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NCT Number: NCT05962398

Long-term Follow-up Study of Male Adults With Hemophilia B Previously Treated With Etranacogene Dezaparvovec (CSL222)

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).

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Key information

Conditions

Hemophilia B Blood Coagulation Disorders Blood Coagulation Disorders, Inherited Coagulation Protein Disorders Congenital, Hereditary, and Neonatal Diseases and Abnormalities Genetic Diseases, Inborn Genetic Diseases, X-Linked Hematologic Diseases Hemic and Lymphatic Diseases Hemorrhagic Disorders

Age range

18 year and older

Sex eligibility

Male

Study type

Observational

Primary location

11-31 Cliniques Universitaires Saint-Luc, Brussels, Belgium

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Received treatment with CSL222 in Study CSL222_2001 or Study CSL222_3001, and completed participation in Study CSL222_2001 or Study CSL222_3001 or at least 5 years have passed since receiving CSL222.

Exclusion criteria

Not Applicable

Treatment and study plan

AAV5-hFIXco-Padua

Genetic

Single intravenous infusion of AAV5-hFIXco-Padua in the study CSL222_2001 (NCT03489291) or CSL222_3001 (NCT03569891).

Other names: Etranacogene dezaparvovec

Primary outcomes

  1. 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

  2. Percentage of Participants With SAEs and AESIs

    Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15

  3. Number of SAEs and AESIs

    Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15

Secondary outcomes

  1. Annualized Bleeding Rate (ABR)

    Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15

    The total, spontaneous, joint, and traumatic bleeds will be analyzed.

  2. 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

  3. Endogenous Factor IX (FIX) Activity

    Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15

    Endogenous FIX activity (expressed as percentage [%]) will be assessed using the one-stage activated partial thromboplastin time assay and a chromogenic assay.

  4. 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

    Endogenous FIX activity (expressed as %) will be assessed using the one-stage activated partial thromboplastin time assay and a chromogenic assay.

  5. Annualized Consumption of FIX Replacement Therapy

    Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15

    The annualized consumption of FIX replacement therapy (excluding FIX replacement for invasive procedures) will be provided.

  6. Annualized Infusion Rate 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 (excluding FIX replacement for invasive procedures) will be provided.

  7. 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

  8. 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

  9. Number of New Target Joints

    Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15

  10. Percentage Resolution of Pre-existing Target Joints

    Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15

  11. 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

    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.

  12. 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

    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.

  13. EQ-5D VAS Score

    Time frame: From Year 5 after administration of CSL222 in parent study up to Year 15

    The EQ-5D VAS, which measures overall health status on a vertical VAS, ranges from 0 to 100. A higher score indicates better QoL.

  14. 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

    The EQ-5D VAS, which measures overall health status on a vertical VAS, ranges from 0 to 100. A higher score indicates better QoL.

  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

    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.

  16. 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

    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.

Sponsors and collaborators

Lead sponsor

CSL Behring

Industry

Registry information

Official study title

An Extension Study Assessing the Long-term Safety and Efficacy of Etranacogene Dezaparvovec (CSL222) Previously Administered to Adult Male Subjects With Hemophilia B

Acronym: IX-TEND 3003

Important dates

Study start
2023
Primary completion
2035
Study completion
2035
First posted
Jul 27, 2023
Registry last updated
Jul 18, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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