Hemophilia BIX-TEND 4001NCT06008938
An Observational Cohort Study to Characterize the Effectiveness and Safety of HEMGENIX® in Patients With Hemophilia B
An observational study of Hemophilia B, run by CSL Behring at 12 sites in 7 countries.
Trial summary
This observational, post-authorization, long-term follow-up study aims to investigate the short and long-term effectiveness and safety of HEMGENIX in patients with hemophilia B. The study will also include a cohort of patients with hemophilia B treated with FIX prophylaxis to enable interpretation of relevant efficacy… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Hemophilia B
- What is being tested?
- HEMGENIX and Factor IX (FIX)
- How many people
- 500 participants
- Where
- 12 sitesin 7 countries
- Study dates
- 15 Jun 2023to 1 Aug 2043
- 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
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Patients with hemophilia B who have been treated with HEMGENIX and are enrolled in either the sponsor's study or the ATHN Transcends study NCT04398628 (Hemophilia Cohort, Gene Therapy Outcomes Arm), and patients who receive routine prophylaxis treatment with FIX replacement therapy that are enrolled in the ATHN Transcends study (Hemophilia Cohort, Natural History Arm), or a similar registry. All patients will provide signed informed consent required for participation.
Who may be able to join
- HEMGENIX Cohort:
- - Treatment with commercial HEMGENIX.
- - Have provided signed written informed consent within 3 months before or within 6 months after HEMGENIX treatment, or within 6 months of when the study is initiated at the participating site.
- FIX Prophylaxis Cohort:
- - Adult patients (≥ 18 years) with hemophilia B who have consented and enrolled in ATHN Transcends Hemophilia Cohort (or a similar registry) and are receiving FIX prophylaxis therapy.
Who cannot join
- HEMGENIX Cohort:
- - The patient population that will be observed in this study must not have been treated with etranacogene dezaparvovec in a clinical trial.
Trial locations and contacts
12 sites in 7 countries. Contact the study team or a site near you to ask about taking part.
12 sites in 7 countries
Germany4 sites, 4 recruiting
- Recruiting
Klinik für Angiologie/ Hämostaseologie
Berlin
- Recruiting
University of Clinic Bonn
Bonn
- Recruiting
Klinikum der Johann-Wolfgang Goethe Universitaet
Frankfurt
- Recruiting
Hannover Medical School
Hanover
France3 sites, 3 recruiting
- Recruiting
Centre Hospitalier Universitaire de Brest / CHU Morvan
Brest
- Recruiting
Centre Régional de Traitement de l'Hémophilie
Nantes
- Recruiting
CHU Nancy - Hôpital Brabois
Vandœuvre-lès-Nancy
United States1 site, 1 recruiting
- Recruiting
American Thrombosis and Hemostasis Network
Rochester, New York, 14604
Spain1 site, 1 recruiting
- Recruiting
Hospital Alvaro Cunqueiro Dr. Manuel Rodriquez-Lopez
Vigo
Switzerland1 site, 1 recruiting
- Recruiting
University Hospital Bern Inselspital
Bern
About this study
Official title: An Observational Post-authorization Long-term Follow-up Study to Characterize the Effectiveness and Safety of HEMGENIX® (Etranacogene Dezaparvovec) in Patients With Hemophilia B
This observational, post-authorization, long-term follow-up study aims to investigate the short and long-term effectiveness and safety of HEMGENIX in patients with hemophilia B. The study will also include a cohort of patients with hemophilia B treated with FIX prophylaxis to enable interpretation of relevant efficacy and safety findings of HEMGENIX.
- Conditions
- Hemophilia B
- Being tested
- HEMGENIX, Factor IX (FIX)
- Keywords
- Hemophilia B, HEMGENIX
- Medical subject headings
- Hemophilia B
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
HEMGENIXGenetic
Also called Etranacogene dezaparvovec
HEMGENIX is a gene therapy medicinal product that aims to deliver a factor IX (FIX) gene expression cassette to the liver of patients with hemophilia B.
Factor IX (FIX)Biological
FIX prophylaxis therapy
| Study group | Role | What they receive |
|---|---|---|
| HEMGENIX | Patients with hemophilia B treated with HEMGENIX in countries where HEMGENIX is approved for commercial use. Receives: Genetic: HEMGENIX | |
| FIX Prophylaxis | Patients with hemophilia B on FIX prophylaxis and enrolled in American Thrombosis and Hemostasis Network (ATHN) Transcends (A Natural History Cohort Study of the Safety, Effectiveness, and Practice of Treatment in People with Non-Neoplastic Hematologic Disorders) Hemophilia Cohort, or a similar registry. Receives: Biological: Factor IX (FIX) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Bleeding Rate (all bleeds) - HEMGENIX Cohort
Annualised Bleeding Rate (ABR) for all bleeds
Measured: During the 52 weeks following stable FIX expression (6 to 18 months) in the follow-up period and at Months 6 to: 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180 after HEMGENIX treatment.
Secondary outcomes (15)
Bleeding Rate (specified bleed types) - HEMGENIX Cohort
ABR for spontaneous, FIX-treated, traumatic, and joint bleeds
Measured: During follow-up period (52 weeks following stable FIX expression [6 to 18 months]), and at Months 6 to: 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180 after HEMGENIX treatment.
Zero bleeds - HEMGENIX Cohort
Number of patients with zero bleeds
Measured: During follow-up after HEMGENIX treatment, up to 180 months
Correlation analysis - HEMGENIX Cohort
Correlation analysis of ABR as a function of mean FIX activity.
Measured: Over the 6 to: 18, 24, 36, 48, 60, 72, 96, 108, 120, 132, 144, 156, 168, and 180 months after HEMGENIX treatment.
Bleeding Rate - FIX Prophylaxis Cohort
ABR (total, spontaneous, FIX-treated, traumatic, and joint bleeds)
Measured: In the period Months 0 to: 12, 18, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180 Months.
FIX activity - HEMGENIX Cohort
Mean uncontaminated endogenous FIX activity (%)
Measured: Day 1, Week 6, and Months 6, 12, 18, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180 after HEMGENIX treatment.
Annualized consumption of FIX replacement therapy - HEMGENIX Cohort
Mean annualized consumption (IU/kg/Yr) of FIX replacement therapy (including FIX replacement for various clinical scenarios eg, prophylaxis, spontaneous bleeding events, medical procedures, surgery, and trauma).
Measured: During the follow-up periods (52 weeks following stable FIX expression [6 to 18 months], & at Months 0 to: 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180), & at yearly intervals (ie, at 0 to 1 yr, 1 to 2 yrs, etc, up to 14 to 15 yrs).
Annualized consumption of FIX replacement therapy - FIX Prophylaxis Cohort
Mean annualized consumption (IU/kg/Yr) of FIX replacement therapy (including FIX replacement for various clinical scenarios eg, prophylaxis, spontaneous bleeding events, medical procedures, surgery, and trauma).
Measured: At Months 0 to: 12, 18, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180.
Number of patients remaining free of previous continuous routine prophylaxis - HEMGENIX Cohort
Number and proportion of patients remaining free of previous continuous routine prophylaxis (FIX replacement therapy)
Measured: At Months 6 to: 18, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180 after HEMGENIX treatment.
Target joints occurrence - HEMGENIX Cohort
The annualized occurrence of target joints (defined as 3 or more spontaneous bleeding events into a single joint within a consecutive 6-month period).
Measured: After HEMGENIX treatment, during the follow-up periods (52 weeks following stable FIX expression [6 to 18 months], and at Months 6 to: 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180).
Target joints resolution - HEMGENIX Cohort
The percentage of resolution of target joints (target resolution is defined as a recorded target joint with 2 or fewer spontaneous bleeding events within a consecutive 12-month period).
Measured: During the follow-up period, up to 180 months
Target joints - FIX Prophylaxis Cohort
The annualized occurrence of target joints
Measured: From Months 0 to 12, 18, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180.
Related Serious Adverse Events (SAEs) - number
Incidence (number) of related SAEs
Measured: During 15 years of follow-up
Related SAEs - percent
Incidence (percent) of related SAEs
Measured: During 15 years of follow-up
Adverse Events of Special Interest (AESIs) - number
Incidence (number) of AESIs
Measured: During 15 years of follow-up
AESIs - percent
Incidence (percent) of AESIs
Measured: During 15 years of follow-up
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Aug 2023
- Study start15 Jun 2023
- Primary completion1 Aug 2043 (estimated)
- Study completion1 Aug 2043 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- 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
- 500 participants (estimated)
Sponsor and investigators
- Lead sponsor
- CSL Behring
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Global Program Director, Study director, CSL Behring
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06008938
- Sponsor's protocol ID
- CSL222_4001
- Other IDs
- EUPAS106066
- Acronym
- IX-TEND 4001
- Status last verified
- Feb 2026
- First submitted
- 15 Aug 2023
- Last updated
- 19 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- Individual data sharing
- Yes: CSL will consider requests to share Individual Patient Data (IPD) from systematic review groups or bona-fide researchers. For information on the process and requirements for submitting a voluntary data sharing request for IPD, please contact CSL at clinicaltrials@cslbehring.com. Applicable country specific privacy and other laws and regulations will be considered and may prevent sharing of IPD. If the request is approved and the researcher has executed an appropriate data sharing agreement, IPD that has been appropriately anonymized will be available.
Study at a glance
From the registry record, last updated by the sponsor on 19 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- An Observational Post-authorization Long-term Follow-up Study to Characterize the Effectiveness and Safety of HEMGENIX® (Etranacogene Dezaparvovec) in Patients With Hemophilia B
- ClinicalTrials.gov ID
- NCT06008938
- Acronym / sponsor ID
- IX-TEND 4001 / CSL222_4001
- Conditions
- Hemophilia B
- Keywords
- Hemophilia B, HEMGENIX
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 500 participants (estimated)
- Lead sponsor
- CSL BehringIndustry (pharma, biotech, devices)
- Study start
- 15 Jun 2023 (actual)
- Primary completion
- 1 Aug 2043 (estimated)
- Study completion
- 1 Aug 2043 (estimated)
- First posted
- 24 Aug 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.
This observational, post-authorization, long-term follow-up study aims to investigate the short and long-term effectiveness and safety of HEMGENIX in patients with hemophilia B. The study will also include a cohort of patients with hemophilia B treated with FIX prophylaxis to enable interpretation of relevant efficacy and safety findings of HEMGENIX.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| HEMGENIX | – | Genetic: HEMGENIXPatients with hemophilia B treated with HEMGENIX in countries where HEMGENIX is approved for commercial use. |
| FIX Prophylaxis | – | Biological: Factor IX (FIX)Patients with hemophilia B on FIX prophylaxis and enrolled in American Thrombosis and Hemostasis Network (ATHN) Transcends (A Natural History Cohort Study of the Safety, Effectiveness, and Practice of Treatment in People with Non-Neoplastic Hematologic Disorders) Hemophilia Cohort, or a similar registry. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Patients with hemophilia B who have been treated with HEMGENIX and are enrolled in either the sponsor's study or the ATHN Transcends study NCT04398628 (Hemophilia Cohort, Gene Therapy Outcomes Arm), and patients who receive routine prophylaxis treatment with FIX replacement therapy that are enrolled in the ATHN Transcends study (Hemophilia Cohort, Natural History Arm), or a similar registry. All patients will provide signed informed consent required for participation.
Key inclusion criteria (5 listed)
- HEMGENIX Cohort:
- - Treatment with commercial HEMGENIX.
- - Have provided signed written informed consent within 3 months before or within 6 months after HEMGENIX treatment, or within 6 months of when the study is initiated at the participating site.
- FIX Prophylaxis Cohort:
- - Adult patients (≥ 18 years) with hemophilia B who have consented and enrolled in ATHN Transcends Hemophilia Cohort (or a similar registry) and are receiving FIX prophylaxis therapy.
Key exclusion criteria (2 listed)
- HEMGENIX Cohort:
- - The patient population that will be observed in this study must not have been treated with etranacogene dezaparvovec in a clinical trial.
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 |
|---|---|---|
| HEMGENIXAlso: Etranacogene dezaparvovecHEMGENIX is a gene therapy medicinal product that aims to deliver a factor IX (FIX) gene expression cassette to the liver of patients with hemophilia B. | Genetic | HEMGENIX |
| Factor IX (FIX)FIX prophylaxis therapy | Biological | FIX Prophylaxis |
Primary outcome
Bleeding Rate (all bleeds) - HEMGENIX Cohort
Time frame: During the 52 weeks following stable FIX expression (6 to 18 months) in the follow-up period and at Months 6 to: 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180 after HEMGENIX treatment.
Annualised Bleeding Rate (ABR) for all bleeds
15 secondary outcomes
Bleeding Rate (specified bleed types) - HEMGENIX Cohort
Time frame: During follow-up period (52 weeks following stable FIX expression [6 to 18 months]), and at Months 6 to: 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180 after HEMGENIX treatment.
Zero bleeds - HEMGENIX Cohort
Time frame: During follow-up after HEMGENIX treatment, up to 180 months
Correlation analysis - HEMGENIX Cohort
Time frame: Over the 6 to: 18, 24, 36, 48, 60, 72, 96, 108, 120, 132, 144, 156, 168, and 180 months after HEMGENIX treatment.
Bleeding Rate - FIX Prophylaxis Cohort
Time frame: In the period Months 0 to: 12, 18, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180 Months.
FIX activity - HEMGENIX Cohort
Time frame: Day 1, Week 6, and Months 6, 12, 18, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180 after HEMGENIX treatment.
Annualized consumption of FIX replacement therapy - HEMGENIX Cohort
Time frame: During the follow-up periods (52 weeks following stable FIX expression [6 to 18 months], & at Months 0 to: 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180), & at yearly intervals (ie, at 0 to 1 yr, 1 to 2 yrs, etc, up to 14 to 15 yrs).
Annualized consumption of FIX replacement therapy - FIX Prophylaxis Cohort
Time frame: At Months 0 to: 12, 18, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180.
Number of patients remaining free of previous continuous routine prophylaxis - HEMGENIX Cohort
Time frame: At Months 6 to: 18, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180 after HEMGENIX treatment.
Target joints occurrence - HEMGENIX Cohort
Time frame: After HEMGENIX treatment, during the follow-up periods (52 weeks following stable FIX expression [6 to 18 months], and at Months 6 to: 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180).
Target joints resolution - HEMGENIX Cohort
Time frame: During the follow-up period, up to 180 months
Target joints - FIX Prophylaxis Cohort
Time frame: From Months 0 to 12, 18, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180.
Related Serious Adverse Events (SAEs) - number
Time frame: During 15 years of follow-up
Related SAEs - percent
Time frame: During 15 years of follow-up
Adverse Events of Special Interest (AESIs) - number
Time frame: During 15 years of follow-up
AESIs - percent
Time frame: During 15 years of follow-up
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 19 Feb 2026.
- Individual participant dataSharing planned: Yes. CSL will consider requests to share Individual Patient Data (IPD) from systematic review groups or bona-fide researchers. For information on the process and requirements for submitting a voluntary data sharing request for IPD, please contact CSL at clinicaltrials@cslbehring.com. Applicable country specific privacy and other laws and regulations will be considered and may prevent sharing of IPD. If the request is approved and the researcher has executed an appropriate data sharing agreement, IPD that has been appropriately anonymized will be available.
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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.
Global Program Director study director
CSL Behring
12 sites in 7 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 12 sites in 7 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 5 inclusion and 2 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: looking for participants now, as of the sponsor's last update on 19 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 12 sites in Germany, France, United States, Austria, Denmark and 2 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?
Contact Trial Registration Coordinator (+1 610-878-4697, clinicaltrials@cslbehring.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Bleeding Rate (all bleeds) - HEMGENIX Cohort (time frame: During the 52 weeks following stable FIX expression (6 to 18 months) in the follow-up period and at Months 6 to: 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180 after HEMGENIX treatment.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 19 Feb 2026.