentage of subjects with trough factor IX activity < 12% of normal between the 
lead-in phase and after treatment with CSL222 during the 52 weeks following stable factor IX 
expression (months 6-18 post-treatment) 
- 
Proportion of subjects remaining free of previous prescribed continuous routine prophylaxis during 
the 52 weeks following stable factor IX expression (months 6-18 post-treatment) 
All efficacy endpoints will be analyzed as exploratory endpoints as part of the CSR addendum written at the end 
of the trial: 
- 
Endogenous factor IX activity at 2, 3, 4, and 5 years after CSL222 dosing 
- 
ABR comparison between CSL222 and prophylaxis for non-inferiority between the 2-year, 3-year, 4-year, 
and 5-year post-treatment (CSL222) follow-up and the lead-in phase 
- 
Annualized consumption of factor IX replacement therapy during the 2-year, 3-year, 4-year, and 5-year 
post-treatment follow-up, excluding factor IX replacement for invasive procedures, compared to the 
lead-in phase 
- 
Annualized infusion rate of factor IX replacement therapy during the 2-year, 3-year, 4-year, and 5-year 
post-treatment follow-up, excluding factor IX replacement for invasive procedures, compared to the 
lead-in phase 
- 
Proportion of subjects remaining free of previous continuous routine prophylaxis during the 2-year, 3-year, 
4-year, and 5-year post-treatment follow-up 
- 
Comparison of the percentage of subjects with trough factor IX activity < 12% of normal between the 
lead-in phase and after treatment with CSL222 at 2, 3, 4, and 5 years after CSL222 dosing 

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- 
ABR comparison between CSL222 and prophylaxis for superiority between the lead-in phase and the 
2-year, 3-year, 4-year, and 5-year post-treatment (CSL222) follow-up 
- 
Rate of spontaneous bleeding events during the 2-year, 3-year, 4-year, and 5-year post-treatment (CSL222) 
follow-up compared to the lead-in phase 
- 
Rate of joint bleeding events during the 2-year, 3-year, 4-year, and 5-year post-treatment (CSL222) 
post-treatment follow-up compared to the lead-in phase 
- 
Estimated ABR – at 2 years, 3 years, 4 years, and 5 years post-CSL222 treatment – as a function of 
pre-IMP anti-AAV5 antibody titers using the luciferase-based NAB assay (as a “correlation” analysis) 
- 
Correlation of factor IX activity levels at 2 years, 3 years, 4 years, and 5 years post-CSL222 treatment 
with pre-IMP anti-AAV5 antibody titers using the luciferase-based NAB assay 
- 
Occurrence and resolution of target joints during the 2 years, 3 years, 4 years, and 5 years following 
CSL222 dosing 
- 
Proportion of subjects with zero bleeds in the 2 years, 3 years, 4 years, and 5 years post-treatment 
(CSL222) follow-up 
- 
PRO questionnaire scores from the iPAQ at 2 years, 3 years, 4 years, and 5 years post-CSL222 treatment 
compared to the lead-in phase 
- 
PRO questionnaire scores from the EQ-5D-5L at 2 years, 3 years, 4 years, and 5 years post-CSL222 
treatment compared to the lead-in phase 
- 
Factor IX protein levels during the 2 years, 3 years, 4 years, and 5 years following CSL222 dosing 
- 
HJHS scores during the lead-in phase (prophylaxis) and during the 2 years, 3 years, 4 years, and 5 years 
following CSL222 dosing 
- 
Other PRO questionnaires: WPAI, BPI, HAL, and Hem-A-QoL questionnaires during the lead-in phase 
(prophylaxis) and during the 2 years, 3 years, 4 years, and 5 years following CSL222 dosing 
- 
Estimated ABRs over time as a function of mean factor IX activity (as a “correlation” analysis) over the 
2 years, 3 years, 4 years, and 5 years post-CSL222 treatment follow-up 
- 
Rate of traumatic bleeding events during the 2 years, 3 years, 4 years, and 5 years post-treatment follow-up 
compared to the lead-in phase 
Sub-study endpoints 
- 
PROBE summary scores and individual item responses. 
- 
MSKUS sub-study endpoints 
- 
Joint Tissue Activity and Damage Exam (J.A.D.E.) scores 
Secondary safety endpoints 
- 
Adverse events (AEs) 
- 
Changes in abdominal ultrasound 
- 
Anti-AAV5 antibodies (total [IgM and IgG], NABs) 
- 
AAV5 capsid-specific T cells 
- 
Anti-factor IX antibodies 
- 
Factor IX inhibitors and recovery 
- 
Hematology and serum chemistry parameters 
- 
ALT/AST levels, and corticosteroid use for ALT/AST increases 
- 
Vector DNA in blood and semen 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 22 of 150 
- 
Inflammatory markers: IL-1β, IL-2, IL-6, IFNγ, MCP-1 
- 
Alpha-fetoprotein (AFP) 
Analysis Populations 
The Full Analysis Set (FAS) will include all subjects who are enrolled, entered the lead-in phase, were dosed with 
CSL222, and provide at least one efficacy endpoint assessment subsequent to CSL222 dosing. The FAS population 
will be the primary population for all efficacy statistical analyses. 
The PP population will include all subjects from the FAS population who adhere to a stable and adequate 
prophylaxis use during the lead-in phase, who complete at least 18 months of efficacy assessments (52 weeks after 
achieving stable factor IX expression) for the 18-month (data cut) analysis, who complete at least a full year of 
efficacy assessments for the 12-month (data cut) analysis, or who complete at least 6 months of efficacy assessments 
for the 6-month (data cut) analysis, and who have no major protocol deviations that impact the interpretation of 
efficacy. The PP population will be used for sensitivity analyses. 
The lead-in safety population will consist of all subjects who receive lead-in treatment (ie, who are enrolled into 
the lead-in period). The post-treatment safety population will consist of all subjects who receive CSL222, 
irrespective of any protocol deviations. The safety population will consist of all subjects who are in either the 
lead-in safety population or the post-treatment safety population.  
Sample Size 
The study sample size is constrained by the non-inferiority analysis of the primary endpoint, ABR. Via simulation 
of ABR under a negative binomial distribution with a yearly rate of 2.4 events for lead-in and 1.9 for post-treatment, 
with a Pearson correlation of 0.05 for the number of events between the 2 periods, and with a common negative 
binomial dispersion parameter of 1.5, a sample size of N = 50 will demonstrate non-inferiority with a 
non-inferiority margin of 1.8 and a power of 82.0%. Therefore, the study should consist of at least 50 analyzable 
subjects. 
Statistical Methods 
Primary efficacy analyses 
The primary aim of the trial is to demonstrate the non-inferiority of CSL222 (2 × 1013 gc/kg) during the 52 weeks 
following establishment of stable factor IX expression (months 6 to 18) post-treatment (CSL222) follow-up 
compared to standard of care continuous routine factor IX prophylaxis during the lead-in phase, as measured by 
the ABR. 
Single treatment with CSL222 will be claimed to be non-inferior to factor IX prophylaxis treatment when the upper 
limit of the one-sided 97.5% confidence interval of the rate ratio in ABR between CSL222 (post-treatment) and 
factor IX prophylaxis (lead-in) is less than 1.8. 
ABR will be determined for the lead-in period and post-treatment period (for the 52 weeks following stable 
factor IX expression [months 6-18 post-treatment with CSL222]). Analysis of the number of reported bleeding 
events will be performed using a repeated measures (RM) generalized estimating equation (GEE) negative binomial 
regression model accounting for the paired design of the trial with an offset parameter to account for the differential 
collection periods. The estimated rate ratio, one-sided 97.5% Wald confidence interval, and corresponding p-value 
will be determined. The upper limit of the resultant confidence interval of the rate ratio will be compared to the 
non-inferiority margin of 1.8. If the upper limit is less than 1.8, then non-inferiority will be declared. 
The primary efficacy analysis of ABR for the non-inferiority assessment will be completed using the FAS. 
Order of testing of primary and secondary endpoints 
Formal statistical testing of the efficacy endpoints will be performed using the closed testing principle (for Type I 
error control for multiple testing). Due to the closed testing principle, no correction for multiplicity is necessary. 
All endpoints will be tested for superiority at a one-sided alpha level of 0.025 (except as otherwise noted). 
Superiority and non-inferiority testing will be accomplished using the FAS population. Fixed sequential testing will 
be performed using a hierarchical approach and will be continued until a non-significant result is obtained (except 
as otherwise noted). The primary and secondary endpoints will be analyzed in the following order.  

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 23 of 150 
1. ABR comparison between CSL222 and prophylaxis for non-inferiority between the lead-in phase and the 
52 weeks following stable factor IX expression (months 6-18 post-treatment; primary efficacy endpoint) 
2. Endogenous factor IX activity at 6 months after CSL222 (first secondary efficacy endpoint) 
3. Endogenous factor IX activity at 12 months after CSL222 (second secondary efficacy endpoint) 
4. Endogenous factor IX activity at 18 months after CSL222 (third secondary efficacy endpoint) 
5. Annualized consumption of factor IX replacement therapy during the 52 weeks following stable factor IX 
expression (months 6-18 post-treatment), excluding factor IX replacement for invasive procedures, 
compared to the lead-in phase (secondary efficacy endpoint) 
6. Annualized infusion rate of factor IX replacement therapy during the 52 weeks following stable factor IX 
expression (months 6-18 post-treatment), excluding factor IX replacement for invasive procedures, 
compared to the lead-in phase (secondary efficacy endpoint) 
7. Comparison of the percentage of subjects with trough factor IX activity < 12% of normal between the 
lead-in phase and after treatment with CSL222 over the 52 weeks following stable factor IX expression 
(months 6-18 post-treatment; secondary efficacy endpoint) 
8. ABR comparison between CSL222 and prophylaxis for superiority between the lead-in and the 52 weeks 
following stable factor IX expression (months 6-18 post-treatment); secondary efficacy endpoint) 
9. Rate of spontaneous bleeding events during the 52 weeks following stable factor IX expression 
(months 6-18 post-treatment) compared to the lead-in phase (secondary efficacy endpoint) 
10. Rate of joint bleeding events during the 52 weeks following stable factor IX expression (months 6-18 
post-treatment) compared to the lead-in phase (secondary efficacy endpoint) 
11. PRO questionnaire scores from the iPAQ (total physical activity score) during the 12 months following 
CSL222 dosing compared with the lead-in phase (secondary efficacy endpoint) 
12. PRO questionnaire scores from the EQ-5D-5L VAS score during the 12 months following CSL222 dosing 
compared with the lead-in phase (secondary efficacy endpoint) 
Exploratory analysis 
All exploratory endpoints will be presented using descriptive statistics, where applicable. No formal statistical 
testing will be performed. Analysis will be based on the FAS and the PP population and will be described in the 
Statistical Analysis Plan. 
Safety analyses 
Adverse events will be coded using the most recent version of the Medical Dictionary for Regulatory Activities 
(MedDRA). Total treatment-emergent AEs (TEAEs), and broken down by relationship, severity, seriousness, will 
be presented descriptively by system organ class and preferred term, presenting number and percentage of subjects 
and number of events. 
All other safety data will be presented using graphical displays, descriptive statistics (including change from 
baseline, if applicable), and/or individual data listings. 
The number of days until vector DNA can no longer be detected in blood and semen will be tabulated. The number 
of days is calculated using the date of collection of the first of 3 consecutive sample negative for vector DNA for 
each matrix. 
All safety analyses will be based on the safety population. 
Analyses will be based on central laboratory measurements if results are available from both local and central 
laboratories. 
 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
 
 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 24 of 150 
Study Design Schema 
Figure 1 
Study Overview 
 
IMP: Investigational Medicinal Product. 
 
Figure 2 
Study Design 
 
IMP: Investigational Medicinal Product. 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
 
 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 25 of 150 
Trial Schedules 
Table 1 
Schedule of Events for Efficacy and Safety Evaluation, for Screening (Visit S), Lead-in (Visit L1 to L-Final) and Treatment (Visit D) + 
Post-Treatment Follow-up (Visit F1 to F-Final) 
Trial Period a 
Screening 
Lead-in b, c, d 
IMP Dose 
Administration d 
Post-treatment Follow-up d, e, f 
Additional 
Visits g 
Day / Week / Month 
Visit S h 
Visit L1 
(L-W0)i 
Visit L2 to 
LXj 
(every 
2 months, 
starting at 
L-M2) 
Visit  
L-Final 
Visit D 
pre-IMP 
Visit D 
0h 
Visit D 
post-IMP 
3h k 
Visit D 
post-IMP 
8h l  
Visit F1 to 
F12 
(every 
week 
W1 to 
W12) 
Visit F13 
to F20 
(every 
month 
M4 to 
M11) 
Visit 
F-Final 
(M12/ 
W52) 
 
Visit window (days) 
- 28 
0 
± 14 
j 
0 
0 
± 15 
minutes 
± 15 
minutes 
± 2 
± 5 
± 5 
 
Informed consent 
x 
 
 
 
 
 
 
 
 
 
 
 
Inclusion/exclusion 
criteria 
x 
 
 
x 
x m 
 
 
 
 
 
 
 
Medical history  
x 
 
 
 
 
 
 
 
 
 
 
 
Administration of 
IMP 
 
 
 
 
 
x 
 
 
 
 
 
 
Hand-out of subject 
treatment card n 
 
 
 
 
 
 
x 
x 
 
 
 
 
Concomitant 
medication 
Continuous 
(x) g 
Vital signs (blood 
pressure, pulse, body 
temperature) 
x 
 
 
x 
x 
 
x 
x 
x 
x 
x 
(x) g 
Physical examination 
x 
 
 
x 
x 
 
 
 
x: Visit F1, 
F2, F4, F6, 
F12 
(W1, 2, 4, 
6, 12) 
x: Visit 
F13, F15, 
F17, F19 
(M4, 6, 8, 
10) 
x 
(x) g 
Height 
x 
 
 
 
 
 
 
 
 
 
 
 
Body weight 
x 
 
 
x 
 
 
 
 
 
 
 
(x) g 
FibroScan™ o 
x 
 
 
 
 
 
 
 
 
 
 
 
Blood and semen 
sampling (Table 2)  
x 
x 
x 
x 
x 
 
x 
x 
x 
x 
x 
(x) g 
Subject provided 
e-diary device and 
e-diary instruction p 
x 
 
 
 
 
 
 
 
 
 
 
 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
 
 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 26 of 150 
Trial Period a 
Screening 
Lead-in b, c, d 
IMP Dose 
Administration d 
Post-treatment Follow-up d, e, f 
Additional 
Visits g 
Day / Week / Month 
Visit S h 
Visit L1 
(L-W0)i 
Visit L2 to 
LXj 
(every 
2 months, 
starting at 
L-M2) 
Visit  
L-Final 
Visit D 
pre-IMP 
Visit D 
0h 
Visit D 
post-IMP 
3h k 
Visit D 
post-IMP 
8h l  
Visit F1 to 
F12 
(every 
week 
W1 to 
W12) 
Visit F13 
to F20 
(every 
month 
M4 to 
M11) 
Visit 
F-Final 
(M12/ 
W52) 
 
Visit window (days) 
- 28 
0 
± 14 
j 
0 
0 
± 15 
minutes 
± 15 
minutes 
± 2 
± 5 
± 5 
 
Recording of e-diary 
data by subject 
(bleeding episodes, 
factor IX 
replacement therapy) 
Continuous 
 
Review of e-diary 
data by Investigator/ 
study nurse 
Continuous 
(x) g 
Collection of e-diary 
device 
 
 
 
 
 
 
 
 
 
 
x 
 
Subject provided with 
paper diaries and 
paper diary instruction 
for Long-term 
Follow-up Phase 
 
 
 
 
 
 
 
 
 
 
x 
 
Assessment of 
bleeding episode(s) 
by Investigator q 
Continuous 
(x) g 
Liver health 
discussion (including 
acetaminophen and 
alcohol intake) r 
Continuous 
 
Abdominal 
ultrasound s 
 
 
 
x 
 
 
 
 
 
 
x 
 
EuroQol EQ-5D-5L t 
x 
 
x: Visit L3 
x 
 
 
 
 
 
x: Visit 
F15 (M6) 
x 
 
iPAQ t 
x 
 
x: Visit L3 
x 
 
 
 
 
 
x: Visit 
F15 (M6) 
x 
 
WPAI t 
x 
 
x: Visit L3 
x 
 
 
 
 
 
x: Visit 
F15 (M6) 
x 
 
BPI t 
x 
 
x: Visit L3 
x 
 
 
 
 
 
x: Visit 
F15 (M6) 
x 
 
HAL t 
x 
 
x: Visit L3 
x 
 
 
 
 
 
x: Visit 
F15 (M6) 
x 
 
Hem-A-QoL t 
x 
 
x: Visit L3 
x 
 
 
 
 
 
x: Visit 
F15 (M6) 
x 
 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
 
 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 27 of 150 
Trial Period a 
Screening 
Lead-in b, c, d 
IMP Dose 
Administration d 
Post-treatment Follow-up d, e, f 
Additional 
Visits g 
Day / Week / Month 
Visit S h 
Visit L1 
(L-W0)i 
Visit L2 to 
LXj 
(every 
2 months, 
starting at 
L-M2) 
Visit  
L-Final 
Visit D 
pre-IMP 
Visit D 
0h 
Visit D 
post-IMP 
3h k 
Visit D 
post-IMP 
8h l  
Visit F1 to 
F12 
(every 
week 
W1 to 
W12) 
Visit F13 
to F20 
(every 
month 
M4 to 
M11) 
Visit 
F-Final 
(M12/ 
W52) 
 
Visit window (days) 
- 28 
0 
± 14 
j 
0 
0 
± 15 
minutes 
± 15 
minutes 
± 2 
± 5 
± 5 
 
HJHS 
x 
 
 
x 
 
 
 
 
 
 
x 
 
PROBE (optional) t, u 
x 
 
x: Visit L3 
x 
 
 
 
 
 
x: Visit 
F15 (M6) 
x 
 
Musculoskeletal 
ultrasound  
(optional) v  
x 
 
 
x 
 
 
 
 
 
x: Visit 
F15 (M6) 
x 
 
Adverse events 
Continuous 
(x) g 
BPI: Brief Pain Inventory; D: dosing; h: hour; HAL: Hemophilia activities list; Hem-A-QoL: hemophilia specific quality of life index; HJHS: Hemophilia Joint Health Score; 
IMP: investigational medicinal product; iPAQ: international Physical Activity Questionnaire; L-M: lead-in month; L-W: lead-in week; M: month; PROBE: Patient Reported Outcomes, 
Burdens, and Experiences; QoL: Quality of Life; W: week; WPAI: Work Productivity and Activity Impairment Questionnaire. 
a. 
This table shows events for screening, lead-in, and treatment + post-treatment follow-up. Refer to Table 3 for events during the long-term follow-up. 
b. 
Each visit in the lead-in phase is scheduled in relation to the date of L1 (L-W0), not in relation to the date of its previous visit. 
c. 
The lead-in phase will be a minimum of 6 months, ending at or before Visit D. Visits will occur every 2 months and between visits, there will be a follow-up telephone call for e-diary 
review (alternating months). 
d. 
For subjects on continuous routine prophylactic factor IX replacement therapy, these visits should take place on the day that routine prophylactic factor IX replacement treatment is 
planned to be administered. At these visits, blood sampling will take place prior to administration of prophylactic factor IX replacement therapy. If a subject uses additional on-demand 
factor IX replacement treatment, his upcoming study visit may need to be re-scheduled (to the extent the visit window allows) so that the visit takes place at the time the subject resumes 
his continuous routine prophylaxis schedule. For subjects only using on-demand factor IX replacement therapy (only applicable after CSL222 administration), his upcoming study visit 
may need to be re-scheduled (to the extent the visit window allows) so that the visit does not take place within 5 half-lives of exogenous factor IX product use. In case the 5 half-lives 
washout extends beyond the protocol-allowed visit window, the Medpace and/or CSL Behring Medical Directors are to be contacted to discuss how to proceed. 
e. 
Each visit in the post-treatment follow-up is scheduled in relation to the date of IMP dose administration (Visit D), not in relation to the date of its previous visit. 
f. 
With agreement from the Investigator and Sponsor during the Post-Treatment Follow-Up period (from Visit D up until Week 52), visits that do not include physical examination and/or 
PRO questionnaires may be performed at the subject’s home by an appropriately qualified and trained nurse. Each home nursing visit is expected to be supplemented by a phone call 
from the Investigator or designee to the subject to discuss AEs, concomitant medications, and e-diary compliance. 
g. 
An additional visit can be performed at any time during the study (lead-in or follow-up phases) for the purpose of conducting one or more procedures listed in the column “Additional 
Visits”, as per the preference of the Investigator. Hence, “(x)” refers to a procedure that can be performed, if judged relevant by the Investigator. 
h. 
The approximately 4-week period between the screening visit (Visit S) and the start of the lead-in phase (Visit L1) is considered a training period, after which the Investigator/study 
nurse will review and evaluate any problems with recording of e-diary data with the subject. With prior approval from the Sponsor, screening procedures can occur during the duration 
of the screening period. 
i. 
Prior to the Visit L1, subjects will undergo a wash out period from their usual factor IX product/dose. The wash out period will be 3 days for regular-acting factor IX products and 
10 days for extended half-life factor IX products. 
j. 
Visit window for Visit L-Final is – 28 days (± 7 days) from Visit D. The time period between Visit LX and Visit L-Final can be less than 2 months as long as the total lead-in period is a 
minimum of 26 weeks. 
k. 
Applicable to all subjects excluding those in Germany. 
l. 
Applicable only to subjects in Germany.  

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
 
 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 28 of 150 
m. Laboratory assessments from Visit L-Final will be used for inclusion/exclusion criteria at Visit D. 
n. 
When all assessments at 3 hours post-IMP administration are performed, the subject treatment card will be handed out and the subject may leave the clinic. If a subject is traveling to a 
different site for Visit D, this card should be handed out at the L-Final visit and the subject should be instructed to bring it with him to Visit D. 
o. 
Liver fibrosis scores will be collected during the FibroScan assessment. If possible, steatosis (Controlled Attenuation Parameter [CAP]) scores should also be collected. If a site does not 
have access to FibroScan, a Sponsor-preapproved alternative may be performed. The FibroScan should preferably be done at the screening visit or at an alternative time point, however 
at L-Final at the latest. If a FibroScan assessment has been performed within the year prior to screening for which CAP scores are available or if a liver biopsy has been performed 
within the 2 years prior to the screening visit and fibrosis grade was documented, a FibroScan is not necessary. 
p. 
Instruction can be repeated at any visit as deemed necessary by the Investigator or study nurse. 
q. 
The Investigator or designee will assess each bleeding episode as soon as possible, but at least within 72 hours after it has been reported by the subject. 
r. 
From screening onwards, the Investigator or designee will have regular discussions with the subject regarding the importance of a healthy liver before and after receiving a liver directed 
gene therapy, and factors that might impact liver health (including acetaminophen and alcohol intake). It is recommended that acetaminophen total daily dose per subject be limited to 
≤ 2 g/day. It is also recommended that subjects on the study should not consume > 20 g of alcohol per day. While it is recommended that the daily alcohol limit in grams be adhered to 
most strictly during the first 12 weeks post-IMP, the importance of abstaining from binge-drinking at any point post IMP administration should be reinforced at every visit. 
s. 
The baseline abdominal ultrasound should be done at L-Final at the latest. For those subjects where Visit F-Final (Month 12) is impacted by COVID-19, abdominal ultrasounds may be 
conducted within the following window: up to - 1 month prior to the target visit and up to + 1 month after the target visit. Adjustments to the visit timing within this window are to be 
documented. 
t. 
It is recommended that the patient reported outcome (PRO) questionnaires (EQ-5D-5L/iPAQ/WPAI/BPI/HAL/Hem-A-QoL[/PROBE]) are completed by the subject before he is seen by 
the Investigator and/or study nurse for interview and before other (trial specific) assessments are performed if possible, as well as before the administration of IMP, in order for the 
answers not to be influenced by the information given by the physician, by the administration of IMP, or by early side-effects of the IMP or (trial related) assessments. During the 
screening visit, the PRO questionnaires are recommended to be completed after ICF signature, but before other (trial-specific) assessments are performed. At each visit, the 
questionnaires are to be completed in the same order every time, following the order presented in the protocol. The questionnaires are to be completed under site supervision at the site. 
For those subjects where the Visit F15 and Visit F-Final are impacted by COVID-19, the questionnaires may be conducted at the site within the following window: up to – 1 month 
prior to the target visit, up to + 2 months after the target visit, and at least 4 months after the last assessment. Adjustments to the visit timing within this window are to be documented. 
u. 
Applicable only for subjects participating in the optional PROBE questionnaire sub-study. For those subjects where the Visit F15 and Visit F-Final are impacted by COVID-19, the 
PROBE questionnaire may be conducted at the site within the following window: up to – 1 month prior to the target visit, up to + 2 months after the target visit, and at least 4 months 
after the last assessment. Adjustments to the visit timing within this window are to be documented. 
v. 
Applicable only for subjects participating in the optional musculoskeletal ultrasound (MSKUS) sub-study. If it is not possible to obtain the MSKUS at screening (Visit S), it is allowed 
to obtain this first MSKUS at a later time point (preferably as soon as possible thereafter during one of the lead-in visits). For those subjects where the Visit F15 and Visit F-Final are 
impacted by COVID-19, scans may be conducted within the following window: up to - 1 month prior to the target visit, up to + 2 months after the target visit, and at least 4 months after 
the last MSKUS. Adjustments to the visit timing within this window are to be documented. 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
 
 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 29 of 150 
Table 2 
Schedule of Events for Laboratory Parameters, for Screening (Visit S), Lead-in (Visit L1 to L-Final) and Treatment + Post-Treatment 
Follow-up (Visit F1 to F-Final) 
Trial Period a 
Screening 
Lead-in b, c, d 
IMP Dose 
Administration d 
Post-treatment Follow-up d, e 
Additional 
Visits f 
Day / Week / 
Month 
Visit S 
Visit L1 
(L-W0)g 
Visit L2 
to LX 
(every 2 
months, 
starting 
at L-M2) 
Visit  
L-Final 
Visit D 
pre-IMP 
Visit D 
0h 
Visit D 
post-IMP 
3h i 
Visit D 
post-IMP 
8h j 
Visit F1 to 
F12 
(every week 
W1 to W12) 
Visit F13 
to F20 
(every 
month 
M4 to 
M11) 
Visit 
F-Final 
(M12/ 
W52) 
 
Visit window 
(days) 
- 28 
0 
± 14 
h 
0 
0 
± 15 
minutes 
± 15 
minutes 
± 2 
± 5 
± 5 
 
Local Laboratory 
 
 
 
 
 
 
 
 
 
 
 
 
Factor IX: one-stage 
aPTT for factor IX 
activity for local 
monitoring  
x 
x 
x 
x 
x 
 
 
 
x 
x 
x 
(x) f 
Factor IX inhibitors 
(Bethesda assay or 
Nijmegen modified 
Bethesda assay) for 
local monitoring and 
eligibility check k 
x 
 
 
x 
x 
 
 
 
x: Visit F6, 
F12 
(W6, W12) 
x: Visit 
F15 (M6) 
x 
(x) f 
Transaminases 
(AST/ALT) for local 
monitoring l 
x 
 
x 
x 
x 
 
 
 
x 
x 
x 
(x) f 
Central 
Laboratory 
 
 
 
 
 
 
 
 
 
 
 
 
One-stage aPTT for 
factor IX activity  
 
x 
x 
x 
x 
 
 
 
x 
x 
x 
(x) f 
Chromogenic Assay 
for factor IX activity 
 
x 
x 
x 
x 
 
 
 
x 
x 
x 
(x) f 
Factor IX protein 
concentration 
 
x 
 
x 
x 
 
 
 
x 
x 
x 
(x) f 
Anti-factor IX 
antibodies  
 
 
 
 
x 
 
 
 
x: Visit F6, 
F12 
(W6, W12) 
x: Visit 
F15 (M6) 
x 
(x) f 
Factor IX inhibitors  
(Nijmegen modified 
Bethesda assay) k 
x 
 
 
x 
x 
 
 
 
x: Visit F6, 
F12 
(W6, W12) 
x: Visit 
F15 (M6) 
x 
(x) f 
Factor IX recovery m 
 
 
 
x 
 
 
 
 
 
 
 
(x) f 
Total (IgM and IgG) 
antibodies to AAV5 
x 
 
x 
x 
x 
 
 
 
x: Visit F3, 
F6, F9, F12 
(W3, W6, 
W9, W12) 
x: Visit 
F15 (M6) 
x 
(x) f 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
 
 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 30 of 150 
Trial Period a 
Screening 
Lead-in b, c, d 
IMP Dose 
Administration d 
Post-treatment Follow-up d, e 
Additional 
Visits f 
Day / Week / 
Month 
Visit S 
Visit L1 
(L-W0)g 
Visit L2 
to LX 
(every 2 
months, 
starting 
at L-M2) 
Visit  
L-Final 
Visit D 
pre-IMP 
Visit D 
0h 
Visit D 
post-IMP 
3h i 
Visit D 
post-IMP 
8h j 
Visit F1 to 
F12 
(every week 
W1 to W12) 
Visit F13 
to F20 
(every 
month 
M4 to 
M11) 
Visit 
F-Final 
(M12/ 
W52) 
 
Visit window 
(days) 
- 28 
0 
± 14 
h 
0 
0 
± 15 
minutes 
± 15 
minutes 
± 2 
± 5 
± 5 
 
Neutralizing 
antibodies to AAV5 
x 
 
x 
x 
x 
 
 
 
x: Visit F3, 
F6, F9, F12 
(W3, W6, 
W9, W12) 
x: Visit 
F15 (M6) 
x 
(x) f 
AAV5 capsid-
specific T cells 
 
 
 
 
x 
 
 
 
x 
x 
x 
(x) f 
Sampling for vector 
genome detection 
 
 
 
 
 
 
 
 
 
 
 
 
Blood n 
 
 
 
 
x 
 
x 
x 
x 
x 
x 
(x) f 
Semen n 
 
 
 
 
xo 
 
 
 
x: Visit F6, 
F12 
(W6, W12) 
x: Visit 
F13, F15 
(M4, M6) 
x 
(x) f 
Inflammatory 
markers 
IL-1β, IL-2, IL-6, 
IFNγ, MCP-1  
 
 
 
 
x 
 
 
 
x 
x 
x 
(x) f 
Alpha-fetoprotein 
(AFP) 
 
 
 
x 
 
 
 
 
 
x: Visit 
F15 (M6) 
x 
(x) f 
Hematology and 
coagulation 
parameters p 
x 
 
 
x 
x 
 
 
 
x  
x 
x 
(x) f 
Serum chemistry 
parameters q 
x 
 
 
x 
x 
 
x 
(only 
CRP) 
x 
(only 
CRP) 
x 
x 
x 
(x) f 
HIV, viral load, and 
CD4+ 
x 
 
 
x 
 
 
 
 
 
 
 
 
HBsAg, HBV DNA 
and HCV RNA 
x 
 
 
x 
 
 
 
 
 
 
 
 
Factor IX gene 
sequencing 
(optional) r 
x 
 
 
 
 
 
 
 
 
 
 
 
Blood sample for 
future research 
(optional) s 
x 
 
 
 
x 
 
 
 
x: Visit F12 
(W12) 
 
x 
 
AAV5: adeno-associated viral vector serotype 5; ALT: alanine aminotransferase; aPTT: activated partial thromboplastin time; AST: aspartate aminotransferase; CRP: C-Reactive Protein; 
DNA: deoxyribonucleic acid; h: hour; HBV: hepatitis B virus; HBsAg: hepatitis B surface antigen; HCV RNA: hepatitis C virus ribonucleic acid; HIV: human immunodeficiency virus; 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
 
 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 31 of 150 
IFNγ: interferon gamma; IgG: immunoglobulin G; IgM: immunoglobulin M; IL: interleukin: IMP: investigational medicinal product; M: month; MCP-1: monocyte chemotactic protein-1; 
W: week. 
a. 
This table shows events for screening, lead-in, and treatment + post-treatment follow-up. Refer to Table 4 for events during the long-term follow-up. 
b. 
Each visit in the lead-in phase is scheduled in relation to the date of L1 (L-W0), not in relation to the date of its previous visit. 
c. 
The lead-in phase will be a minimum of 6 months, ending at or before Visit D. Visits will occur every 2 months and between visits, there will be a follow-up telephone call for e-diary 
review (alternating months). 
d. 
For subjects on continuous routine prophylactic factor IX replacement therapy, these visits should take place on the day that routine prophylactic factor IX replacement treatment is 
planned to be administered. At these visits, blood sampling will take place prior to administration of prophylactic factor IX replacement therapy. If a subject uses additional on-demand 
factor IX replacement treatment, his upcoming study visit may need to be re-scheduled (to the extent the visit window allows) so that the visit takes place at the time the subject resumes 
his continuous routine prophylaxis schedule. For subjects only using on-demand factor IX replacement therapy (only applicable after CSL222 administration), his upcoming study visit 
may need to be re-scheduled (to the extent the visit window allows) so that the visit does not take place within 5 half-lives of exogenous factor IX product use. In case the 5 half-lives 
washout extends beyond the protocol-allowed visit window, the Medpace and/or CSL Behring Medical Directors are to be contacted to discuss how to proceed. 
e. 
Each visit in the post-treatment follow-up is scheduled in relation to the date of IMP dose administration (Visit D), not in relation to the date of its previous visit. 
f. 
An additional visit can be performed at any time during the study (lead-in or follow-up phases) for the purpose of conducting one or more procedures listed in the column “Additional 
Visits”, as per the preference of the Investigator. Hence, “(x)” refers to a procedure that can be performed, if judged relevant by the Investigator. 
g. 
Prior to the Visit L1, subjects will undergo a wash out period from their usual factor IX product/dose. The wash out period will be 3 days for regular-acting factor IX products and 
10 days for extended half-life factor IX products.  
h. 
Visit window for Visit L-Final is – 28 days (± 7 days) from Visit D. 
i. 
Applicable to all subjects excluding those in Germany. 
j. 
Applicable only to subjects in Germany.  
k. 
In case of a positive test for factor IX inhibitors, a re-test should be performed within 2 weeks to confirm the positive test. The subject should be called in for an additional visit in case 
no routine visit is scheduled within this 2-week timeframe. 
l. 
For ALT level increments of at least 2-fold baseline (ie, Visit D, pre-IMP) and/or > upper limit of normal (ULN), by local or central laboratories, the Investigator should contact the 
Medpace and/or CSL Behring Medical Directors to discuss a clinical management plan, on a case-by-case basis, including potential re-tests and/or initiation of corticosteroid treatment. 
In case of AST level increments > ULN, the Investigator should contact the Medpace and/or CSL Behring Medical Directors and a similar discussion should take place. 
m. At suspicion of factor IX inhibitor, the factor IX recovery assessment should be repeated. Blood samples for factor IX recovery assessment should be drawn prior to administering the 
subject’s continuous routine factor IX product/dose and at 30 minutes after the factor IX dose is administered (timed from end of infusion). The same continuous routine factor IX 
product/dose used at the baseline recovery assay should also be used when repeating the assay. 
n. 
Sampling for the individual subject and for a specific matrix (ie, blood or semen) is only to be continued until 3 consecutive negative samples have been detected for the subject for that 
particular type of matrix. The sampling schedule (frequency) may be increased as agreed between the Investigator and subject following the notification of a first negative result on 
blood and/or semen, expediting the opportunity to reach 3 consecutive negative samples on the specific matrix. Based on the wish of the subject, semen samples can be collected at 
home prior to attending the visit (at the visit day or at the day before the visit day). Also, the frequency of semen sampling may be reduced (to be agreed between Investigator and 
subject) as long as the subject uses a condom during sexual intercourse until 3 consecutive negative samples have been detected. 
o. 
Subjects travelling for Visit D may provide their semen sample at Visit L-Final. 
p. 
For hematology: Hemoglobin, hematocrit, platelet count, red blood cells, white blood cells with differential count (all expressed in % as well as in absolute numbers); for coagulation: 
aPTT, and PT (INR). 
q. 
Serum electrolytes (sodium, potassium), creatinine, creatine kinase, gamma-glutamyltransferase (ɣGT), AST, ALT, alkaline phosphatase (ALP), CRP, albumin, total bilirubin, glucose 
(non-fasting). 
r. 
Performed for all subjects who have provided separate informed consent for factor IX gene sequencing analysis. Preferably at the screening visit, but otherwise at a later time point 
during the subject’s trial participation. 
s. 
Only if separate informed consent is given by the subject. 
 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
 
 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 32 of 150 
Table 3 
Schedule of Events for Efficacy and Safety Evaluation, for Long-term Follow-up (Visit LTF1 to LTF8) 
Trial Period a 
Long-term Follow-up b, c 
Additional 
Visits d 
Visit 
LTF1 
LTF2 
LTF3 
LTF4 
LTF5 
LTF6 
LTF7 
LTF8 
 
Month 
18 
24 
30 
36 
42 
48 
54 
60 
 
Visit window (weeks) 
± 2 
± 2 
± 2 
± 2 
± 2 
± 2 
± 2 
± 2 
 
Concomitant medication 
Continuous 
(x) d 
Collection of bleeding episodes and factor 
IX use data e 
x 
x 
x 
x 
x 
x 
x 
x 
(x) d 
Physical examination 
x 
x 
x 
x 
 
x 
 
x 
(x) d 
Blood and semen sampling (Table 4) 
x 
x 
x 
x 
x 
x 
x 
x 
(x) d 
Abdominal ultrasound f 
x 
x 
x 
x 
x 
x 
x 
x 
(x) d 
EuroQol EQ-5D-5L g 
 
x 
 
x 
 
x 
 
x 
 
iPAQ g 
 
x 
 
x 
 
x 
 
x 
 
WPAI g 
 
x 
 
x 
 
x 
 
x 
 
BPI g 
 
x 
 
x 
 
x 
 
x 
 
HAL g 
 
x 
 
x 
 
x 
 
x 
 
Hem-A-QoL g 
 
x 
 
x 
 
x 
 
x 
 
HJHS h 
 
x 
 
x 
 
x 
 
x 
 
PROBE (optional) g, i 
 
x 
 
x 
 
x 
 
x 
 
Musculoskeletal ultrasound (optional) j 
 
x 
 
x 
 
x 
 
x 
 
Adverse events k 
Continuous 
 
Discuss the option to participate in the 
long-term follow-up extension trial 
(CSL222_3003) 
 
 
 
 
 
 
 
x 
 
AE: adverse event; BPI: Brief Pain Inventory; h: hour; HAL: Hemophilia activities list; Hem-A-QoL: hemophilia specific quality of life index; HJHS: Hemophilia Joint Health Score; 
IMP: investigational medicinal product; iPAQ: international Physical Activity Questionnaire; PROBE: Patient Reported Outcomes, Burdens, and Experiences; QoL: Quality of Life; 
WPAI: Work Productivity and Activity Impairment Questionnaire. 
a. 
This table shows events for the long-term follow-up. Refer to Table 1 for events during screening, lead-in, and treatment + post-treatment follow-up. 
b. 
Each visit in the long-term follow-up is scheduled in relation to the date of IMP dose administration (Visit D), not in relation to the date of its previous visit. 
c. 
For subjects on continuous routine prophylactic factor IX replacement therapy, these visits should take place on the day that routine prophylactic factor IX replacement treatment is 
planned to be administered. At these visits, blood sampling will take place prior to administration of prophylactic factor IX replacement therapy. If a subject uses additional on-demand 
factor IX replacement treatment, his upcoming study visit may need to be re-scheduled (to the extent the visit window allows) so that the visit takes place at the time the subject resumes 
his continuous routine prophylaxis schedule. For subjects only using on-demand factor IX replacement therapy (only applicable after CSL222 administration), his upcoming study visit 
may need to be re-scheduled (to the extent the visit window allows) so that the visit does not take place within 5 half-lives of exogenous factor IX product use. In case the 5 half-lives 
washout extends beyond the protocol-allowed visit window, the Medpace and/or CSL Behring Medical Directors are to be contacted to discuss how to proceed. 
d. 
An additional visit can be performed at any time during the study (long-term follow-up phase) for the purpose of conducting one or more procedures listed in the column “Additional 
Visits” as per the preference of the Investigator. Hence, “(x)” refers to a procedure that can be performed, if judged relevant by the Investigator. 
e. 
Subjects will record bleeding episodes and factor IX replacement therapy use in their study-specific paper long-term follow-up bleed diary and paper long-term follow-up factor IX use 
diary, which they will bring to every study visit. Site staff will collect the information that is new since the previous visit in the paper diaries. In between study visits, subjects should 
contact the site staff immediately in case of an experienced bleeding episode and/or factor IX use in addition to completing the questions/information requested on the paper diaries. 
Subjects who are on continuous routine factor IX prophylaxis during the long-term follow-up phase of the trial are required to contact the site staff immediately in case of a bleeding 
episode and/or factor IX use different from their routine factor IX prophylaxis, in addition to completing the questions/information requested on the paper diaries to capture all 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
 
 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 33 of 150 
information. The visit frequency is every 26 weeks (6 months) in this long-term follow-up phase, however, there should also be at least quarterly contact (± 2 weeks) between the site 
staff and subject to monitor the proper completion of the study-specific paper diaries, and proper reporting of factor IX usage and bleeding episodes. 
f. 
For those subjects where a long-term follow-up visit is impacted by COVID-19, abdominal ultrasounds may be conducted within the following window: up to – 1 month prior to the 
target visit and up to + 1 month after the target visit. Adjustments to the visit timing within this window are to be documented. 
g. 
It is recommended that the patient reported outcome (PRO) questionnaires (EQ-5D-5L/iPAQ/WPAI/BPI//HAL/Hem-A-QoL) are completed by the subject before he is seen by the 
Investigator and/or study nurse for interview and before other (trial specific) assessments are performed, as well as before the administration of IMP, in order for the answers not to be 
influenced by the information given by the physician, by the administration of IMP, or by early side-effects of the IMP or (trial related) assessments. At each visit, the questionnaires are 
to be completed in the same order every time, following the order presented in the protocol. The questionnaires are to be completed under site supervision at the site. For those subjects 
where the LTF2 (Month 24), LTF4 (Month 36), LTF6 (Month 48), and/or LTF8 (Month 60) visits are impacted by COVID-19, the questionnaires may be conducted at the site within 
the following window: up to – 1 month prior to the target visit, up to + 2 months after the target visit, and at least 4 months after the last assessment. Adjustments to the visit timing 
within this window are to be documented. 
h. 
In case of a bleeding episode occurring within 2 weeks before a scheduled LTF visit at which the HJHS assessment should be completed, the study visit should be re-scheduled. The 
Medpace and/or CSL Behring Medical Directors should be contacted to discuss how to proceed in case the visit would need to be pushed out beyond the protocol-allowed visit window. 
i. 
Applicable only for subjects participating in the optional PROBE questionnaire sub-study. For those subjects where the LTF2 (Month 24), LTF4 (Month 36), LTF6 (Month 48), and/or 
LTF8 (Month 60) visits are impacted by COVID-19, the PROBE questionnaire may be conducted at the site within the following window: up to – 1 month prior to the target visit, up to 
+ 2 months after the target visit, and at least 4 months after the last assessment. Adjustments to the visit timing within this window are to be documented. 
j. 
Applicable only for subjects participating in the optional musculoskeletal ultrasound (MSKUS) sub-study. For those subjects where the LTF2 (Month 24), LTF4 (Month 36), LTF6 
(Month 48), and/or LTF8 (Month 60) visits are impacted by COVID-19, scans may be conducted within the following window: up to – 1 month prior to the target visit, up to + 2 
months after the target visit, and at least 4 months after the last MSKUS. Adjustments to the visit timing within this window are to be documented. 
k. 
The visit frequency is every 26 weeks (6 months) in this long-term follow-up phase, however there should be at least quarterly contact (± 2 weeks) between the site staff and subject to 
monitor the occurrence of AEs. 
 
 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
 
 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 34 of 150 
Table 4 
Schedule of Events for Laboratory Parameters, for Long-term Follow-up (Visit LTF1 to LTF8) 
Trial Period a 
Long-term Follow-up b, c 
Additional 
Visits d 
Visit 
LTF1 
LTF2 
LTF3 
LTF4 
LTF5 
LTF6 
LTF7 
LTF8 
 
Months 
18 
24 
30 
36 
42 
48 
54 
60 
 
Visit window (weeks) 
± 2 
± 2 
± 2 
± 2 
± 2 
± 2 
± 2 
± 2 
 
Local Laboratory 
 
 
 
 
 
 
 
 
 
Factor IX: one-stage aPTT for factor IX 
activity for local monitoring 
x 
x 
x 
x 
x 
x 
x 
x 
(x) d 
Transaminases (AST/ALT) for local 
monitoring e 
x 
x 
x 
x 
x 
x 
x 
x 
(x) d 
Central Laboratory 
 
 
 
 
 
 
 
 
 
One-stage aPTT for factor IX activity 
x 
x 
x 
x 
x 
x 
x 
x 
(x) d 
Chromogenic Assay for factor IX activity 
x 
x 
x 
x 
x 
x 
x 
x 
(x) d 
Factor IX protein concentration 
x 
x 
x 
x 
x 
x 
x 
x 
(x) d 
Anti-factor IX antibodies  
 
x 
 
x 
 
x 
 
x 
(x) d 
Factor IX inhibitors 
(Nijmegen modified Bethesda assay) f 
 
x 
 
x 
 
x 
 
x 
(x) d 
Factor IX Recovery g 
 
 
 
 
 
 
 
 
(x) d 
Total (IgM and IgG) antibodies to AAV5 
 
x 
 
x 
 
x 
 
x 
(x) d 
Neutralizing antibodies to AAV5 
 
x 
 
x 
 
x 
 
x 
(x) d 
Sampling for vector genome detection 
x 
x 
x 
x 
x 
x 
x 
x 
(x) d 
Blood h 
x 
x 
x 
x 
x 
x 
x 
x 
(x) d 
Semen h 
x 
x 
x 
x 
x 
x 
x 
x 
(x) d 
Alpha-fetoprotein (AFP)  
x 
x 
x 
x 
x 
x 
x 
x 
(x) d 
Hematology and coagulation parameters i 
x 
x 
x 
x 
x 
x 
x 
x 
(x) d 
Serum chemistry parameters j 
x 
x 
x 
x 
x 
x 
x 
x 
(x) d 
Tumor, suspected malignancy, or liver 
tissue sampling for molecular analysis 
(optional) k  
x 
x 
x 
x 
x 
x 
x 
x 
(x) d 
AAV5: adeno-associated viral vector serotype 5; ALT: alanine aminotransferase; aPTT: activated partial thromboplastin time; AST: aspartate aminotransferase; IgG: immunoglobulin G; 
IgM: immunoglobulin M; IMP: investigational medicinal product. 
a. 
This table shows events for the long-term follow-up. Refer to Table 2 for events during screening, lead-in, and treatment + post-treatment follow-up. 
b. 
Each visit in the long-term follow-up is scheduled in relation to the date of IMP dose administration (Visit D), not in relation to the date of its previous visit. 
c. 
For subjects on continuous routine prophylactic factor IX replacement therapy, these visits should take place on the day that routine prophylactic factor IX replacement treatment is 
planned to be administered. At these visits, blood sampling will take place prior to administration of prophylactic factor IX replacement therapy. If a subject uses additional on-demand 
factor IX replacement treatment, his upcoming study visit may need to be re-scheduled (to the extent the visit window allows) so that the visit takes place at the time the subject resumes 
his continuous routine prophylaxis schedule. For subjects only using on-demand factor IX replacement therapy (only applicable after CSL222 administration), his upcoming study visit 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
 
 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 35 of 150 
may need to be re-scheduled (to the extent the visit window allows) so that the visit does not take place within 5 half-lives of exogenous factor IX product use. In case the 5 half-lives 
washout extends beyond the protocol-allowed visit window, the Medpace and/or CSL Behring Medical Directors are to be contacted to discuss how to proceed. 
d. 
An additional visit can be performed at any time during the study (long-term follow-up phase) for the purpose of conducting one or more procedures listed in the column “Additional 
Visits” as per the preference of the Investigator. Hence, “(x)” refers to a procedure that can be performed, if judged relevant by the Investigator. 
e. 
For ALT level increments of at least 2-fold baseline (ie, Visit D, pre-IMP) and/or > upper limit of normal (ULN), by local or central laboratories, the Investigator should contact the 
Medpace and/or CSL Behring Medical Directors to discuss a clinical management plan, on a case-by-case basis, including potential re-tests and/or initiation of corticosteroid treatment. 
In case of AST level increments > ULN, the Investigator should contact the Medpace and/or CSL Behring Medical Directors and a similar discussion should take place. 
f. 
In case of a positive test for factor IX inhibitors, a re-test should be performed within 2 weeks to confirm the positive test. The subject should be called in for an additional visit in case 
no routine visit is scheduled within this 2-week timeframe. 
g. 
At suspicion of factor IX inhibitor, the factor IX recovery assessment should be repeated. Blood samples for factor IX recovery assessment should be drawn prior to administering the 
subject’s continuous routine factor IX product/dose and at 30 minutes after the factor IX dose is administered (timed from end of infusion). The same continuous routine factor IX 
product/dose used at the baseline recovery assay should also be used when repeating the assay. 
h. 
Sampling for the individual subject and for a specific matrix (ie, blood or semen) is only to be continued until 3 consecutive negative samples have been detected for the subject for that 
particular type of matrix. The sampling schedule (frequency) may be increased as agreed between the Investigator and subject following the notification of a first negative result on 
blood and/or semen, expediting the opportunity to reach 3 consecutive negative samples on the specific matrix. Based on the wish of the subject, semen samples can be collected at 
home prior to attending the visit (at the visit day or at the day before the visit day). Also, the frequency of semen sampling may be reduced (to be agreed between Investigator and 
subject) as long as the subject uses a condom during sexual intercourse until 3 consecutive negative samples have been detected. Semen samples are only to be collected as applicable.  
i. 
For hematology: hemoglobin, hematocrit, platelet count, red blood cells, white blood cells with differential count (all expressed in % as well as in absolute numbers); for coagulation: 
aPTT, and prothrombin time (or INR [International Normalized Ratio]). 
j. 
Serum electrolytes (sodium, potassium), creatinine, creatine kinase, gamma-glutamyltransferase (ɣGT), aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline 
phosphatase (ALP), C-Reactive Protein (CRP), albumin, total bilirubin, glucose (non-fasting). 
k. 
The Sponsor will provide an optional informed consent to ask subjects to agree with providing a sufficiently sized tissue sample if they are diagnosed with a new tumor or suspected 
malignancy involving the liver or other tissue for which there is evidence of biological plausibility of vector integration, or if a sample of the subject’s liver tissue becomes available for 
any other reason. Samples will be obtained during a standard of care procedure (eg, during a biopsy, liver transplant, or resection) or through a planned autopsy upon the subject’s death, 
and molecular analysis will be conducted, when possible, on the sample(s) (Section 6.2.4.2). 
 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 36 of 150 
1 INTRODUCTION 
1.1 Condition Background and Current Treatment 
Congenital hemophilia B is an inherited bleeding disorder characterized by an increased bleeding 
tendency due to either a partial or complete deficiency of the essential blood coagulation 
factor IX (FIX). The deficiency is the result of mutations of the respective clotting factor genes. 
Hemophilia B is an X-linked, recessive condition, since it occurs almost exclusively in males. 
Females typically are asymptomatic carriers. The number of people with hemophilia B 
worldwide is approximately 30,000 and in the United States (US) alone is approximately 4,000 
(World Federation of Haemophilia [WFH], 2017). Approximately 1 in 20,000 – 50,000 live male 
newborns has hemophilia B. 
The severity of symptoms can vary and the severe forms become apparent early in life. About 
one-third of individuals with hemophilia B have a severe disorder characterized by functional 
factor IX levels that are less than 1% of normal (Kessler & Mariani, 2006). Moderate and mild 
hemophilia B, with 1 to 5% or 5 to < 40% of normal factor IX level, respectively, are each 
observed in about one-third of patients (Kessler & Mariani, 2006). 
Bleeding is the main symptom of the disease and usually increases when the infant becomes 
mobile. Mild cases may go unnoticed until later in life, when they occur in response to surgery or 
trauma. In severe or moderate hemophilia internal bleeding may occur anywhere, but bleeding 
into joints is most common (National Heart, Lung, and Blood Institute, 2013). Severe recurrent 
bleeding episodes may lead to severe arthropathy, joint contractures and pseudotumors, resulting 
in chronic pain, disability and reduced quality of life (QoL) (Bolton-Maggs et al, 2003). As few 
as 1 to 2 bleeding episodes can trigger progressive, irreversible joint disease (Gater et al, 2011). 
The overall life expectancy in severe hemophilia is 63 years, which is about 15 years lower than 
general male population (Darby et al, 2007). Life expectancy in patients without liver 
complications (eg, human immunodeficiency virus [HIV] or hepatitis C) can approach that of the 
general male population (Plug et al, 2006; Osooli et al, 2017). 
There is no cure for hemophilia B. The primary goals of hemophilia B therapy are the prevention 
of bleeding episodes, rapid and definitive treatment of bleeding episodes (breakthrough bleeds) 
that occur even while on a regular prophylactic regimen and provision of adequate hemostasis 
during surgery and emergencies. Currently, these goals are essentially met for hemophilia B 
subjects by intravenous (IV) injections of commercially available recombinant- or 
plasma-derived factor IX products, either at the time of a bleed (on-demand) or by regular 
infusions up to several times a week (prophylactically). The recent approvals of extended 
half-life factor IX products allow for reduced frequency of factor administration (once every 7 to 
14 days) and maintaining a higher factor IX trough level (Taylor and Kruse-Jarres, 2016). 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 37 of 150 
1.2 Gene Therapy Therapeutic Concept 
Somatic gene therapy offers the potential for a shift of the disease severity phenotype from 
severe to a moderate or mild hemophilia phenotype or complete amelioration through continuous 
production of stable factor IX levels after a single administration of vector, especially since a 
small rise in circulating factor IX to at least 1% of normal levels can substantially ameliorate the 
bleeding phenotype and thus improve the QoL for patients. 
1.3 Investigational Product Background 
CSL222 (formerly AMT-061) has been developed for the treatment of hemophilia B. CSL222 is 
a recombinant adeno-associated viral vector serotype 5 (rAAV5) containing the coding sequence 
for the Padua variant of the human coagulation factor IX (hFIX-Padua), codon optimized for 
optimal expression in humans, under control of a liver-specific promoter (also known as 
AAV5-hFIXco-Padua). 
CSL222 is a derivative of CSL220 (formerly AMT-060), which has been studied in a Phase I/II 
clinical trial in humans with severe or moderately severe hemophilia B. Both CSL220 and 
CSL222 have the same recombinant AAV5 containing the codon-optimized wild-type human 
factor IX gene, but the latter incorporates a 2-nucleotide change in order to encode the naturally 
occurring Padua variant of human coagulation factor IX. The FIX-Padua protein differs from the 
“wild-type” human factor IX protein by a single amino acid, and it is responsible for the 
observed increased factor IX activity per unit of dose achieved with CSL222 as compared to its 
predecessor CSL220. 
Both CSL220 and CSL222 employ the same AAV5 capsid as vector and liver-specific promoter, 
conferring similar safety and expression profiles. Section 1.3.1 provides a summary of the 
preclinical information for CSL220 and CSL222. Clinical information for CSL220 is 
summarized in Section 1.3.2. For the most comprehensive information regarding CSL220 and 
CSL222, refer to the most recent Investigator’s Brochure. 
CSL222 (HEMGENIX®) used in CSL222_3001 (formerly CT-AMT-061-02) is authorized in the 
European Union (EU), US, and other countries and is used in this trial in accordance with the 
terms of the marketing authorization. 
1.3.1 Preclinical Information 
Information for CSL222 (Formerly AMT-061) 
The CSL220 and CSL222 based gene therapy vectors are identical with the exception of a 
2-nucleotide substitution resulting in a single codon change (AGG to CTG) in the coding 
sequence for factor IX present in CSL222, corresponding to an Arginine to Leucine substitution 
in the transgenic protein. 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 38 of 150 
The R338L substitution, FIX-Padua, represents a naturally occurring variant of factor IX 
showing a gain-of-function, which results in higher factor IX activity with similar factor IX 
protein expression (Simioni et al, 2009). This augmentation is thought to be largely caused by 
increased affinity of the activated protein to activated clotting factor VIII (FVIIIa; 
Kao et al, 2013). Both CSL220 and CSL222 employ the same vector AAV5 without any changes 
and it is therefore expected that CSL222 will present a safety profile similar to that observed 
with CSL220. 
A non-human primate (NHP) study (NR-061-17-001) was performed to assess 4 different dose 
levels of CSL222 in direct comparison with CSL220 with respect to liver transduction, 
circulating factor IX protein levels, circulating factor IX activity levels and toxicity, after a single 
IV dose with 13 or 26-week observation period. The study comprised of measurements of 
circulating hFIX protein levels, total circulating factor IX activity levels, assessment of vector 
DNA in plasma, biodistribution including more than 25 different organs/tissues, complete safety 
panel routinely performed in GLP-toxicity studies and monitoring of 6 different liver enzymes 
and additional coagulation markers throughout the study. The study revealed dose dependent 
plasma vector DNA levels, human factor IX protein levels and factor IX activity for CSL222. 
Clinical signs were unaffected by treatment as well as clinical chemistry and hematology. 
Coagulation investigations up to 26 weeks revealed a shortening of the activated partial 
thromboplastin time (aPTT) and longer PT clotting times at the highest dose (9.0 × 1013 genome 
copies [gc]/kg) of CSL222 only, without an effect on plasma D-dimer and 
thrombin-antithrombin levels, suggesting that despite the effect on the clotting times, the overall 
clotting cascade is functioning within physiological boundaries. The study clearly showed that at 
a dose of 5 × 1012 gc/kg, plasma exposure, liver distribution, liver cell transduction, and 
transgene expression are similar for both CSL220 and CSL222, but the transgene activity is 
approximately 6 times higher per unit protein for CSL222 compared to CSL220. Although the 
study design only included a direct comparison at 5 × 1012 gc/kg, it can be expected that plasma 
exposure, liver distribution, liver cell transduction, and transgene expression behave similarly at 
each dose level with a range. As expected, the study demonstrated that for the same dose, the 
mean factor IX protein of CSL220 (average of 4.89, ranging from 3.17 to 7.61%) and CSL222 
(average of 4.85, ranging from 2.92 to 6.17%) was comparable. The confirmation of transgene 
activity being approximately 6 times higher per unit protein (average of 6.10, ranging from 
5.41 to 7.47%) can similarly be expected to result in multiple of the already demonstrated 
activity levels of CSL220 within a range. These results are comparable to the increase in 
gain-of-function reported for the Padua factor IX protein compared with “wild-type” factor IX 
protein in animal models (Crudele et al, 2015; Monahan et al, 2015). 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 39 of 150 
The observed translation of the NHP for CSL220 to the clinical Phase I/II for CSL220 supports 
the translation of the NHP study for CSL222 (NR-061-17-001, Study No. NC1615) to further 
inform the dose rationale for the dose confirmation trial (CSL222_2001 [formerly 
CT-AMT-061-01]) with 2 × 1013 gc/kg CSL222. At 2 × 1013 gc/kg, CSL222 is predicted to result 
in mean factor IX activity ranges of 40% of normal, with acceptable ranges (between 
approximately 18 to 76%) within the expected safety for factor IX replacement (upper bound of 
the safety and therapeutic target range is 129%). 
The other nonclinical study was a formulation bridging study in wild-type male mice to test 
CSL222, manufactured as per process used to manufacture the material for the pivotal clinical 
trial, in direct comparison with CSL220, both tested at 3 different concentrations (formulated 
with or without polysorbate-20). This study showed a similar dose-dependent expression of hFIX 
protein levels in plasma, supporting equal transgene expression mediated by the 2 products.  
The nonclinical studies with CSL222 indicated that CSL222 has a comparable distribution and 
plasma shedding profile to CSL220, which was not influenced by the addition of polysorbate-20 
to the formulation. The addition of the polysorbate-20 to the formulation had no effect on the 
safety profile of CSL220 and CSL222 in wild-type mice. 
Information for CSL220 (Formerly AMT-060) 
A range of in vivo studies in wild-type and hemophilia B mice and in NHPs have been performed 
to characterize the safety and pharmacology of CSL220. 
Pharmacology studies in mice and NHPs showed that infusion of CSL220 resulted in vector 
dose-dependent circulating levels of (human) factor IX protein. 
To verify that CSL220 mediates expression of biologically active hFIX, and to confirm that the 
hFIX produced and secreted into the circulation can ameliorate the clotting defect inherent to 
factor IX deficiency, a dose-range study was performed in a murine model of hemophilia B 
(Study NR-060-13-007). Results of this study indicated direct correlation in vivo between 
circulating human factor IX protein levels and human factor IX activity. 
In both Rhesus and Cynomolgus macaques injected with various doses of CSL220, the resulting 
hFIX expression correlated with the dose and was sustained for the duration of the 6 months 
follow-up (Cynomolgus macaque; Study 522156 and NR-060-14-006) and 90 days follow-up 
(Rhesus monkey; Study 520665 and NR-060-11-009). 
None of the animals presented elevated liver enzyme levels or other signs of toxicity during the 
whole observation period, and after sacrifice no abnormalities were observed in the liver. 
These nonclinical data suggest that IV administration of CSL220 is able to mediate sustained 
levels of factor IX, and that such administration is not associated with any significant safety 
concerns. 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 40 of 150 
1.3.2 Preliminary Clinical Information for CSL222 and Clinical Information for CSL220 
The combination of an AAV5 vector and the human factor IX gene (AAV5-hFIX) had not been 
evaluated in human trials prior to the initiation of the Sponsor’s Phase I/II clinical trial 
CSL220_1001 (formerly CT-AMT-060-01). The AAV5 capsid and the hFIX gene cassette have 
been tested individually in other Phase I/II clinical trials. Results that were available from these 
trials at the time the original protocol for CSL222_3001 (dated 16 Feb 2018) was developed 
provided preliminary clinical evidence for the efficacy and safety of CSL222 and are 
summarized in Section 1.3.2.1. Interim results that were available from the first-in-human trials 
for CSL220 (CSL220_1001) and CSL222 (CSL222_2001) at the time the original protocol for 
CSL222_3001 was developed are summarized in Section 1.3.2.2 and Section 1.3.2.3, 
respectively. 
1.3.2.1 Preliminary Clinical Evidence for Efficacy and Safety of Components of CSL222 
In Table 5, the most relevant published data and studies conducted with AAV capsids and hFIX 
that were identified through searches of PubMed and clinicaltrials.gov databases are presented. 
The data outlined below support that administration of CSL222 will be safe, well-tolerated, and 
able to generate sustained endogenous production of factor IX at clinically meaningful activity 
levels. 
Table 5 
Summary of Published Clinical Experience with Components of CSL222 
Reference 
Capsid 
Gene 
Promotor 
Target 
tissue 
Key Findings 
D’Avola et al, 
2016 
AAV5-
based 
PBGD 
-- 
Liver 
- 
No adverse events associated with 
capsid 
- 
Capable of transducing hepatocytes in 
vivo  
Rangarajan et 
al, 2017 
AAV5 
BDD-
FVIII 
APOE 
HCR/A1AT 
Liver 
- 
Mild asymptomatic transaminase 
increases in 7 subjects 
- 
Capable of delivery that results in 
clinically relevant transgene 
expression durable to > 1 year 
Lu et al, 1993 
Retro-viral 
hFIX 
LTR 
N2CMV 
Autologous 
skin 
fibroblasts 
- 
Increase in factor IX activity and 
improved symptoms in 1 subject 
- 
No safety or toxicity concerns 
Kay et al, 2000 
AAV2 
hFIX 
CMV 
Muscle 
- 
Expression of biologically active 
hFIX 
- 
No inhibitors to factor IX 
Manno et al, 
2003 
AAV2 
hFIX 
CMV 
Muscle 
- 
Safe incorporation of hFIX into 
muscle cells 
- 
Persistence of vector genome and 
protein expression to 10 months 
- 
No inhibitors to factor IX 
Jiang et al, 
2006 
AAV2 
hFIX 
CMV 
Muscle 
- 
Persistence of vector genome and 
local protein expression at 3.7 years 
post-treatment 
- 
No inhibitors to factor IX 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 41 of 150 
Reference 
Capsid 
Gene 
Promotor 
Target 
tissue 
Key Findings 
Manno et al, 
2006 
AAV2 
hFIX 
hAAT-
APOE 
Liver 
- 
Transient expression of factor IX at 
clinically relevant doses by transduced 
hepatocytes  
- 
Loss of factor IX expression with 
ALT increase 
- 
No inhibitors to factor IX or T-cell 
response to the capsid 
Nathwani et al, 
2011, 2014, 
2018 
AAV8 
hFIXcoa 
LP1a 
Liver 
- 
Successful transduction of hepatocytes 
resulting in clinically relevant 
increases in serum factor IX activity  
- 
Clinically relevant increases in 
factor IX activity sustained up to 
approximately 8 years 
- 
Elevated transaminases in 4 subjects; 
factor IX expression retained in 2 with 
corticosteroid treatment 
- 
No inhibitors to factor IX 
- 
No late toxicity 
George et al, 
2017 
Undisclosed 
hFIX-
Padua 
hAAT-
APOE 
Liver 
- 
Clinically relevant increases in factor 
IX activity sustained to > 1 year 
- 
Elevated transaminases in 2 subjects; 
partial to full factor IX activity 
retained with corticosteroid treatment 
- 
No inhibitors to factor IX 
AAV5/AAV2/AAV8: adeno-associated viral vector of serotype 5 (or 2 or 8); ALT: alanine aminotransferase; 
APOE: apolipoprotein E; BDD-FVIII: B-domain deleted factor VIII; CMV: Cytomegalovirus; hAAT: human α1-antitrypsin; 
hFIX: human factor IX; LTR: long terminal repeat; PBGD: porphobilinogen deaminase. 
a  
Same transgene expression cassette as is used for CSL220 
 
AAV5 Capsid 
Two studies of the AAV5 capsid in humans were identified. 
D’Avola et al (2016) studied the AAV5-based vector comprising the capsid shell of CSL220 and 
containing a functional porphobilinogen deaminase (PBGD) gene tested at varying doses 
(5 × 1011 to 1.8 × 1013 gc/kg; single IV infusion) in 8 adult subjects with intermittent acute 
porphyria. One subject failed screening due to pre-existing AAV5 neutralizing antibodies 
(NABs). All 8 subjects who received AAV5-PBGD were followed for 1 year. No 
treatment-related adverse events (AEs) were observed during the infusion or the follow-up 
period. One subject who received the highest dose experienced a mild increase (< 3 × upper limit 
of normal [ULN]) of liver transaminase levels 1 week after receiving AAV5-PBGD, coincident 
with an acute porphyria attack. Levels normalized once the attack resolved. As expected, all 
subjects developed antibody titers against AAV5; no subjects developed antibodies against the 
transgene product. The AAV5 vector was cleared from all bodily secretions by 30 days 
post-administration. Together, these findings support good safety and tolerability for the AAV5 
capsid. Evaluation of liver biopsies at 1-year post-treatment showed persistence of vector 
genomes and transgene messenger RNA in all 6 subjects evaluated, suggesting that the AAV5 
capsid is able to effectively deliver genetic material to the nuclei of liver cells. 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 42 of 150 
Initial results up to 52 weeks post-treatment have also reported by Rangarajan et al (2017) from a 
Phase I/II trial of an AAV5-B-domain-deleted factor VIII (FVIII) construct in 9 adults with 
hemophilia A. In this report, subjects received doses ranging from 6 × 1011 to 6 × 1013 gc/kg via 
single IV infusion. No serious adverse events (SAEs) attributable to treatment were observed. 
The first subject receiving the highest dose experienced a mild increase in transaminase levels, 
which resolved with a short course of corticosteroids; subsequent subjects received prophylactic 
steroid treatment, of whom 6 experienced mild transient increases in their transaminase levels. 
One subject experienced a decline in FVIII activity from 227 IU/dL to 52 IU/dL in conjunction 
with an increase in alanine aminotransferase (ALT) occurring after discontinuation of 
prophylactic steroids. A second course of corticosteroids was initiated and FVIII subsequently 
increased. No clear relationship was observed between corticosteroid use and resolution of 
elevated aminotransferase. All subjects have tapered off corticosteroids and continue to 
demonstrate increased FVIII activity at 1 year. 
Together, these findings support a strong expected safety profile of the AAV5 capsid in humans, 
with no serious safety concerns emerging. Mild, asymptomatic liver transaminase increases are 
the most common event, consistent with reports from other liver-targeted AAV serotypes. 
Together, these studies provide evidence that the AAV5 capsid is capable of transducing human 
hepatocytes in vivo, resulting in detectable, sustained transgene expression. 
Gene cassette 
Gene transfer of the human wild-type factor IX gene has been evaluated in 3 key studies in adult 
subjects with hemophilia B. The most recent reports demonstrate that this construct is capable of 
inducing sustained, clinically relevant increases in factor IX activity without associated safety 
concerns. 
In 3 subjects receiving transfer of the wild-type hFIX gene under control of a cytomegalovirus 
(CMV) promotor/enhancer (2 × 1011 gc/kg) into the muscle via AAV2, evidence of factor IX 
protein expression was seen both in the circulation and through histological examination of 
muscle biopsies (Kay et al, 2000). Factor IX consumption was reduced in 2 subjects, providing 
evidence of biological activity of the secreted protein. Five additional subjects were then dosed 
up to 1.8 × 1012 gc/kg. Presence and expression of the transgene was demonstrated via 
polymerase chain reaction (PCR) and Southern blot in muscle biopsies up to Month 10 
post-injection. No muscle tissue abnormalities were noted, suggesting the cells were not 
damaged by incorporation of the vector genome (Manno et al, 2003). Follow-up of 1 subject 
3.7 years after injection showed persistence of the vector genome and protein expression locally 
in the muscle (Jiang et al, 2006). 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 43 of 150 
A subsequent trial examined the effects of the wild-type hFIX under control of a liver-specific 
human ɑ1-antitrypsin (hAAT) promotor coupled with the apolipoprotein E (APOE) enhancer and 
hepatic control region, packaged into AAV2 vectors and administered via hepatic vein infusion 
to 7 subjects at doses up to 2 × 1012 gc/kg (Manno et al, 2006). No evidence of increased 
circulating factor IX activity was obtained at 8 × 1010 or 4 × 1011 gc/kg. At the highest dose, both 
subjects showed transient increases in circulating factor IX activity (approximately 12% and 3% 
of normal) which gradually returned to baseline. The high-responding subject demonstrated 
asymptomatic increases in serum transaminase levels coincident with the decline in factor IX 
activity that subsequently normalized. A second subject who received the middle dose also 
experienced an asymptomatic increase of serum transaminase levels that normalized without 
intervention. Testing in this subject indicated that no T-cell response developed to the factor IX 
protein. 
The cassette identical to that incorporated in CSL220, and forming the basis for the modified 
version incorporated in CSL222, has been examined in 10 subjects in a trial sponsored by 
St Jude’s and University College of London (Nathwani et al, 2011; Nathwani et al, 2014; 
Nathwani et al, 2018). Subjects received increasing doses (2 × 1011 to 2 × 1012 gc/kg; single IV 
infusion) of the LP1-hFIXco construct delivered via AAV8, resulting in a steady state of 1 to 6% 
normal factor IX activity that remained stable at last reported follow-up approximately 8 years 
after administration. Use of exogenous factor IX replacement was reduced by 92% following 
treatment. Bleeding episodes in the year after gene transfer decreased to a median of 1.5, 
compared with 15.5 in the year preceding treatment. Four of the 6 subjects who received the 
highest dose experienced increases in serum transaminase levels 7 to 10 weeks after 
administration and were treated with prednisolone, of whom 3 experienced an associated loss of 
factor IX activity. No subjects developed inhibitors to factor IX protein. All subjects 
demonstrated evidence of endogenous synthesis of factor IX from the transgene cassette. No 
evidence of late toxicity has emerged even at approximately 8 years post-treatment. 
Initial results have been published from a single study showing sustained factor IX expression 
driven by a gene cassette encoding a Padua variant factor IX (George et al, 2017). Ten subjects 
received a single IV dose of 5 × 1011 gc/kg, resulting in mean steady state factor IX expression of 
approximately 34% at 52 weeks at time of the report. Two subjects experienced increases of liver 
transaminases and were treated with prednisolone, of whom one experienced a partial loss of 
factor IX activity. No subjects developed inhibitors. 
Across all 3 studies, no subjects who had received gene transfer (total N = 31) developed 
inhibitors to the transgenic hFIX protein (Manno et al, 2003; Manno et al, 2006; 
Nathwani et al, 2014; George et al, 2017). 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 44 of 150 
1.3.2.2 Results of CSL220_1001 (Formerly CT-AMT-060-01) 
At the time the original protocol for CSL222_3001 was developed, enrollment and dosing in the 
first-in-human trial with CSL220 (CSL220_1001) was complete and follow-up of up to 2.5 years 
from all 5 subjects in the low dose (5 × 1012 gc/kg) cohort and 2 years follow-up from all 
5 subjects in the high dose (2 × 1013 gc/kg) cohort was available (Cohort 1 and 2, respectively; 
Leebeek et al, 2018; Miesbach et al, 2018). The durability of factor IX protein expression 
encoded by the codon optimized human coagulation factor IX complementary deoxyribonucleic 
acid (cDNA) obtained at this point in time was robust and sustainable. 
There were no deaths or AEs that resulted in discontinuation reported in CSL220_1001. There 
was a total of 3 SAEs assessed as treatment-related reported, including a febrile episode, 
elevation of liver enzymes, and elevation of ALT. Fourteen treatment-related AEs were reported 
in 6 subjects in the first 3.5 months post-treatment. There were no additional treatment-related 
AEs reported during this additional follow-up period up to 2.5 years post-treatment. Three 
subjects had mild, temporary ALT elevations 3 to 6 months post-treatment, which resolved with 
tapering courses of prednisolone with no recurrence. None of the observed ALT increases were 
associated with any concurrent loss of endogenous factor IX activity or capsid-specific T-cell 
response. No subject developed inhibitory antibodies to factor IX during the course of the trial. 
Following administration of CSL220, stable factor IX activity and clinically meaningful 
reductions in bleeds and exogenous factor IX use were observed, with disease severity improved 
in all subjects. The mean of all endogenous factor IX activity values measured post-treatment 
over the course of follow-up was 4.9% of normal in Cohort 1 and 7.4% of normal in Cohort 2. 
Eight of the 9 subjects who had been on factor IX prophylaxis at the time of trial entry no longer 
require factor IX prophylaxis after treatment with CSL220. Annualized exogenous factor IX use 
was reduced by ≥ 82% in Cohort 1 and ≥ 78% in Cohort 2 compared to pre-treatment. Mean 
annualized total bleeds decreased by ≥ 47% in Cohort 1 and ≥ 62% in Cohort 2. 
1.3.2.3 Interim Results for CSL222_2001 (Formerly CT-AMT-061-01) 
At the time the original protocol for CSL222_3001 was developed, enrollment and dosing in the 
dose confirmation Phase IIb trial with CSL222 (CSL222_2001) was complete and 3 subjects had 
been dosed with 2 × 1013 gc/kg of CSL222. An interim analysis was performed after all subjects 
had completed 6 weeks of post-treatment follow-up and the interim analysis data set included a 
combined 24 weeks of observation. The interim analysis results from CSL222_2001 were 
reviewed by the Data Monitoring Committee (DMC; Section 9.12) who recommended that a 
single dose of 2 × 1013 gc/kg of CSL222 be used in the treatment phase of this Phase III trial. 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 45 of 150 
There were no deaths, SAEs, or treatment-emergent adverse events (TEAEs) resulting in early 
discontinuation from CSL222_2001 at the time of the interim analysis. Overall, there were 
13 TEAEs reported in 2 of 3 subjects, including 2 treatment-related TEAEs reported in a single 
subject (C-reactive protein increased and headache). All TEAEs were mild in severity and the 
majority (11/13 events) were assessed as not related to study treatment. The system organ class 
(SOC) with the most reported events was Nervous System Disorders (4 events) and the most 
common TEAE was headache, reported in 2 subjects, though 1 subject experienced 6 separate 
events of pain. One subject had a mild, asymptomatic, and transient increase in liver enzyme 
levels (specifically, elevated aspartate aminotransferase [AST] levels) which resolved without 
any additional treatment and was not reported as a TEAE. No T-cell response was observed in 
any of the 3 subjects. None of the subjects developed inhibitory antibodies to factor IX. 
All 3 subjects had been diagnosed with severe hemophilia B with corresponding circulating 
factor IX activity levels < 1% of normal. A single dose of 2 × 1013 gc/kg of CSL222 was 
demonstrated to result in factor IX activity levels of ≥ 5% as early as 1-week post-treatment with 
mean ± standard deviation (SD) factor IX activity of 30.6 ± 6.97% (range: 23.9 to 37.8%) at 
Week 6 and 28.5 ± 6.42% (range 20.6 to 37.8%) across visits (factor IX activity was measured 
using the aPTT assay performed at a central laboratory). Factor IX activity was 37.1% of normal 
at 10 weeks after administration in the first subject, 23.3% of normal at 8 weeks following 
administration in the second subject, and 30.0% of normal at 6 weeks after administration in the 
third subject. The second and third subjects had previously screen-failed another gene therapy 
study due to pre-existing NABs to a different AAV vector. All 3 subjects had evidence of 
pre-existing NAB activity against adeno-associated viral vector serotype 5 (AAV5).  
In the year prior to screening, the number of treatment-requiring bleeding episodes ranged from 
1 to 5 spontaneous episodes and there was 1 moderate spontaneous bleeding episode in 1 subject 
in the period between screening and dosing. After dosing, there were no bleeding episodes, and 
the estimated annualized bleeding rate (ABR) was 0. Additionally, none of the subjects required 
any infusions of factor IX replacement therapy post-treatment with CSL222. 
1.4 Rationale for the Trial 
The current treatment options for hemophilia B have several limitations. Treatment with 
prophylactic regular IV injections of factor IX is not curative and very demanding due to the 
need for frequent IV infusions and concomitant risk for infection and thromboses related to the 
placement of indwelling catheters. Periodic or regular factor IX infusion results in peaks and 
troughs in plasma factor levels allowing for breakthrough bleeding episodes. Due to these 
factors, poor adherence to treatment is a concern and a major contributing factor to failure of 
prophylaxis, associated with increased risk of bleeding and subsequent joint damage, thereby 
adding to the all-cause mortality rate. There is also a risk of developing NABs against the 
administered factor IX. The burden of the disease is high, both for the individual subject and 
their families, and for society. Due to (long-term) impairments in mobility and functional status, 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 46 of 150 
subjects may not be able to fully participate in social activities, such as sports, school, or work. 
Living with hemophilia can have a substantial effect on mental wellbeing, particularly among 
young people and signs of major depressive disorder are not uncommon. The economic burden 
for society is significant. The cost of severe hemophilia, including indirect costs, is estimated at 
EUR 199,541 per subject in Europe, ranging from EUR 129,365 to 319,024 (O’Hara et al, 2017). 
Hemophilia subjects are accredited with requiring 2 to 3 times the health care resources per 
inhabitant in developed countries (Schramm & Berger, 2003). Hemophilia B thereby directly 
impacts the health-related QoL (Witkop et al, 2017). 
Somatic gene therapy for hemophilia B offers the potential for shift of the disease severity from 
severe to a moderate or mild hemophilic phenotype or complete amelioration through continuous 
endogenous production of factor IX protein after a single administration of AAV vector particles. 
Even a small rise in constantly circulating factor IX protein can substantially ameliorate the 
bleeding phenotype. 
Three subjects have been treated with 2 × 1013 genome copies (gc)/kg CSL222 in the dose 
confirmation Phase IIb trial (CSL222_2001). At the time the original protocol for CSL222_3001 
was developed, the initial treatment phase was complete in this study and an interim analysis 
based on a minimum of 6 weeks of post-treatment follow-up data for each subject had been 
performed (Section 1.3.2.3 for an overview of the interim analysis results). Overall, the dose of 
2 × 1013 gc/kg CSL222 was shown to be safe and well tolerated and resulted in mean factor IX 
activity levels approximately 30% of normal circulating factor IX 6 weeks after dosing. 
The results with CSL222 are complemented by robust efficacy and safety data obtained with 
CSL220 in the Phase I/II trial (CSL220_1001) in 10 subjects with hemophilia B who had been 
followed for up to 2.5 years after treatment at the time the original protocol for CSL222_3001 
was developed (Section 1.3.2.2 for an overview of study data). The data demonstrate that 
subjects achieved clinically relevant and stable factor IX activity levels for up to 2.5 years after 
treatment with CSL220. In addition, the CSL220 treatment remains to be safe and well-tolerated. 
The purpose of this Phase III trial is to demonstrate the efficacy of CSL222 in terms of 
endogenous factor IX activity and ABR, and to further describe its safety profile. The efficacy 
and safety results obtained during the Phase IIb study with CSL222 (CSL222_2001), 
supplemented with the strong efficacy and safety results obtained during the Phase I/II trial with 
CSL220 (CSL220_1001), demonstrate 2 × 1013 gc/kg to be the optimal dose for use in this 
pivotal Phase III trial. 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 47 of 150 
1.5 Risk/Benefit Considerations 
Somatic gene therapy for hemophilia B offers the potential benefit of a shift of the disease 
severity from severe to a mild hemophilia phenotype or complete amelioration through 
continuous endogenous production of factor IX after a single administration of vector. 
The identified risks are considered low and manageable and to not affect the risk/benefit balance 
in an unfavorable way. The optimized adeno-associated viral vector (AAV) approach has the 
potential to further limit the risks currently associated with AAV gene therapy approaches. 
The risks as described in the following sections have to be considered. 
1.5.1 Risk of Infusion-related Toxicity 
At the time the original protocol for CSL222_3001 was developed, no infusion-related toxicities 
had been observed in previous clinical trials of liver-directed gene transfer, including the 
CSL220_1001 trial. In CSL222_2001, 1 subject had mild TEAEs of headache and paresthesia 
reported on Day 1, which resolved the same day; the event of headache was assessed as possibly 
related to study treatment.  
As a precaution, subjects in this trial will be monitored for tolerance to the investigational 
medicinal product (IMP) and detection of potential immediate AEs at the clinical trial site for 
3 hours or 8 hours (only subjects in Germany) following infusion.  
1.5.2 Risk of Immune Mediated Neutralization of the AAV5 Gene Therapeutic Vector 
Pre-existence of antibodies that recognize a gene therapeutic vector can potentially reduce its 
bioavailability and hence its activity. For this reason, the eligibility criteria for CSL220_1001 
included the absence of detectable levels of circulating AAV5 NABs. Screening for AAV5 
NABs was performed using a bio-assay based on a green fluorescent protein (GFP) reporter 
gene. In line with previously reported low prevalence for AAV5 NABs (Boutin et al, 2010), no 
antibodies were detected, and all subjects passed screening. 
Recent availability of a more sensitive bio-assay, based on a luciferase reporter gene prompted 
retrospective analysis of the screening samples from the CSL220_1001 trial and pre-treatment 
samples of some of the nonclinical NHP studies. Retrospective analysis using this more sensitive 
assay revealed the presence of detectable levels of AAV5 NABs in 3 out of 10 CSL220_1001 
trial subjects and in all tested animals. However, judging by circulating factor IX activity levels 
or safety outcomes, these pre-existing AAV5 NAB levels held no predictive value: the 
CSL220_1001 trial subject showing the highest titer of 1/340 also showed highest circulating 
factor IX activity levels of this cohort, and in the NHPs no impact on efficacy was evident at 
titers up to 1/1000, at dose levels down to one-tenth of the low dose level in the CSL220_1001 
trial (ie, 5 × 1011 gc/kg versus 5 × 1012 gc/kg). 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 48 of 150 
These studies suggested that, although AAV5 NABs are prevalent in humans and NHPs, the 
absolute levels at which they are present may not suffice to impact CSL220 at the infused dose. 
In all subjects who were shown to have AAV5 NABs prior to treatment, factor IX activity 
remained stable, and none of the subjects showed evidence of liver toxicity or activation of 
T-cell responses against the capsid. As pre-existing antibody levels did not seem to preclude 
efficacy and were not associated with any immune-mediated adverse effect, the proposed trial 
will allow enrolment of subjects regardless of antibody levels. Nonetheless, AAV5 NAB levels 
will be measured in all subjects both before and after dosing, in order to allow a retrospective 
analysis to confirm the suggested lack of impact of prevalent titers on the efficacy of CSL222. 
For this, the more sensitive luciferase-based assay will be used. 
It is of note that after dosing of CSL222 all subjects will develop antibodies against the capsid 
proteins and these antibodies are likely to persist. In the Phase IIb trial, CSL222_2001, AAV5 
NABs were detected in all 3 subjects at Screening. As liver transduction will have taken place 
before these responses are fully mounted, these responses are unlikely to impact factor IX 
expression. However, they may impact the efficacy of any future administration (ie, a second 
dose) of the same vector, since post-dosing antibody levels may exceed prevalent pre-existing 
levels by several orders of magnitude. 
1.5.3 Risk of Immune Mediated Liver Toxicity 
IV administration of a liver-directed AAV vector might lead to transaminase increase. Previous 
clinical trials have shown that increases in liver enzymes respond promptly and normalize after 
administration of glucocorticoids. Subjects in the trial will be monitored weekly during the first 
12 weeks after infusion of CSL222 for the occurrence of transaminase increases, which, in the 
absence of an alternative etiology for the ALT increase, may warrant the initiation of a 
corticosteroid treatment (Section 5.6.2). 
At the time the original protocol for CSL222_3001 was developed, a transient increase in AST 
was noted in 1 subject in the CSL222_2001 trial, shortly after the infusion of CSL222. The 
subject had potentially clinically significant AST levels that were > 2 × baseline levels and 
slightly above the ULN at Week 4. The AST levels returned to within the normal range by 
Week 5. This increase in AST was not reported as a TEAE. 
In the CSL220_1001 trial, 3 subjects (1 subject in the low dose cohort and 2 subjects in the high 
dose cohort) had mild, asymptomatic increase of ALT. This is not an unexpected finding, as 
increases of transaminases have been observed in trials associated with gene therapy targeting 
the liver. It is important to note that in all 3 subjects none of the observed ALT increases was 
associated with any concurrent loss of endogenous factor IX activity. No evidence of immune 
reaction (eg, capsid-specific T-cell response) was associated with this increase. 

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1.5.4 Risks to Third Parties and the Environment Related to Shedding via Body Fluids 
The AAV vector will distribute systemically and small amounts of vector DNA have been 
observed in previous nonclinical and clinical studies in blood, urine, saliva, nasal secretion, feces 
and semen. In CSL222_2001, vector DNA was detected in all 3 subjects after at least 6, 8, or 10 
weeks of follow-up in blood and after 6 weeks of follow-up in semen. In CSL220_1001, vector 
DNA was detected at 78 weeks and later in semen and blood in some subjects. 
Vector DNA measured in these bodily fluids is unlikely to represent infectious particles. In 
addition, the vector is non-pathogenic and cannot replicate. Therefore, the risk for third parties 
such as family and health care personnel is considered marginal. Due to the incapacity of 
replication, the non-infectious nature of the shed DNA and the negligible amounts shed, the risk 
to the environment can be considered negligible. No specific containment or protection measures 
are deemed necessary. 
1.5.5 Risk of Vector DNA Integration into the Host Genome 
Reaction (nr LAM PCR) and subsequent high throughput sequencing on DNA was extracted 
from the livers of both mouse and Cynomolgus macaques after administration of CSL220 at 
various doses. There was no preferred integration in genes known to mediate malignant 
transformation or clonal dominance. Both episomal (concatemeric) and integrated forms of 
CSL220 were retrieved, but the sequences were present almost exclusively as non-integrated 
episomal forms. The retrieved integrants were randomly distributed throughout the host genome. 
No specific clustering was seen in Cynomolgus macaque genome, while some level of clustering 
around active genes was seen in the mouse. There were no signs of in vivo clone selection in the 
animals. 
1.5.6 Risk of Germ-line Transmission of Vector DNA 
The risk of germ line transmission is considered negligible for AAV-based vectors due to the 
marginal integration level of the vector DNA into the host genome. Any potential risk is 
addressed by requiring the use of a condom during the trial in the period from administration of 
the investigational drug until the AAV5 vector has been cleared from semen, as evidenced by 
negative analysis results for AAV5 vector for at least 3 consecutively collected semen samples. 
Additionally, subjects are asked to inform their partner of their participation in this trial, as well 
as the importance of contraception use to limit the reproductive potential in the period from IMP 
administration until AAV5 has been cleared from the semen. 

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1.5.7 Risk of Off-target Expression of the Transgene 
The vector will distribute systemically to all tissues thereby potentially infecting other cells than 
liver cells resulting in off-target gene expression. This risk is addressed by the use of a 
liver-specific promoter in the gene cassette. In other clinical trials using similar vector 
approaches, no AEs have been reported that could be related to potential off-target expression. 
1.5.8 Risk of Inhibitor Formation to Protein Expressed from the Transgene 
There is a risk of inhibitor/antibodies development against the expressed factor IX protein. At the 
time the original protocol for CSL222_3001 was developed, no factor IX inhibitor formation was 
seen in any of the previous clinical trials reported in literature where subjects were exposed to 
hFIX gene transfer and where the expressed levels of factor IX were measurable 
(Manno et al, 2003; Manno et al, 2006; Nathwani et al, 2011; Nathwani et al, 2014) or in 
CSL220_1001. In-silico studies indicate no higher risk of potential immunogenicity for factor IX 
protein expressed from CSL222 following incorporation of the single amino acid change as 
compared to the “wild-type” factor IX protein expressed from CSL220. Expression of a Padua 
transgene product did not result in inhibitors in studies conducted in murine and inhibitor-prone 
canine models (Cantore et al, 2012; Monahan, 2015; Crudele et al, 2015). In CSL222_2001, the 
formation of factor IX inhibitors was not detected in any of the 3 subjects at 6 weeks after 
dosing. 
To assist with minimizing this risk, subjects will be selected on the basis of a low risk of factor 
IX inhibitor development by choosing subjects with more than 150 exposure days to a factor IX 
product as well as omitting subjects with a previous factor IX inhibitor. Subjects will be 
regularly monitored for factor IX inhibitor development. 
1.5.9 Risk of Breakthrough Bleeding 
The scope of the liver-directed AAV gene therapy approach is to establish a stable and durable 
expression of factor IX and to convert to mild or completely ameliorate the severe hemophilia 
phenotype. Previous clinical trials with similar AAV vectors and the wild-type gene cassette 
have shown that stable and years long factor IX expression can be achieved 
(Nathwani et al, 2018). Nonetheless, there is a risk that breakthrough bleeding may occur, 
particularly if demanding physical activity is undertaken. This risk will be managed by the use of 
factor IX replacement as needed throughout the trial. Every effort will be made to avoid 
continuous routine use of prophylactic factor IX replacement therapy during the trial. 
In the Phase IIb trial with CSL222 (CSL222_2001), therapeutic levels of factor IX protein and 
resultant factor IX activity levels were seen as early as 1 week. In a previous trial with CSL220, 
therapeutic levels of factor IX protein and resultant factor IX activity levels were seen as early as 
1 week after treatment. In this trial, subjects will be administered a dose of their usual factor IX 
product/dose for the factor IX recovery assessment at Visit L-Final and will be permitted to 
continue their continuous routine factor IX treatment in the first week after dosing. 

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Additional on-demand factor IX may be given after treatment with CSL222, if considered 
necessary. Furthermore, subjects are monitored closely for 5 years after administration of IMP 
and the need for renewed prophylactic therapy will be clinically assessed by the treating 
physician according to the local standard of care for hemophilia subjects. 
1.6 Accommodations Due to the COVID-19 Pandemic 
In the first quarter of 2020, a pandemic was announced for Coronavirus Disease 2019 
(COVID-19) which is caused by the virus severe acute respiratory syndrome coronavirus 2 
(SARS-CoV-2). The pandemic impacted the conduct of clinical trials due to quarantines, site 
closures, travel limitations, diversion of resources and general interruptions in study related 
procedures, leading to protocol deviations. This study protocol includes contingency measures to 
manage disruptions due to COVID-19 control measures; see Section 3.1.1 for details on 
measures related to adjustments to visit location/method and schedule, as well as Section 6.2.2.4, 
Section 6.2.2.7, and Section 6.2.3.4 for new visit windows for QoL questionnaires, 
musculoskeletal ultrasound (MSKUS), and abdominal ultrasound assessments, respectively. The 
impacts of these implemented contingency measures on the outcomes of this study, including 
any protocol deviations that ultimately result from COVID-19 illness and/or COVID-19 control 
measures will be discussed in the Clinical Study Report (CSR). 
The decision to test a subject in the study for COVID-19 should be based on the site’s current 
guidelines and at the discretion of the Investigator. If a subject participating in the study is 
identified as a person under investigation, it is mandatory to immediately notify appropriate 
authorities as per site’s regulations and to notify Medpace and/or CSL Behring’s Medical 
Directors. As co-infections can occur, all subjects should be considered for COVID-19 virus 
testing regardless of whether another respiratory pathogen is found.  
If a subject is confirmed positive for COVID-19 at any time during the trial, the medical care, 
isolation, and management, should be according to national, local, institutional, and public health 
guidelines. 

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2 TRIAL OBJECTIVES 
2.1 Primary Objective 
The primary objective is to demonstrate the non-inferiority of CSL222 (2 × 1013 gc/kg) during 
the 52 weeks following establishment of stable factor IX expression (months 6 to 18) 
post-treatment (CSL222) follow-up compared to standard of care continuous routine factor IX 
prophylaxis during the lead-in phase, as measured by the ABR. 
2.2 Secondary and Exploratory Objectives 
The secondary objective is to demonstrate additional efficacy and safety aspects of systemic 
administration of CSL222. 
Secondary efficacy objectives are focused on investigating the effect of 2 × 1013 gc/kg CSL222 
on endogenous factor IX activity 6 months, 12 months, and 18 months after a single CSL222 
treatment, prevention of bleedings, assessment of trough factor IX activity, discontinuation of 
previous continuous routine prophylaxis, consumption of factor IX replacement therapy, 
occurrence and resolution of target joints, estimated ABR during the 52 weeks following stable 
factor IX expression (months 6-18 post-treatment) as a function of pre-IMP anti-AAV5 antibody 
titers using the luciferase-based NAB assay (as a “correlation” analysis), correlation of pre-IMP 
anti-AAV5 antibody titers using the luciferase-based NAB assay on factor IX activity levels after 
CSL222 dosing, EuroQol (EQ-5D-5L), and international Physical Activity Questionnaire 
(iPAQ). 
Exploratory efficacy objectives will investigate the effect of CSL222 on factor IX protein levels, 
Hemophilia Joint Health Score (HJHS) scores, Work Productivity and Activity Impairment 
Questionnaire (WPAI), Brief Pain Inventory (BPI), Hemophilia Activities List (HAL), and 
Hemophilia Quality of Life Questionnaire for Adults (Hem-A-QoL), subgroup analyses, and will 
estimate ABR as a function of mean factor IX activity (as a “correlation” analysis). 
2.3 Safety Objectives 
The safety objectives include monitoring of AEs, changes in abdominal ultrasound, formation of 
anti-AAV5 antibodies (total immunoglobulin M and immunoglobulin G [IgM and IgG], NABs), 
AAV5 capsid-specific T cell response, formation of anti-factor IX antibodies, formation of factor 
IX inhibitors and recovery, hematology and serum chemistry, shedding of vector DNA in blood 
and semen, inflammatory markers, AST/ALT increase, use of corticosteroids required to 
preserve factor IX activity in the context of AST/ALT increases, and alpha-fetoprotein (AFP). 

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3 TRIAL DESIGN 
3.1 Overall Trial Design 
This is an open-label, single-dose, multi-center, multi-national trial, with a screening period, a 
lead-in phase, a treatment plus a post-treatment follow-up phase, and a long-term follow-up 
phase. Overviews of the trial and its design are presented in Figure 1 and Figure 2. 
At the screening visit (Visit S), subjects will be assessed for eligibility and will be instructed in 
how to record bleeding episodes and use of factor IX replacement therapy in their dedicated 
electronic diary (e-diary). The approximately 4-week period between screening up to the start of 
the lead-in phase (Visit L1) is considered a training period where subjects will record their use of 
factor IX replacement therapy and bleeding episodes in their dedicated e-diary, with the 
Investigator/study nurse reviewing and evaluating any problems with recording of this data with 
the subject. The period between screening and the start of the lead-in phase will also be used to 
wash out subjects from their exogenous factor IX for a pre-defined period of 3 days for 
regular-acting factor IX products and 10 days for extended half-life factor IX products. 
After screening (Visit S), eligible subjects will enter a lead-in phase prior to the start of CSL222 
treatment. 
During the lead-in phase, subjects will record their use of factor IX replacement therapy and 
bleeding episodes in a dedicated e-diary. The length of the lead-in phase is a minimum of 
6 months (26 weeks), ending at or before Visit D. Subjects will remain in the lead-in phase until 
a minimum of 6 months of lead-in data have been collected and it is confirmed that the subject 
still meets all eligibility criteria. The final visit in this phase (Visit L-Final) will occur 
approximately 28 days (± 7 days) prior to the planned date of IMP dose administration (Visit D). 
If the ICF is revised during the lead-in phase with important new information that must be shared 
with the study subjects, the amended ICF will be presented, as required by the Independent 
Ethics Committees (IECs)/Institutional Review Boards (IRBs), for review and consideration by 
the subject, and signed re-consent is to be obtained prior to IMP dose administration. 
During the lead-in phase, visits are planned as follows: 
- 
Visit L1 will occur after eligibility is confirmed, approximately 4 weeks after 
screening. 
- 
Alternating monthly clinic visits and follow-up phone calls until a minimum of 
6 months of lead-in data have been collected and it is confirmed that the subjects still 
meet all eligibility criteria (ie, clinic visits every 2 months; Visit L2 to LX). For 
follow-up phone calls, an email communication is acceptable as an alternative if the 
subject cannot be reached, though reasonable efforts for a phone call should be made. 
The time period between Visit LX and Visit L-Final can be less than 2 months, as 
long as the total lead-in period is a minimum of 26 weeks. 

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- 
The final visit (Visit L-Final) will occur approximately 4 weeks prior to the planned 
date of IMP dose administration (Visit D). 
After the lead-in phase, subjects will receive a single-dose of CSL222 at Visit D and will be 
followed for 1 year (ie, post-treatment follow-up phase; 52 weeks) to evaluate efficacy and 
safety. During the post-treatment follow-up, visits are planned as follows: 
- 
Weekly up to Week 12 (Visit F1 to F12) 
- 
Every month from Month 4 to Month 11 (Visit F13 to F20) 
- 
Final visit at Month 12/Week 52 (Visit F-Final) 
Following the post-treatment follow-up phase, subjects continue into the long-term follow-up for 
an additional 4 years. During the long-term follow-up, visits are planned as follows: 
- 
Every half year (6 months) from 18 to 60 months (4 years; Visit LTF1 to LTF8); 
however, there should be at least quarterly contact (± 2 weeks) between the site staff 
and subjects to monitor for the occurrence of AEs, proper completion of the 
study-specific paper diaries, and proper reporting of factor IX usage and bleeding 
episodes. 
Six months after IMP administration, the first secondary endpoint, endogenous factor IX activity 
at 6 months after CSL222 dosing, will be analyzed once the last subject has achieved 6 months 
after CSL222 treatment. This assessment will be based on clean data and a partially locked 
database. 
Twelve months after IMP administration, the second secondary endpoint, endogenous factor IX 
activity at 12 months after CSL222 dosing, will be analyzed and reported via an interim analysis 
once the last subject has achieved 12 months (52 weeks) after CSL222 treatment. This 
assessment will be based on clean data and a partially locked database. 
Factor IX expression is anticipated to be stable within 6 months post-dose. After 52 weeks 
following stable factor IX expression, the primary assessment of ABR, as well as secondary and 
exploratory efficacy and safety data will be analyzed and reported in a CSR (18 months 
analysis). Data up to that point will be considered locked and will not be changed (with the 
exception of ending dates and outcomes for continuing events and treatments) without explicit 
authorization from the Sponsor. Following the 18 months post-dose assessments, subjects will be 
followed for an additional 3.5 years for evaluation of efficacy parameters and safety. At the end 
of that 3.5-year period, all safety and efficacy data will be reported in a CSR addendum covering 
the entire study duration, including the later 3.5-year period. 
The overall trial participation will be approximately 5.5 years.  
The end of the clinical trial is defined as the point in time the last subject has completed the 
long-term follow-up observation period of 5 years after administration of the IMP. 

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At the end of this trial, subjects will be informed about the option to participate in a separate 
long-term follow-up extension trial (CSL222_3003) to monitor the long-term safety and efficacy 
of CSL222 from approximately 5 to 15 years after treatment. 
3.1.1 Considerations Due to the COVID-19 Pandemic 
Due to the COVID-19 pandemic, adjustments to the visit location/method or schedule may be 
made to accommodate safety concerns and restrictions experienced by individual subjects and 
sites. In all cases, subjects will be kept informed, via the site staff, as much as possible, of 
changes to the study and monitoring plans that could impact them. 
Discontinuation of subjects from the study post-treatment with CSL222 is not considered to be in 
the best interest of the subject, due to the irreversible nature of the IMP. Wherever possible, 
every effort is to be made to have the subject visit the clinic for the study visits according to 
schedule. Should a clinic visit not be possible, options that may be considered include site nurses 
travelling to a subject’s home, local laboratory use, or home nursing services (for certain visits, if 
pre-approved by the Investigator and Sponsor). These options, if used, will be supplemented with 
a phone call or telemedicine/telehealth safety follow-up call. A (temporary) transfer of a subject 
to an alternate clinical trial site may also be considered in order to continue on-site visits, only if 
this does not pose undue burden to the subject and/or “new” site. 
In some instances, it may not be possible to conduct any type of visit at all. Where none of the 
above options are feasible, subject visits may be moved beyond the maximum visit window 
permitted. Such delays will be assessed on a case-by-case basis. Until visits are rescheduled, 
supplemental phone calls or telemedicine/telehealth contact between Investigator/study staff and 
subject are to be arranged. 
Supplemental phone calls or telemedicine/telehealth safety follow-up calls will be used to 
confirm the subject’s status and wellbeing. At these supplemental phone calls, safety information 
should be gathered (ie, AEs, concomitant medication use), subjects should be asked about any 
new unreported bleeds or factor IX consumption and confirm their use of the e-diary or paper 
diaries (as applicable), and there should be continued discussions with the subject on the 
importance of a healthy liver. These discussions will be documented in the source documents. 
All deviations from the study protocol are to be documented, with rationale. If a protocol 
deviation is due to the COVID-19 pandemic, this will be noted. 
3.2 Trial Design Rationale 
In gene therapy it is common practice to provide a single dose of vector via IV infusion. This 
infusion in a previous trial with CSL220 was proven to be safe and effective resulting in 
identification of a clinical dose for CSL220 to proceed to further clinical studies. Although a 
single administration of CSL220 at a dose of 2 × 1013 gc/kg resulted in successful conversion of 

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clinical phenotype to mild in most subjects (Section 1.3.2.2), the desired goal is to achieve higher 
levels of factor IX activity to allow for a more consistent and meaningful clinical response. 
CSL222 is a derivative of CSL220 that produces the hFIX-Padua variant. Based on NHP studies 
with CSL222, as well as data from subjects with the natural Padua mutation, it is expected that, 
compared to its predecessor, CSL222 will lead to a higher level of circulating factor IX activity 
at comparable levels of factor IX protein, thereby increasing the likelihood of alleviating the 
need for exogenous therapy, including on-demand treatment of traumatic bleeds and selective 
prevention of a bleed (eg, because of upcoming physical activity, sports, etc). At 2 × 1013 gc/kg, 
CSL222 is expected to result in mean factor IX activity ranges of 40% of normal, ranging 
between approximately 18 to 76%. Interim analysis data from the Phase IIb trial CSL222_2001 
demonstrated that CSL222 was safe and well tolerated and resulted in mean factor IX activity of 
approximately 30% of normal at 6 weeks after treatment with a dose of 2 × 1013 gc/kg 
(Section 1.3.2.3). 
A dose of 2 × 1013 gc/kg for CSL222 was selected for use in the treatment phase of this study 
based on interim data from CSL222_2001 and the recommendation from the DMC 
(Section 9.12). 
The lead-in phase of the trial is used for assessment of the bleeding episodes occurring during 
standard of care continuous routine factor IX prophylaxis which is part of the primary efficacy 
parameter. Bleeding episodes and factor IX use data are recorded by the subjects in a dedicated 
e-diary after training. The ongoing evaluation of the e-diary data by the Investigator/study nurse 
and subsequent retraining of the subjects, as necessary, is used to ensure adequate data recording 
and compliance. 
This trial is conducted at multiple centers as the prevalence of severe and moderately severe 
hemophilia B subjects is low. 
Due to the nature of the disease in question it is not ethical to perform a placebo-controlled trial 
and no relevant active comparators exist. Based on this, the trial is designed as an open-label and 
uncontrolled trial. 
3.3 Trial Endpoints 
3.3.1 Primary Endpoint 
The primary efficacy endpoint is as follows: 
- 
ABR comparison between CSL222 and prophylaxis for non-inferiority between the 
lead-in phase and the 52 weeks following stable factor IX expression (months 6-18 
post-treatment) 

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3.3.2 Secondary Endpoints 
Secondary efficacy endpoints: 
- 
Endogenous factor IX activity at 6 months after CSL222 dosing 
- 
Endogenous factor IX activity at 12 months after CSL222 dosing 
- 
Endogenous factor IX activity at 18 months after CSL222 dosing 
- 
Annualized consumption of factor IX replacement therapy during the 52 weeks following 
stable factor IX expression (months 6-18 post-treatment), excluding factor IX 
replacement for invasive procedures, compared to the lead-in phase 
- 
Annualized infusion rate of factor IX replacement therapy during the 52 weeks following 
stable factor IX expression (months 6-18 post-treatment), excluding factor IX 
replacement for invasive procedures, compared to the lead-in phase 
- 
Proportion of subjects remaining free of previous continuous routine prophylaxis during 
the 52 weeks following stable factor IX expression (months 6-18 post-treatment) 
- 
Comparison of the percentage of subjects with trough factor IX activity < 12% of normal 
between the lead-in phase and after treatment with CSL222 over the 52 weeks following 
stable factor IX expression (months 6-18 post-treatment) 
- 
ABR comparison between CSL222 and prophylaxis for superiority between the lead-in 
phase and the 52 weeks following stable factor IX expression (months 6-18 
post-treatment) 
- 
Rate of spontaneous bleeding events during the 52 weeks following stable factor IX 
expression (months 6-18 post-treatment) compared to the lead-in phase 
- 
Rate of joint bleeding events during the 52 weeks following stable factor IX expression 
(months 6-18 post-treatment) compared to the lead-in phase 
- 
Estimated ABR – during the 52 weeks following stable factor IX expression 
(months 6-18 post-treatment) – as a function of pre-IMP anti-AAV5 antibody titers using 
the luciferase-based NAB assay (as a “correlation” analysis) 
- 
Correlation of factor IX activity levels during the 52 weeks following stable factor IX 
expression (months 6-18 post-treatment) with pre-IMP anti-AAV5 antibody titers using 
the luciferase-based NAB assay 

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- 
Occurrence of (and resolution of) new target joints during the 52 weeks following stable 
factor IX expression (months 6-18 post-treatment) and resolution of pre-existing target 
joints following CSL222 dosing 
- 
Proportion of subjects with zero bleeds during the 52 weeks following stable factor IX 
expression (months 6-18 post-treatment) 
- 
Patient reported outcome (PRO) questionnaire scores from the iPAQ (total physical 
activity score) during the 12 months following CSL222 dosing compared with the lead-in 
phase 
- 
PRO questionnaire scores from the EQ-5D-5L visual analogue scale (VAS) score during 
the 12 months following CSL222 dosing compared with the lead-in phase 
Exploratory efficacy endpoints: 
- 
Factor IX protein levels during the 18 months following CSL222 dosing  
- 
HJHS scores during the lead-in phase (prophylaxis) and during the 12 months following 
CSL222 dosing 
- 
Other PRO questionnaires: WPAI, BPI, HAL, and Hem-A-QoL questionnaire scores 
during the lead-in phase (prophylaxis) and during the 12 months following CSL222 
dosing 
- 
EQ-5D-5L index scores during the lead-in phase (prophylaxis) and during the 12 months 
following CSL222 dosing 
- 
Estimated ABR as a function of mean factor IX activity (as a “correlation” analysis) over 
the 18 months post-CSL222 treatment follow-up 
- 
Rate of traumatic bleeding events during the 52 weeks following stable factor IX 
expression (months 6-18 post-treatment) compared to the lead-in phase 
- 
Subgroup analyses will be carried out for the following endpoints (the subgroups will be 
identified in the Statistical Analysis Plan [SAP]): 
o Endogenous factor IX activity at Month 18 
o Annualized consumption of factor IX replacement therapy during the 52 weeks 
following stable factor IX expression (months 6-18 post-treatment), excluding 
replacement for invasive procedures, compared to the lead-in phase 
o Annualized infusion rate of factor IX replacement therapy during the 52 weeks 
following stable factor IX expression (months 6-18 post-treatment), excluding 
replacement for invasive procedures, compared to the lead-in phase 

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o ABR comparison between CSL222 during the 52 weeks following stable factor 
IX expression (months 6-18 post-treatment) and factor IX prophylaxis (during the 
lead-in phase) 
o Comparison of the percentage of subjects with trough factor IX activity < 12% of 
normal between the lead-in phase and after treatment with CSL222 during the 
52 weeks following stable factor IX expression (months 6-18 post-treatment) 
o Proportion of subjects remaining free of previous prescribed continuous routine 
prophylaxis during the 52 weeks following stable factor IX expression 
(months 6-18 post-treatment) 
All efficacy endpoints will be analyzed as exploratory endpoints as part of the CSR addendum 
written at the end of the trial: 
- 
Endogenous factor IX activity at 2, 3, 4, and 5 years after CSL222 dosing 
- 
ABR comparison between CSL222 and prophylaxis for non-inferiority between the 
2-year, 3-year, 4-year, and 5-year post-treatment (CSL222) follow-up and the lead-in 
phase 
- 
Annualized consumption of factor IX replacement therapy during the 2-year, 3-year, 
4-year, and 5-year post-treatment follow-up, excluding factor IX replacement for invasive 
procedures, compared to the lead-in phase 
- 
Annualized infusion rate of factor IX replacement therapy during the 2-year, 3-year, 
4-year, and 5-year post-treatment follow-up, excluding factor IX replacement for invasive 
procedures, compared to the lead-in phase 
- 
Proportion of subjects remaining free of previous continuous routine prophylaxis during 
the 2-year, 3-year, 4-year, and 5-year post-treatment follow-up 
- 
Comparison of the percentage of subjects with trough factor IX activity < 12% of normal 
between the lead-in phase and after treatment with CSL222 at 2, 3, 4, and 5 years after 
CSL222 dosing 
- 
ABR comparison between CSL222 and prophylaxis for superiority between the lead-in 
phase and the 2-year, 3-year, 4-year, and 5-year post-treatment (CSL222) follow-up 
- 
Rate of spontaneous bleeding events during the 2-year, 3-year, 4-year, and 5-year 
post-treatment (CSL222) follow-up compared to the lead-in phase 
- 
Rate of joint bleeding events during the 2-year, 3-year, 4-year, and 5-year post-treatment 
(CSL222) post-treatment follow-up compared to the lead-in phase 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
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- 
Estimated ABR – at 2 years, 3 years, 4 years, and 5 years post-CSL222 treatment – as a 
function of pre-IMP anti-AAV5 antibody titers using the luciferase-based NAB assay (as 
a “correlation” analysis) 
- 
Correlation of factor IX activity levels at 2 years, 3 years, 4 years, and 5 years 
post-CSL222 treatment with pre-IMP anti-AAV5 antibody titers using the 
luciferase-based NAB assay 
- 
Occurrence and resolution of target joints during the 2 years, 3 years, 4 years, and 5 years 
following CSL222 dosing 
- 
Proportion of subjects with zero bleeds in the 2 years, 3 years, 4 years, and 5 years 
post-treatment (CSL222) follow-up 
- 
PRO questionnaire scores from the iPAQ at 2 years, 3 years, 4 years, and 5 years 
post-CSL222 treatment compared to the lead-in phase 
- 
PRO questionnaire scores from the EQ-5D-5L at 2 years, 3 years, 4 years, and 5 years 
post-CSL222 treatment compared to the lead-in phase 
- 
Factor IX protein levels during the 2 years, 3 years, 4 years, and 5 years following 
CSL222 dosing  
- 
HJHS scores during the lead-in phase (prophylaxis) and during the 2 years, 3 years, 
4 years, and 5 years following CSL222 dosing 
- 
Other PRO questionnaires: WPAI, BPI, HAL, and Hem-A-QoL questionnaires during the 
lead-in phase (prophylaxis) and during the 2 years, 3 years, 4 years, and 5 years following 
CSL222 dosing 
- 
Estimated ABRs over time as a function of mean factor IX activity (as a “correlation” 
analysis) over the 2 years, 3 years, 4 years, and 5 years post-CSL222 treatment follow-up 
- 
Rate of traumatic bleeding events during the 2 years, 3 years, 4 years, and 5 years 
post-treatment follow-up compared to the lead-in phase 
Secondary safety endpoints  
- AEs 
- Changes in abdominal ultrasound 
- Anti-AAV5 antibodies (total [IgM and IgG], NABs) 
- AAV5 capsid-specific T cells  

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- Anti-factor IX antibodies 
- Factor IX inhibitors and recovery 
- Hematology and serum chemistry parameters 
- ALT/AST levels, and corticosteroid use for ALT/AST increases 
- Vector DNA in blood and semen  
- Inflammatory markers: IL-1β, IL-2, IL-6, IFNγ, MCP-1 
- AFP 
3.3.3 Sub-study Endpoints 
- Patient Reported Outcomes, Burdens, and Experiences (PROBE) summary scores and 
individual item responses. 
- MSKUS Sub-study Endpoints 
o Joint Tissue Activity and Damage Exam (J.A.D.E.) scores 
3.4 Sample Size 
The study sample size is constrained by the non-inferiority analysis of the primary endpoint, 
ABR. Via simulation of ABR under a negative binomial distribution with a yearly rate of 
2.4 events for lead-in and 1.9 for post-treatment, with a Pearson correlation of 0.05 for the 
number of events between the 2 periods, and with a common negative binomial dispersion 
parameter of 1.5, a sample size of N = 50 will demonstrate non-inferiority with a non-inferiority 
margin of 1.8 and a power of 82.0%. Therefore, the study should consist of at least 50 analyzable 
subjects. 
Refer to Section 9.11 for further information on sample size justification. 
3.5 Sites and Regions 
It is planned to conduct this trial in approximately 50 sites in the United States of America 
(USA), EU, and the United Kingdom (UK). 

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4 TRIAL POPULATION 
Subjects will be adult males with severe or moderately severe hemophilia B. 
4.1 Inclusion Criteria 
The subject cannot be enrolled in the trial before all of the following inclusion criteria are met: 
 Male 
 Age ≥ 18 years 
 Subjects with congenital hemophilia B with known severe or moderately severe factor IX 
deficiency (≤ 2% of normal circulating factor IX) for which the subject is on continuous 
routine factor IX prophylaxis* 
 > 150 previous exposure days of treatment with factor IX protein 
 Have been on stable prophylaxis for at least 2 months prior to screening 
 Have demonstrated capability to independently, accurately and in a timely manner 
complete the diary during the lead-in phase as judged by the Investigator 
 Acceptance to use a condom during sexual intercourse in the period from IMP 
administration until AAV5 has been cleared from semen, as evidenced by the central 
laboratory from negative analysis results for at least 3 consecutively collected semen 
samples (this criterion is applicable also for subjects who are surgically sterilized) 
 Able to provide informed consent following receipt of verbal and written information 
about the trial. 
* Continuous routine prophylaxis is defined as the intent of treating with an a priori defined 
frequency of infusions (eg, twice weekly, once every 2 weeks, etc) as documented in the medical 
records. 
4.2 Exclusion Criteria 
Subjects are excluded from the trial if any of the following exclusion criteria (including local and 
central laboratory test results, as specified) are met:  
 History of factor IX inhibitors 
 Positive factor IX inhibitor test at screening and Visit L-Final (based on local laboratory 
results) 
 Screening and Visit L-Final laboratory values (based on central laboratory results): 
a. ALT > 2 times upper normal limit (ie, upper limit of normal; ULN) 
b.  AST > 2 times ULN 
c. Total bilirubin > 2 times ULN (except if caused by Gilbert disease) 
d. Alkaline phosphatase (ALP) > 2 times ULN 
e. Creatinine > 2 times ULN 

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 Positive human immunodeficiency virus (HIV) serological test at screening and 
Visit L-Final, not controlled with anti-viral therapy as shown by CD4+ counts ≤ 200/μL 
(based on central laboratory results) 
 Hepatitis B or C infection with the following criteria present at screening: 
a. Currently receiving antiviral therapy for this/these infection(s) 
and/or 
b. Positive for any of the following (based on central laboratory results): 
i. 
Hepatitis B surface antigen (HBsAg), except if in the opinion of the Investigator 
this is due to a previous Hepatitis B vaccination rather than active Hepatitis B 
infection 
ii. 
Hepatitis B virus deoxyribonucleic acid (HBV DNA) 
iii. 
Hepatitis C virus ribonucleic acid (HCV RNA) 
 Known coagulation disorder other than hemophilia B 
 Thrombocytopenia, defined as a platelet count below 50 × 109/L, at screening and 
Visit L-Final (based on central laboratory results) 
 Known severe infection or any other significant concurrent, uncontrolled medical 
condition including, but not limited to, renal, hepatic, cardiovascular, hematological, 
gastrointestinal, endocrine, pulmonary, neurological, cerebral or psychiatric disease, 
alcoholism, drug dependency or any other psychological disorder evaluated by the 
Investigator to interfere with adherence to the protocol procedures or with the degree of 
tolerance to the IMP 
 Known significant medical condition that may significantly impact the intended 
transduction of the vector and/or expression and activity of the protein, including but not 
limited to: 
a. Disseminated intravascular coagulation 
b. Accelerated fibrinolysis 
c. Advanced liver fibrosis (suggestive of or equal to METAVIR Stage 3 disease; eg, a 
FibroScan™ score of ≥ 9 kPa is considered equivalent) 
 Known history of an allergic reaction or anaphylaxis to factor IX products 
 Known history of allergy to corticosteroids 
 Known uncontrolled allergic conditions or allergy/hypersensitivity to any component of 
the IMP excipients 
 Known medical condition that would require chronic administration of steroids 
 Previous gene therapy treatment 
 Receipt of an experimental agent within 60 days prior to screening 
 Current participation or anticipated participation within 1 year after IMP administration 
in this trial in any other interventional clinical trial involving drugs or devices. 

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4.3 Reproductive Potential 
Male subjects who participate in this trial accept to use a condom during sexual intercourse in the 
period from IMP administration until AAV5 has been cleared from semen, as evidenced by the 
central laboratory from negative analysis results for at least 3 consecutively collected semen 
samples (this criterion is applicable also for subjects who are surgically sterilized). 
Subjects are being asked to inform their partner of their participation in this trial, as well as the 
importance of contraception use to limit the reproductive potential in the period from IMP 
administration until AAV5 has been cleared from the semen. 
4.4 Restrictions 
There is 1 restriction associated with participation in this trial, which is related to reproduction 
and described in Section 4.3. 
4.5 Withdrawal of Subject from Therapy or Assessment 
A subject may withdraw from the trial at any time, for any reason, without prejudice to their 
future medical care by his/her physician or at the institution. The Investigator or Sponsor may 
withdraw the subject at any time if it is not in the best interest of the subject to continue 
participation. Since this is a gene therapy trial in which the IMP is administered to human 
subjects as a one-time only dose, the Investigator should make all reasonable attempts to 
maintain the subjects in the trial after IMP administration to allow long-term follow-up on safety. 
Where a subject is withdrawn from the trial at his own request or based on a decision of the 
Investigator, the safety follow-up should be maintained, conditional to the consent of the subject. 
The safety follow-up will include periodic review (approximately every 6 months) of medical 
records to gather information obtained during routine visits from the subject with his treating 
physician for the time until 5 years post-IMP administration. Information on AEs, SAEs, 
concomitant medication use (including factor IX usage), and imaging and laboratory assessments 
will be collected, as available, and recorded on the electronic case report form (eCRF). If a 
subject is to withdraw from the trial, the Investigator should make all reasonable attempts to have 
the subject sign the separate ICF in order to maintain the long-term safety follow-up. 
Subjects who withdraw from the trial after being dosed with CSL222 will be requested to 
complete the same final evaluations (Section 6.1.4.1) as subjects completing the trial according 
to the protocol, particularly safety evaluations in the subject’s interest so that data can be 
recorded in the same way as for subjects who completed the trial. Comments (spontaneous or 
elicited) or complaints made by the subject must be recorded in the source documents. The 
reason for (if given) and date of withdrawal, must be recorded on the eCRF and source 
documents. Subjects will be offered long-term follow-up in a separate extension trial 
(CSL222_3003) from approximately 5 to 15 years after treatment. 

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Subjects who withdraw from the trial after enrolling in the Lead-in Phase but who are not dosed 
will be required to return their e-diary device and will not be requested to complete any final 
evaluations. 
Sufficient subjects will be enrolled to ensure a minimum of 50 subjects in the PP population. It is 
estimated that at least 56 subjects on continuous routine prophylaxis may be enrolled to ensure 
there are sufficient subjects to achieve this goal. 
4.5.1 Reasons for Discontinuation 
The reasons for discontinuation from this gene therapy trial include: 
• 
AE 
• 
Withdrawal by principal Investigator 
• 
Withdrawal by subject 
• 
Lost to follow-up 
4.5.2 Subjects “Lost to Follow-up” Prior to Last Scheduled Visit 
At least 3 documented attempts must be made to contact any subject lost to follow-up at any time 
point prior to the last scheduled contact (office visit or telephone contact). One of these 
documented attempts must include a written communication sent to the subject’s last known 
address via courier or mail (with an acknowledgement of receipt request) asking that they return 
the e-diary device (if applicable) and return to the site for final safety evaluations. 

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5 TRIAL TREATMENT 
5.1 Treatment(s) Administered 
5.1.1 Investigational Medicinal Product 
The IMP is identified as AAV5-hFIXco-Padua (hereafter referred as CSL222; etranacogene 
dezaparvovec). CSL222 is a recombinant adeno-associated viral vector of serotype 5 (AAV5) 
containing the Padua variant of a codon-optimized human factor IX cDNA under the control of a 
liver-specific promoter. The pharmaceutical form of CSL222 is a solution for IV infusion. 
Subjects will receive a single IV infusion of 2 × 1013 gc/kg CSL222. 
5.1.2 Non-Investigational Medicinal Product 
The reference therapy is the prophylaxis factor IX replacement therapy used during the lead-in 
phase prior to treatment with CSL222. 
5.2 Identity of Investigational Medicinal Product 
CSL222 is formulated as a sterile solution at a concentration of approximately 1 × 1013 gc/mL in 
Phosphate Buffer Saline pH 7.2 with 5% (w/w) sucrose and 0.02% (v/v) polysorbate-20. The 
components of the CSL222 drug product are given in Table 6. 
CSL222 will be supplied in 10 R clear glass type I vials filled with approximately 10 mL of IMP. 
Each vial will contain an extractable volume of at least 10 mL. 
Additional information is provided in the Investigator’s Brochure. 
Table 6 
Components of CSL222 Drug Product 
Component 
Quantity per vial a 
Function 
AAV5-hFIXco-Padua 
10 × 1013 gc 
Active ingredient 
Sucrose 
500 mg 
Stabilizer 
Polysorbate-20 
2.0 µL 
Surfactant 
Potassium chloride  
2.0 mg 
Buffer, tonicity 
Potassium dihydrogen phosphate  
2.0 mg 
Sodium chloride 
80.0 mg 
Sodium hydrogen phosphate  
11.4 mg 
Water for injections  
qs a 10 mL 
gc: genome copies; qs: sufficient quantity 
a. 
The vials are filled with approximately 10 mL drug product. The numbers presented in the table are based on 10 mL. 
 

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5.3 Dosing and Administration 
CSL222 will be administered at a dose of 2 × 1013 gc/kg as a one-time infusion in a peripheral 
vein. The subjects will be monitored for tolerance to the IMP and detection of immediate AEs 
for 3 hours or 8 hours (only subjects in Germany) after dosing.  
Detailed instructions for IMP handling eg, receipt, storage, preparation, administration, cleaning, 
destruction, and the recording of these critical activities will be described in the IMP Handling 
Manual. 
5.4 Randomization and Blinding 
Not applicable, as this is an open-label trial with 1 treatment arm. 
5.5 Labeling, Packaging, Storage, and Handling 
All medication used in this trial will be prepared and labeled according to the rules of Good 
Manufacturing Practice, International Council for Harmonisation (ICH)-Good Clinical Practice 
(GCP) (E6[R2]) and local regulatory requirements. Further details on IMP labeling, packaging 
and handling, eg, receipt, storage, preparation, administration, cleaning, destruction, 
documentation etc, will be described in the IMP Handling Manual. 
5.6 Prior and Concomitant Medication/Therapy 
5.6.1 Prior Medication/Therapy 
Prior medication/therapy includes medication/therapy (including herbal treatments, vitamins, 
non-pharmacological treatment such as psychotherapy as appropriate) received within 30 days of 
and discontinued prior to the date of screening. Prior medication/therapy information must be 
recorded on the appropriate eCRF page. 
For this trial, it is not allowed to have received an experimental agent within 60 days prior to 
screening. In addition, use of previous gene therapy is not allowed. 
5.6.2 Concomitant Medication/Therapy 
Concomitant medication/therapy is defined as any medication/therapy being continued by the 
subject post IMP administration (Visit D), and any new medication/therapy received during the 
trial. 
Concomitant treatment taken as of the date of IMP administration must be recorded on the 
appropriate eCRF page. 

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The following treatments will not be allowed during trial participation: 
- 
Continuous routine factor IX prophylaxis post-dose if a subject’s endogenous factor 
IX activity result is above 5% 
- 
Treatment in another interventional clinical trial involving drugs or devices for 1 year 
following IMP administration in this trial 
- 
Another gene therapy treatment  
- 
Chronic administration of steroids (oral and/or inhaled) 
For any known hepatotoxic medications, other alternatives should be considered. The 
Investigator is expected to review the concomitant medications on an ongoing basis for these 
types of medications. Where possible, subjects should be taken off any known hepatotoxic drugs 
before Visit D. A searchable, comprehensive list of drugs ranked by Drug Induced Liver Injury 
(DILI) concern (Food and Drug Administration [FDA] Drug Induced Liver Injury Rank 
[DILIrank] dataset) is available from the following site: 
https://www.fda.gov/ScienceResearch/BioinformaticsTools/LiverToxicityKnowledgeBase/ucm6
04985.htm. 
Apart from the above listed treatments, no protocol restrictions will apply with respect to 
concomitant medications. 
Subjects are permitted to continue to administer their continuous routine factor IX treatment on 
the day of dosing (after the pre-IMP assessments are completed) and continue their continuous 
routine factor IX treatment in the first weeks after dosing to provide sufficient factor IX coverage 
for the initial days post-treatment. During the post-treatment follow-up visits, endogenous factor 
IX activity will be assessed. If the endogenous factor IX activity result is ≥ 5%, continuous 
routine factor IX prophylaxis will be discontinued, and further management will be based on 
Investigator’s clinical judgement and subject preference. Continuation or re-initiation of 
continuous routine factor IX prophylaxis may be considered if the endogenous factor IX activity 
is between 2 and 5% in at least 2 consecutive laboratory measurements, based on the 
Investigator’s clinical judgement and subject preference. If endogenous factor IX activity is 
< 2%, continuous routine prophylaxis must be continued or reinstated. Additional on-demand 
and/or intermittent prophylactic factor IX treatment may be given after treatment with CSL222, 
if considered necessary. 
Factor IX infusions are not recommended for subjects with factor IX activity in the 
non-hemophilic (≥ 40% of normal) range especially in subjects with a confirmed COVID-19 
infection, as increased thrombogenic risk is a known complication of COVID-19. Subjects with 
factor IX activity in the non-hemophilic range post-treatment with CSL222 and infected with 
COVID-19 may potentially be at the same risk of thrombosis as subjects without hemophilia; 
antithrombotic therapy for these subjects should be considered under the same guidelines 
recommended for those without hemophilia. 

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5.6.3 Guidelines for Use of Factor IX for Subjects Undergoing Major Surgery 
Replacement of factor IX for subjects undergoing major surgery in this trial will be according to 
established guideline (Srivastava et al, 2013) in terms of factor IX activity level pre- and 
post-surgical procedure. The target factor IX activity level pre- and post-major surgery, 
regardless of whether the regular or extended half-life replacement is administered as per World 
Federation of Hemophilia, is as follows: 
 
Factor IX Activity Level 
Pre-operative: 
60 to 80% 
Post-operative: 
40 to 60% Day 1 to 3 
 
30 to 50% Day 4 to 6 
 
20 to 40% Day 7 to 14 
 
For minor surgery, use of factor IX is up to the Investigator but should be discussed with the 
medical monitor. 
Factor IX infusions are not recommended for subjects with factor IX activity in the 
non-hemophilic (≥ 40% of normal) range especially in subjects with a confirmed COVID-19 
infection, as increased thrombogenic risk is a known complication of COVID-19. Subjects with 
factor IX activity in the non-hemophilic range post-treatment with CSL222 and infected with 
COVID-19 may potentially be at the same risk of thrombosis as subjects without hemophilia; 
antithrombotic therapy for these subjects should be considered under the same guidelines 
recommended for those without hemophilia. 
5.6.4 Guidelines for Transaminase Elevations 
Transaminase levels will be monitored based on the site’s local laboratory results and central 
laboratory results, with local laboratory analysis results arranged, if possible, to be provided on 
the same day or the day after the blood sample is collected to allow for rapid detection of any 
elevations in transaminase levels. 
For ALT level increments of at least 2-fold baseline (ie, Visit D, pre-IMP) and/or > ULN, by 
local or central laboratories, the Investigator should contact the Medpace and/or CSL Behring 
Medical Directors to discuss a clinical management plan on a case-by-case basis, including 
potential re-tests and/or initiation of corticosteroid treatment. In case of AST level increments 
> ULN, the Investigator should contact the Medpace and/or CSL Behring Medical Directors and 
a similar discussion should take place.  
Investigators should assess potential causes of a transaminase elevation, to rule out if the 
elevation is due to intense exercise, alcohol consumption, or use of concomitant medications. 
Additional laboratory assessments including creatine kinase assessment and a viral panel are 
recommended as needed. 

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See Table 7 for a recommended approach to prednisolone treatment. Medications equivalent to 
prednisolone may also be used. A combined immunosuppressant regimen or the use of other 
products can also be considered in case of prednisolone treatment failure or contraindication. 
Corticosteroid tapering should be discussed among the Investigator and Medpace and/or 
CSL Behring Medical Directors based on changes in and normalization of transaminase levels. 
Investigators should monitor subjects for steroid-related AEs. If use of high dose 
prednisolone/prednisone is prolonged, blood pressure and glucose levels should be monitored at 
each clinic visit, or more frequently if needed, and Investigators should consider starting subjects 
on vitamin D, a proton pump inhibitor, and/or Pneumocystis jiroveci prophylaxis therapy. 
Subjects who are placed on corticosteroid treatment should be closely monitored for potential 
COVID-19 infection. Where possible and as per site guidelines and at the discretion of the 
Investigator, subjects should be tested for COVID-19 at the time of initiating corticosteroid 
treatment. Those on corticosteroid treatment who are positive for COVID-19 might be 
considered for more rapid tapering than outlined in Table 7; steroid tapering should be discussed 
among the Investigator and Medpace and/or CSL Behring Medical Directors. 
Table 7 
Use of Prednisolone for the Treatment of Transaminase Increase 
Timeline 
Prednisolone dose (mg/day) 
Week 1 
60 
Week 2 
40 
Week 3 
30 
Week 4 
30 
Maintenance until transaminase level returns to baseline level (Visit 
D, pre-IMP) 
20 
After pre-IMP level has been reached 
Reduce daily dose by 5 mg/week 
5.7 Treatment Compliance and Drug Accountability 
Investigators will be provided with a subject pack containing sufficient vials of the IMP to 
prepare and administer the required dose for each subject. The Investigator or designee will 
acknowledge receipt of the subject pack by documenting date of receipt, shipment content, and 
condition. Accurate records of all IMP prepared, administered, returned, and/or destroyed must 
be maintained as detailed further in this section as well as in the IMP Handling Manual. 
Investigators will be responsible for implementing a system for subject and product traceability 
at the clinical site. That system should contain sufficient detail to allow linking of each vial 
delivered to the Investigator to the subject receiving it and vice versa. 
The Investigator has overall responsibility for preparing and administering the IMP. Where 
permissible, tasks may be delegated to a qualified designee (eg, a pharmacist) who is adequately 
trained in the protocol and procedures as described in the IMP Handling Manual and who works 
under the supervision of the Investigator. This delegation must be documented in the applicable 
trial delegation of authority form. 

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The Investigator or his/her designee will administer the IMP only to subjects included in this 
trial, for whom it is confirmed that they are eligible for dosing, following the procedures set out 
in the trial protocol and the IMP Handling Manual. Each subject will be given only the IMP 
carrying his treatment assignment. All dispensing will be documented on the eCRFs and/or other 
IMP records. 
The Sponsor or its representatives must be permitted access to review the supplies storage and 
distribution procedures and records. 
Based on entries in the Interactive Web Response System (IWRS) and drug accountability forms, 
it must be possible to reconcile IMPs delivered with those used and destroyed if unused. All 
IMPs must be accounted for and all discrepancies must be investigated and documented to the 
Sponsor’s satisfaction. 

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6 TRIAL SCHEDULE AND ASSESSMENTS 
6.1 Trial Schedule 
For details on the timing and frequency of the assessments and testing during screening (Visit S), 
lead-in (Visit L1 to L-Final), and Treatment (Visit D) + post-treatment follow-up (Visit F1 
[Week 1] to F-Final [Week 52/Month 12]) refer to the flow charts in Table 1 and Table 2, and for 
the long-term follow-up (Visit LTF1 [Month 18] to LTF8 [Month 60]) refer to Table 3 and 
Table 4. 
Throughout the study, it will be the aim to draw blood samples at those time points when the 
subject’s factor IX activity level is expected to be at its trough. See Section 6.2.2.3 for further 
details. 
6.1.1 Screening (Visit S) 
Informed consent must be obtained from each subject prior to any of the trial procedures being 
performed (Section 10.3.1). 
At this visit, subjects will be asked to complete the PRO questionnaires and the HJHS will be 
assessed. It is recommended that each subject should complete the PRO questionnaires, 
including PROBE (if applicable), after ICF signature, but before other (trial-specific) 
assessments are performed. Screening assessments will also include medical history, vital signs, 
physical examination (including height and weight), MSKUS (if applicable), and blood 
sampling. With prior approval from the Sponsor, screening procedures can occur during the 
duration of the screening period. 
A FibroScan (or suitable alternative) will be performed with liver fibrosis scores collected during 
the assessment. If possible, steatosis (Controlled Attenuation Parameter [CAP]) scores should 
also be collected during the assessment. The FibroScan should preferably be done at the 
screening visit or at an alternative time point, however at Visit L-Final at the latest. If a 
Fibroscan was performed in the year prior to screening for which fibrosis score is available or if 
liver biopsy has been performed within the 2 years prior to screening and fibrosis grade was 
documented, a FibroScan is not necessary. 
At this visit, subjects will receive their e-diary and the Investigator/study nurse will train them in 
recording of the bleeding episodes and use of factor IX replacement therapy. From screening 
onwards, subjects will record their use of factor IX replacement therapy and bleeding episodes in 
the dedicated e-diary. e-diary data will be reviewed on a continuous basis by the 
Investigator/study nurse. The approximately 4-week period between the screening visit (Visit S) 
up to the start of the lead-in phase (Visit L1) is considered a training period, after which the 
Investigator/study nurse will review and evaluate any problems with recording of e-diary data 

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with the subject. The e-diary training can be repeated at any time during the trial as considered 
necessary by Investigator/study nurse. 
Eligibility according to the trial in- and exclusion criteria will be evaluated at screening and 
during the period up to start of the lead-in phase. For a description of the in- and exclusion 
criteria, refer to Section 4.1 and Section 4.2. 
The overall eligibility will be determined once all screening values and results of other required 
procedures are available. Subjects who fail to meet inclusion criteria and/or meet at least one of 
the exclusion criteria and did not receive CSL222 are defined as a screen failure. 
Subjects who meet an exclusion criterion or fail to meet an inclusion criterion (screen failures) 
may only be re-evaluated for participation in the trial after consultation with, and agreement 
from, the Sponsor. 
Separate optional informed consents will be taken for blood sampling for future research and 
factor IX gene sequencing analyses. Factor IX gene sequence analyses will be performed for all 
subjects that provide consent, even if they already have factor IX gene mutation information 
available. If the subject provides consent for one or both ICFs, the respective blood samples will 
be taken during the screening visit. 
Separate optional informed consents are to be taken for the PROBE sub-study, and for the 
MSKUS sub-study. Assessments will only be performed if the site is participating in the 
sub-study and the subject has provided consent for the sub-study. 
The use of concomitant medication and occurrence of AEs will be monitored throughout the trial 
on an ongoing basis. 
From screening onwards, the Investigator or designee will have regular discussions with the 
subject regarding the importance of a healthy liver before and after receiving a liver directed 
gene therapy, and factors that might impact liver health (including acetaminophen and alcohol 
intake). It is recommended that the acetaminophen total daily dose per subject be limited to 
≤ 2 g/day. It is also recommended that subjects on the study should not consume > 20 g of 
alcohol per day. It is recommended that the daily alcohol limit in grams be adhered to most 
strictly during the first 12 weeks post-IMP. The following stated limit of amount/frequency may 
help guide the study team to counsel subjects regarding alcohol use in a similar manner across 
the duration of the trial: 
- 
In the US, 1 “standard” drink (or a “unit” of alcohol) contains roughly 14 g of pure 
alcohol, which is found in 12 ounces of regular beer, 5 ounces of wine or 1.5 ounces 
of distilled spirits (Source: National Institute of Alcohol Abuse and Alcoholism 
[NIAAA]). 

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In Europe, alcohol content in a “standard drink” measure differs between countries. On average, 
they contain between 8 and 13 g of ethanol across Europe. It is recommended that one visits their 
national consumer information website(s) for further information if necessary (Source: 
https://responsibledrinking.eu/what-is-a-standard-drink-of-alcohol/). 
While it is recommended that the daily alcohol limit in grams be adhered to most strictly during 
the first 12 weeks post-IMP, the importance of abstaining from binge-drinking at any point 
post-IMP administration should be reinforced at every visit. 
6.1.2 Lead-in Phase (Visit L1 to L-Final) 
During the lead-in phase, visits are planned as follows: 
- 
Visit L1 will occur after eligibility is confirmed, approximately 4 weeks after 
screening. 
- 
Alternating monthly clinic visits and follow-up phone calls until a minimum of 
6 months of lead-in data have been collected and it is confirmed that the subjects still 
meet all eligibility criteria (ie, clinic visits every 2 months; Visit L2 to LX). For 
follow-up phone calls, an email communication is acceptable as an alternative if the 
subject cannot be reached, though reasonable efforts for a phone call should be made. 
The time period between Visit LX and Visit L-Final can be less than 2 months, as 
long as the total lead-in period is a minimum of 26 weeks. 
- 
The final visit (Visit L-Final) will occur approximately 4 weeks prior to the planned 
date of IMP dose administration (Visit D). 
The length of the lead-in phase is a minimum of 6 months (26 weeks), ending at or before 
Visit D. Subjects will remain in the lead-in phase until a minimum of 6 months of lead-in data 
have been collected and it is confirmed that the subjects still meet all eligibility criteria, with the 
final visit in this phase (Visit L-Final) occurring approximately 28 days (± 7 days) prior to the 
planned date of IMP dose administration (Visit D). 
At Visit L1, blood samples for assessment of factor IX activity and factor IX protein 
concentration will be taken. Prior to this visit, subjects must have undergone a wash out period 
from their usual factor IX product/dose. The wash out period will be 3 days for regular-acting 
factor IX products and 10 days for extended half-life factor IX products. 
During the lead-in phase, subjects will record their use of prophylactic factor IX replacement 
therapy and bleeding episodes in the e-diary. E-diary data will be reviewed on a continuous basis 
by the Investigator/study nurse, with alternating monthly clinic visits and follow-up phone calls 
(in line with the trial schedule and with retraining by phone as needed). For follow-up phone 
calls, an email communication is acceptable as an alternative if the subject cannot be reached, 
though reasonable efforts for a phone call should be made. 

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In addition to the subjects’ reporting of bleeding episodes in the e-diary, the Investigator or 
designee will assess each bleeding episode, by describing the reported bleeding episode as soon 
as possible but at least within 72 hours after it has been reported by the subject. In case the 
information provided in the e-diary is not sufficient to assess the bleeding episode, the subject 
must be called and/or visit the site. 
At the clinic visits during this lead-in phase (occurring every 2 months), blood samples will be 
taken for assessment of factor IX activity, transaminases, and AAV5 antibodies. In addition, the 
regular discussions with the subject regarding the importance of a healthy liver before and after 
receiving a liver directed gene therapy, and factors that might impact liver health (including 
acetaminophen and alcohol intake), will continue. 
Subjects will be asked to complete the PRO questionnaires at Visit L3, including PROBE (if 
applicable). 
If the ICF is revised during the lead-in phase with important new information that must be shared 
with the study subjects, the amended ICF will be presented, as required by the IRB/IEC, for 
review and consideration by the subject, and signed re-consent is to be obtained at Visit L-Final 
at the latest. 
During Visit L-Final, the subject’s eligibility will be re-evaluated based on assessments during 
the lead-in period and at Visit L-Final (for an overview of the inclusion and exclusion criteria see 
Section 4.1 and Section 4.2). If a subject, who was previously considered eligible, no longer 
meets the trial inclusion criteria, the subject can be re-evaluated as described in Section 6.1.1. 
The laboratory values obtained at this visit will be used to determine eligibility for dosing and 
continued participation in the trial. The baseline abdominal ultrasound should be done at 
Visit L-Final at the latest. 
At Visit L-Final, it is recommended that each subject should complete the PRO questionnaires, 
including PROBE (if applicable), prior to the interview by the Investigator and/or study nurse 
and any other trial related procedures. Other assessments at this visit include the MSKUS (if 
applicable), joint health score (HJHS), physical examination (including weight), and vital signs 
evaluation. Additionally, the factor IX recovery assessment is done (Section 6.2.3.7). 
If a subject is travelling to a different site for Visit D, the treatment card should be handed out at 
the L-Final visit and the subject should be instructed to bring it with him to Visit D. These 
subjects may also provide their semen sample at Visit L-Final instead of Visit D. 

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6.1.3 IMP Dose Administration (Visit D) 
6.1.3.1 Pre-IMP Dose Administration (Baseline, Day 1) 
Prior to administration of CSL222, the Investigator should ensure subject’s eligibility 
(Section 4.1 and Section 4.2). Laboratory results from Visit L-Final will be used to confirm 
eligibility for dosing and continued participation in the trial. If a subject, who was previously 
considered eligible, no longer meets the trial inclusion criteria, the subject can be re-evaluated 
once, as described in Section 6.1.1. 
At this visit, vital sign measurements will be taken, and a physical examination will be 
performed. Furthermore, baseline blood and semen samples will be collected for efficacy and 
safety laboratory parameters, serum chemistry, and hematology as detailed in Table 2. Also, for 
subjects who signed the optional ICF, the sample for future research is taken. 
6.1.3.2 IMP Dose Administration 
Subjects will receive a single infusion of CSL222 according to the procedures described in 
Section 5.3 and in the IMP Handling Manual. 
6.1.3.3 Post-IMP Dose Administration  
Three hours or 8 hours (only subjects in Germany) after completion of the IMP infusion, vital 
signs are measured, and blood samples are taken for C-reactive protein (CRP) measurement and 
vector genome detection. The subject may leave the clinic after all Visit D, post-IMP 
assessments have been performed, and the subject has received his subject treatment card. 
Subjects who travelled to a different site for Visit D should have received their treatment card at 
the L-Final visit and brought it with them to Visit D. 
Subjects are permitted to continue their continuous routine factor IX treatment post-IMP and in 
the first weeks after dosing to provide sufficient factor IX coverage for the initial days 
post-treatment. 
6.1.4 Post-Treatment Follow-up (Visit F1 to F-Final [Week 1 to Week 52/Month 12]) 
Subjects are followed for a total duration of 52 weeks, with visits weekly for the first 12 weeks, 
(Visits F1 [Week 1] to F12 [Week 12]), and monthly from Month 4 to Month 12 (Visits F13 
[Month 4] to F-Final [Month 12]). With agreement from the Investigator and Sponsor, visits 
during the post-treatment follow-up period (from Week 1 up until Week 52) that do not include 
physical examination and/or PRO questionnaires may be performed at the subject’s home by an 
appropriately qualified and trained nurse. Each home nursing visit is expected to be 
supplemented by a phone call from the Investigator or designee to the subject to discuss AEs, 
concomitant medications, and e-diary compliance. Options for how visits may occur to 
accommodate safety concerns and restrictions due to COVID-19 are described in Section 3.1.1.  

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During the post-treatment follow-up phase, subjects will continue to record their use of factor IX 
replacement therapy and bleeding episodes in the e-diary, following the same principles as 
during the lead-in phase, as described in Section 6.1.2. The Investigator or designee will assess 
each bleeding episode, by describing the reported bleeding episode as soon as possible but at 
least within 72 hours after it has been reported by the subject. In case the information provided in 
the e-diary is not sufficient to assess the bleeding episode, the subject must be called and/or visit 
the site. The discussions with the subject on the importance of a healthy liver and factors that 
might impact liver health (including acetaminophen and alcohol intake), will continue. In 
addition, use of concomitant medication and occurrence of AEs will be continuously monitored. 
Subjects are permitted to continue their continuous routine factor IX treatment in the first weeks 
after dosing. At Visit F1 (Week 1), 1 week after IMP administration, the subjects will visit the 
clinic for endogenous factor IX activity assessment (by local and central laboratory). During the 
post-treatment follow-up visits, factor IX activity levels will be monitored throughout the study. 
If the endogenous factor IX activity result is ≥ 5%, continuous routine factor IX prophylaxis will 
be discontinued, and further management will be based on Investigator’s clinical judgement and 
subject preference. Continuation or re-initiation of continuous routine factor IX prophylaxis may 
be considered if the endogenous factor IX activity is between 2 and 5% in at least 2 consecutive 
laboratory measurements, based on the Investigator’s clinical judgement and subject preference. 
If endogenous factor IX activity is < 2%, continuous routine prophylaxis must be continued or 
reinstated. Additional on-demand and/or intermittent prophylactic factor IX treatment may be 
given after treatment with CSL222, if considered necessary. 
Vital signs are measured at each visit in this phase. A physical examination is performed at 
Visits F1, F2, F4, F6, F12, F13, F15, F17, F19, and F-Final (Weeks 1, 2, 4, 6, and 12, and 
Month 4, 6, 8, 10, and 12 [Week 52]). Samples for efficacy and safety laboratory parameters and 
hematology and serum chemistry, are taken at each visit except for the samples for factor IX 
antibodies and factor IX inhibitors (taken at Visits F6, F12, F15, and F-Final [Weeks 6 and 12, 
and Months 6 and 12]), semen sampling for shedding (taken at Visits F6, F12, F13, F15, and 
F-Final [Weeks 6 and 12, and Months 4, 6, and 12]), total (IgM and IgG) antibodies and NABs 
to AAV5 (taken at Visits F3, F6, F9, F12, F15, and F-Final [Weeks 3, 6, 9, and 12, and Months 6 
and 12]), and the blood sample taken for future research (taken at Visits F12 [Week 12] and 
F-Final [Week 52/Month 12]; Table 2). At Visit F15 (Month 6) and Visit F-Final 
(Month 12/Week 52), it is recommended that each subject should complete the PRO 
questionnaires, including PROBE (if applicable), prior to the interview by the trial physician and 
any other trial related procedures. 
For subjects participating in the MSKUS sub-study, assessments will occur at Visit F15 
(Month 6) and Visit F-Final (Month 12/Week 52). 

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Additionally, at Visit F-Final (Month 12/Week 52), an abdominal ultrasound is performed, the 
joint status (HJHS) is evaluated, the e-diary data devices are collected, the study-specific paper 
diaries for the long-term follow-up are provided, and the complete efficacy and safety data are 
analyzed and reported. 
6.1.4.1 Early Discontinuation 
The procedures listed for the final visit (Visit F-Final [Month 12/Week 52]), with the exception 
of the distribution of the study-specific paper diaries for the long-term follow-up, must also be 
performed at early discontinuation (refer also to Section 4.5), but prior to Week 52. In case a 
subject discontinues after Week 52 but prior to Month 60, he must complete the LTF8 
(Month 60) assessments/procedures. 
6.1.5 Long-term Follow-up (Visit LTF1 to LTF8 [Months 18 to 60]) 
During the long-term follow-up, subjects will visit the clinic every 26 weeks (6 months 
± 2 weeks). At each visit, the following assessments will be done: review of AEs and 
concomitant medications, collection of bleeding and factor IX use data, abdominal ultrasound, 
and sampling for efficacy and safety laboratory parameters. It is recommended that the subject 
completes the PRO questionnaires, including PROBE (if applicable), at Visits LTF2 (Month 24), 
LTF4 (Month 36), LTF6 (Month 48), and LTF8 (Month 60), prior to any other trial procedure is 
performed at the visit. Evaluation of HJHS (joint status) and evaluation of the MSKUS (if 
applicable) will also be performed at Visit LTF2 (Month 24), LTF4 (Month 36), LTF6 
(Month 48), and LTF8 (Month 60). A physical examination will be performed at Visits LTF1 
(Month 18), LTF2 (Month 24), LTF3 (Month 30), LTF4 (Month 36), LTF6 (Month 48), and 
LTF8 (Month 60). There should be an additional contact moment between site staff and subject 
in between these routine visits to facilitate at least quarterly (± 2 weeks) monitoring of 
occurrence of AEs, proper completion of the study-specific paper diaries, and proper reporting of 
factor IX usage and bleeding episodes. Options for how visits may occur to accommodate safety 
concerns and restrictions due to COVID-19 are described in Section 3.1.1. 
Optional informed consent will be taken for tissue sampling intended for molecular integration 
analysis. Tissue samples will be collected from subjects who provide consent if the subject is 
diagnosed with a new tumor or suspected malignancy involving the liver or other tissue for 
which there is evidence of biological plausibility of vector integration, or if liver tissue becomes 
available for any other reason through a standard of care procedure (eg, liver transplant or 
resection) or through a planned autopsy upon the subject’s death. 
In the long-term follow-up, subjects will document their use of factor IX replacement therapy 
and bleeding episodes in study-specific paper diaries. Subjects are expected to bring their 
long-term follow-up bleed diaries and long-term follow-up factor IX use diaries to every study 
visit during the long-term follow-up phase. At each visit, site staff will collect the information 
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contact the site staff immediately in case of a bleeding episode and/or factor IX use in addition to 
completing the questions/information requested on the paper diaries to capture all information. 
Subjects who are on continuous routine factor IX prophylaxis during the long-term follow-up 
phase of the trial are required to contact the site staff immediately in case of a bleeding episode 
and/or factor IX use different from their routine factor IX prophylaxis, in addition to completing 
the questions/information requested on the paper diaries to capture all information. 
In total, each subject will be followed for approximately 5 years after administration of CSL222. 
This is in line with the European Medicines Agency (EMA) guideline on follow-up of subjects 
administered with a gene therapy medicinal product (EMA/CHMP/GTWP/60436/2007). 
At the end of the long-term follow-up, all end of trial procedures, ie, the LTF8 (Month 60) 
procedures, as detailed in Table 3 and Table 4, should be performed. Subjects will also be 
informed about the option to participate in a separate long-term follow-up extension trial 
(CSL222_3003) to monitor the long-term safety and efficacy of CSL222 from approximately 
5 to 15 years after treatment (Section 6.1.8).  
In case of a bleeding episode occurring within 2 weeks before a scheduled LTF visit at which 
QoL questionnaires should be completed, the study visits should be re-scheduled. The Medpace 
and/or CSL Behring Medical Directors should be contacted to discuss how to proceed in case the 
visit would need to be pushed out beyond the protocol-allowed visit window. 
6.1.6 Additional Visits 
The subject may be called in for additional visits, at the discretion of the Investigator. The 
subject may also contact the clinical trial site for an additional visit. 
An additional visit may include additional assessments, as deemed necessary by the Investigator, 
such as (but not limited to) physical examination, AE assessment, bleeding assessment and/or 
repetition of instructions to the subject regarding subject e-diaries (Section 6.1.1), additional 
blood and/or semen sampling, repetition of blood sampling due to erroneous results 
(Section 6.2.5), or conduct of measurements that were missed at the previous visit. 
6.1.7 Additional Care of Subjects After the Trial 
Subjects will have the option to participate in a separate long-term follow-up extension trial 
(CSL222_3003) after the completion of CSL222_3001 (Section 6.1.8). 
6.1.8 Long-term Follow-up Extension Trial (Not Part of This Trial) 
At the end of this trial, subjects will be informed about the option to participate in a separate 
long-term follow-up extension trial (CSL222_3003) to monitor the long-term safety and efficacy 
of CSL222 from approximately 5 to 15 years after treatment. Subjects will be asked to provide 
informed consent for this study at the first visit for CSL222_3003. 

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6.2 Trial Evaluations 
6.2.1 Demographic and Other Baseline Characteristics 
6.2.1.1 Demographics 
Demographics collected at screening include birth year (ie, age at screening visit), race, ethnic 
group, and gender according to local regulations. 
6.2.1.2 Medical History and Concomitant Illnesses 
Medical history is any previous medical condition or surgical event, ie, a condition/event that 
started prior to the screening visit but is not ongoing at the screening visit. A concomitant illness 
is a medical condition that is ongoing at the screening visit. Medical history pertaining to 
metabolic disorders (diabetes, pre-diabetes, metabolic syndrome), liver disease and hepatitis 
(metabolic associated fatty liver disease, non-alcoholic fatty liver disease, non-alcoholic 
steatohepatitis; hepatitis B status, history, and vaccination status; hepatitis C status, history, and 
eradication details; alcohol use), cancer/tumors (including any family medical history of cancer 
and specifically hepatocellular carcinoma), will be collected. 
Collection of historical medical information regarding hemophilia B is described in 
Section 6.2.1.4. Information to determine if a subject has liver fibrosis and steatosis will be 
collected by means of a FibroScan (preferable during screening or at an alternative time point, 
however at Visit L-Final at the latest). Liver fibrosis scores and steatosis (CAP) scores will be 
collected during FibroScan assessment. A screening FibroScan assessment is not needed if either 
1.) a FibroScan assessment has been performed in the year prior to screening for which CAP 
scores are available in the source documentation, or 2.) a liver biopsy has been performed within 
the 2 years prior to the screening for which fibrosis grade is documented and available in the 
source documentation. 
At screening, information on relevant medical history will be obtained and recorded. The 
following conditions and events will be considered relevant (bleeding events excluded): 
- Any surgical event or any chronic or ongoing medical condition, regardless of if it 
requires/required therapy or not 
- Any medical condition or surgical event that has resulted in sequelae 
- Any isolated or one-off medical condition or surgical event that has occurred within 
1 year prior to screening irrespective of the outcome of the event. 
- Any isolated or one-off medical condition or surgical event that has resolved without 
sequelae and occurred more than 1 year prior to screening if judged relevant by the 
Investigator (for example conditions that the Investigator evaluates could re-emerge over 
time, eg, cancers). 

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6.2.1.3 Prior and Concomitant Medication/Therapy 
For the definition of prior medication/therapy, refer to Section 5.6.1. For the definition of 
concomitant medication/therapy, refer to Section 5.6.2. At every visit the Investigator or a 
qualified designee will ask the subject about concomitant medication. The Investigator should 
record the use of all medication (including over the counter medication, vitamin and/or mineral 
supplements, homeopathic remedies and herbal preparations) used and changes in the use of 
medication. Refer to Section 6.2.2.1 for instructions on recording of factor IX replacement 
therapy. The Investigator should also record other concomitant treatments/therapy, eg, 
physiotherapy. 
The following information will be recorded on concomitant medications: 
- Drug/therapy name (generic name preferred) 
- Indication 
- Dosing regimen (dose, unit, frequency, route) 
- Start date (if started ≥ 3 months prior to screening, then this can be stated instead of 
recording the specific start date) 
- Stop date (or ongoing, if ongoing at end trial participation). 
6.2.1.4 Hemophilia B Status and History 
At screening, the following medical history data related to hemophilia B will be recorded: 
- Date of initial diagnosis 
- Date symptoms were first observed 
- Date and value of endogenous factor IX activity assessment demonstrating factor IX 
activity of ≤ 2% or sufficient documentation within source documents of severity 
- Severity of Hemophilia B 
- Family members with a history of factor IX inhibitors 
- Arthropathy 
- Joint status as measured with HJHS version 2.1 (Section 6.2.2.5). 
- Number and location of target joints, defined as 3 or more spontaneous bleeds into a 
single joint within a consecutive 6-month period. Where there have been ≤ 2 bleeds into 
the joint within a consecutive 12-month period the joint is no longer considered a target 
joint  
- Registered name and dosage regimen of current continuous prophylactic factor IX 
replacement therapy (if applicable) 
- Hemophilia B related Surgical History 
o Date of surgery 
o Surgical event 

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6.2.1.5 History of Bleeding and Factor IX Use 
During screening the following historical information regarding bleeding and factor IX use will 
be collected and recorded in specific modules of the eCRF: 
Factor IX use data from 1 year prior to screening: 
- Factor IX product used (registered drug name) 
- Type of factor IX replacement therapy (on-demand or prophylaxis) 
- Start and stop date 
- Dose and frequency of dosing 
Bleeding data from 1 year prior to screening: 
- Number of spontaneous bleeding episodes 
- Number of traumatic bleeding episodes 
- Number of bleeding episodes for which it is unknown if they were spontaneous or 
traumatic 
- Number of joint bleeding episodes 
Information on invasive procedures requiring factor IX use in the year prior to screening: 
- Date of procedure 
- Type of procedure  
- Factor IX product used (Registered drug name)  
- Total factor IX dose (in International Unites [IU]) used for each procedure 
6.2.1.6 Factor IX Gene Sequencing (Optional) 
For those subjects who have given their consent, a blood sample for the purpose of factor IX 
gene sequencing analysis will be collected (preferably at screening, but otherwise at a later time 
point during the subject’s trial participation). Factor IX gene sequence analyses will be 
performed for all subjects that provide consent, even if they already have factor IX gene 
mutation information. 
Gene sequencing analysis will be performed at a central laboratory. 
6.2.2 Efficacy Evaluations 
For details on the timing and frequency of the assessments refer to Table 1 through Table 4. 
The name and address of each laboratory used in this trial will be maintained in the 
Investigator’s files at each site. 
Details for the laboratory processing instruction will be provided in the laboratory manual. 

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6.2.2.1 Factor IX Replacement Therapy 
From screening (Visit S) until Week 52 of the post-treatment follow-up (Visit F-Final), subjects 
will be asked to record all use of prophylactic and on-demand factor IX replacement therapy in 
an e-diary. If a subject is not able to enter the details into the e-diary, the site will be able to enter 
the information in the eCRF as long as the subject provides sufficient source documentation. The 
subject e-diary will include questions with respect to: 
- Reason for factor IX use (ie, continuous routine prophylaxis, selective prevention of a 
bleed [eg, because of upcoming physical activity, sports, etc], prophylaxis for 
invasive procedures, or other) 
- Date and time of factor IX infusion 
- Factor IX product used (Registered drug name) 
- Total factor IX dose in IU 
The Investigator/study nurse will review the e-diary entries for completeness and accuracy 
against the subject’s medical/hospital records. 
Information on actual factor IX replacement therapy used will be recorded by the subject in the 
e-diary. In addition, the prescribed factor IX replacement therapy regimen will be recorded in the 
eCRF. 
During the long-term follow-up phase, subjects will be expected to continue documenting 
factor IX replacement therapy in their paper long-term follow-up factor IX use diary, which they 
will bring with them to all study visits. 
Factor IX infusions are not recommended for subjects with factor IX activity in the 
non-hemophilic (≥ 40% of normal) range especially in subjects with a confirmed COVID-19 
infection, as increased thrombogenic risk is a known complication of COVID-19. Subjects with 
factor IX activity in the non-hemophilic range post-treatment with CSL222 and infected with 
COVID-19 may potentially be at the same risk of thrombosis as subjects without hemophilia; 
antithrombotic therapy for these subjects should be considered under the same guidelines 
recommended for those without hemophilia. 
6.2.2.2 Bleeding Episodes 
From screening (Visit S) until Week 52 of the post-treatment follow-up (Visit F-Final), subjects 
will record information of bleeding episodes in an e-diary. If a subject is not able to enter the 
details into the e-diary, the site will be able to enter the information in the eCRF as long as the 
subject provides sufficient source documentation. The subject e-diary will include questions 
regarding each bleeding episode with respect to:  
- Date and time of onset of bleed (start and stop) 
- Location of bleed 

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- Circumstances of bleed: spontaneous, traumatic, medical/dental/other procedure, 
unknown cause 
- Location and type of bleed 
- Symptoms associated with the bleed 
- Tests performed 
- Treatment of bleed with factor IX, and response to this treatment  
- Treatment other than factor IX (eg, pain medication, rest) 
During the long-term follow-up phase, subjects will be expected to continue documenting 
bleeding episodes in their paper long-term follow-up bleed diary, which they will bring with 
them to all study visits. 
In case of the occurrence of a bleeding episode as reported by the subject in the e-diary, the 
Investigator or designee needs to assess the bleeding episode as soon as possible but at least 
within 72 hours after it has been reported by the subject. In case the information entered in the 
e-diary is not sufficient to assess the bleeding episode, the subject needs to be called and/or visit 
the site. 
The Investigator will assess the bleed according to local standard of care (including potential 
imaging). The bleeding data and outcome should be recorded in source documents. 
Recurrent bleed: A bleed is defined as a recurrent bleed when, after no or minimal response to 
treatment, the bleed is occurring within 72 hours after stopping treatment for the original bleed 
for which treatment was initiated. 
Persistent bleed: A bleed is defined as a persistent bleed when the same bleed continues for more 
than 72 hours in the same location, without stopping treatment for the original bleed for which 
treatment was initiated. 
6.2.2.3 Factor IX Activity Levels and Factor IX Protein Concentration 
Blood samples for determination of endogenous factor IX activity and factor IX protein will be 
collected and assessed at the central and/or local laboratory as indicated in the schedule of events 
(Table 2 and Table 4). Central laboratory results for factor IX activity will be used in the 
analyses and local laboratory results for factor IX activity will be used for local monitoring of 
subjects. 
Throughout the study, it will be the aim to draw blood samples at those time points when the 
subject’s factor IX activity level is expected to be at its trough.  

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For subjects on continuous routine prophylactic factor IX replacement therapy: 
- 
The Investigator and/or study nurse will collaborate with the subject to schedule study 
visits to take place on days when continuous routine prophylactic factor IX replacement 
treatment is due to be administered. At these visits, blood sampling will take place prior 
to administration of prophylactic factor IX replacement therapy. 
- 
If a subject uses additional on-demand factor IX replacement treatment, his upcoming 
study visit may need to be re-scheduled (to the extent the visit window allows) so that the 
visit takes place at the time the subject resumes his continuous routine prophylaxis 
schedule.  
For subjects only using on-demand factor IX replacement therapy (only applicable after 
CSL222 administration):  
- 
If a subject uses on-demand factor IX replacement treatment, his upcoming study visit 
may need to be re-scheduled (to the extent the visit window allows) so that the visit does 
not take place within 5 half-lives of exogenous factor IX product use (Table 8). In case 
the 5 half-lives washout extends beyond the protocol-allowed visit window, the Medpace 
and/or CSL Behring Medical Directors should be contacted to discuss how to proceed. 
Contamination due to infused exogenous factor IX use begins at the date/time of infusion 
start and ends immediately after the date/time that is 5 times the half-life (of the factor IX 
medication) after the infusion start date/time. In case the infused factor IX medication is 
not listed in Table 8, the Medpace and/or CSL Behring Medical Directors should be 
contacted to discuss. 
Table 8 
Half-Life for Infused Exogenous Factor IX Medication by Commercial Name 
Medication Name 
Medical Half-Life (hour) 
ALPHANINE SD 
21 
ALPROLIX® 
88 
BeneFIX® 
22 
IDELVION® 
100 
Rebinyn®/Refixia® 
115 
RIXUBIS 
26 
 
Factor IX activity will be assessed by using the one-stage aPTT assay (local and central 
laboratory) and a chromogenic assay (central laboratory). 
6.2.2.4 Patient Reported Outcome: Quality of Life Questionnaires 
It is recommended that the PRO QoL questionnaires will be completed by the subject, after 
signed informed consent has been obtained and prior to any other visit procedure is initiated 
(when possible) at screening (Visit S), Visit L3, Visit L-Final, Visit F15 (Month 6), and every 
year post-baseline (Visits F-Final, LTF2, LTF4, LTF6, and LTF8 [Months 12, 24, 36, 48, 

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and 60]). The QoL questionnaires are to be completed under the supervision of a qualified and 
delegated study team member and are not to be given or sent to a subject to complete at home. 
For those subjects where Visit F15 (Month 6), Visit F-Final (Month 12), and/or a long-term 
follow-up visit are impacted by COVID-19, the QoL questionnaires may be conducted at the site 
within the following window: 
- 
Up to – 1 month prior to the target visit 
- 
Up to + 2 months after the target visit 
- 
And at least 4 months after the last QoL questionnaires assessment. 
Adjustments to this visit schedule will be documented.  
Questionnaires should be completed in the same order at each visit, following the presented 
order in the protocol: EQ-5D-5L, iPAQ, WPAI, BPI-sf, HAL, and Hem-A-QoL. 
In case of a bleeding episode occurring within 2 weeks before of a scheduled LTF visit at which 
QoL questionnaires should be completed, the study visits should be re-scheduled. The Medpace 
and/or CSL Behring Medical Directors should be contacted to discuss how to proceed in case the 
visit would need to be pushed out beyond the protocol-allowed visit window. 
EuroQol-5 Dimensions-5 Levels (EQ-5D-5L) 
The EQ-5D-5L questionnaire consists of the EQ-5D-5L descriptive system and the EQ VAS. 
The EQ-5D-5L descriptive system of health-related QoL states consists of 5 dimensions 
(mobility, self-care, usual activities, pain/discomfort, anxiety/depression) each of which can take 
1 of 5 responses. The responses record 5 levels of severity (No problems, slight problems, 
moderate problems, severe problems, and extreme problems) within a particular EQ-5D 
dimension. The EQ VAS is a standard vertical 20 cm VAS (similar to a thermometer) for 
recording an individual’s rating for their current health-related QoL state. 
International Physical Activity Questionnaire (iPAQ) 
The iPAQ assesses physical activity undertaken across a comprehensive set of domains including 
leisure time, domestic and gardening (yard) activities, work-related and transport-related activity. 
Two forms of the iPAQ have been developed: a short and a long version, both of which involve 
7-day recall of physical activity. For the current trial the short form will be used, which was 
designed to provide an evaluation of daily physical activities, and assesses the time spent sitting, 
walking, doing moderate-intensity and vigorous-intensity activity within the domains of work, 
transportation, domestic and gardening (yard) activities, and leisure-related activities. 

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Work Productivity and Activity Impairment Questionnaire (WPAI) 
The WPAI (Reilly et al, 1993) consists of 6 questions to assess the effect of health problems on a 
subject’s ability to work and perform regular activities. 
Brief Pain Inventory – short form (BPI-sf) 
The BPI-sf is a 9-item self-administered questionnaire used to evaluate the severity of a subject’s 
pain and the impact of this pain on the subject’s daily functioning. The subject is asked to rate 
their worst, least, average, and current pain intensity, list current treatments and their perceived 
effectiveness, and rate the degree that pain interferes with general activity, mood, walking 
ability, normal work, relations with other persons, sleep, and enjoyment of life on a 10-point 
scale. 
Hemophilia Activities List (HAL) 
The HAL measures the impact of hemophilia on self-perceived functional abilities. It contains 
42 multiple choice questions in 7 domains (lying/sitting/kneeling/standing, functions of the legs, 
functions of the arms, use of transportation, self-care, household tasks, and leisure activities and 
sports). 
Hemophilia Specific Quality of Life Index (Hem-A-QoL) 
The Hem-A-QoL is a specifically designed measure to capture aspects of QoL for adult subjects 
with hemophilia. It consists of 46 items pertaining to 10 dimensions (physical health, feelings, 
view of yourself, sport and leisure, work and school, dealing with hemophilia, treatment, future, 
family planning, partnership and sexuality) and a total score (WFH guideline for the 
management of haemophilia, 2012). 
6.2.2.5 Hemophilia Joint Health Score (HJHS) 
At screening (Visit S), Visit L-Final, and every year post-baseline (Visits F-Final, LTF2, LTF4, 
LTF6, and LTF8 [Months 12, 24, 36, 48, and 60]), the HJHS (version 2.1) will be assessed by a 
trained physician/physiotherapist/designee. In case of a bleeding episode occurring within 
2 weeks before a scheduled LTF visit at which the HJHS assessment should be completed, the 
study visit should be re-scheduled. The Medpace and/or CSL Behring Medical Directors should 
be contacted to discuss how to proceed in case the visit would need to be pushed out beyond the 
protocol-allowed visit window. 
The HJHS measures joint health, in the domain of body structure and function (ie, impairment), 
of the joints most commonly affected by bleeding in hemophilia: the knees, ankles, and elbows. 
The instruction manual for this assessment will be available in the ISF and must be followed. 
The summary score sheet must be completed and filed as source documentation for each 

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assessment. Preferably, the same assessor consistently performs the assessment on the individual 
subject throughout the entire trial period. 
6.2.2.6 Patient Reported Outcomes, Burdens, and Experiences (PROBE) Questionnaire 
(Optional) 
The following information applies only to subjects who have volunteered to participate in the 
optional PROBE Questionnaire Sub-Study. 
It is recommended that the PROBE questionnaire will be completed by the subject, after signed 
informed consent has been obtained and prior to any other visit procedure is initiated (when 
possible). The Short Form PROBE will be completed at screening (Visit S), Visit L-Final, and 
Visit LTF8 (Month 60). The PROBE Follow-up Form will be completed at Visit L3, Visit F15 
(Month 6), and every year post-baseline (Visits F-Final, LTF2, LTF4, and LTF6 [Months 12, 24, 
36, and 48]). The PROBE questionnaire should be completed after the other PRO questionnaires. 
The PROBE questionnaire is to be completed under the supervision of a qualified and delegated 
study team member and is not to be given or sent to a subject to complete at home. 
For those subjects where Visit F15 (Month 6), Visit F-Final (Month 12), and/or a long-term 
follow-up visit are impacted by COVID-19, the PROBE questionnaire may be conducted at the 
site within the following window: 
- 
Up to – 1 month prior to the target visit 
- 
Up to + 2 months after the target visit 
- 
And at least 4 months after the last PROBE questionnaires assessment. 
Adjustments to this visit schedule will be documented. 
The PROBE Questionnaire is a novel, patient-developed, PRO tool specific to hemophilia and 
intended to capture clinical outcomes that are considered relevant by patients. The Short Form is 
the full PROBE questionnaire minus the EQ-5D-5L. The Follow-up Short Form includes select 
questions from the Short Form (without the EQ-5D-5L). 
The objective of this sub-study is to provide data complementary to the compendium of 
established PRO tools regarding the impact of gene therapy on patient-relevant outcomes and 
quality of life over time. 
6.2.2.7 Musculoskeletal Ultrasound (MSKUS) (Optional) 
The following information applies only to subjects who have volunteered to participate in the 
optional MSKUS Sub-Study. 
MSKUS will occur, after signed informed consent has been obtained, at screening (Visit S), 
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(Month 12), and during the long-term follow-up at Visits LTF2 (Month 24), LTF4 (Month 36), 
LTF6 (Month 48), and LTF8 (Month 60). If it is not possible to obtain the MSKUS at screening 
(Visit S), it is allowed to obtain this first MSKUS at a later time point (preferably as soon as 
possible during one of the lead-in visits). Additional ultrasounds may be collected at the 
Investigator’s discretion. For those subjects where Visit F15 (Month 6), Visit F-Final 
(Month 12), and/or a long-term follow-up visit are impacted by COVID-19, scans may be 
conducted within the following window: 
- 
Up to – 1 month prior to the target visit 
- 
Up to + 2 months after the target visit 
- 
And at least 4 months after the last MSKUS. 
Adjustments to this visit schedule will be documented. 
Repeated bleeds into the joints can result in progressive damage to the joints, culminating in 
hemophilic arthropathy, mobility restrictions, and possible requirement for surgical repair. This 
sub-study will provide objective assessment of the effects of receiving gene therapy on the 
progression of physiological joint damage over time. 
Methodology for MSKUS plus scoring of MSKUS will be performed according to the J.A.D.E. 
protocol. The MSKUSs will be centrally analyzed and results assessed by subject over the course 
of the study. Full details can be found in the Musculoskeletal Ultrasound Manual. 
6.2.3 Safety Evaluations 
6.2.3.1 Adverse Events 
All AEs will be collected from signing of the informed consent form until the end of the 5-year 
follow-up. 
At each trial visit, subjects will be questioned in a general way to ascertain if AEs have occurred 
since the previous visit (eg, “Have you had any health problems since your last visit?”). During 
the long-term follow-up, AEs should be assessed at least quarterly by means of an additional 
contact between site staff and subject in between the scheduled visits. AEs are collected from the 
time informed consent is signed. 
For definitions of (S)AEs, and procedures regarding reporting of (S)AEs, refer to Section 7. 
6.2.3.2 Vital Signs 
Vital signs (blood pressure, pulse, and body temperature) will be measured at screening (Visit S), 
Visit L-Final, at pre-IMP and post-IMP (3 hours) on Visit D, and at all visits during the 
post-treatment phase. Before measurement of blood pressure and pulse, the subject should rest 

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for at least 5 minutes. For the individual subject, all measurements should be performed while 
the subject is in the same position (ie, sitting or lying) throughout the trial. 
Body temperature should be measured using the same method (eg, an ear thermometer) for the 
individual subject throughout the trial. 
Abnormalities (eg, high blood pressure) identified at the screening will be documented in the 
subject’s source documents and on the medical history eCRF. Changes after the screening Visit 
will be captured as AEs on the AE eCRF page, as deemed clinically significant in the opinion of 
the Investigator. These abnormalities are to be followed until they reached “final outcome” (refer 
to Section 7.9). 
6.2.3.3 Physical Examination (Including Height and Weight) 
A physical examination will be performed at screening (Visit S), L-Final, Visit D (pre-IMP), 
during the post-treatment follow-up at Visits F1, F2, F4, F6, F12, F13, F15, F17, F19, and 
F-Final (Weeks 1, 2, 4, 6, 12 and Months 4, 6, 8, 10, and 12), and during the long-term follow-up 
at Visits LTF1, LTF2, LTF3, LTF4, LTF6, and LTF8 (Months 18, 24, 30, 36, 48, and 60). 
Height will only be measured at screening and weight will only be measured at screening and 
Visit L-Final. 
Height (without shoes) will be measured and recorded, rounded to the nearest centimeter. Body 
weight (without overcoat and shoes) will be measured and recorded, rounded to the nearest 
kilogram. 
The physical examination will include general appearance and bedside examination of the 
following body systems: Lymph nodes, eyes and ears, mouth and throat, lungs, abdomen, 
extremities, musculoskeletal system, neurological system, cardiovascular system, and skin. 
The evaluation of each body system will be recorded as “normal” or “abnormal”. Abnormalities 
will need to be specified and recorded. 
Abnormalities (eg, scar at the left side at knee following total knee replacement, or arthropathy 
of left ankle due to hemophilia B) identified at screening will be documented in the subject’s 
source documents and on the medical history eCRF. Changes after the screening visit will be 
captured as AEs on the AE eCRF page, as deemed clinically significant in the opinion of the 
Investigator. These abnormalities are to be followed until they reached “final outcome” (refer to 
Section 7.9). 
6.2.3.4 Abdominal Ultrasound 
To monitor subjects for liver fibrosis and potential occurrences of liver malignancies, abdominal 
ultrasounds will be performed. These ultrasounds will occur at Visit L-Final at the latest (to 
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Table 1 and Table 3. For those subjects where Visit F-Final (Month 12), and/or a long-term 
follow-up visit are impacted by COVID-19, abdominal ultrasounds may be conducted within the 
following window: 
- 
Up to – 1 month prior to the target visit 
- 
Up to + 1 month after the target visit 
Adjustments to this visit schedule will be documented. 
Ultrasounds will be evaluated by qualified personnel at each site for fibrosis and malignancy. 
Abnormalities identified on the baseline abdominal ultrasound will be documented in the 
subject’s source documents and on the medical history eCRF. Changes after baseline will be 
captured as AEs on the AE eCRF page, as deemed clinically significant in the opinion of the 
Investigator. These abnormalities are to be followed until they reached “final outcome” (refer to 
Section 7.9). 
6.2.3.5 Anti-Factor IX Antibodies 
Anti-factor IX antibodies will be measured at the central laboratory, at baseline and at specific 
time points after IMP administration as specified in Table 2 and Table 4. 
6.2.3.6 Factor IX Inhibitors 
Factor IX inhibitors will be measured at the central laboratory with the Nijmegen modified 
Bethesda assay, and at the local laboratory with the Bethesda assay or Nijmegen modified 
Bethesda assay as specified in Table 2 and Table 4. Preferably, the same type of assay is applied 
consistently for the individual subject throughout the entire trial period. 
The Investigator (or designee) should enter analysis results from the local laboratory, as well as 
related reference ranges and analysis method applied (if applicable) in the eCRF. In addition, the 
local laboratory result reports should be kept in the subject’s medical record. 
A subject is said to suffer from factor IX inhibitors if he tested positive for factor IX inhibitors at 
2 consecutive tests, performed preferably within 2 weeks. 
If a subject is tested positive for factor IX inhibitors, a re-test should be performed preferably 
within 2 weeks to confirm the positive test. The subject should be called in for an additional visit 
in case no routine visit is scheduled within this 2-week timeframe. The subject should remain in 
the trial as per the clinical judgement of the Investigator. 
If a subject has confirmed factor IX inhibitors and continues with no change to treatment type for 
6 weeks and the factor IX inhibitor test is negative after that time, the factor IX inhibitor is 
classified as transient. 

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6.2.3.7 Factor IX Recovery 
Measurement of factor IX recovery (maximum concentration [Cmax]) and incremental recovery, 
measured as increase in activity per unit infused (IU/ml per U/kg) at 30 min after infusion (timed 
from end of infusion) of a dose of factor IX, will be performed at Visit L-Final. Additionally, 
measurement of factor IX recovery and incremental recovery should be done at suspicion of 
factor IX inhibitor (Section 6.2.3.6) or at increase in bleeding frequency, as judged by the 
Investigator. 
At each occasion, the subject’s continuous routine factor IX product/dose should be administered 
while at the clinical trial site. A blood sample should be drawn prior to administering the factor 
IX dose and at 30 minutes after the factor IX dose was administered. The blood sample should 
preferably be drawn from a vein different from the vein used for factor IX infusion. 
The continuous routine factor IX product/dose used for the baseline recovery assay should also 
be used when the assessment is repeated. 
Date of sampling, times of blood sampling (pre- and post-factor IX administration), time of 
subject’s continuous routine factor IX product/dose and identity of subject’s continuous routine 
factor IX product/dose will be recorded. 
Factor IX activity for the factor IX Recovery Assessment will be measured at a central 
laboratory using the one-stage aPTT assay. 
6.2.3.8 Total (IgG and IgM) and Neutralizing Antibodies to AAV5 
Sampling for total (IgG and IgM) and NABs to AAV5 will be performed at screening (Visit S), 
Visits L2 through LX, Visit L-Final, Visit D pre-IMP, during the post-treatment follow-up at 
Visits F3, F6, F9, F12, F15, and F-Final (Weeks 3, 6, 9, 12, and Months 6 and 12), and every 
year post-baseline (Visits LTF2, LTF4, LTF6, and LTF8 [Months 24, 36, 48, and 60]) as 
specified in Table 2 and Table 4. Total IgG and IgM antibodies will be assessed using an 
enzyme-linked immunosorbent assay (ELISA) and a luciferase-based bio-assay will be used for 
NABs to AAV5. The measurements will be performed at the central laboratory. Further details 
of the assays will be provided in the laboratory manual. 
6.2.3.9 AAV5 capsid-specific T cells 
Sampling for AAV5 capsid-specific T cells will be performed at baseline (Visit D, pre-IMP) and 
all visits during the post-treatment phase. 
AAV5 capsid-specific T cells will be measured at the central laboratory. 

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6.2.3.10 Vector Genome Detection 
Sampling of blood and semen to determine vector DNA levels will be performed at baseline and 
at specific time points post-baseline, as specified in Table 2 and Table 4, by means of 
quantitative (real-time) polymerase chain reaction (qPCR). Sampling should continue for the 
individual subject and for a specific matrix until 3 consecutive negative samples have been 
detected for the subject for that particular type of matrix. The sampling schedule may be 
increased (in frequency) as agreed between the Investigator and subject following the 
notification of a first negative result on blood and/or semen, expediting the opportunity to reach 
3 consecutive negative samples on the specific matrix. 
Based on the wish of the subject semen samples can be collected at home prior to attending the 
visit (on the visit day or on the day before the visit day). The sampling schedule may be reduced 
as agreed between the Investigator and subject. As per the inclusion criteria (Section 4.1), the 
subject must use a condom during sexual intercourse until 3 consecutive negative samples for 
AAV5 have been detected. In case a subject is not able to provide semen samples due to a 
medical condition, this should be recorded by the Investigator in the subjects’ medical record. 
6.2.3.11 Inflammatory Markers 
Blood samples will be taken at baseline (Visit D) and at specific time points post-baseline, as 
specified in Table 2 and Table 4 to assess IL-1β, IL-2, IL-6, IFNγ, and MCP-1 using ELISA. All 
assessments will be performed at the central laboratory. 
6.2.3.12 Other Safety Laboratory Evaluations 
All clinical laboratory assays will be performed according to the laboratory’s normal procedures. 
Reference ranges are supplied by the laboratory and used to assess the clinical laboratory data for 
clinical significance and out-of-range pathological changes. The Investigator should assess 
out-of-range clinical laboratory values for clinical significance, indicating if the value(s) is/are 
not clinically significant or clinically significant. Abnormal clinical laboratory values, which are 
unexpected or not explained by the subject’s clinical condition may be, at the discretion of the 
Investigator or Sponsor, repeated until confirmed, explained, or resolved as soon as possible. 
The safety laboratory assessments that will be performed at the central and/or local laboratory 
are specified in Table 9, and as indicated in the schedule of events (Table 2 and Table 4). 
 

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Table 9 
Safety Laboratory Parameters Assessed at the Central and/or Local Laboratory 
Central Laboratory 
 
Serum Chemistry 
Serum electrolytes (sodium, potassium), creatinine, creatine kinase, 
gamma-glutamyltransferase, AST, ALT, ALP, CRP, albumin, total bilirubin, glucose 
(non-fasting) 
Hematology 
Hemoglobin, hematocrit, platelet count, red blood cells, white blood cells with 
differential count, CD4+ count (all expressed in % as well as in absolute numbers) 
Coagulation 
aPTT, PT (or INR [International Normalized Ratio]) 
Serology 
HIV viral load, HBsAg, HBV DNA and HCV RNA 
Alpha-fetoprotein  
Alpha-fetoprotein (AFP)  
Local Laboratory 
AST and ALT 
ALP: alkaline phosphatase; ALT: alanine aminotransferase; aPTT: activated partial thromboplastin time; AST: aspartate 
aminotransferase; CRP: c-reactive protein; DNA: deoxyribonucleic acid; HBsAg: hepatitis B surface antigen; 
HBV: hepatitis B virus; HCB: hepatitis C virus; HIV: human immunodeficiency virus; PT: prothrombin time; 
RNA: ribonucleic acid. 
 
The Investigator should attempt to arrange with the local laboratory that analysis results are 
provided on the same day, or the day after, blood sampling has taken place. Local laboratory 
results should be provided as soon as possible to the Investigator. 
The Investigator (or designee) should enter analysis results from the local laboratory, as well as 
related reference ranges and analysis method applied (if applicable) in the eCRF. In addition, the 
local laboratory result reports should be kept in the subject’s medical record. 
Abnormalities identified at screening will be documented in the subject’s source documents and 
on the medical history eCRF. Changes after screening will be captured as AEs on the AE eCRF 
page, as deemed clinically significant in the opinion of the Investigator. These abnormalities are 
to be followed until they reached “final outcome” (refer to Section 7.9). 
6.2.4 Others 
6.2.4.1 Blood Sampling for Future Research (Optional) 
Four additional blood samples for the purpose of potential future research in the hemophilia B 
disease area (including development and validation of assays to support efficacy assessments) 
will be drawn (at screening [Visit S], baseline [Visit D pre-IMP], Visit F12 [Week 12], and 
Visit F-Final [Month 12/Week 52]). 
These additional blood samples will only be drawn if separate informed consent is given by the 
subject. Subjects who do not wish to donate blood samples for the purpose of potential future 
research may still participate in the trial and will not be required to withdraw from the trial if 
they withdraw consent for the potential future research. 
The procedures for the collection, processing, storage, and shipment of these blood samples are 
described in the Laboratory Manual. 

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6.2.4.2 Tumor, Suspected Malignancy, and Liver Tissue Sampling (Optional) 
If a subject is diagnosed with a new tumor or suspected malignancy involving the liver or other 
tissue for which there is evidence of biological plausibility of vector integration, tissue samples 
will be obtained during a standard of care procedure (eg, during a biopsy or definitive resection) 
and molecular analysis will be conducted, when possible, on the tissue sample(s) (see AEs 
qualifying for special notification in Section 7.2). This analysis is pursued to provide 
supplementary information to determine whether CSL222 has a causal role in the tumor 
development and will include, whenever possible, analysis of vector integration in the tumor 
tissue and whole genome sequencing. Tumors arising in sites or tissues for which biologic 
plausibility of vector integration is not established (eg, from the available literature, non-clinical 
data, or experience in clinical trials) will be evaluated on a case-by-case basis for consideration 
of molecular integration analysis. 
In addition to the reasons listed above, if liver tissue becomes available for any other reason 
through a standard of care procedure (eg, liver transplant or resection) or through a planned 
autopsy upon the subject’s death, liver tissue samples will be obtained for molecular analyses.  
Molecular analyses conducted with liver tissue samples will include investigation into how the 
gene therapy sequences are maintained within the cells of the liver over time; tolerance and/or 
stress within the cells of the liver; and/or how the gene therapy is expressed in different parts of 
the liver and across the liver architecture. This may include genetic research. Histologic evidence 
of inflammation, fibrosis, or other abnormalities will also be documented. Tissue from a tumor, 
suspected malignancy, or the liver will only be collected during the long-term follow-up phase of 
this study if the subject provides consent for this optional sample collection; this is entirely 
voluntary, and subjects may still participate in the trial if they do not wish to agree to donate a 
liver tissue sample. 
The clinical trial site should contact the Medpace and/or CSL Behring Medical Directors 
immediately upon awareness of a new tumor, malignancy or suspected malignancy, or if liver 
tissue becomes available for any reason (eg, biopsy, transplant, resection, subject death). 
6.2.5 General Information Regarding Laboratory Sampling and Results 
All laboratory assessments will be conducted at a central laboratory, except the factor IX activity 
assay for local monitoring of subjects (Section 6.2.2.3), factor IX inhibitor assay for local 
monitoring of subjects, and evaluation of subject eligibility (Section 6.2.3.6), and local 
monitoring of liver enzymes (AST and ALT; Section 6.2.3.12; also see the schedule of events 
[Table 2 and Table 4]). 
Dates and times of sampling will be recorded. 

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Detailed procedures for the collection, processing, storage, and shipment of central laboratory 
samples are described in the Laboratory Manual. This manual as well as all material such as test 
tubes and labels will be provided by the coordinating central laboratory. 
After the laboratory samples have been analyzed, they will remain stored for potential re-analysis 
at any time during the trial. Where allowed by local regulations, left over material of these 
samples may be used throughout the study to support studies in hemophilia B and/or gene 
therapy research, as well as related assay development to support such research. At a maximum 
of 15 years after the trial has been completed, all sample material will be destroyed. Exceptions 
are the future research blood samples, which will be stored and used for medical research until 
there is no sample remaining. 
The Investigator will be provided with those laboratory results needed for treatment 
decision-making (ie, laboratory results that inform safety monitoring or management of an 
individual subject at a site). The Investigator will receive serum chemistry, hematology, 
coagulation, serology, AFP, inflammatory markers, and gene sequencing results. Laboratory 
results will be provided at regular intervals for review and sign-off. Note that inflammatory 
markers will be analyzed by the central laboratory in batches and therefore reporting of these 
results to the Investigator is delayed. Any abnormality, judged by the Investigator as a clinically 
relevant worsening since the first measurement, should be reported as an AE, unless the 
laboratory abnormality is associated with an already reported AE. 
Any report of erroneous results from Visit F-Final (Month 12/Week 52) and onwards should 
prompt that the subject is called in for an Additional Visit to have blood sample(s) drawn for the 
purpose of re-measurement. 
The Additional Visit should preferably take place within 1 week after the report of the erroneous 
result(s). 
The Investigator will not be provided with results from the central laboratory for one-stage aPTT 
for factor IX activity, chromogenic assay for factor IX activity, factor IX protein concentration, 
anti-factor IX antibodies, factor IX inhibitors, factor IX recovery, total (IgM and IgG) antibodies 
to AAV5, neutralizing antibodies to AAV5, AAV5 capsid-specific T cells, or vector genome 
detection. Once there have been 3 consecutive negative results for vector genome detection (in 
blood and semen), the Investigator will be informed that these samples no longer need to be 
collected. 

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6.2.6 Volume of Blood to be Drawn From Each Subject 
Overall, a total of approximately 2370 mL blood will be drawn from each subject during this 
trial (excluding additional visits). A maximum of 120 mL will be taken per visit. A maximum 
amount of 110 mL will be drawn per additional visit. 
A minimum of approximately 2000 mL blood will be drawn between screening and the end of 
the post-treatment follow-up (Visit F-Final [Month 12/Week 52]). During the long-term 
follow-up, approximately 450 mL blood will be drawn. 
The amount of blood to be taken for each assessment may vary according to the instructions 
given in the laboratory manual. The overall total amount of blood that will be drawn from each 
subject may vary according to the number of additional visits needed for the individual subject. 
When multiple assessments need to be done at the same time point/visit, and they require the 
same type of tube, the assessments may be combined. 

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7 SAFETY DEFINITIONS, REPORTING AND FOLLOW-UP 
7.1 Adverse Event Definitions 
An AE, an adverse drug reaction (ADR), and a SAE are defined according to 
ICH Guideline E2A. 
An AE is any untoward medical occurrence in a subject administered the IMP and which does 
not necessarily have a causal relationship with this IMP or the IMP administration procedure. An 
AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory 
finding), symptom, or disease temporally associated with the use of the IMP including the IMP 
administration procedure. The definition also covers medication errors and uses outside what is 
foreseen in the protocol, including misuse and abuse of the product. 
An ADR is an untoward and unintended response to the IMP related to any dose administered. A 
causal relationship between the IMP and the AE is at least a reasonable possibility. 
An SAE is any untoward medical occurrence that at any dose: 
• 
Results in death 
• 
Is life-threatening (this refers to an event in which the subject was at risk of death at the 
time of the event; it does not refer to an event that hypothetically might have caused 
death if it was more severe) 
• 
Requires in-patient hospitalization or prolongation of existing hospitalization 
• 
Results in persistent or significant disability or incapacity 
• 
Is a congenital anomaly or birth defect 
• 
Is judged medically important by the Investigator (this refers to an event, not resulting in 
any of the outcomes listed above, but may jeopardize the subject or may require 
intervention to prevent one of the other outcomes listed) 
A Suspected Unexpected Serious Adverse Reaction (SUSAR) is a suspected adverse reaction for 
which there is a reasonable possibility that the product caused the AE; is unexpected in 
accordance with applicable product safety information; and at any dose results in death, is 
life-threatening, requires hospitalization or prolongation of existing hospitalization, results in 
persistent or significant disability or incapacity, or is a congenital anomaly or birth defect. 
In the following situations events are not defined as an AE: 
• 
Medical or surgical procedure (eg, endoscopy, appendectomy); the condition that leads to 
the procedure is an AE 
• 
Anticipated day-to-day fluctuations of pre-existing disease(s) or condition(s) present or 
detected at the start of the trial that do not worsen 

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• 
Condition(s) for which pre-planned procedure(s) have been recorded at screening, 
including hospitalization(s), unless the condition(s) for which the procedure and/or 
hospitalization was planned has worsened from the first trial related activity after the 
subject has signed the informed consent form 
• 
Concomitant illness identified during the screening procedures will be recorded as 
medical history. However, whenever symptoms for these condition(s) worsen and/or 
become serious, then these events must be reported as an AE or SAE, as applicable. 
7.2 Adverse Events Qualifying for Special Notification 
In addition, the following AEs, both serious and non-serious, qualify for special notification as 
they are seen as safety issues of particular concern for Advanced Therapy Medicinal Product 
(ATMP) (ENTR/F/2/SF/dn D(2009) 35810. Brussels, 03/12/2009) and gene therapy medicinal 
products (EMA/CHMP/GTWP/60436/2007): 
• 
AEs related to the IMP administration procedure  
• 
Suspected or confirmed cases of opportunistic or serious infections that in the 
Investigator’s opinion might be related to the IMP 
• 
Unexpected reactions (eg, hypersensitivity, immunological, toxic or other as consequence 
of a change in the construction or function of the viral vector [eg, generation of 
replication competent virus]) 
• 
AEs related to product failure (including lack of efficacy) 
• 
AEs related to mandatory concomitant medication (eg, immunosuppression) 
• 
AEs related to medical devices which form part of the product or are used for application 
of the product 
• 
Development of any new/recurrent cancer. 
These AEs should be reported and followed in the same manner as SAEs. Note that the AEs may 
be serious or non-serious by definition (Section 7.1). 
7.3 Adverse Event Assessment Definitions 
7.3.1 Severity 
The Investigator should assess the severity of all AEs according to the following definitions: 
• 
Mild: A type of AE that is usually transient and may require only minimal treatment or 
therapeutic intervention. The event does not generally interfere with usual activities of 
daily living. 
• 
Moderate: A type of AE that is usually alleviated with specific therapeutic intervention. 
The event interferes with usual activities of daily living, causing discomfort but poses no 
significant or permanent risk of harm to the research subject. 

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• 
Severe: A type of AE that interrupts usual activities of daily living, or significantly 
affects clinical status, or may require intensive therapeutic intervention. 
For reporting of S(AE) related laboratory abnormalities, the severity (intensity) needs to be 
evaluated in accordance with the defined criteria for assessment of laboratory value 
abnormalities. 
Note the distinction between seriousness and severity: The term severe is used to describe the 
intensity of the event and a severe event is not necessarily serious (eg, a severe headache would 
probably not constitute an SAE; however, a mild myocardial infarction could constitute an SAE). 
The seriousness criteria serve as a guide for defining regulatory reporting obligations. 
If an AE changes severity over time, the severity of maximum intensity should be reported. 
7.3.2 Relationship to IMP 
The Investigator must assess the causal relationship of the IMP for each (S)AE. The Investigator 
should decide whether, in his or her medical judgement, there is a reasonable possibility that the 
event may have been caused by the IMP according to the following guidelines and must 
document the causality assessment in the source document. 
Term 
Relationship 
Definition 
Related 
Yes 
The temporal relationship between the event and the administration of the 
IMP is compelling and follows a known or suspected response pattern to 
that product; the response disappears or decreases on cessation or 
reduction of the IMP dose and/or it reappears or worsens when the IMP is 
administered. 
Possibly Related 
Yes 
The temporal relationship between the event and the administration of the 
IMP is compelling and/or follows a known or suspected response pattern to 
that product, but the event could reasonably be explained by the subject’s 
medical condition, other therapies, or accident. 
Unlikely Related 
No 
The temporal relationship between the event and the administration of the 
IMP is less compelling and/or does not follow a known or suspected 
response pattern to that product; the event could plausibly be explained by 
the subject’s medical condition, other therapies, or accident.  
Not Related 
No 
The event can be readily explained by other factors such as the subject’s 
underlying medical condition, concomitant therapy, or accident and no 
plausible temporal or biologic relationship exists between the IMP and the 
event. In addition, this assessment can be used in cases where the subject 
did not receive any treatment with IMP. 
 

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7.4 Reporting of Adverse Events 
All events meeting the definition of an AE must be reported in the period starting at the first visit 
during which any trial related activity takes place (ie, as of ICF signature date) until the end of 
trial participation. Only medically qualified personnel (Investigators) must assess AEs. 
AEs must be reported in the source data and the eCRF. The diagnosis will be recorded, if 
available and applicable. If no diagnosis is available, each sign and symptom will be recorded as 
individual AEs. 
Recurring AEs should be reported separately, ie, with separate start date and time and stop date 
and time. 
7.5 Prompt Reporting of SAEs and Other Events to CSL Behring 
SAEs, AEs qualifying for special notification, and pregnancies must be reported as described in 
Table 10 (once the Investigator determines that the event meets the protocol definition for that 
event). 
Table 10 
Timing of Reporting and Follow-up for (Serious) Adverse Events, Adverse Events for Special 
Notification, and Pregnancies 
 
Initial Reports 
Follow-up Information on a Previous 
Report 
Type of Event 
Time Frame 
Documents 
Time Frame 
Documents 
All SAEs 
24 hours 
SAE form 
72 hours a 
SAE form 
All AEs qualifying for special 
notification as defined in 
Section 7.2 
24 hours 
SAE form 
72 hours a 
SAE form 
All pregnancies 
24 hours 
Pregnancy 
reporting form 
Once separate 
informed consent 
is given by the 
subject and 
pregnant partner, 
within 72 hours a 
Pregnancy 
reporting form 
a. 
If however, in the opinion of the Investigator, the follow-up information may have implications for the safety of 
other subjects, the follow-up information is to be reported immediately (ie, within 24 hours after initial report). 
 
The information will be reported on the respective form and will include assessment of 
seriousness, severity, causal relationship to the IMP or trial procedures, outcome, and a narrative 
description of the course of the event, as applicable. Additional information may be subsequently 
provided. 

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The reporting form and all other relevant documents supporting the reported SAE, AE qualifying 
for special notification, and pregnancy must be reported to CSL Behring. 
The IECs/IRBs and regulatory authorities will be notified of (S)AEs according to current 
regulation and local requirements. 
SAEs occurring to a subject after the subject has completed the clinical trial and for which a 
reasonable possibility of a causal relationship is assessed by the Investigator, should be reported 
by the Investigator to the Sponsor if the Investigator becomes aware of them regardless of the 
time that has elapsed (post-trial events). 
7.6 Regulatory Reporting Requirements for SAEs and Other Events 
Prompt notification by the Investigator to CSL Behring of SAEs and AEs qualifying for special 
notification, and pregnancy is essential, so that legal obligations and ethical responsibilities 
towards the safety of subjects are met. 
CSL Behring has a legal responsibility to notify both the local regulatory authority and other 
regulatory agencies about the safety of a product under clinical investigation. CSL Behring will 
comply with ICH/FDA/EMA and country-specific regulatory requirements relating to safety 
reporting to the regulatory authority, IECs/IRBs and Investigators. 
An Investigator who receives a SUSAR describing (an) SAE(s) or other specific safety 
information (eg, summary or listing of SAEs) from CSL Behring will acknowledge and file it in 
the appropriate section of the ISF and will notify the IECs/IRBs, if appropriate, according to 
local requirements (this information will also be filed in the appropriate ISF section by the 
Investigator). 
In addition to submission of SAEs, an annual development safety update report will be prepared 
and submitted to the EMA, FDA, and locally if applicable, according to the development 
international birth date. 
7.7 Reporting of Pregnancies 
Should a pregnancy occur in a female partner of male subject, it will be recorded separately from 
AEs, but will be reported in a manner identical to the reporting of SAEs, however via the use of 
a pregnancy reporting form instead of a SAE form. 
All attempts will be made to follow the pregnancy until the outcome of the pregnancy has been 
determined, and to capture information on the development of the infant in the period up until 
and including the age of 1 year. This information will only be collected if separate informed 
consent is given by the subject and the pregnant partner/infant’s mother. 

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Any report of a congenital abnormality/birth defect is an SAE and should be reported as such. 
Any complication of a pregnancy occurring during this trial, including elective termination for 
medical reasons, must be reported with the pregnancy reporting form. 
7.8 Reporting of Occupational Exposure 
Occupational exposure refers to the exposure to the IMP as a result of one’s professional or 
non-professional occupation. Any events of occupational exposure should be reported by the site 
according to local regulations and procedures. 
7.9 Follow-up on Adverse Events 
All S(AE)s should be followed until resolved or they have reached a “final outcome” or the 
subject’s participation in the trial ends, whichever comes first. 
Severe, non-serious AEs assessed as “Related” to IMP and all SAEs and AEs qualifying for 
special notification (regardless of their relationship to IMP) still ongoing after ended trial 
participation, should be followed on a regular basis according to the Investigator’s clinical 
judgement until a “final outcome” has been established. 
The outcome “recovering” can be used as the “final outcome” for events that are stabilized 
(ie, no further worsening is expected) and expected by the Investigator to resolve over time. 
The outcome “not recovered” can be used as the “final outcome” for events that are not expected 
to resolve over time (eg, cancer). 

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8 DATA MANAGEMENT 
8.1 Data Collection 
The Investigators’ authorized site personnel must enter the required information as per the 
protocol on the eCRF (note that authorized personnel from the data management vendor will 
enter the PRO questionnaire and HJHS summary data). A trial monitor will visit each site or 
perform virtual monitoring in accordance with the monitoring plan and review the eCRF data 
against the source data for completeness and accuracy. Discrepancies between source data and 
data entered by the site on the eCRF will be addressed by qualified site personnel or the data 
management vendor for PRO questionnaire and HJHS summary data. When a data discrepancy 
warrants correction, the correction will be made by authorized site personnel or by authorized 
personnel from the data management vendor, where applicable. Data collection procedures will 
be discussed with the site personnel at the site initiation visit and/or at the Investigator’s 
Meeting. It is expected that site personnel will complete the eCRF entry within 5 business days 
of the subject’s visit. 
The subject reported e-diary data will be directly loaded from the application into the eCRF up to 
Week 52, without source documentation. All other data will have separate source documentation; 
this data will not be recorded directly onto the eCRF. 
8.2 Clinical Data Management 
Data are to be entered into the eCRF as specified in data entry instruction. Quality control and 
data validation procedures are applied to ensure the validity and accuracy of the clinical 
database.  
Data are to be reviewed and checked for omissions, errors, and values requiring further 
clarification using computerized and manual procedures. Data queries requiring clarification are 
to be communicated to the site for resolution. Only authorized personnel will make corrections to 
the clinical database, and all corrections are documented in an auditable manner. 
To aid in CSR reporting of missed visits due to COVID-19, the eCRFs will capture if a visit is 
missed and reason(s) why. 
8.3 Study Data 
Study data identified in this protocol are collected, and source verified, on eCRF. All study data 
will be formulated into data sets to provide transparency, traceability, and integrity of trial 
analysis results from collection source to meet regulatory obligations for standardized study data. 
Observed study data will be mapped to the Clinical Data Interchange Standards Consortium 
(CDISC) Study Data Tabulation Model (SDTM) and serve as the source data from the trial. All 
study analyses will be completed using analysis data sets that are derived from the SDTM and 
follow the CDISC Analysis Data Model (ADaM) architecture. 

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8.3.1 Clinical Data – CDISC Study Data Tabulation Model (SDTM) 
Domains will be mapped to CDISC SDTM (current version at the time of mapping). No derived 
data required for analysis are included in the SDTM domains. All SDTM domains will be fully 
documented with define documents (DEFINE.XML) and a reviewer’s guide after database lock 
and final analyses are completed. 
8.3.2 Analysis Data – CDISC Analysis Data Model (ADaM) 
All planned and exploratory analyses will be completed using the ADaM data sets derived from 
the SDTM domains for this study. Analysis data sets will contain all derived study endpoints 
required for analysis. All analysis data sets will be fully documented with define documents 
(DEFINE.XML) and a reviewer’s guide after database lock and final analyses are completed. 

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9 STATISTICAL METHODS 
9.1 Statistical Analysis 
Details regarding the statistical methods and definitions for all study endpoints will be provided 
in the SAP, which will be finalized prior to database lock. The SAP will include a full 
description of the availability of data, timing of analyses and reporting, and will include 
templates for the tables, figures, and listings to be provided. 
Any agreed deviations from the SAP will be justified in the CSR.  
Statistical analyses will be performed using SAS Version 9.4 or higher (SAS Institute, Cary, 
NC 27513). 
9.2 Interim Analyses 
The first secondary endpoint, endogenous factor IX activity at 6 months after CSL222 dosing, 
will be assessed once the last subject has achieved 6 months after CSL222 treatment. This 
assessment will be based on clean data and a partially locked database. 
The second secondary endpoint, endogenous factor IX activity at 12 months after CSL222 
dosing, will be assessed once the last subject has achieved 12 months after CSL222 treatment. 
This assessment will be based on clean data and a partially locked database. 
9.3 Final Analysis 
Factor IX expression is anticipated to be stable within 6 months post-dose. After 52 weeks 
following stable factor IX expression, the primary assessment of ABR, as well as secondary and 
exploratory efficacy and safety data, will be analyzed as agreed per the SAP and will be reported 
in a CSR (18 months analysis). Data up to that point will be considered locked and will not be 
changed (with the exception of ending dates and outcomes for continuing events and treatments) 
without explicit authorization from the Sponsor. 
Following the 18 months post-dose assessments, subjects will be followed for another 3.5 years 
for evaluation of efficacy parameters and safety. At the end of that 3.5-year period, all safety and 
efficacy data will be reported in a CSR addendum covering the entire study duration, including 
the later 3.5-year period. 
The CSR and CSR addendum will summarize contingency measures implemented to manage 
study conduct due to COVID-19 control measures, protocol deviations due to COVID-19, and 
the impact COVID-19 had on visit schedules, missed visits, and missing information. 

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9.4 Selection of Subjects to be Included in the Analyses 
The FAS (Full Analysis Set) will include all subjects who are enrolled, entered the lead-in phase, 
are dosed with CSL222, and provide at least one efficacy endpoint assessment subsequent to 
CSL222 dosing. The FAS population will be the primary population for all efficacy statistical 
analyses. 
The PP population will include all subjects from the FAS population who adhere to a stable and 
adequate prophylaxis use during the lead-in phase, who complete at least 18 months of efficacy 
assessments (52 weeks after achieving stable factor IX expression) for the 18-month (data cut) 
analysis, who complete at least a full year of efficacy assessments for the 12-month (data cut) 
analysis, or who complete at least 6 months of efficacy assessments for the 6-month (data cut) 
analysis, and who have no major protocol deviations that impact the interpretation of efficacy. 
The PP population will be used for sensitivity analyses. Protocol deviations that impact the 
interpretation of efficacy include unwillingness to stop continuous routine factor IX prophylactic 
treatment after receipt of CSL222. Detailed rules for exclusion of data from the PP analysis will 
be established. 
The lead-in safety population will consist of all subjects enrolled into the lead-in period. The 
post-treatment safety population will consist of all subjects who receive CSL222, irrespective of 
any protocol deviations. Period-specific safety tabulations will use the period-specific safety 
population for the “N” and denominator (for percentages). The safety population will consist of 
all subjects who are in either the lead-in safety population or the post-treatment safety 
population. 
The screen failure population will include all subjects who were screened but never entered the 
lead-in period. 
The lead-in discontinuers population will include all subjects who entered the lead-in period but 
discontinued from the study prior to CSL222 dosing. 
9.5 Subject Disposition 
A disposition table for CSL222_3001 for all subjects will be provided. This tabulation will 
include the number of subjects who were not treated, who received the study treatment, who 
discontinued from the study, and who completed the study. The number and percentage of 
subjects included in the FAS, PP, and Safety populations will also be tabulated. The reason for 
exclusion from the FAS, PP, and Safety populations will be summarized. Reasons for premature 
discontinuation from study treatment (ie, being treated with only a partial dose of CSL222) will 
be summarized for the Safety population. 
The data on subject disposition, protocol deviations (including those related to COVID-19), and 
informed consent will be listed. 

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9.6 Demographic and Baseline Characteristics 
Descriptive summaries of demographics and other baseline characteristics will be presented for 
the FAS, PP, and Safety populations. For quantitative variables, all summaries will include the 
number of non-missing observations, mean, median, SD, minimum, and maximum. For the 
qualitative variables, the summaries will include the number and percentage of subjects in each 
category or level. All data will be included in listings. 
Medical history will be coded using the most recent version of the Medical Dictionary for 
Regulatory Activities (MedDRA), summarized using the number of observations and 
percentages of subjects reporting each category, and listed for each subject. 
A full description of demographic variables will be included in the SAP. 
9.7 Investigational Product Exposure 
Listings for exposure to IMP will be provided showing the date of exposure and dose received.  
The time of subject’s routine factor IX product/dose, incremental recovery, maximum 
concentration, and identity of subject’s routine factor IX product/dose will be listed. 
9.8 Prior and Concomitant Medication 
Prior and concomitant medications will be collected and will be coded using the most recent 
World Health Organization drug dictionary. Prior and concomitant medications will be listed 
separately. 
9.9 Efficacy Analyses 
All efficacy analyses will be performed for the FAS and PP populations. Statistical analysis will 
be performed and plots and tabular displays will be created, visualizing individual effects for the 
selected efficacy measures as specified in the following sections. Analyses will be based on 
central laboratory measurements if results are available from both local and central laboratories. 
The primary efficacy analysis will be completed using the FAS population. The analysis using 
the PP population is considered to be a sensitivity analysis. 
9.9.1 Primary Efficacy Endpoints 
The primary efficacy endpoint is as follows:  
- 
ABR comparison between CSL222 and prophylaxis for non-inferiority between the 
lead-in phase and the 52 weeks following stable factor IX expression (months 6-18 
post-treatment) 

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Primary efficacy analysis for ABR 
ABR will be determined for the lead-in period and post-treatment period (for the 52 weeks 
following stable factor IX expression [months 6-18 post-treatment]). Analysis of the number of 
reported bleeding events will be performed using a repeated measures (RM) generalized 
estimating equations (GEE) negative binomial regression model accounting for the paired design 
of the trial with an offset parameter to account for the differential collection periods. An 
unstructured covariance matrix will be employed. If the model fails to converge, then a 
compound symmetry covariance structure will be used. The model will include the treatment 
(ie, period) as a categorical variable. If convergence is not attained, then initial parameter 
estimates will be provided. The estimated rate ratio, one-sided 97.5% Wald confidence interval, 
and the corresponding p-value will be determined. The upper limit of the resultant confidence 
interval of the rate ratio will be compared to the non-inferiority margin of 1.8. If the upper limit 
is less than 1.8, then non-inferiority will be declared. 
For the data cut at 52 weeks following stable factor IX expression (18 months post-treatment), 
ABR counts over the 52 weeks following stable factor IX expression (months 6-18 
post-treatment) will be used in the analysis. For data cuts prior to the post-treatment 18-month 
data cut, to allow time for CSL222 to become active and to allow the subject the opportunity to 
stop the lead-in prophylactic factor IX therapy, ABR counts beginning at Day 21 (of the 
post-treatment period) will be used in the analysis. 
The post-CSL222-administration time at risk of (having) a bleeding event is the subject’s time on 
the study between stable factor IX expression (Month 6; between Day 21 for pre-Month 18 data 
cuts) and the time that is 52 weeks following stable factor IX expression (18 months; that is 
1 year for the 12-month data cut), the time of study completion, or the time of early withdrawal 
from the study, whichever is earlier. Any bleeds prior to stable factor IX expression (Month 6; to 
Day 21 for pre-Month 18 data cuts) of the post-treatment period are not considered in the 
analysis. Events from the entire lead-in period will be counted, and the entire lead-in period is 
considered to be time at risk.  
In the analysis, any person-time during the post-treatment period within 5 half-lives subsequent 
to exogenous factor IX use will not be counted in the time at risk of (having) a bleeding event. 
Any bleeds occurring on or after stable factor IX expression (post-treatment Month 6; on or after 
Day 21 for pre-Month 18 data cuts) should still be counted as events, even if they occurred 
during a time interval of “contamination”.  
The main population for analysis will be the FAS. 

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9.9.2 Secondary Efficacy Endpoints and Order of Testing of Primary and Secondary 
Endpoints 
Secondary endpoints of the trial will focus on investigating the effect of 2 × 1013 gc/kg CSL222 
on endogenous factor IX activity, assessment of annualized consumption (and infusion rate) of 
factor IX replacement therapy, remaining free of previous continuous routine prophylaxis, 
assessment of trough factor IX activity, bleeding events, estimated ABR as a function of pre-IMP 
anti-AAV5 antibody titers using the luciferase-based NAB assay (as a “correlation” analysis), 
correlation of factor IX activity levels and observed anti-AAV5 antibody titers using the 
luciferase-based NAB assay after CSL222 dosing, occurrence and resolution of target joints, 
iPAQ, and EQ-5D-5L.  
Secondary efficacy endpoints are presented in Section 3.3.2. 
Efficacy analyses for factor IX activity 
For the factor IX activity analyses, the change in uncontaminated endogenous factor IX activity 
levels (by the one-stage aPTT assay) at 6 months, 12 months, and 18 months following a single 
treatment with CSL222 will be assessed once the last subject has achieved 6 months, 12 months, 
and 18 months after CSL222 treatment, respectively. The methodology, as described below for 
assessment after 18 months, will also be used for the 6-month and 12-month analyses.  
The change from baseline in factor IX activity (factor IXDIFF) will be tested:  
o Ho: factor IXDIFF = 0 (no effect of treatment) 
o H1: factor IXDIFF > 0 
The hypothesis that factor IXDIFF = 0 (ie, that the change from baseline is zero) will be tested and 
a one-sided p-value ≤ 0.025 will be regarded as statistically significant. 
The change from baseline in factor IX activity (percent of normal) at Month 18 will be analyzed 
using a RM linear mixed model. The baseline factor IX activity will be imputed as described in 
the SAP. If a subject has zero uncontaminated central-laboratory post-CSL222 factor IX activity 
values, the factor IX activity at Month 18 (and at any other post-AMT planned assessment time 
point that is to be used in the analysis) will be imputed based on the subject’s historical 
hemophilia B severity as documented on the CRF in a manner identical to that used for baseline 
factor IX activity. The model will include visit as a categorical covariate. A Toeplitz covariance 
matrix will be used to model correlation within a subject. If the Toeplitz model fails to converge, 
then a first-order autoregressive (AR(1)) structure will be used instead. In the AR(1) model, 
subject will be included as a random effect. If the AR(1) model also fails to converge, then 
subject will be modeled as a random effect in the absence of an AR(1) model. If convergence is 
still not attained, then initial parameter estimates will be provided. A contrast will be used to 
carry out the comparison at Month 18. The change from imputed baseline at Month 18, the 

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two-sided 95% confidence interval for the mean change, and the corresponding p-value for the 
comparison to zero will be obtained from the model and provided in a table. 
To allow time for CSL222 to become active and to allow the subject the opportunity to stop the 
lead-in prophylactic factor IX therapy, factor IX levels beginning with the Week 3 assessment 
will be used in the analysis. Visits post-CSL222 that are within 5 half-lives of exogenous factor 
IX use are considered contaminated and will also be excluded from this analysis. For the 
6-month analyses, a less refined contamination rule was used, whereby the date of exogenous 
factor IX infusion and the subsequent 9 days (10 discrete calendar days in total) were considered 
to be days of contamination with factor IX. The 12-month and 18-month analyses will use the 
more refined definition of contamination, based on 5 half-lives. 
The main efficacy analysis for factor IX activity will be completed using the FAS population. 
The analysis using the PP population is considered to be a sensitivity analysis. Sensitivity 
analyses will be conducted to account for missing data and will be specified in the SAP. 
Testing of Efficacy Endpoints 
Formal statistical testing of the efficacy endpoints will be performed using the closed testing 
principle (for Type I error control for multiple testing). Due to the closed testing principle, no 
correction for multiplicity is necessary. All endpoints will be tested for superiority at a one-sided 
alpha level of 0.025 (except as otherwise noted). Superiority and non-inferiority testing will be 
accomplished using the FAS population. Fixed sequential testing will be performed using a 
hierarchical approach and will be continued until a non-significant result is obtained (except as 
otherwise noted). 
The primary and secondary endpoints will be analyzed in the following order: 
1. ABR comparison between CSL222 and prophylaxis for non-inferiority between lead-in 
phase and the 52 weeks following stable factor IX expression (months 6-18 
post-treatment; primary efficacy endpoint) 
2. Endogenous factor IX activity at 6 months after CSL222 (first secondary efficacy 
endpoint) 
3. Endogenous factor IX activity at 12 months after CSL222 (second secondary efficacy 
endpoint) 
4. Endogenous factor IX activity at 18 months after CSL222 (third secondary efficacy 
endpoint) 
5. Annualized consumption of factor IX replacement therapy during the 52 weeks following 
stable factor IX expression (months 6-18 post-treatment), excluding replacement for 
invasive procedures, compared to the lead-in phase (secondary efficacy endpoint) 
6. Annualized infusion rate of factor IX replacement therapy during the 52 weeks following 
stable factor IX expression (months 6-18 post-treatment), excluding replacement for 
invasive procedures, compared to the lead-in phase (secondary efficacy endpoint) 

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7. Comparison of the percentage of subjects with trough factor IX activity < 12% of 
normal between the lead-in phase and after treatment with CSL222 over the 52 weeks 
following stable factor IX expression (months 6-18 post-treatment; secondary 
efficacy endpoint) 
8. ABR comparison between CSL222 and prophylaxis for superiority between the 
lead-in phase and the 52 weeks following stable factor IX expression (months 6-18 
post-treatment; secondary efficacy endpoint) 
9. Rate of spontaneous bleeding events during the 52 weeks following stable factor IX 
expression (months 6-18 post-treatment) compared to the lead-in phase (secondary 
efficacy endpoint) 
10. Rate of joint bleeding events during the 52 weeks following stable factor IX 
expression (months 6-18 post-treatment) compared to the lead-in phase (secondary 
efficacy endpoint) 
11. PRO questionnaire scores from the iPAQ (total physical activity score) during the 
12 months following CSL222 dosing compared with the lead-in phase (secondary 
efficacy endpoint) 
12. PRO questionnaire scores from the EQ-5D-5L VAS score during the 12 months 
following CSL222 dosing compared with the lead-in phase (secondary efficacy endpoint) 
 
Simultaneous one-sided 97.5% confidence intervals based on a graphical approach to multiple 
testing will be provided for the Type I error-controlled efficacy endpoints as a supportive 
analysis. For endpoints for which an increase is favorable, the lower one-sided 97.5% confidence 
bound will be provided; for endpoints for which an increase is unfavorable, the upper one-sided 
97.5% confidence bound will be provided. For any data cuts (ie, analysis times) that are not the 
main data cut for a given endpoint, the p-values and CIs will be considered to be descriptive 
rather than inferential. 
All data will be listed. 
A full description of the secondary analyses will be included in the SAP. 
9.9.3 Exploratory Efficacy Endpoints 
Exploratory endpoints are presented in Section 3.3.2. 
Exploratory analysis 
All exploratory endpoints will be presented using descriptive statistics, where applicable. No 
formal statistical testing will be required. Continuous endpoints will be summarized descriptively 
by visit (and by subset for the subset analyses). Analysis will be based on the FAS and the PP 
population. A full description of the exploratory analyses will be included in the SAP. 

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9.9.4 Optional Sub-study Endpoints 
Optional sub-study endpoints are presented in Section 3.3.3. 
The analysis for the optional PROBE Questionnaire sub-study will be described in the SAP. 
There will be a separate SAP document for the statistical analysis of the optional MSKUS 
sub-study results. 
Analysis will be based on the FAS population for the set of subjects participating in the 
respective sub-study. Any subject with at least one assessment of the sub-study endpoint will be 
considered to be participating in the respective sub-study. 
9.10 Safety Analyses 
Secondary safety endpoints to be analyzed are presented in Section 3.3.2.  
All TEAEs are tabulated by SOC and preferred terms within each SOC according to the 
MedDRA terminology list. TEAEs will also be tabulated by severity (mild/moderate/severe) and 
by relationship (related/not related) to trial medication, using frequency counts (number of 
subjects with event and number of events) and percentages. Similar tables will be created for 
TEAEs leading to premature discontinuation, deaths, and SAEs, if applicable. 
These summary tables will be presented by decreasing frequency of occurrence based on SOC 
and Preferred Term. 
An AE overview table will be created displaying the number of subjects (and percentage) 
experiencing an event and the number of events for: Any TEAE, mild/moderate/severe TEAE, 
definitely related/probably related/possibly related/unrelated TEAE, Serious TEAE, TEAE for 
special notification, and TEAE leading to discontinuation. 
The summary tables will be accompanied by individual subject listings of all AEs, including 
information on AE number, actual AE description, date/time of start and end of AE, preferred 
term (MedDRA), SOC (MedDRA), severity, relationship/causality, type of AE, seriousness, and 
outcome. Pre-existing AEs will be flagged. Pre-existing AEs are not considered to be 
treatment-emergent, except in case of worsening during/after trial treatment (to be collected as 
separate AE). Separate listings will be created for TEAEs for special notification, deaths, and 
SAEs, if applicable. 
Other safety data will be presented using graphical displays, as applicable, descriptive statistics 
(including change from baseline, if applicable), and/or individual data listing. 
The number of days until vector DNA can no longer be detected in semen and blood will be 
tabulated. The number of days is calculated using the date of collection of the first of 
3 consecutive negative sample for each matrix. 
All safety analyses will be based on the Safety population. 

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9.11 Sample Size Justification 
The study sample size is constrained by the non-inferiority analysis of the primary endpoint, 
ABR. 
Based on a literature search of trials in a similar clinical setting and the same underlying disease, 
as well as the previous CSL220 Phase I/II trial, a non-inferiority margin of 1.8 is assessed for the 
rate ratio of ABR between CSL222 (post-treatment) and factor IX prophylaxis (lead-in). For 
establishing the non-inferiority margin, an ABR of 2.4 between factor IX prophylaxis and 
placebo treatment has been assumed. Via simulation of ABR under a negative binomial 
distribution with a yearly rate of 2.4 events for lead-in and 1.9 for post-treatment, with a Pearson 
correlation of 0.05 for the number of events between the 2 periods, and with a common negative 
binomial dispersion parameter of 1.5, a sample size of N = 50 will demonstrate non-inferiority 
with a non-inferiority margin of 1.8 and a power of 82.0%. Therefore, the study should consist of 
at least 50 analyzable subjects. 
Given the sample size needed for ABR, this will produce a power > 95% for the secondary 
statistical analysis of endogenous factor IX activity. 
9.12 Data Monitoring Committee 
A DMC will be involved in the management of the overall CSL222 program including this 
clinical trial. The purpose of the DMC in this trial, CSL222_3001, is to monitor the safety of the 
subjects throughout the trial. 
The DMC will also be involved in monitoring the safety of the subjects in the dose confirmation 
trial, CSL222_2001, as well as to evaluate response to the treatment in terms of factor IX activity 
levels. The DMC has assessed whether observed factor IX activity levels in the subjects treated 
with CSL222 in the dose confirmation trial are within an expected range (as defined in the DMC 
charter) to determine if the administered dose in the dose confirmation trial is suitable for 
administration in this trial. If the DMC had determined that the observed response was not within 
the expected range, or they did not observe enough consistency of effect, to proceed to dosing in 
this trial, they could have elected to recommend up to 3 more subjects be treated at the same 
dose or recommend a second dose be studied in the dose confirmation trial. The DMC reviewed 
the 6-weeks post-treatment interim analysis results from the dose confirmation trial and 
confirmed that the dose of 2 × 1013 gc/kg for CSL222 met the intended safety and efficacy profile 
and that the same dose should be used in the treatment phase of this trial. 
In addition, the DMC will assess whether there is an impact of pre-existing NAB titers on 
clinical outcome following CSL222 (per criteria defined in the DMC charter). Should the DMC 
determine that there is a recognizable impact of a certain titer and above, they can recommend 
institution of an exclusion criterion based on these titers for further enrollment in the study. 

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DMC meetings will be held at set times during the trial as outlined in the DMC charter. Further 
details regarding the DMC can be found in the DMC charter, which will be available prior to the 
administration of IMP. 

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10 SPONSOR’S AND INVESTIGATOR’S RESPONSIBILITIES 
This trial is conducted in accordance with current applicable regulations, ICH GCP (E6[R2]), 
EU Directive 2001/20/EC, EU Regulation 536/2014 (after transition), EU Directive 2005/28/EC, 
FDA guidelines, ATMP guidelines and its updates, and local ethical and legal requirements. 
10.1 Sponsor’s Responsibilities 
10.1.1 Good Clinical Practice Compliance 
The trial Sponsor and any third party to whom aspects of the trial management or monitoring 
have been delegated will undertake their assigned roles for this trial in compliance with the ICH 
GCP Guideline E6(R2), and related detailed guidelines specific to ATMPs (ENTR/F/2/SF/dn 
D(2009) 35810), as well as with applicable regulatory requirements in the countries where the 
trial will take place. 
Representatives of the trial Sponsor, and/or the company organizing/managing the research on 
behalf of the Sponsor, conduct visits to sites to inspect trial data, subjects’ medical records, and 
eCRFs in accordance with current ICH GCP and the respective local and inter/national 
government regulations and guidelines. Records and data may additionally be reviewed by 
auditors or by regulatory authorities. 
The Sponsor ensures that Local Regulatory Authority requirements are met before the start of the 
trial. The Sponsor (or a nominated designee) is responsible for the preparation, submission, and 
confirmation of receipt of any Regulatory Authority and IRB/IEC approvals required prior to 
release of IMP for shipment to the site. 
10.1.2 Indemnity/Liability and Insurance 
The Sponsor ensures that a fully executed contract is in place prior to initiation of the trial, 
including appropriate wording on indemnification of the Investigator/the institution against 
claims arising from the trial, as per applicable regulations. 
The Sponsor ensures that suitable clinical trial insurance coverage is in place prior to the start of 
the trial. An insurance certificate is supplied to the Investigator as necessary. 
10.1.3 Public Posting of Trial Information 
The Sponsor will assure that key design elements of this protocol will be posted in a publicly 
accessible database such as Clinical Trials.gov, prior to the start of the trial. In addition, upon 
trial completion and finalization of the trial report the results of this trial will be either submitted 
for publication and/or posted in a publicly accessible database of clinical trial results. 
Information included in clinical trial registries may include participating Investigators’ names 
and contact information. 

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The Sponsor will retain ownership of all data. 
10.1.4 Submission of Summary of Clinical Trial Report to Competent Authorities of 
Member States Concerned and Independent Ethics Committees 
The Sponsor will provide a summary of the CSR within 1 year of the global end of the trial 
completion date to the competent authority of the Member State(s) concerned as required by 
regulatory requirement(s) and to comply with the Community guideline on ICH GCP. The 
Sponsor will provide the IRBs/IECs with a copy of the same summary.  
10.1.5 Trial Suspension, Termination, and Completion 
The Sponsor may suspend or terminate the trial or part of the trial at any time for any reason. If 
the trial is suspended or terminated, the Sponsor will ensure that the Investigator as well as 
applicable regulatory agencies and IRBs/IECs are notified as appropriate. Additionally, the 
discontinuation of a registered clinical trial will be published on the publicly available database 
(as applicable). 
The Sponsor will make an end of trial declaration to the relevant competent authority as required 
by Directive 2001/20/EC and Regulation 536/2014.  
Refer to Section 3.1 for the definition of the end of the trial. 
10.2 Investigator’s Responsibilities 
10.2.1 Good Clinical Practice Compliance 
The Investigator must agree to conduct the trial in accordance with ICH GCP Guideline E6, 
including related detailed guidelines specific to ATMPs and applicable regulatory requirements 
and guidelines.  
It is the Investigator’s responsibility to ensure that adequate time and appropriate trained 
resources are available at the site prior to commitment to participate in this trial. The Investigator 
should also be able to estimate or demonstrate a potential for recruiting the required number of 
suitable subjects within the agreed recruitment period. 
The Investigator will maintain a list of appropriately qualified persons to whom the Investigator 
has delegated significant trial-related tasks. Curriculum vitae for Investigators and 
sub-investigators are provided to the trial Sponsor (or designee) before starting the trial. 
If a potential research subject has a primary care physician, the Investigator should, with the 
subject’s consent, inform him or her of the subject’s participation in the trial. 
An international coordinating Investigator is appointed to review the final Clinical Trial Report. 
Agreement with the final Clinical Trial Report is documented by the signed and dated signature 

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of the coordinating Investigator, in compliance with Directive 2001/83/EC as amended by 
Directive 2003/63/EC and ICH Guidance E3 (1995). 
10.2.2 Protocol Adherence and Investigator Agreement 
The Investigator and any sub-investigators must adhere to the protocol as detailed in this 
document. The Investigator is responsible for enrolling only those subjects who have met 
protocol eligibility criteria. Investigators are required to sign an Investigator Agreement to 
confirm acceptance and willingness to comply with the trial protocol. 
If the Investigator suspends or terminates the trial at his or her site, the Investigator will promptly 
inform the Sponsor, the IEC/IRB, and, where applicable, the regulatory authority, and provide 
them with a detailed written explanation. If the trial is prematurely terminated or suspended for 
any reason, the Investigator will promptly inform the trial subject(s) and will assure appropriate 
medical care and follow-up for the subjects. The Investigator will also return all IMPs, 
containers, and other trial materials to the Sponsor. Upon trial completion, the Investigator will 
provide the Sponsor, IEC/IRB, and regulatory agency with final reports and summaries as 
required by (inter)national regulations. 
Communication with local IECs/IRBs, to ensure accurate and timely information is provided at 
all phases during the trial, may be done by the Sponsor, applicable Contract Research 
Organization (CRO), Investigator, or for multi-site trials, the coordinating Investigator according 
to national provisions and will be documented in the Investigator Agreement. 
10.2.3 Documentation and Retention of Records 
10.2.3.1 Electronic Case Report Forms 
Access to the eCRF system and data capture by the Sponsor/CRO should be supported, and 
should be handled in accordance with instructions from the Sponsor. 
The Investigator is responsible for maintaining adequate and accurate medical records from 
which accurate information is recorded onto eCRFs, which have been designed to record all 
observations and other data pertinent to the clinical investigation. Electronic CRFs must be 
completed by the Investigator or designee as stated in the site delegation log (note that 
authorized personnel from the data management vendor will enter PRO questionnaire and HJHS 
summary data on the appropriate eCRF pages). 
The subject reported e-diary data will be directly loaded from the application into the eCRF, 
without source documentation. All other data will have separate source documentation; this data 
will not be recorded directly onto the eCRF. 
All data sent to the Sponsor must be endorsed by the Investigator. 

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The clinical research associate (CRA)/Trial Monitor will verify the contents against the source 
data per the Monitoring Plan. If the data are unclear or contradictory, queries are sent for 
corrections or verification of data. 
10.2.3.2 Patient Reported Outcomes 
The PROs include the patient QoL questionnaires. It also includes the e-diary in which the 
subjects will record their use of factor IX replacement therapy and bleeding episodes. 
10.2.3.3 Recording, Access, and Retention of Source Data and Trial Documents 
Original source data to be reviewed during this trial will include, but are not limited to: subject’s 
medical file, original clinical laboratory requisition forms and reports, HJHS summary score 
sheets, PRO questionnaires and data available from the subjects e-diary device. 
All key data must be recorded in the subject’s medical records. 
The Investigator must permit authorized representatives of the Sponsor, the respective national, 
local, or foreign regulatory authorities, the IEC/IRB, and auditors to inspect facilities and to have 
direct access to original source records relevant to this trial, regardless of media. 
The CRA/Trial Monitor (and auditors, IEC/IRB or regulatory inspectors) may check the eCRF 
entries against the source documents. The consent form includes a statement by which the 
subject agrees to the monitor/auditor from the Sponsor or its representatives, national or local 
regulatory authorities, or the IEC/IRB having access to source data (eg, subject’s medical file, 
appointment books, original laboratory reports, X-rays etc). Non-trial site personnel will not 
disclose any personal information or personal medical information. 
These records must be made available within reasonable times for inspection, if required, by a 
properly authorized representative of any regulatory agency (eg, the US FDA, EMA, UK 
Medicines and Healthcare products Regulatory Agency [MHRA]) or other). 
Essential documents must be maintained according to local regulations or ICH GCP (E6[R2]) 
requirements, whichever is longer. Essential documents may not be destroyed without written 
permission from the Sponsor. Note that traceability records should be kept for a minimum of 
30 years after the expiry date of the product, or longer if required by the terms of the clinical trial 
authorization or by the agreement with the Sponsor.  
10.2.3.4 Audit/Inspection 
To ensure compliance with relevant regulations, data generated by this trial must be available for 
inspection upon request by representatives of, for example, the US FDA (as well as other US 
national and local regulatory authorities), the EMA, the MHRA, other regulatory authorities, the 
Sponsor or its representatives, and the IEC/IRB for each site. 

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10.2.3.5 Financial Disclosure 
The Investigator is required to disclose any financial arrangement prior to participating in the 
trial and for 1 year after, whereby the value of the compensation for conducting the trial could be 
influenced by the outcome of the trial. 
The Investigator should provide the following information: any significant payments from the 
Sponsor or subsidiaries such as a grant to fund ongoing research, compensation in the form of 
equipment, retainer for ongoing consultation or honoraria; any proprietary interest in IMP; any 
significant equity interest in the Sponsor or subsidiaries as defined in 21 Code of Federal 
Regulations (CFR) 54 2(b) (1998). 
In consideration of participation in the trial, the Sponsor pays the Investigator or nominated 
payee the sums set out in the payment schedule attached to the Investigator agreement. 
10.2.4 Compliance to all Regional, Local, State, and National Controlled-substance, 
Biohazard and Infectious Disease Regulations and Legislation 
When using controlled substances, biohazardous material, or substances for infectious diseases, 
the Investigator must at all times comply with all regional, local, state, and national laws 
pertaining to registration, reporting with the appropriate regulatory body and control and 
handling of such substances. 
10.3 Ethical Considerations 
10.3.1 Informed Consent 
It is the responsibility of the Investigator, or designee, to obtain voluntary written informed 
consent from all trial subjects prior to any trial related procedures including screening 
assessments. All consent documentation must be in accordance with applicable regulations, the 
GCP specific to ATMPs (ENTR/F/2/SF/dn D(2009) 35810) and ICH GCP (E6[R2]). In 
accordance with the ATMP guideline, the informed consent form and any other written 
information should include an explanation of particular issues associated with ATMPs, 
eg, inconveniences of long-term follow-up, specific risks such as shedding and the irreversible 
nature of the ATMP and other issues as further listed in the guideline. 
Each subject is requested to sign the Subject Informed Consent Form in their local language after 
the subject has received and read (or been read) the written subject information and received an 
explanation of what the trial involves, the particular issues arising with ATMPs, including but 
not limited to: the objectives, potential benefits and risk, inconveniences, and the subject’s rights 
and responsibilities. 

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If the ICF is revised with important new information that must be shared with the study subjects, 
the amended ICF will be presented, as required by the IRB/IEC for review and consideration by 
the subject, and signed re-consent is to be obtained.  
Separate written informed consents are to be obtained for the factor IX gene sequencing and 
future research samples prior to collection of the samples (as detailed in Section 6.2.1.6 and 
Section 6.2.4.1, respectively), the PROBE Questionnaire Sub-study (Section 6.2.2.6), and the 
MSKUS Sub-study (Section 6.2.2.7). 
A copy of all informed consent documentation (ie, a complete set of subject information sheets 
and fully executed signature pages) must be given to the subject. If applicable, it is provided in a 
certified translation of the local language. Signed consent forms must remain in each subject’s 
trial file and must be available for verification at any time. 
The principal Investigator provides the Sponsor with a copy of the local consent form which was 
reviewed by the IEC/IRB and which received their favorable opinion/approval. A copy of the 
IEC/IRB’s written favorable opinion/approval of these documents must be provided to the 
Sponsor, prior to the start of the trial unless it is agreed to and documented (abiding by 
regulatory guidelines and national provisions) prior to trial start that another party (ie, Sponsor or 
coordinating Investigator) is responsible for this action. Additionally, if the IEC/IRB requires 
modification of the sample Subject Information and Consent document provided by the Sponsor, 
the documentation supporting this requirement must be provided to the Sponsor. 
The Sponsor will also provide an optional informed consent to ask subjects to agree with 
providing a tissue sample if they are diagnosed with a new tumor or suspected malignancy 
involving the liver or other tissue for which there is evidence of biological plausibility of vector 
integration, or if a sample of their liver tissue becomes available for any other reason during the 
long-term follow-up phase of this study. Refer to Section 6.2.4.2 for further details.  
10.3.2 Institutional Review Board or Independent Ethics Committee 
For sites outside the EU, it is the responsibility of the Investigator to submit this protocol, the 
informed consent document (approved by the Sponsor or its designee), relevant supporting 
information and all types of subject recruitment information to the IECs/IRBs for review, and all 
must be approved prior to site initiation. 
For sites within the EU, the applicant for an IEC opinion can be the Sponsor, the Investigator, or 
for multi-site trials the coordinating Investigator or Sponsor, according to national provisions. 
Responsibility for coordinating with IECs/IRBs is defined in the Investigator Agreement. 
Prior to implementing changes in the trial, the Sponsor and the IECs/IRBs must approve any 
revisions of any revised informed consent documents and amendments to the protocol unless 
there is a subject safety issue (in that case approval can be after implementation). 

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IMP supplies will not be released until the Sponsor has received written IECs/IRBs approval of 
and copies of revised documents. 
For sites outside the EU, the Investigator is responsible for keeping the IECs/IRBs appraised of 
the progress of the trial and of any changes made to the protocol, but in any case, at least once a 
year. For sites within the EU, this can be done by the Sponsor, the Investigator or for multi-site 
trials the coordinating Investigator, according to national provisions. The Investigator must also 
keep the local IECs/IRBs informed of any serious and significant AEs. 
The names of the IECs/IRBs chairperson and the members of the IECs/IRBs will be collected as 
well as a statement that the IECs/IRBs works in accordance with the principles of ICH GCP. 
10.3.3 Subject Treatment Cards 
All subjects will receive a subject treatment card, which has been approved by the Sponsor and 
the IEC/IRB, containing at a minimum: 
- 
The name of the subject 
- 
The Investigator’s contact number 
- 
Information regarding the IMP received 
Treatment cards will be handed out at Visit D. If a subject is traveling to a different site for 
Visit D, this card should be handed out at the L-Final visit and the subject should be instructed to 
bring it with him to Visit D.  
10.4 Privacy and Confidentiality 
All US-based sites and laboratories or entities providing support for this trial, must, where 
applicable, comply with the Health Insurance Portability and Accountability Act of 1996 
(HIPAA). A site that is not a Covered Entity as defined by HIPAA, must provide documentation 
of this fact to the Sponsor. 
All EU-based sites and laboratories or entities providing support for this trial, must, where 
applicable, comply with the Data Protection Directive 95/46/EC (24 Oct 1995), EU data 
protection regulations No. 45/2001 (18 Dec 2001), and EU General Data Protection Regulation 
(GDPR) 2016/679 (27 Apr 2016). 
The confidentiality of records that may be able to identify subjects will be protected in 
accordance with applicable laws, regulations, and guidelines. The Sponsor has an internal policy 
that will be implemented in case of a data security breach. If a data security breach is identified, 
the identifier will alert the data privacy office via an internal service portal. A data privacy 
officer will be assigned to the case, and actions will be taken to support internal guidance, 
including notification to impacted parties. 

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After subjects have consented to take part in the trial, the Sponsor and/or its representative 
reviews their medical records and data collected during the trial. These records and data may, in 
addition, be reviewed by others including the following: independent auditors who validate the 
data on behalf of the Sponsor; third parties with whom the Sponsor may develop, register, or 
market CSL222; national or local regulatory authorities; and the IRBs/IECs, which gave 
approval for the trial to proceed. The Sponsor and/or its representatives accessing the records and 
data will take all reasonable precautions in accordance with applicable laws, regulations, and 
guidelines to maintain the confidentiality of subjects’ identities. 
Subjects are assigned a unique identifying number. However, birth year may be collected and 
used to assist the Sponsor to verify the accuracy of the data, for example, to confirm that 
laboratory results have been assigned to the correct subject. 
The results of trials – containing subjects’ unique identifying number, relevant medical data, and 
possibly birth year – will be recorded. They may be transferred to, and used in, other countries 
that may not afford the same level of protection that applies within the countries where this trial 
is conducted. The purpose of any such transfer would include: to support regulatory submissions, 
to conduct new data analyses to publish or present the trial results, or to answer questions asked 
by regulatory or health authorities. 
10.5 Publication Policy 
All manuscripts, abstracts, or other modes of presentation arising from the results of the trial 
must be reviewed and approved in writing by the Sponsor, in advance of submission. The review 
is aimed at protecting the Sponsor’s proprietary information either existing at the date of the 
commencement of the trial, or generated during the trial. Authorship will follow guidelines 
established by the International Committee of Medical Journal Editors (ICMJE, 2015). The 
publication policy with respect to the Investigator and clinical trial site will be further detailed in 
a separate document. 

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11 ADMINISTRATIVE ASPECTS 
11.1 Investigator(s) 
One principal Investigator and one or more sub-investigators will be appointed for each clinical 
trial site. Name and title of the Investigator(s) who is (are) responsible for conducting the trial, 
and the address and telephone number(s) of the trial site will be contained in other documents 
such as the Trial Procedures Manual and Clinical Trial Application forms.  
One National Coordinating Investigator will be appointed for each participating country. This 
Investigator will be responsible for national issues relating to the trial. 
Responsibilities of the Investigator are described in Section 10.2. 
11.2 International Coordinating Investigator 
The International Coordinating Investigator is responsible for approval of the clinical trial report 
on behalf of all trial Investigators. 
11.3 Clinical Trial Sites 
Clinical trial sites should have adequate resources and facilities to conduct the study. 
11.4 Vendors 
Trial management, vendor oversight, and medical monitoring oversight will be provided by CSL 
Behring. The Sponsor will engage vendors to perform the following services: 
- Laboratory analysis 
o Individual central laboratories will be applied for specific laboratory analyses. 
o One coordinating central laboratory will prepare the Laboratory Manual, sampling 
kits, perform training of clinical trial site personnel, arrange for courier shipments, 
and manage central preparation and storage of samples. 
- Storage, secondary packaging, shipping, and EU Qualified Person (QP) release of IMP 
- Clinical monitoring and project management 
- Regulatory 
- Medical Monitoring 
- Data Management 
- DMC Administration 
- Medical Writing 
- The provision of the PRO questionnaires 
- eTMF 
- Subject Travel organization and reimbursement 

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12 REFERENCE LIST 
Publications 
Bolton-Maggs P, Pasi K. Haemophilias A and B. Lancet. 2003;361:1801-09 
Boutin S, Monteilhet V, Veron P, Leborgne C, Benveniste O, Montus MF, et al. Prevalence of 
serum IgG and neutralizing factors against adeno-associated virus (AAV) types 1, 2, 5, 6, 8, and 
9 in the healthy population: implications for gene therapy using AAV vectors. Hum Gene Ther. 
2010;21:704-12 
Cantore A, Nair N, Della Valle P, Di Matteo M, Màtrai J, Sanvito F, et al. Hyperfunctional 
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Crudele JM, Finn JD, Siner JI, Martin NB, Niemeyer GP, Zhou S, et al. AAV liver expression of 
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factor IX expression by AAV-mediated gene transfer to skeletal muscle in an individual with 
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Kao CY, Yang SJ, Tao MH, Jeng YM, Yu IS, Lin SW. Incorporation of the factor IX Padua 
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Date: 12 Feb 2024 
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annualized bleeding and factor IX consumption for up to 2.5 years in adults with severe or 
moderate-severe hemophilia B treated with AMT-060 (AAV5-hFIX) gene therapy. The 
American Society for Hematology. 2018 
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therapy for hemophilia B. Sci China B. 1993 Nov;36(11):1342-51 
Manno C, Chew A, Hutchison S, Larson P, Herzog R, Arruda V, et al. AAV-mediated factor IX 
gene transfer to skeletal muscle in patients with severe haemophilia B. Blood. 2003;101:2963-72 
Manno C, Pierce G, Arruda V, Glader B, Ragni M, Rasko J, et al. Successful transduction of 
liver in haemophilia by AAV factor IX and limitations imposed by the host immune response. 
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Miesbach W, Meijer K, Coppens M, Kampmann P, Klamroth R, Schutgens R, et al. Gene 
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Nathwani A, Reiss U, Tuddenham E, Rosales C, Chowdary P, McIntosh J, et al. Long-term 
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Nathwani A, Reiss U, Tuddenham E, Chowdary P, McIntosh J, Riddell A, et al. 
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Protocol ID: CSL222_3001 
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Date: 12 Feb 2024 
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Guidelines 
Committee for Medicinal Products for Human Use (CHMP). Guideline on Follow-up of Patients 
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Step_4.pdf 
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Investigator’s Brochure AAV5-hFIX and AAV5-hFIXco-Padua (AMT-060 and AMT-061 
[etranacogene dezaparvovec]). Current Edition. 
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Guidelines for the management of hemophilia. 2nd ed., originally published in Haemophilia; 
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04985.htm date accessed: 06 December 2018 
World Federation of Haemophilia. Available from http://www.wfh.org/ 

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13 APPENDICES 
13.1 Laboratory Information 
Laboratory 
Test/Profile 
Medpace Reference Laboratories 
5365 Medpace Way 
Cincinnati, Ohio 45227, USA 
Central Laboratory: 
Coagulation 
Chemistry 
Inflammatory markers/cytokines 
Serology 
Hematology 
CD4 counts 
PBMC isolation for AAV5-capsid specific T-cell response (up 
until June 2019) 
Charles River 
Tranent, Edinburgh 
EH33 2NE, United Kingdom 
Referral testing: 
Vector genome detection (blood and semen) 
Unilabs 
Nygaardsvej 32 
DK-2100 Copenhagen 0 Denmark 
Referral Testing: 
Factor IX Activity: one-stage aPTT, chromogenic assay 
Factor IX protein concentration 
Factor IX inhibitors 
Anti-factor IX antibodies 
IgG antibodies AAV5/IgM antibodies AAV5 
Precision for Medicine 
8425 Progress Drive, Suite M 
Frederick, MD 21701 USA 
Referral Testing: 
PBMC isolation for AAV5-capsid specific T-cell response 
(starting July 2019) 
AAV5-capsid specific T-cell  
NABs to AAV5 
ARUP Laboratories 
500 Chipeta Way 
Salt Lake City, UT 84108 USA 
Referral Testing: 
Factor IX genetic sequencing 
Quest 
10101 Renner Blvd 
Lenexa, KS 66219 USA 
Confirmation Testing: 
HIV-1/2 Antibody differentiation test 
 

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13.2 Summary of Changes in Current Amendment 
Protocol Amendments 
Summary of Changes Since Last Version of Approved Protocol 
Amendment Number: 
8.0 (Version 9.0) 
Amendment Date: 
12 Feb 2024 
Global/Country/ Site-Specific:  
Global 
Description of Change 
Section(s) Affected by Change 
Addition of the protocol identification number assigned by 
CSL Behring for this trial and other CSL222 and CSL220 
trials. 
Global 
Addition of the drug code assigned by CSL Behring for 
AMT-061 and AMT-060. 
Global 
Update of trial management, vendor oversight, and medical 
monitoring oversight responsibilities from uniQure to CSL 
Behring. 
Global 
Clarification that subjects in Germany will be monitored at 
the clinical trial site for 8 hours after IMP administration for 
tolerance to the IMP and detection of potential immediate 
AEs. 
Clinical Trial Protocol 
Synopsis: Trial Design/ 
Methodology 
Table 1 
Table 2 
Section 1.5.1 
Section 5.3 
Section 6.1.3.3 
Clarification that subjects will be informed about the option 
to participate in a separate long-term follow-up extension 
trial (CSL222_3003) after the completion of CSL222_3001. 
Clinical Trial Protocol 
Synopsis: Trial Design/ 
Methodology 
Table 3 
Section 3.1 
Section 4.5 
Section 6.1.5 
Section 6.1.7 
Section 6.1.8 (new) 
Clarification that, in the event of a bleeding episode 
occurring within 2 weeks after a scheduled LTF visit at 
which the HJHS assessment should be completed, the visit 
should be re-scheduled. 
Table 3 
Section 6.2.2.5 

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Protocol Amendments 
Summary of Changes Since Last Version of Approved Protocol 
Amendment Number: 
8.0 (Version 9.0) 
Amendment Date: 
12 Feb 2024 
Global/Country/ Site-Specific:  
Global 
Expansion of optional tissue sampling to be performed. 
Table 4 
Section 6.1.1 
Section 6.1.5 
Section 6.2.4.2 
Section 10.3.1 
Clarification that safety follow-up information on factor IX 
usage and imaging assessments will be collected for 
subjects who withdraw from the trial. 
Section 4.5 
Revision of the maximum storage period for laboratory 
samples from 1 to 15 years. 
Section 6.2.5 
Clarification that results from the central laboratory that 
will not be provided to the Investigator. 
Section 6.2.5 
Clarification of the definition of a SUSAR. 
Section 7.1 
Clarification of procedures to be implemented in case of a 
data security breach. 
Section 10.4 
Minor corrections and clarifications, including word 
modifications and administrative changes. 
Global 
 

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13.3 Previous Amendments 
Protocol Amendments 
Summary of Changes 
Amendment Number: 
7.0 (Version 8.0) 
Amendment Date: 
07 Feb 2022 
Global/Country/Site-
Specific:  
Global 
Description of Change 
Section(s) Affected by 
Change 
The Sponsor was changed from uniQure to CSL Behring. 
All 
Minor administrative text and formatting updates. 
All 
It was clarified that uniQure will provide oversight to 
Medpace, the Monitoring CRO. 
Title Page 
Administrative changes to the identified Sponsor 
representative. 
Signature Page 
The entity responsible for safety oversight including 
SAE/AESI/pregnancy reporting was updated to CSL 
Behring, with details provided for contacting CSL Global 
Clinical Safety & Pharmacovigilance. 
Emergency Contact 
Information 
Section 7.5 
Section 7.6 
The identity and details for the uniQure Medical Director 
were updated. 
Emergency Contact 
Information 
It was clarified that for subjects only using on-demand 
Factor IX replacement therapy, study visits may need to be 
re-scheduled so that the visit does not take place within 
5 half-lives of exogenous factor IX product use. Table 8 
“Half-Life for Infused Exogenous Factor IX Medical by 
Name” was also added to clarify half-lives for infused 
exogenous factor IX medications. 
Table 1 
Table 2 
Table 3 
Table 4 
Section 6.2.2.3 
Table 8 
Footnote notation was adjusted for clarity in Table 4 
“Schedule of Events for Laboratory Parameters, for 
Long-term Follow-up (Visit LTF1 to LTF8)” for sampling 
for vector genome detection blood and semen. 
Table 4 
It was clarified that in case of a bleed occurring within 
2 weeks of a scheduled LTF visit at which QoL 
questionnaires should be completed, the study visits should 
be re-scheduled. 
Section 6.1.5 
Section 6.2.2.4 

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Protocol Amendments 
Summary of Changes 
Amendment Number: 
7.0 (Version 8.0) 
Amendment Date: 
07 Feb 2022 
Global/Country/Site-
Specific:  
Global 
Optional consent to ask subjects to agree with providing a 
tissue sample from their liver in case of death, or if the liver 
becomes available for any other reason (eg, liver 
transplantation or resection) during the long-term follow-up 
phase of this study was added. 
Section 6.2.4.2 
Section 10.3.1 
Due to the addition of Table 8, the previous Table 8 is now 
Table 9. Due to the addition of Table 8, the previous Table 9 
is now Table 10. 
Table 9 
Table 10 
The phrase “using the Common Terminology Criteria for 
Adverse Events severity grades” was removed from 
Section 9.10 
Section 9.10 
It was clarified that trial management, vendor oversight, and 
medical monitoring oversight will be provided by uniQure. 
Pharmacovigilance was removed from the list of services 
that the sponsor will engage vendors to perform. 
Section 11.4 
 
Protocol Amendments 
Summary of Changes 
Amendment Number: 
6.0 (Version 7.0) 
Amendment Date: 
28 Jun 2021 
Global/Country/Site-
Specific:  
Global 
Description of Change 
Section(s) Affected by 
Change 
Study objectives and endpoints were updated, based on input 
from the FDA.  
The primary objective and endpoint was updated to focus on 
ABR, 52 weeks following establishment of stable factor IX 
expression (months 6-18 post-treatment). 
The previously primary objectives and endpoints related to 
endogenous factor IX activity at 6 months and 12 months 
were moved to be the first and second secondary efficacy 
endpoints. Endogenous factor IX activity at 18 months after 
AMT-061 dosing was added as the third secondary efficacy 
endpoint. Estimated ABR as a function of pre-IMP 
Synopsis 
Section 2 
Section 3.3 
Section 9.9 
Section 9.10 

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Protocol Amendments 
Summary of Changes 
Amendment Number: 
6.0 (Version 7.0) 
Amendment Date: 
28 Jun 2021 
Global/Country/Site-
Specific:  
Global 
anti-AAV5 antibody titers using the luciferase-based NAB 
assay was added as a secondary efficacy endpoint (as a 
“correlation” analysis). EQ-5D-5L index scores during the 
lead-in phase (prophylaxis) and during the 12 months 
following AMT-061 dosing was added as an exploratory 
efficacy endpoint. The timing of other secondary and 
exploratory efficacy endpoints was clarified. 
To simplify, references to Section 3.3.2 and 3.3.3 were 
added in Section 9.9 and 9.10, to avoid repetition of the 
study endpoints. 
It was clarified that the FAS population would be used for all 
efficacy statistical analyses, with the PP population used for 
sensitivity analyses. The definition of the PP population was 
updated to clarify the timepoints used to identify the 
population for various data cuts. 
Synopsis 
Section 9.4 
To align with the updated endpoints, the statistical analyses 
were also reordered and timing clarified, including the order 
of endpoints for the fixed sequential testing of the primary 
and secondary efficacy endpoints. 
Synopsis 
Section 9.9.1 
Section 9.9.2 
As the primary objective was adjusted to focus on ABR, the 
description of the number of subjects, the sample size, and 
sample size justification, was similarly updated; the sample 
size remained at 50 subjects. 
Synopsis 
Section 3.4 
Section 9.11 
Details on the interim and final analyses were updated. The 
timing of the CSR was clarified to occur after 18 months 
post-treatment with AMT-061, instead of after 12 months. 
An interim analysis would still occur after 12 months to 
assess endogenous factor IX activity. The study period 
included in the CSR addendum was also clarified. 
Synopsis 
Section 3 
Section 9.2 
Section 9.3 
Clarification that during the long-term follow up, quarterly 
contact (± 2 weeks) should occur to monitor for AEs, proper 
completion of study-specific paper diaries, and proper 
reporting of factor IX usage and bleeding episodes 
Synopsis 
Table 3 
Section 3 
Section 6.1.5 

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Protocol Amendments 
Summary of Changes 
Amendment Number: 
6.0 (Version 7.0) 
Amendment Date: 
28 Jun 2021 
Global/Country/Site-
Specific:  
Global 
It was clarified that the calculation for the number of days 
until vector DNA can no longer be detected in blood and 
semen would be based on the first of 3 consecutive negative 
samples. 
Synopsis 
Additional detail on medical history to be specifically 
collected was added. 
Section 6.2.1.2 
 
Summary of Changes 
Amendment Number: 
5.0 (Version 6.0) 
Amendment Date: 
04 Feb 2021 
Global/Country/Site-
Specific:  
Global 
Description of Change 
Section(s) Affected by 
Change 
Update to uniQure Clinical Development and 
Pharmacovigilance signee. 
Clinical Trial Protocol 
Signature Page 
Update to uniQure Medical Director details. 
Emergency Contact 
Information 
The frequency of abdominal ultrasounds in the long-term 
follow-up phase was increased from yearly to every 
6 months. The abdominal ultrasound was added as a 
procedure that could be performed at an unscheduled visit 
during the long-term follow-up, if judged relevant by the 
Investigator. The permitted visit window for abdominal 
ultrasounds conducted at Visit F-Final and in the long-term 
follow-up phase when the visit is impacted by COVID-19 
was adjusted to be up to - 1 month prior to the target visit 
and up to + 1 month (previously up to + 2 months) after the 
target visit. 
Synopsis 
Table 1 
Table 3 
Section 6.1.5 
Section 6.2.3.4 
Clarification was added that subjects who are on continuous 
routine factor IX prophylaxis during the long-term follow-up 
phase of the trial are required to contact the site staff 
immediately in case of a bleed and/or factor IX use different 
from their routine factor IX prophylaxis, in addition to 
completing the questions/information requested on the paper 
diaries to capture all information. 
Synopsis 
Table 3 
Section 6.1.5 

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Summary of Changes 
Amendment Number: 
5.0 (Version 6.0) 
Amendment Date: 
04 Feb 2021 
Global/Country/Site-
Specific:  
Global 
For PRO questionnaires, the option to be considered a 
missed assessment if the questionnaires cannot be completed 
within the allowed visit window when a visit is impacted by 
COVID-19, was removed. It was clarified that adjustments 
to the visit timing within the allowed visit window are to be 
documented. 
Table 1 
Table 3 
Section 6.2.2.4 
For the PROBE questionnaire sub-study, the option to be 
considered a missed assessment if the PROBE questionnaire 
cannot be completed within the allowed visit window when a 
visit is impacted by COVID-19, was removed. It was 
clarified that adjustments to the visit timing within the 
allowed visit window are to be documented. 
Table 1 
Table 3 
Section 6.2.2.6 
For the MSKUS sub-study, the option to be considered a 
missed assessment if the scans cannot be completed within 
the allowed visit window when a visit is impacted by 
COVID-1, was removed. It was clarified that adjustments to 
the visit timing within the allowed visit window are to be 
documented. 
Table 1 
Table 3 
Section 6.2.2.7 
Local laboratory assessments of factor IX (one-stage aPTT 
for factor IX activity) and transaminases (AST/ALT) for 
local monitoring were added to the long-term follow-up. 
Reference to the schedule of events for laboratory 
parameters (Table 2 and Table 4) was added to the following 
sections, for clarity on the timing of these assessments 
during the study: 
Section 6.2.3.12 (Other Safety Laboratory Evaluations) 
Section 6.2.5 (General Information Regarding Laboratory 
Sampling and Results). 
Table 4 
Section 6.2.3.12 
Section 6.2.5 
To align with the eCRFs, the possible options for causality 
assessments for AEs were updated, with options being 
related, possibly related, unlikely related, and not related. 
Section 7.3.2 
 

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Summary of Changes 
Amendment Number: 
4.0 (Version 5.0) 
Amendment Date: 
15 Oct 2020 
Global/Country/Site-
Specific:  
Global 
Description of Change 
Section(s) Affected by 
Change 
The primary objective and endpoints were updated to include 
factor IX activity after 12 months (52 weeks) of AMT-061 
treatment and the non-inferiority assessment of AMT-061 
during the post-treatment follow-up compared to standard of 
care continuous routine factor IX prophylaxis treatment 
during the lead-in period, which were both previously 
secondary objectives/endpoints. Text references to the 
objectives throughout the protocol were updated as needed. 
The primary, secondary, and exploratory endpoints and 
associated analyses were rearranged/updated to align with 
the objectives update and for consistency and completeness. 
Exploratory endpoints for 2, 3, 4, and 5 years post-AMT-061 
treatment were added. 
Safety endpoints were updated for alignment and 
completeness. 
Synopsis 
Section 2 
Section 3.3 
Section 9.9 
Addition of comment that adjustments to the visit location 
and/or schedule may be made to accommodate safety 
concerns and restrictions due to the COVID-19 pandemic 
was added in discussion of the post-treatment follow-up 
phase, long-term follow-up phase, and PROBE and MSKUS 
sub-study. 
Synopsis 
Clarification that paper diaries are to be used during the long 
term follow for bleeds (long-term follow-up bleed diary) and 
factor IX use (long-term follow-up factor IX use diary) and 
brought to all clinic visits in this phase for reporting. 
Synopsis 
Table 3 
Section 6.1.5 
Section 6.2.2.1, 6.2.2.2 
Addition of a visit window for the PROBE questionnaire to 
be completed for Visit F15 (Month 6) and Visit F-Final 
(Month 12) and during the long-term follow-up period if 
those visits are impacted by COVID-19. 
Synopsis 
Section 6.2.2.6 
Addition of a visit window for MSKUS to be completed for 
Visit F15 (Month 6) and Visit F-Final (Month 12) and 
during the long-term follow-up period if those visits are 
impacted by COVID-19. 
Synopsis 
Section 6.2.2.7 

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Summary of Changes 
Amendment Number: 
4.0 (Version 5.0) 
Amendment Date: 
15 Oct 2020 
Global/Country/Site-
Specific:  
Global 
Description of Change 
Section(s) Affected by 
Change 
The label for the event of “Hematology parameters” was 
updated to “Hematology and coagulation parameters” to be 
more representative of the parameters being collected, as 
specified in the associated footnote. 
Table 2, Table 4 
Clarification that the sampling schedule for vector genome 
detection assessments can be increased as agreed between 
the Investigator and subject following the notification of a 
first negative result on blood and/or semen. 
Table 2, Table 4 
Section 6.2.3.10 
Section 1.6 “Accommodations Due to the COVID-19 
Pandemic” was added as an introduction to the COVID-19 
pandemic and its impact on clinical trial procedures. 
Section 1.6 (new) 
Section 3.1.1 “Considerations Due to the COVID-19 
Pandemic” was added to discuss potential adjustments to the 
meeting schedule or visit location/method due to the 
COVID-19 pandemic and to indicate that all deviations from 
the protocol due to the pandemic are to be documented. 
Section 3.1.1 (new) 
Recommendations on use of antithrombotic treatment was 
added for patients with factor IX activity in the 
non-hemophilic (≥ 40% of normal) range and with a 
confirmed COVID-19 infection. 
Section 5.6.2, 5.6.3 
Section 6.2.2.1 
Additional clarification and recommendations on 
transaminase elevation management was added including 
discussions on steroid tapering, considerations with 
prolonged high dose steroid use, and considerations with 
potential and confirmed COVID-19 infections. 
Section 5.6.4 
Addition of a visit window for QoL questionnaires to be 
completed for Visit F15 (Month 6) and Visit F-Final 
(Month 12) and during the long-term follow-up period if 
those visits are impacted by COVID-19. 
Section 6.2.2.4 
Addition of a visit window for abdominal ultrasounds to be 
completed for Visit F-Final (Month 12) and during the 
long-term follow-up period if those visits are impacted by 
COVID-19. 
Section 6.2.3.4 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 139 of 150 
Summary of Changes 
Amendment Number: 
4.0 (Version 5.0) 
Amendment Date: 
15 Oct 2020 
Global/Country/Site-
Specific:  
Global 
Description of Change 
Section(s) Affected by 
Change 
Removal of use of international criteria for assessment of 
laboratory value abnormalities. 
Section 7.3.1 
Clarification that trial monitor visits may be virtual. 
Section 8.1 
Mention of update to eCRFs to include COVID-19 reasons 
for missed visits. 
Section 8.2 
Specification that the protocol deviations includes those 
related to COVID-19. 
Section 9.5 
 
Summary of Changes 
Amendment Number: 
3.0 (Version 4.0) 
Amendment Date: 
30-Aug-2019 
Global/Country/Site-
Specific:  
Global 
Description of Change 
Section(s) Affected by 
Change 
Contact details for Medpace Clinical Safety were updated. 
Emergency Contact 
Information 
Under Trial Period (Planning), the timing of last subject last 
visit was updated to Q2 2025. 
Synopsis 
Details on sponsor-preapproved alternatives that may be 
used to collect liver fibrosis scores were added. 
Synopsis 
Table 1 
Section 6.1.1, 6.1.2 
An abdominal ultrasound to screen for liver malignancy was 
added at Visit L-Final at the latest (to establish baseline), 
Visit F-Final, and Visits LTF2, LTF4, LTF6, and LTF8. 
Section 6.2.3.4 Abdominal Ultrasound was added. 
Synopsis 
Table 1 and Table 3 
Section 6.1.2 and 6.1.4 
Section 6.2.3.4 
Vital signs (blood pressure, pulse, body temperature) was 
removed from the list of safety endpoints. 
Synopsis 
Section 3.3.2 
Exclusion criterion #3 was updated to allow subjects with 
total bilirubin > 2 times upper normal limit if this elevation 
is caused by Gilbert disease. 
Assessment of exclusion criterion #5 was updated to occur at 
screening (Visit S). Additionally, positivity for hepatitis B 
extracellular antigen (HBeAg) was removed as an additional 
criterion to Hepatitis B or C infection. 
Synopsis 
Section 4.2 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 140 of 150 
Summary of Changes 
Amendment Number: 
3.0 (Version 4.0) 
Amendment Date: 
30-Aug-2019 
Global/Country/Site-
Specific:  
Global 
Description of study endpoints and statistical analyses were 
updated to align with the current plans described in the SAP, 
including addition of sub-study endpoints and clarification of 
the study populations to be analyzed. 
Synopsis 
Section 3.3.2, 3.3.3 
Section 9.4, 9.5, 9.6, 9.7, 9.9 
It was clarified that blood sampling occurs prior to factor IX 
administration, and the requirement that this occurs at the 
clinic was removed. 
Table 1, Table 2, Table 3, 
Table 4 
Section 6.2.2.3 
The visit window for Visit S was updated to - 28 days 
Table 1 and Table 2 
The visit window for Visit L-Final was updated to - 28 days 
(± 7 days) from Visit D and it was specified that the time 
period between Visit LX and Visit L-Final can be less than 
2 months as long as the total lead-in period is a minimum of 
26 weeks. 
Table 1 and Table 2 
Section 3.1 
Section 6.1.2 
For recommended alcohol use, it was recommended that the 
daily alcohol limit in grams be adhered to most strictly 
during the first 12 weeks post-IMP and that the importance 
of abstaining from binge-drinking be reinforced at every 
visit. 
Table 1 
Section 6.1.1 
For subjects travelling to a different site for Visit D, it was 
clarified that they would receive their treatment card at the 
L-Final visit and instructed to bring it with them to Visit D. 
Subjects travelling for Visit D may provide their semen 
sample at Visit L-Final. 
Table 1 
Section 3.1 
Section 6.1.3.3 
Section 10.3 
The end of the clinical trial was defined as the point in time 
the last patient has completed the long-term follow-up 
observation period of 5 years after administration of the 
investigational medicinal product. 
Section 3.1 
Text was added explaining that Subjects who withdraw from 
the trial after enrolling in the Lead-in Phase but who are not 
dosed will be required to return their e-diary device and will 
not be requested to complete any final evaluations. 
Section 4.5 
It was clarified that each vial of AMT-061 will contain an 
extractable volume of at least 10 mL. 
Section 5.2 
It was clarified that subjects can receive their dose of 
continuous routine factor IX on the day of AMT-061 dosing. 
Section 5.6.2 
Section 6.1.3.3 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 141 of 150 
Summary of Changes 
Amendment Number: 
3.0 (Version 4.0) 
Amendment Date: 
30-Aug-2019 
Global/Country/Site-
Specific:  
Global 
Section 5.6.3 Guidelines for Use of Factor IX for Patients 
Undergoing Major Surgery was added. 
Section 5.6.3 
It was clarified that visits during the post-treatment 
follow-up period (from Week 1 up until Week 52) that do 
not include physical examination and/or PRO questionnaires 
may be performed at the subject’s home by an appropriately 
qualified and trained nurse, with agreement from the 
Investigator and Sponsor. 
Section 6.1.4 
The details on type of medical history data related to 
hemophilia B recorded were updated. 
Section 6.2.1.4 
It was clarified that for subjects who are not able to enter the 
details of their factor IX replacement therapy into the 
e-diary, the site can enter the information in the CRF as long 
as the subject provides sufficient source documentation. 
Section 6.2.2.1 
It was clarified that for subjects who are not able to enter the 
details of their bleeding episodes into the e-diary, the site can 
enter the information in the CRF as long as the subject 
provides sufficient source documentation. 
Section 6.2.2.2 
The description of iPAQ was updated, to include mention 
that this includes an assessment of the time sitting. 
Section 6.2.2.4 
It was specified that the methodology for MSKUS plus 
scoring of MSKUS will be performed according to the 
J.A.D.E. protocol. 
Section 6.2.2.7 
It was clarified that the Investigator will be provided with 
those laboratory results needed for treatment 
decision-making (ie, laboratory results that inform safety 
monitoring or management of an individual subject at a site). 
The Investigator will receive chemistry, hematology, 
serology, coagulation, and gene sequencing results at regular 
intervals for review and sign-off. Once there have been 
3 consecutive negative results for vector genome detection 
(in blood and semen), the Investigator will be informed that 
these samples no longer need to be collected. 
Section 6.2.5 
The approximately volume of blood to be drawn from each 
subject during the trial was lowered to 2370 mL. 
Section 6.2.6 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 142 of 150 
Summary of Changes 
Amendment Number: 
3.0 (Version 4.0) 
Amendment Date: 
30-Aug-2019 
Global/Country/Site-
Specific:  
Global 
Pharmacovigilance Department was updated to Medpace 
Clinical Safety. 
Section 7.5 
It was clarified that for clinical data, domains will be 
mapped to the current version of CDISC SDTM at the time 
of mapping. 
Section 8.3.1 
Storage, secondary packaging, shipping, and EU Qualified 
Person (QP) release of IMP was added to the list of services 
vendors are engaged for in this trial 
Section 11.4 
Laboratory details for testing of PBMC isolation for 
AAV5-capsid specific T-cell response, and of NABs, were 
updated. 
Section 13.1 
Appendix 13.2 Drug Induced Liver Injury Dataset was 
removed and reference to the source added in the protocol 
body. 
Section 5.6.2 
Section 13.2 (previous) 
 
Summary of Changes 
Amendment Number: 
2.0 (Version 3.0) 
Amendment Date: 
07 Dec 2018 
Global/Country/Site-
Specific:  
Global 
Description of Change 
Section(s) Affected by 
Change 
The title page was updated to show the name of the 
Monitoring CRO in place of the monitor’s name. 
Title Page 
Contact information for Medpace Clinical Safety was added.  
The Medpace Monitor was updated to the Medpace Medical 
Director and contact information for the uniQure Medical 
Director was added, with clarification and protocol- or 
safety-related issues must be sent to both of these 
individuals. 
Emergency Contact 
Information 
FIX was changed to factor IX throughout except in the name 
of the IMP. 
Global 
The planned number of sites was increased to approximately 
50. 
Synopsis 
Section 3.5 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 143 of 150 
Summary of Changes 
Amendment Number: 
2.0 (Version 3.0) 
Amendment Date: 
07 Dec 2018 
Global/Country/Site-
Specific:  
Global 
Description of Change 
Section(s) Affected by 
Change 
The dose of 2 × 1013 gc/kg AMT-061 will be the dose used 
in this study, as confirmed in the interim results from the 
CT-AMT-061-01 dose confirmation study. Text throughout 
the protocol was updated to reflect this. 
Synopsis 
Section 1.3.2.3 
Section 1.4 
Section 3.2 
Section 9.12 
Interim analysis results from the Phase IIb study 
CT-AMT-061-01 was added and sections updated to 
highlight CT-AMT-061-01 data and focus on AMT-061. 
Synopsis 
Section 1.3 
Section 1.4 
Section 1.5 
FibroScan™ was added as an assessment at screening to 
determine if a subject has liver fibrosis and steatosis. A 
screening FibroScan assessment is not needed if either a 
FibroScan assessment has been performed in the year prior 
to screening for which CAP scores are available or if a liver 
biopsy has been performed within the 2 years prior to the 
screening for which fibrosis grade is documented. 
Synopsis 
Trial Schedules 
Section 6.1.1 
A discussion between the Investigator or designee with the 
subject on the importance of a healthy liver before and after 
receiving a liver directed gene therapy, and factors that 
might impact liver health was added as a continuous 
assessment from screening onwards. 
Synopsis 
Trial Schedules 
Section 6.1.4 
It was clarified that the lead-in phase will last for a minimum 
of 6 months ending at or before Visit D. Subjects will remain 
in the lead-in phase until a minimum of 6 months of lead-in 
data have been collected and it is confirmed that the subjects 
still meet all eligibility criteria, with the final visit occurring 
approximately 4 weeks (6 weeks maximum) prior to the 
planned data of IMP dose administration (Visit D). 
Synopsis 
Trial Schedules 
Section 3.1 
Section 6.1.2 
Criteria for IMP dose administration was removed as the 
interim results of the dose confirmation trial are now 
available. 
Synopsis 
Figure 2 
Trial Schedules 
Section 3.1 
Section 6.1.2 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 144 of 150 
Summary of Changes 
Amendment Number: 
2.0 (Version 3.0) 
Amendment Date: 
07 Dec 2018 
Global/Country/Site-
Specific:  
Global 
Description of Change 
Section(s) Affected by 
Change 
It was clarified that at Visit L-Final, re-evaluation of 
subject’s eligibility will be based on assessments during both 
the lead-in period and this visit. 
Synopsis 
Section 6.1.2 
It was clarified that the wash out period will be 3 days for 
regular-acting factor IX products and 10 days for extended 
half-life factor IX products. 
Synopsis 
Trial Schedules 
Section 3.1 
It was specified that if the ICF is revised during the lead-in 
phase with lead-in phase with important new information 
that must be shared with the study subjects, the amended ICF 
will be presented, as required by the Institutional Review 
Board (IRB)/Independent Ethics Committee (IEC), for 
review and consideration by the subject, and signed 
re-consent is to be obtained prior to IMP dose 
administration. 
Synopsis 
Section 3.1 
Section 6.1.2 
Section 10.3.1 
During the post-treatment follow-up, visits that do not 
include physical examination or PRO questionnaires may be 
performed at the subject’s home by an appropriately 
qualified and trained nurse, with agreement from the 
investigator and the Sponsor. Each home nursing visit is 
expected to be supplemented by a phone call from the 
Investigator or designee to the subject to discuss AEs, 
concomitant medications, and e-diary compliance. 
Synopsis 
Trial Schedules 
Section 6.1.4 
Text describing management of endogenous factor IX 
activity was updated to always present what should be done 
if endogenous factor IX activity is ≥ 5% followed by if it is 
between 2 and 5% and then < 2%. 
Synopsis 
Section 5.6.2 
Section 6.1.4 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 145 of 150 
Summary of Changes 
Amendment Number: 
2.0 (Version 3.0) 
Amendment Date: 
07 Dec 2018 
Global/Country/Site-
Specific:  
Global 
Description of Change 
Section(s) Affected by 
Change 
It was clarified that for ALT level increments of at least 
2-fold baseline and > ULN, and for AST level increments of 
at least 2-fold ULN, the Investigator should contact the 
Medpace and uniQure Medical Directors to discuss a clinical 
management plan on a case-by-case basis, including 
potential re-tests and/or initiation of corticosteroid treatment. 
Section 5.6.3 was created as the section for Guidelines for 
ALT Elevations. 
Synopsis 
Section 5.6.3 
It was clarified that assessment of blood pressure, pulse, and 
body temperature was assessment of vital signs. 
Synopsis 
Trial Schedules 
Section 3.3.2 
Section 6.2.3.2 
Assessment of Exclusion Criterion #5 was clarified to occur 
at Visit L-Final only. Exclusion criteria 5 and 6 were 
combined into a single criterion. 
Exclusion Criterion #9 was updated to include advanced 
liver fibrosis (suggestive of or equal to METAVIR Stage 3 
disease; a FibroScan™ score of > 9 kPa was considered 
equivalent). 
Exclusion Criterion #11 related to known history of allergy 
to corticosteroids was added. 
Synopsis 
Section 4.2 
Descriptions of statistical analyses were expanded, including 
update of the Full Analysis Set and Per Protocol population 
definitions, specification that the primary analysis will be 
performed using a repeated measures linear mixed model, 
adjusting the order the secondary endpoints will be analyzed 
in, and changing EuroQol and iPAQ PRO questionnaires 
from an exploratory to secondary endpoint. 
Synopsis 
Section 2.2 
Section 3.3.2 
Section 9 
Alpha-fetoprotein was added as an assessment (measured at 
Visit L-Final, Visit F15, Visit F-Final, and all LTF visits) 
and as a safety endpoint. 
Synopsis 
Trial Schedules 
Section 3.3.2 
Table 8 
Section 9.10 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 146 of 150 
Summary of Changes 
Amendment Number: 
2.0 (Version 3.0) 
Amendment Date: 
07 Dec 2018 
Global/Country/Site-
Specific:  
Global 
Description of Change 
Section(s) Affected by 
Change 
Definition of gc was updated to genome copies from gene 
copies in the List of Abbreviations. 
List of Abbreviations 
It was clarified that study visits should be scheduled to 
ensure they take place when factor IX activity is at its 
trough, on the day that routine prophylactic factor IX 
replacement treatment is planned to be administered. 
Trial Schedules 
Section 6.2.2.3 
Dose of routine factor IX and its associated footnote was 
removed from the Trial Schedules. 
Trial Schedules 
It was clarified that PRO questionnaires being completed by 
the subject prior to other assessments are performed was a 
recommendation. 
Trial Schedules 
Section 6.1.2 
Section 6.1.4 
Section 6.1.5 
Section 6.2.2.4 
Section 6.2.2.6 
For the optional musculoskeletal ultrasound sub-study, it 
was clarified that if it is not possible to obtain the 
musculoskeletal ultrasound at screening (Visit S), it is 
allowed to obtain this first musculoskeletal ultrasound at a 
later time point (preferably as soon as possible thereafter 
during one of the lead-in visits). 
Trial Schedules 
Section 6.2.2.7 
Details for the second and last reference listed in Table 5 
were updated. 
Table 5 
The title for Section 1.3.2.1 was updated to “Preliminary 
Clinical Evidence for Efficacy and Safety of Components of 
AMT-061”, instead of AMT-060. 
Section 1.3.2.1 
Preliminary results from a Phase I/II trial of an 
AAV5-B-domain-deleted factor VIII construct was updated 
with initial results. 
Preliminary results from a single study showing sustained 
factor IX expression driven by a gene cassette encoding a 
Padua variant factor IX was updated with initial results. 
Section 1.3.2.1 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 147 of 150 
Summary of Changes 
Amendment Number: 
2.0 (Version 3.0) 
Amendment Date: 
07 Dec 2018 
Global/Country/Site-
Specific:  
Global 
Description of Change 
Section(s) Affected by 
Change 
In discussion of the results from trial AMT-060-01, 
clarification was made regarding how many subjects shifted 
to a moderate or severely moderate hemophilia phenotype 
during the study. 
Section 1.3.2.2 
Clarification that transaminase increase alone may warrant 
the initiation of a corticosteroid was made in Section 1.5.3, 
for consistency with Section 5.6.2. 
Section 1.5.3 
The study population was clarified to include subjects with 
more than 150 exposure days to a factor IX product in 
Section 1.5.8 for consistency with the inclusion/exclusion 
criteria. 
Section 1.5.8 
It was clarified in Section 1.5.9 that subjects will be 
administered a dose of their usual factor IX product/dose for 
their factor IX recovery assessment at Visit L-Final, not also 
at the screening visit. 
Section 1.5.9 
It was clarified that during the lead-in phase, an email 
communication is acceptable as an alternative to a follow-up 
phone call if the subject cannot be reached, though 
reasonable efforts for a phone call should be made. 
Section 3.1 
Section 6.1.2 
Clarifications were added surrounding concomitant 
medication/therapy. 
Section 5.6.2 
It was clarified that factor IX gene sequence analyses will be 
performed for all subjects that provide consent, even those 
that already have factor IX gene mutation information. 
Section 6.1.1 
Section 6.2.1.6 
For assessment of endogenous factor IX activity, the upper 
factor IX activity limit was set to > 5% for consistency with 
the other limits of 2 to 5% and < 2%. 
Section 6.1.4 
Collection at screening of on-demand factor IX replacement 
therapy at trial entry was removed from the list of medical 
history data related to hemophilia B being collected. 
Section 6.2.1.4 
Definitions for joint and muscle bleeds were removed. 
The definition for persistent bleed was added. 
Section 6.2.2.2 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 148 of 150 
Summary of Changes 
Amendment Number: 
2.0 (Version 3.0) 
Amendment Date: 
07 Dec 2018 
Global/Country/Site-
Specific:  
Global 
Description of Change 
Section(s) Affected by 
Change 
It was clarified that the short form of the International 
Physical Activity Questionnaire (iPAQ) will be used in this 
study. 
Section 6.2.2.4 
 
Summary of Changes 
Amendment Number: 
1.0 
Amendment Date: 
29 Mar 2018 
Global/Country/Site-
Specific:  
Global 
Description of Change 
Section(s) Affected by 
Change 
The title of the trial was updated, changing “an serotype” to 
“a serotype.” 
Current: Phase III, open-label, single-dose, multi-center 
multinational trial investigating a serotype 5 
adeno-associated viral vector containing the Padua variant of 
a codon-optimized human factor IX gene (AAV5-hFIXco-
Padua, AMT-061) administered to adult subjects with severe 
or moderately severe hemophilia B 
Previous: Phase III, open-label, single-dose, multi-center 
multinational trial investigating an serotype 5 
adeno-associated viral vector containing the Padua variant of 
a codon-optimized human factor IX gene (AAV5-hFIXco-
Padua, AMT-061) administered to adult subjects with severe 
or moderately severe hemophilia B 
Title 
Administrative change to the identity of the study monitor. 
Title Page 
Inclusion Criterion #4 updated. 
Current: > 150 previous exposure days of treatment with FIX 
protein. 
Previous: > 20 previous exposure days of treatment with FIX 
protein. 
Synopsis 
Section 4.1 
Specification that Exclusion Criterion #2 will be based on 
local laboratory results. 
Specification that Exclusion Criteria #3, 4, 5, and 8 will be 
based on central laboratory results. 
Synopsis 
Section 4.2 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 149 of 150 
Summary of Changes 
Amendment Number: 
1.0 
Amendment Date: 
29 Mar 2018 
Global/Country/Site-
Specific:  
Global 
Description of Change 
Section(s) Affected by 
Change 
Rewording of visit descriptions to improve clarity of 
assessments and their order. 
Synopsis 
Section 3.1 
Section 6.1 
Specification that subjects are expected to document factor 
IX usage and bleeding episode during the long-term 
follow-up, but not in the e-diary. 
Synopsis 
Section 6.1.5 
Section 6.2.2.1 
Section 6.2.2.2 
Update to language stating that Investigators will assess each 
bleeding episode, not adjudicate each bleeding episode. 
Synopsis 
Schedule of Events Table 1 
Section 6.1.2 
Section 6.1.6 
Section 6.2.2.2 
Clarification that analyses will be based on central laboratory 
measurements if results are available from both local and 
central laboratories. 
Synopsis 
Section 6.2.2.3 
Section 9.9 
Removal of the Hemophilia Joint Health Score (HJHS) 
assessment at Visit L3. 
Schedule of Events Table 1 
Adjustment of timing of physical examination assessments. 
Physical examination assessments will occur at screening 
(Visit S), Visit L-Final, Visit D (pre-IMP), Visits F1, F2, F4, 
F6, F12, F13, F15, F17, F19, F-Final, LTF1, LTF2, LTF3, 
LTF4, LTF6, and LTF8. 
Schedule of Events Table 1 
Section 6.1.4 
Section 6.1.5 
Section 6.2.3.3 
Addition of a chromogenic assay for FIX activity with 
assessments at Visits L1 to L-Final, Visit D, pre-IMP, Visits 
F1 to F-Final, and Visits LTF1 to LTF8. 
Schedule of Events Table 2 
and Table 4 
Section 6.2.2.3 
Section 6.2.3.6 
Clarification of the duration of trial participation. 
Current: The overall trial participation will be approximately 
5 and a half years. 
Previous: The overall trial participation will be a minimum 
of 5 and a half years. 
Section 3.1 
Addition of “Withdrawal by principal Investigator” as a 
possible reason for discontinuation. 
Section 4.5.1 

CSL222 (AAV5-hFIXco-Padua; etranacogene dezaparvovec) 
 
Protocol ID: CSL222_3001 
Version: 9.0 
 
Date: 12 Feb 2024 
Page 150 of 150 
Summary of Changes 
Amendment Number: 
1.0 
Amendment Date: 
29 Mar 2018 
Global/Country/Site-
Specific:  
Global 
Description of Change 
Section(s) Affected by 
Change 
The fill volume of IMP vials provided was clarified to be 
approximately 10 mL. 
Section 5.2 and Table 7 
Update of the names of the 2 PROBE forms. 
Addition of a description of both the Short Form and the 
Follow-up Form. 
Clarification that the Follow-up Form will be completed at 
Visit L3. 
Section 6.2.2.6 
Clarification that musculoskeletal ultrasounds will be 
centrally analyzed and results assessed by subject over the 
course of the study. Full details can be found in the 
Musculoskeletal Ultrasound Manual. 
Section 6.2.2.7 
Removal of vendor information for vector genome detection. 
Clarification of changes to the sampling schedule. 
Section 6.2.3.9 
Clarification that local laboratory results should be provided 
to the Investigator as soon as possible. 
Section 6.2.3.11 
The volume of blood to be drawn from each subject was 
updated due to the addition of the chromogenic assay for 
FIX activity. 
Current:  
• Approximately 2450 mL blood (excluding additional 
visits) total. 
• Maximum of 120 mL per visit and maximum of 110 mL 
per additional visit. 
• Approximately 2000 mL between screening and the end 
of the post-treatment follow-up 
• Approximately 450 mL during the long-term follow-up. 
Previous:  
• Approximately 2250 mL blood (excluding additional 
visits) total. 
• Maximum of 110 mL per visit and maximum of 100 mL 
per additional visit. 
• Approximately 1850 mL between screening and the end 
of the post-treatment follow-up 
• Approximately 400 mL during the long-term follow-up. 
Section 6.2.6 
 

Version: 1.0
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Print Date: 14-Feb-2024 07:36:11 GMT-05:00
Signature Page
CT-AMT-061-02 - Protocol Amendment
- AMD 8.0_Protocol V9.0 - 12Feb2024
Signed By:
Date (GMT):
Approved-
 Approval
13-Feb-2024 16:08:15
Approved-
 Approval
13-Feb-2024 20:45:00
Approved-
 Approval
13-Feb-2024 20:49:30
PPD
PPD
PPD
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