Hemophilia BIX-TEND 3003NCT05962398
Long-term Follow-up Study of Male Adults With Hemophilia B Previously Treated With Etranacogene Dezaparvovec (CSL222)
An observational study of Hemophilia B, run by CSL Behring at 28 sites in 8 countries.
Trial summary
The primary purpose of this study is to assess the long-term safety and efficacy in male adults with hemophilia B who were treated with CSL222 (CSL222) in parent studies CSL222_2001 (NCT03489291) or CSL222_3001 (NCT03569891). Read more about this study
- Who is it for?
- Ages 18 years and older, men only
- Conditions the study is for
- Hemophilia B
- What is being tested?
- AAV5-hFIXco-Padua
- Type of treatment
- Injection or infusion
- How many people
- 56 participants
- Where
- 28 sitesin 8 countries
- Study dates
- 30 Aug 2023to 23 Mar 2035
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- Men only
- No healthy volunteers
- Adult, Older adult
Study population: Adult male participants with hemophilia B who were previously treated with CSL222 in study CSL222_2001 (NCT03489291) or CSL222_3001 (NCT03569891).
Who may be able to join
- Received treatment with CSL222 in Study CSL2222001 or Study CSL2223001, and completed participation in Study CSL2222001 or Study CSL2223001 or at least 5 years have passed since receiving CSL222.
Who cannot join
- Not Applicable
Trial locations and contacts
28 sites in 8 countries. Contact the study team or a site near you to ask about taking part.
28 sites in 8 countries
United States15 sites
10-10 University of Michigan Medical Center
Ann Arbor, Michigan, 48109
10-25 University of Colorado Denver
Aurora, Colorado, 80045
10-16 University of North Carolina at Chapel Hill
Chapel Hill, North Carolina, 27599
10-28 University of Texas Health Science Center
Houston, Texas, 77030
10-14 Arkansas Children's Hospital - Pharmacology
Little Rock, Arkansas, 72202
10-22 Orthopaedic Institute for Children
Los Angeles, California, 90007
10-21 Children's Hospital of Los Angeles
Los Angeles, California, 90027
10-20 Vanderbilt University Medical Center
Nashville, Tennessee, 37232
10-15 Phoenix Childrens Hospital
Phoenix, Arizona, 85016
10-18 Oregon Health & Science University
Portland, Oregon, 97239
10-63 UC Davis Medical Center
Sacramento, California, 95817
10-26 University of Utah
Salt Lake City, Utah, 84108
10-12 University of California, San Diego (UCSD)
San Diego, California, 92121
10-62 Washington Institute for Coagulation
Seattle, Washington, 98104
10-19 University of South Florida
Tampa, Florida, 33612
Netherlands4 sites
13-33 Amsterdam Universitair Medische Centra (UMC)
Amsterdam-Zuidoost, 1105 AZ
13-35 University Medical Center Groningen
Groningen, 9713 GZ
13-34 Erasmus University Medical Center
Rotterdam
13-36 Universitair Medisch Centrum Utrecht
Utrecht, 3584 CX
United Kingdom3 sites
18-54 Addenbrooke's Hospital
Cambridge, CB2 0QQ
18-52 Barts Health NHS Trust
London, England, E1 1FR.
18-53 University Hospital Southampton NHS Foundation Trust
Southampton, SO16 6YD
Belgium2 sites
11-31 Cliniques Universitaires Saint-Luc
Brussels, 1200
11-30 Universitair Ziekenhuis Leuven
Leuven, 3000
Germany1 site
15-42 Vivantes Klinikum im Friedrichshain - Landsberger Allee
Berlin, 10249
About this study
Official title: An Extension Study Assessing the Long-term Safety and Efficacy of Etranacogene Dezaparvovec (CSL222) Previously Administered to Adult Male Subjects With Hemophilia B
The primary purpose of this study is to assess the long-term safety and efficacy in male adults with hemophilia B who were treated with CSL222 (CSL222) in parent studies CSL222_2001 (NCT03489291) or CSL222_3001 (NCT03569891).
- Conditions
- Hemophilia B
- Being tested
- AAV5-hFIXco-Padua
- Medical subject headings
- Hemophilia B
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
AAV5-hFIXco-PaduaGenetic
Also called Etranacogene dezaparvovec
Single intravenous infusion of AAV5-hFIXco-Padua in the study CSL222_2001 (NCT03489291) or CSL222_3001 (NCT03569891).
| Study group | Role | What they receive |
|---|---|---|
| CSL222 | Participants who received CSL222 and completed either the study CSL222_2001 (NCT03489291) or CSL222_3001 (NCT03569891) will be followed up from Year 5 after administration of CSL222 in parent study up to Year 15. Receives: Genetic: AAV5-hFIXco-Padua |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Participants With Serious Adverse Events (SAEs) and AEs of Special Interest (AESIs)
Measured: From Year 5 after administration of CSL222 in parent study up to Year 15
Percentage of Participants With SAEs and AESIs
Measured: From Year 5 after administration of CSL222 in parent study up to Year 15
Number of SAEs and AESIs
Measured: From Year 5 after administration of CSL222 in parent study up to Year 15
Secondary outcomes (16)
Annualized Bleeding Rate (ABR)
The total, spontaneous, joint, and traumatic bleeds will be analyzed.
Measured: From Year 5 after administration of CSL222 in parent study up to Year 15
Number of Participants With Zero Total, Spontaneous, Joint, and Traumatic Bleeding Episodes
Measured: From Year 5 after administration of CSL222 in parent study up to Year 15
Endogenous Factor IX (FIX) Activity
Endogenous FIX activity (expressed as percentage [%]) will be assessed using the one-stage activated partial thromboplastin time assay and a chromogenic assay.
Measured: From Year 5 after administration of CSL222 in parent study up to Year 15
Change from Baseline by Visit in Endogenous FIX Activity
Endogenous FIX activity (expressed as %) will be assessed using the one-stage activated partial thromboplastin time assay and a chromogenic assay.
Measured: At Baseline (in parent study), From Year 5 after administration of CSL222 in parent study up to Year 15
Annualized Consumption of FIX Replacement Therapy
The annualized consumption of FIX replacement therapy (excluding FIX replacement for invasive procedures) will be provided.
Measured: From Year 5 after administration of CSL222 in parent study up to Year 15
Annualized Infusion Rate of FIX Replacement Therapy
Annualized infusion rate of FIX replacement therapy (excluding FIX replacement for invasive procedures) will be provided.
Measured: From Year 5 after administration of CSL222 in parent study up to Year 15
Number of Participants Remaining Free of Continuous FIX Prophylaxis
Measured: From Year 5 after administration of CSL222 in parent study up to Year 15
Percentage of Participants Remaining Free of Continuous FIX Prophylaxis
Measured: From Year 5 after administration of CSL222 in parent study up to Year 15
Number of New Target Joints
Measured: From Year 5 after administration of CSL222 in parent study up to Year 15
Percentage Resolution of Pre-existing Target Joints
Measured: From Year 5 after administration of CSL222 in parent study up to Year 15
EuroQol-5 Dimensions-5 Levels (EQ-5D-5L) Index Value
The EQ-5D-5L questionnaire consists of the EQ-5D-5L descriptive system and the EQ-5D visual analogue scale (VAS). The EQ-5D-5L descriptive system of health-related quality of life (QoL) consists of 5 dimensions (mobility, self-care, usual activities, pain/discomfort, anxiety/depression) for which responses will be recorded on 5 levels of severity (no problems, slight problems, moderate problems, severe problems, and extreme problems). The responses will be converted into a single overall health state utility value. This utility value will be derived using the EQ-5D-5L Crosswalk Index Value Calculator v2.xls [Hernández Alava et al, 2023], using the United Kingdom value set.
Measured: From Year 5 after administration of CSL222 in parent study up to Year 15
Change From Baseline in EQ-5D-5L Index Value
The EQ-5D-5L questionnaire consists of the EQ-5D-5L descriptive system and the EQ-5D VAS. The EQ-5D-5L descriptive system of health-related QoL consists of 5 dimensions (mobility, self-care, usual activities, pain/discomfort, anxiety/depression) for which responses will be recorded on 5 levels of severity (no problems, slight problems, moderate problems, severe problems, and extreme problems). The responses will be converted into a single overall health state utility value. This utility value will be derived using the EQ-5D-5L Crosswalk Index Value Calculator v2.xls [Hernández Alava et al, 2023], using the United Kingdom value set.
Measured: Baseline (in parent study), From Year 5 after administration of CSL222 in parent study up to Year 15
EQ-5D VAS Score
The EQ-5D VAS, which measures overall health status on a vertical VAS, ranges from 0 to 100. A higher score indicates better QoL.
Measured: From Year 5 after administration of CSL222 in parent study up to Year 15
Change From Baseline in EQ-5D VAS Score
The EQ-5D VAS, which measures overall health status on a vertical VAS, ranges from 0 to 100. A higher score indicates better QoL.
Measured: Baseline (in parent study), From Year 5 after administration of CSL222 in parent study up to Year 15
Hemophilia Quality of Life Questionnaire (Hem-A-QoL) Total Score
The Hem-A-QoL consists of 46 items comprising 10 domains: physical health, feelings, treatment, work and school, dealing with hemophilia, family planning, future, partnerships and sexuality, sports and leisure, and view of yourself for which responses will be recorded from 5 options (never, seldom, sometimes, often, and always; for some items, there is also a "not applicable" option). The total score is based on the scores for each domain and ranges from 0 to 100, with lower scores reflecting a better QoL.
Measured: From Year 5 after administration of CSL222 in parent study up to Year 15
Change From Baseline in Hem-A-QoL Total Score
The Hem-A-QoL consists of 46 items comprising 10 domains: physical health, feelings, treatment, work and school, dealing with hemophilia, family planning, future, partnerships and sexuality, sports and leisure, and view of yourself for which responses will be recorded from 5 options (never, seldom, sometimes, often, and always; for some items, there is also a "not applicable" option). The total score is based on the scores for each domain and ranges from 0 to 100, with lower scores reflecting a better QoL.
Measured: Baseline (in parent study), From Year 5 after administration of CSL222 in parent study up to Year 15
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Jul 2023
- Study start30 Aug 2023
- Primary completion23 Mar 2035 (estimated)
- Study completion23 Mar 2035 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Hemophilia BStudies of the same condition, open and under way.
- More trials run by CSL BehringThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 56 participants (estimated)
Sponsor and investigators
- Lead sponsor
- CSL Behring
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Study Director, Study director, CSL Behring
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05962398
- Sponsor's protocol ID
- CSL222_3003
- Other IDs
- EU CT Number
- Acronym
- IX-TEND 3003
- Status last verified
- Jul 2025
- First submitted
- 18 Jul 2023
- Last updated
- 18 Jul 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: CSL will consider on a case-by-case basis requests to share Individual Patient Data (IPD) with external bona-fide, qualified scientific and medical researchers. For information on the process and requirements for submitting a voluntary data sharing request for IPD, please contact CSL at clinicaltrials@cslbehring.com.
Publications
von Drygalski A, Gomez E, Giermasz A, Castaman G, Key NS, Lattimore SU, Leebeek FWG, Miesbach WA, Recht M, Monahan PE, Le Quellec S, Pipe SW. Completion of phase 2b trial of etranacogene dezaparvovec gene therapy in patients with hemophilia B over 5 years. Blood Adv. 2025 Jul 22;9(14):3543-3552. doi: 10.1182/bloodadvances.2024015291.
PubMed 40188458
Study at a glance
From the registry record, last updated by the sponsor on 18 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- An Extension Study Assessing the Long-term Safety and Efficacy of Etranacogene Dezaparvovec (CSL222) Previously Administered to Adult Male Subjects With Hemophilia B
- ClinicalTrials.gov ID
- NCT05962398
- Acronym / sponsor ID
- IX-TEND 3003 / CSL222_3003
- Conditions
- Hemophilia B
- Study type
- Observational
- Recruitment status
- Enrolling by invitation
- Enrolment
- 56 participants (estimated)
- Lead sponsor
- CSL BehringIndustry (pharma, biotech, devices)
- Study start
- 30 Aug 2023 (actual)
- Primary completion
- 23 Mar 2035 (estimated)
- Study completion
- 23 Mar 2035 (estimated)
- First posted
- 27 Jul 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The primary purpose of this study is to assess the long-term safety and efficacy in male adults with hemophilia B who were treated with CSL222 (CSL222) in parent studies CSL222_2001 (NCT03489291) or CSL222_3001 (NCT03569891).
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| CSL222 | – | Genetic: AAV5-hFIXco-PaduaParticipants who received CSL222 and completed either the study CSL222_2001 (NCT03489291) or CSL222_3001 (NCT03569891) will be followed up from Year 5 after administration of CSL222 in parent study up to Year 15. |
Who may qualify
- Ages
- 18 years and older
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Adult male participants with hemophilia B who were previously treated with CSL222 in study CSL222_2001 (NCT03489291) or CSL222_3001 (NCT03569891).
Key inclusion criteria (1 listed)
- Received treatment with CSL222 in Study CSL2222001 or Study CSL2223001, and completed participation in Study CSL2222001 or Study CSL2223001 or at least 5 years have passed since receiving CSL222.
Key exclusion criteria (1 listed)
- Not Applicable
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| AAV5-hFIXco-PaduaAlso: Etranacogene dezaparvovecSingle intravenous infusion of AAV5-hFIXco-Padua in the study CSL222_2001 (NCT03489291) or CSL222_3001 (NCT03569891). | Genetic | CSL222 |
Primary outcome
Number of Participants With Serious Adverse Events (SAEs) and AEs of Special Interest (AESIs)
Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15
Percentage of Participants With SAEs and AESIs
Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15
Number of SAEs and AESIs
Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15
16 secondary outcomes
Annualized Bleeding Rate (ABR)
Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15
Number of Participants With Zero Total, Spontaneous, Joint, and Traumatic Bleeding Episodes
Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15
Endogenous Factor IX (FIX) Activity
Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15
Change from Baseline by Visit in Endogenous FIX Activity
Time frame: At Baseline (in parent study), From Year 5 after administration of CSL222 in parent study up to Year 15
Annualized Consumption of FIX Replacement Therapy
Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15
Annualized Infusion Rate of FIX Replacement Therapy
Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15
Number of Participants Remaining Free of Continuous FIX Prophylaxis
Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15
Percentage of Participants Remaining Free of Continuous FIX Prophylaxis
Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15
Number of New Target Joints
Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15
Percentage Resolution of Pre-existing Target Joints
Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15
EuroQol-5 Dimensions-5 Levels (EQ-5D-5L) Index Value
Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15
Change From Baseline in EQ-5D-5L Index Value
Time frame: Baseline (in parent study), From Year 5 after administration of CSL222 in parent study up to Year 15
EQ-5D VAS Score
Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15
Change From Baseline in EQ-5D VAS Score
Time frame: Baseline (in parent study), From Year 5 after administration of CSL222 in parent study up to Year 15
Hemophilia Quality of Life Questionnaire (Hem-A-QoL) Total Score
Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15
Change From Baseline in Hem-A-QoL Total Score
Time frame: Baseline (in parent study), From Year 5 after administration of CSL222 in parent study up to Year 15
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 18 Jul 2025.
- Derived from this study: PubMed 40188458von Drygalski A, Gomez E, Giermasz A, Castaman G, Key NS, Lattimore SU, Leebeek FWG, Miesbach WA, Recht M, Monahan PE, Le Quellec S, Pipe SW. Completion of phase 2b trial of etranacogene dezaparvovec gene therapy in patients with hemophilia B over 5 years. Blood Adv. 2025 Jul 22;9(14):3543-3552. doi: 10.1182/bloodadvances.2024015291.
- Individual participant dataSharing planned: Yes. CSL will consider on a case-by-case basis requests to share Individual Patient Data (IPD) with external bona-fide, qualified scientific and medical researchers. For information on the process and requirements for submitting a voluntary data sharing request for IPD, please contact CSL at clinicaltrials@cslbehring.com.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Study Director study director
CSL Behring
28 sites in 8 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Hemophilia B, run by CSL Behring at 28 sites in 8 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 18 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 28 sites in United States, Netherlands, United Kingdom, Belgium, Denmark and 3 more countries. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of Participants With Serious Adverse Events (SAEs) and AEs of Special Interest (AESIs) (time frame: From Year 5 after administration of CSL222 in parent study up to Year 15). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05962398, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 Jul 2025.